壳聚糖插层高岭土吸附处理电镀废水中的重金属离子

利用壳聚糖插层天然高岭土制备复合吸附剂去除电镀废水中重金属离子的相关研究不多。将天然高岭土活化处理后置于经乙酸溶解的壳聚糖溶胶中,制得壳聚糖插层高岭土复合吸附剂;优化了复合吸附剂的制备条件,考察了pH值、吸附时间以及复合吸附剂的投加量对电镀废水中Cr~(6+)、Ni~(2+)、Cd~(2+)、Pb~(2+)4种重金属离子吸附效果的影响;确定了复合吸附剂的最优制备条件:高岭土预处理温度为700℃,壳聚糖与高岭土的质量比为1∶5。电镀废水中重金属离子最佳脱除条件:pH值为5.0~6.0,吸附时间为60min,投加量为6.0g/L。常温下Cr、Ni、Cd、Pb4种重金属的去除率分别为94.76%、98.58%、92.47%、99.30%。连续5次吸附-解吸循环结果表明,插层复合吸附剂的去除率均大于90%,适用于去除电镀废水中的重金属离子。     

复合吸附剂麦饭石-壳聚糖的制备及对Zn~(2+)的吸附性能

含重金属离子的废水对人体和环境有极大的影响,采用吸附法对其进行处理,效果较好,但成本高,不易推广.为此,利用麦饭石负载壳聚糖制备了一种价廉的复合吸附剂.通过X射线衍射(XRD)和扫描电子显微镜(SEM)对其结构进行了表征,研究了不同pH值、不同吸附时间、不同吸附剂投加量对复合壳聚糖吸附Zn2+的影响.结果在pH值为6～8、吸附时间为40 min、复合吸附剂的投加量为4.0 g/L的条件下,复合吸附剂对Zn2+的吸附率达到95%以上,达到国家污水综合排放标准.通过对试验数据运用相关数学模型拟合,复合吸附剂对Zn2+的吸附符合Langmuir吸附等温式,其相关系数R2为0.965 1.因而复合吸附剂麦饭石-壳聚糖可有效地处理含锌废水.     

壳聚糖在水处理中的应用进展

壳聚糖及其衍生物具有其它人工合成絮凝剂无法比拟的安全无毒、对环境友好等诸多优点,可以去除水中颗粒状和溶解性污染物,在水处理中有着广泛的应用。天然高分子聚合物壳聚糖可以处理含重金属离子的工业废水,还可以用于纺织、食品加工、炼油废水的絮凝处理,环境效益显著。对国内外近年来壳聚糖及其衍生物作为絮凝剂和吸附剂在水处理中的应用进行了综述,并探讨了壳聚糖作为绿色水处理剂的未来发展方向。     

改性壳聚糖对废水中镍离子的吸附研究

通过原位共沉淀法研究了改性壳聚糖对废水中镍离子的吸附性能。考察了吸附剂用量、时间、温度对镍离子吸附率的影响,实验结果表明:壳聚糖对废水中镍离子的吸附在60min达到平衡,其动力学行为更好的符合准二级动力学模型,吸附过程是一个放热过程,随着温度的升高,镍离子的吸附率增大。     

累托石-壳聚糖复合材料的制备及对Ni~(2+)的吸附

将累托石与壳聚糖混合制得一种复合吸附剂.研究了累托石-壳聚糖吸附剂制备的条件和利用该复合吸附剂对含镍水溶液进行吸附.研究结果表明:当壳聚糖与累托石的比为0.06,壳聚糖脱乙酰度为90%时,制成的吸附剂吸附效率高.在pH值6～8,吸附时间为30min,吸附剂用量为5.0g/L时,Ni2+的吸附率迭99%以上,处理后的水符合国家污水综合排放标准(GB8978-1996)中的一级标准.此外还对该复合吸附剂结构进行了表征.     

微波辐射下交联壳聚糖树脂的制备及吸附性能

以壳聚糖为原料,微波辐射加热条件下,利用反相悬浮法制备甲醛-戊二醛交联壳聚糖树脂,用于吸附废水中硫酸根离子。运用红外光谱、扫描电镜以及X射线能谱元素分析对吸附剂结构进行表征,采用静态吸附法考察制备条件对其吸附量的影响。结果表明:交联反应主要发生在壳聚糖的氨基(-NH2)和一级羟基(C6-OH)上;当微波辐射甲醛反应时间为15min,微波辐射戊二醛反应时间为30min,甲醛用量6mL以及戊二醛用量4mL,所得的交联壳聚糖树脂对硫酸根离子的吸附量达到最大。     

活性白土/壳聚糖复合物的制备及其吸附性能研究

用十六烷基三甲基溴化铵(CTAB)为修饰剂,对活性白土进行修饰改性。将改性后的活性白土与壳聚糖复合,通过溶液插层技术制备了活性白土/壳聚糖复合物。通过红外光谱仪(FT-IR)、热重分析仪(TGA)、X射线衍射仪(XRD)和透射电子显微镜(TEM)对所制备的活性白土/壳聚糖复合物进行表征。以对甲基橙的吸附行为作为模拟吸附实验,研究了活性白土/壳聚糖复合物的吸附性能,探讨了温度、复合吸附剂用量、甲基橙溶液浓度、吸附时间等条件对吸附剂吸附效果的影响。结果显示:修饰剂和壳聚糖显著提高了活性白土的片层间距,从而有利于提高活性白土的吸附性能。在吸附时间为30min、温度为25℃、吸附剂用量为0.06g的条件下,吸附剂具有较为优异的吸附效果。     

微波法交联壳聚糖及其活性炭复配剂处理水中卤化物

采用微波法制备了交联壳聚糖,与活性炭复配得到复合吸附剂,并研究其对水中卤化物的吸附效果。结果表明,微波法制备复合交联壳聚糖吸附剂简化了制备工艺,且吸附效果较好。     

活性白土/壳聚糖对铜离子吸附作用研究

以活性白土和壳聚糖为原料,通过简单的工艺制得了活性白土/壳聚糖。利用傅里叶红外光谱仪(FT-IR)、热重分析仪(TGA)和X射线衍射仪(XRD)对活性白土/壳聚糖的结构和热稳定性能进行了分析。结果显示,活性白土与壳聚糖形成了稳定结构的复合物,活性白土的层间距增大,说明壳聚糖填充到活性白土的层间结构中,有利于提高吸附作用。以活性白土/壳聚糖为吸附剂,铜离子(Cu2+)溶液为吸附液,研究了吸附条件对吸附剂吸附性能的影响。结果表明,在活性白土与壳聚糖质量比为1∶0.03,吸附时间为30min,吸附剂投加量为0.5g,吸附温度为50℃,溶液pH为6.0的条件下,活性白土/壳聚糖对初始浓度为10mg/L的Cu2+溶液的吸附效果较好,吸附率达到83.2%,显示了活性白土/壳聚糖良好的吸附性能。     

蒙脱石/壳聚糖/丙烯酸/丙烯酰胺四元共聚水凝胶的制备及吸附特性

采用水溶液聚合法制备了蒙脱石/壳聚糖/丙烯酸/丙烯酰胺四元共聚水凝胶，通过单因素实验分别讨论了引发剂、交联剂、中和度、单体配比、反应时间、反应温度和蒙脱石用量等因素对水凝胶吸液倍率的影响；以养殖废水中盐酸强力霉素为目标污染物，初步探索了吸附质浓度、吸附时间、吸附剂用量、温度对盐酸强力霉素吸附效果的影响。     

功能性多孔炭材料在突发性环境污染事故中的应用

多孔炭材料具有比表面积大、孔结构发达等优点，是应急处理泄漏油品、有毒化学品和废水的理想吸附剂。通过对多孔炭材料作为吸附剂在突发性环境污染事故中的应用研究进行了归纳和总结，对多孔炭材料在突发性环境污染事故中的应用前景及未来工作进行了评述和展望。讨论了突发性环境污染事故应急处置过程中基于多孔炭材料的合理技术路线和工艺条件，指出研发新型功能性多孔炭材料及做好基础数据的积累是今后研究工作的努力方向。     

Low-cost adsorbents for heavy metals uptake from contaminated water: a review

In this article, the technical feasibility of various low-cost adsorbents for heavy metal removal from contaminated water has been reviewed. Instead of using commercial activated carbon, researchers have worked on inexpensive materials, such as chitosan, zeolites, and other adsorbents, which have high adsorption capacity and are locally available. The results of their removal performance are compared to that of activated carbon and are presented in this study. It is evident from our literature survey of about 100 papers that low-cost adsorbents have demonstrated outstanding removal capabilities for certain metal ions as compared to activated carbon. Adsorbents that stand out for high adsorption capacities are chitosan (815, 273, 250 mg/g of Hg(2+), Cr(6+), and Cd(2+), respectively), zeolites (175 and 137 mg/g of Pb(2+) and Cd(2+), respectively), waste slurry (1030, 560, 540 mg/g of Pb(2+), Hg(2+), and Cr(6+), respectively), and lignin (1865 mg/g of Pb(2+)). These adsorbents are suitable for inorganic effluent treatment containing the metal ions mentioned previously. It is important to note that the adsorption capacities of the adsorbents presented in this paper vary, depending on the characteristics of the individual adsorbent, the extent of chemical modifications, and the concentration of adsorbate.     

各种吸附材料在印染废水处理中的应用

印染废水具有水量大、水质复杂、有机物含量高、可生化性差、碱性大、色度高等特点,直接排放将会造成严重的水环境污染.处理印染废水方法很多,各种方法处理效果有所不同.吸附法是印染废水脱色处理的常见技术.近年来,人们研制开发了各种各样的吸附材料,在印染废水的处理上取得了很好的效果.在介绍印染废水产生过程及水质特征的基础上,对各类吸附材料应用于印染废水的处理进行了评述,对吸附脱色技术今后的研究方向提出了建议,并指出了开发新型吸附刺(壳聚糖)的必要性.     

The Application of Carbon Nanotube/Graphene‐Based Nanomaterials in Wastewater Treatment

The treatment of organic wastewater is of great significance. Carbon nanotube (CNT)/graphene‐based nanomaterials have great potential as absorbent materials for organic wastewater treatment owing to their high specific surface area, mesoporous structure, tunable surface properties, and high chemical stability; these attributes allow them to endure harsh wastewater conditions, such as acidic, basic, and salty conditions at high concentrations or at high temperatures. Although a substantial amount of work has been reported on the performance of CNT/graphene‐based nanomaterials in organic wastewater systems, engineering challenges still exist for their practical application. Herein, the adsorption mechanism of CNT‐ and graphene‐based nanomaterials is summarized, including the adsorption mechanism of CNTs and graphene at the atomic and molecular levels, their hydrophilic and hydrophobic surface properties, and the structure–property relationship required for adsorption to occur. Second, the structural modification and recombination methods of CNT‐ and graphene‐based adsorbents for various organic wastewater systems are introduced. Third, the engineering challenges, including the molding of macroscopically stable adsorbents, adsorption isotherm models and adsorption kinetic behaviors, and reversible adsorption performance compared to that of activated carbon (AC) are discussed. Finally, cost issues are discussed in light of scalable and practical application of these materials.     

Adsorbents made from waste ashes and post-consumer PET and their potential utilization in wastewater treatment

This study was carried out to prepare low-cost adsorbents from different types of waste ashes and post-consumer PET for use in industrial wastewater treatment. PET was melted and blended with ashes. The mixture was then carbonized to form different types of adsorbents. Heavy metal leaching from the adsorbents was greatly reduced compared to leaching from the bulk ashes. The BET surface area of the adsorbents ranged from 115 to 485m(2)/g. The acidic sites on the adsorbents varied from 0.84 to 1.56meq./g, higher than that of the PET carbon. The adsorption of methylene blue (MB) or heavy metals on the adsorbents was not in accordance with their surface areas because acidic sites reaction, affinity adsorption and cation exchange all contribute to the adsorption of the adsorbents. The isotherm for MB adsorption on the adsorbents can be well described by the Langmuir or Freundlich equation but heavy metal adsorption cannot. It is believed that the adsorbents produced in this manner can be used in wastewater treatments for discoloration and heavy metal removal.     

微生物吸附剂及其在重金属废水处理中的应用

从生物吸附剂的来源、种类、生物吸附机理、影响生物吸附的主要因素、生物材料固定化技术等方面对生物吸附在重金属废水处理中的研究现状和发展进行了阐述,并提出了目前存在的问题和今后的发展方向.     

Amalgamation and application of nano chitosan cross‐linked with fish scales based activated carbon as an adsorbent for the removal of reactive dye (RB9)

The extensive discomfort in the expulsion of toxic pollutants even at mild concentrations has demanded the need for prompt methods for the evacuation of dyes and heavy metals. The effective method for depuration of dye from the effluent is by sorption. Chitosan is a bio‐polymer which is gaining an increasing interest as one of the sorbents. It was obtained from the crab shells by undergoing several chemical processes and used as an adsorbent for dye, metal removal and also for pharmaceutical purposes. Cross linking it with other co polymers will increase the capacity of adsorption to a maximum level. Fish scales are considered to be a major waste in the food industry and since it takes a long time for decomposing it is considered to be one of the pollutants. Hence it is utilised by converting it into activated carbon by preliminary treatment and into a muffle furnace. The obtained activated carbon is combined with chitosan by using a cross linker and utilised for adsorption mechanism. To analyse the effect of chitosan cross linked with activated carbon obtained from fish scales in adsorption of dye Reactive Blue 9 (RB9) to evaluate the adsorption studies, kinetics, mass transfer studies, thermodynamics of the bio adsorbent.Inspec keywords: dyes, wastewater treatment, effluents, mass transfer, activated carbon, adsorption, polymer blends, water pollution control, thermodynamics, reaction kinetics, furnaces, recycling, industrial waste, waste recovery, food processing industry, pharmaceutical industry, renewable materials, nanoparticles, toxicologyOther keywords: fish scales, activated carbon, reactive dye removal, toxic pollutants, heavy metals, bio‐polymer, nanochitosan, bio adsorbent, amalgamation, RB9 dye, industrial effluent, crab shells, adsorption method, pharmaceutical purposes, copolymers, food industry waste, waste recovery, recycling process, muffle furnace, reaction kinetics, mass transfer, thermodynamic analysis, ReactiveBlue 9, wastewater treatment, water pollution control, C     

Insights of CMNPs in water pollution control

The various toxic contaminants such as dyes, heavy metals, pesticides, rare‐earth elements, and hazardous chemicals are the major threats to all the flora and fauna. Owing to the harmful ill effects caused by the toxic contaminants, it is necessary to eliminate these compounds from the authors’ ecosystem. The chitosan magnetic nanomaterials (CMNPs) are one of the superior materials used in the wastewater treatment through various conventional technologies. The chitosan is a natural source obtained from the crustacean shells of crabs, prawns etc. The magnetic nanomaterial prepared by the reinforcement of chitosan is highly effective in the removal of heavy metals, dyes, organic matter, and harmful chemicals. It is used in various technologies such as adsorption, flocculation, immobilisation, photocatalytic technology, and bioremediation. This possesses unique surface and magnetic characteristics, Moreover, it is simple, economically feasible, and eco‐friendly material used efficiently in wastewater treatment. This review paper depicts the overview of CMNP in the industrial effluent treatment.Inspec keywords: effluents, adsorption, dyes, water pollution control, wastewater treatment, nanofabrication, nanoparticles, catalysis, industrial waste, photochemistry, flocculation, contamination, magnetic particlesOther keywords: CMNPs, water pollution control, toxic contaminants, dyes, heavy metals, pesticides, rare‐earth elements, hazardous chemicals, flora, fauna, chitosan magnetic nanomaterials, wastewater treatment, natural source, magnetic nanomaterial, organic matter, harmful chemicals, photocatalytic technology, magnetic characteristics, eco‐friendly material, industrial effluent treatment     

Preparation of adsorbents made from sewage sludges for adsorption of organic materials from wastewater

The carbon-bearing adsorbents were prepared from biochemical and surplus sludges by physical activation and chemical activation. The results indicated that the adsorbents made by way of chemical activation were better, with the optimum activator being complex of ZnCl(2) and H(2)SO(4). Moreover, the optimum preparation conditions were concentration of two activators 5 mol/L (the ratio of ZnCl(2) and H(2)SO(4) was 2:1), at the activating temperature of 550 degrees C, in the proportion of solid to liquid 1:2.5, in a period of 2h. Contrasting the active carbon, the carbon-bearing adsorbents were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectrometer (EDS), scanning electron microscope (SEM), BET and BJH. By application of those adsorbents to treatment of wastewater of urban, the treatment effect of the carbon-bearing adsorbents were better than the active carbon. On the condition that the concentration was 0.5%, the COD, P and chromaticity color removal rates of carbon-bearing adsorbent made from the biochemical sludge of sewage were higher, which were 79.1, 98.3 and 87.5%, respectively, and the dynamic adsorption capacity was 47.8 mg/g.     

Novel chitosan derivative for the removal of cadmium in the presence of cyanide from electroplating wastewater

Chitosan was chemically modified by introducing xanthate group onto its backbone using carbondisulfide under alkaline conditions. The chemically modified chitosan flakes (CMC) was used as an adsorbent for the removal of cadmium ions from electroplating waste effluent under laboratory conditions. CMC was found to be far more efficient than the conventionally used adsorbent activated carbon. The maximum uptake of cadmium by CMC in batch studies was found to be 357.14 mg/g at an optimum pH of 8.0 whereas for plain chitosan flakes it was 85.47 mg/g. Since electroplating wastewater contains cyanide in appreciable concentrations, interference of cyanide ions in cadmium adsorption was found to be very significant. This problem could be easily overcome by using higher doses of CMC, however, activated carbon was not found to be effective even at higher doses. Due to the high formation constant of cadmium with xanthate and adsorption was carried out at pH 8, cations like Pb(II), Cu(II), Ni(II) and Zn(II) did not interfere in the adsorption. Dynamics of the sorption process were studied and the values of rate constant of adsorption were calculated. Desorption of the bound cadmium from CMC was accomplished with 0.01 N H(2)SO(4). The data from regeneration efficiencies for 10 cycles evidenced the reusability of CMC in the treatment of cadmium-laden wastewater.