微波诱导AC/Cu、AC/Fe催化非均相Fenton 反应催化降解垃圾渗滤液

采用活性炭载体负载Cu、Fe为催化剂,在微波诱导作用下,对垃圾渗滤液污染物进行降解。实验结果表明,活性炭负载金属前经适当浓度硝酸浸泡处理后,催化剂对COD去除率提高可超过15%,过高硝酸盐浓度对COD去除有不利影响;催化剂对COD去除率随Cu、Fe金属负载量增加呈先增加后降低的趋势,催化剂对Cu、Fe的最佳负载量分别为质量百分比2.11%和1.12%。对于AC-Cu体系,在初始pH=3,H2O2投加量为4.98×103mg/L,催化剂用量为5.0×103mg/L,420 W功率下微波辐射10 min时,垃圾渗滤液COD去除率可达到84.13%;对于AC-Fe体系,当H2O2投加量为0.33×103mg/L,催化剂AC-Fe用量为2.0×104mg/L,420 W功率下微波作用10 min时,垃圾渗滤液COD去除率为60.16%。分析2种催化剂对COD去除差异的原因,可能是催化剂AC-Cu表面单分子分布的阈值比AC-Fe高。降解液的pH值对AC-Cu体系、AC-Fe体系COD去除影响存在拐点,最高COD去除率点对应的降解液pH值为3。微波辐射功率较低时,体系COD去除率随辐射功率增加而增加;辐射功率较高时,高温下垃圾渗滤液中有机硫化物分解成小分子硫化物,对催化剂活性存在一定抑制作用。     

Environmental and Potential Health Effects of Growing Leafy Vegetables on Soil Irrigated Using Sewage Sludge and Effluent: A Case of Zn and Cu

Abstract

The use of sewage sludge and effluent as a source of nutrients and water for crop production is increasing worldwide. A study was conducted in 2001 at Pension farm (near Harare) to determine the effect of long term (>30 yrs) application of sewage sludge and effluent on Zn and Cu accumulation in top soil, uptake of these metals by lettuce (Lactuca sativa L.) and mustard rape (Brassica juncea L.), and dry matter yield. Application of sewage sludge/effluent significantly (p < 0.001) increased total Zn (13.7–1563.9 mg kg^?1) and Cu (2.5–133.3 mg kg^?1) in the top soil (0–20 cm depth) compared to the control. Sewage sludge/effluent addition significantly (p < 0.001) increased Zn uptake by both test crops, while Cu uptake was significant in the first crop of lettuce and the second crop of mustard rape. Based on the dietary patterns of poor urban households in Zimbabwe, the maximum possible intake of Cu will only constitute 40% the Maximum Daily Intake (MDI). The toxicological implications for Zn will however be more severe, exceeding the MDI by 77% through exposure by lettuce consumption and by 251% consumption of mustard rape. It was concluded that long-term addition of sewage sludge/effluent to soil at Pension farm had increased the concentration of Zn and Cu in top soil to levels that pose environmental concern. The consumption of leafy vegetables produced on these soils pose a health risk to poor communities that reside around the study site, especially children, through possible Zn toxicity.     

Electrochemical Monitoring of Methylparathion Degradation in an Acid Aqueous Medium in Presence of Cu(II)

Abstract

A study was undertaken to determine the effect of Cu(II) in degradation of methylparathion (o,o-dimethyl o, 4-nitrophenyl phosphoriotioate) in acid medium. Initial electrochemical characterization of Cu(II) and methylparathion was done in an aqueous medium at a pH range of 2–7. Cu(II) was studied in the presence of different anions and it was observed that its electroactivity depends on pH and is independent of the anion used. Methylparathion had two reduction signals at pH ≤ 6 and only one at pH > 6. The pesticide's transformation kinetic was then studied in the presence of Cu(II) in acid buffered aqueous medium at pH values of 2, 4, and 7. Paranitrophenol appeared as the only electroactive product at all three pH values. The reaction was first order and had k values of 5.2 × 10^?3 s^?1 at pH 2, 5.5 × 10^?3 s^?1 at pH 4 and 9.0 × 10^?3 s^?1 at pH 7. It is concluded that the principal degradation pathway of methylparathion in acid medium is a Cu(II) catalyzed hydrolysis reaction.     

微米Cu／Fe对污染土壤洗脱液中有机氯农药的降解

以表面活性剂TritonX-100（TX-100）为洗脱剂,某有机氯农药（organochlorinepesticides,OCPs）污染场地土壤为对象,七氯、氯丹和灭蚁灵为目标污染物,研究微米Cu／Fe双金属对污染土壤洗脱液中OCPs的降解效果。考察了洗脱液中OCPs初始浓度、洗脱液pH值、微米零价铁加入量和cu负载量对Cu／Fe去除OCPs效果的影响。结果表明,微米Cu／Fe可以有效的去除土壤洗脱液中目标污染物。当微米零价铁加入量为1．0g（25g／L）,cu负载量为1．0％,洗脱液pH值为6．89时,Cu／Fe对2号土壤洗脱液中七氯、γ-氯丹、α-氯丹和灭蚁灵的去除效果最好,去除率分别为100．0％、99．3％、80．8％和71．1％。洗脱液中OCPs初始浓度越低,微米零价铁加入量越大,Cu／Fe对OCPs去除率越高;偏酸性条件有利于Cu／Fe对γ-氯丹和灭蚁灵的去除,而α-氯丹在中性条件下去除效果最好;1号土壤和2号土壤洗脱液的最佳铜负载量分别为2．O％和1．0％。     

Transport of copper as affected by titania nanoparticles in soil columns

The effects of TiO₂ nanoparticles on the transport of Cu through four different soil columns were studied. For two soils (HB and DX), TiO₂ nanoparticles acted as a Cu carrier and facilitated the transport of Cu. For a third soil (BJ) TiO₂ nanoparticles also facilitated Cu transport but to a much lesser degree, but for a fourth soil (HLJ) TiO₂ nanoparticles retarded the transport of Cu. Linear correlation analysis indicated that soil properties rather than sorption capacities for Cu primary governed whether TiO₂ nanoparticles-facilitated Cu transport. The TiO₂-associated Cu of outflow in the Cu-contaminated soil columns was significantly positively correlated with soil pH and negatively correlated with CEC and DOC. During passage through the soil columns 46.6-99.9% of Cu initially adsorbed onto TiO₂ could be “stripped” from nanoparticles depending on soil, where Cu desorption from TiO₂ nanoparticles increased with decreasing flow velocity and soil pH.     

Dyella ginsengisoli LA-4吸附Cu2+特性及其动力学研究

研究一种新型吸附菌剂Dyella ginsengisoli LA-4(以下简称菌株LA-4)对Cu2+的吸附特性及其动力学,并利用表面响应法优化菌株LA-4对Cu2+的吸附条件.结果表明:(1)菌株LA-4的接种量、pH对Cu2+的吸附有重要的影响.(2)根据表面响应法 优化模型预测出菌株LA-4吸附Cu2+的最...     

固定化斜生栅藻净化畜禽废水中氨氮和磷的影响因素

为探讨Cu2+、p H和流速对固定化斜生栅藻去除畜禽废水中NH+4-N、TP效果的影响,在实验室条件下模拟实际污水处理过程,并采用正交实验方案对结果进行分析。结果表明低质量浓度Cu2+(0~0.05 mg/L)改善藻的净化效果,高质量浓度Cu2+(0.50~5.00 mg/L)抑制藻的净化效果;在p H较高的条件下(p H=9),固定化斜生栅藻的净化效果明显提高;流速对结果没有明显影响。通过正交实验,得出固定化斜生栅藻去除畜禽废水中NH+4-N、TP的优化条件如下:Cu2+质量浓度为0.05 mg/L,p H为9,流速为0.3 m/s。此时NH+4-N去除率为96.11%,TP去除率为97.53%。     

溶胶凝胶法制备铜催化剂及其稳定性的研究

介绍了利用溶胶凝胶方法制备铜系催化剂，并考察了制备过程中各个工艺参数对铜系催化剂稳定性的影响。通过优化催化剂的设计和制备方法，可有效地改善Cu^2＋的溶出问题，使该类催化剂具有广阔的应用前景。     

铜及其与四环素的联合暴露对斑马鱼胚胎的毒性效应

近年来工业和养殖业中铜和四环素的滥用,导致了一定程度的水环境污染问题。为探究铜与四环素对水生生物的毒害作用,选择斑马鱼作为受试生物,研究了铜及其与四环素的联合暴露对斑马鱼胚胎的毒性效应,并进一步探索了其中可能的致毒机制。结果表明:铜在低浓度下(10%致死浓度LC10=2.5μg·L~(-1),10%效应浓度EC_(10)=0.1μg·L~(-1))明显延迟了斑马鱼胚胎的孵化、卵黄囊吸收、头部、鱼鳔和体长等生长指标的发育,同时在心脏区域引起了明显的细胞凋亡效应。幼鱼体内总铜含量检测结果显示低浓度下铜的生物利用度相对更高。基因表达结果显示环境浓度的铜可能通过影响神经和心脏相关基因的表达引起斑马鱼胚胎的神经发育和心脏发育异常。铜和四环素的联合暴露实验结果表明二者的复合污染类型为拮抗作用,且两者相互作用可以形成络合物。综合以上结论,说明环境浓度的铜可能通过细胞凋亡、分子水平的变化等方式对水生生物的早期生长发育产生危害,如延迟生长发育、神经及心脏发育异常,另外铜可通过和四环素等环境中其他污染物的结合改变铜的生物有效性和毒性。     

水溶性有机物在土壤剖面中的分馏及对Cu迁移的作用

通过室内土柱试验研究了DOM在土壤剖面中的“分馏”作用,DOM在纵向运移过程中的穿透行为及对污染的红壤和潮土中重金属Cu溶出效果的影响.结果表明,绿肥和猪粪DOM经过土柱后极性都有所降低,在潮土上的降低幅度较大,分别为11.4%和10.72%;DOM能够明显地增加污染土壤中Cu的溶出,且这种作用效果与DOM及土壤的性质有关,绿肥DOM的作用效果比猪粪DOM的强,整个淋洗过程中潮土上Cu的平均溶出量是红壤上的4.37倍(绿肥DOM)和3.03倍(猪粪DOM);由于微生物对DOM的分解作用,降低了DOM对土壤中Cu的溶出效果.