Robust Adsorption and Persulfate-Based Degradation of Doxycycline by Oxygen Vacancy-Rich Copper-Iron Oxides Prepared through a Mechanochemical Route

Abstract

Persulfate-based advanced oxidation over heterogeneous catalysts is an effective approach to degrade organic pollutants, and prior adsorption of the pollutants on the catalysts is an essential step. In this study, CuO/Fe 2 O 3 (CF) composite materials with a robust adsorption capacity and catalytic activity toward organic pollutants were prepared using a green mechanochemical route. The raw CuO and α-Fe 2 O 3 present in the materials were transformed into CuFe oxide catalysts with abundant oxygen vacancies during the mechanochemical reaction. The maximum adsorption capacity of CF composite materials for doxycycline was as high as 200 mg/g. First-principles density functional theory calculations revealed that the CF composite material had a very strong ability to attract and decompose persulfate and produced more reactive oxygen species, mainly 1 O 2 , O 2 −• , and SO 4 •− . Doxycycline was decomposed into CO 2 and H 2 O through three possible pathways. The efficiency of total organic carbon (TOC) removal by the CF/persulfate system was up to 90%. Our study provided a facile synthetic method (as it involved no organic solvent, was viable for use at an industrial scale, and generated no wastewater) for the preparation of catalysts with excellent performance to decontaminate wastewater.

Ball Milling of La2O3 Tailors the Crystal Structure, Reactive Oxygen Species, and Free Radical and Non-Free Radical Photocatalytic Pathways

“…18,19 Furthermore, it can expose the internal parts of the materials and produce larger surface areas and more accessible catalytically active sites in them. 20 In one of our previous studies, for example, we showed that Co−Mn−W mixed oxides synthesized by ball milling could generate reactive oxygen species from persulfate to degrade doxycycline in wastewater. 21 In another study, CuO and Fe 2 O 3 composite materials synthesized using ball milling were shown to remove doxycycline via adsorption and persulfate activation.…”

“…21 In another study, CuO and Fe 2 O 3 composite materials synthesized using ball milling were shown to remove doxycycline via adsorption and persulfate activation. 20 MnO 2 synthesized by ball milling was also demonstrated to remove tetrabromobisphenol A in solutions better than MnO 2 produced by conventional methods. 13 Based on these previous reports, we hypothesized that ball milling could increase the oxygen vacancy on La 2 O 3 and thereby improve its photocatalytic activity to degrade emerging pollutants.…”

“…These issues could be overcome with ball milling . Ball milling enables the synthesis of highly effective metal oxide catalysts with abundant amounts of oxygen vacancies on a large scale because of its ease of application. , Furthermore, it can expose the internal parts of the materials and produce larger surface areas and more accessible catalytically active sites in them . In one of our previous studies, for example, we showed that Co–Mn–W mixed oxides synthesized by ball milling could generate reactive oxygen species from persulfate to degrade doxycycline in wastewater .…”

Photocatalytic degradation of tetracycline antibiotic and organic dyes using biogenic synthesized CuO/Fe2O3 nanocomposite: pathways and mechanism insights

“…Fresh leaves (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) from a healthy guava tree were taken and washed thoroughly with DI water. These leaves were cut into small pieces and put into a beaker containing 300 mL DI water.…”

“…CuO/Fe 2 O 3 nanocomposite have been synthesized by a few research groups and explored for various applications like oxidation of n-hexane, oxidation of carbon monoxide, degradation of organic pollutants [17][18][19][20].…”