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研究了活性炭(activated carbon,AC)吸附、改性活性炭(activated carbon modified,ACM)吸附、过氧化氢(H2O2)氧化、AC催化H2O2等方法对水体中荧光增白剂VBL的处理效果,并通过自由基俘获剂叔丁醇、催化过程气体分析等探讨了AC催化H2O2分解VBL的机制.结果表明,经硝酸铁[Fe(NO3)3]改性过的ACM对VBL的吸附去除率高于未改性的AC.活性炭催化H2O2对VBL的去除效果明显,但未改性AC催化去除率高于ACM.60 min时,AC催化氧化去除率即可达到95%以上,而ACM仅为58%.叔丁醇的加入降低了AC和ACM催化氧化对VBL的去除率,表明AC催化H2O2氧化能促进H2O2形成羟基自由基(·OH)和原子氧参与反应.AC催化H2O2分解及释放气体分析表明,AC能催化H2O2形成氧气并放热,且ACM明显快于AC.结合催化H2O2去除VBL效率的结果分析,ACM催化反应时活性中间物(自由基和原子氧等)产生速率快于AC,活性中间物自身消耗形成氧气,而不是用于分解VBL.催化反应中活性中间产物的形成速率与反应物供给速率的不匹配可能是导致ACM催化效果弱于AC的重要原因.
The effects of activated carbon (AC) adsorption, activated carbon modified (ACM) adsorption, hydrogen peroxide (H2O2) oxidation and AC-catalyzed H2O2 on the fluorescent whitening agent VBL in water were studied. Free radical scavenger tert-butanol and catalytic gas analysis were used to investigate the mechanism of AC degradation of VBL by H2O2. The results showed that the adsorption and removal rate of VBL by ACM modified by ferric nitrate [Fe (NO3) 3] Activated carbon modified H2O2 for VBL removal effect is obvious, but the unmodified AC catalytic removal rate higher than ACM.60 min, AC catalytic oxidation removal rate can reach more than 95%, while the ACM is only 58%. The addition of tert-butanol reduced the removal rate of VBL by AC and ACM catalytic oxidation, indicating that AC catalyzed oxidation of H2O2 can promote the formation of hydroxyl radical (· OH) and atomic oxygen in H2O2 reaction.AC decomposition of H2O2 and gas evolution analysis showed that, AC can catalyze H2O2 to form oxygen and exotherm, and ACM is obviously faster than AC. Combining the results of H2O2 removal VBL efficiency, ACM catalytic reaction of active intermediates (free radicals and atomic oxygen, etc.) faster than AC, active intermediate Consumption of oxygen to form their own objects, rather than for points VBL. The rate of formation of reactive intermediates catalyzed reaction does not match the feed rate of the reactant may be an important cause of the catalytic effect is weaker than the AC ACM.