Development of new technology for elimination of anionic species of minor toxic elements (Se, Sb, As, B) from wastewaters

1.废水中硒形态去除反应的基础研究：溶解在水溶液中的硒有四价和六价氧化态。由于含硒物质化学行为的复杂性，迫切需要对除硒技术进行系统的研究。研究了Se(IV)-Fe(III)-H_2O、Se(IV，VI)-Ca-H_2O和Se(IV，VI)-Ba-H_2O体系的平衡相图。基于这些信息，提出了从废水中去除硒的操作流程。污染土壤处理过程中粘结剂材料中氧化镁的反应：与硅酸盐水泥相比，一些以氧化镁为基础的土壤粘结剂材料表现出更环保的特性。当镁基材料与受污染的土壤和水混合时，有利于调节水相的pH值，在水相中，重金属组分被淋洗和水解为其氢氧化物消除，并通过水相中的HCO3转化为碳酸盐。氟的阴离子可以被静电捕获到在氧化镁和硅酸镁矿物组成颗粒上形成的带正电的氢氧化镁表面。利用这些镁基粘结剂材料实现了土壤中重金属离子和有毒阴离子的固定以及土壤的颗粒化。有机酸根离子对镁铝双氢氧化物的插层改性：有机酸根离子如EDTA、十二烷基硫酸盐、环烷基磺酸盐等可对无机双氢氧化物进行插层改性。具有有机酸官能团的改性氢氧化物杂化材料可以有效地清除重金属离子和双酚A等有毒有机物质。

1. Fundamental study on the reactions for elimination of selenium species from wastewaters : The selenium dissolved in aqueous solutions has 4- and 6- valence oxidation states. Due to their complicated chemical behaviors of the selenium entities, the systematic consideration of the elimination technology for selenium is urgent requisite. As the fundamental systems involved in the selenium catch as insoluble solids, Se(IV)-Fe(III)-H_2O, Se(IV, VI)-Ca-H_2O and Se(IV, VI)-Ba-H_2O systems have been investigated and equilibrium phase diagrams for these systems have been constructed. Based on these information, a stream of operations for selenium elimination from wastewaters has been proposed.2. Reactions of MgO in binder materials during processing of contaminated soils : Some MgO-based binder materials for soils show more environmentally acceptable characteristics over Portland cement. When mixed with contaminated soils and water, MgO-based materials favorably adjusted pH of water phase where the heavy-metal components are leached and hydrolyzed as their hydroxides to eliminate and MgO is converted to the carbonate through HCO_3 in the aqueous phase. The anion of fluoride Can be electrostatically trapped onto the positively charged surface of the magnesium hydroxide formed on the MgO and Mg-silicate mineral constituent particles. The immobilization of the heavy-metal ions and toxic anions as well as granulation of the soils is realized using these MgO-based binder materials.3. Modification of Mg-Al double hydroxide through intercalation of organic acid ions : Inorganic double hydroxide can be modified by intercalation of organic acid anions such as EDTA, Dodecylsulfate and Naphthane sulphonate ions. The modified hybrid materials of hydroxide with functional groups of organic acids are effectively working as scavengers for heavy-metal ions and toxic organic materials like bisphenol A.