电凝聚法去除废水中重金属离子Cr^(6+)、Cu^(2+)的研究

Removal of Heavy Metal Ions Cr^(6+) and Cu^(2+) from Wastewater by Electrocoagulation Process

考察了初始pH值、电解时间、电流强度、NaCl投量、离子共存及曝气量等因素对电凝聚法处理含Cr6+、Cu2+废水的影响。结果表明,随初始pH值的升高,对Cr6+的去除率呈先上升后下降的趋势,并在pH值=6时达到最高,而对Cu2+的去除率逐渐上升,并在pH值=5时达到最高后趋于稳定;对Cr6+、Cu2+的去除率均随反应时间及电流强度的增大而增大,并在时间为20min、电流强度为4 A时达到了比较稳定的去除效果;NaCl投量对Cr6+、Cu2+的去除率基本没有影响,其作用是适当地提高废水的电导率,降低能耗;对混合溶液中Cr6+、Cu2+的去除效果比单一溶液时好,金属离子共存对电凝聚处理重金属废水起促进作用;适当的曝气会提高重金属的去除率。

The influences of parameters NaC1 dosage, ion coexistence and aeration rate such as initial pH, coagulation time, current intensity, on treatment of wastewater containing Cu2＋ and Cr6＋ by electrocoagulation process were investigated. The results showed that with the increase of initial pH, the removal rate of Cr6＋ was first increased and then decreased, and reached the highest level at pH of 6, while the removal rate of Cu2＋ was increased gradually and reached the highest level at pH of 5 and then stable. The removal rates of Cr6＋ and Cu2＋ were increased with the increase of coagulation time and current intensity, and reached a relatively stable level at 20 min and 4 A. NaC1 dosage had no effect on the removal rates of Cr6＋ and Cu2＋ , and its role was to increase the electrical conductivity of water and re- duce energy consumption. The treatment effect of Cr6＋ and Cu2＋ in mixed solution was better than that in single solution, and the coexistence of metal ions had a beneficial effect on removing the heavy metal ions in wastewater. Proper aeration could increase the heavy metal removal rate.