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。     

铁基材料活化过硫酸盐降解水中抗生素的研究进展

抗生素广泛应用于医药和养殖行业,排入水体中的抗生素严重威胁了生态安全和人体健康.目前,常规污水处理过程对抗生素降解效率较低,基于硫酸根自由基(SO₄^·-)的高级氧化技术逐渐成为水处理领域的研究热点之一.铁基材料廉价易得,在活化过硫酸盐（PS）降解水中抗生素领域展现出一定的应用前景.本文重点综述了几种典型铁基材料在活化PS降解水中抗生素的研究进展,分析了pH、重复使用性等影响铁基材料实际处理效果的因素,并对铁基材料活化PS的发展前景进行了展望,旨在为拓展铁基材料环境应用和阐明PS活化机制提供重要参考.结果表明:铁（氢）氧化物、零价铁（ZVI）和铁硫化物等铁基材料活化PS产生的SO₄^·-和羟基自由基（HO·）对抗生素降解起关键作用.与传统铁基材料相比,复合型铁基材料表现出更加优异的催化性能和稳定性.此外,高价铁和单线态氧也被证明对铁基体系催化降解抗生素起重要作用.现阶段缺乏考察铁基材料/PS体系降解实际水体中抗生素性能和机理的研究;同时,单原子铁催化剂等新型铁基材料活化PS降解抗生素的性能及机制也有待进...     

可见光驱动下罗丹明B自活化过硫酸盐降解双酚A

目前,过硫酸盐的常规活化方法研究已经逐步成熟,但因成本过高或催化剂难以回收和二次污染等问题严重制约了其实际应用.本研究通过构建染料自活化体系,探讨了染料在活化过二硫酸盐发生自脱色以及降解其他污染物方面的应用潜能.结果表明,染料在可见光照射下可活化过二硫酸盐,不仅可以实现染料自脱色,而且可以降解其他污染物,罗丹明B与双酚A的降解率最高分别可达80%和90%.这一过程即包含了自由基反应途径,也包含了非自由基反应途径.体系中所产生的活性氧化物质包含：超氧自由基、硫酸根自由基、羟基自由基和单线态氧.染料自脱色效率与染料初始浓度、PS投加量和溶液初始pH等有关,同时,染料及其他污染物的初始浓度对其他污染物的降解有很大影响.这为过二硫酸盐的活化提供了一种经济环保的新思路,在未来染料废水的处理中拥有广阔应用前景.     

天然有机物活化过硫酸盐降解土壤有机污染物效果

采用模拟装置研究了不同大分子物质(多聚糖、腐殖酸、柠檬酸)联合亚铁离子和不同糖类(单聚糖、双聚糖、多聚糖)活化过硫酸盐氧化降解土壤中石油烃、多环芳烃的氧化效果和机制.结果表明,不同活化过硫酸盐对总石油烃和多环芳烃的降解效果依次为:腐殖酸联合亚铁离子多糖柠檬酸螯合铁多糖加亚铁离子双糖单糖CK对照组.其中,腐殖酸联合亚铁离子活化过硫酸盐对两种污染物的去除效率最高,分别达79.21%和79.89%,处理后土壤中石油烃的反弹含量最小,氧化效果最稳定.此外,腐殖酸联合亚铁离子和多糖活化过硫酸盐对难降解的高环多环芳烃均能实现很好的去除效果,降解效率分别达77.96%和84.37%,相比其他处理提高了14.37%~59.10%和20.78%~65.51%.腐殖酸联合亚铁离子活化处理后土壤氧化还原电位(Eh)最高(618~676 m V),多糖处理次之,表明大分子材料活化过硫酸盐的氧化性能最好,能高效去除土壤中有机污染物.     

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,...     

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。     

Fe-Cu/N共掺杂的ZIFs衍生材料活化过硫酸盐降解四环素

通过水热法制备了一种Fe、Cu双金属和N共掺杂的介孔催化材料FeCu-N-C,对其进行表征分析;开展FeCu-N-C活化过硫酸盐(PS)降解四环素(TC)的研究,考察了 FeCu-N-C投加量、TC浓度、PS浓度、pH和离子强度等因素对降解效果的影响.结果表明:在催化剂投加量为0.4g·L-1,TC初始浓度为40mg·...     

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。     

活化过一硫酸盐技术降解环境有机污染物的研究进展

高级氧化技术是一种以产生羟基自由基(·OH)和硫酸根自由基(SO₄?·)来降解环境有机污染物的技术. 近年来,通过活化过一硫酸盐(peroxymonosulfate, PMS)而产生SO₄?·的高级氧化技术受到了广泛关注. 与基于·OH的传统高级氧化技术相比,基于SO₄?·的高级氧化技术具有氧化还原电位高、半衰期长、适用pH范围广和对污染物反应快速等优点. 本文从活化PMS方法的特点和性质出发,对目前活化PMS技术降解环境有机污染物的主要方法和活化机理进行了论述,活化方法包括过渡金属活化(均相和非均相)、碳质材料活化、碱性活化、热活化、辐射活化、电解活化等,活化PMS的机制是通过活化方法使其分子结构中的O—O键发生断裂,从而使PMS分解形成SO₄?·或其他的活性物质. 此外,分析了活化PMS降解环境有机污染物的主要影响因素,其中影响均相系统PMS活化的因素包括过渡金属剂量、pH和水中阴离子等,过量的PMS和过渡金属可能成为SO₄?·的抑制剂,pH不仅对氧化剂分解产生自由基起着关键作用,还影响过渡金属种类的形成及其与氧化剂反应的有效性,而水中阴离子会与有机化合物竞争和SO₄?·发生反应. 最后,提出未来研究重点应在开发稳定高效活化PMS的金属氧化物、碳质材料,以及使用多种处理技术协同作用上,同时应加强对活化PMS技术降解有机污染物体系的降解产物和毒性分析的研究.      

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.     

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.     

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.     

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.     

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.     

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.     

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.     

Effect of sorbed and desorbed Zn(Ⅱ) on the growth of a green alga (Chlorella pyrenoidosa)

Toxic effect of Zn(Ⅱ) on a green alga (Chlorella pyrenoidasa) in the presence of sepiolite and kaolinite was investigated.The Zn-free clays were found to have a negative impact on the growth of C.pyrenoidosa in comparison with control samples (without adding any clay or Zn(Ⅱ)).When Zn(Ⅱ) was added,the algae in the presence of clays could be better survived than the control samples,which was actually caused by a decrease in Zn(Ⅱ) concentration in the solution owing to the adsorption of Zn(Ⅱ) on the clays.When the solution system was diluted,the growth of algae could be further inhibited as compared to that in a system which had the same initial Zn(Ⅱ) concentration as in the diluted system.This in fact resulted from desorption of Zn(Ⅱ) from the zinc-contaminated clays,although the effect varied according to the different desorption capabilities of sepiolite and kaolinite.Therefore the adsorption and desorption processes of Zn(Ⅱ) played an important part in its toxicity,and adsorption and desorption of pollutants on soils/sediments should be well considered in natural eco-environmental systems before their risk of toxicity to aquatic organisms was assessed objectively.