Selective removal of heavy metal ions from aqueous solutions with surface functionalized s
壳聚糖水热交联炭材料研究
壳聚糖水热交联炭材料研究张文龙;马儒超;周志伟;韩琪胜【摘要】壳聚糖水热炭是通过水热交联壳聚糖制备得到的含有丰富氨基的炭材料.制备过程只需一步,条件温和无需任何特殊溶剂和有毒交联剂;材料自带氨基容易改性,有较好的耐酸性,是非常好的吸附剂材料.【期刊名称】《江西化工》【年(卷),期】2014(000)001【总页数】5页(P232-236)【关键词】壳聚糖;水热法;吸附剂【作者】张文龙;马儒超;周志伟;韩琪胜【作者单位】东华理工大学,江西南昌330013;东华理工大学,江西南昌330013;东华理工大学,江西南昌330013;东华理工大学,江西南昌330013【正文语种】中文1 壳聚糖壳聚糖(Chitosan, CTS)又称为聚葡萄糖胺(1-4)-2-氨基-B-D葡萄糖，是一种天然高分子化合物，由甲壳素经脱乙酰处理制备而成。
壳聚糖是目前为止唯一发现的天然碱性多糖，具有线性共聚高分子的材料结构，其链上氨基、羟基能交联形成具有类似网状结构的笼形分子对金属离子起稳定的配位作用[1]。
壳聚糖因氨基易质子化而溶于酸性溶液，一般实际应用中需经过改性和交联来改变材料的溶解性，制备出耐酸碱的材料[2]。
通过交联的方法可以使壳聚糖具有许多优点，如可以制备具有不同结构形状的吸附材料(凝胶，微球，膜，纤维等)并能改变其机械强度，可以在酸性，碱性或有机溶剂中使用，具有耐高温性。
交联壳聚糖在吸附过程中还有以下优势：(1)吸附速度更快，由于交联壳聚糖有较好的溶胀性能，吸附网络扩张后利于金属离在材料内部的扩散。
(2)交联壳聚糖易于改性接枝，可通过在表面接枝不同的官能团提升吸附性能。
(3)交联壳聚糖的吸附行为受溶液pH值的影响较小，适用于低放废液苛刻的酸性环境。
但是，随着壳聚糖交联度的增加，吸附容量会相应减少，在高交联度的情况下其溶胀性能大幅下降并阻碍整个吸附过程，交联剂的使用在整个工艺中尤为重要。
Pang[3]采用壳聚糖包覆凹凸棒石复合材料研究其对溶液中铀酰离子的去除效果，实验表明吸附行为符合准二级动力学模型，吸附容量有所提升，壳聚糖对吸附过程有促进效果。
L-半胱氨酸改性氧化石墨烯去除水中Hg(Ⅱ)
第50卷第4期2021年4月应用化工Applied Chemical IndustryVol.50No.4Apr.2021半胱氨酸改性氧化石墨烯去除水中H g(n)赵博涵蔦林海英▽，冯庆革i,朱奕帆i,廖玉莲i(1•广西大学资源环境与材料学院广西高校环境保护重点实验室,广西南宁530004；2.广西博世科环保科技股份有限公司，广西南宁530007)摘要:通过简单一步合成法，以L-半胱氨酸(L-Cysteine)作为改性剂,合成了工业级半胱氨酸功能化氧化石墨烯吸附剂L-Cyslein e-G0o考察了不同条件下L-Cysleine-GO对Hg(H)吸附性能的变化，如pH、吸附剂投加量、接触时间等;通过FTIR、拉曼光谱和SEM等表征手段,以探究该材料的吸附性能及机理。
实验结果表明，当初始Hg(fl)浓度为200mg/L、pH为7、投加量为1g/L、吸附时间为60min、温度为25t时,最大吸附量为160.71mg/g。
准二级动力学、Freundlich模型与微观表征结果提示吸附机理为疏基等官能团对Hg(D)的化学键合、材料对汞的静电吸附作用，主要为多层化学吸附。
关键词:氧化石墨烯;水中Hg(I)的去除;L-半胱氨酸改性;一步合成法;吸附机理解析中图分类号:TQ424文献标识码:A文章编号：1671-3206(2021)04-0991-06Removal of Hg(U)from water by L-Cysteinemodified graphene oxideZHAO Bo-han,UN Hai-ying1'2,FENG Qing-ge,ZHU Yi-fan,UA0Yu-lian(1.Key Laboratory of Environmental Protection,College of Resources,Environment and Materials,Guangxi University,Nanning 530004,China；2.Guangxi Bossco Environmental Protection Technology Co.,Ltd.,Nanning530007,China)Abstract:Graphene oxide modified with L-Cysteine(L-Cysteine-GO)was prepared by one-step synthesis with L-Cysteine as the modifying agent.The adsorption performance of L-Cysteine-GO on Hg(U)was investigated at different factors such as pH,the dosage of material and contact time.FTIR,Raman spectroscopy and SEM were used to investigate the adsorption properties and mechanism of the materials.The results showed that the maximum adsorption capacity was160.71mg/g when the material was added into initial concentration of200mg/L at pH7,at25弋with the dosage of1g/L in60min.With combination of pseudo-second order kinetics,Freundlich model and material microstructure,it was suggested that the adsorption process can described to the chemical bonding of sulfhydryl groups and Hg(H),electrostatic adsorption between material and Hg(U),which was dominantly controlled by the multi-layer chemical adsorption.Key words:graphene oxide；removal of Hg(H)in water；L-Cysteine modification；one-step synthesis；adsorption mechanism identification现代化工、燃煤、氯碱和混汞炼金等行业所产生的重金属汞污染⑴，因其可对人体产生较高的毒性,导致神经、大脑和肾脏的接触性损害,而备受关注3〕。
大孔阳离子吸附树脂
大孔阳离子吸附树脂1. 引言大孔阳离子吸附树脂是一种常见的固相吸附材料，广泛应用于水处理、环境保护、化学工业等领域。
它具有高效的吸附性能和良好的选择性，能够去除水中的阳离子污染物，提高水质。
2. 原理大孔阳离子吸附树脂基于静电作用原理，通过树脂表面上的功能基团与溶液中的阳离子发生化学反应，实现对阳离子的吸附和去除。
大孔结构使得树脂具有较大的表面积和孔隙体积，提供了更多的吸附位点，增强了吸附能力。
3. 材料特性3.1 大孔结构大孔阳离子吸附树脂具有较大的孔径和孔隙体积，使其具有更好的承载能力和质量传递性能。
这种结构可以增加有效接触面积，并提高物质传递速率。
3.2 功能基团大孔阳离子吸附树脂表面上的功能基团通常是带正电荷的官能团，如胺基、羧基等。
这些功能基团能够与溶液中的阴离子发生静电作用，实现对阳离子的吸附。
3.3 选择性大孔阳离子吸附树脂具有一定的选择性，它可以根据不同的功能基团和溶液中阳离子的特性来调整吸附效果。
通过选择合适的功能基团和优化操作条件，可以实现对特定阳离子的高效去除。
4. 应用领域4.1 水处理大孔阳离子吸附树脂在水处理中广泛应用。
它可以去除水中的重金属离子、放射性物质、有机污染物等。
通过调整树脂类型和操作条件，可以实现对不同污染物的高效去除。
4.2 环境保护大孔阳离子吸附树脂在环境保护领域也有重要应用。
它可以去除工业废水中的有害物质，减少水体污染。
此外，它还可以应用于土壤修复、废气处理等方面，提高环境质量。
4.3 化学工业大孔阳离子吸附树脂在化学工业中有多种应用。
例如，它可以用于分离和纯化有机化合物，提高产品的纯度和质量。
此外，它还可以用于催化剂的固定和回收，提高反应效率和资源利用率。
5. 实例分析以水处理为例，说明大孔阳离子吸附树脂的应用。
在水处理过程中，大孔阳离子吸附树脂可以去除水中的重金属离子。
通过选择合适的功能基团和优化操作条件，可以实现对特定重金属离子的高效去除。
6. 结论大孔阳离子吸附树脂是一种具有高效吸附性能和良好选择性的固相吸附材料。
醇水混合溶剂中制备钨酸铋中空纳米结构
醇水混合溶剂中制备钨酸铋中空纳米结构陈磊;吴大雄;朱海涛【摘要】Bi2WO6 nano-structures were synthesized in ethano-water mixed solvent with Bi(NO3)3 and Na2WO4 as reactants. Bi2 WO6 hollow nano-structures can be prepared through solvothermal process by adjusting the ratio of ethanol to water, reaction temperature and reaction time. The results indicated that Bi2WO6 hollow nano-spheres with 30 - 50 nm in diameter and 10 nm in thickness could be synthesized when the ratio of ethanol to water was 10:1, reaction temperature 100 ℃, and rea ction time was 12 h.%以硝酸铋和钨酸钠为反应物,在乙醇-水混合溶剂体系中反应生成钨酸铋纳米结构.通过调整乙醇和水的比例、反应温度、反应时间等参数,在溶剂热条件下可以直接生成钨酸铋中空纳米结构.实验结果表明,当醇水体积比为10∶1,溶剂热温度为100℃,反应时间为12 h时,制备的Bi2WO6纳米空心球粒度均匀,直径在30～50 nm,壳的厚度在10 nm左右.【期刊名称】《青岛科技大学学报（自然科学版）》【年(卷),期】2012(033)001【总页数】4页(P9-12)【关键词】钨酸铋;中空纳米结构;混合溶剂【作者】陈磊;吴大雄;朱海涛【作者单位】青岛科技大学材料科学与工程学院,山东青岛266042;青岛科技大学材料科学与工程学院,山东青岛266042;青岛科技大学材料科学与工程学院,山东青岛266042【正文语种】中文【中图分类】TB321中空纳米结构是指内部空腔及壁厚都在纳米尺度范围内的壳层结构。
气浮—UASB—AO工艺处理日用化工废水实例
2021年 第6期 广 东 化 工 第48卷 总第440期 · 79 ·气浮－UASB －AO 工艺处理日用化工废水实例郑家传(苏州市环科环保技术发展有限公司，江苏 苏州 215007)[摘 要]某日用化工企业排放的生产废水表面活性剂浓度较高，针对该类高浓度有机废水，采用气浮－UASB －AO 组合工艺进行处理，工程实践表明：当进水COD 为6000 mg/L 左右的情况下，出水水质达到《污水综合排放标准》(GB 8978-1996)的三级标准要求。
[关键词]气浮；厌氧；缺氧；好氧；日用化工废水[中图分类号]X5 [文献标识码]A [文章编号]1007-1865(2021)06-0079-02Engineering Application of Air Flotation －UASB －AO to the Treatment of DailyChemical Industrial WastewaterZheng Jiachuan(Suzhou HuanKe Environmental Protection Technology Development Co., Ltd., Suzhou 215007, China)Abstract: The wastewater discharged from daily chemical industry contains a large quantity of organisms, such as surface active agent. It is characterized by complicated components. The combined air flotation －UASB －AO process has been used for its treatment ．The practice proves that when the influent COD is about 6000 mg/L, and the system remains relatively stable condition ， the effluent water quality meets the requirements for the First Level standard specified in the Integrated Wastewater Discharge Standard (GB 8978—1996).Keywords: air flotation ；anaerobic process ； aerobic process ； anoxic process ；daily chemical industrial wastewater1 工程概况某日用化工生产企业的主要产品为沐浴露、洗面奶、洗发水等。
SiO2 graphene composite for highly selective adsorption of Pb(II) ion
SiO 2/graphene composite for highly selective adsorption of Pb(II)ionLiying Hao,Hongjie Song,Lichun Zhang,Xiangyu Wan,Yurong Tang,Yi Lv ⇑Key Laboratory of Green Chemistry &Technology,Ministry of Education,College of Chemistry,Sichuan University,Chengdu,Sichuan 610064,Chinaa r t i c l e i n f o Article history:Received 24October 2011Accepted 8December 2011Available online 16December 2011Keywords:Pb(II)ionSiO 2/graphene composite Adsorptiona b s t r a c tSiO 2/graphene composite was prepared through a simple two-step reaction,including the preparation of SiO 2/graphene oxide and the reduction of graphene oxide (GO).The composite was characterized by UV–Vis spectroscopy,Fourier transform infrared spectroscopy,scanning electron microscope,and X-ray pho-toelectron spectroscopy,and what is more,the adsorption behavior of as-synthesized SiO 2/graphene composite was investigated.It was interestingly found that the composite shows high efficiency and high selectivity toward Pb(II)ion.The maximum adsorption capacity of SiO 2/graphene composite for Pb(II)ion was found to be 113.6mg g À1,which was much higher than that of bare SiO 2nanoparticles.The results indicated that SiO 2/graphene composite with high adsorption efficiency and fast adsorption equilibrium can be used as a practical adsorbent for Pb(II)ion.Ó2011Elsevier Inc.All rights reserved.1.IntroductionGraphene (G),discovered in 2004[1],has been attempted in many applications due to its excellent characteristics,such as mobil-ity of charge carriers,mechanical flexibility,thermal and chemical stability,and large surface area [2–4].Significantly,graphene,as ideal two-dimensional ultrathin material with large surface area,is a promising building block material for composites [5];further-more,decoration of the graphene nanosheets with metal/metal oxide/nonmetallic oxide nanomaterials can bring about an impor-tant kind of graphene-based composites [6–10].The decoration of nanomaterials onto graphene nanosheets is also helpful to over-come the aggregation of individual graphene nanosheets [11]and nanomaterials themselves.Besides,the composites with larger sur-face area show superior properties,compared with bare nanomate-rials [12],due to the synergistic effect between graphene nanosheets and nanomaterials.Therefore,in recent years,many endeavors have been poured on the synthesis of graphene-based nanocomposites,e.g.,graphene/metal oxide and graphene/metal composites,and these composite materials have been explored as adsorbents [13,14],catalysts [15],and lithium ion batteries [16]along with an excellent application potential.Considering the inexpensive cost,innocuity,reliable and chemical stability,biocompatibility,and ver-satility of SiO 2[17],graphene/silica composite would be one of the greatly popular and interest topics in the field of nanomaterial and nanotechnology.On the other hand,there has been a long-time concern on the pollution of heavy metals to the aquatic environment because oftheir toxicity and detriment to living species including humans.Among all of the heavy metal ions,lead ion,which commonly exists in industrial and agricultural wastewater and in acidic leach-ate from landfill sites [18],is ubiquitous in the environment and severely hazardous to human and living things.Long-term drink-ing water containing high level of lead ion would cause serious dis-orders,such as anemia,kidney disease,nausea,convulsions,coma,renal failure,and cancer,along with subtly negative effects on metabolism and intelligence [19].Up to now,many techniques have been applied to remove Pb(II)ion from waste water,such as ion exchange [20],cloud point extraction [21],coprecipitation [22],flocculation [23],membrane filtration [24],reverse osmosis [25],adsorption [26],and so forth.Among these methods,adsorption-based methodology is greatly popular thanks to its high efficiency,cost-effectiveness,simple operation,and environmental friendliness [27].Especially,adsorptive removal of aqueous Pb(II)ion has been widely investigated by using various materials,such as activated carbon,ash,zeolites,metal oxides,chitosan,and agri-cultural by-products [28].It is also worth mentioning here that graphene/nanomaterials composites are also considered to be a highly effective adsorbent due to the peculiar properties and large surface area.Particularly,the research about the application of graphene/nanomaterials composites in the adsorption of heavy metal ions is important for environment and human.In this work,SiO 2/graphene composite was prepared via a two-step procedure route that contains the preparation of silica nanoparticles in the presence of graphene oxide solution and the reduction of graphene oxide in the presence of silica nanoparticles.Then,the resulting composite was chosen as an adsorbent toward Pb(II)ion and the adsorption behaviors were investigated in de-tails.Meanwhile,the influence of experimental conditions,includ-ing pH value,ionic strength and contact time,adsorbability,and0021-9797/$-see front matter Ó2011Elsevier Inc.All rights reserved.doi:10.1016/j.jcis.2011.12.023Corresponding author.Fax:+862885412798.E-mail address:lvy@ (Y.Lv).adsorption capacity,was also discussed.Interestingly,the SiO 2/graphene composite was found to be highly effective adsorbent with high selectivity and fast adsorption equilibrium toward Pb(II)ion.2.Materials and methods2.1.Chemical reagents and materialsGraphite powder was of SpecPure grade and was purchased from Tianjin Guangfu Fine Chemical Research Institute.Other reagents were of analytical grade and were used without further purification.Deionized (DI)water from ULUPURE Water Purification System (Chengdu,China)was used to prepare all solutions.Lead nitrate (Pb(NO 3)2,P 99.0%),ethanol,sodium hydroxide (NaOH),hydrazine hydrate (H 2NNH 2ÁH 2O,P 50.06%),and hydrochloric acid (HCl,P 36.46%)were obtained from Chengdu Kelong Chemical Reagent Company (China).Stock standard solution of lead (1000mg L À1)was prepared from analytical grade lead nitrate.2.2.Preparation and characterization of SiO 2/graphene composite The soluble graphene oxide–based sheets were produced by complete exfoliation of graphite oxide as an entry into SiO 2/graph-ene composite.Graphite oxide was synthesized according to the Hummers method through the oxidation of natural graphite pow-der [12].After that,graphite oxide (100mg)was exfoliated in 400mL of distilled alcohol–water (7:1,v/v)solution by ultrasonic treatment for 2h to form a colloidal suspension approximately.Then,the collected colloidal suspension was separated by centrifu-gation at 4000rpm,and the supernatant was obtained in order to prepare the followed composite.The well-known hydrolysis of tet-ramethyl orthosilicate (TEOS)was used for the fabrication of the composite.Briefly,the pH of the reaction mixture was adjusted to 9.00with ammonia solution and then added TEOS (2.1mL)into this dispersion,resulting graphene oxide–containing sol [29].The obtained mixture was stirred magnetically and reduced with hydrazine hydrate (P 50.06%)at 95°C for 24h.was collected through 0.45l m filter and water to remove the excess hydrazine hydrate,thesized composite was dried at 323K overnight 2.3.Characterization and apparatusThe UV–Vis spectra of GO and SiO 2/GO 200–500nm were recorded by U-2910UV–Vis The surface properties and composition of silica nanoparticles were investigated by Fourier IR)spectroscopy using Thermo Nicolet IS10FT-IR KBr pellets in the range 500–4000cm À1.X-ray troscopy (XPS)was performed with a XSAM 800eter (Kratos)using medium resolution and radiation to analyze the surface composition and of products.The binding energies were calibrated tainment carbon (284.8eV).Also,the wide-angle 35mA)powder X-ray diffraction (XRD)using a X’Pert Pro X-ray diffractometer (Philips)tion (k =1.5406Å).The surface morphology of the examined by SEM (Hitachi,S3400).The (BET)surface area and the pore size distribution were measured using N 2adsorption and desorption SI,Quantachrome,USA)at 77K over a relative 0.0955to 0.993.2.4.Batch adsorption experimentBatch adsorption tests were carried out at room temperature (25°C)and used to investigate the effects of various parameters on the adsorption of Pb(II)ion by SiO 2/graphene.For adsorption experiments,3mg of adsorbents was dispersed into a 20mg L À1Pb(II)ion solution (10mL)and was shaken with a magnetic stirrer for 60min to reach equilibrium except kinetic experiments.The SiO 2/graphene solution mixtures were filtered with a 0.45l m fil-ter,and the equilibrium concentrations of Pb(II)ion in the solution were quantified by flame atomic absorption spectroscopy (FAAS,Zeeman GGX-6,China).According to the above procedure,the impact of the pH value,ionic strength,and contact time on adsorp-tion was investigated.The adsorption capacity (q e ,mg g À1)and the adsorption efficiency (E ,%)were calculated according to Eqs.(1)and (2):q e ¼ðC 0ÀC e ÞÁVWð1ÞE ¼C 0ÀC eC 0Â100%ð2Þwhere C 0and C e (mg L À1)are the initial and equilibrium concentra-tions of Pb(II)ion in aqueous phase,and V is the volume of the solu-tion (L ),and W is the mass of dry adsorbent used (g ),respectively.3.Results and discussion 3.1.Characterizations of compositeUV–Vis spectrogram (Fig.S1)shows that GO nanosheets pres-ent a clear characteristic absorption in aqueous solution with a maximum wavelength at 228nm.On the other hand,SiO 2/GO composite exhibits a weak absorption at 226nm,which is due to the assembly of the GO nanosheets.The phenomenon of blueshift of the maximum wavelength is attributed to the change of the environment around the GO nanosheets,which preliminarily indi-cates that SiO 2/GO composite is successfully prepared.Similar 382L.Hao et al./Journal of Colloid and Interface Science 369(2012)381–387the A OH bending vibration of the adsorbed water molecules[29]. This suggests that SiO2nanoparticles are successfully prepared through the above pared with SiO2nanoparticles, the minor and weak peaks are observed at2980and2930cmÀ1, which are attributed to the C A H stretching vibration[33],which indicate the effective attachment of graphene and the successful preparation of SiO2/graphene composite.The surface composition and the element characterization of the composite were analyzed using XPS spectra of composite, which was conducted in the region of0–1100eV.As shown in Fig.2a,there are three elements in the XPS spectra of the compos-ite,namely carbon,oxygen,and silicon,without other elements. The spectra of XPS(Fig.2a)exist the characteristic peaks of Si2s (150eV),Si2p(104.5eV),which is indicative of the formation of the SiO2phase in composite.Moreover,the presence of SiO2can be further confirmed by the O1s XPS peak at532.8eV(Fig.2c), which is regarded as the oxygen species in the SiO2[34,35].In addition,there are at least three types of oxygen species about the O1s peak(Fig.2c),that is,the contribution of the anionic oxy-gen in SiO2at about532.8eV,the oxygen-containing functional groups at around532.3eV,and water at higher binding energies. The C1s XPS spectra,as shown in Fig.2b,contain four components corresponding to carbon atoms in different oxygen-containing functional groups[36]:(a)the non-oxygenated ring C at 284.8eV,(b)the carbon in C A O at285.9eV,(c)the carbonyl car-bon(C@O)at287.0eV,and(d)the carboxylate carbon(O A C@O) at288.2eV.The C1s spectrum of SiO2/graphene shows mainly the nonoxygenated carbon(284.8eV)and the carbon in C A O (285.9eV).Moreover,nonoxygenated carbon is more than the car-bon in C A O,which indicates that deoxygenation has appeared. Meanwhile,XRD was used to further verify the deoxygenation (Supplementary data,Fig.S2).The peak at10.4°corresponding to the diffraction peak of GO was disappeared and the newly obtuse peak at23.0°was observed,which confirm that GO was reduced with hydrazine hydrate and amorphous SiO2nanoparticles were formed[29,32].However,small amount residual oxygenated groups are still left,which are verified by the O1s XPS peaks at 532.3eV(C@O)and533.6eV(C A O)and also indicated that GO has not been completely reduced by hydrazine hydrate.Besides,silica nanoparticles to form a composite in nanoscale.In the images of SiO2/graphene(Fig.3c and d),the layer structure of graphene is well observed at high magnification and SiO2nanoparticles are tightly covered by the corrugated grapheneflakes,which is differ-ent from previous report[30]that graphene nanosheets are immo-bilized onto SiO2nanoparticles through surface assembly.In addition,N2adsorption–desorption isotherms were also em-ployed to investigate the specific surface area and the pore struc-tures of prepared samples(the chemical analysis reveals that the weight percentage of graphene is about12.5wt.%)(Fig.4).The BET surface area and pore volume estimated from Barret–Joyner–Halenda(BJH)analysis of the isotherms were determined to be 252.5m2gÀ1and0.3771cm3gÀ1,respectively.Also,the average of the pore size distribution is2.987nm,which was calculated from the absorption branch by the BJH method.As Fig.4shows, a slight adsorption is observed in the low pressure region(<0.6P/ P0),followed by a sharp adsorption at0.8P/P0,which suggests that this adsorption step occurs on its surface and the interlayer of restacking graphene layers[37].Also,a hysteresis loop can be seen in desorption branch.The shape of adsorption isotherms may be considered to be reversible type V isotherms,which is considered that there is weak interaction between materials and nitrogen. The shape of desorption branch is a typical H3type,indicating that the slit holes in the composite may be formed by the aggregation of various platelike particles.Thus,SiO2/graphene could be a good candidate as a kind of adsorption material.3.2.Adsorption performance3.2.1.Effect of pH on the adsorptionThe pH of the solution usually exerts a great effect on the adsorption of metal ions.According to the solubility-product con-stant of Pb(OH)2(Ksp=1.43Â10À15)and the initial concentration of Pb(II)ion of20mg LÀ1,the pH value of appearance of metal ion hydroxides precipitation is calculated as8.59.In order to investi-gate the effect of pH on the adsorption of Pb(II)ion onto SiO2/ graphene,10mL Pb(II)ion solution with the concentration of 20mg LÀ1was adjusted to a pH range of2.00–7.00with different concentrations of NaOH and HCl solutions,during which noL.Hao et al./Journal of Colloid and Interface Science369(2012)381–387383results in low adsorption.As the pH increased,more binding sites were released and there were less competition of active sites between hydrogen ion and lead(II)ion,resulting in better adsorp-tion behavior.In addition,the surface charge of SiO2/graphene with more negative charge density at higher pH causes more electro-static attractions of Pb(II)ion,which serves as another reason for the better adsorption behavior.3.2.2.Effect of ionic strength on the adsorptionThe different ionic strengths,such as0.001M,0.005M,0.01M, 0.05M,0.1M KNO3,and without KNO3,were chosen to investigate their effect on Pb(II)ion adsorption by SiO2/graphene.Fig.5b shows that Pb(II)ion adsorption decreases with increasing ionic strength.This phenomenon could be attributed to following reasons:(1)the Pb(II)ion forms outer-spherethe adsorbent sites,which favor the adsorptiontration of the competing salt is decreased.adsorption between the adsorbent andmainly of ionic interaction nature;(2)ionicinfluences the activity coefficient of metaltransfer to the composite surfaces[38].3.2.3.Effect of contact time on the adsorptionTime course of Pb(II)ion adsorption ontoexecuted under Pb(II)ion solution with concentrationat pH=6.00and I=0.001M KNO3.Fig.6contact time on the adsorption of Pb(II)composite.It can be seen that the adsorptionsharply,with about95%of total Pb(II)ion10min,then the adsorption reaches equilibriumfast adsorption rate is attributed to the laminatedlarge external surface of SiO2/graphene.Furthertime does not enhance the adsorption percentage2value industrial applications.The kinetics of Pb(II)ion adsorption was determined in order to understand the adsorption behavior of the SiO2/graphene compos-ite.The adsorption data of Pb(II)ion at different time intervals are fit for a pseudo-second-order kinetic model.The calculated curve corresponding to Pb(II)ion sorption was plotted in Fig.6(inset). The kinetic rate equation is expressed asdqtdt¼k2Áðq eÀq tÞ2ð3ÞBy integrating Eq.(3)with the boundary conditions of q t=0at t=0and q t=q t at t=t,the following linear equation can be obtained:tt¼12eþteð4ÞFig.3.SEM image of SiO2(a)and the different magnification of SiO2/graphene composite(b–d). (black)–desorption(red)isotherms and pore sizeV0¼k2Áq2eð5Þwhere q t and q e are the amounts of Pb(II)ion adsorbed at time t and at equilibrium(mg gÀ1),respectively.The k2(g mgÀ1minÀ1)repre-sents the pseudo-second-order rate constant for the kinetic model, which can be obtained by a plot of t/q t against t.V0(mg gÀ1minÀ1) is the initial sorption rate.As shown in Table S1,the comparison be-tween the experimental adsorption capacity(q exp)value and the calculated adsorption capacity(q cal)value shows that q cal value is very close to q exp value for the pseudo-second-order kinetics. Moreover,the adsorbent system can be well described by pseudo-second-order kinetic model,which also is confirmed according to the correlation coefficient value for pseudo-second-order model, equal to1.000,higher than that of pseudo-first-order,suggesting that the adsorption may be the rate-limiting step involving valence forces through sharing or exchange of electrons between the adsor-bent and the adsorbate.3.3.Adsorption isothermsIn addition to adsorption kinetics,we measured the absorption isotherms of Pb(II)ion onto SiO2/graphene to explore the adsorp-tion mechanism much deeply.As shown in Fig.7,at low initial Pb(II)ion concentration,the composite exhibits high adsorption percentage as98.82%.Although the adsorptivity decreases with increasing initial Pb(II)ion concentration,Pb(II)ion adsorption capacity steadily rises.The Langmuir and Freundlich models are the most frequently used models among the abundant isothermal models.The Lang-muir isotherm,which assumes monolayer coverage on adsorbent [39]and no subsequent interaction among adsorbed molecules, is expressed as[40]:1qe¼1qmþ1K LÁq mÁC eThe Freundlich isotherm is derived to model multilayer adsorp-tion on adsorbent.It can be described as[40]:ln qe¼ln K Fþ1nÁln C ewhere q e and C e are the adsorption capacity(mg gÀ1)and the equi-librium concentration of the adsorbate(mg LÀ1),respectively.K L is the constant related to the free energy of adsorption(L mgÀ1),and q m is the maximum adsorption capacity(mg gÀ1).K F and n are the Freundlich constants,which represent the adsorption capacity (mg gÀ1)and the adsorption strength,respectively.The values of q m and K L are calculated from the slope and intercept of the linear plot of1/q e against1/C e.ln K F and1/n can be obtained from the intercept and the slope of the linear plot of ln q e versus ln C e.The adsorption isotherms of Pb(II)ion on the SiO2/graphene com-posite as a function of Pb(II)concentration(pH=6.00,30min adsorption time)are shown in Fig.7(inset),and the Langmuir and Freundlich constants are presented in Table1.The adsorption data(a)and ionic strength(b)for the adsorption percentage and capacity of Pb(II)ion at room temperature(25°C):adsorption time, concentration,20mg LÀ1;and ionic strength,0.001M KNO3for a;pH,6.00for b.arefit for Langmuir model,and it shows the maximum adsorption capacity of113.6mg gÀ1for the SiO2/graphene composite.Also, the higher correlation coefficients indicate that the Langmuir model fits the adsorption data better than the Freundlich model.In other words,this adsorption process took place by monolayer on the homogeneous sites of the surface of SiO2/graphene.The adsorption capacities of other absorbents toward Pb(II)ion are listed in Table S2,and the comparative results show that the adsorption capacity of SiO2/graphene is higher.Therefore,it can be concluded that SiO2/graphene has much superior adsorption capacity for removing Pb(II)ion.3.4.Selective adsorption experimentThere are mainly six different heavy metals in the waste water: Cu2+,Pb2+,Ni2+,Co2+,Cd2+,and Cr3+.We chose a mixed solution of metal ions,which was prepared by diluting1000mg LÀ1of Cu2+, Pb2+,Ni2+,Cd2+,Co2+,and Cr3+to20mg LÀ1in25mLflask volumet-ric for a selective adsorption experiment;6.0mg adsorbent was dispersed in20mL of solution and the mixture was stirred for 30min at room temperature.In order to avoid to produce Cu(OH)2 (pH=5.92)and Cr(OH)3(pH=5.07)at the optimum condition (pH=6.00),the pH value of solution was chosen as4.80,at which the adsorption efficiency of Pb(II)ion would be little lower.Under this condition,the uptake of Pb(II)ion from this mixed metal ion solution on the SiO2/graphene composite is as high as84.23%, while other ions show only slight/negligible adsorption.The exper-iment data demonstrate highly selective adsorption of Pb(II)ion on the SiO2/graphene composite.3.5.Adsorption mechanismGenerally speaking,the adsorption of metal ions is based on the three adsorption mechanisms:electrostatic interactions,ion ex-change,and complex formation[41].In our study,the pH value of the solution increased after adsorption of Pb(II)ion(Table2), and the adsorption efficiency of Pb(II)ion increased with increas-ing the pH value until the optimum pH,which is in accordance with the related literature[27].As we all know,graphene sheets, containing delocalized p electrons,and lead ion/hydrogen ion act as electron donor and acceptor,respectively,which can form the electron donor–acceptor complexes.In this system,the complex is formed by a coordination bond(or dative bond or dipolar bond) between the unshared electron pair of the composites and an elec-tron-deficient atom of lead ion and hydrogen ion.So,it suggests that lead ion and hydrogen ion simultaneously adsorbed onto graphene and form composites,and results in an increase in the pH value.This phenomenon indicates that ion exchange is not the main cause.For our study,the surface charge is regarded as negative at high pH,which provides the ability of binding cations through electrostatic interaction.Besides,according to the previ-ous report,the basic sites as C p electrons on graphene sheets are considered as the important adsorption sites[42].Conse-quently,electrostatic interaction between Pb(II)cations and nega-tive surface charge and/or C p electrons of the composite is regarded as the main interaction for the adsorption of Pb(II)ion onto the composite.In addition,the specific surface area (252.5m2gÀ1)according to BET measure is another course,which provides more active sites for Pb(II)ion adsorption.However,re-search is needed for the clear mechanism in further investigations.4.ConclusionsIn summary,the SiO2/graphene composite was synthesized via a facile,fast,and low-cost process and further was developed to be highly efficient adsorbent for Pb(II)ion in aqueous solution.The SiO2/graphene composite reduces the serious stacking of graphene sheets and prevents the agglomeration of SiO2nanoparticles,and also produces a high surface area,which enables the composite to show high binding capability and excellent adsorption proper-ties for Pb(II)ion.This adsorbent is stable,low-cost,and environ-mentally friendly and shows potential application in the removal of Pb(II)ion from agricultural and industrial waste water.In addi-tion,successful preparation of SiO2/graphene composite was very helpful to understand the fundamental properties of graphene-based composites and some practical applications.AcknowledgmentsThis work was supported by the National Nature Science Foun-dation of China(21075084)and the Sichuan Youth Science&Tech-nology Foundation(No.2009-18-409).The authors also would like to show gratitude for Dr.Jiqiu Wen and Dr.Hong Chen of Analytical &Testing Center at Sichuan University for their assistance in the XRD and XPS analysis.Appendix A.Supplementary materialSupplementary data associated with this article can be found,in the online version,at 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微反应技术硝化合成硝酸异辛酯
2392 当 代 化 工 2020年11月图9 IE-H1离子筛的循环稳定性Fig.9 Cycle stability of IE-H1 ion sieve3 结 论1）采用溶剂热法制备，在800 ℃下煅烧，添加1 g F127的Li4Ti5O12离子筛前驱体具有尖晶石结构，且结晶度高，晶型完整，表面形貌呈均匀的球状，颗粒尺寸均匀；通过测试得到用0.1 mol·L-1的盐酸对其酸改，酸改后晶型及表面形貌不发生变化，酸改率达88.60%。
2）酸改得到的IE-H1离子筛在25 ℃、pH=9的溶液环境下对Li+的饱和交换容量高达 6.648 0 mmol·g-1，在不同离子溶液中以及混合离子溶液中均表现出良好的选择吸附性能，可用作锂离子吸附剂。
3）经过5次循环吸脱附试验后，IE-H1离子筛对Li+的吸附容量为6.632 4 mmol·g-1，离子筛的稳定性较好，是盐湖卤水提锂吸附剂的极佳候选者。
参考文献：［1］林大泽.锂的用途及其资源开发[J].中国安全科学学报，2004，14（9）：72-76.［2］王登红，孙艳，刘喜方，等. 锂能源金属矿产深部探测技术方法与找矿方向[J].中国地质调查，2018，5（1）：1-9.［3］AN J W, KANG D J, TRAN K T, et al. Recovery of lithium from Uyuni salar brine[J].Hydrometallurgy,2012,117-118: 64-70.［4］BROUSSELY M, ARCHDALE G. Li-ion batteries and portable power source prospects for the next 5–10 years[J].Journal of Power Sources, 2004, 136(2): 386-394.［5］CHAE J S, JO M R, KIM Y I, et al. Kinetic favorability of Ru-doped LiNi0.5Mn1.5O4 for high-power lithium-ion batteries[J].Journal of Industrial and Engineering Chemistry, 2015, 21: 731-735.［6］王可珍，李芳，勾路路.锂离子正极三元材料的制备与改性研究[J].当代化工，2014，43（12）：2526-2528.［7］邓小川，朱朝梁，史一飞，等.青海盐湖锂资源开发现状及对提锂产业发展建议 [J].盐湖研究，2018， 26（4）：11-18.［8］袁俊生，纪志永，陈建新.海水化学资源利用技术的进展[J].化学工业与工程，2010，27（2）：110-116.［9］贾文婷，郭梁辉.罗布泊盐湖卤水中锂吸附率的提高[J].当代化工，2017，46（12）：2477-2480.［10］辛文萍，靳彩颖，王青青，等. 盐湖卤水提锂吸附剂合成进展[J].山东化工，2016，45（17）：58-62.［11］高峰，郑绵平，乜贞，等.盐湖卤水锂资源及其开发进展[J].地球学报，2011，32（4）：483-492.［12］CHEN L, XU X, SONG J, et al. Microwave assisted hydrothermal synthesis of MnO2·0.5H2O ion-sieve for lithium ion selectiveadsorption[J].Separation Science and Technology, 2015, 51(5):874-882.［13］BAJESTANI M B, MOHEB A, MASIGOL M. Simultaneous optimization of adsorption capacity and stability of hydrothermallysynthesized spinel ion sieve composite adsorbents for selectiveremoval of lithium from aqueous solutions[J].Industrial&Engineering Chemistry Research, 2019, 58(27): 12207-12215. ［14］周惠敏，袁俊生，张亮，等.水热法合成铬掺杂尖晶石型锂离子筛及其锂吸附性能 [J].功能材料，2011, 42（Z4）: 621-624. ［15］綦鹏飞，朱桂茹，王铎，等.锂离子筛的制备及其吸附性能研究[J].功能材料，2010，41（3）：432-435.［16］XIAO J, NIE X, SUN S, et al.Lithium ion adsorption-desorption properties on spinel Li4Mn5O12and pH-dependent ion-exchangemodel[J].Advanced Powder Technology, 2015, 26(2): 589-594. ［17］董殿权，王永顺，房超.多孔掺杂型钛系离子筛的制备及吸附性能[J].化工学报，2016，68（7）：2812-2817.中科院大连化学物理研究所科研成果介绍微反应技术硝化合成硝酸异辛酯负责人：陈光文 联络人：陈光文电话：0411-******** 传真：0411-******** E-mail：**************.cn学科领域：精细化工 项目阶段：中试放大项目简介及应用领域异辛醇混酸硝化生产的硝酸异辛酯作为柴油十六烷值改进剂，对柴油油品升级起着重要作用。
镁离子电池研究进展
2020年第23期广东化工第47卷总第433期 · 81 ·镁离子电池研究进展马超，李茂龙，丁一鸣，贺畅，曹志翔，鲍克燕(江苏理工学院化学与环境工程学院，江苏常州213001)[摘要]镁电池因具有比锂离子电池更高的安全性和更低廉的价格而受到越来越多的关注，近些年研究者们针对高性能镁电解质的开发、嵌镁正极材料设计等方面投入了大量研究，许多技术壁垒也不断被突破。
本文对镁电池的研究成果进行了调研并综述。
[关键词]镁离子电池；正极材料；电解液[中图分类号]TQ [文献标识码]A [文章编号]1007-1865(2020)23-0081-01Research Progress of Magnesium Ion BatteriesMa Chao, Li Maolong, Ding Yiming, He Chang, Cao Zhixiang, Bao Keyan(School of Chemical and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China) Abstract: Magnesium batteries have attracted more and more attention because of their higher safety and lower price than lithium ion batteries. In recent years, researchers have invested a lot of research in the development of high-performance magnesium electrolytes, positive electrode materials, and many technical barriers have been constantly broken. In this paper, the research magnesium ion batteries are investigated and reviewed.Key words: magnesium ion batteries；positive electrode materials；the electrolyte锂离子电池具有多种优势，但是锂负极枝晶的形成会导致安全隐患，此外，地球上有限的锂资源也成为锂离子电池制造行业关注的问题。
北大考研-环境科学与工程学院研究生导师简介-叶正芳
爱考机构 中国高端考研第一品牌（保过 保录 限额）
2010.1-2010.12 南水北调东线治污新理念与成效研究 国务院南水北调办 项目负责人 25
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高等学校科学技术进步奖 固定化微生物处理高氨氮废水的研究 一等
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纳米复合材料最新科技文献
ResearchpaperRemoval of crystal violet by clay/PNIPAm nanocomposite hydrogels with various clay contentsQingsong Zhang ⁎,Tingting Zhang,Tao He,Li ChenState Key Laboratory of Hollow Fiber Membrane Materials and Processes,School of Materials Science and Engineering,Tianjin Polytechnic University,Tianjin 300387,Chinaa b s t r a c ta r t i c l e i n f o Article history:Received 15August 2012Received in revised form 3January 2014Accepted 4January 2014Available online 31January 2014Keywords:Clay polymer nanocomposite hydrogel Nanoclay Crystal violet Adsorption Dye removalThe clay/poly(N -isopropylacrylamide)(PNIPAm)nanocomposite (CPN)hydrogels,using lithium magnesium silicate hydrate (LMSH)as a clay mineral physical cross-linker,with the mass ratio of NIPAm/LMSH ranging from 5to 30wt.%were prepared to remove crystal violet (CV)from aqueous solution.Morphology and temperature-sensitivity of hydrogels were investigated by SEM and DSC.Adsorption capacity and kinetic under different times,pH values and concentrations were evaluated by using UV/vis spectroscopy.The pore sizes of CPN hydrogels range from 30to 50μm,and volume phase transition temperature (VPTT)were 33–36°C.The adsorption capacity (Q t )of CV onto CPN hydrogels at 25°C increased quickly at initial 12h,with a maximum value of 4.71mg/g.At 37°C,the Q t values are not more than 2mg/g.The Q t values of CPN hydrogels increase 2–4times when CV concentration was added from 10to 30mg/L,and increase 1–1.5times as pH value increases from 3.0to 8.9.Crown Copyright ©2014Published by Elsevier B.V.All rights reserved.1.IntroductionMany industries producing food,plastics,textile and cosmetics use dye to color their products (Jeon et al.,2008).As a result,dye contami-nation has become a serious environmental and social problem due to increasing damage to natural ecosystems when they are discarded into wastewater.As a typical cationic dye,crystal violet (CV)belongs to triphenylmethane group,and is widely applied in coloring paper,temporary hair colorant,dyeing cottons,and wools.CV is harmful by inhalation,ingestion and skin contact,and has also been found to cause cancer and severe eye irritation to human beings (Lin et al.,2011;Saeed et al.,2010).It is very essential to remove CV from industrial ef fluents before it is discarded into wastewater.The adsorption of polymeric hydrogels has been found to be severed as an optimum adsorbing material for dye wastewater treatment in terms of economic feasibility,adsorption –regeneration,simplicity of design,ease of operation and insensitivity to toxic substances (Li,2010;Shirasth et al.,2011).Haraguchi and Takehisa (2002)and Haraguchi et al.(2007)developed a special type of inorganic –organic clay/poly(N -isopropylacrylamide)(PNIPAm)nanocomposite hydrogel by using Laponite XLG (Lap)as phys-ical cross-linker in the absence of any chemical cross-linker.The exfoliat-ed Lap particles acted as multifunctional cross-linker,and the polymer chains are anchored to the particles and entangled to form a network (Haraguchi et al.,2005).Previously,Zhang et al.(2009)have shown that a novel nanoclay mineral coming from China mainland was found to be a best candidate than natural hectorite to prepare clay/PNIPAmnanocomposite hydrogel.In addition,it was also found that PNIPAm hydrogel cross-linked by lithium magnesium silicate hydrate(LMSH)is the best choice for removing CV dye compared to clay/polyacrylamide (PAM)nanocomposite hydrogels (Zhang et al.,2011).It is known that hydrogels often have porous structure networks and allow solute diffusion through the hydrogel structure (Li and Liu,2008).Moreover,clay can be used as adsorbents due to their high speci fic sur-face area,chemical and mechanical stabilities,and a variety of surface and structural properties (Liu and Zhang,2007).Together with ionic functional groups of hydrogels,inorganic –organic nanocomposite hydrogels can absorb and trap ionic dyes like CV.In this work,the clay/PNIPAm nanocomposite hydrogels with various LMSH contents were prepared via in-situ free radical polymerization.The morphology and thermal-responsibility of resulting hydrogels were investigated by scanning electronic microscopy (SEM)and dif-ferential scanning calorimetry (DSC).The appearance after removing CV,the adsorption characteristics under different times,temperatures,pH values,and concentrations of dye CV onto clay/PNIPAm nanocom-posite hydrogels were investigated by Ultra-Violet/Visible (UV/Vis)Spectrophotometry.2.Experiments2.1.Synthesis of clay polymer nanocomposite (CPN)hydrogelsAccording to previous reports (Zhang et al.,2009),the clay/PNIPAm nanocomposite hydrogels were prepared by in-situ free radical polymerization of monomer N -Isopropylacrylamide (NIPAm)in the presence of LMSH.In this work,LMSH content varied from 0.05to 0.30g.The resulting clay/PNIPAm nanocomposite hydrogel samplesApplied Clay Science 90(2014)1–5⁎Corresponding author.Tel./fax:+862283955362.E-mail address:zqs8011@ (Q.Zhang).0169-1317/$–see front matter.Crown Copyright ©2014Published by Elsevier B.V.All rights reserved./10.1016/j.clay.2014.01.003Contents lists available at ScienceDirectApplied Clay Sciencej o u r n a l h o m e p a g e :w ww.e l s e v i e r.c o m/l o c a t e /c l a ywere simply named as CPNX.In the present study,X means the mass ratio of LMSH and NIPAm.For example,the hydrogel synthesized by 0.1g LMSH/1.0g NIPAm/10g H 2O is expressed as CPN10.When reaction was finished,all samples were cut into disk-shape pieces,and immersed in an excess of deionized water for 4days to remove impurities by changing water.Chemical formula of cationic dye CV and NIPAm can be found from Table 1.2.2.Characterization2.2.1.Scanning electron microscopy (SEM)The swollen hydrogels in deionized water were frozen to −40°C,and then fractured and freeze-dried.The morphology of the fractured specimens was observed on a JEOL JSM-5600LV SEM after sputter coating with gold under vacuum.2.2.2.Adsorption kineticsFor the adsorption kinetics,the adsorption of CV was carried out onto CPN hydrogels.The CPN hydrogels was immersed in 50mL of 10mg/L CV solution.The test temperature was 25°C.During the adsorption,the CV solution was withdrawn from the adsorption system at indicated times for the analysis of CV concentrations by using UV/vis spectrophotometer at λmax (nm)=591nm.The amounts of CV adsorbed on the hydrogel at time t,q t (mg/g dried hydrogel),were determined according to Eq.(1):q t ¼C 0−C t ðÞVð1Þwhere,V is the solution volume (mL),m is the mass of dried hydrogel (g),C 0and C t is the dye concentration at initial and indicated time (mg/mL),respectively.For the effects of pH on CV adsorption behavior,the CPN hydrogels were placed in sealed bottles containing known initial concentrations of the dye at a certain pH,and allowed to equilibrate for 3days at 25°C.The equilibrated solutions were sampled and analyzed for the dye concentration as described above.2.2.3.Differential scanning calorimeter (DSC)analysisThe DSC measurements of the swollen samples were carried out on a DSC-7differential scanning calorimeter (Perkin-Elmer Inc.,USA)under a nitrogen atmosphere,at a heating rate of 2°C·min −1from 15to 50°C.Deionized water was used as the reference in the DSC measurement.3.Results and discussion3.1.Morphology and adsorption appearance of CPN hydrogelsHaraguchi et al.(2005)has pointed out that hectorite with a layered structure,could be exfoliated into single layers when dispersed intoaqueous solution under stirring,acting as multifunctional cross-linker through ionic or polar interaction.For PNIPAm molecule chains,it is considered that they were attached to the hectorite layers forming a network structure.Zhang et al.(2009)have reported that LMSH plays ionic or polar interaction similar with hectorite.To avoid the collapse of pore shape,the disk hydrogel samples were freeze-dried at −60°C.The interior morphologies of CPN hydrogels,with a magni fication of ×800,are shown in Fig.1.It is seen that all CPN hydrogels exhibit homogeneous and well-proportioned open pores'structure.The thickness of walls between pores are only 1–2μm.The pore sizes range from 30to 50μm,which may be favorable to absorb CV molecules.In addition,with increasing nanoclay content,the pore number increased while pore diameter decreased slightly.To examine the adsorption of CV from appearance,the disk shape hydrogel sample was placed in aqueous solutions of CV (10mg/L)for two days at 25°C.The changes of color solutions of CV and CPN10hydrogel before and after adsorption are shown in Fig.2.It can be seen from Fig.2(A)and (C)that the CV solution shows purple while CPN10hydrogel presents transparent before adsorption.Two days later,as shown in Fig.2(B)and (D),the aqueous solution of CV contain-ing CPN10hydrogel showed colorlessness,but the CPN10hydrogel turned violet from transparent.It is interesting to note that the absorbed CPN10hydrogel still keeps purple no matter how long it is put into deionized water.This phenomenon con firmed that the CPN hydrogels could absorb CV completely from the cationic CV solution within a given time.3.2.Time dependence of CV adsorption onto CPN hydrogelsTo analyze time dependence of cationic CV adsorption amount at different times,the time pro file of CV adsorption onto CPN hydrogels at 25°C was made,as shown in Fig.3.It can be seen that,with time going on,the adsorption capacity (Q t )increased quickly at initial 12h.The Q t values of CPN05,CPN10,CPN15and CPN20hydrogels are 2.74,4.23,4.32and 4.71mg/g at t =12h.As mentioned in Fig.1,homoge-neous and well-proportioned open pores'structure of CPN hydrogels could contain a large quantity of CV molecules.In addition,the LMSH surfaces have negative charges and the LMSH edges have small localized positive charges generated by absorption of ions like Li +,Na +and Mg 2+.Therefore,a kind of positive/negative charge attraction exists between CV molecules and LMSH.Our recent work has proved that pure LMSH can also be used as adsorbent for CV.Consequently,Q t value of CPN hydrogels increases with the addition of LMSH content at 12h.It is also interesting to note that Q t value,compared to that at t =12h,increased 1.6–1.8times when t =50h.In other words,the adsorption rate of CV by CPN hydrogel is very slow in spite of high adsorption amount.3.3.Thermal-responsibility of the CPN hydrogelsTo illustrate the phase transition behavior of CPN hydrogels,the DSC thermograms are displayed in Fig.4.It is seen that the all CPN hydrogel samples exhibit VPTT between 33and 36°C,higher than the results (~32°C)reported by Zhang et al.(2012).The reason can be ascribed to the difference of heating rate and instrument measurement.With increasing LMSH content,it is clear to note that the VPTT value increased.The larger LMSH content would lead to high cross-linking degree.It is natural that high temperature is needed to break hydrogen bonding so that water molecules can be released from CPN hydrogel matrix.Time pro files of CV onto CPN hydrogels at 37°C are shown in Fig.5.In comparison with Fig.3,the Q t values of CPN hydrogels are not more than 2mg/g at 37°C,much lower than those at 25°C.Furthermore,the adsorption capacity has reach equilibrium at 24h.The reason can be ascribed to swelling and temperature-sensitivity of PNIPAm hydrogels.The CPN hydrogels present swollen state at 25°C,lower than VPTT,and PNIPAm chains are free to stretch.But when temperature is higher thanTable 1Chemical formula of cationic dye CV and monomerNIPAm.2Q.Zhang et al./Applied Clay Science 90(2014)1–5VPTT,at 37°C,the CPN hydrogels turn globule-to-coil transition and shrunk,showing lower adsorption capacity.3.4.Effect of CV concentration on dye adsorptionTo investigate the adsorption property of CPN hydrogels at high CV concentration,the time pro file of CV adsorption onto CPNhydrogelsFig.1.SEM images of CPN hydrogels with various nanoclaycontents.Fig.2.Photographs of CV solution (A)before adsorption and (B)after adsorption and CPN10hydrogel (C)before adsorption of dye and (D)after adsorption of dye (temperature 25°C;pH of solution 7.4;initial concentration of the dye 10mg/L).Fig.3.Time pro files of CV absorption onto CPN hydrogels at 25°C.3Q.Zhang et al./Applied Clay Science 90(2014)1–5under 30mg/L CV solution at 25°C was shown in Fig.6.In comparison with the curves of Fig.3,the Q t values of CV onto CPN hydrogels increased 2–4times.For example,when temp.=25°C and time =12h,Q t values of CPN30hydrogel at 30mg/L are 11.2mg/g,while only 4.71mg/g at 10mg/L.It means that CPN hydrogels could absorb high concentrated CV solution.After cutting freeze-dried CPN hydrogels absorbing CV into two pieces,only outer surface presents purple.In other words,CPN hydrogels have large adsorption capacity thanks to larger pore size of CPN hydrogels and charge interaction of LMSH with cationic dye CV.Similar with Fig.3,with increasing LMSH content,adsorption amount of CPN hydrogels increases.It also can be seen that,as the mass ratios of LMSH/NIPAm exceed 10wt.%,the Q t values of CPN10,CPN15and CPN30only present a slight change.Although adsorption amount of LMSH content increased,the adsorption amount of CPN hydrogels resulting from lower swelling ratios at high cross-linking degree decreased.Therefore,the resulting adsorption interaction between CPN10,CPN15,CPN30hydrogels and CV is almost the same.The curves of Q t of CV onto the CPN10hydrogel under different CV concentrations as a function of time are shown in Fig.7.With increasing time from 0to 14h,the Q t values increase quickly.After 44h,the Q tvalues keep almost the same.With increasing CV concentration from 10to 30mg/L,the adsorption amounts of CPN10hydrogel increase sharply.At t =14h,the Q t values of CV onto the CPN10hydrogel under 10,15and 30mg/L,are 4.2,6.1and 12.9mg/g,respectively.At t =44h,the Q t values of CV onto the CPN10hydrogel under 10,15and 30mg/L,are 5.8,8.7and 17.8mg/g,respectively.This result is same with that of Fig.5.3.5.Effect of pH on dye adsorptionThe purple color would fade if CV was put into alkaline conditions.Then,it is natural to study the effect of pH on CV dye adsorption kinetics onto CPN hydrogels under acid conditions.Here,CPN15hydrogel was served as a typical example to evaluate the effect of pH on CV adsorption capacity.The CV adsorption experiments were carried out in solutions having pH values between 3and 9.The effect of pH variations (3.0,4.5and 8.9)on CV adsorption onto CPN15hydrogel from the aqueous solution,for initial CV concentration of 10mg/L,is shown in Fig.8.With increasing pH value from 3.0to 8.9,the amount of CV adsorbed on the CPN15hydrogel increases.At t =37h,the Q t values ofCVFig.4.DSC thermograms for swollen CPNhydrogels.Fig.5.Time pro files of CV absorption onto CPN hydrogels at 37°C.Fig.6.Time pro file of CV adsorption onto CPN hydrogels under 30mg/L CV solution at 25°C.Fig.7.Curves of Q t of CV onto the CPN10hydrogel under different CV concentrations as a function of time.4Q.Zhang et al./Applied Clay Science 90(2014)1–5onto the CPN15hydrogel at pH =3.0,4.5and 8.9,are 5.1,5.8and 6.7mg/g,respectively.At t =85h,the Q t values of CV onto the CPN15hydrogel at pH =3.0,4.5and 8.9,are 5.5,6.9and 7.6mg/g,respectively.This phenomenon can be explained by considering the following two reasons.At lower pH,on the one hand,the CPN hydrogel was in a collapsed status because of the existence of amide groups of the polymer chains and hydrophobic interaction.On the other hand,an aggregated microstructure of house of card will be formed because of charge interaction between negative charge of LMSH surface and H +.As a result,the interaction between CV molecules and LMSH,PNIPAm chains will decrease greatly,leading to lower adsorption at lower pH.On the contrary,at high pH,on the one hand,positive/negative charge attraction between CV and LMSH will accelerate the adsorption.On the other hand,swollen CPN hydrogels provide rapid access tunnel for CV molecules to enter the inner of CPN hydrogel matrix.By the both effection,the adsorbed amount of CV by CPN hydrogel increases.4.ConclusionsThe clay/PNIPAm nanocomposite (CPN)hydrogel with various LMSH contents were prepared,and are ef ficient adsorbent for CV.The pore sizes of hydrogels range from 30to 50μm,which is favorable for CV adsorption.The Q t values of CPN05,CPN10,CPN15and CPN20hydrogels are 2.74,4.23,4.32and 4.71mg/g at t =12h and T =25°C,while is only 1.2and 1.8mg/g for CPN05and CPN30at 37°C.The Q t values of CPN hydrogel increase 2–4times when CV concentra-tion was added from 10to 30mg/L,and increase 1–1.5times as pH value increases from 3.0to 8.9.AcknowledgmentsGreat thanks to the National Nature Science Foundation of China (21104058,31200719&21174103),and the grant from the Applied Basic Research and Advanced Technology Programs of Science and Technology Commission Foundation of Tianjin (12JCQNJC01400&12JCQNJC08600)for financial support.ReferencesHaraguchi,K.,Takehisa,T.,2002.Nanocomposite hydrogels:a unique organic –inorganicnetwork structure with extraordinary mechanical,optical,and swelling/de-swelling properties.Adv.Mater.14(16),1120–1124.Haraguchi,K.,Li,H.J.,Matsuda,K.,Takehisa,T.,Elliott,Eric,2005.Mechanism of formingorganic/inorganic network structures during in-situ free-radical polymerization in PNIPA-clay nanocomposite hydrogels.Macromolecules 38(8),3482–3490.Haraguchi,K.,Li,H.J.,Song,L.,Murata,K.,2007.Tunable optical and swelling/deswellingproperties associated with control of the coil-to-globule transition of poly(N -isopropylacrylamide)in polymer-clay nanocomposite gels.Macromolecules 40(19),6973–6980.Jeon,Y.S.,Lei,J.,Kim,J.H.,2008.Dye adsorption characteristics of alginate/polyaspartatehydrogels.J.Ind.Eng.Chem.14,726–731.Li,S.F.,2010.Removal of crystal violet from aqueous solution by sorption into semi-interpenetrated networks hydrogels constituted of poly(acrylic acid-acrylamide-methacrylate)and amylase.Bioresource Technol.101(7),2197–2202.Li,S.,Liu,X.,2008.Synthesis,characterization and evaluation of semi-IPN hydrogelsconsisted of poly(methacrylic acid)and guar gum for colon-speci fic drug delivery.Polym.Adv.Technol.19,371–376.Lin,Y.,He,X.,Han,G.,Tian,Q.,Hu,W.,2011.Removal of crystal violet from aqueoussolution using powdered mycelial biomass of Ceriporia lacerata P2.J.Environ.Sci.23(12),2055–2062.Liu,P.,Zhang,L.X.,2007.Adsorption of dyes from aqueous solutions or suspensions withclay nano-adsorbents.Sep.Purif.Technol.58(1),32–39.Saeed,A.,Sharif,M.,Iqbal,M.,2010.Application potential of grapefruit peel as dyesorbent:kinetics,equilibrium and mechanism of crystal violet adsorption.Bioresource Technol.179(1–3),564–572.Shirsath,S.R.,Hage,A.P.,Zhou,M.,Sonawane,S.H.,Ashokkumar,M.,2011.Ultrasoundassisted preparation of nanoclay Bentonite-FeCo nanocomposite hybrid hydrogel:a potential responsive sorbent for removal of organic pollutant from water.Desalination 281,429–437.Zhang,Q.S.,Li,X.W.,Zhao,Y.P.,Chen,L.,2009.Preparation and performance of nanocom-posite hydrogels based on different clay.Appl.Clay Sci.46(4),346–350.Zhang,Q.S.,Peng,Z.,Zhao,Y.P.,Chen,L.,Ma,J.,2011.Adsorption characteristics of crystalviolet dye by different types of hydrogels.J.Mater.Engin.12,20–24.Zhang,Q.S.,Zhao,Y.P.,Chen,L.,2012.Preparation of hydrogels with rapid thermalresponse using liquid crystallite as template.Mater.Technol.27(1),127–129.Fig.8.Effect of the pH values on adsorption of CPN15hydrogel for CV at 25°C.5Q.Zhang et al./Applied Clay Science 90(2014)1–5。
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ＫＯＮＧ Ｘｉａｎｇ—ｆｅｎｇ（孔祥峰） ， 一，ＹＡＮＧ Ｂｉｎ（杨斌） ，ＸＩＯＮＧ Ｈｅｎｇ（￣恒） ，ＺＨＯＵ Ｙａｎｇ（周阳） 一， ＸＵＥ Ｓｈｅｎｇ．ｇｕｏ（￣Ｎ） ，ｘｕ Ｂａｏ．ｑｉａＩｌｇ（徐宝强） 一，ＷＡＮＧ Ｓｈｉ．ｘｉｎｇ（王世兴）
１．Ｎａｔｉｏｎａｌ Ｅｎｇｉｎｅｅｒｉｎｇ Ｌａｂｏｒａｔｏｒｙ ｆｏｒ Ｖａｃｕｕｍ Ｍｅｔａｌｌｕｒｇｙ（Ｋｕｎｍｉｎｇ Ｕｎｉｖｅｒｓｉｔｙ ｏｆ Ｓｃｉｅｎｃｅ ａｎｄ Ｔｅｃｈｎｏｌｏｇｙ）， Ｋｕｎｍｉｎｇ ６５００９３，Ｃｈｉｎａ； ２．Ｓｃｈｏｏｌ ｏｆＭｅｔａｌｌｕｒｇｙ ａｎｄ Ｅｎｖｉｒｏｎｍｅｎｔ，Ｃｅｎｔｒａｌ Ｓｏｕｔｈ Ｕｎｉｖｅｒｓｉｔｙ，Ｃｈａｎｇｓｈａ ４１００８３，Ｃｈｉｎａ； ３．Ｓｔａｔｅ Ｋｅｙ Ｌａｂｏｒａｔｏｒｙ ｏｆ Ｃｏｍｐｌｅｘ Ｎｏｎｆｅｒｒｏｕｓ Ｍｅｔａｌ Ｒｅｓｏｕｒｃｅｓ Ｃｌｅａｒ Ｕｔｉｌｉｚａｔｉｏｎ，Ｋｕｎｍｉｎｇ ６５００９３，Ｃｈｉｎａ； ４．Ｙｕｎｎａｎ Ｉｎｓｔｉｔｕｔｅ ｏｆＰｒｏｄｕｃｔ Ｑｕａｌｉｔｙ Ｓｕｐｅｒｖｉｓｉｏｎ ａｎｄ Ｉｎｓｐｅｃｔｉｏｎ，Ｋｕｎｍｉｎｇ ６５０２２３，Ｃｈｉｎａ
◎Ｃｅｎｔｒａｌ Ｓｏｕｔｈ Ｕｎｉｖｅｒｓｉｔｙ Ｐｒｅｓｓ ａｎｄ Ｓｐｒｉｎｇｅｒ－Ｖｅｒｌａｇ Ｂｅｒｌｉｎ Ｈｅｉｄｅｌｂｅｒｇ ２０ １４
Ａｂｓｔｒａｃｔ：Ｔｈｅ ｉｎｄｕｓｔｒｉａｌ ｓｉｌｉｃａ ｆｕｍｅ ｐｒｅｔｒｅａｔｅｄ ｂｙ ｎｉｔｒｉｃ ａｃｉｄ ａｔ ８０。Ｃ ｗａｓ ｒｅ—ｕｓｅｄ ｉｎ ｔｈｉｓ ｗｏｒｋ．Ｔｈｅｎ．ｔｈｅ ｏｂｔａｉｎｅｄ ｓｉｌｉｃａ ｎａｎｏｐａｒｔｉｃｌｅｓ ｗｅｒｅ ｓｕｒｆａｃｅ ｆｕｎｃｔｉｏｎａｌｉｚｅｄ ｂｙ ｓｉｌａｎｅ ｃｏｕｐｌｉｎｇ ａｇｅｎｔｓ，ｓｕｃｈ ａｓ（３一Ｍｅｒｅａｐｔｏｐｒｏｐｙ１）ｔｒｉｅｔｈｏｘｙｓｉｌａｎｅ（ＭＰＴＥＳ）ａｎｄ ｆ３．Ａｍｉｎｃｐｒｏｐｙ１）ｔｒｉｔｈｏｘｙｓｉｌａｎｅ（ＡＰＴＥＳ）． Ｓｏｍｅ ｆｕｒｔｈｅｒ ｍｏｄｉｆｉｃａｔｉｏｎｓ ｗｅｒｅ ｓｔｕｄｉｅｄ ｂｙ ｃｈｌｏｒｏａｃｅｅｔｙ１ ｃｈｏｒｉｄｅ ａｎｄ １，８－Ｄｉａｍｉｎｏａｐｈａｌｅｎｅ ｆｏｒ ａｍｉｎｏ ｍｏｄｉｆｉｅｄ ｓｉｌｉｃａ．Ｔｈｅ ｓｕｒｆａｃｅ ｆｕｎｃｔｉｏｎａｌｉｚｅｄ ｓｉｌｉｃａ ｎａｎｏｐａｒｔｉｃｌｅｓ ｗｅｒｅ ｃｈａｒａｃｔｅｒｉｚｅｄ ｂｙ Ｆｏｕｒｉｅｒ ｔｒａｎｓｆｏｒｉｎ ｉｎｆｒａｒｅｄ（ＦＩ－ＩＲ１ ａｎｄ Ｘ．ｒａｙ ｐｈｏｔｏｅｌｅｃｔｒｏｎ ｓｐｅｃｔｒｏｓｃｏｐｙ（ｘＰＳ）．Ｔｈｅ ｐｒｅｐａｒｅｄ ａｄｓｏｒｂｅｎｔ ｏｆ ｓｕｒｆａｃｅ ｆｕｎｃｔｉｏｎａｌｉｚｅｄ ｓｉｌｉｃａ ｎａｎｏｐａｒｔｉｃｌｅｓ ｗｉｍ ｄｉｆｒｅｒｅｎｔｉａｌ ｆｕｎｃｔｉｏｎ ｇｒｏｕｐｓ ｗｅｒｅ ｉｎｖｅｓｔｉｇａｔｅｄ ｉｎ ｔｈｅ ｓｅｌｅｃｔｉｖｅ ａｄｓｏｒｐｔｉｏｎ ａｂｏｕｔ Ｐｂ ．Ｃｕ ，Ｈｇ ．Ｃｄ ａｎｄ Ｚｎ２ ｉｏｎｓ ｉｎ ａｑｕｅｏｕｓ ｓｏｌｕｔｉｏｎｓ．Ｔｈｅ ｒｅｓｕｌｔｓ ｓｈｏｗ ｔｈａｔ ｔｈｅ ｆ３一Ｍｅｒｃａｐｔｏｐｒｏｐｙ１）ｔｒｉｅｔｈｏｘｙｓｉｌａｎｅ ｆｕｎｃｔｉｏｎａｌｉｚｅｄ ｓｉｌｉｃａ ｎａｎｏｐａｒｔｉｃｌｅｓ （Ｓｉ０２－ＭＰＴＥＳ）ｐｌａｙ ａｎ ｉｍｐｏｒｔａｎｔ ｒｏｌｅ ｉｎ ｔｈｅ ｓｅｌｅｃｔｉｖｅ ａｄｓｏｒｐｔｉｏｎ ｏｆ Ｃｕ ａｎｄ Ｈｇ ，ｔｈｅ（３－Ａｍｉｎｃｐｒｏｐｙ１）ｔｒｉｔｈｏｘｙｓｉｌａｎｅ（ＡＰＴＥＳ） ｆｕｎｃｔｉｏｎａｌｉｚｅｄ ｓｉｌｉｃａ ｎａｎｏｐａｒｔｉｃｌｅｓ（ＳｉＯ２－ＡＰＴＥＳ）ｅｘｈｉｂｉｔｅｄ ｍａｘｉｍｕｍ ｒｅｍｏｖａｌ ｅｆｆｉｃｉｅｎｃｙ ｔｏｗａｒｄｓ Ｐｂ ａｎｄ Ｈｇ ．ｔｈｅ １。８－Ｄｉａｍｉｎｏａｐｈａｌｅｎｅ ｆｕｎｃｔｉｏｎａｌｉｚｅｄ ｓｉｌｉｃａ ｎａｎｏｐａｒｔｉｃｌｅｓ ｗａｓ ｅｘｃｅｌｌｅｎｔ ｆｏｒ ｒｅｍｏｖａｌ ｏｆ Ｈｇ ａｔ ｒｏｏｍ ｔｅｍｐｅｒａｔｕｒｅ．ｒｅｓｐｅｃｔｉｖｅｌｙ．
Ｋｅｙ ｗｏｒｄｓ：ｉｎｄｕｓｔｒｉａｌ ｓｉｌｉｃａ ｆｕｍｅ；ｓｕｒｆａｃｅ自ｌｎｃｔｉｏｎａＩｉｚａｔｉｏｎ：ｈｅａｖｙ ｍｅｔａｌ ｉｏｎｓ；ｓｅｌｅｃｔｉｖｅ ｒｅｍｏｖａｌ
１ ＩｎｔｒＯｄｕｃｔｉ０ｎ Ｉｎｄｕｓｔｒｉａｌ ａｎｄ ｃｈｅｍｉｃａｌ ｐｒｏｃｅｓｓｅｓ ｈａｖｅ ｗｏｒｓｅｎｅｄ ｔｈｅ ｃｏｎｔａｍｉｎａｔｉｏｎ ｏｆ ｓｕｒｆａｃｅ ｗａｔｅｒ ａｎｄ ｇｒｏｕｎｄｗａｔｅｒ ｒｅｓｕｌｔｉｎｇ ｆｒｏｍ ｈｅａｖｙ ｍｅｔａｌ ｉｏｎｓ．ａｎｄ ｈａｖｅ ｉｎｃｒｅａｓｅｄ ｃｏｎｃｅｒｎ ｆｏｒ ｔｈｅ ｈｉｇｈ ｔｏ・ｘｉｃ ｅｆｒｅｃｔ ｏｆ ｓｕｃｈ ｃｏｎｔａｍｉｎａｔｉｏｎ ｔｏ ｔｈｅ ｅｎｖｉｒｏｎｍｅｎｔ ａｎｄ ｐｕｂｌｉｃ ｈｅａｌｔｈ．Ｔｈｅ ａｃｃｕｍｕｌａｔｉｖｅ ｏｆ ｈｅａｖｙ ｍｅｔａｌｉｎ ｔｈｅ ｂｏｄｙ ｃａｎ ｌｃａｄ ｔｏ ｍａｎｙ ｓｅｒｉｏｕｓ ｈｕｍａｎ ａｍｉｃｔｉｏｎｓ．Ｕｎｌｉｋｅ ｓｏｍｅ ｏｒｇａｎｉｃ ｐｏｌｌｕｔａｎｔｓ．ｈｅａｖｙ ｍｅｔａｌｓ ａｒｅ ｎｏｔ ｂｉｏｄｅｇｒａｄａｂｌｅ ａｎｄ ｃａｎｎｏｔ ｂｅ ｄｅｃｏｍｐｏｓｅｄ． Ｔｈｅｒｅｆｏｒｅ．ｅ虢ｃｔｉｖｅ ｍｅｔｈｏｄｓ ａｒｅ ｎｅｅｄｅｄ ｔｏ ｒｅｍｏｖｅ ａｎｄ ｄｅｔｅｃｔ ｈｅａｖｙ ｍｅｔａｌｓ ｉｎ ｅｎｖｉｒｏｎｍｅｎｔａｌ ａｎｄ ｂｉｏｌｏｇｉｃａｌ ｓａｍｐｌｅｓ． Ｉｎ ｒｅｃｅｎｔ ｄｅｃａｄｅｓ，ａ ｌａｒｇｅ ｎｕｍｂｅｒ ｏｆ ｒｅｓｅａｒｃｈｅｓ ｈａｖｅ ｂｅｅｎ ｆｏｃｕｓｅｄ ｏｎ ｔｈｅ ｅｆｆｅｃｔｉｖｅ ｒｅｍｏｖａｌ ｏｆ ｈｅａｖｙ ｍｅｔａｌ ｉｏｎｓ．Ｔｈｅ ｔｒａｄｉｔｉｏｎａｌ ｍｅｔｈｏｄｓ ｃｏｍｍｏｎｌｙ ｕｓｅｄ ｆｏｒ ｒｅｍｏｖａｌ ｆｒｏｍ ａｑｕｅｏｕｓ ｓｏｌｕｔｉｏｎｓ ｉｎｃｌｕｄｅ ｉｏｎ．ｅｘｃｈａｎｇｅ ［１］，ｓｏｌｖｅｎｔ ｅｘｔｒａｃｔｉｏｎ［２—３］，ｃｈｅｍｉｃａｌ ｐｒｅｃｉｐｉｔａｔｉｏｎ［４］， ｍｅｍｂｒａｎｅ ｓｅｐａｒａｔｉｏｎ［５—６】，ｍｏｌｅｃｕｌａｒ ｉｍｐｒｉｎｔｉｎｇ［７】， ａｄｓｏｒｐｔｉｏｎ［８—１２］．Ｔｈｅ ａｄｓｏｒｐｔｉｏｎ ｐｒｏｃｅｓｓ ｉｓ ａｒｇｕａｂｌｙ ｏｎｅ ｏｆ ｔｈｅ ｍｏｓｔ ｐｏｐｕｌａｒ ｍｅｔｈｏｄｓ ｆｏｒ ｒｅｍｏｖａｌ ａｎｄ ｈａｓ ａｔｔｒａｃｔｅｄ ｇｒｅａｔｅｒ ｉｎｔｅｒｅｓｔｓ ｂｅｃａｕｓｅ ｏｆ ｉｔｓ ｓｉｍｐｌｉｃｉｔｙ ａｎｄ ｅｆｆｉｃｉｅｎｃｙ．Ｒｅｃｅｎｔｌｙ，ｍａｎｙ ｒｅｓｅａｒｃｈ ｇｒｏｕｐｓ ｈａｖｅ ｅｘｐｌｏｒｅｄ ｓｅｖｅｒａｌ ｎａｎｏｐａｒｔｉｃｌｅｓ ｆｏｒ ｒｅｍｏｖａ１ ｂｅｃａｕｓｅ ｏｆ ｔｈｅ ｅａｓｅ ｏｆ ｍｏｄｉｆｙｉｎｇ ｔｈｅｉｒ ｓｕｒｆａｃｅ ｆｕｎｃｔｉｏｎａｌｉｔｙ ａｎｄ ｔｈｅｉｒ ｈｉｇｈ ｓｕｒｆａｃｅ ａｒｅａ．．ｔｏ．．ｖｏｌｕｍｅ ｒａｔｉｏ ｆｏｒ ｉｎｃｒｅａｓｅｄ ａｄｓｏｒｐｔｉｏｎ ｃａｐａｃｉｔｙ ａｎｄ ｅｆｆｉｃｉｅｎｃｙ．Ｔｈｅ ｃｈｅｌａｔｉｎｇ ｎａｎｏｍａｔｅｒｉａｌ ｉｓ ａ ｆｕｎｃｔｉｏｎａｌ ｍａｔｅｒｉａｌ ｔｈａｔ ｃａｎ ｆｏｎｉｌ ｃｏｏｒｄｉｎａｔｉｏｎ ｃｏｍｐｌｅｘｅｓ ｗｉｔｈ ｈｅａｖｙ ｍｅｔａｌ ｉｏｎｓ．ｗｈｉｃｈ ｉｓ ａ ｋｉｎｄ ｏｆ ｎｅｗ ａｄｓｏｒｐｔｉｏｎ ｍａｔｅｒｉａｌ ｄｅｖｅｌｏｐｅｄ ｉｎ ｒｅｃｅｎｔ ｙｅａｒｓ．Ｔｈｅ ｕｎｂｏｎｄｉｎｇ ｉｓｏｌａｔｅｄ ｅｌｅｃｔｒｏｎｓ ｅｘｉｓｔｉｎｇ ｉｎ ｃｈｅｌａｔｉｎｇ ｇｒｏｕｐｓ ｃａｎ ｆｏｒｍ ａ ｓｔａｂｌｅ ｃｈｅｌａｔｅ ｗｉｔｈ ｈｅａｖｙ ｍｅｔａｌ ｉｏｎｓ．Ｔｈｅｒｅｆｏｒｅ， ａｄｓｏｒｐｔｉｏｎ ｏｆ ｃｈｅｌａｔｉｎｇ ｎａｎｏｍａｔｅｒｉａｌｓ ｉｓ ｍｏｒｅ ｓｐｅｃｉｆｉｃ ｔｈａｎ ｔｒａｄｉｔｉｏｎａｌ ｎａｎｏｍａｔｅｒｉａｌｓ ｂｅｃａｕｓｅ ｏｆ ｔｈｅｉｒ ｈｉｇｈｅｒ ｓｅｌｅｃｔｉｖｉｔｙ ｃｏｍｂｉｎａｔｉｏｎ ｗｉｔｈ ｍｅｔａ１ ｉｏｎｓ．Ｐｒｅｖｉｏｕｓ １ｉｔｅｒａｔｕｒｅ ｒｅｐｏｒｔｅｄ ｔｈｅ ｕｓｅ ｏｆ ｃｈｅｌａｔｉｎｇ ｌｉｇａｎｄｓ ｆｕｎｃｔｉｏｎａｌｉｚｅｄ ｏｎｔｏ ｓｉｌｉｃａ ｆｏｒ ｈｅａｖｙ ｍｅｔａｌ ｅｘ仃ａｃｔｉｏｎ ａｎｄ ｒｅｍｏｖａ１．Ｆｏｒ ｅｘａｍｐｌｅ．５ ｆｏｒｍｙｌ一３－（１’一ｃａｒｂｏｘｙｐｈｅｎｙｌａｚｏ）ｓａｌｉｃｙｌｉｃ ａｃｉｄ ｗａｓ ｕｓｅｄ
Ｆｏｕｎｄａｔｉｏｎ ｉｔｅｍ：Ｐｒ０ｊｅｃｔ（２０ｌ２ｃＢ７２２８Ｏ３）ｓｕｐｐｏｓｅｄ ｂｙ ｔｈｅ Ｋｅｙ Ｐｒｏｊｅｃｔ ｏｆＮａｔｉｏｎａｌ Ｂａｓｉｃ Ｒｅｓｅａｒｃｈ ａｎｄ Ｄｅｖｅｌｏｐｍｅｎｔ Ｐｒｏｇｒａｍ ｏｆＣｈｉｎａ；Ｐｒｏｊｅｃｔ（Ｕ１２０２２７１） ｓｕｐｐｏｒｔｅｄ ｂｙ ｔｈｅ Ｎａｔｉｏｎａｌ Ｎａｔｕｒａｌ Ｓｃｉｅｎｃｅ Ｆｏｕｎｄａｔｉｏｎ ｏｆ Ｃｈｉｎａ；Ｐｒｏｊｅｃｔ（ＩＲＴ１２５０）ｓｕｐｐｏｓｅｄ ｂｙ ｔｈｅ Ｐｒｏｇｒａｍ ｆｏｒ Ｉｎｎｏｖａｔｉｖｅ Ｒｅｓｅａｒｃｈ Ｔｅａｍ ｉｎ Ｕｎｉｖｅｒｓｉｔｙ ｏｆＭｉｎｉｓｔｒｙ ｏｆＥｄｕｃａｔｉｏｎ ｏｆＣｈｉｎａ Ｒｅｃｅｉｖｅｄ ｄａｔｅ：２０１３——０５——１７；Ａｃｃｅｐｔｅｄ ｄａｔｅ：２０１３— １０——０６ Ｃｏｒｒｅｓｐｏｎｄｉｎｇ ａｕｔｈｏｒ：ＸＩＯＮＧ Ｈｅｎｇ，ＰｈＤ；Ｔｅｌ：＋８６—８７１—６５１６３５８３；Ｅ—ｍａｉｌ：５７１６０７４１＠ｑｑ．ｃｏｍ ’