铝盐和铁盐对腐殖酸混凝特性的比较

Comparison of the Properties of Coagulation between Alum Sulfate and Ferric Chloride with Humic Acids

以TOC和UV254为指标,比较了不同条件下铝盐和铁盐对腐殖酸的混凝效果。PDA在线监测结果表明,弱酸性条件下,铁盐混凝稳定性优于铝盐。HPLC分析结果表明,混凝可以有效地去除分子量大于1000的物质,且铁盐对大分子物质的去除更彻底。GC-MS分析结果表明,腐殖酸是以羧基和羟基为其主要官能团的苯环或多环类复杂大分子有机物,在弱酸性条件下,铁盐混凝对羧基类有机物的去除效果优于铝盐。但在pH为7.0的中性条件下,部分羟基和胺基类有机物不能被去除。

Jar tests were conducted respectively for the coagulation of humic acids （HA） with alum sulfate and ferric chloride as coagulants at different pH values. The removal of HA, coagulation process, molecular weight （MW） distribution and functional groups of HA were studied by TOC, UV254, a photometric dispersion analyzer （PDA 2000）, HPLC and GC-MS techniques. Combining the removal of TOC and UV254 with online monitoring of PDA 2000, it could be concluded that at pH5.0 ferric chloride had higher removal of HA than that of alum sulfate. HPLC analysis results showed that HA with MW higher than 1000Da could be removed more effectively when coagulant was ferric chloride. GC-MS analysis revealed that almost all organic matters with carboxyl and hydroxyl groups could be removed by coagulation at pH 5.0 and ferric chloride had higher removal than alum sulfate, while at pH 7.0 many hydroxyl and amidocyanogen groups could not be removed.