Degradation Of Benzoic Acid Under Low Temperature By Catalytic Ozonation In The Presence Of Modified Mineral Sand

Water pollution problems become increasingly serious.To meet with people's growing water quality demand,conventional water treatment process need to be upgraded.Drinking water treatment technology is bound to embark on a new level.Heterogeneous catalytic ozone oxidation technology is popular with its catalyst for easy recovery,strong oxidative treatment ability and simple process.It is hot topic to develop new and efficient catalyst and analyze its catalytic mechanism.The project attempts to establish a heterogeneous catalytic ozone oxidation technology based on microporous natural mineral materials("slag")for the removal of trace organic pollutants from water under low temperature condition.The effects of slag and its supported metal modified materials on the removal of benzoic acid from low temperature water were studied by ozone oxidation.The mechanism of catalytic oxidation was explored and analyzed.In order to improve the catalytic activity of slag,based on its load modified Ce,Co,Ti elements of the modification and the catalytic ozone oxidation to remove benzoic acid has carried on the comparison of efficiency,found that the Ce/slag has relatively better catalytic efficiency.The structure and surface properties of slag and Ce/slag were characterized by SEM,XRD,XPS and FTIR.The results show that the modification leading to the changes of the surface group,crystal structure and surface oxygen content distribution of the slag.The effects of water temperature,initial p H and t-butanol dosage on the removal of benzoic acid from catalytic system were investigated.The results showed that the catalytic system of Ce/slag was relatively small and the catalytic removal effect was more stable.Ce/slag reusability and metal dissolution evaluation results showed that the catalytic performance was relatively stable.The kinetics of ozone decomposition was analyzed.It was found that the decomposition of ozone in the system was basically followed by the(pseudo)first-order reaction kinetics model.Slag and Ce/slag can effectively promote the decomposition of ozone to produce hydroxyl radicals,while promoting the intermediate products of p-hydroxybenzoic acid production and mineralization.The results of catalytic mechanism analysis showed that Ce/slag had more surface groups and oxygen vacancies than the slag,which helps to adsorb hydroxyl radicals and benzoic acid on the surface,so as to accelerate the surface oxidation reaction and improve the removal rate of benzoic acid.Slag and its modified materials are easy to obtain,low cost in production,simple in preparation,stable in catalytic performance,etc.,it is worth to applying the project in the actual engineering.