Effects of relative humidity on the characterization of a photochemical smog chamber

A linear relationship between k_NO2→HONO and relative humidity in smog chamber is found in this work.     

合成腐殖酸氧化还原能力与光学性质探究

本文以合成商业腐殖酸Aldrich humic acids(AHA)与国药化学试剂腐殖酸(TJHA)为研究对象,与铁氰化钾反应测定不同浓度AHA与TJHA还原前后氧化还原能力.研究发现,原态和还原态的HA均能向铁氰化钾传递电子,还原后两种HA的氧化还原能力均大于其原态的氧化还原能力.原态和还原态TJHA的单位碳电子转移数(原态1.49 meq·g C-1;还原态20.95 meq·g C-1)均大于AHA(原态0.52 meq·g C-1;还原态1.75 meq·g C-1).同时随着HA浓度的增加,两种HA的原态与还原态单位碳电子转移数均逐渐降低(AHA:0.91—0.52 meq·g C-1;TJHA:13.57—1.49 meq·g C-1),而AHA单位体积电子转移数目逐渐增大(0.002—0.072 meq·L-1),TJHA单位体积电子转移能力无明显变化.这是由于在HA与铁氰化钾电子转移体系中,氧化还原能力的高低与腐殖酸中氧化还原官能团数量和分布有关,与HA粒径大小,分子质量也有关系.进一步通过E465,E4/E6值表明两种HA E465值与浓度呈明显正线性关系,E4/E6值与浓度呈对数增加趋势.三维荧光分析发现,HA还原后,激发/发射(Ex/Em)峰出现蓝移,相对荧光强度降低,说明HA还原的过程中有π—π*的断裂.进一步对HA荧光测定发现TJHA中具有更多数量的氧化还原官能团而AHA中氧化还原官能团种类相对丰富.     

枯草芽孢杆菌(Bacillus subtilis)过氧化氢酶的分离纯化及性质

对产自枯草芽孢杆菌Bacillus subtilis WSHDZ-01的过氧化氢酶,通过乙醇沉淀、DEAE阴离子交换层析、疏水层析3步纯化,最终获得电泳纯的目标酶(纯化6.8倍).该过氧化氢酶的亚基相对分子质量(M1)为63×103,在405 nm处显示特征吸收峰,推测含有血红素.计算获得酶的表观米氏常数为26.87 mmol L-1.该过氧化氢酶不受低亚硫酸钠的还原作用影响,但被氰化物、叠氮化物和3-氨基-1,2,4-三唑(单功能过氧化氢酶的专一抑制剂)强烈抑制.以邻苯二胺作为电子供体测定酶活时,该酶不显示过氧化物酶活性,因此本文将纯化的过氧化氢酶定性为单功能过氧化氢酶.此外,该酶具有热敏感的特点,且酶活在pH 5～10范围内不受pH影响,此后,活性随着pH的升高而升高,并在pH 11～12处有明显的酶活高峰,在pH 11、25℃放置60 min酶活基本不变,表明该酶在高碱条件下具有很高的活力和一定的稳定性.     

Multidisciplinary work on barium contamination of the karstic upper Kupa River drainage basin (Croatia and Slovenia); calling for watershed management

The present work was designed as an extension of a previous study of a barium anomaly observed in stream sediments of the Kupa River. In its upper part the Kupa River drains a region underlain by a trans-boundary aquifer. The river is a significant water resource in a region of tourism, sport, and fishing in both Croatia and Slovenia. The contamination source is situated in Homer (Lokve), Croatia, where barite was mined until 10 years ago. The barium processing waste material (<3-mm fraction) was carelessly deposited in gardens, forests, and into a sinkhole, which has an underground link with the Kupica River, a tributary of the Kupa River. Barium waste and stream sediments were analyzed using comparative techniques: X-ray diffraction (XRD), X-ray fluorescence (XRF), Mössbauer spectroscopy, and grain size analysis. XRD of the waste material identified the major minerals quartz, barite, and dolomite and the Fe-containing minor minerals muscovite and goethite. Barite was identified as a minor or trace mineral in the Kupica River sediments. XRF analysis of the waste material has shown Ba and Fe to be the predominant elements, Ca and K to be minor elements, and Mn, Zn, Sr, Pb, Co, Cu, As, Zr, Rb, Y, and Mo to be trace elements. Mössbauer spectroscopy performed at room temperature (RT) was used to study iron minerals, particularly to obtain information on the valence status of Fe ions. Grain size analysis of the waste material (<63-μm fraction) has shown that it contains 23.5% clay-size material in comparison with 7–8% clay-size material in stream sediments. It is our aim to combine geochemical and medical methods to investigate the possible impact of waste disposal on human health in Lokve. At this stage of the work, concentrations of Ba and other toxic elements in the water compartment of the Kupica River (a source of drinking water) have not been monitored by Croatian Waters (name of the Croatian water authorities). The necessity of such measurements in future studies has been highlighted. A preliminary study of diseases diagnosed in Lokve shows that about 18% of the total inhabitants have serious medical problems. Diseases of the circulatory system, endocrine, nutritional, and metabolic diseases, neoplasms, and respiratory diseases predominate. This paper calls for further multidisciplinary research on the health effects of barium and trace elements, as well as for bioremediation of contaminated gardens and for watershed management of vulnerable karstic aquifers.     

好氧颗粒污泥表征技术研究进展

随着好氧污泥颗粒化技术的兴起,好氧颗粒污泥成为研究的热点之一。各国学者对好氧颗粒污泥应用了不同的表征手段,文章对好氧颗粒污泥的物理性质表征方法、物化性质表征方法、生化性质表征方法、性能参数表征方法以及PCR、FISH、DGGE等现代分子生物学技术在好氧颗粒污泥研究中的应用进行了综述。     

培养基种类和培养条件对白腐真菌生长和产酶特性的影响

以白腐真菌(Phanerochaete chrysosporium)为研究对象,比较了该菌种在人工合成培养基和天然培养基中的生长和产酶特性,考察了竹子浸出液,pH,载体和抗生素等对白腐真菌在天然培养基中生长和产酶特性的影响.结果表明,天然培养基中白腐真菌的生物量、菌丝小球直径和木质素过氧化物酶(LiP)活性均大于人工培养基.以天然培养基为基础培养基,加入竹子浸出液可以促进白腐真菌的生长和提高木质素过氧化物酶活性;较低pH(4.5)条件下菌丝小球直径较小;载体的加入使得菌体以附着形式生长;抗生素两性霉素B对白腐真菌的生长和产酶的影响存在阈值,当ρ(两性霉素B)超过50　mg/L时,白腐真菌的生长和产酶受到明显的抑制.      

国内成功运营的餐厨垃圾处理厂臭气排放特征研究简

选择目前国内成功运营的餐厨垃圾资源化处理厂为采样点,采用气相色谱-质谱联用（GC/MS）技术对该厂的主要工段,如卸料室、破碎室、湿热反应器出气口、好氧发酵仓、厌氧发酵区以及厂界的臭气进行了定性和定量的分析。结果表明,6个采样点共检测出包括芳香烃、硫化物、卤代物、烯烃、烷烃、醇、醛、酮和酯在内的9类66种物质,各采样点臭气总浓度分别为：11.738、18.390、30.917、25.097、4.737和2.635 mg/m³。其中湿热反应器出气口处恶臭气体浓度最高,其芳香烃、硫化物、卤代物、烯烃、烷烃、酮及酯类物质均高于其他检测点,需对该工段进行重点监测和控制。恶臭排放特征分析表明,各点的H₂S浓度均超过嗅觉阈值,除厂界外甲硫醇和二甲二硫检测值均超过嗅觉阈值。     

纳米聚硅酸铝锌絮凝剂的制备及表征简

在SiO₂含量为3%,pH为3,活化时间为85 min,（Al+Zn ）/Si摩尔比为1.5,Al/Zn摩尔比为2,表面活性剂硬脂酸钠加入量为0.1%,超声频率为40 Hz,超声时间为60 min的最佳制备条件下制备出液体PSAZS絮凝剂,用超声法制成纳米级Nano-PSAZS,用环境扫描电子显微镜（ESEM）和智能型傅里叶变换红外光谱（FT-IR）等仪器进行分析。结果表明,硅有助于絮凝剂分子链的延伸,有助于生成更大分子的聚合物;铝盐和锌盐的加入到聚硅酸中,并不是简单的混合,而是发生了缩聚和配位反应,有助于生成链网状结构,能更好地发挥吸附架桥和网捕卷扫作用。同时Nano-PSAZS陈化时间为24 h时的结构有利于絮凝效果的发挥。     

DNAPL distribution in the source zone: effect of soil structure and uncertainty reduction with increased sampling density

This paper focuses on parameters describing the distribution of dense nonaqueous phase liquid (DNAPL) contaminants and investigates the variability of these parameters that results from soil heterogeneity. In addition, it quantifies the uncertainty reduction that can be achieved with increased density of soil sampling. Numerical simulations of DNAPL releases were performed using stochastic realizations of hydraulic conductivity fields generated with the same geostatistical parameters and conditioning data at two sampling densities, thus generating two simulation ensembles of low and high density (three-fold increase) of soil sampling. The results showed that DNAPL plumes in aquifers identical in a statistical sense exhibit qualitatively different patterns, ranging from compact to finger-like. The corresponding quantitative differences were expressed by defining several alternative measures that describe the DNAPL plume and computing these measures for each simulation of the two ensembles. The uncertainty in the plume features under study was affected to different degrees by the variability of the soil, with coefficients of variation ranging from about 20% to 90%, for the low-density sampling. Meanwhile, the increased soil sampling frequency resulted in reductions of uncertainty varying from 7% to 69%, for low- and high-uncertainty variables, respectively. In view of the varying uncertainty in the characteristics of a DNAPL plume, remedial designs that require estimates of the less uncertain features of the plume may be preferred over others that need a more detailed characterization of the source zone architecture.     

Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.