石灰沉淀法除砷的影响因素
Influencing factors of arsenic removal by lime precipitation
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摘要: 以Ca(OH)2溶液为沉淀剂,处理模拟含砷废水砷酸钠溶液,考察了pH值 、Ca/As摩尔比、自由沉降时间和反应温度等因素对石灰沉淀法除砷效果的影响。结果表明,在pH值为12,Ca/As摩尔比为6,沉降时间为48 h,反应温度为25℃时,石灰沉淀法除砷的效率可达到99.05%;此外,对高浓度的含砷废水,在石灰沉淀法除砷工艺中添加简单无机盐絮凝工艺,可显著降低出水总砷浓度,达到污水综合排放标准的要求。Abstract: With the Ca(OH)2 solution for precipitation agent and the sodium arsenate solution for simulation arsenic water, the effects of pH, the Ca/As molar rations, the precipitate time and the temperature on arsenic removal by lime precipitation were studied. The results showed that , while controlling the pH was 12, the mole ratio of Ca/As was 6, the time of precipitate was 48 hours and the temperature was 25℃, the removal rate of arsenic rose to 99.05%. Besides, when adding the inorganic flocculants to high concentration of arsenic wastewater treated with Ca(OH) 2 solution, the effluent concentration of arsenic wastewater could be significantly reduced,then met the requirements of integrated wastewater discharge standard.
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Key words:
- lime precipitation /
- pH /
- Ca/As molar ratios /
- inorganic flocculant
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