新型功能化改性生物质吸附剂的制备及其对重金属铜的吸附性能研究

为有效解决自然水体中重金属污染的问题,以来源广泛、成本低廉、可再生的废弃生物质材料(花生壳、玉米芯、白果壳、树皮等)为基体,通过表面预处理、高温炭化以及后功能化改性(包括硫酸、硝酸、柠檬酸、高锰酸钾活化)等工艺制备了一系列高效多孔生物吸附剂材料。结果表明,经过高锰酸钾氧化改性的生物吸附剂(花生壳、玉米芯、白果壳、树皮)对重金属铜的吸附率最高,分别达到79.4%、65.3%、83.9%、71.8%,与原始生物材料吸附效果相比,吸附容量显著提高了66.2%、53.7%、70.7%、53.1%。同时,优化了高锰酸钾改性吸附剂对铜的吸附条件(时间、温度、pH)。经过结构特性表征分析,改性后的吸附剂相较于改性之前生物材料比表面积更大、孔隙结构更多,较大幅度提升了对于重金属离子的吸附能力。该研究所开发的高效生物质吸附剂为环境中重金属离子的消除以及资源化利用提供了一种廉价高效的新方法、新思路,同时也提供了一种绿色高效处理农林业废弃物的途径。     

农业废弃物去除水体中磷的研究综述

磷是引起水体富营养化、藻类爆发的主要控制因素,从水中去除磷是控制水体富营养化的一项重要举措。本文综述了用农业废弃物作为吸附剂去除水体中磷的研究进展。研究发现为提高磷的去除效率,需要对农业废弃物进行改性。吸附剂不同和改性方法不同,吸附机理和影响吸附效率的因素也不同。采用农业废弃物去除水中的磷具有成本低、吸附材料易得、去除效率高、能对磷进行回收、不会对环境产生影响等优点。     

改性膨润土处理重金属离子废水的研究进展

重金属离子对人体有害,在废水中很难处理,利用廉价吸附剂有效处理重金属离子,既经济又环保。膨润土价廉易得,比表面积大,吸附性好,是一种天然的矿物质吸附剂。文章总结了膨润土吸附重金属离子的机理,并分析了改性膨润土在吸附重金属离子方面的研究进展及存在问题,并提出了解决办法。     

锯末吸附污染物的研究进展

锯末是价格低廉且来源广泛的工农业废弃物,其作为吸附剂在污染治理中越来越受到青睐。本文首先介绍了锯末吸附作用的原理和影响吸附效果的因素,然后概述了锯末在染料、重金属、油类等水体污染物和气体污染物处理中的应用研究状况,最后对未来锯末吸附污染物的应用研究进行了展望。     

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。     

污水处理中氨氮吸附剂的类型及经济性比较分析

介绍了目前国内外对污水中氨氮吸附效果较好的几种吸附剂,论述了这些吸附剂的基本结构、对氨氮的吸附机理、性能特点、改性方法、研究现状、在我国的分布情况以及氨氮吸附剂联用的应用现状。以阜新地区丰富的沸石、粉煤灰和膨润土资源为例,在同等条件下,分析、计算比较了各自吸附氨氮的水处理成本,结果表明沸石比较经济。在实际应用中,要因地制宜选择一种高性价比的氨氮吸附剂。     

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。     

吸附法去除地下水铁锰的研究进展

为了解决地下水铁、锰含量过高的问题,在众多研究方法中,吸附法由于具有容量大、耗能少、污染小、去除快和可循环等优点,被广泛应用于地下水除铁除锰中。重点介绍了锰砂、沸石、火山岩、生物质、活性炭和硅碳素等吸附剂的吸附原理与吸附效果,阐述了一部分吸附剂的改性效果与影响因素。指出了各种吸附剂未来的改进方法和研究方向锰砂可以通过改性来弱化pH值等影响因素对它的吸附影响,沸石和火山岩的研究重心可继续放在改性上,重点研究污染区域的生物质的吸附效果,研究硅碳素与其他吸附剂联合吸附的效果。     

改性花生壳和木屑对水中活性艳红的吸附研究

用经过磷酸改性的花生壳和木屑制成混合吸附剂对水中活性艳红K-2BP进行吸附研究,通过静态试验系统地考察了混合吸附剂中改性花生壳和木屑的质量比、混合吸附剂的投加量、p H、温度和振荡速率等重要因素对K-2BP吸附效果的影响,并对吸附机理进行了探讨。研究结果表明:改性花生壳和木屑对10 mg/L K-2BP吸附的最佳条件为:改性花生壳和木屑的质量比1∶3.5,混合吸附剂的投加量0.9 g,温度328 K,p H值14,振荡速率120r/min,水中K-2BP的去除率可达98.6%,影响因素中p H值的影响最大。Langmuir吸附模型和伪二级动力学模型能较好地描述混合吸附剂对水中K-2BP的吸附过程,理论的最大吸附量为10.83 mg/g,吸附过程为吸热反应,可自发进行,因此改性花生壳和木屑吸附K-2BP技术在实际污染处理中具有良好的应用前景。     

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。     

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.     

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。     

利用吸附法处理废水中磷酸盐的研究进展

水体富营养化是世界各国面临的重大环境污染问题之一,磷是水体富营养化最关键的因素之一。因此,高效除磷可以有效控制水体富营养化。简述了吸附法除磷的优势,列举黏土矿物类吸附材料、金属氧化物类及金属矿物类吸附材料、生物质类吸附材料、活性炭等对磷酸盐的吸附效果与机理,并详细分析黏土矿物类吸附材料中的蒙脱石、蛭石、白云石、凹凸棒石等与金属氧化物类及金属矿物类吸附材料中的金属氧化物、水滑石、铁矿石、矿渣的实际吸附效果。最后,指出吸附剂吸附除磷的一些缺陷和有待改进的地方,归纳总结出改性吸附剂将继续是未来的研究热点。     

Enhancement of removal efficiency of heavy metal ions by polyaniline deposition on electrospun polyacrylonitrile membranes

This paper describes the preparation of a membrane of polyacrylonitrile(PAN) and its corresponding membrane coated with polyaniline(PANI) for the adsorption of heavy metal ions.Scanning electron microscopy micrographs revealed that all the membranes exhibited nanofibrous morphology.The prepared membranes were characterized by Fourier transform infrared spectroscopy(FTIR).The prepared membranes were used as an adsorbent for hazardous heavy metal ions Pb~(2+) and Cr_2 O_7~(2-).The adsorption capacity and the removal efficiency of the membranes were examined as function of the initial adsorbate concentration and pH of the medium.Coated membranes with PANI showed better adsorption performance and their direct current(DC) conductivities were correlated to heavy metal ion concentrations.Adsorption isotherms were also performed,and the adsorption process was tested according to the Langmuir and Freundlich models.The regeneration and reuse of the prepared membranes to re-adsorb heavy metal ions were also investigated.The enhancement in adsorption performance and reusability of PANI-coated membranes in comparison with non-coated ones is fully discussed.The results show that the maximum adsorption capacities of lead and chromate ions on the PANI-coated membranes are 290.12 and 1 202.53 mg/g,respectively.     

Comparison of surface functional groups and metal uptake efficiency of rice husk harvested from different climatic zones

Rice husk (RH) is a very effective natural adsorbent for fast removal of heavy metal cations from water solutions. Application of RH for removal of some heavy metal ions, such as Ni, Zn, Mn, Co, Cu, Pb and Cd from water solutions has been studied and different maximum adsorption capacities and a variety of optimized conditions were reported in the literature. In this work, the efficiency of RH harvested from different climatic regions was studied. For this proposal, different RH samples were collected from three different climatic regions of Iran (nominated as RH1 to RH3); their removal efficiencies of heavy metal cations of Ni(2+), Cu(2+) and Cd(2+) were investigated and compared. The adsorption data at optimum conditions could be assessed well by both Langmuir and Freundlich models. Statistical analysis of the results of adsorption isotherms showed that different RH samples have different efficiencies in uptake of these heavy metal ions. The RH samples were characterized using Fourier transform infrared spectroscopy and Boehm titration, which indicated that amounts of functional groups differed between RHs that are grown in different climatic conditions.     

Pollutant removal efficiency of alternative filtration media in stormwater treatment.

Sorption experiments were used to assess the ability of various materials (sand, compost, packing wood, ash, zeolite, recycled glass and Enviro-media) to remove heavy metal contaminants typically found in stormwater. Compost was found to have the best physicochemical properties for sorption of metal ions (Cu, Zn and Pb) compared with sand, packing wood, ash, zeolite and Enviro-media. The compost sorption of these metal ions conformed to the linear form of the Langmuir adsorption equation with the Langmuir constants (q,) for Zn(ll) being 11.2 mg/g at pH 5. However, compost was also found to leach a high concentration of dissolved organic carbon (DOC, 4.31 mg/g), compared with the other tested materials. Various combinations of sand, compost and other materials were observed to have excellent heavy metal removal (75-96% of Zn and 90-93% of Cu), with minimal DOC leaching (0.0013-2.43 mg/g). The sorption efficiency of the different Enviro-media mixes showed that a combination of traditional (sand) and alternative materials can be used as an effective medium for the treatment of dissolved metal contaminants commonly found in stormwater. The application of using recycled organic materials and other waste materials (such as recycled glass) also provides added value to the products life cycle.     

Poly(acrylic acid) modifying bentonite with in-situ polymerization for removing lead ions

In this paper, a new kind of poly(acrylic acid) modified clay adsorbent, the poly(acrylic acid)/bentonite composite (PAA/HB) was prepared by in-situ polymerization, and utilized to remove lead(II) ions from solutions. The maximum adsorption of adsorbent is at pH 5 for metal ions, whereas the adsorption starts at pH 2. The effects of contact time (5-60 min), initial concentration of metal ions (200-1,000 mg/L) and adsorbent dosage (0.04-0.12 g/100 mL) have been reported in this article. The experimental data were investigated by means of kinetic and equilibrium adsorption isotherms. The kinetic data were analyzed by the pseudo-first-order and pseudo-second-order equation. The experimental data fitted the pseudo-second-order kinetic model very well. Langmuir and Freundlich isotherms were tried for the system to better understand the adsorption isotherm process. The maximal adsorption capacity of the lead(II) ions on the PAA/HB, as calculated from the Langmuir model, was 769.2 mg/g. The results in this study indicated that PAA/HB was an attractive candidate for removing lead(II) (99%).