Removal of bentazone from micro-polluted water using MIEX resin: Kinetics, equilibrium, and mechanism

The contamination of surface and ground water by bentazone has attracted increasing global concern in recent years. We conducted a detailed investigation using MIEX resin to eliminate bentazone from waters. Batch experiments were carried out to evaluate the e ect of process parameters, such as retention time, resin amount, and initial pesticide concentration, on removal e ciency of bentazone. Results showed the sorption process was fast and bentazone could be e ciently removed in 30 minutes. The kinetic process of bentazone sorption on MIEX resin was well described by pseudo second-order model and intraparticle di usion was the rate controlling step. The MIEX resin possessed the highest sorption capacity of 0.2656 mmol/mL for bentazone according to Langmuir fitting. Bentazone is a hydrophobic ionizable organic compound, and both ionic charge and hydrophobic aromatic structure governed the sorption characteristics on MIEX resin. The di erent removal e ciencies of ionic and non-ionic pesticides, combined with the charge balance equations of bentazone, SO4 2??, NO3?? and Cl??, indicated that removal of bentazone using MIEX resin occurred primarily via ion exchange.     

国家环境数据共享与服务体系研究

结合我国环境数据共享与服务面临的问题,对国家环境数据共享与服务体系的时代背景、概念和实质、技术框架、主要建设内容等进行了研究。指出国家环境数据共享与服务体系是政府主导建设的环境信息资源网,核心由三级环境数据中心、依托于四级专网的环境数据传输与交换平台以及分别依托于内网、专网和互联网的各级共享服务门户构成。     

污泥流化床干化器换热器盘管磨损现象分析和对策

污泥干化焚烧是大中城市污泥处理处置中的一个重要环节,以石洞口污泥干化焚烧为例,由于污泥中含有一定量的细沙,在脱水污泥与流化床换热器内盘管进行热交换和干化过程中,污泥不可避免地对换热器盘管产生摩擦,如何减小污泥干化过程中对换热器的磨损,延长流化床干燥器使用寿命和提高污泥干化处理能力是国内流化床干化污泥工艺必须解决的一个重要问题。本文根据长期对流化床运行工艺的理解和现场观测,从不同方面提出延长干燥器使用周期的方法和方案,有助于国内相似设备在运行中借鉴。     

Selection of magnetic anion exchange resins for the removal of dissolved organic and inorganic matters

Four magnetic anion exchange resins (MAERs) were used as adsorbents to purify drinking water. The effect of water quality (pH, temperature, ionic strength, etc.) on the performance of MAER for the removal of dissolved organic matter (DOM) was also investigated. Among the four studied MAERs, the strong base resin named NDMP-1 with high water content and enhanced exchange capacity exhibited the highest removal rate of dissolved organic carbon (DOC) (48.9% removal rate) and UV-absorbing substances (82.4% removal rate) with a resin dose of 10 mL/L after 30 min of contact time. The MAERs could also effectively remove inorganic matter such as sulfate, nitrate and fluoride. Because of the higher specific UV absorbance (SUVA) value, the DOM in the raw water was found to be removed more effectively than that in the clarified water by NDMP resin. The temperature showed a weak influence on the removal of DOC from 6 to 26℃, while a relatively strong one at 36℃. The removal of DOM by NDMP was also affected to some extent by the pH value. Moreover, increasing the sulfate concentration in the raw water could decrease the removal rates of DOC and UV-absorbing substances.     

离子交换树脂法高效提取水中硝酸盐研究

硝酸盐是水体中重要的污染物之一,硝酸盐中的稳定氮氧同位素组成可用于有效识别其污染来源,而水体中硝酸盐的高效提取是其氮氧同位素测试的前提和关键步骤。阴离子树脂交换法提取硝酸盐是目前普遍采用的方法,但对于提取效率的影响因素还缺乏深入研究。文章通过室内实验,探讨了国产717型阴离子树脂对硝酸盐的吸附效率,以及不同洗脱剂的洗脱效率,系统研究了水体中硝酸盐高效提取过程影响因素。结果表明:12.56 mL体积的国产717型树脂对NO3-的吸附量高达200 mg以上;40 mL 4 mol/L的KCl溶液对4 cm长的吸附树脂柱(直径2 cm)的洗脱效率可达95%以上;SO42-的对NO3-的吸附和洗脱具有显著的影响。     

外源含硫化合物对土壤挥发性有机硫化合物交换通量的影响

通过静态箱采样和Entech7100预浓缩仪-GC-MS分析了半胱氨酸、硫化钠和硫酸钠对土壤吸收或释放羰基硫（COS）、二甲基硫醚（DMS）、二硫化碳（CS2）和二甲二硫醚（DMDS）等4种挥发性有机硫化合物（VOSCs）的影响.结果表明,添加半胱氨酸后,土壤由COS和CS2汇转变为源,DMS和DMDS通量显著增加,且...     

煤气湿式电除尘器洗涤水循环利用的研究

采用化学混凝、絮凝以及离子交换软化的方法处理钢厂煤气湿式电除尘器(ESP)洗涤废水,设计出小型、高效的废水处理及回用系统。以废水的SS、总硬度、总碱度为主要因子,在浓度分别为350,365,315 mg/L的条件下,经过两个主要单元的处理后,浓度可达7,75,70 mg/L,达到回用标准,降低了运行成本,环境效益显著。     

三峡库区水体多氯联苯污染特征与环境交换

为了掌握三峡库区水体多氯联苯环境污染状况,在长江三峡库区分两次采集了91件水体样品,并用气相色谱(GC-ECD)内标法分析了多氯联苯(PCBs)的含量,研究了三峡库区水体中PCBs的残留水平及其环境交换。结果表明:库区水体中PCBs的含量范围为N.D.～48.67ng/L,均值为24.34ng/L(共31种),最大值出现在朝天门,为48.67ng/L;干流断面采样点PCBs的含量仅有一个点位超过了《地表水水质标准》(GB3838—2002)标准,超标倍数为1.16倍;长江支流PCBs的分布特征是,与嘉陵江有关的采样点PCBs的含量都相对较高,其次是大宁河,但与嘉陵江同等级的乌江其含量却很低;水库中PCBs的环境交换主要集中在被淹没的土壤与库区水体之间,因此三峡大坝的蓄水和冲砂会使曾经被吸附的PCBs释放出来,导致库区水体中PCBs的含量增加。     

Arsenic in Drinking Water and Its Removal

Abstract

Superfluous arsenic in drinking water can do harm to human health. In this paper, a broad overview of the available technologies for arsenic removal has been presented on the basis of literature survey. The main treatment methods included coagulation-sedimentation, adsorption separation and ion exchange, membrane technique, which have both advantages and disadvantages. It concluded that the selection of treatment process should be site specific and prevailing conditions and no process can serve the purpose under diverse conditions as each technology has its own limitations. In order to gain good results, some methods should be improved.     

阴离子交换树脂对水杨酸的吸附与解吸性能

研究了714阴离子交换树脂对水中水杨酸的吸附与解吸性能,探讨了吸附的热力学和动力学特性.结果表明,树脂在pH=4～12时,吸附能力最好.等温吸附遵循Freundlich和Langmuir吸附平衡模型,为优惠吸附过程.在298～318K条件下,水杨酸吸附量为100～120mg/g的吸附焓变为-23.4-21.6kJ/mo...