Optimization treatment of sludge heavy metals by citric acid and GLDA

被引：0
作者：
Xu D. [1 ]
Hong Y. [1 ]
Tang H. [1 ]
Cheng W. [2 ]
Song Z. [1 ]
Zhan L. [1 ]
Yao Q. [1 ]
机构：
[1] Department of Biological and Chemical Engineering, Anhui Polytechnic University, Wuhu, 241000, Anhui
[2] Chery Automobile Co., Ltd., Wuhu, 241009, Anhui
来源：
Huagong Xuebao/CIESC Journal | 2017年 / 68卷 / 06期
基金：
中国国家自然科学基金;
关键词：
Citric acid; Environment; GLDA; Heavy metals; Optimal design; Orthogonal experiment; Pollution; Removal rate;
D O I：
10.11949/j.issn.0438-1157.20170001
中图分类号：
学科分类号：
摘要：
High heavy metals content is the major drawback of sludge resource, especially for sludge derived from industrial wastewater treatment plan. Citric acid and GLDA were used to treat sludge heavy metals in the present study, and the effects of the reagent concentration, pH and reaction time of citric acid and GLDA on the availability and removal of sludge heavy metals were investigated. An orthogonal experiment was performed to obtain the optimum reaction condition of CA and GLDA treatment of the sludge heavy metals. The results indicated that the higher reagent concentrations and the lower pH led to the higher removal rate of heavy metals, but the effect of longer reaction time on heavy metal removal was not obvious. The best conditions of CA and GLDA treatment of sludge heavy metals were: CA 0.3 mol·L-1, pH=4 and reaction time 2 h, and GLDA 0.05 mol·L-1, pH=4 and reaction time 3 h. Under the optimum reaction conditions of the CA and GLDA, the removal rate of Cd, Cu, Pb and Ni can reach 80.25%, 77.75%, 64.66% and 75.16%, and 78.57%, 78.48%, 64.84% and 76.71%, respectively. Both of CA and GLDA, the removal efficiency of heavy metals was ranged as Cd>Cu> Ni>Pb, but the effect of GLDA treatment was better than that of CA. After CA and GLDA treatment, the acid-soluble contents of heavy metals in the solid phase of sludge decreased most and reached an average of 81%, the residual contents decreased an average of 52.1%, and the heavy metals in the liquid phase of sludge increased an average of 17.54 times, leading to the transfer of the heavy metals from the solid phase into liquid phase. SEM observation showed that the flocculent structure of sludge was replaced obviously by mass structure and the layered structure after treatment. And at the same time, the adsorption ability and volume were reduced. The research results showed that the CA and GLDA treatment of sludge can effectively reduce the sludge heavy metal content and improve the chemical stability of heavy metals in solid phase of sludge, which was advantageous to the sludge dehydrating and its further processing and utilization. © All Right Reserved.
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页码：2535 / 2545
页数：10
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