铁-亚硫酸盐配合物体系氧化处理硫酸厂的含砷废水

OXIDATION AND REMOVAL OF ARSENIC-CONTAINING WASTEWATER FROM SULFURIC ACID FACTORY BY IRON-SULFITE COMPLEX SYSTEM

研究了铁-亚硫酸盐配合物体系处理实际硫酸厂高浓度含砷废水的工艺与影响条件。结果表明,铁-亚硫酸盐配合物在溶解氧参与下反应产生硫酸自由基,氧化废水中的As(III)产生As(V),然后升高pH,导致铁形成氢氧化物沉淀,从而使得砷被絮凝沉淀去除。絮凝-氧化-再絮凝的工艺优于直接氧化-絮凝工艺;在pH=3、n(Fe(III))/n(As)=1/10、n(亚硫酸钠)/n(As)=5、氧化、絮凝时间均为30 min条件下,直接氧化-絮凝工艺总砷去除率可以达到98.5%;絮凝-氧化-再絮凝的工艺As(III)去除率达到99.6%,总砷去除率达到99.9%,处理过后,砷含量由500 mg/L降为2mg/L,很容易通过进一步的吸附处理达到排放标准。

This work investigated the application of iron-sulfite complexes in the treatment of concentrated arsenic-containing wastewater from a sulfuric acid plant. The processes and influencing conditions were studied. The results show that iron sulfite complexes together with dissolved oxygen produce sulfate radical. Oxidation of As（Ⅲ） to As（V） by sulfate radicals in wastewater was fast. After oxidation, the pH was increased and the formation of the precipitation of iron hydroxide resulted in the removal of arsenic. The flocculation-oxidation-flocculation process is better than the direct oxidation-flocculation process in the removal efficiency of total Arsenic. Under the conditions ofpH 3, Fe（Ⅲ）/As ratio 1/10, sulfie/As ratio 5, oxidation and flocculation time 30 min, direct oxidation-flocculation process removed 98.5% total arsenic. The flocculation-oxidation-flocculation process removed 99.6% As（Ⅲ） and 99.9% the total arsenic. The total arsenic concentration was reduced from 500 mg/L to 2 mg/L, which makes it easy to meet the discharge standards through further adsorption.