高锰酸钾强化三氯化铁共沉降法去除亚砷酸盐的效能与机理

Effectiveness and Mechanism of Permanganate Enhancing Arsenite Co-Precipitation with Ferric Chloride

研究了不同水质条件下KMnO4强化FeCl3 共沉降去除亚砷酸盐 [As(Ⅲ ) ]的效能与机理 .考察了pH值、天然有机物(NOM )等因素对As去除效能的影响 .结果表明 ,投加KMnO4显著提高了FeCl3 共沉降除砷 (FCP)工艺对As(Ⅲ )的去除效能 .随着Fe(Ⅲ )投量由 2 0mg/L增大到 8 0mg/L ,对于FCP工艺 ,As去除率由 4 1 3%提高到 75 4 %;而对于KMnO4 FeCl3共沉降除砷 (POFCP)工艺 ,As去除率则由 6 1 2 %提高至 99 3%.FCP及POFCP工艺对As的去除率均随着pH值的升高而升高 ;与FCP工艺比较 ,pH值对POFCP工艺除As效果影响较小 ;NOM降低了FCP工艺对As的去除率 ,而对POFCP工艺无明显影响 .KMnO4的氧化作用是强化As(Ⅲ )去除效能的主要因素 ,而KMnO4的还原产物水合MnO2 (s)对As(Ⅲ )也具有一定的去除能力 .POFCP工艺是强化去除水中As(Ⅲ ) ,以保障安全饮用水供给的有效方法 .

The effectiveness and mechanism of permanganate enhancing arsenite (As(Ⅲ)) co-precipitation with ferric chloride is investigated. Effects of parameters such as pH, natural organic matter (NOM) on As removal are studied. Permanganate significantly enhances As(Ⅲ) removal for ferric co-precipitation (FCP) process. With Fe(Ⅲ) dosage increasing from 2mg/L to 8mg/L, As removal increased from 41.3% to 75.4% for FCP process; for permanganate oxidation-ferric co-precipitation (POFCP) process, however, corresponsive As removal increased from 61.2% to 99.3%. As removal increased with higher pH for both processes; comparing to FCP process, pH had less effects on As removal for POFCP process; the presence of NOM reduced As removal for FCP process whereas no obvious reduction was observed for POFCP process. Permanganate oxidizing As(Ⅲ) to As(Ⅴ) is the main course for enhancing As(Ⅲ) removal; furthermore, products of permanganate reduction, hydrous MnO 2(s), also contribute to removing As. POFCP process exhibits good potential of removing As(Ⅲ) to assure chemical safety of drinking water.