Cu/Fe3O4@carboxylate-rich carbon composite: One-pot synthesis, characterization, adsorption and photo-Fenton catalytic activities

[Display omitted] •Cu/Fe3O4@carboxylate-rich carbon composite was prepared via a one-pot synthesis.•The composite showed the excellent adsorption and catalytic activities toward MB.•Optimal experimental conditions for the adsorption and photo-Fenton process were examined.•The possible mechanisms for the adsorption and degradation of MB were proposed.•The catalyst remained high degradation efficiency of about 90 % after five cycles. A novel Cu/Fe3O4 nanocomposite supported on carboxylate-rich carbon (Cu/Fe3O4@CRC) was successfully synthesized and characterized. The prepared composite was applied as an adsorbent and photo-Fenton-like catalyst for removal of methylene blue (MB). The results indicate that Cu/Fe3O4@CRC exhibited the highest adsorption and catalytic activities toward MB at the Fe/Cu molar ratio of 1:1 and 1:0.5, respectively. The adsorption process was thermodynamically spontaneous, endothermic, and followed well pseudo-first-order kinetic and the Freundlich isotherm models. The maximum adsorption capacity was found to be 240.27 mg g−1 at pH 7, the contact time of 40 min and temperature of 25 °C. The photo-Fenton degradation efficiency achieved 97.5 % under visible light irradiation for 40 min at optimal conditions of MB concentration of 40 mg L−1, catalyst dosage of 0.2 g L−1, pH 6.0, and H2O2 concentration of 4 mmol L−1. Besides, Cu/Fe3O4@CRC displayed a high removal efficiency and stability after five reaction cycles.