Study On Degradation Of Adsorbed Phenol Under Irradiation Of Microwave Coupled With Ultraviolet

Microwave coupled with UV oxidation which showed many advantage, such as complete oxidation and fast response compared with the traditional process, was a novel advanced oxidation technology developed in recent years. And it was applied widely for the treatment of organic pollutants in the wastewater, while there was little report about the treatment of vapor organic contaminants(VOCs). The VOCs showed persistent and long term delaying when it was discharged by factory. Accordingly it is necessary to take advantage of the adsorbent adsorption- microwave coupled with UV oxidation combined process to treat the matters. In this paper, the new adsorbent of activated carbon loaded with Zirconium was prepared, and was applied in degradation of adsorbed phenol in the combined process. In addition the surface structure and regeneration of the adsorbent, the degradation pathway of phenol were discussed in this paper.In this paper, the new activated carbon loaded with ZrO2 was prepared by the ion exchange sol-gel method, with ZrClO2.8H2O as zirconium source. By degradation of phenol experiments under microwave electrodeless lamp radiation, The preparation conditions was optimized. The activated carbon loaded with ZrO2 was perfect when it was prepared after the activated carbon surface modified by 30% NaOH solution, CZr = 0.5mol/L, with the ratio of zirconium sol and activated carbon was 20mL/ 12g, 500℃roasted 3h, loaded with Zr twice. The adsorbent were characterized by BET, SEM, XPS, and indicate that: the content of zirconium was 8.99%, absolutely composed by ZrO2. The new adsorben has a similar pore structure to original activated carbont. The average pore size was about 2 nm and its specific surface area was 902.65 m2/g.The various process conditions affected the degradation process of the adsorbed phenol in the microwave UV system was studied, With Phenol degradation rate and loss rate of adsorbent regeneration as evaluation indicators, to determine the optimum conditions were: air flow 0.2L/min, microwave output power 460W, irradiation time of 5min. In this process conditions, phenol degradation was 93%. By comparing of the microwave coupling UV technology and microwave alone technology, provide reference for the practical applications selection.Comparison of ordinary activated carbon and activated carbon loaded zirconium performance. Compared with ordinary carbon, the adsorption capacity of the activated carbon loaded zirconium decreased slightly, with slower temperature rise under microwave radiation, its mass loss was decreased, and the removal rate of phenol was improved. Investigated the influence of microwave regeneration times, the activated carbon loaded zirconium has more advantages, and microwave regeneration mainly has an impact on the porous structure.Degradation mechanism studies have shown that: Firstly phenol degradated into Phenoxy and benzoquinones, then benzoquinones opened loop and formation of small carboxylic acid molecules, until totally mineralizated of CO2 and H2O, the salinity of phenol was about 65%.