溶剂萃取法处理高含量6价铬废水

THE TREATMENT OF Cr(VI) WITH HIGH CONCENT FROM WASTEWATER BY THE PROCESS OF SOLVENT EXTRACTION

研究了含高含量6价铬废水的溶剂萃取处理方法,分别考察了萃取反应p H条件、萃取剂含量、有机相配比和废水中SO42-的存在等对萃取效率的影响规律,并进行了反萃过程研究。结果表明,优化萃取条件为:室温条件下料液p H为6,萃取有机相中Aliquat336用量为0.5 mol/L,稀释剂磺化煤油与Aliquat336的体积比为1/1,调节剂十二醇用量为总有机相体积的8%;无需预处理去除原液中的高含量SO42-,可实现最高萃取率99.9%。此条件获得的负载有机相经过质量分数20%的Na Cl溶液进行反萃,其过程受p H影响显著,反萃过程在严格控制p H稳定于12的前提下,可获得最高反萃率94.6%。

Solvent extraction process was used for treating wastewater with high content of hexavalent chromium. The effects of pH of feed, extractant concent, the volume ratio between organic solvent and the presence of high concent of sulfuric ion on extraction efficiency were investigated. Furthermore, the stripping process was also investigated. According to the results, adjusting wastewater pH to 6 could promote the extracting efficiency. The optimum extracting condition could be concluded as wastewater pH at 6, the dosage of extractant Aliquat336 at 0.5 mol/L, volume ratio between Aliquat336 and kerosene as 1/1, and regulator lauryl alcohol volume at 8% of total organic phase. Under this condition, pretreatment of high concentration of sulfuric ion from feed is not required and the extraction rate achieved as high as 99.9%. The loaded organic phase obtained alter extraction process at this condition was stripped by 20% mass fraction of NaCl and the process was significantly affected by the pH of stripping solution. The highest stripping rate （94.6%） could be obtained if the pH of the stripping solution was maintained at 12, strictly.