废旧线路板真空热解油合成热固性酚醛树脂

以废旧线路板真空热解油为原料,NaOH为催化剂,与甲醛的缩聚反应合成热固性酚醛树脂(TPR),重点考察了合成条件对产物固含量的影响。结果表明,合成热固性酚醛树脂的最佳条件为:每38.5 g热解油加入甲醛、催化剂分别为40 g、10 g,第1阶段温度为60℃、反应时间为3 h,第2阶段温度为95℃、反应时间按为3 h,其中催化剂的加入量是最主要的影响因素。通过红外光谱分析(IR)及热重分析(TG)测定了合成产物的结构和性能,并对产物进行了力学性能的检测。结果证明,以热解油为原料合成的酚醛树脂出现了CH2、CH—OH等特征峰,且产物的耐热温度在300℃以上,拉伸强度达到了39.6 MPa,与以苯酚为原料合成的酚醛树脂相近,研究结果表明,真空热加油为原料合成酚醛树脂是可行的。     

酚醛树脂胶粘剂生产废水的物化前处理

采用酸性二步缩合-混凝法，对ρ(CODcr)=70224mg／L，ρ(挥发酚)=14200mg,／L，P(甲醛)=7480mg/L的酚醛树脂胶粘剂生产废水进行了物化前处理试验研究。第一步采用酚醛缩合方法，第二步采用脲醛缩合方法，通过试验确定了各步的缩合剂用量和工艺条件，经物化前处理的废水，CODcr去除率达79％以上，挥发酚和甲醛去除率达到99％以上，为后续处理创造了条件；缩合处理每吨废水可回收树脂16．25kg，有效地降低了处理费用。     

盐析-冰冻法预处理高浓度酚醛树脂废水

对于COD值为131 200 mg·L~(-1),苯酚浓度值为45 600 mg·L~(-1),甲醛浓度值为1 500 mg·L~(-1)的酚醛树脂废水,通过显微镜观察得知以苯酚为主的有机组分以稳定乳化状态存在。采用盐析-冰冻法对酚醛树脂废水进行破乳处理的实验研究表明,添加35%Na Cl、在-7℃条件下进行冰冻处理后,废水COD值和苯酚浓度值、甲醛浓度值分别降至28 720、6 310和1 359 mg·L~(-1),去除率分别为78.11%、86.16%和9.40%,实验证明盐析-冰冻法预处理酚醛树脂废水可行。     

缩聚-Fenton-A/O生物流化床组合工艺处理酚醛废水的工程案例分析

以广州某公司生产酚醛树脂时产生的酚醛废水为研究对象,针对其高浓度、生物毒性强、可生化性差及难降解等特点,设计缩聚-Fenton-A/O生物流化床联合工艺进行处理。此工艺的工程实践中,在总HRT低于75 h的操作条件下,当进水COD、苯酚及甲醛浓度分别为1.0×105～1.2×105 mg/L、2.2×104～2.5×1...     

ZnO/TiO_2光催化剂的制备及太阳光催化降解苯酚的研究

以溶胶-凝胶法和等体积浸渍法制备了ZnO/TiO_2光催化剂(分别表示为SG-w%ZnO/TiO_2、JZ-w%ZnO/TiO_2,其中w%为ZnO占TiO_2的质量分数),采用X射线衍射(XRD)、红外光谱(IR)、紫外—可见吸收光谱(UV-Vis)和扫描电子显微分析镜(SEM)-能量弥散X射线谱(EDS)表征了各光催化剂的物相结构,考查了光催化剂制备方法、ZnO掺杂量、焙烧温度、苯酚初始浓度、降解时间对太阳光催化降解苯酚活性的影响,并探讨了太阳光催化降解苯酚的反应机理。结果表明:(1)500℃下煅烧2h制备的SG-0.5%ZnO/TiO_2、JZ-0.5%ZnO/TiO_2中TiO_2均以锐钛矿相存在,ZnO掺杂有利于提高光催化剂的太阳光催化性能。(2)在太阳光照射4h、光催化剂用量为2g/L、苯酚初始质量为10 mg/L的条件下,JZ-0.5%ZnO/TiO_2对苯酚的降解率可达61%,优于商用TiO_2(P25)。     

烧结脱硫灰制备蒸压加气混凝土砌块的研究

研究了烧结烟气半干法脱硫灰复掺粉煤灰、水渣/水泥,辅之外加剂,制备蒸压加气混凝土砌块的可行性.实验结果显示,当脱硫灰掺入量25%,粉煤灰掺入量45%,水渣和水泥掺入量均15%,铝粉掺入量0.04%,水料比0.6,稳泡剂掺入量0.0012%,烧碱掺入量1%,无需额外添加石膏,采用蒸压养护12.5 h(其中抽真空时间为0....     

钴铜铁三元类水滑石材料催化过硫酸氢钾复合盐降解苯酚

采用共沉淀法制备过渡金属钴、铜、铁组成的钴铜铁三元类水滑石材料(CoCuFe-LDH),用于催化过硫酸氢钾复合盐(PMS)降解水中苯酚,并考察了初始pH、CoCuFe-LDH催化剂投加量、PMS用量对苯酚降解效率的影响。实验结果表明:CoCuFeLDH对PMS的催化活性较高;在pH为中性,催化剂为0.20g/L,PMS为2.5mmol/L,苯酚为50mg/L的条件下处理60min,苯酚的去除率可达96%;当催化剂投加量分别为0.05、0.10、0.15g/L,反应40min时,苯酚的去除率分别为76%、82%和91%。自由基猝灭实验表明,CoCuFe-LDH/PMS催化体系中存在硫酸根自由基和羟基自由基,但硫酸根自由基为主要活性自由基。     

污泥-烟煤基活性炭的制备及其对苯酚的吸附性能

以石化企业在污水处理过程中产生的干化剩余污泥为原料,大同烟煤作辅助添加料,采用化学活化法制备污泥-烟煤基活性炭,探讨了活化剂(ZnCl_2)用量、活化温度、活化时间等条件对所制备的活性炭性能的影响。以活性炭的碘吸附值为衡量指标,当污泥∶烟煤(质量比)=1∶1时获得制备污泥-烟煤活性炭的最佳工艺条件为:浸渍液为ZnCl_2∶原料(质量比)=2∶1,活化温度550℃,活化时间30 min,在该条件下制备的活性炭的碘吸附值为990 mg·g~(-1),比表面积为836m~2·g~(-1),产率为46.6%。同时,以苯酚为目标污染物,考察了所制备的污泥-烟煤基活性炭对苯酚的去除效果,结果表明:污泥-烟煤基活性炭投加量为2.0 g·L~(-1)时,4 h后达到吸附平衡,离子强度对吸附容量没有显著的影响,溶液pH在4~10范围内对苯酚有较好吸附,pH=6时苯酚吸附容量为138.9 mg·g~(-1)。与同类吸附剂相比,制备的污泥-烟煤基活性炭可高效吸附水溶液中的苯酚。     

溶胶-凝胶法制备稀土Gd掺杂SnO2电催化电极的实验研究

本实验采用溶胶-凝胶法,以无机盐SnCl4·5H2O、Sb2O3、Gd(NO3)3为前驱体,制备稀土(Gd)掺杂Sn、Sb溶胶,以钛电极为基材利用该溶胶制备稀土(Gd)掺杂SnO2涂层电极.优化了溶胶-凝胶法制备稀土Gd掺杂SnO2涂层电极的实验条件,研究了在不同加水量、柠檬酸量、pH值等条件下所制备的电极以苯酚为目标有机物的电化学降解特性,对所获得的电极进行了TOC测试及SEM、XRD和XPS等表征,分析并讨论了稀土掺杂对SnO2电极性能的影响机理.结果表明,溶胶-凝胶法制备稀土掺杂SnO2涂层电极是可行的,稀土Gd的掺杂有利于SnO2电极电催化性能的提高,而且不同的加水量、柠檬酸量、pH值对电极性能有一定的影响.本实验条件下,加水量(水与前驱体总量摩尔比)R为36、柠檬酸加入量(柠檬酸与前驱体总量之摩尔比)N为1.0、溶胶pH值为2时所制备的电极降解效果最好,电极最稳定.所获得的电极为纳米涂层电极,其表面涂层中SnO2、Gd2O3等催化活性物质的含量均较高,对苯酚的降解有较好的效果.     

沙雷氏苯酚降解菌固定化条件优化及降解性能研究

从首都钢铁集团焦化厂曝气池中的活性污泥中分离出一株沙雷氏菌属,利用聚乙烯醇(PVA)-卡拉胶混合载体对该菌种进行固定化,并对实际焦化废水进行降解。结果表明:(1)以PVA为包埋材料,添加卡拉胶为辅助载体后,使得固定化苯酚降解菌小球在制备过程中不易出现凝集的现象,易于操作,固定化苯酚降解菌小球颗粒综合性能有所提高。(2)最佳的固定化条件:PVA质量分数为8%,卡拉胶质量分数为0.5%,KCl为0.4mol/L,菌体化包埋比(菌液和混合载体的体积比)为1.0∶5.0,固定化时间为24h。新制备的固定化苯酚降解菌在使用前需进行活化,以提高降解性能。(3)在焦化废水的实际降解中,固定化苯酚降解菌的降解性能明显优于游离苯酚降解菌,固定化的载体对固定于其中的菌种起到了保护作用。     

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.     

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.     

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.     

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.     

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.     

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.     

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 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.