科研之友
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摘要
In this study, adsorptive removal of arsenic in saturated sand filters (SSF(a) and SSF(b)) containing raw and iron-coated honeycomb briquette cinders (HBC and Fe-HBC) is presented. Operating parameters including SSF design, dissolved oxygen (DO), pH, iron leaching and the effects of co-occurring ions on arsenic removal were investigated at 23 +/- 2.0 degrees C temperature for 24-days long treatment. Sampling times (ST) (5-120 min) during treatment days (TD) 1, 6, 12, 18 and 24 were purposively decided to assess filters' performance from tap water with the spiked of 200 mu g/L of As(V) and As(III) into SSF(a) and SSF(b), respectively. No other alteration or pH adjustment was made to the influent water. Results demonstrated that the removal efficiencies of arsenic in SSF(a) and SSF(b) were maintained > 95% and > 85% till TD-12 and than decreased to 78% and 60%, respectively, on TD-24. Lower arsenic removal in SSF(b) could be the result of As(III) slower oxidation at the studied influent pH under oxic conditions. Decreased in effluent DO and increased iron leaching were measured in both the filters from TD-1 to TD-24. Minor variations of effluents pH and co-occurring ions (Fluoride, Nitrate and Sulphate) were recorded, but no significant effect on arsenic removal was measured in the reported ranges. Performance of NaOH-regenerated filterbeds was evaluated and both filters removed 95% of arsenic in three-cycle treatments. This study suggests of an in situ treatment; by the oxidation of As(III) into As(V) in the presence of DO and hydroxyl radical on adsorbent surfaces, followed by subsequent adsorption through selective physical sorption and Fe-As complexation. SSF containing cost-effective adsorbents could be an effective in situ treatment option to conventional treatment for safe drinking water production.
- 出版日期2013-11
- 单位浙江大学
