气液混合脉冲放电等离子体再生活性炭系统优化研究

为了丰富活性炭再生方法,并拓宽脉冲放电等离子体技术的应用范围,研究建立了气液混合的脉冲放电等离子体体系,将其用于吸附酸性橙II(AO7)饱和活性炭的再生。通过实验,考察了气液混合方式、脉冲电压、脉冲频率和电极间距等关键参数对活性炭再生效果的影响规律,进而对该再生体系进行优化。研究结果表明,气液分离式的气液混合方式较利于该脉冲放电等离子体体系中活性炭的优化;在一定范围内提高脉冲电压,可以提高其中活性炭的再生效果;高的脉冲频率下活性炭再生效果好;气液混合脉冲放电等离子体体系中适宜于活性炭再生的电极间距为20mm。     

高频脉冲介质阻挡放电去除水中17β-雌二醇

实验采用高频脉冲介质阻挡放电工艺处理水体中的17β-雌二醇（E2）。结果表明,该工艺可以有效地降解水中的E2,E2的降解过程符合一级反应动力学模型。当体系脉冲峰-峰电压为24kV,初始浓度为100μg／L的E2在超纯水中的降解一级反应速率常数为0．1314min^-1。E2的降解速率常数随脉冲峰-峰电压的增大而升高,随E2初始浓度和溶液初始pH增加而降低,溶液初始电导率对E2的降解影响不大。     

介质阻挡放电氧化降解木质素磺酸钠的动力学研究

为了有效地处理难生物降解的造纸废水,采用气相介质阻挡放电产生氧化性物质,对木质素磺酸钠进行了氧化降解研究。在不同操作条件下,对其降解动力学及矿化程度进行了研究。结果表明,介质阻挡放电能有效地降解木质素磺酸钠,其氧化降解反应遵循准一级动力学反应。当峰值电压为20 kV,被水蒸气饱和的空气为气源,流量为7 L/min时,氧化处理60 min后,木质素磺酸钠降解率达到70％。其速率常数K随峰值电压、气源、气体流量和木质素磺酸钠的初始浓度的变化而不同。气体流量越大,木质素磺酸钠的初始浓度越低,速率常数K越大,降解效果越好。随着处理时间的增加,氧化性物质能将部分木质素磺酸钠矿化使溶液TOC降低,当被水蒸气饱和的空气作为气源时,氧化处理120min,21.38%的TOC被去除。     

亚铁催化声化学降解罗丹明B

比较了不同金属离子对罗丹明B的声化学降解作用,发现超声时加入Fe2 反应速率常数为单独超声波降解时的1.6倍,反应在前5 h内符合假一级动力学.研究了亚铁离子强化声化学对罗丹明B的降解作用,考察了Fe2 用量,溶液初始pH值,曝气,反应温度和超声功率等因素对脱色速率的影响.研究表明,酸性条件有利于染料的脱色;有曝气时的声化学脱色速率常数是单独超声时的6倍;声化学反应的活化能较低,反应在低温就可以进行;超声功率的改变对脱色速率的影响不大.UV-VIS扫描图谱显示,染料在225 nm和256 nm处的紫外吸收明显降低,初步探讨了罗丹明B的降解机理.     

亚铁催化声化学降解罗丹明B

比较了不同金属离子对罗丹明B的声化学降解作用，发现超声时加入Fe^2＋反应速率常数为单独超声波降解时的1．6倍，反应在前5h内符合假一级动力学。研究了亚铁离子强化声化学对罗丹明B的降解作用，考察了Fe^2＋用量，溶液初始pH值，曝气，反应温度和超声功率等因素对脱色速率的影响。研究表明，酸性条件有利于染料的脱色；有曝气时的声化学脱色速率常数是单独超声时的6倍；声化学反应的活化能较低，反应在低温就可以进行；超声功率的改变对脱色速率的影响不大。UV-VIS扫描图谱显示，染料在225nm和256nm处的紫外吸收明显降低，初步探讨了罗丹明B的降解机理。     

染料结晶紫降解菌分离及其特性研究

从印染废水中筛选分离得到结晶紫（CV）降解菌株H，并对其脱色条件和机理进行了研究。结果表明，在外加生长基质条件下，菌株H不仅对CV降解脱色而且能降解中间产物。在pH7．0、35℃、摇床转速180r／min条件下，菌株H有最佳的脱色效果。对于20mg／L CV溶液，生长细胞降解0．5h，脱色率可达95％。休眠细胞对CV的降解规律也进行了对比探讨。菌株H对CV脱色过程遵循一级动力学方程，脱色速率常数k随CV浓度升高而降低，生长细胞的k值约为休眠细胞的6～7倍。     

亚甲基蓝溶液的光催化脱色及降解

以高压汞灯为光源,在自ＴｉＯ２纳米粉末悬浮体系内,以在蓝溶液光催化降解脱色反应为模型,研究了其脱色降解动力学及其影响因素。研究表明,亚甲基蓝光催化反应动力学常数为４．５３μｍｏｌ／Ｌ．ｍｉｎ．吸附常数为３３．５５Ｌ／ｍｍｏｌ;随着ｐＨ值的上升以及Ｈ２Ｏ２的加入,其脱色降解速率加快。     

高压电弧放电处理偶氮染料废水

用高压电弧放电产生的低温等离子体对含偶氮染料的废水进行了处理,以甲基橙为例研究了电压幅值、处理时间、溶液初始浓度、溶液初始pH值、投加Fe^2＋和Fe^3＋对染料脱色的影响。实验结果表明,甲基橙浓度为50mg／L时其降解率随时间和电压幅值的增加而增加。溶液初始浓度对染料去除效果影响较为明显,同等条件下初始浓度越低降解率越高。酸性条件下有利于低温等离子体处理甲基橙。Fe^2＋和Fe^3＋对低温等离子体降解甲基橙有一定的催化作用。电压8kV处理3min,Fe^2＋为20mg／L时去除率由89．64％增至99．72％。Fe2（SO4）,的最佳投加量为5mg／L（以Fe^3＋计）,而FeCl,的最佳投加量为80mg／L（以Fe^3＋计）。     

偶氮染料脱色菌Lysinibacillus sp.FS1的脱色性能

从佛山某工业园印染废水处理厂曝气池中,经梯度驯化筛选出一株对多种染料具有较强脱色能力的菌株FS1,通过16S r DNA基因序列分析初步鉴定为Lysinibacillus sp.,研究了该菌株在不同营养条件(氮源、碳源、碳源浓度),不同培养条件(p H、温度、供氧条件),不同染料(甲基橙、亚甲基蓝、中性红、酸性红B)和染料浓度下的脱色性能。结果表明,该菌株的最佳脱色条件:温度30~40℃,p H 7~9,氯化铵1 g/L,葡萄糖2 g/L的厌氧条件下培养脱色效果最好,10 h时对酸性红B脱色率可达98.73%左右,且脱色过程符合一级反应动力学方程:-ln(At/A0)=0.0588t-0.0448。该菌株可降解多种染料,脱色率均随污染强度的升高先增大后减小,对高浓度染料和混合染料也表现出很好的脱色效果,是一株高效广谱的染料降解菌,具有处理印染废水的开发应用价值。     

辉光放电电解等离子体降解水中阳离子红XL-GRL

针对染料废水色度高、难生物降解等问题,提出了用辉光放电电解等离子体(GDEP)技术降解染料废水阳离子红XL-GRL的方法。研究了放电电压、溶液浓度对脱色率的影响;测定了GDEP产生的活性物质以及降解过程中溶液的电导率、pH和TOC去除率的变化;分析了降解中间产物成分。结果表明,在600 V电压下,GDEP产生了HO?、H?、O?等高活性物质,他们可使染料分子在130 min内的脱色率达到93.32%,在120 min内TOC去除率达到了65.80%。降解过程中产生了大量带电离子及酸性中间产物。推测可能的降解机理是,阳离子红XL-GRL分子在HO·作用下双键断裂,生成酚类等产物,接着继续降解为中间产物醌,并进一步氧化为小分子有机酸,最终矿化为CO_2、H_2O和简单的无机离子。GDEP在有机染料废水处理方面具有一定的应用前景。     

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.     

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.     

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.     

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.     

Radionuclides in pinon pine (Pinus edulis) nuts from los alamos national laboratory lands and the dose from consumption

Abstract

One of the dominant tree species growing within and around the eastern portion of Los Alamos National Laboratory (LANL), Los Alamos, NM, lands is the pinon pine (Pinus edulis). Pinon pine is used for firewood, fence posts, and building materials and is a source of nuts for food—the seeds are consumed by a wide variety of animals and are also gathered by people in the area and eaten raw or roasted. This study investigated the (1) concentration of ³H, ¹³⁷Cs, ⁹⁰Sr, ^totU, ²³⁸Pu, ^{239, 240}Pu, and²⁴¹ Am in soils (0‐ to 12‐in. [31 cm] depth underneath the tree), pinon pine shoots (PPS), and pinon pine nuts (PPN) collected from LANL lands and regional background (BG) locations, (2) committed effective dose equivalent (CEDE) from the ingestion of nuts, and (3) soil to PPS to PPN concentration ratios (CRs). Most radionuclides, with the exception of ³H in soils, were not significantly higher (p < 0.10) in soils, PPS, and PPN collected from LANL as compared to BG locations, and concentrations of most radionuclides in PPN from LANL have decreased over time. The maximum net CEDE (the CEDE plus two sigma minus BG) at the most conservative ingestion rate (10 lb [4.5 kg]) was 0.0018 mrem (0.018 μSv); this is far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem (1000 μSv). Soil‐to‐nut CRs for most radionuclides were within the range of default values in the literature for common fruits and vegetables.     

Degradation and sorption of imidacloprid in dissimilar surface and subsurface soils

Degradation and sorption/desorption are important processes affecting the leaching of pesticides through soil. This research characterized the degradation and sorption of imidacloprid (1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine) in Drummer (silty clay loam) and Exeter (sandy loam) surface soils and their corresponding subsurface soils using sequential extraction methods over 400 days. By the end of the incubation, approximately 55% of imidacloprid applied at a rate of 1.0 mg kg^?1 degraded in the Exeter sandy loam surface and subsurface soils, compared to 40% of applied imidacloprid within 300 days in Drummer surface and subsurface soils. At the 0.1 mg kg^?1 application rate, dissipation was slower for all four soils. Water-extractable imidacloprid in Exeter surface soil decreased from 98% of applied at day 1 to > 70% of the imidacloprid remaining after 400 d, as compared to 55% in the Drummer surface soil at day 1 and 12% at day 400. These data suggest that imidacloprid was bioavailable to degrading soil microorganisms and sorption/desorption was not the limiting factor for biodegradation. In subsurface soils > 40% of ¹⁴C-benzoic acid was mineralized over 21 days, demonstrating an active microbial community. In contrast, cumulative ¹⁴CO₂ was less than 1.5% of applied ¹⁴C-imidacloprid in all soils over 400 d. Qualitative differences in the microbial communities appear to limit the degradation of imidacloprid in the subsurface soils.     

Biochemical interaction of six op delayed neurotoxicants with several neurotargets

Abstract

Five organophosphorous insecticides: Leptophos, EPN, Cyano‐fenphos, trichloronate and salithion proved to cause irreversible ataxia not only to chicken but also to mice and sheep. TOCP was included as a reference. Cyanofenphos blocked the catecholamine B‐receptor binding activity with ³H‐norepinephrine at a level similar to that of the specific inhibitor propranolol in the mouse heart preparation. In the lamb heart preparation, the B‐receptor was more sensitive to Leptophos, salithion and TOCP than to propranolol. The six compounds and their oxons were screened for their in‐vitro inhibition to monamine oxidase (MAO), acetyl cholinesterase (AChE) and neurotoxic esterase (NTE) in the brain of either mouse, lamb or chicken. It is believed that their AChE inhibition stands for their acute toxicity, while NTE inhibition is responsible for their paralytic ataxia.     

土壤中砷的化学平衡

本文比较详细地综述了砷的化学特性,环境背景值及来源和循环,土壤中砷的三大化学平衡即沉淀溶解平衡,氧化还原平衡,吸附解吸平衡,以及微生物对砷的转化。     

Elemental uptake by edible herbs and lettuce (Latuca sativa)

The total concentration of toxic elements (aluminum, cadmium, chromium and lead) and selected macro and micro elements (iron, manganese, copper and zinc) are reported in six leafy edible vegetation species, namely lettuce, spinach, cabbage, chards and green and red types of Amaranth herbs. Although spinach and chards had greater than 125 mv of iron, both the amaranthus herbs recorded > than 320 μ g g^{? 1} dry weight. In both the spinach and chard species, the Mn and Zn levels were appreciable recording > 225 μ g g^{? 1} and 150 μ g g^{? 1} dry weight, respectively. Aluminum concentrations were (in μ g g^{? 1} dry weight) lettuce (10), cabbage (11), spinach (167), chards (65), amaranthus green (293) and amaranthus red (233). All the micro and macro elements and the toxic elements (Ni, Cr, Cd and Pb) elements analyzed, were below the recommended maximum permitted levels (RMI) in vegetables. Further the elemental uptake and distribution of the nine elements, at three growth stages of the lettuce plant grown on soil bed under controlled conditions are detailed. In the soil, except for iron (16%), greater than 33% of the other cations were in exchangeable form. Generally in the lettuce plant, roots retained much of the iron (> 224 μ g g^{? 1}) and aluminum (> 360 μ g g^{? 1}), while leaves had less than 200 μ g g^{? 1} of iron and 165 μ g g^{? 1} of Al. Although the concentrations of elements marginally decreased with growth, the lettuce leaves had significant amounts of Mn (30 μ g g^{? 1}), Zn (50 μ g g^{? 1}) and Cu (3.6 μ g g^{? 1}). Some presence of lead in leaves (2.0 μ g g^{? 1}) was noticed, but all the toxic and other elements analyzed were well below the RMI values for the vegetables.     

The dissipation of nonlyphenol in stream and pond water under simulated field conditions

Abstract

The dissipation of 1.0 ppm nonylphenol in stream and pond water, incubated in flasks at 16°C under simulated field conditions up to 44 days indicated that the half‐life was 2.5 days if the flasks were open, and 16 days if they were closed. A transformed product was detected in the closed flasks.

Translocation of nonylphenol in water occurred when treated water samples were incubated in the presence of sediment. After 10 days, nonylphenol was detected only in the sediment, but not in water (detection limit = 10 ppb). About 80% of the nonylphenol was degraded in 71 days, but no degradation occurred if the water and the sediment were autoclaved prior to incubation.