The efficient removal of chloride ion(Cl-)is a bottleneck problem in the field of the recycling of waste acid generated from the nonferrous metallurgy.In recent years,advanced oxidation process has shown great application potential in removal of Cl-.In this paper,the dechlorination efficiency,mechanism,cost and operation management of lead dioxide(PbO2),sodium bismuthate(NaBiO3)and potassium peroxymonosulfate(PMS)were compared and analyzed.In order to achieve the residual Cl-concentration of less than 200 mg/L for the requirements of waste acid reuse,the dosage of PbO2,NaBiO3 and PMS were 4,1.5 and 1.5 times of the theoretical value,while the required reaction temperature were 50,20 and 60℃,respectively.The regeneration of PbO2 and NaBiO3 were realized by mixing the dechlorination solid products with chlorine gas absorption solution,and the dechlorination efficiency of the regenerated reagents were higher than 90%in five cycles.Highly active intermediate species such as hydroxyl radical(·OH),sulfate radical(·SO-4)and chlorine radical(·Cl)were involved in the dechlorination processes of PbO2,NaBiO3 and PMS.The contribution of direct oxidation,indirect oxidation of·OH and indirect oxidation of·SO-4 for dechlorination process of PMS were about 84%,9%and 7%,respectively.In terms of practical application value,NaBiO3 has more advantages in cost and energy consumption due to its renewability,high by-product recovery value and low reaction temperature,while PMS is simpler in terms of operation and management because it does not introduce impurities.
关键词
脱除氯离子/强酸性废水/二氧化铅/铋酸钠/过硫酸氢钾(PMS)/高级氧化
Key words
Cl-removing/strongly acidic wastewater/PbO2/NaBiO3/PMS/advanced oxidation process
维普
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