烟草工业废弃物中提取氨基酸

以生产烟碱及茄尼醇后的烟叶废渣为原料,采用酸水解及活性炭脱色处理提取氨基酸,研究了酸水解中HCl用量、水解时间以及活性炭脱色处理中活性炭处理方式、pH、活性炭用量、脱色温度和脱色时间等因素对氨基酸收率和脱色率的影响。结果表明,最佳水解条件:以6 mol/L HCl溶液为水解液,在120℃、料液比1∶18条件下,水解12 h,所得水解液经以下工艺脱色处理:0.25%KOH处理活性炭、pH=10、活性炭用量为2.5%、脱色温度80℃、脱色40 min,所得产物氨基酸收率86.65%,脱色率达84.31%。     

2种处理方法水解剩余污泥蛋白质的研究

运用了木瓜蛋白酶、超声波和蛋白酶联合使用的2种处理方法水解剩余污泥蛋白，以水解液中蛋白质提取率为指标，分析了2种水解处理方法对剩余污泥处理效果的影响。蛋白酶水解提取法的最佳条件是：反应体系木瓜蛋白酶的浓度为6％，固液比为1：4，水解温度为55℃，水解时间为5．5h；蛋白质的提取率为51．71％。超声波和蛋白酶联合的最佳条件是：P=30W，T=45min，蛋白质的提取率为66．60％。结果表明，超声波和蛋白酶联合使用的水解方法优于蛋白酶水解。     

二次纤维稀酸水解糖化的研究

研究了稀酸作用下二次纤维的水解糖化,探讨了水解各因素温度、H2SO4浓度、时间、液固比以及不同酸、催化剂对水解效果的影响。实验结果表明,在H2SO4作用下最佳工艺为:H2SO4质量分数4%,水解温度190℃,水解时间40min,液固比15(mL/g);还原糖得率为33.26%,水解率为56.83%。不同稀酸对OCC的水解,HCl比H2 SO4、H3 PO4、HNO3具有明显的优势;催化剂FeSO4与CuSO4对还原糖得率有显著的促进作用,还原糖得率分别提高了39.66%与22.03%,而Al2(SO4)3对OCC水解没有促进作用。最后,对不同水解时间后的OCC残渣的红外结晶指数以及基团结构变化进行了分析,分析结果与实验结果相一致。     

循环流化床灰制备聚合氯化铝铁絮凝剂

以煤矸石电厂循环流化床灰(CFB灰)为原料,采用酸浸、水解、聚合和熟化等工艺过程,制备聚合氯化铝铁(PAFC)絮凝剂产品。重点对制备PAFC絮凝剂的酸浸工艺参数进行研究,其最佳工艺条件为:盐酸浓度为20.2%、酸浸温度为110℃、酸浸时间为2 h、液固比为4∶1;Fe2O3浸出率为90.6%,Al2O3的浸出率为48.5%。同时采用实验得出的最优工艺参数进行了产品制备,并对产品进行了絮凝性能实验。结果表明,在相同条件下PAFC的絮凝效果明显好于聚合氯化铝(PAC),用CFB灰制备PAFC絮凝剂产品是可行的。     

微波联合酸预处理对厨余垃圾酶水解糖化的影响

酶水解糖化是厨余垃圾制造燃料乙醇的关键步骤,对厨余垃圾进行预处理以促进糖化过程,具有重要意义.以学生食堂厨余垃圾为原料,以常规、微波为加热手段,比较不同预处理方式对厨余垃圾酶水解的影响.结果表明,微波加热结合酸性溶剂的预处理方式最有利于厨余垃圾酶水解糖化.考察微波联合酸预处理的影响因素,得到最佳的预处理条件为:溶剂为H2SO4、溶剂浓度3％、微波功率80 W,预处理时间40 min,固液比1∶8,该条件预处理后,与未经预处理的厨余垃圾酶水解糖产量相比,提高46.1％.     

稻草经超声波辅助预处理后酶解过程的动力学研究

在功率为120 W、处理时间为30 min的条件下,分别对稻草进行超声波辅助酸碱预处理,与传统化学预处理(碱-预处理、酸-预处理)后稻草的主要化学组成相比较,结果表明超声波技术辅助酸碱预处理可以更为有效地去除半纤维素和木质素,从而提高了稻草基质中纤维素的相对含量,有利于缩短稻草水解时间。在一系列实验研究的基础上,建立了稻草酶水解动力学模型。结果表明,分别经碱、超声波-碱、酸、超声波-酸预处理的稻草在糖化过程中的模型参数(米氏常数KM,速率常数k和抑制常数KI)均不相同,KM分别为17.55、14.14、15.29和15.08 g/L;k分别为15.30、21.32、13.40和15.42 h-1;抑制常数KI变化不明显分别为2.31、2.08、1.81和1.85 g/L。模型及实验方法简便可靠,有较好的拟合性,对稻草酶水解过程工程放大及过程控制都具有一定的参考价值。     

用钛白废酸和副产锌泥制备活性氧化锌

以次硫酸氢钠甲醛副产锌泥和钛白废酸为原料,经高剪切乳化、酸浸、锌粉置换、除杂、碱锌合成等工艺制得碱式碳酸锌,再经过滤、洗涤、干燥、煅烧制备活性氧化锌。考察了浸取工艺液固比(硫酸与副产锌泥的质量比)和硫酸质量分数对锌浸出率的影响,以及煅烧温度和时间对活性氧化锌质量的影响。实验结果表明,锌泥酸浸工艺的最佳液固比4,硫酸质量分数30%,在此工艺条件下,锌浸出率达95%。活性氧化锌的最佳煅烧温度为600℃,煅烧时间为240 min,在此条件下测定产品质量,氧化锌质量分数大于96%,比表面积大于50 m2/g,堆积密度小于0.35 g/m L。     

初沉污泥球磨破解后水解酸化研究

采用球磨机对污水处理厂初沉池的污泥进行球磨破解以控制初沉污泥粒径,然后在不同条件下(污泥粒径、系统pH、污泥投配率)考察初沉污泥的水解酸化效果(以溶解性COD(SCOD)变化显示),以确定初沉污泥水解酸化的最佳条件。结果表明,初沉污泥的最佳水解酸化条件为:污泥粒径25μm、系统pH 11、污泥投配率10%、水解酸化时间5d,此时反应后系统SCOD为8 256mg/L,污泥水解转化效率为32.0%。通过球磨破解、水解酸化的方式回收初沉污泥中的碳源具有一定的可行性和较好的开发利用前景。采用球磨机作为污水处理厂初沉污泥预处理的装置,与其他方法如超声波法、热处理法等相比较,具有适应力强、操作可靠、运行简单等优点。     

超声破解与发酵温度对剩余污泥产酸与组成的影响

利用超声波对剩余污泥进行破解预处理,可以提高水解酸化产酸量与产酸速率,发酵温度是另一个影响水解酸化过程的因素。研究了弱超声(0.48 k W·L~(-1),5 min)、强超声(0.96 k W·L~(-1),15 min)预处理以及发酵温度(25、37和55℃)对水解酸化产酸量与产酸速率影响,并分析了挥发性脂肪酸(VFA)各组分浓度。研究表明,中温下进行水解酸化,超声预处理后产酸量较未处理时有明显增加。各发酵温度下,弱超声(0.48 k W·L~(-1),5 min)预处理与未处理相比,产酸速率相差不大,高温下进行水解酸化,各组VFA产量、产酸速率均较常温与中温条件下水解酸化有显著增加。此时,超声波预处理的作用不再明显,发酵温度成为影响VFA产量与产酸速率的主要因素。发酵过程中产生的VFA以乙酸为主。中温条件下各组乙酸百分含量均高于常温和高温条件。并且强超声破解会促进常温和中温酸化过程中2个C以上的有机酸产生,对高温条件该规律不再适用。     

养殖固体废物在硝酸和磷酸溶液中的水解特性

养殖固体废物掺杂磷肥工艺中养殖固体废物与酸的反应直接影响其有机组成。以鸡粪为研究对象,采用L16(45)正交试验研究了鸡粪粒径、酸浓度、鸡粪与酸溶液质量比、反应温度和反应时间对鸡粪在硝酸和磷酸溶液中水解过程的影响。结果表明,硝酸溶液中影响因素显著性依次为鸡粪与硝酸质量比、反应时间、硝酸浓度、鸡粪粒径、反应温度,最优工艺条件为鸡粪粒径0.20mm、硝酸质量分数15%、鸡粪与硝酸质量比0.2∶1.0、反应温度95℃、反应时间4h;在磷酸溶液中影响因素显著性依次为鸡粪与磷酸质量比、反应温度、鸡粪粒径、磷酸浓度、反应时间,鸡粪水解率与反应温度间呈正相关关系,最优工艺条件为鸡粪粒径0.40mm、磷酸质量分数60%、鸡粪与磷酸质量比0.1∶1.0、反应温度95℃、反应时间8h。鸡粪比表面积及其单位质量耗酸量、美拉德反应是制约鸡粪在硝酸和磷酸中水解反应的内因。研究结果为养殖固体废物掺杂有机磷肥的研发和推广提供了理论基础。     

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.     

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.     

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.     

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 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.     

Knowledge transfer initiative between molecular biologists and environmental researchers and regulators

A Natural Environment Research Council (NERC) funded Knowledge Transfer (KT) workshop was held in the United Kingdom (UK) to identify the needs and opportunities in the application of molecular biology and ‘omics’ techniques to environmental monitoring and risk assessment. Attendees highlighted a lack of effective communication between end-users and researchers as well as difficulties with data interpretation as reasons behind the slow uptake of molecular biology and omics techniques. A number of promising areas in which new techniques could be implemented at a practical level in the very near future were identified, thereby raising the profile of these recent technologies and providing vital proof of concept work. Molecular taxonomy, bacterial source tracking and pre-screening of chemicals for potential toxicities were all viewed as areas in which omics and molecular techniques could have immediate value, with the aim of reducing cost, increasing efficiency and providing more comprehensive data of improved quality.     

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.