土壤对重金属离子的吸附

介绍了土壤对重金属离子的吸附机理,并就影响土壤对重金属离子吸附的主要因素进行了论述,对水源地保护及污水土地处理中研究重金属离子的迁移转化规律有一定的参考作用。     

提取樟油后的樟叶残渣制作重金属离子吸附剂

以提取樟油后的樟叶废弃物为原料,通过功能化处理制备生物质重金属离子吸附剂,分析了樟叶吸附剂的粒径、改性方法、用量、废水初始浓度和离子强度等因素对其Pb(II)吸附性能的影响。结果表明,樟叶吸附剂的粒径越小,吸附能力越强;经过BTCA功能化后的BTCA-CL樟叶吸附剂对Pb(II)的吸附能力最强;随着初始溶液浓度增加,樟叶吸附剂对Pb(II)吸附量逐渐提升;吸附剂用量的增加和水溶液中存在的盐离子使得其对Pb(II)吸附有所降低,其吸附机理以分子链上活性功能团与重金属离子间络合配位的化学吸附为主。樟叶吸附剂作为廉价的吸附材料,在去除废水重金属离子上具有较大的应用价值。     

硅酸盐细菌处理含重金属污水的试验与分析

结合试验分析并肯定了硅酸盐细菌在重金属污水,特别是在重金属离子含量不太高的垃圾渗滤液处理中的应用潜力,同时阐述了硅酸盐细菌去除重金属离子的三种可能的作用机理:代谢过程中分泌的草酸、柠檬酸、酒石酸和氨基酸等多种有络合官能团的有机酸,可与重金属离子形成络合物,从而减轻或消除重金属对微生物的毒害作用;可分泌大量粘稠的胞外多聚物——荚膜多糖,对重金属离子有絮凝作用;菌体细胞表面和胞外物质对某些重金属离子有吸附作用。     

农业废弃物作为吸附剂去除水中重金属研究

农业废弃物主要由纤维素和木质素组成,是一种潜在的重金属吸附剂。文中归纳了几种农业废弃物吸附剂及其改性方法,阐述了改性农业废弃物吸附重金属的机理,讨论了pH、重金属离子初始浓度、吸附剂用量、反应温度等因素对改性农业废弃物吸附能力的影响,并展望了改性农业废弃物的应用前景。     

氧化石墨烯及其复合物对水中 重金属离子吸附研究进展

氧化石墨烯作为一种新型纳米材料在水处理领域受到了人们的广泛关注,由于其具有较大的比表面积,丰富的含氧官能团,良好的亲水性,独特的物理结构,使其可吸附水中的重金属离子,且吸附能力超过诸多目前常用的吸附剂。但同时由于氧化石墨烯结构和性质的原因,限制了其在水处理领域中的发展,为了解决这个问题,可通过氧化石墨烯与其他物质结合形成氧化石墨烯复合物。介绍了氧化石墨烯的结构和性质,以及其对水中重金属离子的吸附机制及受控的影响因素;同时,也综述了氧化石墨烯复合物对水中重金属离子的吸附机制,以及其解吸与重复利用能力;此外,对氧化石墨烯及其复合物作为吸附剂去除水中重金属离子的应用潜力进行了总结和展望。     

氨基功能化CaCO3粉末材料吸附重金属离子的研究

用直接沉淀法和包覆法相结合,制得氨基功能化CaCO3粉末材料,并对其作为某些重金属离子(Pb2+、Cu2+和Mn2+)的有效吸附剂进行表征及测定。X射线衍射(XRD)、能谱分析和扫描电子显微镜(SEM)证明该材料含有CaCO3,通过红外测定可知,功能性基团(-NH2)已成功包覆于CaCO3粉末材料上。氨基对重金属离子的吸附起主要作用,考察了吸附时间、重金属离子的初始浓度和溶液的pH值对吸附的影响。     

膨润土在水处理中的应用研究与展望

论述了膨润土的类型、结构及其理化性质,介绍了利用膨润土的吸附性来处理废水中的重金属离子、有机废水、色度、氨氮的国内外研究现状。最后对其在废水处理方面进行了展望。膨润土作为一种新型吸附剂在水处理工艺中有着极为可观的应用前景。     

焙烧颗粒膨润土的制备及其对废水中Mn~(2+)的吸附研究

对膨润土颗粒吸附剂进行了制备、焙烧改性,并通过静态吸附试验,对制备的改性吸附剂处理矿山废水中的Mn2+进行了试验研究。结果表明,颗粒吸附剂制备、焙烧改性的最佳条件是:膨润土与蒸馏水质量比为25∶18、膨润土颗粒的粒径为2mm、焙烧温度为500℃、焙烧时间为1.5h。在pH 6,温度为25℃,转速50r/min,进水Mn2+105.86mg/L,吸附剂投加量0.28g/L和吸附时间60min的试验条件下,Mn2+的去除率达96%以上,且吸附剂对Mn2+的吸附符合Langmuir吸附方程。     

竹炭对水中重金属离子的吸附

简述了竹炭的结构及其性质,归纳了竹炭的改性特点及改性方法,其主要改性方法有化学浸渍法、高温热处理法、载物法及复合法;总结了几种竹炭对水中重金属离子的吸附效果及再生效果,分析了p H值、重金属离子初始浓度、吸附时间、反应温度及竹炭本身性质等因素对竹炭吸附重金属能力的影响,探讨了吸附机理,并展望了改性竹炭的应用前景。     

壳聚糖应用于水处理的化学基础

壳聚糖在污水处理中可用作絮凝剂、吸附剂和莺金属离子螯合剂.该文详细介绍了壳聚糖与污水中的几种主要污染物水溶性染料、蛋白质、微生物和重金属离子相互作用的机理,着重讨论了影响壳聚糖吸附絮凝重金属离子的主要因素.     

不同pH值条件下重金属捕集剂有效性的研究

采用高分子有机捕集剂与废水中的多种重金属离子发生螯合反应,生成稳定且不溶于水的金属螯合物来去除废水中的重金属离子。对4种捕集剂在不同pH值的条件下对含有汞、铜、镉、铅等重金属污水的去除效果进行了试验研究。结果表明,利用重金属捕集剂方法处理重金属废水的效率较高,有很好的应用前景。     

粉煤灰在我国废水处理领域的利用研究

介绍了粉煤灰处理废水的物理化学特性,指出利用粉煤灰作为废水处理中的吸附剂或混凝剂,可取得良好的处理效果,并以印染、造纸、焦化、含重金属、含氟、含磷等废水处理为例,对粉煤灰在我国废水处理领域的最新应用研究作了综述。     

Comparative evaluation of As, Se and V removal technologies for the treatment of oil refinery wastewater

In this study, a broad range of readily deployable metal removal technologies were tested on a US refinery's wastewater to determine vanadium, arsenic and selenium removal performance. The bench-scale treatability studies were designed and performed so that test conditions could be as uniform as possible given the different mechanisms of action and engineering applications of each technology. The experimental data show that both ferric precipitation and reactive filtration were able to remove As, Se and V more efficiently from the wastewater than other tested technologies. Additionally, granular ferric hydroxide (GFH) adsorption was also effective in both V and As removal. Although the thiol-SAMMS adsorbent was developed for mercury removal, it also demonstrated appreciable selenium removal. None of the tested membrane filtration technologies showed any significant metals removal. This was attributed to the dissolved form of the metals as well as the wastewater's fouling characteristics.     

Imprinted polymers for the removal of heavy metal ions from water

In wastewater treatment, the removal of heavy metals is difficult due to the limited affinity of heavy metal ions to ion exchange resins. Here imprinting polymerization is used to develop resins with high capacity and selectivity for heavy metal ions for water treatment. A random copolymer of methacrylate and methacrylamide was found to be most effective for the removal of hydrophilic metal complexes, like CdCl2, ZnCI2, and the metalloid NaH2AsO4, particularly when the porosity of these resins is increased. For hydrophobic complexes imprinting emulsion polymerization was developed and data for the effective removal of mercury dithizonate will be described. Complete removal for up to 80 ppm of cadmium and mercury with only 200 mg of imprinted resin was obtained; competition and co-imprinting experiments are described as well.     

Application of ionic liquids for the removal of heavy metals from wastewater and activated sludge

This paper presents the results of adsorption studies on the removal of heavy metals (Cr, Cu, Cd, Ni, Pb and Zn) from standard solutions, real wastewater samples and activated sewage sludge using a new technique of liquid-liquid extraction using quaternary ammonium and phosphonium ionic liquids (ILs). Batch sorption experiments were conducted using the ILs [PR4][TS], [PR4][MTBA], [A336][TS] and [A336][MTBA]. Removal of these heavy metals from standard solutions were not effective, however removal of heavy metals from the industrial effluents/wastewater treatment plants were satisfactory, indicating that the removal depends mainly on the composition of the wastewater and cannot be predicted with standard solutions. Removal of heavy metals from activated sludge proved to be more successful than conventional methods such as incineration, acid extraction, thermal treatment, etc. For the heavy metals Cu, Ni and Zn, ≥90% removal was achieved.     

Application of a bio-electrochemical reactor process to direct treatment of metal pickling wastewater containing heavy metals and high strength nitrate.

The fundamental performance of a bio-electrochemical reactor for the direct treatment of metal pickling wastewater was investigated experimentally. In the reactor, carbon anode and cathode were installed. On the cathode, denitrifying microorganisms were immobilized. Continuous experiments were carried out by feeding a synthetic wastewater containing nitrate and binary heavy metal ions, copper and lead, under different operating conditions. Acetate as well as the electric current was supplied at the minimum amount for stoichiometry of the dissimilatory denitrification reaction. The results indicated that the dissolved copper and lead removal, denitrification and neutralization could be achieved simultaneously in a single bio-electrochemical reactor. The dissolved heavy metals were removed by electrochemical deposition on cathode and by the other phenomena such as the formation of insoluble suspensions and the sorption on suspended bacterial sludge. Denitrification proceeded effectively with the utilization of both added acetate and hydrogen gas generated by electrolysis of water. The pH value increased up to around neutral due to the occurrence of denitrification in the reactor, although the influent pH was less than 3. The removal efficiencies of heavy metals and nitrate increased with increasing the current density. The applied electric current was indispensable for sustaining the stable treatment in the reactor.     

Heavy metal-binding proteins from metal-stimulated bacteria as a novel adsorbent for metal removal technology.

Water pollution with toxic heavy metals is of growing concern because heavy metals could bring about serious problems for not only ecosystems in the water environment but also human health. Some metal removal technologies have been in practical use, but much energy and troublesome treatments for chemical wastes are required to operate these conventional technologies. In this study, heavy metal-binding proteins (HMBPs) were obtained from metal-stimulated activated sludge culture with affinity chromatography using copper ion as a ligand. Two-dimensional electrophoresis revealed that a number of proteins in activated sludge culture were recovered as HMBPs for copper ion. N-termini of five HMBPs were determined, and two of them were found to be newly discovered proteins for which no amino acid sequences in protein databases were retrieved at more than 80% identities. Metal-coordinating amino acids occupied 38% of residues in one of the N-terminal sequences of the newly discovered HMBPs. Since these HMBPs were expected to be stable under conditions of water and wastewater treatments, it would be possible to utilize HMBPs as novel adsorbents for heavy metal removal if mass volume of HMBPs can be obtained with protein cloning techniques.     

Biological treatment of heavy metals in acid mine drainage using sulfate reducing bioreactors.

The uncontrolled release of acid mine drainage (AMD) from abandoned mines and tailing piles threatens water resources in many sites worldwide. AMD introduces elevated concentrations of sulfate ions and dissolved heavy metals as well as high acidity levels to groundwater and receiving surface water. Anaerobic biological processes relying on the activity of sulfate reducing bacteria are being considered for the treatment of AMD and other heavy metal containing effluents. Biogenic sulfides form insoluble complexes with heavy metals resulting in their precipitation. The objective of this study was to investigate the remediation of AMD in sulfate reducing bioreactors inoculated with anaerobic granular sludge and fed with an influent containing ethanol. Biological treatment of an acidic (pH 4.0) synthetic AMD containing high concentrations of heavy metals (100 mg Cu(2+)l(-1); 10 mg Ni(2+)l(-1), 10 mg Zn(2+)l(-1)) increased the effluent pH level to 7.0-7.2 and resulted in metal removal efficiencies exceeding 99.2%. The highest metal precipitation rates attained for Cu, Ni and Zn averaged 92.5, 14.6 and 15.8 mg metal l(-1) of reactor d(-1). The results of this work demonstrate that an ethanol-fed sulfidogenic reactor was highly effective to remove heavy metal contamination and neutralized the acidity of the synthetic wastewater.