Synthesis of lanthanum oxide and cerium oxide and ozonation catalytic activities of p-chloronitrobenzene

To improve the efficiency of ozonation for removal of organic pollution from water, lanthanum oxide and cerium oxide were prepared as catalysts for the catalytic ozonation by hydrolysis of La(NO₃)₃·6H₂O and Ce(NO₃)₃·6H₂O, respectively. The physicochemical features including crystallite phases, crystallite size, BET surface area, total pore volume and functional groups of the catalysts were characterized by XRD, N₂ adsorption, SEM and FTIR spectrum analysis. The ozonation catalytic activities of lanthanum oxide and cerium oxide were tested by catalytic ozonation of trace p-chloronitrobenzene (pCNB) in water. The results showed that the adsorption rates of pCNB by lanthanum oxide and cerium oxide in 20 min were 6.7% and 9.9%, respectively. The removal rate of pCNB by ozone alone in the reaction for 20 min was only 37.2%. The removal rate of pCNB was significantly increased by adding lanthanum oxide as the catalyst, and the pCNB removal rate of 82.1% was obtained after the reaction for 20 min, while the pCNB removal of 24.3% was obtained after the reaction for 20 min by using cerium oxide as the catalyst.