常介孔型磁性离子交换树脂的制备及其效能——针对典型藻源含氮有机物

以甲基丙烯酸缩水甘油酯为单体,利用单体聚合法制备了介孔型磁性离子交换树脂(m-MIER),并在表征其基本性状的基础上,初步分析了其对典型藻源含氮有机物(藻蓝蛋白、氨基酸)的去除效能.为便于比较,研究过程中同步进行了磁性离子交换树脂(MIEX^®)的研究.研究结果表明,m-MIER是以氯为交换基团的介孔型材料,其孔径为2~60nm;与MIEX^®相比,m-MIER具有相似的湿视密度、粒径,更丰富的孔隙结构、更大的交换容量(1.15g/cm³, 150~200 μm, 0.1852cm³/g, 3.16mmol/g Vs 1.20g/cm³, 150~180 μm, 0.0184cm³/g, 2.23mmol/g);XPS图谱分析结果表明其内核成分主要为Fe₃O₄,且为季胺型阴离子交换树脂.针对藻源含氮有机物的去除结果表明,m-MIER对藻蓝蛋白、特定氨基酸的去除效果明显优于MIEX^®,且去除效果与氨基酸的种类显著相关.     

Efficient removal of heavy metals from electroplating wastewater using polymer ligands

Poly(hydroxamic acid)-poly(amidoxime) chelating ligands were synthesized from poly(methyl acrylate-co-acrylonitrile) grafted acacia cellulose for removing toxic metal ions from industrial wastewaters. These ligands showed higher adsorption capacity to copper (2.80 mmol?g⁻¹) at pH 6. In addition, sorption capacities to other metal ions such as iron, zinc, chromium, and nickel were also found high at pH 6. The metal ions sorption rate (t_1/2) was very fast. The rate of adsorption of copper, iron, zinc, chromium, nickel, cobalt, cadmium and lead were 4, 5, 7, 5, 5, 8, 9 and 11 min, respectively. Therefore, these ligands have an advantage to the metal ions removal using the column technique. We have successfully investigated the known concentration of metal ions using various parameters, which is essential for designing a fixed bed column with ligands. The wastewater from electroplating plants used in this study, having chromium, zinc, nickel, copper and iron, etc. For chromium wastewater, ICP analysis showed that the Cr removal was 99.8% and other metal ions such as Cu, Ni, Fe, Zn, Cd, Pb, Co and Mn removal were 94.7%, 99.2%, 99.9%, 99.9%, 99.5%, 99.9%, 95.6% and 97.6%, respectively. In case of cyanide wastewater, the metal removal, especially Ni and Zn removal were 96.5 and 95.2% at higher initial concentration. For acid/alkali wastewater, metal ions removing for Cd, Cr and Fe were 99.2%, 99.5% and 99.9%, respectively. Overall, these ligands are useful for metal removal by column method from industrial wastewater especially plating wastewater.     

Comparative effects of five chelating agents on testicular toxicity in mice induced by acute exposure to cadmium

The aim of this study was to develop new antidotes for cadmium (Cd) since this metal is known to produce mammalian toxicity. N-p-hydroxymethylbenzyl-D-glucamine dithiocarbamate (HBGD), N-benzyl-D-glucamine dithiocarbamate (BGD), diethyldithiocarbamate (DDTC), 2,3-dimercaptopropanol (BAL), and ethylenediamine-tetraacetic acid (EDTA) were studied for their ability to inhibit the adverse effects induced by Cd on mouse testes. The parameters examined included concentrations of Cd, calcium (Ca), iron (Fe), and zinc (Zn) in testes, lipid peroxidation (LPO) levels in testes, lactate dehydrogenase (LDH) activity in serum and reproductive ability of male mice. Mice injected intraperitoneally (ip) with CdCl₂ (2.5?mgCd?kg^?1) after 30?min or 24?h, were then injected ip with chelating agents (400?µmol?kg^?1). Cd increased the concentrations of testicular Ca, Cd, Fe, Zn, and LPO levels as well as the activity of LDH in serum. HBGD and BGD effectively prevented the increase in above indices, and improved the reproductive ability weakened by exposure to Cd. The results suggested that HBGD and BGD are more effective detoxificants in the case of testicular toxicity in mice induced by acute exposure to Cd.     

Synthesis and characterization of an ion exchanger based on tamarind kernel powder and its application for removal of some metal ions from industrial effluents

A resin synthesized from tamarind kernel powder possesses high selectivity for metal ions. Distribution coefficients for some metal ions has been determined by the batch method. The influence of pH on ion exchange capacity and K _d value of metal ions were studied. The resin has been characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, chemical composition and ion exchange capacity (IEC). The selectivity order is Pb²⁺?>?Cu²⁺?>?Fe²⁺?>?Zn²⁺?>?Ni²⁺. Removal of metal ions from the aqueous solution and from effluents of a steel mill has been studied.     

Chelant-assisted pulse flushing of a field Pb-contaminated soil

Laboratory experiments on a lead-contaminated soil were carried out to test the effects of chelant addition on metal leachability using column tests. Tests were aimed at studying metal mobilisation upon application of two different chelating agents (ethylenediaminetetraacetic acid [EDTA] and ethylenediaminedisuccinic acid [EDDS]). Column operation was arranged to simulate a flushing treatment in which the chelating agent is applied in a pulse mode to the soil for one bed volume, while deionised water was continuously introduced for the rest of the experiment. Two different concentrations (3 and 5 mmol·kg ^?1 respectively) of the two chelating agents and a control solution (deionised water) were tested in separate experiments; pH, total organic carbon and the total concentrations of Pb, Zn, Fe, Cd, Cu and Ni were monitored during each run. A seven-step sequential extraction procedure was used to evaluate metal partitioning and concentration in the contaminated soil after treatment as a function of depth. The results showed the effect of the nature of flushing solution on the hydraulic behaviour of the columns. Metal concentrations in the leachate increased considerably upon the application of chelants, thus indicating their suitability for metal extraction from contaminated soils. In view of full-scale application of soil flushing, particular concern should also be devoted to ensuring a homogeneous distribution of the solution within the contaminated area and an efficient collection of the exhausted extracting solution, as well as to recovering and recycling the chelating agent used.     

几种焦化废水深度处理技术的比较

分别采用Fenton试剂氧化法、固定床离子交换树脂吸附法和流化床磁性树脂吸附法对某焦化厂焦化废水生化工艺出水进行深度处理.试验结果表明:Fenton试剂氧化法处理后出水COD去除率最高达75.4％,色度去除率达89.1％;固定床离子交换树脂吸附法COD去除率为49.4％,色度去除率为96.5％;流化床磁性树脂吸附法COD去除率为58.2％,色度去除率为90.2％.Fenton试剂氧化法COD去除率较高,固定床离子交换树脂吸附法和流化床磁性树脂吸附法色度去除率较高.综合考虑,Fenton试剂氧化法具有更高的工程应用价值.     

土壤中重金属[S,S]-乙二胺二琥珀酸浸提及其对重金属形态分布的影响

采用螯合剂[S,S]-乙二胺二琥珀酸([S,S]-EDDS)对废弃矿区附近的农田土壤进行浸提,分析浸提前后残留土壤样品中重金属的形态.结果表明,[S,S]-EDDS对重金属元素的提取率在不同土壤之间有较大差异,对Cu的浸提率为13.4%-13.8%,对Pb的浸提率为2.28%-16.3%,对Zn的浸提率为2.73%-11.3%.[S,S]-EDDS在提取重金属的同时也造成了Fe和Mn的明显溶出,其中Fe的溶出率为0.090%-0.291%,Mn的溶出率为2.53%-6.31%,均远高于对照组.[S,S]-EDDS浸提后酸溶/可交换态金属含量的变化倚赖于金属种类,对于Cu和Zn,经[S,S]-EDDS浸提之后,其酸溶/可交换态含量远低于对照组;但对于Pb,经[S,S]-EDDS浸提之后,酸溶/可交换态含量略高于对照组.[S,S]-EDDS对Cu和Zn四种形态均有浸提作用,且对残渣态的影响小于其它形态.[S,S]-EDDS浸提导致土样中Cu和Zn残渣态比例上升,其它形态比例的变化则依赖于金属的种类以及土壤性质.     

树脂吸附法处理磺胺脒生产废水的工艺

针对磺胺脒生产废水的特点,本研究确定了采用树脂吸附法回收磺胺、进一步回收硝酸钠的工艺流程,探讨了树脂对磺胺吸附-解吸的最佳工艺条件.结果表明:DRHⅢ型大孔吸附树脂对磺胺具有良好的吸附-解吸效果,能将有机物和无机物很好地分离.经树脂吸附处理后,废水中COD去除率86%,硝酸钠回收率95%,磺胺回收率86%,其纯度达99.8%.在废水有效处理的同时实现了废物资源化,具有良好的环境效益和较高的经济效益.     

氨基酸生产工艺及环境状况分析

介绍以毛发为原料生产氨基酸的生产工艺及废水处理情况，分析了这种废物利用工艺取得的经济和环境效益。     

离子交换树脂处理含铬废水的研究

介绍了离子交换树脂处理含铬废水的原理,讨论了影响离子交换树脂处理能力的因素,通过pH值静态实验和流量动态实验找出了最佳反应条件.结果显示:离子交换树脂去除废水中六价铬是可行的,处理效果好.针对本次实验废水的最适合pH值为3,废水的最适合流量为3 BV/h.