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.     

Characteristics of atmospheric particles and heavy metals in winter in Chang-Zhu-Tan city clusters, China

To understand the pollution characteristics of atmospheric particles and heavy metals in winter in Chang-Zhu-Tan city clusters, China, total suspended particulate(TSP) and PM10samples were collected in cities of Changsha, Zhuzhou and Xiangtan from December 2011 to January 2012, and heavy metals of Cd, Pb, Cr, and As were analyzed. It shows that the average TSP concentration in Changsha, Zhuzhou and Xiangtan were(183 ± 73),(201 ± 84) and(190 ± 66) μg/m3respectively, and the average PM10 were(171 ± 82),(178 ± 65) and(179 ± 55) μg/m3respectively. The lowest TSP and PM10concentrations occurred at the background Shaping site of Changsha. The average ratio of ρ(PM10)/ρ(TSP) was 91.9%, ranging from 81.3% to 98.9%. Concerning heavy metals, in TSP samples, the concentration of Cr, As, Cd and Pb were 28.8–56.5, 18.1–76.3, 3.9–26.1 and 148.0–460.9 ng/m3, respectively, while in PM10samples, were 16.4–42.1, 15.5–67.9, 3.3–22.2 and 127.9–389.3 ng/m3, respectively. The enrichment factor of Cd was the highest, followed by Pb and As, while that of Cr was the lowest.     

某储罐区火灾多米诺效应场景推演

化工园区中危险源众多,一旦发生事故很容易在整个园区内蔓延和发展.针对化工园区内储罐密集,容易引发连锁反应导致事故扩大的特点,利用FDS软件对储罐火灾场景进行数值模拟,根据储罐所受热辐射确定化工园区内储罐火灾最可能的事故发生序列,并引入基于设备失效前时间的机械设备故障概率模型对罐区内单个储罐的火灾风险进行研究,得到储罐区...     

高膜通量厌氧微网生物反应器处理生活污水的研究

将动态膜技术与厌氧膜生物反应器相结合,形成一体式厌氧微网生物反应器(AnFBR),用于城市生活污水的处理,研究了在高膜通量条件下,AnFBR的运行情况和对生活污水的处理效果。结果表明,AnFBR在膜通量为72 L/(m2.h)条件下可连续稳定运行40 d;系统对COD平均去除率为58.4%,对TN和NH3-N有一定的去除效果;出水SS最高为15.0 mg/L,出水中污染物粒径在10μm以下;微网动态膜对小分子物质的截留量不高,但对分子量大于1 000 kU的物质有明显的截留效果,进水中的大部分大分子物质被转化为小分子物质;AnFBR在保留了泥水分离特点的情况下还具有结构简单、膜通量高、微网过滤周期长等优点。     

羟基铝及复合改性蒙脱石对As(V)的去除性能

采用无机羟基铝及阳离子表面活性剂十六烷基三甲基溴化铵对天然蒙脱石进行无机及复合改性。在吸附过程中研究了反应时间、投加量和pH等变量对吸附性能的影响,同时进行吸附动力学及吸附等温线研究,吸附规律符合Langmuir等温方程式。采用X射线衍射、X射线荧光、傅里叶红外光谱等表征手段对未改性及改性蒙脱石进行性能表征。研究结果表明,羟基铝及复合改性蒙脱石对As(V)具有良好的吸附性能,在pH为4～10,初始砷浓度为2 mg/L,改性蒙脱石对As(V)的去除率接近99%。吸附机理主要为羟基铝表面络合吸附和静电吸附。     

混合酶强化剩余污泥微生物燃料电池性能

为了提高剩余污泥为燃料的微生物燃料电池(SMFC)产电性能以及污泥减量化效果,在不同的温度(40、45和50℃)研究单室无膜微生物燃料电池中酶对SMFC产电特性的强化效果.加入单一酶(蛋白酶或α-淀粉酶)的结果表明,随着温度的上升,SMFC功率密度均上升,但40℃时强化效果最明显,与加入失活酶的对照组相比分别增加198％和130％.在40℃下,混合酶比(蛋白酶浓度:淀粉酶浓度)为2∶3时,SMFC最大功率密度为776 mW/m2.随着混合酶中淀粉酶的比例提高,SMFC库伦效率逐渐增加,当混合酶比为4∶1时,CE(库伦效率)可达18.3％,同时TCOD、TSS和VSS去除率分别为70.3％、66.7％和80.4％.因此,温度相对较低时,外加酶强化效果更明显;与单种酶相比,混合酶对SMFC产电性能和污泥减量化的强化效果更显著.     

上海南区污水输送干线世博期间排水安全保障

上海世界博览会将于2010年5月至10月召开,会展期跨越上海市夏季主汛期。届时如何保障世博园区的排水安全和水质安全,对接纳园区污水的已建干线排水系统是一个极大的考验。通过建立上海市南干线排水管网系统的数学水力集成模型,对世博园区污水接入后南干线的水力状态进行模拟,预测世博园区的排水风险,提出世博期间南干线的排水安全保障方案,为世博会期间的防洪保安奠定基础。     

跨海桥梁大尺度基础波浪荷载计算方法对比研究∗

波浪荷载是跨海桥梁基础的主要环境荷载之一。为了探究大尺度桥梁基础上各类波浪荷载计算方法的差异,分别采用了当前研究中较常用的Morison方程、规范、基于边界元法的三维绕射理论和基于Navier‐Stokes方程的CFD方法计算了某跨海桥梁大尺度圆端型沉井基础在规则波作用下的波浪荷载,研究了不同结构相对尺度对各方法计算结果的影响,并重点比较分析了后两种数值方法的三维流场分布,三维压力场分布,以及非线性二阶力效应的影响。结果表明,在结构相对尺度为0.2左右时,上述方法的计算结果接近,随着结构相对尺度的增加,边界元与CFD方法依然吻合较好,规范方法给出了较为保守的波浪荷载,Morison方程可能高估了波浪拖曳力的贡献。边界元与CFD方法计算得到的速度场与压力场结果整体趋势一致,但在沉井前端自由液面与物面,沉井侧面的波谷等局部区域会产生明显差异,这可能是由于二者考虑绕射效应与黏性效应的理论不同。在边界元方法中考虑非线性二阶力效应会使其波浪荷载结果小幅度增大,并在频谱中增加差频二阶力及和频二阶力成分,考虑非线性二阶力效应后,边界元与CFD方法的频谱曲线更加吻合,边界元方法能更精确地计算波浪荷载。边界元与CFD方法均能合理地给出大尺度结构物波浪荷载结果,研究结论可为跨海桥梁工程波浪荷载的准确计算提供了依据。     

A red water occurrence in drinking water distribution systems caused by changes in water source in Beijing,China: mechanism analysis and control measures

A red water phenomenon occurred in several communities few days after the change of water source in Beijing, China in 2008. In this study, the origin of this problem, the mechanism of iron release and various control measures were investigated. The results indicated that a significant increase in sulphate concentration as a result of the new water source was the cause of the red water phenomenon. The mechanism of iron release was found that the high-concentration sulphate in the new water source disrupted the stable shell of scale on the inner pipe and led to the release of iron compounds. Experiments showed that the iron release rate in the new source water within pipe section was over 11-fold higher than that occurring within the local source water. The recovery of tap water quality lasted several months despite ameliora- tive measures being implemented, including adding phosphate, reducing the overall proportion of the new water source, elevating the pH and alkalinity, and utilizing free chlorine as a disinfectant instead of chloramine. Adding phosphate was more effective and more practical than the other measures. The iron release rate was decreased after the addition of 1.5 mg. L-1 orthophosphate- P, tripolyphosphate-P and hexametaphosphate-P by 68%, 83% and 87%, respectively. Elevating the pH and alkalinity also reduced the iron release rate by 50%. However, the iron release rate did not decreased after replacing chloramine by 0.5-0.8 mg. L-1 of free chlorine as disinfectant.     

加氢装置分液罐泄漏失效原因分析

针对某石油化工公司加氢装置中变气第一分液罐底部环焊缝周围产生多处裂纹而发生泄漏的事故,通过对该压力容器使用工作环境的工况调查、设备泄漏部位裂纹宏观分析、裂纹形态及断口理化金相分析、材质化学成分检测、焊接接头金相组织分析、材料拉伸力学性能试验和硬度测试等手段,综合分析裂纹产生的原因,得出初步结论,并提出改进建议。