Decomplexation of Cu-1-hydroxyethylidene-1,1-diphosphonic acid by a three-dimensional electrolysis system with activated biochar as particle electrodes

The feasibility of decomplexation removal of typical contaminants in electroplating wastewater, complexed Cu(II) with 1-hydroxyethylidene-1,1-diphosphonic acid (Cu-HEDP), was first performed by a three-dimensional electric reactor with activated biochar as particle electrodes. For the case of 50 mg/L Cu-HEDP, Cu(II) removal (90.7%) and PO initial pH 7, acid-treated almond shell biochar (AASB) addition 20 g/L, and reaction time 180 min, with second-order rate constants of 1.10 × 10⁻³ and 1.94 × 10⁻⁵ min⁻¹respectively. The growing chelating effect between Cu(II) and HEDP and the comprehensive actions of adsorptive accumulation, direct and indirect oxidation given by particle electrodes accounted for the enhanced removal of Cu-HEDP, even though the mineralization of HEDP was mainly dependent on anode oxidation. The performance attenuation of AASB particle electrodes was ascribed to the excessive consumption of oxygen-containing functionalities during the reaction, especially acidic carboxylic groups and quinones on particle electrodes, which decreased from 446.74 to 291.48 µmol/g, and 377.55 to 247.71 µmol/g, respectively. Based on the determination of adsorption behavior and indirect electrochemical oxidation mediated by in situ electrogenerated H₂O₂ and reactive oxygen species (e.g., •OH), a possible removal mechanism of Cu-HEDP by three-dimensional electrolysis was further proposed.     

废水中优先控制污染酚的HPLC分离-电化学检测

研究了 HPL C分离 -安培法检测四种优先控制污染酚的色谱条件。在 Shim- pack CL C- ODS柱上 ,以 0 .1mol/L Na H2 PO4 +0 .0 5 mm ol/L EDTA· 2 Na+1% CH3 COOH(p H3.0 ) +5 0 % CH3 OH作流动相 ,氧化电位 +1.0 V检测。工作曲线的线性范围在 0～ 30μg/ml,检测限达 ng/m l     

阳极材料对医院污水电化学消毒处理效果的研究

分析了三维电极法处理医院污水的影响因素，探讨了阳极材料、电流密度．水力停留时间、空气流量、极水比等因素对消毒效果的影响，确定在不加化学药剂、不影响水质和低耗能条件下电化学消毒试验的最佳使用条件。结果表明，在用涂有贵金属（钌、铂、铱）氧化物的钛板作阳极，不锈钢板作阴极，电流密度为6mA／cm^2、水力停留时间为15min、空气流量为40L／h、极水比为1．0的试验条件下，消毒后污水中总大肠菌群数〈500CFU／L。电化学法消毒处理医院污水方法简单有效、运行费用低，无二次污染．处理后的污水达到国家一级排放标准（GB8978—1996）。     

高压脉冲电凝聚技术处理活性染料废水试验研究

难生物降解有机废水是废水处理的难点。阐述了高压脉冲电凝聚技术处理高浓度、难生物降解有机废水的最新机理。采用高压脉冲电凝聚技术处理活性染料（活性红）生产废水．研究了影响高压脉冲电凝聚技术处理活性染料废水效果的操作条件及影响因素．结果表明，在最佳处理工艺条件下。CODCr浓度12628mg／L的生产废水经处理后CODCr去除率为65％左右。再经后续混凝沉淀，最终出水CODCr可降低到1000mg／L以下。     

Investigation of titanium liquid/gas diffusion layers in proton exchange membrane electrolyzer cells

In a proton exchange membrane electrolyzer cell (PEMEC), liquid/gas diffusion layer (LGDL) is expected to transport electrons, heat, and reactants/products to and from the catalyst layer with minimum voltage, current, thermal, interfacial, and fluidic losses. In addition, carbon materials, which are typically used in PEM fuel cells (PEMFCs), are unsuitable in PEMECs due to the high ohmic potential and highly oxidative environment of the oxygen electrode. In this study, a set of titanium gas diffusion layers with different thicknesses and porosities are designed and examined coupled with the development of a robust titanium bipolar plate. It has been found that the performance of electrolyzer improves along with a decrease in thickness or porosity of the anode LGDL of titanium woven meshes. The ohmic resistance of anode LGDL and contact resistance between anode LGDL and the anode catalyst play dominant roles in electrolyzer performance, and better performance can be obtained by reducing ohmic resistance. Thin titanium LGDLs with straight-through pores and optimal pore morphologies are recommended for the future developments of low-cost LGDLs with minimum ohmic/transport losses.     

基于单片机的低成本硫化氢监测系统设计

设计了一款基于单片机AT89S52的低成本硫化氢监测报警系统,介绍了该系统的工作原理和设计方法。硫化氢气体浓度由电化学气体传感器ME4-H2S采集,电流信号经I/V转换后送单片机处理并通过LCD显示当前浓度,通过与设定标准浓度进行比较,继而判断是否发出报警。仿真测试表明,该系统结构简单,工作可靠,指示灯颜色显示三级不同警报,可以应用于高温沙漠、下水道、石油天然气钻井作业等恶劣气候、恶劣环境场合。     

地表水环境监测进展与问题分析

地表水环境的质量监测对我国水环境保护工作具有非常重要的作用,同时对我国的经济发展有着深远的影响。随着我国经济的快速发展,我国水环境监测工作有了较大的发展,但是在仪器更新、分析能力等方面还存在一系列的问题,本文对地表水环境监测的进展进行了阐述,并分析了水环境监测中存在的问题。     

火电厂煤尘污染防治主要措施研究

文章通过对火电项目煤尘产生源的分析,根据北方地区社会、经济、环境现状,提出电厂储煤场及输煤系统煤尘的主要防治措施,从而为北方经济欠发达地区火电厂的煤尘污染防治提供一些参考依据,促进环境质量的改善。     

Safety testing of pesticides and methods of evaluating human exposure in the field

Abstract

The importance of field surveys to provide data on acute pesticide hazards is discussed. The types of questions which small field surveys of pesticide exposure should answer are presented. In addition to protective clothing, the value of distance, time, and personal hygiene in reducing exposure are considered. Finally, the importance of an adequate data base for the development of protocols and guidelines for public protection is discussed.     

青龙县“四荒“治理开发的几点做法

青龙满族自治县被列为河北省桃林口水库上游重点治理区,境内大量“四荒”资源闲置浪费。该县立足县情,制定优惠政策,强化管理,因地制宜地开发这些资源,取得显著成效,其做法值得推广和借鉴。