含有机物铁泥的超临界水氧化法资源化

氨基染料生产过程中产生大量含有机物的铁泥,对环境造成严重污染并造成资源的极大浪费.利用超临界水氧化法对含有机物铁泥进行资源化处理研究,并对产物进行了X射线衍射分析(XRD)、色差实验与电子探针分析.研究结果显示,用超临界水氧化法处理铁泥可以将铁泥中所含的有机物完全氧化,真正实现环境友好;超临界水首先将铁泥氧化成α-Fe2O3与γ-Fe2O3,再经过800℃煅烧后可以作为氧化铁红颜料使用;超临界反应压力对样品的晶型与颜色影响不大.     

氨的超临界水氧化研究进展

在超临界水氧化过程中,氨作为含氮有机物氧化的中间产物,其氧化是有机物在超临界水中氧化降解速率的控制步骤.综述了氧化剂、温度、过氧量、停留时间和催化剂等因素对氨的超临界水氧化降解效果的影响,并总结了目前常用的两种反应动力学模型.与双氧水或氧相比,NO-3氧化荆具有更强的氧化能力;通过提高温度、过氧量和停留时间都可以促进氨的超临界水氧化降解.在氨的超临界水氧化中,当无催化剂作用时,氨的降解率很低;加入MnO2/CeO2等催化剂,可以显著提高氨的降解率.为加快超临界水氧化法处理含氮有机废水的应用进程,未来应侧重氨氧化机制的研究和催化剂的开发.     

组合方法去除新型采油污水中有机污染物的研究

含聚丙烯酰胺采油污水的有效处理是近年来困扰油田三次采油生产的一个难题。研究采用移动床生物膜技术与O3/UV/H2O2高级氧化技术的组合方法来处理含聚丙烯酰胺采油污水。实验结果表明,移动床生物膜技术可以有效去除污水中的石油类有机物,但对聚丙烯酰胺几乎无效果。O3/UV/H2O2高级氧化技术可以降解污水中的聚丙烯酰胺。组合方法处理后的含聚丙烯酰胺采油污水水质可以达到污水综合排放标准中的一级要求。     

城市污水生化处理水UV/O3法深度处理效果及影响因素研究

研究城市污水生化处理水的深度处理技术及其影响因素,对于减轻环境污染和实现废水回用具有重要理论意义和实用价值。考察了UV／O3法对城市污水生化处理水深度处理的效果及其影响因素。结果表明,由于UV／O3过程具有氧化能力强,反应无选择性等优点,使其在城市污水生化处理水深度处理方面较普通O3氧化更具有优势,50min时CODCr去除率达到90％以上,达到了深度处理的目的。对于难氧化有机物,UV／O3法处理时几乎大部分都被氧化分解残留量很少,而O3法处理时仍有较多难氧化有机物残留。UV／O3法处理城市污水生化处理水时,在pH=6～9时,CODCr去除率随pH的升高而降低,表明较低pH（pH=5）有利CODCr的去除。有机污泥对CODCr去除率基本没有影响。但无机悬浮物SiO2对CODCr去除率影响较大,投加70mg／L的SiO2后CODCr氧化速率和去除率有较明显下降。随溶液碱度的增加,CODCr的去除率下降,碱度越高对CODCr去除的影响也越明显。     

高硝酸盐地下水离子交换再生液的生物脱硝及循环利用

离子交换法净化含硝酸盐地下水时产生大量高硝高盐废水,为避免其危害环境,利用添加了不同载体(Ti O2和α-Fe2O3)的耐盐改性颗粒活性污泥,生物反硝化去除含0.5 mol/L氯化钠和0.25 mol/L碳酸氢钠的模拟高硝高盐再生废水中的硝酸盐,生物反应器出水经深度处理过程高效去除水溶性有机物(SOC)、悬浮物及微生物后,循环利用于再生树脂。结果显示,颗粒活性污泥生物反硝化可以处理硝酸盐浓度高达75 mmol/L的再生废盐水,添加α-Fe2O3和添加Ti O2的颗粒活性污泥的反硝化能力分别达2.33和0.93 g NO-3-N/(L·d);生物反应器出水中添加氯化钙形成碳酸钙絮凝体,去除生物反硝化自身所产碱度的同时,絮凝去除67%的水溶性有机物;絮凝后出水经颗粒活性炭过滤和臭氧消毒后,可至少再利用于再生树脂10次而不影响树脂处理含硝酸盐地下水的性能,实现了离子交换树脂再生所产高硝高盐废水的生物脱硝与循环利用。     

TiO2/SiO2/γ-Fe2O3的表征及其光催化降解染料废水

以γ-Fe2O3为磁性核心,通过溶胶-凝胶法制备出三层结构的复合光催化剂TiO2/SiO2/γ-Fe2O3.通过X射线衍射、扫描电镜、透射电镜、振动样品磁强计和紫外-可见分光光谱分析进行表征.SiO2包覆膜可以减弱内层γ-Fe2O3对光催化效果的不利影响,有效地阻隔高温时γ-Fe2O3磁核与TiO2之间的熔结.以亚甲基...     

高级氧化法脱除PVA浆料的清洁生产新工艺研究

为了研究高级氧化法脱除聚乙烯醇(PVA)浆料清洁生产新工艺的可行性,研究了3种高级氧化法UV/H2O2、UV/TiO2、Nafion-Fe2 /H2O2对含PVA溶液的氧化降解,其降解效果依次为:UV/H2O2＞Nafion-Fe2 /H2O2＞UV/TiO2.对于UV/H2O2法,PVA降解速率与H2O2的初始浓度成正相关,且H2O2浓度为2.95 mmol/L时14 min内就能使PVA的去除率达到98%;pH和温度对PVA的氧化降解效果影响不明显.在此基础上,对建立在高级氧化法基础上的退浆新工艺进行了探讨,结果表明,在65℃和75℃下,高级氧化法条件下的纯棉织物PVA退浆率分别达到70.16%和95.65%;该法不仅可以促进PVA从纯棉织物上的脱附,而且可以达到对PVA的较高降解效果,使得所排退浆废水的生化处理难度明显降低.     

基于MOF模板的纳米立方块α-Fe_2O_3水热合成及光催化降解活性测试研究

在无表面活性剂条件下,以普鲁士蓝结构的Fe4(Fe(CN)6)3为前驱体,通过水热法合成了纳米立方块结构的α-Fe2O3,并利用X射线衍射、透射电子显微镜、扫描电子显微镜对产物的形貌进行了表征。同时对其光催化降解活性进行了研究,结果表明,立方体纳米α-Fe2O3可以作为一种新型的光催化剂用于环境有机物的光催化降解。     

酸析-Fenton氧化法处理采气废水

采用酸析-Fenton氧化法对川西某气井采气废水进行降解处理研究,考察了pH、Fenton试剂配比、投加量及反应时间等主要影响因素对采气废水处理效果的影响,并选用气相色谱-质谱仪器(GC-MS)对酸析-Fenton氧化法处理前后水样的成分进行定性分析.结果表明,酸析-Fenton氧化法最佳实验条件:pH为l,H2O2/COD为7,H2O2/Fe2+(摩尔比)为3,反应时间为120 min;在最佳实验条件下COD、SS、油类物质、色度的去除率分别为81％、99％、95％、99％;对比处理前后水样的GC-MS图谱,表明在质谱扫描范围内,处理前后水样中物质成分变化较大,酸析-Fenton氧化技术对采气废水中难降解有机物的去除效果明显.     

催化超临界水氧化对氨基苯酚

采用CuO/γ-Al2O3和MnO2/γ-Al2O3为催化剂、H2O2为氧化剂,在一连续流固定床反应器中进行了超临界水氧化对氨基苯酚实验.实验结果表明,CuO和MnO2催化剂对于对氨基苯酚的氧化降解具有显著的促进作用.对氨基苯酚的去除率随反应温度和压力的升高、停留时间的延长而提高,在24～26 MPa和400～450℃条件下,数秒钟内COD去除率可达到99%以上,催化剂CuO/γ-Al2O3的催化效果优于MnO2/γ-Al2O3.证明了催化超临界水氧化技术的高效性.     

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.     

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.     

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.     

Radionuclides in deer and elk from Los Alamos national laboratory and the doses to humans from the ingestion of muscle and bone

Abstract

This paper summarizes radionuclide concentrations (³H, ⁹⁰Sr, ¹³⁷Cs, ²³⁸Pu, ^239,240Pu, ²⁴¹Am, and ^totU) in muscle and bone tissue of mule deer (Odocoileus hemionus) and Rocky Mountain elk (Cervus elaphus) collected from Los Alamos National Laboratory (LANL), Los Alamos, New Mexico, lands from 1991 through 1998. Also, the committed effective dose equivalent (CEDE) and the risk of excess cancer fatalities (RECF) to people who ingest muscle and bone from deer and elk collected from LANL lands were estimated. Most radionuclide concentrations in muscle and bone from individual deer (n = 11) and elk (n = 22) collected from LANL lands were either at less than detectable quantities (where the analytical result was smaller than two counting uncertainties) and/or within upper (95%) level background (BG) concentrations. As a group, most radionuclides in muscle and bone of deer and elk from LANL lands were not significantly higher (p<0.10) than in similar tissues from deer (n = 3) and elk (n = 7) collected from BG locations. Also, elk that had been radio collared and tracked for two years and spent an average time of 50% on LANL lands were not significantly different in most radionuclides from road kill elk that have been collected as part of the environmental surveillance program. Overall, the upper (95%) level net CEDEs (the CEDE plus two sigma for each radioisotope minus background) at the most conservative ingestion rate (50 lbs of muscle and 13 lbs of bone) were as follows: deer muscle = 0.22 mrem y^‐1 (2.2 μSv y^‐1), deer bone = 3.8 mrem y^‐1 (38 μSv y^‐1), elk muscle = 0.12 mrem y^‐1 (1.2 μSv y^‐1), and elk bone = 1.7 mrem y^‐1 (17 μSv y^‐1). All CEDEs were far below the International Commission on Radiological Protection guideline of 100 mrem y^‐1 (1000 μSv y^‐1), and the highest muscle plus bone net CEDE corresponded to a RECF of 2E‐06, which is far below the Environmental Protection Agency upper level guideline of 1E‐04.     

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.