Apparent Reaction Kinetics of Phenol Degradation by High-gravity Intensified Heterogeneous Catalytic Ozonation

Abstract

With spherical Fe-Mn-CuOx/γ-Al2O3 catalyst as the packing of RPB (Rotating Packed Bed), the apparent reaction kinetics of phenol degradation by high gravity intensified heterogeneous catalytic ozonation was investigated under different operating conditions (high gravity factor, pH value, liquid flow rate, temperature). The reaction rate constants in BR (Bubbling Reactor) were compared, and the apparent reaction kinetics empirical models were established. The research results showed that the direct reaction rate constant of ozone and phenol (kPhOH/O3/RPB) in the high gravity field ranges in 8.17×104~8.80×105 L·mol-1·s-1, and the indirect reaction rate constant of ·OH and phenol (kPhOH/·OH/RPB) varies in the range of 1.54×1010~1.78×1010 L·mol-1·s-1, which are higher than these for BR (kPhOH/O3/BR=1.64×104 L·mol-1·s-1, kPhOH/·OH/BR=1.05×1010 L·mol-1·s-1). The activation energy of the indirect reaction (0.53 kJ/mol) is significantly lower than that of direct reaction (34.07 kJ/mol). By linearly fitting the apparent reaction rate constants under various reaction conditions, the apparent kinetic empirical models of direct and indirect reactions were obtained. The models show that among the influencing factors, β has the greatest influence on the apparent reaction rate.

Keywords

• high-gravity technique
• heterogeneous catalysis
• ozone
• hydroxyl radicals
• phenol
• apparent reaction kinetics