摘要
以含Ni2+废水作为处理对象,主要研究了几个影响高分子重金属絮凝剂去除废水中Ni2+的因素,从而进一步了解高分子重金属絮凝剂的结构和性能.实验结果表明:(1)某些离子存在时,pH值对Ni2+的最高去除率影响不大;(2)水中某些二价阳离子的存在不仅不会消耗高分子重金属絮凝剂的用量,而且会促进Ni2+絮凝沉淀,Ni2+的去除率均在95%以上;(3)水中Fe3+会与Ni2+竞争高分子重金属絮凝剂分子中二硫代羧基上的配位基,若高分子重金属絮凝剂投加量不足,Fe3+的存在将影响螯合体MHMF Ni2+的生成;(4)Ni2+和致浊物质会互相促进彼此的去除,浊度的去除率在97%以上.(5)高分子重金属絮凝剂对重金属离子具有选择性,可将部分重金属离子从其它离子中分离开、回收再利用.
A novel approach for metal sequestration by the chelating and flocculating capabilities of water-soluble Macromolecule Heavy Metal Flocculant was introduced by using Ni^(2+) in wastewater as the target metal ion. The basic principle of removing heavy metal ion and turbidity with Macromolecule Heavy Metal Flocculant was mainly discussed, some factors which affected the removal rates in wastewater were also studied. The experimental results showed that: (1) Though the tendency of influence on the removal of Ni^(2+) and turbidity was opposite with pH value changed, an optimum pH existed, and removal rates of Ni^(2+) and turbidity were both above 95% when the pH value was at 5.5. The pH value had little effect on the maximum removal rate of Ni^(2+) when some other ions (such as Ca^(2+),Mg^(2+) ) also existed; (2) The existence of some bivalent ions (such as Ca^(2+)) in wastewater not only consumed none of Macromolecule Heavy Metal Flocculant, but also promoted the flocculation and sedimentation of Ni^(2+). The existence of Ca^(2+) made the double electricity layer thinner, speeded up the flocculation-sedimentation and broadened the range of the optimum input of Macromolecule Heavy Metal Flocculant. Therefore a better removal result was obtained, which could be advantagous to practical application. It was determined by two characteristics of Ca^(2+): firstly, Ca^(2+) was not easy to react with Macromolecule Heavy Metal Flocculant. Secondl, Ca^(2+) had a higher positive charge; (3) Fe^(3+) and Ni^(2+) in wastewater competed for the ligand dithioic acid of Macromolecule Heavy Metal Flocculant, so the chelate production of MHMF-Ni^(2+) was affected by the existence of Fe^(3+) if the Macromolecule Heavy Metal Flocculant was not enough. On the contrary, the maximum removal rate of Ni^(2+) was higher than that when Fe^(3+) was absent;(4) Some factors such as charge neutralization as well as metal bridging contributed to the subsequent precipitation and separation of the chelate of MHMF-Ni^(2+) when Ni^(2+) was present. A
出处
《环境科学学报》
CAS
CSCD
北大核心
2005年第2期180-185,共6页
Acta Scientiae Circumstantiae
基金
国家自然科学基金项目(批准号:20377020)
