Compare fixed-bed reactor with fluidized-bed reactor in electrocatalytic advanced oxidation for high-concentration phenol wastewater

Abstract

High-concentration phenol wastewater poses a serious threat to the environment and humans due to its toxicity and difficulty in biodegradation. Electrocatalytic oxidation is a feasible method to solve phenol pollution. The reactor design is an important aspect of electrocatalytic oxidation. The reaction conditions were optimized in fixed-bed and fluidized-bed reactors with three-dimensional electrocatalytic oxidation. By comparing the two reactors above and optimizing the reaction conditions, a better-engineered reactor configuration can be selected to achieve higher degradation rate, more economical, and more energy-saving goals.

The optimal experimental conditions were determined by evaluating various parameters viz. initial phenol concentration, electrolyte concentration, current density in fixed-bed and aeration gas types, aeration rate, and catalysts dosage in fluidized-bed. The degradation efficiency of phenol and COD removal efficiency were 95.5 % and 92.3 % after 2 h of treatment in a fixed-bed reactor, respectively. While, they reached 99.8 % and 94.4 % after treatment 1 h in a fluidized-bed reactor, respectively. Experiments with the fixed-bed and fluidized-bed reactors were consecutively repeated 10 times to demonstrate the durability of the 1.1 % Fe-2.7 % Ce/GAC catalysts. This study compared fixed-bed and fluidized-bed reactors in the three-dimensional electrocatalytic oxidation of high-concentration phenol for the first time. The fluidized-bed demonstrated faster phenol removal, establishing it as a preferred option for scaling phenolic wastewater treatment systems.