A pilot-scale study of cryolite precipitation from high fluoride-containing wastewater in a reaction-separation integrated reactor

Fluoride removal by traditional precipitation generates huge amounts of a water-rich sludge with low quality, which has no commercial or industrial value. The present study evaluated the feasibility of recovering fluoride as low water content cryolite from industrial fluoride-containing wastewater. A novel pilot-scale reaction-separation integrated reactor was designed. The results showed that the seed retention time in the reactor was prolonged to strengthen the induced crystallization process. The particle size of cryolite increased with increasing seed retention time, which decreased the water content. The recovery rate of cryolite was above 75% under an influent fluoride concentration of 3500 mg/L, a reaction temperature of 50℃, and an influent flow of 40 L/hr. The cryolite products that precipitated from the reactor were small in volume, large in particle size, low in water content, high in crystal purity, and recyclable.     

明胶厂剩余高钙污泥作为燃煤固硫剂的应用研究

明胶生产产业在废水处理工艺中产生大量剩余高钙污泥,采用该剩余污泥作为燃煤固硫剂,在高温管式电阻炉内进行燃烧实验,通过测定燃烧前和燃烧后样品中的硫含量确定该剩余污泥的固硫效果。通过单因素研究煤粉粒径、剩余污泥粒径和剩余污泥/煤样%等影响因素对固硫率的影响。在单因素试验的基础上通过正交设计法优选达到较高固硫率的实验条件。实验结果表明:影响固硫率的因素从大到小依次为燃烧温度>剩余污泥/煤样%>煤粉粒径>剩余污泥粒径。以剩余污泥作为固硫剂,固硫率最高的实验条件为:燃烧温度800℃,剩余污泥/煤样为3%,煤粉粒径60⁹0目,剩余污泥粒径9090目,剩余污泥粒径90¹20目。并且,当温度达到1150℃,煤粉粒径90120目。并且,当温度达到1150℃,煤粉粒径90¹20目,剩余污泥粒径为60120目,剩余污泥粒径为60⁹0目,污泥/煤样(质量比)为3%时,固硫率可达62.78%,说明在高温下该剩余污泥保持较高的固硫率。将明胶厂剩余污泥作为固硫剂是较为合适的再利用方法,可有效缓解当前该污泥大量堆积污染环境的状况。     

基于层次分析法（AHP）的环境绩效审计评价体系构建研究——以丽水市为例

文章构建了环境绩效审计综合评价指标体系,运用层次分析法确定指标体系的权重,对于提高环境绩效审计工作质量和效率具有重要意义。丽水市生态资金绩效审计的实证研究结果表明,指标体系评价结果能客观反映市县行政区实际,指明影响环境管理绩效的消极因素,能有效提高财政经费使用效益,充分发挥审计服务科学发展的作用。     

酞菁-二氧化钛光催化剂的制备及其光催化降解效果

采用溶胶-凝胶法制备酞菁-TiO2光催化剂,并分别掺杂铁、铜、钴、镍元素。酞菁作为光敏化剂,提高TiO2在可见光下对有机染料的降解效果。采用SEM对催化剂进行表征,研究在可见光下酞菁-TiO2光催化剂对5种有机染料(甲基橙、甲基红、甲酚紫、亚甲基蓝和孔雀石绿)的降解效果,结果表明,酞菁铁-TiO2,酞菁钴-TiO2,酞菁铜-TiO2,酞菁镍-TiO2均能有效降解这几种有机染料,光催化反应300 min后降解率达92%。比较4种催化剂对甲基橙的降解率,酞菁钴-TiO2催化剂降解效果最明显,以下是酞菁铁、酞菁镍和酞菁铜-TiO2催化剂。     

排污权交易之排放跟踪数据校核研究

本文以排污权交易的核心业务排放跟踪管理为出发点,选择电厂二氧化硫指标进行排放跟踪数据过程校核体系研究,探索进一步提高排污权交易体系中排放数据准确性的机制。     

站控、通信及网络系统的防雷措施

论述了输油泵站控制系统及微波通信系统遭受雷击的危害及原因,有针对性地采取了各种防雷的有效措施,完善微波通讯和站控及网络防雷保护系统,为确保输油安全生产提供了有利保证.     

硫酸系统水平衡分析计算和生产实践

在硫酸系统中,通过水平衡分析计算烟气带入净化工序的SO2体积分数和含水量,确定净化工序的能力,控制干燥塔进口烟气温度,使干吸工序生产出合格产品;通过计算,烟气带入净化工序的水量小于产品带出的水量,制酸净化污水经过污水处理工序处理后返回到净化工序重复使用,实现净化污水零排放,消除对环境的污染.     

Removal of copper ions from aqueous solution by calcium alginate immobilized kaolin

Kaolin has been widely used as an adsorbent to remove heavy metal ions from aqueous solutions. However, the lower heavy metal adsorption capacity of kaolin limits its practical application. A novel environmental friendly material, calcium alginate immobilized kaolin (kaolin/CA), was prepared using a sol-gel method. The e ects of contact time, pH, adsorbent dose, and temperature on Cu2+ adsorption by kaolin/CA were investigated. The Langmuir isotherm was used to describe the experimental adsorption, the maximum Cu2+ adsorption capacity of the kaolin/CA reached up to 53.63 mg/g. The thermodynamic studies showed that the adsorption reaction was a spontaneous and endothermic process.     

Structural and electrochemical properties of annealed La1-xYxNi3.55Mno.4Alo.3Coo.75 hydrogen storage alloys

The effects of the annealing and partial substitution of Y for La on the structural and electrochemical properties of La_1-xY_xNi_3.55Mn_o.4Al_o.3Cr_o.75 (x = 0, 0.1 and 0.2) alloys were reported in the present work. The single-phased CaCu₅-type structure was retained after La was partially substituted by Y. However, the increase of Y content leads to decrease of the lattice parameters and the unit-cell volume. The annealed La_o.9Y_o.1Ni_3.55Mn_o.4Al_o.3Co_o.75 alloys shows typical isometric microstructure, indicating that the composition segregation is improved by annealing. Y substitution for La in the alloys is effective to improve the electrochemical properties at both room temperature and high temperature. A critical substitution content of Y is found at x = 0.1.     

农村环境污染现状及治理对策

文章结合农村实际情况,从环境保护的角度分析了当前农村存在的主要环境污染问题及其成因,并提出了相应的治理对策措施。