微气泡曝气 O3/ H2O2处理 RO 浓水的效能及影响因素简

采用O₃/H₂O₂高级氧化工艺处理炼油厂反渗透（RO）浓水，用溶气泵加压溶气并产生微气泡强化传质，确定装置运行条件，考察气体中臭氧浓度、H₂O₂/O₃初始摩尔比、pH和温度对O₃/H₂O₂处理RO浓水效果的影响，并对RO浓水处理效能进行研究。结果表明，随着气体中臭氧浓度的增加，COD的去除率基本呈线性增加；加入适当量H₂O₂能提高臭氧氧化RO浓水的效果，H₂O₂/O₃初始摩尔比在0~0.8范围内，COD的去除率先增加后下降，H₂O₂/O₃初始摩尔比为0.5时COD去除率最大；pH从6.84增加到9.01，COD去除率逐渐增大，pH为10.03时COD去除率反而降低；在14~28℃范围内，温度低时，升高温度COD去除率增加较大，温度较高时，升高温度对COD去除率的影响较小。为考察该工艺的稳定性，在H₂O₂/O₃初始摩尔比为0.5、溶液pH为8~9、臭氧浓度为80~100 mg/L、温度为10~28℃条件下，对COD为90~140 mg/L的RO浓水氧化处理4~10 h，出水COD维持在39.9~49.9 mg/L，达到《城镇污水处理厂污染物排放标准（GB 18918-2002）》中的一级A标准；去除1 g COD消耗O₃ 1.4~3.3 g，消耗O₃与H₂O₂的总氧量为2.2~4.4 g。     

氨吹脱-Fenton氧化预处理阿奇霉素废水的研究

采用氨吹脱-Fenton试剂氧化法对阿奇霉素废水进行预处理，考察了各种因素对处理效果的影响。实验结果表明：在pH值为11，吹脱时间160 min，温度30℃的条件下，氨氮浓度从2 458.7 mg/L降低到421.7 mg/L，去除率可达82.85%；Fenton氧化吹脱出水的适宜工艺条件：初始pH值为3、反应时间90 min、FeSO₄·7H₂O投加量为0.01 mol/L、H₂O₂/Fe²⁺的投加比16∶1，此时，COD去除率为72.6%；废水经预处理后，有效地改善了废水水质，提高了废水的可生化性，由初始的0.1增至0.37，为后续废水的生化处理提供了有利条件。     

UV-Fenton光催化氧化处理高浓度邻苯二甲酸二辛酯生产废水

采用UV-Fenton技术光催化氧化高浓度邻苯二甲酸二辛酯（DOP）生产废水，确定最佳操作条件为：初始pH=3.8，H₂O₂浓度为9.99 g/L，H₂O₂/Fe²⁺摩尔比为20∶1，光照反应60 min。此条件下的废水COD去除率为89.1%，出水COD值在570 mg/L左右。经正交试验确定影响处理效果各因素的重要性顺序为：H₂O₂浓度＞H₂O₂/Fe²⁺摩尔比＞光照反应时间＞pH。UV的加入与单独的Fenton体系存在正相关的协同作用。废水降解的表观过程符合一级反应动力学模式。     

O3/UV预处理磺酰脲类除草剂生产废水的研究

采用O₃/UV工艺预处理磺酰脲类除草剂生产废水，考察了初始pH值、臭氧投量、叔丁醇投加等因素对废水处理效果的影响，并初步探讨了该工艺处理废水的反应机理。实验结果表明，在废水初始pH为13.59和臭氧投量为65.08 mg/min的条件下，预处理80 min后废水COD去除率达63.47%，BOD₅/COD由0.03提高至0.56，EC50从11%提高至55%。随着叔丁醇浓度的增加，废水COD去除率明显降低，证明该反应体系有?OH存在；体系中加入MnO₂后废水COD去除率下降了16%，氧化效率明显下降，证明该反应体系内中间产物H₂O₂在O₃/UV降解有机废水过程中起到了重要的作用。     

O3、H2O2/O3及UV/O3在焦化废水深度处理中的应用

采用O₃、H₂O₂/O₃和UV/O₃等高级氧化技术(AOPs)对某焦化公司的生化出水进行深度处理，考察了O₃与废水的接触时间、溶液pH、反应温度等因素对废水COD去除率的影响，确定出O₃氧化反应的最佳工艺参数为：接触时间40 min，溶液pH 8.5，反应温度25℃，此条件下废水COD及UV₂₅₄的去除率最高可达47.14%和73.47%；H₂O₂/O₃及UV/O₃两种组合工艺对焦化废水COD及UV₂₅₄的去除率均有一定程度的提高，但H₂O₂/O₃系统的运行效果取决于H₂O₂的投加量。研究结论表明，单纯采用COD作为评价指标，并不能准确反映出O₃系列AOPs对焦化废水中有机污染物的降解作用。     

天然沸石负载La2O3-ZnO-TiO2光催化降解活性艳红K-2BP

利用80目天然斜发沸石作载体制备La₂O₃(0.5%)-ZnO(20%)-TiO₂/沸石复合光催化剂，以20 W紫外灯为光源，在自制的光催化反应器中降解活性艳红K-2BP，考察了光照时间、空气通入量、催化剂用量、溶液初始浓度、H₂O₂与Fe³⁺投加量等对活性艳红K-2BP光催化降解率的影响。结果表明，当溶液初始浓度为60 mg/L，催化剂投加量为12 g/L，通气量为1 200 mL/min，光照2.5 h，活性艳红K-2BP的降解率可达99.2%；H₂O₂和Fe³⁺投加量为4 mL/L和3 g/L时，光照1 h活性艳红K-2BP降解率分别为100%和97.2%。紫外可见吸收光谱显示，LZTZ光催化剂可有效降解印染废水。     

O3/H2O2降解阿特拉津影响因素研究

采用O3/H2O2氧化去除水中内分泌干扰物阿特拉津，考察了反应条件及水质对去除的影响，并对反应机制进行了初步探讨。阿特拉津初始浓度2 mg/L，投量为7.5 mg/L的O₃单独氧化去除率为27.2%；相同O₃投量下，控制H₂O₂/O₃摩尔比为0.75，5 min阿特拉津的去除率最高可达96.5%；pH 值为7.5～8.5，温度在25～40℃的范围内，都维持了较高的去除率，表明H₂O₂/O₃体系对阿特拉津的去除效果良好，降解速度快，反应条件温和。0.5 mg/L的腐殖酸，对阿特拉津的去除影响不大，腐殖酸浓度为1、2和5 mg/L时，平均去除率分别为63.4%、50.7%和30.2%；碳酸氢钠的浓度为50和200 mg/L时，去除率分别为88.1%和73.8%，说明水质对阿特拉津的去除影响较大。叔丁醇的浓度为5和20 mg/L时，阿特拉津的去除率分别降低到44.7%和27.5%，去除率随自由基抑制剂叔丁醇增加而降低，说明H₂O₂/O₃降解阿特拉津主要为该体系产生的羟基自由基的贡献。     

vis／H2O2／草酸铁处理活性艳红染料的实验研究

采用vis／H₂O₂／草酸铁法，对活性艳红染料废水进行处理。研究了H₂O₂、K₂C₂O₄和Fe₂(SO₄)₃·7H₂O的投加量、pH值和光照时间等因素对染料废水处理效果的影响和最佳处理条件。结果表明，pH值2.5；30%H₂O₂的投加量0.1 mL；0.1 mol/L Fe₂(SO₄)₃·7H₂O的投加量1.0 mL；0.1 mol/L K₂C₂O₄的投加量1.5 mL；光照时间40 min的最佳条件下，70 mg/L的活性艳红模拟染料废水脱色率可达99.82%。通过对vis／H₂O₂／草酸铁法和Fenton法、H₂O₂法、草酸铁法等方法进行对比实验，vis／H₂O₂／草酸铁法明显优于其他方法，是一项有研究价值和开发应用前景的污染治理新技术。     

用H2O2/Fe3+处理高浓度含甲醛废水的研究

研究采用H₂O₂/Fe³⁺催化氧化处理高浓度含甲醛废水，探讨了双氧水和催化剂投加量、反应pH及反应温度等操作条件对处理效果的影响，并通过酸溶解回用失活催化剂。结果表明，较优的操作条件为：H₂O₂/COD（质量比）=2.2～2.6，Fe³⁺/H₂O₂（摩尔比）=0.048～0.058，反应pH 1.80～2.68，反应温度50℃，反应时间40 min；在上述操作条件下，甲醛去除率达到99%以上，COD去除率达到85%以上。失活的催化剂可通过稀酸溶解后循环使用，其效果与三价铁盐作催化剂的基本相同。采用H₂O₂/Fe³⁺处理含甲醛废水具有比采用H₂O₂/Fe³⁺较优的效果。     

微波促进含Cr(VI)-H2O2体系降解甲基橙溶液的研究

研究了微波辐射下Cr(VI)－H₂O₂催化降解甲基橙溶液的行为，探索了微波功率、微波辐射时间、pH值、H₂O₂浓度、Cr(VI)等对甲基橙溶液脱色率和COD去除率的影响。研究结果表明，Cr(VI)-H₂O₂能形成类Fenton体系；微波辐射可提高H₂O₂产生羟基自由基(·OH)的效率。1000 mg/L的甲基橙溶液，在Cr(VI)浓度为10.0 mmol/L、pH值为2.5、H₂O₂浓度为20.0 mmol/L、微波功率为700W下加热2 min，甲基橙溶液的脱色率为99.2%，COD去除率为82.8%。     

Evaluation of trichloroethene recovery processes in heterogeneous aquifer cells flushed with biodegradable surfactants

The ability of two biodegradable surfactants, polyoxyethylene (20) sorbitan monooleate (Tween 80) and sodium dihexyl sulfosuccinate (Aerosol MA), to recover a representative dense non-aqueous-phase liquid (DNAPL), trichloroethene (TCE), from heterogeneous porous media was evaluated through a combination of batch and aquifer cell experiments. An aqueous solution containing 3.3% Aerosol MA, 8% 2-propanol and 6 g/l CaCl(2) yielded a weight solubilization ratio (WSR) of 1.21 g TCE/g surfactant, with a corresponding liquid-liquid interfacial tension (IFT) of 0.19 dyn/cm. Flushing of aquifer cells containing a TCE-DNAPL source zone with approximately two pore volumes of the AMA formulation resulted in substantial (>30%) mobilization of TCE-DNAPL. However, a TCE mass recovery of 81% was achieved when the aqueous-phase flow rate was sufficient to displace the mobile TCE-DNAPL toward the effluent well. Aqueous solutions of Tween 80 exhibited a greater capacity to solubilize TCE (WSR=1.74 g TCE/g surfactant) and exerted markedly less reduction in IFT (10.4 dyn/cm). These data contradict an accepted empirical correlation used to estimate IFT values from solubilization capacity, and indicate a unique capacity of T80 to form concentrated TCE emulsions. Flushing of aquifer cells with less than 2.5 pore volumes of a 4% T80 solution achieved TCE mass recoveries ranging from 66 to 85%, with only slight TCE-DNAPL mobilization (<5%) occurring when the total trapping number exceeded 2 x 10(-5). These findings demonstrate the ability of Tween 80 and Aerosol MA solutions to efficiently recover TCE from a heterogeneous DNAPL source zone, and the utility of the total trapping number as a design parameter for a priori prediction of DNAPL mobilization and bank angle formation when flushing with low-IFT solutions. Given their potential to stimulate microbial reductive dechlorination at low concentrations, these surfactants are well-suited for remedial action plans that couple aggressive mass removal followed by enhanced bioremediation to treat chlorinated solvent source zones.     

Chloroaromatic pollutants in mussels incubated in two finnish watercourses polluted by industry

Concentrations of different chlorinated compounds were measured in mussels incubated in two polluted watercourses, a river (the River Kymijoki) and a lake (Lake Vanaja) for four weeks in summer 1995. The sum concentrations of polychlorinated phenols (PCP) and biphenyls (PCB) were both about 1 μg/g lipid weight (lw) in Lake Vanaja mussels, while in the River Kymijoki mussels PCPs were non-detectable and PCBs were measured 120 ng/g lIw. The concentrations of toxic polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners ranged between <17 and 370 pg/g Iw in Lake Vanaja mussels and between <38 and 11,000 pg/g lw in the River Kymijoki mussels. Polychlorinated diphenyl ethers (PCDE) were detected in the mussels incubated in the River Kymijoki (0.4–1.1 ng/g Iw), but not in those incubated in Lake Vanaja. Polychlorinated phenoxyanisoles (PCPA) were measured 33 ng/g lw and polychlorinated phenoxyphenols (PCPP) 300 ng/g lw in the mussels incubated in the River Kymijoki. PCPAs were also detected in reference samples, which were sediment and pike from the River Kymijoki and Baltic salmon, seal and white-tailed sea eagle.     

The variation of street air levels of PAH and other mutagenic PAC in relation to regulations of traffic emissions and the impact of atmospheric processes

The occurrence of particle associated PAH and other mutagenic PAC was determined in 1996 in the street air of Copenhagen. In addition, particle extracts were tested for mutagenicity. The measurements were compared with previous measurements in 1992/1993. The levels had decreased in this period. The decrease was caused by an implementation of light diesel fuels for buses and the exchange of older petrol-driven passenger cars with catalystequipped new ones. About 65% of the reduction was caused by the application of the light diesel fuels. Under special conditions, chemical processes in the atmosphere produced many more mutagens than the direct emissions. The concentrations of S-PAC and N-PAC were 10 times lower than those of PAH, while the levels of oxy-PAH were in the same order of magnitude as those of PAH. Benzanthrone, an oxy-PAH, is proposed to be formed in the atmosphere in addition to direct emissions. Benzo(a)pyrene, often applied as an air quality criteria indicator, was photochemically degraded in the atmosphere. A strong increase in the mutagenic activities was observed to coincide with a depletion of benzo(a)pyrene.     

Teratological effects of pesticides in vertebrates: a review

Abstract

In the last decades, the use and misuse of pesticides in the agriculture have increased, having a severe impact on ecosystems and their fauna. Although the various effects of pesticides on biodiversity have been already documented in several studies, to our knowledge no consistent overview of the impact of pesticides in vertebrates, both terrestrial and aquatic, is available. In this review, we try to present a concise compilation of the teratogenic effects of pesticides on the different classes of vertebrates – mammals, birds, reptiles, amphibians and fish.     

Book review

The Pesticide Manual ‐ A World Compendium, 8th Edition, C.R. Worthing, Editor and S.B. Walker, Assistant Editor, British Crop Protection Council, BCPC Publications Sales, Bear Farm, Binfield, Bracknell, Berkshire RG12 5QE, England. 1987, 1100 pp., UK £50; Overseas £56. ISBN 0–948404–01–9.     

Patterns of volatile metabolites and nonvolatile trichothecenes produced by isolates of <Emphasis Type="Italic">Stachybotrys,Fusarium, Trichoderma,Trichothecium</Emphasis> and <Emphasis Type="Italic">Memnoniella</Emphasis>

We reported previously that trichodiene, a volatile trichothecene derivative, was produced by a Stachybotrys isolate, also known to produce highly cytotoxic, non-volatile, macrocyclic trichothecenes (satrotoxins). We investigated the relationship between the production of trichodiene and various non-volatile trichothecenes for several molds. Volatile metabolites were concentrated by adsorption on Tenax TA and analyzed by GC/MS, while non-volatile metabolites were separated by HPLC, derivatized and analyzed by GC/MS. Stachybotrys chartarum isolates producing macrocyclic trichothecenes secreted significantly larger amounts of trichodiene and other sesquiterpenes than isolates which only produced simple trichothecenes. The amounts of secreted trichodiene were relatively small in all cases. With the exception of Memnoniella, which excreted small amounts of sesquiterpenes, the other isolates produced varying amounts of sesquiterpenes, including trichodiene, as well as simple tricothecenes, no detectable trichodiene, but large amounts of griseofulvin derivatives. In Stachybotrys there is apparently a correlation between trichodiene and macrocyclic trichothecene production. In the remaining isolates, there was no simple relationship between trichodiene and non-volatile trichothecene synthesis. Trichodiene is produced in larger amounts by Stachybotrys isolates, which also produce satratoxins, but it will be difficult to utilize this metabolite to detect toxic isolates in buildings due to the relatively small amounts excreted.     

Observations on the influence of water and soil pH on the persistence of insecticides

Abstract

The pH‐disappearance rate profiles were determined at ca. 25°C for 24 insecticides at 4 or 5 pH values over the range 4.5 to 8.0 in sterile phosphate buffers prepared in water‐ethanol (99: 1 v/v). Half‐lives measured at pH 8 were generally smaller than at lower pH values. Changes in half lives between pH 8.0 and 4.5 were largest (>1000x) for the aryl carbamates, carbofuran and carbaryl, the oxime carbamate, oxamyl, and the organophosphorus insecticide, trichlorfon. In contrast, half lives of phorate, terbufos, heptachlor, fensulfothion and aldicarb were affected only slightly by pH changes. Under the experimental conditions described half lives at pH8 varied from 1–2 days for trichlorfon and oxamyl to >1 year for fensulfothion and cyper‐methrin. Insecticide persistence on alumina (acid, neutral and basic), mineral soils amended with aluminum sulfate or calcium hydroxide to different pH values and four natural soils of different pH was examined. No correlation was observed between the measured pH of these solids and the rate of disappearance of selected insecticides applied to them. These observations demonstrate the difficulty of extrapolating the pH dependent disappearance behaviour observed in homogeneous solution to partially solid heterogeneous systems such as soil.     

The chemical stability of formulations of some hydrolyzable insecticides in aqueous mixtures with hydrolysis catalysts

Abstract

The active ingredients in commercial formulations of malathion, oxamyl, carbaryl, diazinon, and chlorpyrifos diluted to “spray tank”; concentrations with buffered distilled or natural water of pH 4–9 were stable for at least 24 hr. Formulations of trichlorfon were not stable at pH 7 or above but disappearance rates were slower than for the pure chemical in homogeneous solution. Cupric ion was observed to be an effective catalyst for the hydrolysis of a variety of pure organophosphorus insecticides but did not catalyze hydrolysis of the active ingredients of the formulations examined. Increasing the dilution of the formulation increased the susceptibility of malathion, oxamyl, and carbaryl to hydrolysis.     

Organochlorine compounds in a three-step terrestrial food chain

The concentrations of 15 organochlorine chemicals (PCBs and pesticides) were studied in a Central European oak wood food chain system: Great tit (Parus major), caterpillars (Tortrix viridana, Operophtera brumata, Erannis defoliaria), and oak-leaves (Quercus robur). Juvenile tits receive organochlorines from the mother via egg transfer and, eventually to a greater extent, from the caterpillar food source during nestling period. The concentrations of PCB 153 (2,2′,4,4′,5,5′-hexachlorobiphenyl, the most abundant in this study) was found in leaf material at ca. 1 ng/g, in caterpillars 10 ng/g, and in bird eggs 170 ng/g on an average and on a dry mass basis.     

Knowledge transfer initiative between molecular biologists and environmental researchers and regulators

A Natural Environment Research Council (NERC) funded Knowledge Transfer (KT) workshop was held in the United Kingdom (UK) to identify the needs and opportunities in the application of molecular biology and ‘omics’ techniques to environmental monitoring and risk assessment. Attendees highlighted a lack of effective communication between end-users and researchers as well as difficulties with data interpretation as reasons behind the slow uptake of molecular biology and omics techniques. A number of promising areas in which new techniques could be implemented at a practical level in the very near future were identified, thereby raising the profile of these recent technologies and providing vital proof of concept work. Molecular taxonomy, bacterial source tracking and pre-screening of chemicals for potential toxicities were all viewed as areas in which omics and molecular techniques could have immediate value, with the aim of reducing cost, increasing efficiency and providing more comprehensive data of improved quality.