N-甲基二乙醇胺/哌嗪/羟乙基乙二胺三元复合溶液捕集烟气中CO2中试研究

化学吸收法是目前烟气回收CO2技术的研究热点,其中一类重要的吸收剂就是醇胺复合溶液.醇胺复合溶液具有对CO2吸收速率快、吸收容量大及再生简单的特点,成为烟气CO2吸收剂的首选.采用中试连续实验装置,以N-甲基二乙醇胺(MDEA)/哌嗪(PZ)/羟乙基乙二胺(AEEA)(摩尔比为0.70:0.15:0.15)三元复合溶液为吸收剂对烟气中CO2进行吸收处理.研究结果表明,吸收剂最佳摩尔浓度为3.0 mol/L,最佳吸收温度为40℃,最佳液气比为10 L/m3;再沸器的热负荷随着吸收温度、吸收剂浓度以及液气比的增加而增大,脱碳率随着入口烟气中CO2浓度的增加而降低.     

醇胺溶液吸收与解吸CO2的研究

在温度333K、常压条件下,在羟乙基乙二胺(AEE)总量一定的溶液中,研究了不同浓度AEE对CO2的吸收性能;在总胺质量分数为40%的溶液中,研究了不同配比的AEE N-甲基二乙醇胺(MDEA)对CO2的吸收性能.考察了吸收过程中吸收速率、吸收量、吸收时间、AEE浓度以及吸收液温度的相互关系.控制解吸过程温度为393K,考察了CO2解吸量与解吸时间的关系.实验表明,适当降低AEE浓度有利于充分发挥AEE溶液的CO2吸收性能;在MDEA溶液中加入适量AEE,可以明显提高CO2的吸收与解吸性能;其中质量分数为20?E 20%MDEA的复合溶液在CO2吸收与解吸过程中表现出良好的实际操作性.     

低浓度硫化氢废气的液相催化氧化法净化实验研究

针对H2S浓度为750~1500mg/m3的气体的液相催化氧化技术进行了动力学实验研究。配制了以铁基离子作为主催化剂的复合吸收净化溶液,同时加入稳定剂和表面活性剂提高催化剂在碱性吸收溶液的活性。分别考察了原料气中H2S、O2含量以及吸收液中催化剂离子浓度、温度等因素对吸收速率的影响;确定了较为理想的吸收操作条件并获得了较好的吸收净化效果;饱和吸收液易于再生,净化性能恢复良好,可重复使用。     

乙醇胺/N-甲基二乙醇胺/三乙烯四胺体系吸收烟气CO_2的研究

在乙醇胺(MEA)/N-甲基二乙醇胺(MDEA)体系(简称二元复合胺体系)中加入少量活化剂三乙烯四胺(TETA),研究了MEA/MDEA/TETA三元复合胺体系(简称三元复合胺体系)对烟气CO2的吸收和再生情况。结果表明,MEA、MDEA、TETA3种组分之间存在交互作用,使得三元复合胺体系中的CO2吸收速率、CO2饱和吸收量均分别小于二元复合胺体系与TETA单体系的CO2吸收速率、CO2饱和吸收量之和。三元复合胺体系的再生温度稍高于二元复合胺体系,其一次再生率约为83.5%,比二元复合胺体系低了约13百分点,三元复合胺体系的再生较二元复合胺体系更困难。     

低浓度硫化氢废气的液相催化氧化法净化实验研究

针对H2S浓度为750～1500 mg/m^3的气体的液相催化氧化技术进行了动力学实验研究.配制了以铁基离子作为主催化剂的复合吸收净化溶液,同时加入稳定剂和表面活性剂提高催化剂在碱性吸收溶液的活性.分别考察了原料气中H2S、O2含量以及吸收液中催化剂离子浓度、温度等因素对吸收速率的影响;确定了较为理想的吸收操作条件并获得了较好的吸收净化效果;饱和吸收液易于再生,净化性能恢复良好,可重复使用.     

Fe(Ⅱ)EDTA络合吸收-铁粉还原再生脱除NO性能

利用Fe(Ⅱ)EDTA络合吸收-铁粉间歇还原再生脱除NO并回收氨资源的方法,实验研究了铁粉还原再生Fe(Ⅱ)(NO)EDTA的过程及其影响因素。结果表明,以0.015 mol/L的Fe(Ⅱ)EDTA做吸收剂,在起始p H 5.5、温度323K条件下吸收400×10-6~500×10-6的NO,脱除率95%以上;铁粉还原再生Fe(Ⅱ)(NO)EDTA过程可用缩芯模型阐释;铁粉添加量与搅拌强度直接决定了铁粉质点数量,是影响反应的重要因素;实验中Fe(Ⅱ)(NO)EDTA络合液150 m L,氧气含量为5%时,搅拌速度900 r/min、粒径为0.12 mm的铁粉浓度5.3 g/L、温度353 K、p H=6为最适宜再生条件。     

混合胺MEA+DETA吸收CO2的影响因素

以MEA为主体,DETA 为添加剂,考察1 h内,在温度298~338 K,压力300~700 kPa,混合胺溶液初始浓度(质量分数)4%~20%范围内,MEA+DETA不同配比的混合吸收剂吸收CO₂的特性。获得MEA+DETA混合胺吸收CO₂的最佳吸收条件为:308 K、500 kPa、总胺质量浓度为20%,MEA与DETA 的配比为8:2。     

Cu-Cd、Zn-Cd、Cu-Zn复合污染对水稻毒性和重金属吸收的影响

以"中花11号"水稻品种为研究对象,通过溶液培养探讨了不同浓度配比的Cu-Cd、Zn-Cd、Cu-Zn对水稻根相对伸长毒性及元素吸收的影响。结果表明,Cu、Cd、Zn浓度与水稻相对根伸长均符合剂量效应关系,3种金属离子对水稻毒性次序为CuCdZn;在重金属总量为50%的毒性效应浓度(EC50)下,Cu-Cd对水稻毒性因浓度配比不同而表现不同的作用方式,而Zn-Cd、Cu-Zn对水稻毒性均表现出拮抗作用。在Cu-Cd复合处理下,Cd的加入促进了水稻对Cu的吸收,而Cu的加入对水稻幼苗的Cd吸收表现出不同作用;在Zn-Cd复合处理中,不同浓度Zn的加入均抑制Cd的吸收,使得水稻幼苗中Cd含量降低了9.1%~48.4%;Cu-Zn复合处理中,高浓度Cu的加入(EC40、EC30、EC25)抑制水稻对Zn的吸收。Zn-Cd拮抗作用主要和Zn抑制了水稻对Cd的吸收有关,而Cu-Zn的拮抗作用可能和高浓度的Cu抑制了Zn的吸收有关。     

吸附饱和活性炭的Fenton试剂再生

颗粒活性炭吸附有机废水中二异丙基苯等有机物后,采用Fenton试剂对活性炭进行氧化再生。研究H2O2与Fe2＋的摩尔配比及投加量、pH、温度、再生时间等因素对活性炭再生效果的影响。实验结果表明,Fenton体系中Fe2＋和H2O2的摩尔比为1：20,H2O2投加量为120mmol／L,pH为3,再生温度为25℃,再生时间为70min时,为最佳再生条件,再生率可达85．6％,且6次连续再生的平均效率仍能达到84．9％。Fenton试剂再生活性炭的方法表现出较高的经济和环境效益。     

新型吸收剂净化吸收甲苯废气的实验研究

选择柠檬酸钠水溶液、Tween-20水溶液、檬酸钠-Tween-20混合水溶液、新型矿物油及新型矿物油-水作为研究对象,实验研究对比了几种吸收剂对甲苯废气的吸收效果。通过实验分析可知,檬酸钠水体系对甲苯废气吸收能力有限,加入盐类可小幅增强其水体系对于甲苯废气的吸收效果,其中Tween-20水溶液吸收剂对甲苯废气吸收率较柠檬酸钠水体系高;新型矿物油对甲苯废气有着较好的处理效果,吸收率最高可达97%,而新型矿物油-水混合吸收剂中单位体积新型矿物油对甲苯废气吸收率较新型矿物油吸收剂提高45%,且具有吸收效率高、分散性好、再生成本低的优点。     

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.