Interfacial effects of suspended particles on biodegradation of N (2,4 dimethyl phenyl) N'' methylformamidine hydrochloride and dibutyl phthalate in waters

ＩｎｔｅｒｆａｃｉａｌｅｆｅｃｔｓｏｆｓｕｓｐｅｎｄｅｄｐａｒｔｉｃｌｅｓｏｎｂｉｏｄｅｇｒａｄａｔｉｏｎｏｆＮ（２，４ｄｉｍｅｔｈｙｌｐｈｅｎｙｌ）Ｎ’ｍｅｔｈｙｌｆｏｒｍａｍｉｄｉｎｅｈｙｄｒｏｃｈｌｏｒｉｄｅａｎｄｄｉｂｕｔｙｌｐｈｔｈ...     

典型北方高碱度微污染水体强化混凝的示范研究

以高碱度、受有机物污染的典型北方水体为例,探索适宜的强化混凝技术.在水质调查的基础上,提出适合水质特征的强化混凝目标.研究了高碱度水体强化混凝技术方法.研究表明,可以通过3条技术途径提高水体中有机物的去除效率.其一在混凝前优化pH,促进絮凝剂水解形成中聚体,AlCl3在pH 6左右,FeCl3在pH 5左右时,有机物去除率可以提高一倍左右;其二是强化沉淀软化;其三是絮凝剂优化.结合我国实际情况,通过对传统絮凝剂进行改性,研制出了适合我国北方水质特征的高效絮凝剂,能较传统絮凝剂将有机物去除率提高30%以上.     

南京北郊冬夏季大气PM2.5中水溶性有机碳的研究

为研究南京北郊大气PM_(2.5)中水溶性有机碳(WSOC)的浓度及来源特点,在冬、夏季分别采集PM_(2.5)样品,还同步收集臭氧(O_3)浓度与相对湿度(RH)数据,分析了PM_(2.5)、有机碳(OC)、水溶性有机碳(WSOC)浓度特征,并对WSOC冬、夏季来源及其二次来源差异进行了探讨.结果显示,南京北郊冬季大气污染水平明显高于夏季且来源更复杂,与冬季静稳的天气条件及化石燃料和生物质燃烧排放较严重有关.冬季PM_(2.5)平均值为(136.7±42.4)μg·m~(-3),OC、WSOC浓度分别为(13.4±4.4)、(8.5±3.1)μg·m~(-3);夏季PM_(2.5)、OC、WSOC平均浓度分别为(61.5±14.6)、(6.7±2.1)、(4.6±1.7)μg·m~(-3).冬、夏季WSOC/OC值分别为67%±20%、69%±13%,且二次有机碳(SOC)与WSOC显著正相关,说明二次来源对WSOC有显著影响.冬季WSOC与O_3的负相关性不显著,与RH显著正相关;而夏季WSOC与O_3、RH的相关性正好与冬季相反,说明冬、夏季二次WSOC形成途径存在差异.冬季二次WSOC可能主要来自液相氧化,夏季可能主要来自光化学氧化.通过主成分因子分析法进一步确定南京北郊冬、夏季WSOC分别主要来源于二次来源和生物质燃烧、汽车尾气和扬尘.     

Simultaneous determination of dissolved organic nitrogen, nitrite, nitrate and ammonia using size exclusion chromatography coupled with nitrogen detector

Accurate quantification of dissolved organic nitrogen (DON) has been a challenge due to the cumulative analytical errors in the conventional method via subtracting dissolved inorganic nitrogen species (DIN) from total dissolved nitrogen (TDN). Size exclusion chromatography coupled with an organic nitrogen detector (SEC-OND) has been developed as a direct method for quantification and characterization of DON. However, the applications of SEC-OND method still subject to poor separations between DON and DIN species and unsatisfied N recoveries of macromolecules. In this study, we packed a series of SEC columns with different lengths and resin materials for separation of different N species and designed an independent vacuum ultraviolet (VUV) oxidation device for complete oxidation converting N species to nitrate. To guarantee sufficient N recoveries, the operation conditions were optimized as oxidation time ≥ 30 min, injection mass (sample concentration × injection volume) < 1000 µL × mg-N/L for macromolecular proteins, and neutral pH mobile eluent. The dissolved O₂ concentration in SEC mobile phase determined the upper limit of VUV oxidation at a specific oxidation time. Compared to conventional HW50S column (20 × 250 mm), HW40S column (20 × 350 mm) with mobile phase comprising of 1.5 g/L Na₂HPO₄·2H₂O + 2.5 g/L KH₂PO₄ (pH = 6.85) could achieve a better separation of DON, nitrite, nitrate, and ammonia. When applied to river water, lake water, wastewater effluent, groundwater, and landfill leachate, the SEC-OND method could quantify DON as well as DIN species accurately and conveniently even the DIN/TDN ratio reached 0.98.     

Insights into reactive oxygen species formation induced by water-soluble organic compounds and transition metals using spectroscopic method

Ambient particulate matter (PM) can cause adverse health effects via their ability to produce Reactive Oxygen Species (ROS). Water-Soluble Organic Compounds (WSOCs), a complex mixture of organic compounds which usually coexist with Transition Metals (TMs) in PM, have been found to contribute to ROS formation. However, the interaction between WSOCs and TMs and its effect on ROS generation are still unknown. In this study, we examined the ROS concentrations of V, Zn, Suwannee River Fulvic Acid (SRFA), Suwannee River Humic Acid (SRHA) and the mixtures of V/Zn and SRFA/SRHA by using a cell-free 2′,7′-Dichlorodihydrofluorescein (DCFH) assay. The results showed that V or Zn synergistically promoted ROS generated by SRFA, but had an antagonistic effect on ROS generated by SRHA. Fluorescence quenching experiments indicated that V and Zn were more prone to form stable complexes with aromatic humic acid-like component (C1) and fulvic acid-like component (C3) in SRFA and SRHA. Results suggested that the underlying mechanism involving the fulvic acid-like component in SRFA more tending to complex with TMs to facilitate ROS generation through π electron transfer. Our work showed that the complexing ability and complexing stability of atmospheric PM organics with metals could significantly affect ROS generation. It is recommended that the research deploying multiple analytical methods to quantify the impact of PM components on public health and environment is needed in the future.     

对厌氧消化中硫化氢毒性控制的探讨

在厌氧消化处理高浓度硫酸盐废水时，不但存在硫酸盐还原菌与产甲烷菌之间发生基质竞争的问题，而且硫酸盐还原菌将硫酸盐还原产生的硫化氢对产甲烷菌产生毒性作用。本文介绍硫化氢对产甲烷菌产生毒性作用的动力学方程，详细分析在厌氧消化条件下硫化氢对产甲烷菌产生毒性作用的机理，重点阐述三种控制硫化氢毒性的方法：气体吹脱法、化学沉淀法和生物除硫法。     

小型硫磺回收装置的设计与试运

介绍寒冷地区小型硫磺回收的设计特点，包括选用一、二、三级冷凝器同壳、低噪音鼓风机；试生产中的改进经验，包括过程气用蒸汽夹套保温，带有硫封的被硫储罐．     

光化学反应的环境效应

光化学反应具有良好的环境效应，本文概述了有机合成和环境化学中光化学反应对环境的影响。     

利用工农业有机废弃物生产优质无土栽培基质

简述了无土固体基质的发展史及趋势,综述了利用工农业有机废弃物生产无土栽培基质的研究、开发和应用的现状。根据无土栽培基质的一般要求对利用工农业有机废弃物生产无土栽培基质应注意的问题进行了讨论,提出采用新技术、新工艺进行标准化生产是发展这一具有广阔前景产业的关键。