三氯化铁混凝除砷机理的研究
发布时间：2019-03-09 13:54
【摘要】：砷可以通过自然途径和人为途径进入水环境，水中的砷主要是无机砷，毒性较大，长期饮用高砷水会影响人体健康，因此无机砷的去除及其影响因素和机理的研究具有很重要的价值。 本文通过研究pH=5-10的范围内，混凝产生的胶体的Zeta电位变化，经过沉淀过滤后溶液中三价砷和五价砷的去除率，分析三氯化铁混凝去除水中砷的机理，以及背景溶液氯化钠浓度由1mM提高到10mM时、水中氢氧化钙浓度为50mg/L或氯化镁浓度为64.31mg/L时，对混凝效果的影响。 本文首先进行高效液相色谱测定砷含量的研究。经实验确定，HPLC-ICP-MS的最佳流动相是，，浓度为20mM的NH_4H_2PO_4溶液（pH值为6.0）和甲醇溶液，比例为97%：3%，此时三价砷和五价砷的分离及测定效果较好。 混凝实验结果表明，胶体的Zeta电位呈先升高后下降的趋势，在pH=7-8之间达到等电点；三价砷在pH较高时去除效果好，在pH较低时去除效果差，而五价砷正好相反。钙离子或镁离子的加入会减小Zeta电位，提高五价砷的去除率，但三价砷的去除率不受影响。在pH=9时，投加金属离子，总砷去除率最大。
[Abstract]:Arsenic can enter the water environment through natural and man-made ways. The arsenic in the water is mainly inorganic arsenic, which has great toxicity. Drinking high arsenic water for a long time will affect human health. Therefore, it is of great value to study the removal of inorganic arsenic and its influencing factors and mechanism. In this paper, through studying the change of Zeta potential of colloid produced by coagulation in the range of pH=5-10, the removal rate of trivalent and pentavalent arsenic in the solution after precipitation filtration was studied, and the mechanism of ferric chloride coagulation to remove arsenic in water was analyzed. And when the concentration of sodium chloride in background solution is increased from 1mM to 10mM, and when the concentration of calcium hydroxide in water is 50mg/L or the concentration of magnesium chloride is 64.31mg/L, the effect of the concentration of calcium hydroxide in water on the coagulation effect is also discussed. In this paper, the determination of arsenic by high performance liquid chromatography (HPLC) was studied. The best mobile phase of HPLC-ICP-MS is NH_4H_2PO_4 solution (pH = 6.0pH) and methanol solution with the concentration of 20mM, and the ratio is 97% ~ 3%. The separation and determination of trivalent arsenic and pentavalent arsenic are better. The results of coagulation experiment showed that the Zeta potential of colloid increased first and then decreased, reaching isoelectric point between pH=7-8, and the removal effect of trivalent arsenic was better when pH was higher than that when pH was lower, but that of pentavalent arsenic was just the opposite. The addition of Ca ~ (2 +) or mg ~ (2 +) can decrease the Zeta potential and increase the removal rate of pentavalent arsenic, but the removal rate of trivalent arsenic is not affected. When adding metal ions in pH=9, the removal rate of total arsenic is the highest.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU991.2
本文编号：2437521
[Abstract]:Arsenic can enter the water environment through natural and man-made ways. The arsenic in the water is mainly inorganic arsenic, which has great toxicity. Drinking high arsenic water for a long time will affect human health. Therefore, it is of great value to study the removal of inorganic arsenic and its influencing factors and mechanism. In this paper, through studying the change of Zeta potential of colloid produced by coagulation in the range of pH=5-10, the removal rate of trivalent and pentavalent arsenic in the solution after precipitation filtration was studied, and the mechanism of ferric chloride coagulation to remove arsenic in water was analyzed. And when the concentration of sodium chloride in background solution is increased from 1mM to 10mM, and when the concentration of calcium hydroxide in water is 50mg/L or the concentration of magnesium chloride is 64.31mg/L, the effect of the concentration of calcium hydroxide in water on the coagulation effect is also discussed. In this paper, the determination of arsenic by high performance liquid chromatography (HPLC) was studied. The best mobile phase of HPLC-ICP-MS is NH_4H_2PO_4 solution (pH = 6.0pH) and methanol solution with the concentration of 20mM, and the ratio is 97% ~ 3%. The separation and determination of trivalent arsenic and pentavalent arsenic are better. The results of coagulation experiment showed that the Zeta potential of colloid increased first and then decreased, reaching isoelectric point between pH=7-8, and the removal effect of trivalent arsenic was better when pH was higher than that when pH was lower, but that of pentavalent arsenic was just the opposite. The addition of Ca ~ (2 +) or mg ~ (2 +) can decrease the Zeta potential and increase the removal rate of pentavalent arsenic, but the removal rate of trivalent arsenic is not affected. When adding metal ions in pH=9, the removal rate of total arsenic is the highest.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU991.2
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