The effectiveness of a China-made high-quality DTCR (dithiocarbamate type chelating resin) in softening hard water, direct precipitation of hexavalent chromium, and treatment of single and mixed electroplating wastewater was evaluated through tests and compared with sulfide precipitation method. The selection of pH, stability of precipitates, and difficulty of operation were discussed. The results showed that when the pH was lowered down to ca.3.5, the precipitates produced were dissolved totally with low dosage of DTCR, but mostly with high dosage of DTCR. When the supernatant obtained by filtration of the DTCR treated copper and nickel-containing wastewater was added with sodium sulfide solution, precipitates were formed. DTCR brings about neutralization/precipitation actions for ions such as Cu2+ and Ni2+ under alkaline condition, but has a lower removal efficiency than the sulfide precipitation method.%试验了一种国产优质DTCR(二硫代氨基甲酸型螯合树脂)在硬水软化、直接沉淀六价铬,单一及混合电镀废水处理等方面的应用效果,讨论了pH的选择、沉淀物的稳定性以及实际操作的困难性,并与硫化物沉淀法进行了比较.结果表明:当DTCR的加入量不大时,生成的沉淀在pH下调至约3.5时全部溶解;当DTCR的加入量较大时,混合沉淀物大部分溶解.过滤用DTCR处理过的铜镍废水后,在上清液中加入硫化钠溶液后又再有沉淀生成.可见,在碱性条件下DTCR仍以中和沉淀为主,其对Cu2+、Ni2+等的去除效果不如硫化物沉淀彻底.
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