有机酸在金属氧化物上的吸附对催化臭氧氧化的影响

以苯甲酸(BA)、邻苯二甲酸(PA)、商品腐殖酸(CHA)和反渗透法提取的松花江水腐殖酸(SHA)为目标物,研究了臭氧氧化及羟基氧化铁(FeOOH)和二氧化铈(CeO₂)为催化剂时的吸附与催化臭氧氧化去除这些有机物的效果.结果表明,BA在FeOOH表面没有吸附,FeOOH对BA催化氧化的去除率比臭氧单独氧化高45%;PA在FeOOH上的吸附使其溶液中的浓度减少了5%,此时FeOOH对PA的氧化没有催化作用.CeO₂有助于催化臭氧氧化在其表面吸附较强的PA,且对氧化产生的草酸根有催化去除作用,但对不吸附在其表面的BA没有催化臭氧氧化作用.CeO₂对腐殖酸的吸附比FeOOH强,其催化臭氧氧化去除腐殖酸的作用比FeOOH更显著;当无机阴离子和腐殖酸竞争金属氧化物表面的吸附位时,催化作用受到抑制.

Effect of Organic Acids Adsorption on Catalytic Ozonation with Metal Oxides

The effectiveness of ozonation, adsorption and catalytic ozonation with ferric hydroxide (FeOOH) and cerium dioxide (CeO₂) as catalysts on removal of several organic acids were investigated. The organic acids selected were benzoic acid (BA), phthalic acid (PA), commercial humic acid (CHA), and humic acid of Songhua River water (SHA) concentrated with reverse osmosis (RO). FeOOH was active in catalytic ozonation of the non-adsorbable BA, with 45% of BA removal higher than ozonation alone. It was inactive in case of ozonation of PA, the adsorption of which on FeOOH caused 5% reduction of its concentration. CeO₂ enhanced ozonation of PA that was strongly adsorbed, but not for the non-adsorbed BA. Oxalate ions as product of oxidation of PA were also removed by CeO₂ catalytic ozonation. As adsorption of humic acids on CeO₂ is stronger than that on FeOOH, its catalytic removal by CeO₂ was more than by FeOOH. The activity of catalytic ozonation of humic acids was scavenged in case of competition for adsorption sites on the catalysts by inorganic anions.