Flower-like ZnO modified TiO2@Ti3C2Tx composite for efficient adsorption of malachite green and oil-water separation

The intensification of industrial production has led to a sharp increase in the discharge of toxic organic chemicals and wastewater from printing and dyeing industry. In this study, flower-like ZnO modified TiO 2 @Ti 3 C 2 T x composites (ZnO/TiO 2 @Ti 3 C 2 T x ) were prepared by in-situ oxidation solvothermal method from zinc nitrate hexahydrate and tetramethylammonium hydroxide intercalated Ti 3 C 2 T x . During the solvothermal processes, sodium hydroxide acted as an etchant to further exfoliated the accordion-like Ti 3 C 2 T x into single or few-layer; and at the same time, TiO 2 was formed in-situ on the surface of Ti 3 C 2 T x with simultaneous deposition of flower-like ZnO. The layer structural Ti 3 C 2 T x facilitates the loading and dispersion of ZnO and TiO 2 on its surface. After the in-situ oxidation by solvothermal method, TiO 2 was evenly distributed on the surface of Ti 3 C 2 T x , adjusting the functional groups on the surface of the ZnO/TiO 2 @Ti 3 C 2 T x composite, and improving its adsorption performance. ZnO/TiO 2 @Ti 3 C 2 T x can be used as an efficient adsorbent for malachite green with a high maximum adsorption capacity of 1232.7 mg g −1 , which is higher than that of TiO 2 @Ti 3 C 2 T x (628.57 mg g −1 ). Moreover, a superhydrophilic and underwater superoleophobic ZnO/TiO 2 @Ti 3 C 2 T x @PU sponge was prepared by loading ZnO/TiO 2 @Ti 3 C 2 T x onto polyurethane (PU) sponge. The introduction of ZnO enhances the surface roughness of the ZnO/TiO 2 @Ti 3 C 2 T x @PU sponge, which can effectively separate six oil-water mixtures, and has a high separation flux of 171784 L m −2 h −1 and separation efficiency of 99.6% for cyclohexane-water mixture.