Determination of organophosphorus pesticides and related compounds in water samples by membrane extraction and gas chromatography

A membrane extraction-gas chromatography method was developed fordetermination of organophosphorus pesticides and related compounds including methamidophos, DDVP, dimethoate, methyl parathion, parathion, thiophosphoric acid trimethyl ester, and thiophosphoramidic acid dimethyl ester in water samples. In thismethod, surface-modified acetic cellulose membranes were used to extract the target analytes in water samples, the extracted analytes were back-extracted into a small amount of methanol, andgas chromatography with pulsed flame photometric detector (GC-PFPD) was used to determine the concentrations of targetanalytes in the extracts. The recoveries obtained for thetarget analytes spiked into the water samples ranged from 66to 94%. The method detection limit for each target analyte was 0.05 g L^-1. The method developed in this study had shown the advantages of being cheap, simple, fast, and reliable. It had been used successfully to determine the concentrations of target analytes in river water samples.     

添加不同量的腐殖酸对猪粪堆肥中主要养分变化的影响

腐殖酸是一种可以控制堆肥氮素损失的天然固定剂,通过研究腐殖酸对猪粪堆肥过程中主要养分含量变化的影响,确定了腐殖酸的最佳加入量.结果表明,加入5%含量(占鲜猪粪重)的腐殖酸最有利于发酵反应的进行,能够促进有机质的分解,有效控制氮素损失,可使速效钾含量增加,但对有效磷的转化能力影响不大;与其他处理相比,加入5%含量的腐殖酸...     

Effect of wastewater composition on the calcium carbonate precipitation in upflow anaerobic sludge blanket reactors

Calcium carbonate often precipitates in anaerobic reactors treating wastewater with high calcium content. The aim of this paper is to study the effect of wastewater composition on calcium carbonate precipitation in upflow anaerobic sludge blanket (UASB) reactors. Two laboratory-scale UASB reactors were operated with calcium-containing influents using acetate and carbohydrate as substrate, respectively. There was an obvious accumulation of inorganic precipitate observed in the biogranules. Observations via scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) showed that the acclimated biogranules in the two reactors differed in microstructure. Calcium carbonate was found to have precipitated on the surface of acetate-degrading biogranules, but precipitated at the core of the carbohydrate-degrading biogranules. The results indicated that substrates had significant influence on the location of calcium carbonate precipitation in anaerobic granular sludge, which was expected due to the different methanogens distribution and pH gradient within the granular sludge degrading various substrates. Moreover, the location of calcium carbonate precipitation substantially affected the specific methanogenic activity (SMA) of the granular sludge. The SMA of the acetate-degrading biogranules dropped from $ 1.96 gCOD_{CH_4 } \cdot gVSS^{ - 1} \cdot d^{ - 1} $ 1.96 gCOD_{CH_4 } \cdot gVSS^{ - 1} \cdot d^{ - 1} to $ 0.61 gCOD_{CH_4 } \cdot gVSS^{ - 1} \cdot d^{ - 1} $ 0.61 gCOD_{CH_4 } \cdot gVSS^{ - 1} \cdot d^{ - 1} after 180-d of operation in the reactor. However, the SMA of the carbohydrate-degrading biogranules was not adversely affected by calcium carbonate precipitation.     

Synthesis of Li-doped bismuth oxide nanoplates,Co nanoparticles modification,and good photocatalytic activity toward organic pollutants

Abstract

Lithium-doped bismuth oxide nanoplates with the thickness of 50–150?nm and tetragonal bismuth oxide, monoclinic lithium bismuthate phases have been synthesized via a simple hydrothermal process using lithium acetate and sodium bismuthate as the raw materials. Cobalt nanoparticles modified lithium-doped bismuth oxide nanoplates hybrids were obtained by an in situ photo-deposition route. The cobalt nanoparticles-modified nanoplates hybrids display significantly enhanced photocatalytic activity toward gentian violet compared with the nanoplates. Gentian violet solution can be totally degraded by the hybrids within 60?min under ultraviolet–visible light irradiation. The superior photocatalytic activity of the cobalt nanoparticles modified nanoplates hybrids originates from the superior charge transfer capacity and the energy band structure of the hybrids. The excellent photocatalytic performance makes the cobalt nanoparticles modified nanoplates hybrids a promising candidate as the photocatalyst for wastewater treatment.     

南京市大气PM2.5无机组分及对A549细胞的毒性效应

为研究不同来源的大气颗粒物中PM_2.5对人体的健康毒性效应,于2016年1-3月在南京市交通源区、化工园区、生活区等代表性站点分别采集PM_2.5样品,分析其水溶性离子和金属元素含量,并以PM_2.5对人体肺上皮细胞A549染毒24 h,研究暴露于不同来源颗粒物后的细胞活性和氧化损伤程度.结果表明:交通源区和化工园区日均ρ（PM_2.5）远高于生活区,3个区域均含有大量二次污染物,其中SO₄2-、NO₃-和NH₄+占PM_2.5总离子质量的80.6%~85.0%.交通源区PM_2.5中w（Zn）较高,主要来源于燃料燃烧和柴油发动机排放;而化工园区PM_2.5中w（Cu）、w（Pb）和w（Mn）均高于其他站点.将PM_2.5染毒剂量设定为50、100、200、400 μg/mL,各站点颗粒物均显著抑制A549细胞的存活率,并呈剂量-效应关系,化工园区对细胞存活率的半抑制浓度（IC₅₀=229.1 μg/mL）最低,而在高暴露浓度（200 μg/mL）下化工园区诱导产生的活性氧（ROS）最少.因此,南京地区主要受二次污染影响,机动车污染正在加剧;化工园区的颗粒物具有较大的细胞毒性,而较低的氧化损伤程度可能与该站点颗粒物中较低的w（Zn）以及测试暴露时间有关.      

Energy consumption model and energy efficiency evaluation for CNC continuous generating grinding machine tools

Abstract

Machine tool, which is the basis energy consumed device in manufacturing system, its energy consumption model and energy efficiency evaluation are the prerequisites for energy saving in manufacturing. Considering the multi-energy-sources features，analysed the mathematical model of a CNC continuous generating grinding machine tool from the view of energy constitute. The energy sources of a CNC continuous generating grinding machine tool are classified into gear grinding system, grinding wheel dressing system and auxiliary system. Based on the power balance equations of energy flow, the energy flow system of a CNC continuous generating grinding machine tool is established. And then the energy consumption mathematical model of a CNC continuous generating grinding machine tool is set up by combining the power balance equations with the operating features of three kinds of energy sources. The case study shows that the proposed energy consumption model can provide fundamental support for energy consumption forecasting, energy efficiency analysis and energy-saving optimisation during the machine tool operation process.     

Desulphurization mechanism and engineering practice of carbide slag

Environmental Science and Pollution Research - In order to give full play to the alkaline neutralization value of carbide slag and reduce the environmental hazards of carbide slag, it is of great...     

Effect of wastewater composition on the calcium carbonate precipitation in upflow anaerobic sludge blanket reactors

Calcium carbonate often precipitates in anaerobic reactors treating wastewater with high calcium content. The aim of this paper is to study the effect of wastewater composition on calcium carbonate precipitation in upflow anaerobic sludge blanket (UASB) reactors. Two laboratory-scale UASB reactors were operated with calcium-containing influents using acetate and carbohydrate as substrate, respectively. There was an obvious accumulation of inorganic precipitate observed in the biogranules. Observations via scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) showed that the acclimated biogranules in the two reactors differed in microstructure. Calcium carbonate was found to have precipitated on the surface of acetate-degrading biogranules, but precipitated at the core of the carbohydrate-degrading biogranules. The results indicated that substrates had significant influence on the location of calcium carbonate precipitation in anaerobic granular sludge, which was expected due to the different methanogens distribution and pH gradient within the granular sludge degrading various substrates. Moreover, the location of calcium carbonate precipitation substantially affected the specific methanogenic activity (SMA) of the granular sludge. The SMA of the acetate-degrading biogranules dropped from \(1.96 gCOD_{CH_4 } \cdot gVSS^{ - 1} \cdot d^{ - 1} \) to \(0.61 gCOD_{CH_4 } \cdot gVSS^{ - 1} \cdot d^{ - 1} \) after 180-d of operation in the reactor. However, the SMA of the carbohydrate-degrading biogranules was not adversely affected by calcium carbonate precipitation.     

厦门市海水浴场泳季水质状况分析与污染防治对策

为调查厦门市海水浴场泳季水质状况,并为监测管理工作提出对策建议,根据１９９７．５－１０月对厦门市３处有代表性的沙滩海水浴场主要水质指标,如粪大肠菌群（ＦＣ）、ＤＯ、ＳＳ及石油类等的监测分析,确认ＦＣ为主要污染因子,因其含量单次测值差差异十分显著,采用数理统计方法研究其含亘的时空分布及变化,研究表明,３浴场水质状况基本符合本市潮间带功能区划的相应要求,建议加强对沙滩浴场的综合整治和陆源污水排海方式的     

SACT-B污泥快速堆肥工艺及冬季运行效果

以唐山西郊污水处理厂污泥堆肥工程为例,讲述了SACT-B污泥快速堆肥工艺的特点以及在冬季运行的效果:整个工艺过程依靠污泥处理专用设备(主要包括链条式翻堆机、固体曝气系统等非标设备)和采用定时定量曝气的方式来运行,并对污泥堆肥的效果进行评判,评判方法参考腐熟度评价系统指标中的物理性质(含水率、温度、颜色、气味等)、化学指标(挥发性固体、C/N比等)及生物指标(种子发芽率),最终评判结果证明冬季SACT-B工艺处理污泥效果良好。