Heterogeneous Fenton-like degradation of 4-chlorophenol using iron/ordered mesoporous carbon catalyst

Ordered mesoporous carbon supported iron catalysts(Fe/OMC) were prepared by the incipient wetness impregnation method and investigated in Fenton-like degradation of 4-chlorophenol(4CP) in this work. XRD and TEM characterization showed that the iron oxides were well dispersed on the OMC support and grew bigger with the increasing calcination temperature. The catalyst prepared with a lower calcination temperature showed higher decomposition efficiency towards 4CP and H2O2, but more metals were leached. The effect of different operational parameters such as initial pH, H2O2 dosage, and reaction temperature on the catalytic activity was evaluated. The results showed that 96.1% of 4CP and 47.4% of TOC was removed after 270 min at 30°C, initial pH of 3 and 6.6 mmol/L H2O2. 88% of 4CP removal efficiency was retained after three successive runs, indicating Fe/OMC a stable catalyst for Fenton reaction. 4CP was degraded predominately by the attack of hydroxyl radical formed on the catalyst surface and in the bulk solution due to iron leaching. Based on the degradation intermediates detected by high performance liquid chromatography, possible oxidation pathways were proposed during the 4CP degradation.     

Combination of heterogeneous Fenton-like reaction and photocatalysis using Co-TiO2 nanocatalyst for activation of KHSO5 with visible light irradiation at ambient conditions

A novel coupled system using Co–Ti O2 was successfully designed which combined two different heterogeneous advanced oxidation processes, sulfate radical based Fenton-like reaction（SR-Fenton） and visible light photocatalysis（Vis-Photo）, for degradation of organic contaminants. The synergistic effect of SR-Fenton and Vis-Photo was observed through comparative tests of 50 mg/L Rhodamine B（Rh B） degradation and TOC removal. The Rhodamine B degradation rate and TOC removal were 100% and 68.1% using the SR-Fenton/Vis-Photo combined process under ambient conditions, respectively. Moreover, based on XRD, XPS and UV-DRS characterization, it can be deduced that tricobalt tetroxide located on the surface of the catalyst is the SR-Fenton active site, and cobalt ion implanted in the Ti O2 lattice is the reason for the visible light photocatalytic activity of Co–Ti O2. Finally, the effects of the calcination temperature and cobalt concentration on the synergistic performance were also investigated and a possible mechanism for the synergistic system was proposed. This coupled system exhibited excellent catalytic stability and reusability,and almost no dissolution of Co2＋was found.     

三维花状结构α-FeOOH协同H2O2可见光催化降解双氯芬酸钠

采用油浴回流法,在常压回流反应条件下批量制备出三维花状结构的α-Fe OOH纳米材料,并利用XRD、FT-IR和SEM等仪器对其进行分析表征;以双氯芬酸钠为目标污染物,考察三维花状结构α-Fe OOH纳米材料,在模拟太阳光照射下,催化H2O2降解有机污染物的性能.结果表明,三维花状结构α-Fe OOH由纳米棒自组装形成,纳米棒的长度约400~500 nm,直径约40~60 nm.以模拟可见光为光源,三维花状结构α-Fe OOH与H2O2构成光助异相类Fenton体系,对双氯芬酸钠有良好的光催化降解效果,在90 min内对初始浓度为30 mg·L-1的双氯芬酸钠降解去除率达到99%以上,催化降解反应以羟基自由基氧化反应为主.     

新农药硫肟醚在土壤中降解的影响因子研究

在实验室条件下对新农药硫肟醚(O(3苯氧苄基)2甲硫基1(4氯苯基)丙基酮肟醚)在土壤中降解的影响因子进行了研究.结果表明,在20 d的培养时间内,随着土壤含水量的增加,硫肟醚的降解速率加快.当土壤含水量增加到80%(质量分数)时,其降解率达到最大(46.73%),然后随土壤含水量增加反而下降.随着土壤温度的升高,硫肟醚在土壤中的降解速率增加.30 ℃时降解速率达到最大(47.83%),以后温度继续升高,其降解速率呈现出下降趋势.在5～100 mg/kg的质量比范围内硫肟醚在土壤中的降解速率随其质量比的增加而提高;但当质量比继续增加时,硫肟醚的降解速率表现出下降趋势.硫肟醚在土壤中的降解遵循一级动力学方程,其在非灭菌与灭菌土壤中的降解速率常数k分别为8.106×10-3和1.63×10-3;半衰期分别为85.5 d和425.2 d.微生物对硫肟醚在土壤中的降解具有显著的影响.     

北京官厅水库中农药类内分泌干扰物分布和来源

研究了北京官厅水库中农药类内分泌干扰物污染水平、分布特点和来源.结果表明,官厅水库及其支流水体受到农药类内分泌干扰物轻度污染.从农药在官厅水库中的分布推断,官厅水库以及各支流周边地区及农田排水渠是水库中农药的重要来源.底泥中农药通过底泥孔隙向表面水扩散,是表面水农药的1个污染源.由于水库周边较多的农业活动,可能导致水中农药浓度提高.为了减少污染和水生生物对内分泌干扰物的暴露,需要进行定期监测,减少农药的使用和农事操作.     

铜渣催化H2O2氧化处理棉浆黑液

采用铜渣催化H2O2类Fenton氧化反应处理棉浆黑液,研究了酸析pH、H2O2投加量、铜渣投加量对棉浆黑液COD和TOC去除率及溶出Fe2+质量浓度的影响,考察了铜渣重复使用性能,讨论了铜渣催化作用机制.结果表明:在酸析pH为2、H2O2投加量为25 mmol/L、铜渣投加量为2.5 g/L条件下,反应180 min...     

蔬菜污染:这个杀手有点冷

蔬菜,我们生活中不可或缺的食物,每个人每天都要品味蔬菜的甘甜,摄取蔬菜的营养。然而,不知从何时起,老百姓开始抱怨,这个菜不能吃,那个菜吃了对身体有害,逛一圈菜市场,篮子仍空空如也,不知道买什么好。说起来或许有点夸张,但在餐桌上,蔬菜污染这个平日隐形的杀手早已现身……     

学校灾情评估研究综述

目前我国学校防灾减灾存在许多薄弱环节,安全教育缺乏长效机制,灾情评估缺少科学指导。本文明确了学校灾情评估的必要性,并从国内外学校防灾减灾和灾情评估的相关理论、案例研究入手分析,得出我国学校灾情评估技术环节需要更新,评价体系需要创新的结论。     

小“菜”一碟

<正>编者按:眼下,虚拟世界里的"偷菜"游戏正风靡神州,无数国人沉湎其中,争分夺秒、不分昼夜,为的就是一个新鲜有趣;而在现实生活中,也有无数主妇(夫)为"买菜"、"挑菜"而大费脑筋,为的就是味道可口,食品安全。     

毛细管柱气相色谱法测定大气污染源氯苯类化合物

建立了毛细管柱-ECD检测器气相色谱测定大气污染源中氯苯类污染物的检测方法,当采样量为30 L时,方法检测限：氯苯0.03μg/m^3、1.2-二氯苯0.10μg/m^3、1.4-二氯苯0.08μg/m^3、1.2.4-三氯苯0.20μg/m^3,加标回收率在78.9%-90.6%之间,相对标准偏差为2.7%-3.3%。方法简单、灵敏、分离度好、检出限低。