三维电催化氧化法处理高浓度有机废水

以石墨为阳极,钢板为阴极,主电极板间填充具有特异催化功能和导电性能的铁锰双金属改性活性炭催化剂颗粒,进行三维电催化氧化实验,以处理高浓度有机废水。通过浸渍煅烧法制备了铁锰双金属改性活性炭催化剂,且对催化剂的形貌和结构进行了表征和分析;考察了电压、初始pH、曝气量和反应时间等工艺参数对电催化氧化去除乙腈的影响,再确定最佳实验条件后,考察了三维电催化氧化处理有机废水的稳定性、处理实际有机废水的效果。结果表明：铁锰初始比例为1∶2、煅烧温度为550°C、投加量为300 mg·L^-1、电压为24 V、初始pH为7、曝气量为4L·min^-1时,三维电催化氧化反应60 min处理效果最佳,乙腈去除效率达到96.1%,5次循环实验乙腈去除率仍能保持88.7%。且在处理实际废水中,也能保持高效的去除性能,并能同步去除氨氮。     

改性沸石承载纳米Fe/Ni对水中2,4-二氯苯酚的去除

将通过液相还原法制备的纳米铁/镍(Fe/Ni)颗粒承载于改性沸石表面制得负载型复合材料,纳米Fe/Ni在改性沸石表面具有良好的分散性。复合材料对2,4-二氯苯酚(2,4-DCP)的去除包括吸附和降解两个过程,脱氯降解是主要过程。实验结果表明,25℃时,0.6 g的复合材料对20 mg·L~(-1)的2,4-DCP去除效果达到80%,在酸性条件下,复合材料的去除效果未见明显差异,碱性环境会影响2,4-DCP的去除效果。降解产物苯酚被吸附在材料表面,避免了对水环境的二次污染。     

粉煤灰水热合成Y型沸石及其表征

针对固体废弃物粉煤灰的资源化利用问题,探索合成Y型沸石的实验方法。以燃煤锅炉产生的粉煤灰为实验对象,经过筛分、研磨、高温煅烧和酸浸等预处理方法来提高硅铝含量。将预处理后的粉煤灰加碱煅烧后与氢氧化钠水溶液混合,水热合成Y型沸石。结果表明:粉煤灰经过750℃煅烧1.5 h可以去除约15%的碳;用4 mol·L~(-1)的盐酸在90℃下处理2 h,粉煤灰中的铁、钙和硫等杂质可以分别减少约63.1%、87.3%和79.6%;粉煤灰预处理后的质量减少约51%;预处理后的粉煤灰经过加碱熔融处理,其中的石英和莫来石晶相物质被完全破坏,生成了新的晶相物质;当预处理粉末/碱的质量比为1∶1.2时,熔融产物经过水热反应(温度95~105℃、时间12~24 h)可以生成纯度良好、形貌规则的八面棱柱体Y型沸石;粉煤灰合成Y型沸石的BET等效比表面积可达389.44 m~2·g~(-1),孔容为0.348 mL·g~(-1),并具有优良的热稳定性。粉煤灰经过适当处理,可以在不外加硅、铝化学试剂以及模板剂情况下水热合成结晶度良好的Y型沸石。     

用作固定SRB碳源的玉米芯的最佳改性条件

针对现阶段玉米芯作为SRB污泥颗粒内聚碳源所带来碳源释放不佳的问题,选用碱性H_2O_2对玉米芯进行改性,制备成SRB污泥颗粒处理AMD,经过单因素实验和正交实验分析,对玉米芯的最佳改性条件进行研究。结果表明,当玉米芯改性时间24 h,NaOH浓度为6%,H_2O_2浓度为1.5%,可制得最佳改性玉米芯。制备成SRB污泥颗粒处理AMD后,SO_4~(2-)、Mn~(2+)和Fe~(2+)去除率分别为93%、78%和95%,较未改性提高了29%、3%和23%;COD释放量为215 mg·L~(-1),较未改性减少了545 mg·L~(-1);Fe~(2+)剩余量为1.5 mg·L~(-1),较未改性减少了1.1 mg·L~(-1);溶液pH为7.8。同时经SEM和XRD分析,发现改性玉米芯颗粒较未改性玉米芯颗粒相比,内部结构变得的疏松多孔,且大分子物质被分解为小分子物质,可以更好被SRB所利用。说明了该改性法可以改善玉米芯的碳释性能,为微生物处理AMD的工程应用提供技术参考。     

改性生物质炭与聚磷菌联合去除废水中的磷

为了探索改性生物质炭与聚磷菌联合去除废水中磷的效果,将铁改性生物质炭以及聚磷菌投加入序批式废水处理装置中,间隙进水,间隔一定时间测定水中磷浓度随时间变化,并探讨不同水力停留时间、进水COD浓度以及初始磷浓度对联合除磷的影响。研究结果表明,铁改性生物质炭和聚磷菌联用能高效去除废水中磷,在30℃、水力停留时间6h、COD浓度280 mg·L~(-1)、初始磷浓度5 mg·L~(-1)并且持续曝气条件下,联合除磷效果最优,其磷去除率可达97.94%。铁改性生物质炭和聚磷菌联合能有效去除废水中磷,为废水除磷提供了新技术。     

玉米芯为碳源固定化硫酸盐还原菌污泥代谢特性

以聚乙烯醇为包埋载体,饱和硼酸为交联剂,制作了玉米芯为内聚缓释碳源的固定化硫酸盐还原菌污泥颗粒。通过厌氧批实验研究了在模拟酸性矿山废水(AMD)条件下玉米芯含量、初始SO2-4和Mn2+负荷以及p H对固定化颗粒代谢特性的影响,初步分析了固定化颗粒处理AMD的机理及可行性。实验结果表明,玉米芯在微生物作用下快速水解并产生有机物累积后,固定化颗粒才能迅速还原SO2-4,且玉米芯含量≤5%时硫酸盐还原率与玉米芯含量成正相关,玉米芯的水解会略微降低体系的p H;初始SO2-4浓度通过改变体系中COD/SO2-4和颗粒内外的浓度差影响固定化颗粒的代谢过程,而对玉米芯水解的影响不显著。初始p H为2~6和Mn2+浓度≤55 mg/L时对固定化颗粒活性抑制作用不明显,初始p H越低越利于玉米芯的水解和颗粒形成良好的孔隙结构;颗粒对Mn2+的去除机理是一种不依赖微生物活性的快速化学吸附作用,可用伪二级动力学模型描述吸附过程(R2=0.995)。     

滤材的表面改性对淤泥脱水过程中渗透性能的影响

滤布是淤泥脱水过程中重要的过滤材料,实验选用5种滤布(3927、621、758、750A、750B)作为淤泥脱水过程中的过滤材料,探究了滤布种类对淤泥脱水过程中渗透性能的影响,并通过扫面电镜观察淤泥在不同滤布表面的附着情况,基于最佳滤布,引入织物平滑剂、毛毯柔软剂及氟表面活性剂等3种表面活性剂并采用自然干燥和烘箱烘干等2种不同干燥方式改性滤布,通过测定表面接触角表征改性后滤布表面亲疏水性能,并探究了不同表面活性剂种类及干燥方式所得改性滤布对淤泥脱水过程中渗透性能的影响,最后通过扫描电镜对比改性前后750B滤布负载过滤后淤泥颗粒附着情况。结果表明,滤布750B作为过滤材料时淤泥渗透性能最佳。对比6种改性方式所得改性750B滤布,采用氟表面活性剂改性并在烘箱中105℃烘2 h所得改性滤布在负载过滤实验中所得渗透系数及渗水量最大,渗透性能大幅提升。     

改性活性炭负载二氧化钛催化双氧水处理污水

采用酸碱两步对活性炭表面进行改性处理,通过Boehm滴定、扫描电镜、傅里叶红外光谱等测定方法对改性前后活性炭进行表征。结果表明,改性前后活性炭表面结构和官能团数量均发生了变化;以改性活性炭(GAC)负载二氧化钛为催化剂催化双氧水处理污水能有效提高COD的去除效果。     

微电解联合物化法处理维生素B12难降解废水的研究

对使用微电解联合物化法处理维生素B12难降解废水进行了分析。通过实验研究了微电解联合物化法处理维生素B12废水的最佳工艺条件。在最佳工艺条件下,维生素B12废水色度去除达88.46%,COD去除率达到71.06%。该处理方法最后将污染物质直接吸附于改性膨润土上,不产生浓缩废水、酸碱废水等更加难以处理的废水,并且不带入有毒有害物质,可以有效降低水中污染物含量,减少后续生物处理设备的污染负荷。     

煤矸石热活化性能研究

系统地研究了徐州夹河煤矸石在不同煅烧温度下的物理、化学变化及活性成分的溶出规律.采用扫描电子显微镜(SEM)、差热分析(DTA)、X射线衍射(XRD)等测试方法研究了热活化前后煤矸石的矿物组成、SiO2及Al2O3溶出率和微观结构,并采用水泥强度的测试方法对热活化煤矸石的活性进行宏观表征.结果表明,煅烧能有效去除有机挥发物和碳.破坏煤矸石中的硅氧键、铝氧键,形成无定形物质和玻璃相,从而提高煤矸石的活性.徐州夹河煤矸石的最佳热活化工艺条件是煅烧650℃、保温2 h.经此条件热活化后,SiO2和Al2O3的最高溶出率分别是76.32%、91.48%,添加50%(质量分数)的热活化煤矸石到水泥中,其强度比同掺量原样煤矸石的水泥强度提高了230%.     

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.