Methods for the preparation of a biodesulfurization biocatalyst using Rhodococcus sp

Several methods to prepare a biodesulfurization (BDS) biocatalyst were investigated in this study using a strain of Rhodococcus sp. 1awq. This bacterium could selectively remove sulfur from dibenzothiophene (DBT) via the "4S" pathway. DBT, dimethylsulfoxide (DMSO), sodium sulphate and mixed sulfur sources were used to study their influence on cell density, desulfurization activity, desulfurization ability, and the cost of biocatalyst production. In contrast to that observed from bacteria cultured in DBT, only partial desulfurization activity of strain 1awq was induced by DBT after cultivation in a medium containing inorganic sulfur as the sole sulfur source. The biocatalyst, prepared from culture with mixed sulfur sources, was found to possess desulfurization activity. With DMSO as the sole sulfur source, the desulfurization activity was shown to be similar to that of bacteria incubated in medium with DBT as the sole sulfur source. The biocatalyst prepared by this method with the least cost could remove sulfur from hydrodesulfurization (HDS)-treated diesel oil efficiently, providing a total desulfurization percent of 78% and suggesting its cost-effective advantage.     

An observational study of the HONO–NO2 coupling at an urban site in Guangzhou City,South China

The temporal behavior of HONO and NO₂ was investigated at an urban site in Guangzhou city, China, by means of a DOAS system during the Pearl River Delta 2006 intensive campaign from 10 to 24 July 2006. Within the whole measurement period, unexpected high HONO mixing ratios up to 2 ppb were observed even during the day. A nocturnal maximum concentration of about 8.43 ± 0.4 ppb was detected on the night of 24 July 2006. Combining the data simultaneously observed by different instruments, the coupling of HONO–NO₂ and the possible formation sources of HONO are discussed. During the measurement period, concentration ratios of HONO to NO₂ ranged from (0.03 ± 0.1) to (0.37 ± 0.09), which is significantly higher than previously reported values (0.01–0.1). Surprisingly, in most cases a strong daytime correlation between HONO and NO₂ was found, contrary to previous observations in China. Aerosol was found to have a minor impact on HONO formation during the whole measurement period. Using a pseudo steady state approach for interpreting the nocturnal conversion of NO₂ to HONO suggests a non-negligible role of the relative humidity for the heterogeneous HONO formation from NO₂.     

荧光化学传感器的制备及其在环境分析监测中的应用

随着荧光分析技术和传感技术的发展,荧光化学传感器已经成为一种重要的连续分析测量装置.它具有很高的选择性和灵敏度,可以实现对pH、溶解氧、含氮化合物、有毒害重金属离子、有机污染物进行实时和在线测定,因此在环境分析监测方面具有广泛的应用前景.简要介绍了荧光化学传感器的原理、制备及分类,综述了近年来荧光化学传感器的发展及其在环境分析监测中的最新研究成果,并探讨了荧光化学传感器在环境分析监测领域的应用前景和发展方向.     

富营养化湖泊底泥污染控制技术评估

回顾了我国在富营养化湖泊底泥污染控制技术方面的研究进展,并从富营养化湖泊底泥污染控制技术的运用效果、环境影响、社会影响、经济性、适用性以及与其他技术的相关性等六个方面,全面评估了破坏分层、人工曝气、化学增氧、底泥疏浚和底泥封闭等五类技术.     

铝件表面处理废水治理所得化学污泥的再生利用研究

对混凝法处理铝件表面处理废水治理所得化学污泥再生利用进行了研究,得到了适宜的操作条件.结果表明,用浓硫酸溶解污泥的最佳用量为0.14～0.16 mL/g湿污泥,湿污泥的溶解率可达90%,铝的溶出率也可达95%以上.把污泥的溶解液作混凝剂回用于印染废水的混凝处理也取得了良好的效果,其COD去除率≥80%,脱色率≥90%.实现了资源的二次利用,改善了作业环境,获得了较好的经济效益和社会效益.     

生物膜填料塔SO2废气净化性能研究

采用生物膜填料塔净化SO2废气,研究结果表明:当气体流量从100L/h增加到300L/h时,SO2净化效率由86.4%下降到73.2%;生化去除量随着入口SO2气体浓度的升高而增大;随着温度的升高,SO2净化效率和生化去除量都随之提高,且20℃以上时,净化效率可达90.9%以上,生化去除量可达75 mg/L·h以上,更利于微生物降解SO2.     

Evaluation of photolysis and hydrolysis of pyraclostrobin in aqueous solutions and its degradation products in paddy water

This study evaluated the hydrolysis and photolysis kinetics of pyraclostrobin in an aqueous solution using ultra-high-performance liquid chromatography–photodiode array detection and identified the resulting metabolites of pyraclostrobin by hydrolysis and photolysis in paddy water using high-resolution mass spectrometry coupled with liquid chromatography. The effect of solution pH, metal ions and surfactants on the hydrolysis of pyraclostrobin was explored. The hydrolysis half-lives of pyraclostrobin were 23.1–115.5?days and were stable in buffer solution at pH 5.0. The degradation rate of pyraclostrobin in an aqueous solution under sunlight was slower than that under UV photolysis reaction. The half-lives of pyraclostrobin in a buffer solution at pH 5.0, 7.0, 9.0 and in paddy water were less than 12?h under the two light irradiation types. The metabolites of the two processes were identified and compared to further understand the mechanisms underlying hydrolysis and photolysis of pyraclostrobin in natural water. The extracted ions obtained from paddy water were automatically annotated by Compound Discoverer software with manual confirmation of their fragments. Two metabolites were detected and identified in the pyraclostrobin hydrolysis, whereas three metabolites were detected and identified in the photolysis in paddy water.     

堆肥中纤维素和木质素的生物降解研究现状

堆肥是垃圾处理的主要方法之一 ,厨房垃圾、园林垃圾、农村秸秆和日常生活中的废弃纤维产品均可作为堆肥原料 ,这些原料中含有一定量的纤维素和木质素 ,而纤维素和木质素在堆肥过程中较难生物降解。因此 ,国内外学者致力于研究能加速纤维素和木质素降解的高效微生物。研究发现 ,对纤维素和木质素有降解能力的微生物主要是高温放线菌和高温真菌 ,其中有独特降解机制的白腐菌在木质素降解中起着重要作用