Application of nanoporous silica in enzyme degradation of pollutants

Iranian researchers from Tehran University of Medical Sciences succeeded in the enzyme degradation of nitrophenol pollutants by using porous silica beads. The bead was used in order to stabilize laccase enzyme in this research, and it can be used in the purification of industrial wastewater. Nitrophenol compounds have wide applications in various medical, chemical, and poison production industries. However, they have been categorized as priority pollutants by US Environmental Protection Agency. Biological purification is one of the cost-effective and high-efficient methods for these materials. Nevertheless, the purification of wastewater by using fungi is very important. Laccase was immobilized in this research on porous silica beads with nanometric pores by using a fungi enzyme, and 2,4-dinitrophenol pollutants were eliminated afterwards. In this research, trametes versicolor laccase enzyme was immobilized on a porous silica bead with nanometric pores, which was designed in two phases. In the first phase, a batch pilot was used to stabilize laccase enzyme on the bead by using surfactants. Then, the optimum condition for the elimination of the pollutant was obtained by taking into account various parameters such as temperature, resistance time, pH value, initial concentration of the pollutant, and enzyme concentration. In the second phase, a continuous system was designed by taking into account the optimum conditions, and the pollutant entered the reactor continuously and the removal process proceeded through enzyme oxidation. Results of the research showed that resistance time had the highest effect on pollutant removal process while pH value had the lowest effect. Results of the research have been published in April 2013 in Iranian Journal of Environmental Health Science and Engineering, vol. 10, issue 1.