碳载铁基双金属活化过硫酸盐降解有机污染物

过硫酸盐高级氧化技术因具有氧化性强、稳定性高、药剂易于运输等特点,被广泛应用于有机污染场地的修复中,在环境治理领域具有广阔的应用前景。通常过硫酸盐需要激活才能有效地去除有机物,碳载铁基双金属材料因碳材料的多孔结构和高比表面积可以提高金属的分散性,而且还可以吸附目标污染物,是一种能够高效活化过硫酸盐降解有机污染物的激活剂。该研究在关注碳载铁基双金属的制备方法的基础上,分析了碳载双金属活化过硫酸盐氧化体系的主要机制,探讨了影响碳载铁基双金属活化过硫酸盐体系降解效率的主要影响因素及碳载铁基双金属材料的稳定性,并进一步展望了碳载铁基双金属活化过硫酸盐体系降解有机污染物的研究方向和发展趋势。     

铁活化过硫酸盐原位修复有机污染土壤研究进展

原位化学氧化修复技术（in situ chemical oxidation,ISCO）是处理场地污染物的常用方法。过硫酸盐（S₂O₈2-）作为原位化学氧化技术使用的1种新兴修复剂,具有更加稳定、易传质、pH适用范围广的特点。通过光、热、过渡金属等条件可以对S₂O₈2-进行活化,分解产生SO₄-·。在分析过硫酸盐氧化机理时,介绍了不同活化方式对过硫酸盐氧化降解有机污染物的影响,重点阐述了不同铁活化方式活化过硫酸盐在有机污染土壤的研究现状,同时对存在的问题及发展趋势进行了展望。     

基于硫酸自由基的高级氧化技术研究及应用进展

由于硫酸自由基(SO4-.)具有很高的氧化还原电位,过硫酸盐(S2O82-)活化高级氧化技术作为一种新型氧化技术在环境工程领域具有巨大应用潜能。介绍了热活化、光活化、过渡金属离子三种活化过硫酸盐产生SO4-.的方式,在环境保护方面的现状研究与应用进展,主要涉及受有机污染土壤和地下水的修复、难降解有机废水和废气的处理,阐述了SO4-.高级氧化技术处理各种有机污染物的机理,指出了基于SO4-.的高级氧化技术在处理应用中存在的局限性和未来发展方向。     

铁基双金属催化剂活化过硫酸盐去除水中抗生素研究进展

近年来,抗生素残留物在多种水体中被普遍检出,对水生态环境和人类健康造成严重威胁.基于活化过硫酸盐高级氧化作用去除水中抗生素污染物,以其氧化性强、选择性高和pH适用范围宽等特点成为研究热点.低成本、高稳定性和催化性能优异的铁基双金属材料能有效活化过硫酸盐,它弥补了单一铁元素活化剂易失活、效率低和容易产生二次污染等缺陷.针对尖晶石铁氧体、铁基层状双金属氢氧化物和铁基普鲁士蓝类似物3种典型铁基双金属催化剂,开展其活化过硫酸盐降解抗生素的研究分析,系统讨论了铁基双金属活化过硫酸盐的几种内在驱动机制,并分别对自由基、单线态氧和高价金属的产生,电子转移和过硫酸盐直接氧化过程进行了梳理.最后,总结了活化过硫酸盐技术处理氟喹诺酮类、磺胺类、四环素类与β-内酰胺类抗生素等4种典型抗生素的一般降解途径,为今后研究铁基双金属催化剂及其改性、衍生物和复合物等在活化过硫酸盐技术中的应用提供参考.     

基于过硫酸盐的高级氧化工艺修复有机污染土壤的研究进展

基于硫酸根自由基的高级氧化工艺(sulfate radicals based-advanced oxidation processes, SR-AOPs)因其高效、经济且环境友好等特点,在有机污染土壤的修复领域受到越来越多的关注. SR-AOPs的原理是通过活化过硫酸盐(S₂O₈^2-,PS)产生以硫酸根自由基(SO₄·^-)为主的活性氧自由基将有机污染物氧化成CO₂、H₂O和无害或危害较小的化学物质.本文概述了影响SR-AOPs修复污染土壤的因素,重点总结了SR-AOPs在总石油烃(TPHs)、多环芳烃(PAHs)、多氯联苯(PCBs)、农药等污染土壤修复中的应用,分析了污染物特征、过硫酸盐和活化剂用量、土壤与溶液比等对污染物去除效率的影响,并讨论了SR-AOPs处理对土壤生态的影响.结果表明：活化方式、pH、土壤含水量、土壤有机质等因素会影响SR-AOPs对污染土壤的修复效果.热活化、微波活化、超声波活化、碱活化、基于铁基催化剂活化等...     

外场效应强化过硫酸盐氧化技术去除有机污染物的研究进展

环境中难降解有机物对生态环境及人体健康构成了巨大的威胁.近年来,外场效应活化过硫酸盐高级氧化技术在环境治理中得到了广泛研究.为进一步明确外场效应强化过硫酸盐活化技术的微观机制和污染物去除效能并拓宽其应用范围,综述了包括热场、US（ultrasonic,超声）场、电场、光场、磁场及压电场6类常见外场辅助过硫酸盐活化去除有机污染物的研究进展.结果表明:（1）热场、US场、电场及光场强化过硫酸盐活化技术去除污染物的效能、活化机理和实际应用价值已被进行详细的研究.（2）在上述场效应中,磁场仅应用于提高Fe⁰及相关复合物活化过硫酸盐的效果;而压电效应活化过硫酸盐技术作为新兴的技术手段,其相关的研究报告非常少.（3）目前的研究仍存在一些不足,如外场效应强化过硫酸盐活化技术的能源利用率、经济成本和实际应用潜能,以及降解过程中副产物的生态毒性等问题仍未进行深入的研究;压电强化过硫酸盐活化技术中压电材料和压电源的选择以及活化机理等内容依然存在空白;需解决多场耦合活化过硫酸盐技术存在的兼容性问题,其应用潜力也需进行评估.研究显示,外场效应强化过硫酸盐氧化技术具有高效的有机物去除能力,...     

外场效应强化过硫酸盐氧化技术去除有机污染物的研究进展

环境中难降解有机物对生态环境及人体健康构成了巨大的威胁.近年来,外场效应活化过硫酸盐高级氧化技术在环境治理中得到了广泛研究.为进一步明确外场效应强化过硫酸盐活化技术的微观机制和污染物去除效能并拓宽其应用范围,综述了包括热场、US（ultrasonic,超声）场、电场、光场、磁场及压电场6类常见外场辅助过硫酸盐活化去除有机污染物的研究进展.结果表明:（1）热场、US场、电场及光场强化过硫酸盐活化技术去除污染物的效能、活化机理和实际应用价值已被进行详细的研究.（2）在上述场效应中,磁场仅应用于提高Fe⁰及相关复合物活化过硫酸盐的效果;而压电效应活化过硫酸盐技术作为新兴的技术手段,其相关的研究报告非常少.（3）目前的研究仍存在一些不足,如外场效应强化过硫酸盐活化技术的能源利用率、经济成本和实际应用潜能,以及降解过程中副产物的生态毒性等问题仍未进行深入的研究;压电强化过硫酸盐活化技术中压电材料和压电源的选择以及活化机理等内容依然存在空白;需解决多场耦合活化过硫酸盐技术存在的兼容性问题,其应用潜力也需进行评估.研究显示,外场效应强化过硫酸盐氧化技术具有高效的有机物去除能力,...     

生物炭基非金属过硫酸盐活化剂的开发与应用

生物炭驱动的过硫酸盐高级氧化技术近几年来受到了环境科学界的广泛关注.本文对当前生物炭基非金属过硫酸盐活化剂开发过程中采取的调控措施与改性手段进行了总结,汇总了生物炭基过硫酸盐高级氧化技术在难降解有机污染物削减方面的应用,同时阐述了生物炭活化过硫酸盐的机理,展望了生物炭基过硫酸盐活化剂未来的发展方向与挑战.     

过硫酸盐在污泥处理中的应用

污水处理厂剩余污泥处理问题已成为影响中国城市化进程健康发展的重要因素。为提高剩余污泥的脱水及厌氧消化性能,需对其进行预处理,以破坏污泥絮体结构,强化其脱水性能;释放胞内物质,改善其厌氧消化性能。过硫酸盐具有氧化能力强和易于活化等特性,国内外学者将其应用于污泥处理中,发现过硫酸盐活化后产生的SO_4~-·可以有效破解污泥絮体结构,导致污泥絮体内水分和污泥细胞内含物的释放。利用SO_4~-·破解污泥絮体,以提高污泥的脱水性和消化性能是一种较为可行的污泥处理方案。该文尝试梳理已发表的关于使用过硫酸盐处理污泥的研究,对过硫酸盐的活化方法及其在污泥处理中的作用机理和处理效果进行总结,探讨其在处理城市剩余污泥方向的应用前景。     

化学氧化法修复TPH污染土壤的效果比较及工艺研究

以TPH污染土壤为研究对象,研究了不同化学氧化体系对TPH污染土壤的修复效果及影响因素。研究表明:Fenton、类Fenton及碱活化过硫酸盐3个体系都对TPH污染土壤有较好的修复效果。柠檬酸的加入改善了Fenton体系的催化作用,类Fenton体系降解效果最佳。TPH在类Fenton及碱活化过硫酸盐体系中的降解符合准一级反应动力学,提高H₂O₂、柠檬酸和过硫酸盐的浓度均有利于TPH的降解。强化混合、分次投加氧化剂及减小土壤粒径均可以提高TPH的降解效率,节约氧化剂用量。类Fenton体系中有效成分主要为·OH,碱活化过硫酸盐体系中除了·OH外,还存在SO₄-·或O₂-·等的作用,因此氧化剂利用率较高。     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.