γ-Al2Ｏ3催化臭氧氧化水中嗅味物质MIB效能研究

以γ- Al₂Ｏ₃粉末为催化剂,研究了催化臭氧氧化去除水体中典型嗅味物质2-甲基异茨醇（MIB）的效能及相关影响因素.研究表明,γ- Al₂Ｏ₃在蒸馏水和自来水本底中,均表现出显著的催化活性.在蒸馏水本底条件下,催化氧化可提高MIB去除率47个百分点;而在自来水本底条件下,可提高MIB去除率40个百分点以上.臭氧浓度、催化剂投加量和MIB的初始浓度对催化氧化过程具有明显的影响作用.水的硬度对γ- Al₂Ｏ₃催化臭氧氧化MIB影响不大,但水中无机阴离子对催化效果影响显著.天然水体中的重碳酸盐/碳酸盐碱度可以抑制催化臭氧氧化过程中产生的羟基自由基,对γ- Al₂Ｏ₃催化臭氧氧化MIB起到了抑制作用.低浓度的腐殖酸能够促进催化氧化过程,而高浓度时则有抑制作用.通过pH值对催化氧化MIB的影响和叔丁醇对催化氧化的抑制作用,间接地证明γ- Al₂Ｏ₃催化氧化MIB的作用机理是以羟基自由基为主的间接氧化过程.

Gamma-Al2O3 catalyzed ozonation for removing taste and odor substance 2-methylisoborneol in drinking water

gamma-Alumina was used as a catalyst in ozonation, and efficiency and influencing factors in degradation of taste and odor substance 2-methylisoborneol (MIB) in drinking water were studied. The result shown that gamma-alumina was activated in catalytic ozonation for degradation MIB not only in distilled water, but also in tap water. In distilled water condition, catalyzed ozonation could enhance 47% removal efficiency; in tap water condition, catalyzed ozonation could increase 40% removal efficiency. The concentration of ozone, gamma-alumina, MIB can affect the degradation of MIB observably. gamma-Alumina catalyzed ozonation for removing MIB did not depend on rigidity in water, but was affected by inorganic negative ions. By capturing the hydroxyl radicals produced by gamma-alumina catalyzed ozone decomposition, the bicarbonate/carbonate in natural water can restrain the effect of gamma-alumina catalyzed ozonation for degradation of MIB. Lower concentration of humic acid can promote the effect of oxidation of the MIB, but higher concentration of humic acid may reduce the efficiency. As pH values can affect the process of catalyzed ozonation and tert-butyl alcohol can inhibit the efficiency of catalyzed ozonation efficiency of MIB, the mechanism of gamma-alumina enhanced ozone oxidation of MIB can be identified as that gamma-alumina catalyzed ozone to decompose into hydroxyl radicals which further break up the molecule of MIB.