Kinetic analysis of soil contained pyrene oxidation by a pulsed discharge plasma process

A pulsed discharge plasma (PDP) reactor with net anode and net cathode was established for investigating the pyrene degradation in soil under different pulse peak voltage, air flow rate, pyrene content in soil, initial pH value and initial water content of the soil. Pyrene oxidation within the 60 min discharge time was fitting according to the pseudo-first order equation and the corresponding reaction kinetics constants (k values) were calculated. The obtained results show that pyrene oxidation under all the different reaction conditions obeyed the pseudo-first order equation well. Higher pulsed peak voltage and appropriate air flow rate were in favor of the increase of reaction rate of pyrene oxidation. A higher k value could be achieved in the lower initial pyrene content (the value was 100 mg kg⁻¹). The k value of pyrene oxidation in the case of pH=4 was 11.2 times higher than the value obtained under the condition of pH=9, while the initial water content of the soil also has a large effect on the oxidation rate of pyrene due to the effect of PDP.