碳纳米管溶胶对水中微量Cd~(2+)与Cu~(2+)吸附的研究

采用强酸表面氧化法对碳纳米管进行处理,制备稳定具有高效吸附性能的碳纳米管溶胶,用于去除水中低质量浓度重金属Cd2+,Cu2+。研究表明,在实验的pH值为2.5—9.5,对Cd2+的去除,吸附起主要作用,优化的pH值为6.0;对Cu2+的去除,pH<6.7时,吸附起主要作用,在pH>6.7时,金属离子沉淀是主要的去除原因,在pH=9.5时,达到最大去除率。在相同碳纳米管溶胶投加质量浓度情况下,对Cd2+的吸附去除率远远大于对Cu2+的去除。碳纳米管溶胶对Cd2+,Cu2+的吸附等温线呈线性,对Cd2+的吸附性能优于对Cu2+的吸附性能。     

废弃茶叶对水中Zn~(2+)、Cd~(2+)、Cu~(2+)的吸附研究

通过废弃茶叶对水溶液中的Zn2+、Cd2+、Cu2+的吸附实验,讨论了影响茶叶末吸附重金属的初始浓度、吸附时间、pH等影响因素。结果表明,在30 min内,废弃茶叶末对Zn2+、Cd2+、Cu2+3种金属离子的吸附达到最大,最佳pH因金属的不同而有所差异。处理单组分金属离子水溶液时,3种离子的吸附量和吸附率的大小顺序均为Cu2+Cd2+Zn2+。而处理3种金属离子的多组分溶液时,其吸附量和吸附率的顺序则为Cd2+Cu2+Zn2+。     

用于吸附重金属离子的磁性纳米伊/蒙黏土的制备

采用化学共沉淀法原位制备了一种可便于磁性回收并吸附水中重金属离子(如Pb~(2+))的磁性纳米伊/蒙黏土。通过X射线衍射、Fourier变换红外光谱、场发射扫描电子显微镜、振动样品磁强计对样品进行了表征。结果表明:合成的Fe_3O_4纳米颗粒可原位复合附着于纳米伊/蒙黏土颗粒表面,使磁性纳米伊/蒙黏土的饱和磁化强度达到26.77 A·m~2/kg,并可有效地从浆体中磁分离出来。另外,水中Pb~(2+)的吸附研究表明,磁性纳米伊/蒙黏土吸附Pb~(2+)的动力学过程符合准二级动力学模型,且pH值和磁性纳米伊/蒙黏土加入量对在浆料中吸附Pb~(2+)的效果有着显著的影响。其等温吸附过程符合Langmuir模型,其最大单层饱和吸附量为22.5 mg/g。当pH=6时,Pb~(2+)的去除率达97.79%;当磁性纳米伊/蒙黏土加入量为1 g/L时,平衡吸附量为38.7 mg/g。     

坡缕石黏土吸附Cu~(2+)的动力学

通过提纯的坡缕石黏土对水溶液中Cu~(2+)的静态吸附实验,考察了吸附过程的动力学特征,研究了吸附过程的动力学模型、表观活化能和活化热力学参数,并对吸附速率的控制进行了分析。结果表明:在实验条件下坡缕石黏土对水中的Cu~(2+)具有较快的吸附速率,60min可基本达到平衡;吸附过程能较好地符合Lagergren pseudo-second-order吸附动力学方程,速率常数k_2随温度的升高而增大,随Cu~(2+)初始浓度的增加而减小;吸附过程的表观活化能为18.82kJ/mol,是活化的化学吸附,活化焓为16.26kJ/mol,活化Gibbs自由能为75.40～79.38kJ/mol,活化熵为-198.50 J/(mol·K),活化为吸热过程,是缔合反应机制:吸附速率由液膜扩散和颗粒内扩散共同控制,低浓度时主要受液膜扩散控制,高浓度时颗粒内扩散的影响更为明显。     

三氧化二铁涂层火山岩吸附Ni~(2+)、Cd~(2+)和Cu~(2+)的研究

本试验采用水热法和高温煅烧法结合的方式制备三氧化二铁涂层火山岩。利用改性火山岩作为吸附材料对水体中三种主要重金属离子(Ni~(2+)、Cd~(2+)和Cu~(2+))的吸附机理进行了深入的研究,本试验将试验吸附温度设定为20℃,pH值对改性火山岩去除水体中的重金属离子影响十分明显,三种重金属离子的最佳p H值为5.0~6.0。     

壳聚糖/聚丙烯酸水凝胶的制备及对Cu~(2+)和Cd~(2+)的吸附

以丙烯酸(AA)和壳聚糖(CS)为原料,N,N'-亚甲基双丙烯酰胺(MBA)为交联剂,利用辉光放电电解等离子体(GDEP)技术在水溶液中一步引发制备了壳聚糖/聚丙烯酸(CS/PAA)水凝胶。采用FTIR、XRD和SEM对水凝胶的结构和形貌进行了表征,考察了溶液p H、吸附时间和初始质量浓度对Cu~(2+)和Cd~(2+)吸附的影响,探讨了水凝胶的重复利用性。结果表明:AA成功接枝到了CS链上,形成了具有多孔三维网络结构的CS/PAA水凝胶;该水凝胶对Cu~(2+)和Cd~(2+)的吸附符合准二级动力学模型和Langmuir吸附等温式;在最佳吸附p H下(p H=4.3),吸附120 min,CS/PAA水凝胶对Cu~(2+)和Cd~(2+)的最大实际吸附量分别为151.2和298.8 mg/g;该水凝胶在0.015mol/L乙二胺四乙酸四钠(EDTA-4Na)溶液中吸附解吸4次后,吸附量变化不大,说明CS/PAA水凝胶具有优异的再生和重复利用性。     

小球藻吸附水体中Cd~(2+)、Pb~(2+)和Cu~(2+)的试验研究

为了研究小球藻藻体吸附水体中Cd2+、Pb2+和Cu2+的情况,在检测了典型电子垃圾处理区水体中重金属Cd、Pb和Cu浓度的基础上,采用冷冻干燥的小球藻藻体在模拟重金属离子溶液中进行吸附试验。结果表明,水体中重金属Cu的浓度较高,Cd和Pb的污染程度较严重。藻体对于Pb2+的去除效果较好,去除率和去除量分别达到88.42%和13.262 4 mg/g;Cu2+的去除率较低,但去除量高达17.480 6 mg/g;Cd2+去除率较高,但去除量仅有0.433 7 mg/g。     

羟基磷灰石/膨润土复合材料对水中Cd~(2+)吸附研究

采用共沉淀法制备羟基磷灰石/膨润土(HA/B)复合材料,用于去除水溶液中Cd~(2+)。探究了合成时温度、膨润土投加量、Ca~(2+)与PO43–浓度、高温灼烧对吸附的影响。研究了吸附动力学及热力学,分析了Cd~(2+)的吸附机理,研究了pH、阴离子对Cd~(2+)吸附性能的影响以及与阳离子的竞争作用。结果表明,羟基磷灰石成功地负载在膨润土表面;最佳制备条件为:制备温度30℃,羟基磷灰石与膨润土的最佳配比为1:1,Ca(NO3)2的浓度为8.23 g/L,高温灼烧不利于材料的吸附;伪二级动力学模型和Langmuir等温模型能很好地描述Cd~(2+)在HA/B上的吸附,表明吸附以化学吸附为主;热力学表明该吸附是自发的、吸热的过程;F–促进吸附,Cl–抑制吸附,Cu~(2+)、Ca~(2+)、Pb~(2+)、NH4+对Cd~(2+)吸附的干扰大小顺序为:Cu~(2+)Pb~(2+)Ca~(2+)NH4+。     

啤酒酵母吸附去除水中Cd~(2+)的影响因素

生物吸附法是一种经济有效的处理大规模低浓度重金属废水的生物技术,其中啤酒酵母(Saccharomyces cerevisiae)是具有实用潜力的生物吸附剂。本文研究了啤酒酵母对Cd2+吸附效果的主要影响因素,结果表明pH值对Cd2+会产生较大的影响,非固定化和固定化啤酒酵母对Cd2+吸附的最佳pH值都为4,过高和过低均不利于吸附的进行。水中常见的K+、Ca2+、Na+、Mg2+四种离子在低浓度时对Cd2+的吸附无显著影响,但当其浓度高于5mg/L时会影响吸附,其影响顺序为K+Na+Ca2+Mg2+;Zn2+、Fe2+、Cu2+、Pb2+对Cd2+的吸附效果影响顺序为Pb2+Zn2+Fe2+Cu2+;当Cu2+浓度≥50mg/L时,啤酒酵母对Cd2+不产生性吸附,而对Cu2+产生专性吸附。     

环氧氯丙烷改性花生壳吸附水中Cu~(2+)的研究

利用环氧氯丙烷对花生壳改性制备吸附剂,并用其吸附水溶液中Cu2+。实验结果显示,花生壳的改性条件为:花生壳5.0 g,浓度为1.5 mol/L NaOH溶液100 mL,环氧氯丙烷5 mL,反应温度30℃,反应40 min;用上述条件改性花生壳0.3 g,吸附初始浓度50 mg/LCu2+溶液,控制溶液的pH为5.0,吸附时间3.0h,对Cu2+吸附率可达96.0%,高于未改性花生壳的70.4%,使吸附率提高36.4%。     

Removal of Copper in Aqueous Solution by Apple Wastes

Abstract

Removal of copper from a solution was investigated to evaluate the cation-exchange capacities of apple residues from agricultural wastes. The effects of solution pH, ionic strength, co-ion, ligands, initial metal concentrations, and particle size of apple residues were studied. The optimal pH range for copper removal by apple residues was shown to be from pH 5.5 to 7.0, and the maximum percentage of copper removal was 91.2%. Increasing ionic strength, up to 0.1 N, has little effect on metal uptake. The presence of co-ions such as lead decreases the removal capacity of copper as expected. The presence of ligands, such as EDTA and ammonia, also reduces metal removal efficiency due to the formation of a metal-ligand complexation in solution. Equilibrium of copper sorption was established very rapidly initially and decreased markedly after 1 hour. Equilibrium isotherms of copper fit the Langmuir equation adequately. Column experiments showed that the dynamic capacity of chemically modified apple residues was four to five times higher than that of raw residues which contained acidic groups such as carboxylic and phenolic functional groups. The adsorbed copper ions were completely recovered with three bed volumes of 0.5 N HCl. Thus, modified apple residues could be applied successfully for metal removal from wastewater.     

交联壳聚糖磁性颗粒吸附去除水溶液中的铜

The performance of cross-linked magnetic chitosan, coated with magnetic fluids and cross-linked with epichlorohydrin, was investigated for the adsorption of copper (II) from aqueous solutions. Infrared spectra of chitosan before and after modification showed that the coating and cross-linking are effective. Experiments were performed at different pH of solution and contact time, and appropriate conditions for the adsorption of Cu(II) were determined. Experimental equilibrium data were correlated with Langmuir and Freundlich isotherms for determination of the adsorption potential. The results showed that the Langmuir isotherm was better compared with the Freundlich isotherm, and the uptake of Cu(II) was 78.13 mg&#8226;g－1. The kinetics of adsorption corresponded with the first-order Langergren rate equation, and Langergren rate constants were determined.     

Removal of Cadmium Ions from Aqueous Samples by Synechocystis sp.

Abstract

The biosorption of cadmium ions from aqueous solution by dried, immobilized dried and immobilized live Synechocystis sp. was investigated. Sorption of plain Ca-alginate beads, which were used as substrate for immobilization, was also studied for comparison. Removal efficiency of biosorbents was studied as a function of pH (2-8 Volesky , B. ( 1990 ) Biosorption of Heavy Metals ; CRC Press : Boca Raton , FL . Wase , J. , Forster , C.F. (1997) Biosorbents for Metal Ions ; Taylor & Francis : London. Malkoç , E. ; Nuho?lu , Y. ( 2005 ) Investigations of nickel (II) removal from aqueous solutions using tea factory waste . J. Hazard. Mater. , 127 : 120 – 128 . Lodeiro , P. ; Cordero , B. ; Barriada , J.L. ; Herrero , R. ; Sastre de Vicente , M.E. ( 2005 ) Biosorption of cadmium by biomass of brown marine macroalgae . Bioresource Technol. , 96 : 1796 – 1803 . Shen , J. ; Duvnjak , Z. ( 2005 ) Adsorption isotherms for cupric and cadmium ions on corncob particles . Sep. Sci. Technol. , 40 : 1461 – 1481 . Kat?rc?o?lu , H. ; Asl?m , B. ; Türker , A.R. ; At?c? , T. ; Beyatl? , Y. ( 2008 ) Removal of cadmium(II) ion from aqueous system by dry biomass, immobilized live and heat-dried Oscillatoria sp. H1 isolated from freshwater (Mogan Lake) . Bioresource Technol. , 99 ( 10 ): 4185 – 4191 . Pavasant , P. ; Apiratikul , R. ; Sungkhum , V. ; Suthiparinyanont , P. ; Wattanachira , S. ; Marhaba , T.F. ( 2006 ) Biosorption of Cu²⁺, Cd²⁺, Pb²⁺, and Zn²⁺ using dried marine green macroalga Caulerpa lentillifera. Bioresource Technol. , 97 : 2321 – 2329 . ), temperature (20–40°C), initial cadmium ion concentration (50–300 mg/L), and contact time (0–120 min). The maximum biosorption capacities of the dried, immobilized dried, and immobilized live Synechocystis sp. and plain Ca-alginate beads were found as 75.7, 4.9, 4.3, and 3.9 mg/g, respectively at optimum conditions. Biosorption equilibrium was established in about 15 min. Dried biomass of Synechocystis sp. was found to be more suitable and an efficient biosorbent for the removal of cadmium ion from aqueous solution. Both of the isotherm models (Langmuir and Freundlich) were suitable for describing the biosorption of cadmium by the dried biomass of Synechocystis sp. All the tested cyanobacterial forms could be recovered more than 90% and reused in five biosorption–desorption cycles without any considerable loss in the biosorption capacity.     

泡沫分离除去水溶液中微量金属离子

以十二烷基苯磺酸为表面活性物质,采用泡沫分离技术分别对脱除水溶液中微量的铁、铜、钠离子的分离过程进行了研究.重点考察了溶液的pH、表观气速、表面活性剂浓度及泡沫塔装液量对分离效果的影响.结果表明在各自最佳操作条件下铁离子(Ⅲ)的去除率为95.2%,富集比为13.6;铜离子(Ⅱ)的去除率为94.6%,富集比为16.5;钠离子去除率为73.1%,富集比为32.3.与常规的表面活性剂十二烷基硫酸钠相比,十二烷基苯磺酸在泡沫分离过程结束后不会在体系中引入新的金属离子,这为探索脱盐新方法提供了依据.     

壳聚糖对含镍废水的吸附研究

研究了壳聚糖通过反渗透膜技术对水溶液中镍的吸附作用,运用正交分析法考察了振荡温度,振荡时间,废液投加量和吸附剂投加量对镍去除率的影响。筛选出壳聚糖在反渗透膜技术中的最佳工艺条件:振荡时间50min,振荡温度50℃,废液投加量5m L,吸附剂投加量25m L,净化率达到了73.5%。     

Removal of Co2+ Ions from Aqueous Solution by Ferrite Process

Abstract

A mathematical model was developed to investigate the characteristics of Co²⁺ removal by the pre-formed ferrite process. In this study, surface adsorption, hydrolysis-precipitation, and ion exchange were considered as Co²⁺ removal mechanisms, and incorporated into the model. In addition, a series of batch experiments was performed to remove Co²⁺ ions from aqueous solution, and the removal characteristics of Co²⁺ were analyzed by considering equilibrium pH, shaking time, ionic strength, and the effect of EDTA and Ca²⁺ as a chelating agent and a competing cation, respectively. Finally, the model proposed in this study was applied to the given experimental system, and it turned out that the pH-edge could be successfully predicted by the model. The experimental results were well-fitted by a Freundlich isotherm, and the standard enthalpy change of the reaction was 25.02 kJ·mol^?1. The removal efficiency was slightly diminished by increasing the ionic strength and the initial concentration of Co²⁺; however, the effect of the competing cation, Ca²⁺, was negligible.     

蒙脱石和高岭石吸附水溶液中重金属离子的实验研究

综述了近几年研究人员以蒙脱石、高岭石和膨润土作为吸附材料,去除水溶液中的砷、镉、铬、铜、铅几种重金属离子。通过酸性活化改性,有机分子嫁接改性,纳米氧化物涂层和柱撑等手段,提高了粘土矿物的吸附性能,达到更好的吸附效果。结果表明有机改性更有利于蒙脱石等粘土矿物对于重金属离子的吸附,同时指出pH是影响吸附效果的关键因素。     

竹炭对水体中重金属离子的吸附规律研究

在竹炭对重金属汞(Ⅱ)、铅(Ⅱ)、锌(Ⅱ)、镉(Ⅱ)、铬(Ⅵ)吸附性能研究的基础上,探讨了竹炭对水体中重金属离子的吸附规律.研究了离子形态、重金属离子的初始浓度、竹炭量、温度对吸附的影响,以及竹炭的粒径及性质对吸附的影响.为竹炭在重金属废水处理中的应用提供了科学依据.     

羟基磷灰石对水溶液中锌离子的吸附动力学研究

以废弃的鸡蛋壳为原料,制备了碳羟基磷灰石,用红外光谱对其结构进行了表征。将得到的碳羟基磷灰石进行水溶液中锌离子的吸附,考察了吸附过程的动力学,结果表明,碳羟基磷灰石对水溶液中锌离子的吸附符合二级反应动力学方程：1/ρR=0.0536t＋1.0992,相关系数R=0.99724,其拟合度比较好。     

Removal of Cesium Ions from Aqueous Solution by Polyaniline: A Radiotracer Study

The present work deals with the study of uptake behavior of cesium ions by polyaniline applying a radiotracer technique. The parametric study reveals that the increase of adsorbate concentration (10⁻⁸ to 10⁻³ mol dm⁻³) and temperature (303 to 333 K) enhances the removal of the ions and from thermal and kinetic data it is inferred that the adsorption of cesium ions follows first order rate law, obeys Freundlich isotherm and is endothermic in nature. The radiation stability of polyaniline was also investigated by exposing it to a 11.1 GBq (Ra-Be) source associated with gamma dose of 1.72 Gyh⁻¹.