Investigation of Immobilized Laccase Enzyme on Nanoporous Silica Application for Removal of 2,4-Dinitrophenol from Aqueous Solution

Background and 2, 4-dinitrophenol (2,4-DNP) is categorized as one of the priority pollutants that is used in pharmaceutical and chemical industries, pesticides, etc. In this study we aimed at investigating the biodegradation of 2,4-DNP by immobilized laccase on nano-porous silica beads.
An experimental study was conducted in which the enzyme was chemically cross-linked on the nano-porous silica beads. Temperature (40-60 ˚C), contact time (2-12 h), mediator concentration (1-3 mM), pH (4-6) and initial pollutant concentration (10-30 ppm) were considered. The high performance liquid chromatography was applied to measure the degradation of the pollutant.
The maximum removal of 2,4-DNP (91%) was achieved at T=50˚C, 2,4-DNP concentration of 10 ppm, mediator concentration of 1 mM, pH=5 and 12h contact time. ANOVA analysis showed that contact time and pH had the most and lowest effect on the process efficiency, respectively.
2,4-DNP was effectively degraded by laccase. The reusability and resistibility of the enzyme improved through immobilization. The immobilized laccase on nano-porous silica beads could be applied to remove a wide range of phenolic pollutants.