聚合物强化超滤处理含铜废水

聚合物强化超滤工艺（PEUF）是一种将高分子聚合物和超滤技术结合的新型、高效的重金属废水治理方法。以壳聚糖（CTS）为聚合物去除水中的铜离子。考察了吸附络合和超滤过程中影响铜去除率的多种因素。结果表明,溶液pH值为6.0、CTS浓度为0.15 g/L和反应时间为60 min时,通过超滤系统后效果最佳。装载比一定时,铜初始浓度的变化对铜的去除率没有明显影响。CTS对铜的吸附过程符合Langmuir吸附等温方程。还研究了超滤膜的污染情况和膜清洗方法,结果表明,酸清洗效果较好,可使膜通量恢复达87%左右。     

镁铝类水滑石原位共沉淀法处理含镍模拟废水的研究

通过原位共沉淀法处理含镍模拟废水,探讨了反应时间、体系pH、镍与镁的摩尔比(Ni/Mg)、二价离子与三价离子的摩尔比((Ni+Mg)/Al)和Ni 2+初始浓度对Ni 2+去除效果的影响。实验结果表明,Ni 2+能通过镁铝类水滑石原位共沉淀法被除去。体系pH、Ni/Mg、(Ni+Mg)/Al和Ni 2+初始浓度均对Ni 2+去除率影响较大,而反应时间对其影响不大。在反应时间为1～2h、pH=8.5、Ni/Mg=0.25、(Ni+Mg)/Al=2.0时,可获得最高的Ni 2+去除率(99.84%),产物经X射线衍射(XRD)分析确定具有层状双氢氧化物(LDHs)结构。     

络合-陶瓷膜耦合技术资源化处理模拟低浓度含铜废水

以聚丙烯酸(PAA)和壳聚糖(CTS)作为络合剂,耦合孔径200 nm的陶瓷膜处理模拟低浓度含铜废水,采用ICP-MS、TOC、SEM表征与Darcy膜污染模型对处理效果和膜污染情况进行表征;对比研究不同络合剂对Cu~(2+)截留效果与资源化回用效率的影响;并探讨对应的膜污染机理。结果表明:溶液pH通过影响聚合物络合活性位点对Cu~(2+)截留率起决定性作用;在pH=6、P/M≥5或C/M=10的优化条件下,Cu~(2+)截留率接近100%;PAA相对于CTS对Cu~(2+)的络合效率更高,而CTS具备更好的抗杂质离子干扰能力;酸解、循环回用的PAA与CTS对Cu~(2+)截留率稳定在99%以上。膜污染阻力分布计算和SEM、EDX微观表征表明,滤饼污染为膜污染主要形式,CTS更易造成不可逆的膜孔堵塞污染。     

菌丝体—甲壳素水处理剂对重金属Ni^2＋离子吸附性能的研究

本文系统研究了菌丝体－甲壳素（甲壳素）作为水处理剂对去除水体中Ni^2 离子时的吸附特性，结果表明，甲壳素作为水处理剂，在较大pH值变化范围内，对Ni^2 离子与柠檬酸镍都有较高的吸附容量；甲壳素在吸附金属离子的同时，对H^ 有吸附作用，且H^ 是金属离子的竞争性抑制剂。将甲壳素与市售吸附树脂相比，其对阳离子（Ni^2 ）和络阴离子（柠檬酸镍Ni(cit)^2-）的吸附特性类似于阳离子交换树脂。同时，甲壳素不会带来二次污染，是一种具有广泛应用前景的环保型工业水处理剂。     

酸根离子对铝板电絮凝处理含镍废水的影响

电絮凝是去除废水中重金属离子的有效技术。本研究考察了常见酸根离子SO2-4、Cl-、NO-3和H2PO-2对铝板电絮凝除Ni2+的影响。结果表明,SO2-4、Cl-、NO-3均有利于Ni2+的去除,其中由于NO-3的还原可提高铝阳极溶解效率,因此,当其浓度从0.0186增至0.186 mol/L时,反应30 min后Ni2+去除率从77.9%升至99.8%。H2PO-2会降低絮体絮凝活性并钝化电极,从而显著降低Ni2+去除率,其浓度从0.0186 mol/L增至0.372 mol/L,反应60 min后Ni2+去除率从91.7%降至30.5%。另外,对各阴离子存在下溶解态铝絮体聚合度以及电解过程pH的检测,进一步揭示这4种离子对电絮凝影响机制。     

极水室填充树脂对电去离子过程浓缩低浓度NiSO4溶液的影响

以低浓度NiSO4溶液为处理对象,考察了极水室树脂填充对EDI膜堆电阻、极限电流以及电极水pH的影响情况,并对EDI分离性能进行了考察。结果表明,实验条件下,极水室填充树脂后膜堆的极限电压由6 V提高到10 V,对应的极限电流从0.213 A提高到0.421 A。对于含Ni2+离子50 mg/L的NiSO4溶液,EDI浓缩产品水Ni2+浓度达到14 224mg/L,浓缩倍数280倍;淡水出水中Ni2+浓度为3.45 mg/L,Ni2+脱除率为93%。实验范围内,EDI运行稳定,未产生Ni(OH)2结垢。     

垃圾焚烧发电厂渗滤液MBR-NF截留液中腐植酸的超滤分离回收

垃圾焚烧发电厂渗滤液MBR-NF膜截留液因含有高浓度的难降解有机物和无机盐而难以处理。考虑其所含有机物大部分为腐植酸,可加于资源利用。本研究采用超滤对MBR-NF膜截留液中的腐植酸进行分离回收。实验结果表明,超滤能有效分离截留液中有机物和无机盐离子,分离因子与体积浓缩倍数(CF)呈良好的线性关系;回收样品的腐植酸含量达到36 g/L以上,重金属含量低于相关标准限值,表明采用超滤分离回收垃圾焚烧发电厂渗滤液MBR-NF截留液中的腐植酸是可行的。     

胶团强化超滤法(MEUF)去除废水中氯苯的研究

研究了3种单一表面活性剂十二烷基硫酸钠(SDS)、十六烷基三甲基溴化铵(CTMAB)、聚氧乙烯失水山梨脂肪酸酯醇醚(TW80)和混合表面活性剂TW80-SDS对氯苯(CB)的强化超滤,以期为有机废水胶团强化超滤技术提供参考。结果表明,进料液静置时间对去除率无显著影响,而振荡时间在1 h后对去除率影响不大。氯苯的去除率随进料液中表面活性剂浓度的增大而增大,单一的表面活性剂对氯苯的去除效果顺序为TW80CTMABSDS,且表面活性剂对氯苯的去除效果与表面活性剂的临界胶束浓度值(CMC)、亲水-亲油平衡值(HLB)呈负相关。阴-非混合表面活性剂TW80-SDS对氯苯的去除效果明显强于单一的SDS,且去除率随着非离子表面活性剂质量分数的增加而增加。渗透通量随着进料液中表面活性剂浓度的增加而下降,单一表面活性剂种类对渗透通量的影响顺序为SDSTW80CTMAB,混合表面活性剂中随着非离子表面活性剂质量分数的增加而渗透液的渗透通量越低。     

UV/H_2O_2协同光降解处理酒石酸镍废水

含镍电镀废水中酒石酸的存在,使得废水中总镍无法通过化学沉淀法去除,无法满足达标排放要求。采用UV/H_2O_2光降解法处理酒石酸镍体系废水,考察了不同反应p H值、过氧化氢投加量、光照时间对酒石酸镍体系络合废水的处理效果。实验结果表明:UV/H_2O_2法对酒石酸镍体系废水有很好的协同处理效果,光降解过程呈拟一级动力学过程;优化的酒石酸镍废水处理工艺为反应p H值3.0,30%过氧化氢投加量2 m L·L~(-1),15 W功率紫外灯光照下反应120 min,在优化的工艺条件下,采用化学沉淀法去除水中镍,处理后电镀废水中总镍可满足《电镀污染物排放标准》(GB 21900-2008)中0.5 mg·L~(-1)要求。     

改进分光光度法测Ni以规避大量干扰离子

为测定含大量干扰离子的水样中镍的浓度,提出一种改进的分光光度法。即以多种物质的吸光曲线回归方程,将实时测得的水样吸光度分解成多种物质的吸光度,利用多元一次方程进行求解并计算出浓度的方法。新方法在不进行修正时,对含Cr6+干扰的水样Ni2+测定的结果,误差较小。多组分的水样测量吸光度误差较大,通过引入修正系数修正后误差大幅下降。方法中Ni2+、Fe3+的吸光度与显色时间基本无关;而对于Mn2+、Cu2+和Cr6+,显色时间应控制在0.5～2.5 min内或10 min外,以保证测得吸光度值的稳定与准确。对组成不同的含Mn2+和Fe3+水样测得的Ni2+浓度分析,变异系数(CV)4.74%,检出限为0.275 mg/L,精确度和精密度较好。同时,这种规避方法还具有其他作用,可以在分析组分的同时粗略算出含量。     

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.     

Radionuclides and trace elements in fish collected upstream and downstream of Los Alamos national laboratory and the doses to humans from the consumption of muscle and bone

Abstract

The purpose of this study was to determine radionuclide and trace element concentrations in bottom‐feeding fish (catfish, carp, and suckers) collected from the confluences of some of the major canyons that cross Los Alamos National Laboratory (LANL) lands with the Rio Grande (RG) and the potential radiological doses from the ingestion of these fish. Samples of muscle and bone (and viscera in some cases) were analyzed for ³H, ⁹⁰Sr, ¹³⁷Cs, ^totU, ²³⁸Pu, ^239,240Pu, and ²⁴¹Am and Ag, As, Ba, Be, Cr, Cd, Cu, Hg, Ni, Pb, Sb, Se, and Tl. Most radionuclides, with the exception of ⁹⁰Sr, in the muscle plus bone portions of fish collected from LANL canyons/RG were not significantly (p<0.05) higher from fish collected upstream (San Ildefonso/background) of LANL. Strontium‐90 in fish muscle plus bone tissue significantly (p<0.05) increases in concentration starting from Los Alamos Canyon, the most upstream confluence (fish contained 3.4E‐02 pCi g^‐1 [126E‐02 Bq kg^‐1]), to Frijoles Canyon, the most downstream confluence (fish contained 14E‐02 pCi g^‐1 [518E‐02 Bq kg^‐1]). The differences in ⁹⁰Sr concentrations in fish collected downstream and upstream (background) of LANL, however, were very small. Based on the average concentrations (±2SD) of radionuclides in fish tissue from the four LANL confluences, the committed effective dose equivalent from the ingestion of 46 lb (21 kg) (maximum ingestion rate per person per year) of fish muscle plus bone, after the subtraction of background, was 0.1 ± 0.1 mrem y^‐1 (1.0 ± 1.0 μSv y^‐1), and was far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem y^‐1 (1000 μSv y^‐1). Of the trace elements that were found above the limits of detection (Ba, Cu, and Hg) in fish muscle collected from the confluences of canyons that cross LANL and the RG, none were in significantly higher (p<0.05) concentrations than in muscle of fish collected from background locations.     

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.     

Sorption and predicted mobility of herbicides in Baltic soils

This study was undertaken to determine sorption coefficients of eight herbicides (alachlor, amitrole, atrazine, simazine, dicamba, imazamox, imazethapyr, and pendimethalin) to seven agricultural soils from sites throughout Lithuania. The measured sorption coefficients were used to predict the susceptibility of these herbicides to leach to groundwater. Soil-water partitioning coefficients were measured in batch equilibrium studies using radiolabeled herbicides. In most soils, sorption followed the general trend pendimethalin > alachlor > atrazine～ amitrole～ simazine > imazethapyr > imazamox > dicamba, consistent with the trends in hydrophobicity (log K_ow) except in the case of amitrole. For several herbicides, sorption coefficients and calculated retardation factors were lowest (predicted to be most susceptible to leaching) in a soil of intermediate organic carbon content and sand content. Calculated herbicide retardation factors were high for soils with high organic carbon contents. Estimated leaching times under saturated conditions, assuming no herbicide degradation and no preferential water flow, were more strongly affected by soil textural effects on predicted water flow than by herbicide sorption effects. All herbicides were predicted to be slowest to leach in soils with high clay and low sand contents, and fastest to leach in soils with high sand content and low organic matter content. Herbicide management is important to the continued increase in agricultural production and profitability in the Baltic region, and these results will be useful in identifying critical areas requiring improved management practices to reduce water contamination by pesticides.