Ce/Eu redox couple functionalized HKUST-1 MOF insight to sono-photodegradation of malathion

The Ce/Eu redox pair-functionalized HKUST-1 MOF, as an innovative environmentally friendly and recyclable sono-photocatalyst, was hydrothermally mixed and fully characterized by XRD, PL, EIS, FE-SEM, EDS, Mott-Schottky, chronoamperometry, and DRS techniques. The obtained chemical and optical characteristics of the n-type Ce/Eu-HKUST-1 MOF showed that the transfer of additional 4f orbital electrons in the Ce/Eu redox pair improves the sono-photocatalytic activity. The performance of Ce/Eu-HKUST-1 MOF for the sono-photodegradation of Malathion (MA) was evaluated in the aqueous media in the simultaneous presence of blue light and ultrasonic irradiation. The optimization of the process was cross-examined using the response surface methodology as a function of the MA concentration (15-35 mg·L^-1), Ce/Eu-HKUST-1 mass (10-30 mg), pH (4-12), and ultrasonic wave irradiation duration (10-30 min). The maximum sono-photocatalytic degradation capacity was found to be 99.99% under the optimum conditions set as 25 mg·L^-1, 20 mg, 8, and 25 min for the concentration of Malathion, photocatalyst mass, pH, and irradiation duration, respectively. These findings were attributed to the suppression of electron-hole pair recombination, increased life-time of charge carriers, enhanced visible light absorption, and prominent proportion of hydroxyl and peroxide radicals formed.