利用柠檬酸去除污泥中重金属的新工艺

经柠檬酸络合后采用离子交换法处理污泥中的重金属,该方法包括3个步骤:浸提过程、固液分离、浸提液的净化和循环。对影响浸提液的净化和循环步骤中的主要影响因素进行了研究。结果表明,732型阳离子交换树脂性能优异,对重金属的离子交换率接近100%;以5%HCl溶液为洗脱剂,动态逆流操作条件下,Cu、Ni和Zn的洗脱率分别达到88.85%、86.15%和88.40%;以铝片为置换剂,对重金属Pb、Cd、Cu、Ni都能得到90%以上的置换率。循环实验表明,处理后污泥中的重金属含量符合《农用污泥中污染物控制标准》(GB4284-84),柠檬酸可以实现循环使用。

A NEW TECHNICS ON REMOVAL OF HEAVY METALS FROM SEWAGE SLUDGE WITH CITRIC ACID

A new technique on removal of the heavy metals from sludge has been brought forward, which consists of three steps: extraction, separation of solids and liquid, cleaning and recycling of extracting liquid. The main factors on the third step have been studied. The following results have been received: 732# action resin has excellent capacity, whose ion exchange rate for heavy metals reaches almost 100%. The regeneration rate of Cu, Zn and Ni respectively reaches 88.85%, 86.15% and 88.40% with 5% HCl by dynamic counter flow operation. Replacement rate of most heavy metals can be reached above 90% with Aluminum piece. Recycling experiment proves that not only the content of heavy metals in the sewage sludge after treatment accords with standard, but also the citric acid can be recycled.