Recyclable Materials as Catalysts for Nonbiodegradable Organics in Water Treatment
Scope of bimetallic and mixed oxide nanomaterials as recyclable catalysts and photocatalysts will be described for treatment of nonbiodegradable toxic organics and herbicides in water systems with special attention to the catalytic degradation of chloromethylphenol (CMP) in water facilitated by ozone using hydrotalcites Zn or Mg/VCO3 and Zn or Mg/VPO4 and wide choice of materials as heterogeneous catalysts. The catalyzed ozonation markedly accelerated the degradation of CMP. Catalyst materials were synthesized with a molar ratio of 1:0.8:0.2 and characterized using various surface characterization techniques. The influence of pH and ozone molar ratios on the percentage conversion and selectivity toward products was investigated. The reaction products were characterized by 1H NMR and LC-MS mass spectral data. Hydroxyl-3-methylfumaric acid (HMFA) and oxalic acid (OA) were the main oxidation products. Calcined catalysts gave better conversions than uncalcined. While Zn or Mg/VPO4 catalysts were efficient under acidic pH, Zn or Mg/VCO3 showed enhanced activity under alkaline conditions. In a specific case, calcined ZnVPO4 proved to be the best catalyst with 100percentage conversion, 100% dechlorination, and 30% mineralization achieved in 90 min ozone aeration time.
KeywordsChloromethylphenol Hydroxyl-3-methylfumaric acid Oxalic acid Ozonation Hydrotalicites