Simultaneous removal of volatile organic compounds from cooking oil fumes by using gas-phase ozonation over Fe(OH)₃ nanoparticles

The ozonation technology is widely used for treating indoor air pollution. This technology was developed using Fe(OH)₃ as a catalyst for the vapor-phase removal of volatile organic compounds (VOCs) from cooking oil fumes (COF). The nanocrystalline Fe(OH)₃ was prepared in an acidic environment in the presence of chloride ions. The hydroxylation of salicylic acid through catalytic ozonation indicated that the average molar ratio of hydroxyl radical:ozone was 0.67-0.69. The adsorption and oxidation by ozone showed that the nondissociated species on the catalyst surface reflected the reactivity of COF with respect to the hydroxyl radicals. The catalytic selectivity of Fe(OH)₃ was altered with the amount of hydroxyl radicals. Long-term testing for 300 h at 190 C proved the thermal stability of Fe(OH)₃, with a mean removal efficiency of VOCs of up to 95%. The retention time was as short as 0.05 s. The residual ozone concentrations were stable at less than 0.01 ppm.