超声波处理难降解有机物影响参数研究

考察了多种操作参数对多氯联苯、溴苯超声波降解的影响。结果表明，高频率、高声强、高流速、混合气体可以提高超声反应速率，358kHz下降解速率比20kHz提高了848％，34mL／min流速下比4．4mL／min提高了140％，参入Ar比单纯使用O2提高83%(+80％Ar)或66％(+50%Ar)。然而高声强也造成了较多的能量消耗。自由基清除剂的存在则较大地降低了超声反应速率，200mmol／LCO3^2-存在时反应速率下降了79％。     

超声波处理剩余污泥有机物、氮和磷的释放特性研究

以生活污水处理厂污泥为研究对象.采用超声波技术研究了污泥破解过程中有机物、氮和磷的释放规律.结果表明,在声能密度为0.167、0.330、0.500 W/mL的条件下,污泥中的有机物、氮和磷的释放均随超声时间而增加;破解后污泥释放出的有机物以分子量(MW)≤2 000的物质为主,且上清液BOD5/COD>0.33;所释放的氮以有机氮为主,其次是氨氮,污泥破解液COD/凯氏氮平均值为11,适合于生物法脱氮;污泥破解所释放的正磷酸盐约占污泥总磷质量的6.0%～18.2%.利用沉淀结晶法将其回收,可减轻原污水处理工艺的磷负荷.     

超声波降解水中的氯苯

考察了用超声波降解水中氯苯的可行性、动力学、产物和TOC变化。在 2 0kHz和 4 0W的超声波作用下 ,氯苯的一级降解常数为 0 0 5 /min。随着所加超声功率的增高 ,氯苯降解常数呈线性增加。 30min内超声脱氯效率达到 6 6 % ,TOC去除达到 4 3%。     

挥发性有机物低温等离子体降解的影响参数研究

作为一类重要的有机污染物,挥发性有机物的危害已引起了世界各国的广泛关注。以挥发性有机物代表物质苯为研究对象,考察了多种实验参数对苯降解特性的影响。在高频电源条件下,对于施加电压、电源频率及反应器参数（包括管径、有效长度、电极材料和电极直径）与苯去除率的关系进行了研究。结果表明,高施加电压、高电源频率有利于苯的降解。管径较小、有效长度较长、内电极直径较大、内电极材料为钨的反应器对于苯的去除效果明显。反应器参数与电源的匹配问题对于提高污染物去除率及节能降耗方面十分重要。     

处理难降解有机物的新型SBR反应器的发展

本文在分析ＳＢＲ 工艺特点的基础上,从反应器本身及ＳＢＲ 反应运行工序的设计两方面对处理难降解有机物新型ＳＢＲ 反应器的发展作了论述。分析认为ＳＢＲ 工艺将在中小型企业含难降解有机物工业废水处理中广泛应用。     

低温等离子体氧化水中难降解有机物研究

实验将介质阻挡放电与电晕放电组合在同一个反应器内,实验废水为直接大红染料溶液,将高压电极上通人50 Hz交流高压电,介质阻挡放电系统的电极间距为30 mm、电晕放电系统电极间距为25 mm、电源电压20 kV,利用常压空气中形成的雾化水电极介质阻挡放电/电晕放电低温等离子体及其活性基团作用于难降解有机物分子.实验分析了...     

过硫酸钠/钴离子/超声波协同降解酸性橙7

以酸性橙7（AO7）为目标污染物,研究了过硫酸钠（Na2S2O8）/钴离子（Co2+）/超声波（US）协同降解水体中AO7的过程及其降解机理,并分别考察了Na2S2O8初始浓度、AO7初始浓度、催化剂投加量和超声波功率对AO7降解率的影响。实验结果表明,过硫酸钠/钴离子/超声波协同工艺能有效的降解水中的酸性橙7。初始AO7浓度越低降解效果越好。超声功率在200~450 W之间时,AO7的降解率随着超声波功率的增大同样先升高后降低。在体系中加入乙醇和叔丁醇后明显抑制AO7的降解,证明该体系中主要氧化物种为硫酸根自由基（SO4-·）和羟基自由基（·OH）。     

超声波降解水溶液中对二氯苯

采用超声波降解含对二氯苯(p-DCB)的溶液,研究了p-DCB降解的动力学和影响因素.结果表明:(1)超声波降解水溶液中的p-DCB,随着p-DCB初始浓度的增加降解率减小;p-DCB的超声波降解反应符合表观一级动力学规律.(2)增大超声波频率和功率以及双频率联合使用可以增大p-DCB的降解率和一级反应速率常数.(3)弱酸性或中性环境更有利于p-DCB的降解进行.(4)反应时的搅拌和自由基清除剂的投加都降低了p-DCB的降解率,这是因为超声波降解时空化气泡内的热裂解和自由基作用的削弱.(5)在单一体系中,p-DCB比对氯苯胺(p-ClA)更易降解.在混合体系中,p-ClA的加入没有显著降低p-DCB的去除效果,因为亲水的p-ClA不易挥发,难以进入空化气泡竞争能量和自由基,其存在对空化气泡内混合气体的比热容比影响较小;而p-DCB的存在却明显降低了p-ClA的降解效果,因为疏水的p-DCB易挥发进入空化气泡竞争能量和自由基,并降低混合气体的比热容比.     

超声波降解四环素类抗生素废水

采用超声波降解模拟废水中四环素类抗生素(TCs):土霉素(OTC)、四环素(TC)和金霉素(CTC),考查废水初始浓度、初始pH、超声波输入功率密度、曝气量和自由基清除剂(正丁醇)对降解效率的影响。结果表明,超声波可以快速高效地降解废水中的TCs,CTC最易被降解,TC和OTC次之;在OTC、TC和CTC初始浓度0.25 mg/L,初始pH=8.2,声功率密度1.2 W/mL,气水体积比30∶1的条件下,超声波辐照20 min后去除率分别达到76.8%、84.0%和94.4%。在实验研究条件下,TCs去除率均随初始浓度(0.25~2.00 mg/L)的增大而降低,但总去除浓度升高;碱性条件有利于TCs降解,去除率随初始pH(6~11)升高而升高;功率密度(0.24~1.96 W/mL)越高,TCs去除率也越高;曝气后TCs的去除率明显升高,随着气水比(10∶1~60∶1)的增大,去除率逐渐上升;正丁醇有效抑制TCs超声波降解,可推断TCs主要降解途径为自由基氧化。TCs超声波降解过程符合伪一级动力学反应特征。     

超声波—光催化联合降解苯酚废水研究

超声降解和光催化降解均为自由基历程的高级氧化技术，同时，超声空化能够改善传质效果，因此，二者耦合能否产生协同效果是值得研究的，本文考察了苯酚溶液的超声降解、光降解、光催化降解、超声-光催化降解以及温度对光降解和光催化降解的影响，结果表明，40kHz,0.4W/cm^2的超声波对苯酚没有明显的降解作用，而对光催化降解只有轻微的促进作用。光降解和光催化降解的过程曲线显著不同，但温度对二者均有显著的促进作用。     

低频超声辐照降解间苯二酚水溶液的研究

利用低频超声波对模拟间苯二酚废水进行研究,主要讨论间苯二酚本身性质以及超声操作声强对降解的影响,并通过自由基清除剂实验判定该反应的反应类型.结果表明,间苯二酚本身性质以及超声声强对间苯二酚的超声降解影响都比较大,并且该超声降解反应过程以自由基氧化反应为主,同时该反应遵循表观一级动力学反应特征.初始浓度为200mg/L的间苯二酚反应液经强度0.4 W/cm2的超声波辐照4 h后,降解率为48.6%.     

低频超声辐照降解间苯二酚水溶液的研究

利用低频超声波对模拟间苯二酚废水进行研究，主要讨论间苯二酚本身性质以及超声操作声强对降解的影响，并通过自由基清除剂实验判定该反应的反应类型。结果表明，间苯二酚本身性质以及超声声强对间苯二酚的超声降解影响都比较大，并且该超声降解反应过程以自由基氧化反应为主，同时该反应遵循表观一级动力学反应特征。初始浓度为200mg／L的间苯二酚反应液经强度0．4W／cm^２的超声波辐照4h后，降解率为48．6％。     

利用紫外光降解多氯联苯(PCBs)的研究进展

本文综述了PCBs在各种溶剂中的紫外光化学反应特性和降解途径 :PCB的光化学反应以氢取代氯的脱氯反应为主 ,除此之外 ,在水或醇等极性溶液中 ,还存在羟基化反应 ;PCB的光化学反应活性与其氯原子的数量和取代位置有关。文章最后还简述了光降解在治理受PCB污染土壤方面的应用     

土壤中多氯联苯分析方法研究进展

文中综述了多氯联苯的分析技术及其研究进展。介绍了样品前处理技术如索氏萃取法、超声萃取法、微波辅助萃取、超临界流体萃取、加速溶剂萃取等在土壤样品中多氯联苯分析中的应用;阐述了气相色谱、液相色谱、气质联用技术在土壤样品中多氯联苯的检测,并对土壤中未来多氯联苯检测技术的发展提出了展望。     

Analysis of dioxin-like compounds in vegetation and soil samples burned in Catalan forest fires. Comparison with the corresponding unburned material

Only a few data are reported about the formation of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) in forest fires. However, the inventories of sources undertaken by several European and American countries consider natural fires as a possible source of PCDD/F and, in some cases, as one of the most important. In our work we have analysed vegetation and soil samples burned in four forest fires which happened in Catalonia in the summer of 1998. The concentration of dioxin-like compounds (PCDD/F, non-ortho polychlorinated bi-phenyls (PCB) and mono-ortho PCB) has been compared to the concentration present in the corresponding unburned material collected in places near the fires but not affected. The results of this preliminary study show very low concentrations in all the samples, both burned and unburned. Although a change in the profile (proportional increase of tetrachlorinated congeners in PCDD/F) is observed in burned samples compared to unburned ones, the absolute values of concentration decrease in most samples. Therefore, natural fires seem not to be an important source of dioxin-like compounds. These results will be confirmed with air emissions measurements in future studies.     

PCBs污染土壤的CaO诱导低温热处理脱氯研究

研究了低温热处理脱氯技术对废弃电容器封存点附近污染土壤中多氯联苯脱氯的效果,考察反应温度、反应时间及CaO添加比例对PCBs去除率、脱氯率的影响以及反应前后土壤中污染物的组分变化.实验土样中PCBs浓度为107.7 mg/g,属于罕见高浓度PCBs污染土壤.当反应温度为400℃、停留时间4h、CaO添加比例为10%,PCBs的去除率为87.7%,脱氯率为85.3%.土壤样品中五氯联苯和四氯联苯反应后含量降低或未检出,部分反应后样品检出一氯联苯和联苯,说明在CaO诱导PCBs低温热处理脱氯反应中存在逐步脱氯/加氢反应途径.     

Accumulation of hydroxylated polychlorinated biphenyls (OH-PCBs) and implications for PCBs metabolic capacities in three porpoise species

The present study investigated polychlorinated biphenyls (PCBs) and hydroxylated metabolites of PCBs (OH-PCBs) in blood from three porpoise species: finless porpoises (Neophocaena phocaenoides), harbor porpoises (Phocoena phocoena), and Dall’s porpoises (Phocoenoides dalli). The porpoises were found stranded or were bycaught along the Japanese coast. Concentrations of OH-PCB were the highest in Dall’s porpoises (58 pg g⁻¹ wet wt), second highest in finless porpoises (20 pg g⁻¹ wet wt), and lowest in harbor porpoises (8.3 pg g⁻¹ wet wt). The concentrations in Dall’s porpoises were significantly higher than the concentrations in finless porpoises and harbor porpoises (p < 0.05 and p < 0.01, respectively). There was a positive correlation between PCB and OH-PCB concentrations (r = 0.67, p < 0.001), suggesting the possible concentration-dependent induction of CYP enzymes. The three porpoise species may have exceptionally low metabolic capacities compared with other marine and terrestrial mammals, because low OH-PCB/PCB concentration ratios were found, which were 0.0016 for Dall’s porpoises, 0.0013 for harbor porpoises, and 0.00058 for finless porpoises. Distinct differences in the OH-PCB congener patterns were observed for the three species, even though they are taxonomically closely related.     

生物与化学表面活性剂协同洗脱土壤中PCBs的研究

通过序批实验和土柱淋洗实验研究了由生物表面活性剂鼠李糖脂(RL)与非离子化学表面活性剂十二烷基醇聚氧乙烯(6)醚(POE(6))混合得到的复配试剂洗脱污染土壤中多氯联苯(PCBs)的作用效果及其作用机理。结果表明,同一土样中,从批实验得到的PCBs洗脱率略高于土柱淋洗实验。RL与POE(6)两种单一试剂对人工污染土样中的PCBs洗脱率均大于60%,而对陈化土样中的洗脱率均不到20%,且土壤中的TOC含量越高,PCBs的洗脱率越低。在质量浓度为301 mg/L(10 CMC)及1 505 mg/L(50 CMC)的RL-POE(6)复配试剂中,RL与POE(6)对人工污染土壤中PCBs的洗脱具有一定的协同作用。当复配试剂的浓度为301 mg/L时,RL与POE(6)对陈化土样中PCBs的洗脱没有协同作用;但当RL-POE(6)的浓度增加到1 505 mg/L时,RL与POE(6)对陈化土样中PCBs的洗脱具有明显的协同作用。     

多氯联苯污染沉积物质量评价研究进展

介绍了多氯联苯污染沉积物质量评价的研究进展 ,其中 ,简单介绍了多氯联苯的有关概况及环境行为、沉积物质量评价方法及基准研究进展 ;最后 ,重点介绍了包括多氯联苯在内的憎水性有机物污染沉积物质量评价的研究现状及存在问题。     

Occurrence of pesticides and polychlorinated biphenyls in water of the Nile river at the estuaries of Rosetta and Damiatta branches,north of delta,Egypt

Abstract

A study was conducted from summer 1995 to summer 1997 to assess the seasonal occurrence of pesticide residues and other organic contaminants, polychlorinated biphenyls (PCBs), in water at the estuaries of Rosetta and Damiatta branches of the Nile river. The results indicated that organochlorine compounds (OCs) including HCB, lindane, p,p‘‐DDE, p,p‘DDD, p,p‘‐DDT, aroclor 1254 and aroclor 1260 were present in all the water samples at concentration levels ranging between 0.195–0.240, 0.286–0.352, 0.035–0.067, 0.019–0.033, 0.024–0.031, 0.390–0.70 and 0.166–0.330 μg/l, respectively. The levels of these compounds were higher in water of Damiatta branch than those found in water of Rosetta branch. Aldrin, dieldrin and endrin were not detected in all water samples. Only 4 compounds from 36 organophosphorus insecticides, fungicides and s‐triazine herbicides tested were detected in water samples collected during summer and autumn seasons from Rosetta branch. The concentration levels of these detected compounds, dimethoate, malathion, captan, and ametryne, ranged from 0.011 to 0.340 μg/l, respectively. Similar compounds during the same seasons as found in water of Rosetta branch were also detected in water of Damiatta branch except ametryne. The levels of the detected compounds (dimethoate, malathion and captan) ranged between 0.030 and 0.330 μg/l. The levels of detected organophosphorus insecticides, fungicides and s‐triazine herbicides were in the order: dimethoate > malathion > captan > ametryne.