磁改性硅藻土对水中磷的吸附性能研究

利用硅藻土和FeSO_4·7H_2O为主要原料,采用共沉淀法制备应用于抑制水体富营养化的除磷吸附材料——磁改性硅藻土,通过BET比表面积、X射线衍射(XRD)、红外光谱(IR)和磁滞回归对其进行表征。结果表明:磁改性硅藻土表面除了含SiO_2,还增加了Fe_2O_3和Fe_2SiO_4,且具有优良的磁性;当吸附时间为120min、酸性、吸附剂投加量为10g/L时,磁改性硅藻土对磷的去除率最大,是硅藻土的4.6倍;Langmuir拟合方程能更好地拟合磁改性硅藻土对磷的等温吸附曲线,表明磁改性硅藻土对废水中磷的吸附是单分子层吸附过程;吸附饱和的磁改性硅藻土在外加磁场作用下可迅速实现固液分离。     

改性粉煤灰处理低浓度含磷废水的研究

以酸改性粉煤灰为吸附剂,处理低质量浓度(1 mg/L左右)磷酸盐溶液,探讨了改性剂的种类、改性剂用量、吸附剂用量、反应时间、pH以及温度对除磷效果的影响.结果表明:(1)经过酸改性后粉煤灰的磷去除率显著提高,而且硫酸改性粉煤灰的除磷效果更好,磷去除率最高可达97.68％.(2)最佳条件:选择硫酸用量为5 mL/g进行改性,硫酸改性粉煤灰投加量为2.0g,反应时间为60 min,pH为7.2～10.8,温度为25℃(即室温).(3)改性粉煤灰对磷的吸附更符合Freundlich吸附等温模型,既有物理吸附,也有化学吸附,并以Ca、Mg氧化物与磷形成磷的沉淀物为主.     

丙烯酰胺改性壳聚糖絮凝剂处理焦化废水

合成了丙烯酰胺改性壳聚糖絮凝剂;用该絮凝剂处理了A/O工艺处理后的焦化废水.考察了pH值、絮凝剂用量及搅拌时间对去除污染物的影响.实验结果表明,当絮凝剂用量为50.0 mg·L-1,絮凝pH值为6.5,絮凝搅拌时间为12 min,COD、F-和色度的去除率分别达到64.7%、93.2%和75%;丙烯酰胺改性壳聚糖絮凝剂对焦化废水的深度处理效果优于聚合硫酸铁和聚合氯化铝絮凝剂.     

钡盐沉积改性硅藻土的制备及其吸附Pb2+的研究

通过钡盐沉积改性制备改性硅藻土,并将其应用于吸附模拟废水中pb2+,分析了钡盐浓度、pH、改性硅藻土投加量、水样中pb2+初始浓度以及振荡时间对改性硅藻土吸附pb2+的影响,并对硅藻土的沉降性能和改性机制进行了初步的探讨.结果表明,选择0.20 mol/L钡盐改性硅藻土,在pH为7.0、投加量为2 g、水样中pb2+初...     

铝改性蒸压加气混凝土材料及其除磷效果

为进一步提高蒸压加气混凝土材料这一建材碎料的除磷效果,采用浸渍-焙烧法制备了铝改性蒸压加气混凝土碎料除磷材料(Al-MAAC),考察了Al-MAAC的最佳制备条件以及反应时间、进水磷浓度和投加量等对除磷效果的影响。研究结果表明:最佳制备条件为1 g蒸压加气混凝土粉末材料,10 mL、0.2 mol·L-1氯化铝溶液,混合改性0.5 h;当投加量为0.5 g·L-1、时间为1.5 h时,低浓度含磷废水(总磷≤1 mg·L-1)中磷的去除率可达到96.1%。综合上述结果,铝改性蒸压加气混凝土的除磷机理为材料与废水中的PO34--P反应,生成以羟基磷灰石为主的钙磷-磷铝共沉淀物,从而达到除磷目的。因此,铝改性蒸压加气混凝土可作为用于深度除磷的一种价廉易得的新型材料。     

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。     

丙烯酸废水超临界水氧化动力学研究

用H2O2作为氧化剂,对丙烯酸生产废水进行超临界水氧化研究.得到了反应速率方程表达式.COD、H2O2和水的反应级数分别为1、0和0,指前因子A为4.97 s-1,反应活化能Ea为20.64 kJ/mol,诱导时间为8 s左右.     

改性方解石的除磷能力研究

选用颗粒方解石,对其表面进行改性,便于磷在其表面的吸附、结晶、沉淀,形成永久性固态磷,加速磷的自然沉淀过程。考察了改性的最佳条件和改性方解石除磷的影响因素。结果表明,方解石的最佳改性条件:改性液TP、Ca2+、HCO-3分别为93.00、120.00、244.00 mg/L,浸泡时间2d;改性方解石具有持续的除磷能力,在实验前76h的平均除磷速率为0.053 0mg/(g·d),而稳定阶段的除磷速率为0.021 4mg/(g·d);待处理水样的Ca2+浓度对改性方解石的除磷效果有较大影响,Ca2+为120.00mg/L时除磷效果最好,碱度对除磷效果的影响很小;pH≤7.30,投加改性方解石系统中磷的去除以改性方解石表面Ca-P结晶为主,而当pH≥8.15时,溶液中发生Ca-P沉淀,而Ca-P结晶逐步减少;水温对改性方解石的除磷效果具有显著影响。     

双铝电极电絮凝处理高含氟地下水的影响因素及动力学分析

为探求电絮凝处理高含氟地下水工艺技术参数及其除氟动力学,采用双铝电极电絮凝装置处理人工模拟高含氟地下水,研究了双铝电絮凝除氟过程及其除氟动力学模型,分别考察了电流密度、pH、极板间距及初始氟浓度对电絮凝除氟过程影响。结果表明,电絮凝除氟过程符合一级反应动力学模型,理论所需除氟时间取决于初始氟浓度和除氟动力学常数,而除氟动力学常数受电流密度、极板间距和初始氟浓度影响;当电流密度为300 A·m~(-3),pH为6.0～7.0,极间距为10 mm时,双铝电絮凝除氟能效最高,氟离子去除率为89.56%,能耗为0.157 8 kWh·g~(-1);但较高的初始氟浓度容易使铝氟比下降,导致除氟效果下降,不利于除氟过程。以上结果可为电絮凝处理高含氟地下水工程化应用和除氟反应器开发提供参考。     

微絮凝-超滤工艺处理微污染水源水的中试研究

进行了微絮凝-超滤工艺处理微污染水源水的中试研究.试验结果表明:在微絮凝-超滤工艺中,相同混凝剂投加量(相同金属摩尔浓度)下铁盐比铝盐的混凝效果好;微絮凝-超滤工艺的最佳絮凝时间为120 s左右;最佳混凝剂投加量为2.2 mg/L(以Fe计).微絮凝-超滤工艺在改善出水水质和缓解膜污染方面均优于直接超滤工艺.微絮凝-超滤工艺的出水水质均符合建设部<城市供水水质标准>(CJ/T206-2005)要求.     

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.