利用烧结处理废旧电池的工艺研究

对利用烧结处理废旧电池的工艺进行了试验研究.结果表明,在焙烧温度为400℃、时间为90 min时,汞的去除率可达99%以上;在焙烧温度为1100℃、时间为90 min时,脱锌率可达到95%;将除汞除锌后的电池样添加到烧结原料中,其量为1%时,对烧结矿质量基本没有影响,说明该技术处理废旧电池是可行的,可为我国废旧电池的处理和利用开辟一条新的途径.     

废锌锰电池真空蒸馏法去除汞的研究

废锌锰电池回收利用中的正交实验,研究蒸馏温度、系统压强和蒸馏时间对去除汞的综合影响;寻找去除汞的最优工艺条件.根据实验结果,使用真空蒸馏的方法处理锌锰电池优化的工艺参数为:蒸馏温度500～600℃,蒸馏时间60～80 min,系统压强3000～7000 Pa.     

回转窑热解处理废锌锰电池试验研究

利用回转窑装置热解处理废锌锰电池,考察了热解温度、热解时间和载气流速对热解脱汞效果的影响,研究了汞被吸收的规律、尾气的成分以及废锌锰电池的物质形态变化.研究结果表明:在热解温度为690 ℃,热解时间为100min,载气流速为0.06 m3/h的条件下脱汞效果最好.热解时间对脱汞效果影响最大,热解温度次之,载气流速的影响很小.吸收液能完全吸收通过吸收瓶的尾气中含有的汞,其中95%以上的汞以单质形式存在.热解残渣中晶态物质多,金属元素呈低价态.     

废汞触媒中汞的浸出及其再生活性炭的吸附性能

对电石法生产聚氯乙烯产生的废汞触媒进行浸出及再生活性炭的研究,以6 mol·L~(-1)HCl溶液作为浸出剂,在浸出反应温度为65℃、浸出反应时间为90 min和液固比为15∶1的实验条件下得到Hg~(2+)的优化浸出率为61.25%。采用扫描电镜(SEM)、Brunauer-Emmet-Tller(BET)比表面积等方法分析再生活性炭特征。结果表明焙烧废汞触媒浸出渣热再生活性炭是可行的,焙烧最佳工艺条件为:焙烧温度850℃,焙烧时间90 min。得到的焙烧产物亚甲基蓝吸附值为120.5 mg·g~(-1),BET表面积为704.25 m~2·g~(-1),平均孔径为3.28 nm。再生前后的汞含量与从1.067%降至0.351%,再生后能再次作为汞触媒生产的催化剂载体材料,同时减缓固废堆积过程中汞流失造成的一系列环境问题。     

中温焙烧/钠化氧化法回收电镀污泥中的铬

采用中温焙烧/钠化氧化法从电镀污泥中回收铬.结果表明,影响铬浸出率的最主要因素为焙烧温度.电镀污泥与碳酸钠质量比、焙烧时间、水浸时间对铬浸出率的影响较接近,在水浸水固比为10.0 ; 1.0(质量比)、室温、焙烧温度为650℃、焙烧时间为2.0h、电镀污泥与碳酸钠质量比为1:1、水浸时间为60 min的最佳浸出条件下,铬浸出率为99.3%;去除氢氧化铝、氢氧化锌的最佳反应温度和pH分别为90～95℃和7.5;去除硫酸钠晶体的最佳pH为4.0,在最佳试验条件下,铬回收率为90.57%.     

废锌锰电池真空蒸馏法去除汞的研究

废锌锰电池回收利用中的一个关键问题是实现汞的无害化。介绍了使用真空蒸馏装置，通过单因素实验和正交实验，研究蒸馏温度、系统压强和蒸馏时间对去除汞的综合影响；寻找去除汞的最优工艺条件。根据实验结果，使用真空蒸馏的方法处理锌锰电池优化的工艺参数为：蒸馏温度500～600℃，蒸馏时间60～80min，系统压强3000～7000Pa。     

用于水处理的高效除磷型粉煤灰陶粒滤料的研制

为制备用于处理含磷废水的新型功能陶粒滤料,研究了以粉煤灰为主要原料的高效除磷型陶粒烧结制备工艺。通过L9（34）正交实验和极差分析,结合筒压强度实验得到最佳烧结条件为：预热时间30 min,烧结温度950℃,烧结时间30 min;各因子对除磷效率的影响程度为：烧结温度〉烧结时间〉预热时间。通过理化性质测试得出最佳工艺制备的陶粒特性：堆积密度为877 kg/m3,表观密度为1 509 kg/m3,空隙率为41.9%,筒压强度6.94 MPa,盐酸可溶率为2.3%。应用最佳工艺条件所制备的陶粒处理10 mg/L含磷废水获得高达99.83%的磷酸盐去除率。通过最佳烧结工艺能够制备高效除磷型粉煤灰陶粒滤料,在处理含磷废水方面具有一定的应用前景。     

半干法烧结烟气脱硫灰的氧化改性

半干法烧结烟气脱硫灰中含有大量CaSO_3,而CaSO_3对于脱硫灰的稳定性具有重要影响,限制了脱硫灰的处理和综合利用。为了解决该问题,采用低温静态氧化改性实验和高温动态焙烧改性实验,在掺加和不掺加催化剂条件下,对含CaSO_3的脱硫灰进行了氧化改性研究,并结合热重实验考察了半干法烧结烟气脱硫灰中CaSO_3的高温动态氧化改性效果。结果表明,在低温为45、75和90℃时,掺入不同催化剂对半干法烧结烟气脱硫灰中CaSO_3进行氧化改性2 h,效果依次为:MnO_2Fe_2O_3不掺催化剂V_2O_5,且CaSO_3的氧化率均低于2.2%;在不掺催化剂的条件下,在350℃以上焙烧30~60 min,CaSO_3的氧化率均可达到85%以上。结合热重分析结果发现,选择合适的焙烧温度和时间对提高CaSO_3的氧化率有重要作用。     

含砷冶炼废渣高温烧结过程砷的迁移特性

研究了烧结温度和烧结时间对含砷冶炼废渣烧结过程中砷的迁移特性的影响。烧结条件为在10 MPa下加压成型,进空气流量为2 000 mL/min,烧结温度1 000～1 350℃,烧结时间5～120 min。结果表明,烧结过程中存在砷的挥发,但烧结前后砷的总量变化不大,砷的固化率均保持在90%以上。毒性浸出实验表明,不同的烧结条件对烧结体中砷的毒性浸出有重要的影响,从烧结体的环境安全性考虑,最佳的烧结温度和时间分别为1 200℃和45 min。     

河道底泥陶粒烧制的工艺条件及性能研究

探讨以河道底泥、污水污泥、黏土为原料制作陶粒的最佳烧制工艺条件,利用单因素实验对陶粒性能进行比较分析,利用X射线衍射(XRD)、扫描电子显微镜(SEM)对微观结构进行表征分析。结果表明:以河道底泥烧制陶粒是可行的,预热温度和时间的控制将影响陶粒的轻质化,烧结温度应接近陶粒低共熔点,通过改变烧结时间可获得不同类型陶粒。烧制高强陶粒时,在陶粒体系低共熔点温度环境下延长烧结时间比单纯提高烧结温度更恰当。以预热温度400℃、预热时间20min、烧结温度1 175℃、烧结时间25min为烧制条件制作的河道底泥陶粒具有良好的性能,堆积密度为620kg/m~3,表观密度为1 125kg/m~3,筒压强度约为0.7MPa,吸水率达36.27%。     

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.     

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.     

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.     

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.     

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.     

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.