Comparison of MCPA Removal Efficiency by MIL-88A with Different Morphologies

This study focused on 2-methyl-4-chlorophenoxyacetic acid (MCPA) in agricultural wastewater as the target pollutant, synthesizing MIL-88A with three distinct morphologies (rod-like, spindle-like, and diamond-like) and systematically investigating their photocatalytic degradation performance. Characterization results demonstrated that rod-shaped MIL-88A (MIL-88A-r) exhibited the highest photocatalytic activity, achieving complete degradation of 50   mg/L MCPA within 60   min under a visible light/H 2 O 2 system, attributed to its high specific surface area (11.44   m²/g) and low photogenerated charge carrier recombination rate. Adsorption experiments revealed that the adsorption of MCPA onto the catalyst surface followed pseudo-second-order kinetics and conformed to the Langmuir isotherm model. Through response surface methodology optimization of practical wastewater treatment conditions (pH 5.7, H 2 O 2 16.3   mL/L, catalyst 1.6   g/L, irradiation time 2.5   h), COD and TOC removal rates reached 69.0% and 57.8%, respectively. Furthermore, the biodegradability of the treated wastewater was significantly enhanced. This study provides new insights into the application of MOFs materials in pesticide wastewater treatment.