用纤维素黄原酸酯去除硫酸锌浸出液中的重金属杂质

铜;镉;钴;镍;用纤维素黄原酸酯去除硫酸锌浸出液中的重金属杂质     

Estimation of Efficiency of Removal of Heavy Metal Ions as Hydroxides from Sewage

The minimum solubilities of heavy metal hydroxides were calculated and compared with the maximum permissible concentrations of metal ions in various water reservoirs. The efficiency of the reagent method for sewage purification, based on precipitation of heavy metal hydroxides, was estimated.     

Heavy Metal Removal from Synthetic Solutions with Magnetic Beads Under Magnetic Field

The aim of this study is to prepare magnetic beads which can be used for the removal of heavy metal ions from synthetic solutions. Magnetic poly(ethylene glycol dimethacrylate‐vinyl imidazole) [m‐poly(EGDMA‐VIM)] beads were produced by suspension polymerization in the presence of magnetite Fe₃O₄ nano‐powder. The specific surface area of the m‐poly(EGDMA‐VIM) beads was found to be 63.1 m²/g with a size range of 150–200 µm in diameter and the swelling ratio was 85%. The average Fe₃O₄ content of the resulting m‐poly(EGDMA‐VIM) beads was 12.4%. The maximum binding capacities of the m‐poly(EGDMA‐VIM) beads were 32.4 mg/g for Cu²⁺, 45.8 mg/g for Zn²⁺, 84.2 mg/g for Cd²⁺and 134.5 mg/g for Pb²⁺. The affinity order on mass basis is Pb²⁺>Cd²⁺>Zn²⁺>Cu²⁺. Equilibrium data agreed well with the Langmuir model. pH significantly affected the binding capacity of the magnetic beads. Binding of heavy metal ions from synthetic wastewater was also studied. The binding capacities were 26.2 mg/g for Cu²⁺, 33.7 mg/g for Zn²⁺, 54.7 mg/g for Cd²⁺ and 108.4 mg/g for Pb²⁺. The magnetic beads could be regenerated up to about 97% by treating with 0.1 M HNO₃. These features make m‐poly(EGDMA‐VIM) beads a potential candidate for support of heavy metal removal under magnetic field.     

Zeolite-A沸石分子筛去除水体中重金属污染物

合成了一种成本低,制备工艺简单的沸石分子筛 Zeolite-A,并对其吸附重金属离子的性能以及吸附的最佳条件(包括溶液的 pH 值,金属离子的浓度以及吸附过程的时间等)作了系统研究.除了具有天然沸石的优越吸附性能之外,根据扫描电镜图可见合成的 Zeolite-A 沸石分子筛还具有洁净的晶体表面,均匀的粒度,规则的形状且不存在胶体或无定形物质的优点.根据试验,Zeolite-A 沸石分子筛的吸附效率随金属水合离子的半径的增加而减小.在所试验的金属离子[Fe(Ⅱ、Ⅲ),Cr(Ⅲ),Pb2 ,Mn2 ,Cu'2 ,Mg2 ,Zn2 ,Ni2 及Cd2 ]中,Pb2 的水合离子半径最小,故其吸附效率最高,且随溶液 pH 的升高和吸附过程时间的增加,Pb2 的吸附效率也随之增加.试验中,所用金属离子的浓度为 2×103mg·L-1.在此条件下,Pb2 的吸附率达 99.6%,合成的 Zeo-lite-A 沸石分子筛可用于清除水体中重金属离子的污染.用过的 Zeolite-A 沸石分子筛置于0.1 mol·L-1 HCl 中浸泡可使重金属离子从沸石上解吸.     

电感耦合等离子体质谱法(ICP-MS)测定土壤中的重金属元素

采用电感耦合等离子体质谱法(ICP-MS)测定了国家标准土壤样品中的部分重金属元素(Cd,Cu,Pb,Zn,Cr,Ni,Mo)的含量,其测定值与推荐值相符,准确度符合国家标准要求。各元素方法的检出限满足要求,相对标准偏差(RSD)介于0.91%~4.3%,加标回收率介于94%~106%。方法简便快速,结果准确,可以运用于大批量地质样品中的部分重金属元素含量的同时测定。     

冲积平原区土壤中重金属元素的存在形态分析

采用0.1mol／L氢氧化钠浸提腐殖酸的方法,将土壤中的腐殖酸及与腐殖酸结合的重金属元素分离出来;分别用分光光度法、原子荧光光谱法、等离子质谱法测定样品中腐殖酸及重金属元素的含量;初步测定结果显示：与腐殖酸结合的重金属元素是冲积平原区表层土壤中重金属元素的1种重要存在形态,而且可能是土壤中重金属污染元素主要的存在形式。     

Microwave-Assisted Graft Copolymerization of Cellulosic Fibers for Removal of Heavy Metal Ions from Aqueous Solution

Functional materials obtained from cellulosic biofibers have gained attention due to the growing demand for them in the field of wastewater remediation. In view of the technological significance of functionalized cellulosic biofibers in wastewater treatment, the present study is a green approach to functionalized cellulosic fibers through graft copolymerization under microwave irradiation. The grafted cellulosic polymers were subsequently subjected to heavy metal ion adsorption studies in order to assess their application in wastewater remediation. The effects of pH, contact time, temperature, and metal ion concentration were studied in batchwise adsorption experiments. The Langmuir, Freundlich, and Tempkin models were used to show the adsorption isotherms. The maximum monolayer capacities, q _m. calculated using the Langmuir isotherm for Zn²⁺, Cd²⁺, and Pb²⁺ were found to be 37.79, 69.68, and 96.81 mg/g respectively. The thermodynamic parameter ΔH° and ΔG° values for metal ion adsorption on functionalized cellulosic fibers showed that adsorption process was spontaneous as well as exothermic in nature.     

土壤重金属污染来源及其解析研究进展

土壤重金属污染问题是环境和土壤科学研究者关注的热点问题。对土壤重金属污染物来源的鉴别是准确、有效控制和治理污染源的前提。根据近年来国内外对土壤重金属污染的相关研究报道,综述了土壤中污染物的工业、农业和交通因子三大主要来源,重点阐述了目前解析土壤重金属污染来源所运用的化学形态研究、剖面分布、同位素示踪、空间分析和多元统计等方法,并就存在的问题和今后的研究重点进行了总结。     

活化污泥强化工艺对重金属的去除效果研究

重点研究了活化污泥法强化一级处理对城市污水中重金属离子的去除效果。以实际生活污水和Cd、Cu、Zn、Cr6+、Pb、Mn六种城市污水中常见的重金属离子配水,采用活化污泥法的正常工艺条件,发现这几种金属离子去除的难易顺序为:Cd>Pb>Cu>Zn>Mn>Cr6+。水中的重金属离子与有机物间存在竞争吸附作用,共存时双方的去除效果都有所下降,但对Cd、Pb来说,有机物的存在则可以提高其去除效果。     

城市灰尘重金属含量对城市土壤重金属的影响--以金华市为例

为系统了解城市重金属污染特性,采集了金华市不同功能区的城市灰尘与城市土壤样品,获得重金属含量,并对数据进行了统计分析。结果表明：（1）灰尘中重金属含量均高于土壤,含量最高的 Mn,平均质量分数为770．62 mg/kg,其次为 Zn,为696．72 mg/kg。土壤中 Mn 元素质量分数最高,为537．60 mg/kg。（2）灰尘、土壤中重金属均为中等变异,且土壤变异程度高于灰尘,说明土壤中的重金属受外界扰动更大。（3）城市灰尘和土壤中 Zn 元素表现为显著正相关,说明其对土壤有影响, Cu、 Pb 和 Mn 表现为正相关, Nb 基本不相关, Cr 为负相关,但相关性均不显著。     

长沙市公园土壤重金属调查与评价

根据对长沙市公园土壤的重金属含量测定结果,采用内梅罗综合污染指数对其进行了评价,并运用相关分析、聚类分析进行了统计分析。研究结果表明,岳麓山公园、烈士公园土壤重金属含量较低,月亮岛土壤重金属含量较高。通过内梅罗综合污染指数评价,认为岳麓山公园土壤属于安全级别,未发生重金属污染;烈士公园土壤中Cr、Hg、Cd属轻污染,其余重金属无污染;月亮岛中土壤重金属污染相对严重,其中Zn、Cd属重污染。通过相关分析表明,与pH值呈正相关的为Cr、Zn、Pb、As;聚类分析研究表明,在距离为20分为两大类Cr、Zn;Hg、Cd、Cu、As、Pb、pH。     

测定土壤中重金属元素时前处理方法的改进

建立了一种微波消解前处理技术的半消解法消解样品,采用原子吸收光谱法和原子荧光光谱法同时测定土壤中主要重金属元素铜、锌、镉、砷、汞的方法,检测土壤标准物质GSS-3、GSS-5、GSS-20,结果显示测定均值在标准差允许范围内,相对标准偏差小于8.5%(n=4),是土壤重金属元素快速检测的可选方法。     

Oxidized Biomass and Its Usage as Adsorbent for Removal of Heavy Metal Ions from Aqueous Solutions

Nowadays, very coarse wool fibers are considered waste biomass and are discarded at random or burned. Therefore, it is of actual interest to valorize coarse wool fibers as utile products. In this sense, we report herein an environmentally-friendly process for the preparation of a new material based on oxidized wool fibers and designed for efficient adsorption of heavy metals from wastewater. The morphology and the structure of the obtained product were characterized by scanning electron microscopy (SEM) coupled with an X-ray energy-dispersive module (EDX) and by Fourier-transform infrared spectroscopy (FTIR). Likewise, the performances of the oxidized wool fibers for the adsorption of heavy metal cations (Cu²⁺, Cd²⁺, Pb²⁺) from aqueous solutions were tested. The adsorption kinetics data were analyzed by applying the pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models. The equilibrium of the adsorption process was investigated by using the Freundlich and Langmuir isotherm models. According to the Langmuir isotherms registered at 300 K, the maximum adsorption capacities of the oxidized wool were found to increase from Cu²⁺ (9.41 mg/g) and Cd²⁺ (10.42 mg/g) to Pb²⁺ (30.71 mg/g). Consequently, the removal efficiency of metal ions was found to vary in the range of 96.8–99.7%. The thermodynamic parameters (e.g., enthalpy, entropy, and Gibbs free energy) were calculated and discussed.     

Electrochemical Treatment of Heavy Metal‐containing Wastewater with the Removal of COD and Heavy Metal Ions

The use of electricity to treat water was employed for the first time in the UK a century ago, and since then has been considered a highly reliable method for wastewater treatment. In recent years, the demand for hydrogen gas as a valuable, clean energy source has increased considerably; from this point of view, the electrolysis of wastewater can meet the demand for energy during the process of treating wastewater. In this work, wastewater containing heavy metal ions has been treated by an electrochemical method which not only decreased the chemical oxygen demand value and lowered the number of heavy metals ions but also generated hydrogen throughout the process. A series of experiments were performed under optimum conditions of selected electrode materials, pH values, supply power, and working time. The results obtained indicate that by controlling the key factors of the process, a practical method can be achieved for wastewater treatment which also produces a noticeable amount of green energy. Differential pulse voltammetry measurements were used to determine the properties of an industrial wastewater source before and after treatment, while scanning electron microscopy and energy dispersive X‐ray spectroscopy were applied to investigate the proficiency of the electrode material.     

辐射诱导合成水凝胶及其处理重金属废水的研究进展*

水凝胶是一种经适度交联而具有三维网络结构的新型功能高分子材料。制备水凝胶因操作简单、无须添加交联剂和引发剂等优点而受到关注。传统的处理重金属废水的方法或成本较高,或效率低,利用水凝胶处理重金属废水成为一种新的颇具潜力的方法。本文综述了辐射法制备水凝胶及其在重金属吸附去除方面的研究进展包括材料的制备、改性、去除重金属性能等方面的研究进展,并指出了水凝胶去除重金属的发展前景和今后的研究方向。     

Research on Heavy Metal Pollution in Soil within the Upper Reaches of Lancang River

为了解澜沧江中上游流域矿区的开采和利用对周围生态环境的影响因素,通过选择对该矿区中3种重金属污染物Pb、Cd、Mn进行了调查和实验.确定澜沧江中上游流域的相应采样面,通过湿消化法处理样品,原子吸收光谱法测定了重金属的含量,并作了重金属污染评价.结果表明,澜沧江中上游流域矿区土壤Cd平均值为21.89 mg/kg,超标率为100％,土壤中重金属含量由高到低为Cd,Mn,Pb,重金属之间相关性不显著(P＞0.05).研究区土壤已经被严重污染,单项污染指数由高到低为Cd(21),Pb(0.87),Mn(0.81).可见澜沧江中上游流域矿区土壤中Pb、Cd、Mn的污染已经呈现出了危害人群健康的趋势,其中Pb、Cd污染最严重,对于重金属污染应采取综合治理措施.     

Preparation and Characterization of Ceramic Hollow Microspheres for Heavy Metal Ion Removal in Wastewater

Ceramic hollow microspheres (CHMSs) were prepared to use as supports for the removal of heavy metal ions from industrial waste-water. A water extraction sol–gel technique was used to prepare porous CHMS by extracting water from an emulsion of LUDOX (silica colloid; SiO₂, Aldrich Co.) and 2-ethyl-1-hexanol. Experiments were conducted to control pore size, wall thickness, and separation yield by examining the ratio of precursors (LUDOX and 2-ethyl-1-hexanol), catalyst (NH₄OH), sintering temperature, surfactant (SPAN 80), extractant (n-butanol), stirring speed, and concentration of precursor (LUDOX). The results revealed that the optimum conditions were 20 ml of a 10 wt% solution of LUDOX, 10 ml of NH₄OH, a sintering temperature of 500°C, 0.4 ml of SPAN 80, 200 ml of n-butanol, and a stirring speed of 730 rpm/100 ml of 2-ethyl-1-hexanol. CHMSs were impregnated in Cyanex 272 and examined for their ability to remove heavy metal ions from a solution. Based on an experiment involving the removal of metal ions using CHMSs that were prepared under optimum conditions, Zn ion was removed at a level of 0.354 mmol/g at pH 4, which was about twice the adsorption capacity of CHMSs prepared by Wilcox (Mater. Res. Soc. Symp. Proc.346, 201 (1994)).     

Poly-L-Histidine Attached Poly(glycidyl methacrylate) Cryogels for Heavy Metal Removal

Poly-L-histidine immobilized poly(glycidyl methacrylate) (PGMA) cryogel discs were used for the removal of heavy metal ions [Pb(II), Cd(II), Zn(II) and Cu(II)] from aqueous solutions. In the first step, PGMA cryogel discs were synthesized using glycidyl methacrylate (GMA) as a basic monomer and methylene bisacrylamide (MBAAm) as a cross linker in order to introduce active epoxy groups through the polymeric backbone. Then, the metal chelating groups are incorporated to cryogel discs by immobilizing poly-L-histidine (mol wt ≥ 5000) having poly-imidazole ring. The swelling test, fourier transform infrared spectroscopy and scanning electron microscopy were performed to characterize both the PGMA and poly-L-histidine immobilized PGMA [P-His@PGMA] cryogel discs. The effects of the metal ion concentration and pH on the adsorption capacity were studied. These parameters were varied between 3.0–6.0 and 10–800 mg/L for pH and metal ion concentration, respectively. The maximum adsorption capacity of heavy metal ions of P-His@PGMA cryogel discs were 6.9 mg/g for Pb(II), 6.4 mg/g for Cd(II), 5.6 mg/g for Cu(II) and 4.3 mg/g for > Zn(II). Desorption of heavy metal ions was studied with 0.1 M HNO₃ solution. It was observed that cryogel discs could be recurrently used without important loss in the adsorption amount after five repetitive adsorption/desorption processes. Adsorption isotherms were fitted to Langmuir model and adsorption kinetics were suited to pseudo-second order model. Thermodynamic parameters (i.e. ΔH° ΔS°, ΔG°) were also calculated at different temperatures.     

澜沧江中上游流域矿区土壤重金属含量的调查

为了解澜沧江中上游流域矿区的开采和利用对周围生态环境的影响因素,通过选择对该矿区中3种重金属污染物Pb、Cd、Mn进行了调查和实验。确定澜沧江中上游流域的相应采样面,通过湿消化法处理样品,原子吸收光谱法测定了重金属的含量,并作了重金属污染评价。结果表明,澜沧江中上游流域矿区土壤Cd平均值为21.89 mg/kg,超标率为100%,土壤中重金属含量由高到低为Cd,Mn,Pb,重金属之间相关性不显著(P>0.05)。研究区土壤已经被严重污染,单项污染指数由高到低为Cd(21),Pb(0.87),Mn(0.81)。可见澜沧江中上游流域矿区土壤中Pb、Cd、Mn的污染已经呈现出了危害人群健康的趋势,其中Pb、Cd污染最严重,对于重金属污染应采取综合治理措施。     

BTX Removal from Polluted Water Through Bioleaching Processes

In this study, benzene, toluene, and xylenes (BTX) removal from contaminated water by physical, chemical, and biological processes was studied. Results showed that air sparging in polluted water can reduce monoaromatic compounds from 140,000 to about 5 microg/l in only 1 h process with a gassing rate of 0.33 VVM. This method cannot be considered as a green technology as pollutants are only transferred from the liquid phase to the gas phase The ultimate objective of this research was thus to evaluate the efficiency of a strategy involving BTX adsorption by granular-activated charcoal (GAC) and subsequent regeneration of this support by a bioleaching process. Analysis of such processes requires the building of analytical tools able to accurately determine the contents of the contaminants in samples containing biomass to make possible the calculation of reliable material balances. Current investigation showed that BTX are readily trapped by GAC particles with low further release in the liquid medium whereas they remain at least partially available for in situ biodegradation. BTX adsorption onto the GAC was shown to reach maximum solute retention close to 350, 250, and 150 (as mg/g GAC) for xylenes, toluene, and benzene, respectively. This approach, which could afford efficient biological active carbon regeneration, is very promising for the removal of BTX compounds from water without any further environment damage.