微污染水源水中重金属镉的去除

针对我国水源水中微量重金属污染特点,在不改变常规给水处理工艺前提下,提出了用水合二氧化锰去除饮用水中的微量重金属镉污染物的强化混凝工艺。采用硫代硫酸盐与高锰酸盐经氧化还原反应生成的水合二氧化锰处理含镉水源水,系统讨论了pH、浊度、腐殖酸等水质参数对水合氧化锰混凝除镉效能的影响;采用XRD、XPS技术并结合投射电镜技术对水合二氧化锰粒子的物相晶型、表面组成及水中形态进行了表征;采用透光脉动检测技术对水合二氧化锰絮凝的全过程进行了研究,把微观的絮体结构与形态观测同宏观的混凝现象结合起来进行综合分析,试图探讨水合二氧化锰混凝去除水中重金属镉的可能机理和特点。结果表明：水合二氧化锰为表面积大、吸附力强的非晶形胶体,对溶解态隔和吸附态镉均表现了优异去除能力,其去除金属镉的机理可能是依靠专属吸附、静电吸附以及网捕卷扫综合作用的结果。水合二氧化锰能够很有效去除水源水中的微量镉,并能使出水满足饮用水水质标准。     

微污染水源水中重金属镉的去除

针对我国水源水中微量重金属污染特点,在不改变常规给水处理工艺前提下,提出了用水合二氧化锰去除饮用水中的微量重金属镉污染物的强化混凝工艺。采用硫代硫酸盐与高锰酸盐经氧化还原反应生成的水合二氧化锰处理含镉水源水,系统讨论了pH、浊度、腐殖酸等水质参数对水合氧化锰混凝除镉效能的影响;采用XRD、XPS技术并结合投射电镜技术对水合二氧化锰粒子的物相晶型、表面组成及水中形态进行了表征;采用透光脉动检测技术对水合二氧化锰絮凝的全过程进行了研究,把微观的絮体结构与形态观测同宏观的混凝现象结合起来进行综合分析,试图探讨水合二氧化锰混凝去除水中重金属镉的可能机理和特点。结果表明:水合二氧化锰为表面积大、吸附力强的非晶形胶体,对溶解态隔和吸附态镉均表现了优异去除能力,其去除金属镉的机理可能是依靠专属吸附、静电吸附以及网捕卷扫综合作用的结果。水合二氧化锰能够很有效去除水源水中的微量镉,并能使出水满足饮用水水质标准。     

水合二氧化锰混凝去除水中微量金属镉

以实验室配水和松花江水为本底,考察了高锰酸钾还原法制备的水合二氧化锰对水中的微量重金属镉的混凝去除效能,探讨了水体pH值、浊度等对镉去除效果的影响以及水合二氧化锰去除水中重金属镉的机理.结果表明:水合二氧化锰对水中的微量镉具有显著的去除作用,3mg/L的水合二氧化锰对实验室配水和松花江水中镉的去除率达95%以上,是一种非常有效的去除水源水中微量镉的水处理药剂.     

水合MnO_2强化FeCl_3共沉降去除水中微量Cd(Ⅱ)

采用烧杯混凝实验,分别以实验室配水和松花江水为本底,研究了水合二氧化锰强化三氯化铁共沉降去除水中微量镉的效能。详细探讨了影响水合二氧化锰强化三氯化铁共沉降去除水中微量镉的主要因素。结果表明:两种水质条件下,水合二氧化锰均可强化FeCl3混凝去除水中的微量镉,镉的去除率明显高于单纯FeCl3混凝。水体pH值、浊度、腐殖酸等水质参数对于水合二氧化锰强化三氯化铁共沉降去除水中微量镉的效能有不同程度的影响。其中水体pH值对水合二氧化锰强化三氯化铁共沉降去除水中微量镉的影响十分显著,Cd(Ⅱ)的去除效果随着水体pH增加显著升高。     

2,6-二甲酰基-4-甲基苯酚的超声波催化合成

在超声波辐射下，市售二氧化锰能将2，6－二羟甲基－4－甲基苯酚氧化成2，6－二甲酰基－4－甲基苯酚，其反应条件温和，易于操作，且反应速率快，收率也较高。     

水合二氧化锰去除水源水中有机污染物的初步实验研究

为了探讨水合二氧化锰对于实际水源水中有机污染物的去除效果,通过实验室烧杯混凝试验,以松花江水源水为研究对象,以高锰酸盐指数（CODMn）、DOC、UV254为指标,研究了高锰酸钾还原法制备的水合二氧化锰对实际水源水中有机污染物的去除效果,并对水合二氧化锰去除有机物的机理进行了初步探讨。结果表明：当水合二氧化锰投加量很低时（1～3mg／L）,其对松花江水源水中有机污染物的去除已很显著,并且CODMn、DOC、UV254三种指标具有良好的相关性。由此得出结论：与传统混凝剂相比,该种水合二氧化锰表现了良好的去除实际水源水中有机污染物的效能。实验结论对于水处理工程实际具有重要意义。     

高锰酸钾复合药剂对水中邻氯酚去除效能的研究

本文以水中的邻氯苯酚为研究对象,在实验基础上,考察了高锰酸钾及高锰酸钾复合药剂对纯水中微量邻氯酚的去除效果,用可见分光光度计分析,对二者的除酚效果进行了对比。结果表明:高锰酸钾复合药剂对水中微量邻氯酚具有较好的去除能力。同时还考察了水样pH值,高锰酸钾及其复合药剂投加量,反应水温,反应时间等因素对邻氯酚去除效果的影响。     

活性炭对水中2，4-二氯酚的吸附研究

以活性炭作为去除水中2，4-二氯酚的吸附剂，考察了振荡时间、水样pH值对吸附效果的影响，采用Langmuir和Fmundlich模式对吸附等温线作了线性拟合，结果表明2，4-二氯酚在活性炭上的吸附可用Langmuir和Freundlich较好地描述，吸附呈单分子层形式且易于进行，活性炭对2，4-二氯酚吸附性能良好，吸附剂易于再生。     

Fe~(3+)和漆酚催化过氧化氢对单取代苯的氧化

本文研究了 Fe~(3+)和漆酚催化 H_2O_2氧化单取代苯的产物。结果表明,硝基苯、苯酚和苯甲酸已被氧化成相应的酚;而在甲苯、氯代苯和溴代苯的反应体系中未检测到酚产物。     

水合二氧化锰混凝去除腐殖酸的效能研究

为了进一步探讨水合二氧化锰对于水中污染物的去除效能,采用杯罐混凝试验,以腐殖酸配制的水样为研究对象,以CODmn、TOC、UV254为指标,考察了高锰酸钾还原法制备的水合二氧化锰对腐殖酸的去除效能,并对水合二氧化锰去除有机物的机制进行了初步探讨。结果表明：当水合二氧化锰投加量为6mg·L^-1时,CODmn的去除率为15．25％,TOC的去除率为24．07％,UV254的去除率为38．0％。由此得出结论：与传统混凝剂相比,该水合二氧化锰表现出良好的去除腐殖酸及UV254的效能。     

Removal of Phenolic Pollutants from Water Utilizing Mangifera indica (Mango) Seed Waste and Cement Fixation

Abstract

A process for the removal of two chlorophenols (2-chlorophenol and 2,4-dichlorophenol) from water using surface modified mango seed waste by adsorption process followed by cement fixation of the phenols-laden adsorbent is investigated. The two main objectives of this study were to develop efficient adsorbent utilizing mango seed waste by physiochemical activation and to an environmentally-friendly disposal of phenols-laden adsorbent into cement by a fixation process. The results of the present study reveal that the modified mango seed adsorbent showed an efficient adsorption potential for chlorophenols removal from water. The maximum adsorption potential of modified mango seed adsorbent for 2-chlorophenol and 2,4-dichlorophenol was 40.6 and 72.3 mg g^?1, respectively at 25°C. Adsorption kinetic data of chlorophenols adsorption on mango seed adsorbent could be described more favorably by a pseudo-second-order kinetic model. After the adsorption studies, the phenol-laden adsorbent was immobilized in cement for its ultimate disposal. Leachates from the fixed phenols-laden adsorbent exhibit phenols concentrations lower than the drinking water standards. Results from this study suggest the potential utility of agricultural wastes as one of the most promising activated carbon precursors for phenols removal from water and wastewater and the safe disposal of phenol-laden adsorbent into cement by fixation process.     

Removal of Chlorophenols from Aqueous Solution by Anion-Exchange Resins

Abstract

The effects of pH value and chloride ion concentration on the removal of chlorophenols from aqueous solutions by Purolite A-510 resin [macroreticular polystyrene-divinylbenzene resin with R(CH₃)₂(C₂H₄OH)N⁺ group] are discussed by the species distributions of chlorophenols. Those chlorophenols include phenol, 2-chlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol. The investigations showed that the chlorophenols could be removed effectively at alkaline conditions where the ion-exchange reaction was dominant. Also, the removal of chlorophenols increased with the number of chlorine atoms on the chlorophenols. The removal of chlorophenols via the ion-exchange reaction was hindered by the presence of chloride ions. The effect of chloride ions, however, was diminished in acidic solutions where the adsorption reaction was dominant. The proposed equilibrium model, which considers both adsorption and ion-exchange reactions, adequately describes the sorption behavior of chlorophenols. The partition constants of the protonated chlorophenols can be estimated from the octanol/water partition coefficients of the phenolic compounds.     

煤气洗涤废水除酚脱氮技术研究

本文采用吸附树脂NDA-99和脱氮剂DN-17分别去除煤气洗涤废水中的酚类物质和氨氮。结果表明,处理后的出水挥发酚质量浓度<5mg/L,去除率>98%,总酚质量浓度<70 mg/L,去除率>90%。氨氮质量浓度<15mg/L,去除率>98%,BOD5/COD为0.65。该处理工艺可回收粗酚和(NH4)2SO4,是一项具有环境效益和经济效益的技术。     

高锰酸钾复剂对混凝时苯酚的强化去除效应

通过对含酚水样采用高锰酸钾复剂预氧化,强化常规的混凝处理,分析了高锰酸钾复剂对混凝除酚的强化效应,结果表明:高锰酸钾复剂投加量为3mg/L时,苯酚的去除率比单纯使用聚合氯化铝时高70%以上。机理分析表明:高锰酸钾复剂的强化混凝作用主要是基于高锰酸钾氧化和中间产物新生态水合二氧化锰等的催化氧化的综合作用引起的。     

Preliminary Investigation of Manganese-Catalyzed Ozonation for the Destruction of Atrazine

A preliminary experimental study conducted with a conventional bubble ozonation contactor column has shown that small amounts of Mn(II) greatly enhanced the destruction of atrazine by ozone. There is an inversely linear relationship between the dosed Mn(II) concentration and the residual ozone concentration at a specific reaction time. The ozone transfer efficiency into water is greater with the increase of Mn(II) dosage. Hydrous manganese dioxide prepared by reacting permanganate with manganese sulfate, also was shown to be effective in catalyzing the destruction of atrazine by ozone. The efficiency of catalytic activity for the destruction of atrazine caused by preformed hydrous Mn(IV) is slightly lower than the case of Mn(II). A lower residual ozone value using manganese dioxide compared to the case of ozone alone suggests that ozone also may be decomposed by hydrous Mn(IV). However, a commercial MnO₂ did not show any catalytic activity for atrazine destruction. The very much greater degree of atrazine oxidation by manganese-catalyzed ozonation compared to ozone alone is speculated to be the result of the generation of highly oxidative intermediate species such as hydroxyl radicals during the reaction between ozone and manganese species.     

Ozonation of Substituted Phenols in Aqueous Solutions over CuO-Al2O3 Catalyst

The oxidation of aqueous solutions of substituted phenols, chlorophenols (CPs) and nitrophenols (NPs), at 21±0.5°C and atmospheric pressure, by ozone over a copper–alumina catalyst system was studied. The total disappearance of phenol compounds for 15 to 30 minute reaction times was observed. The presence of the catalyst increased the reaction rate, diminished the ozone consumption and caused an advanced degradation of phenols. A number of six by-products was identified by gas chromatography/mass spectrometry technique (GC/MS), with or without silylation. Based on the experimental data several mechanistic suggestions for the catalytic ozonation are made.