Coupling few-layer MXene nanosheets with NiFe layered double hydroxide as 3D composites for the efficient removal of Cr(VI) and 1-naphthol.

• 3D flower-like few layer MXene modified NiFe-LDH (MNFL) composites were fabricated. • The added amount of MXene played a significant role in the physicochemical properties of MNFL. • MNFL-60 has excellent removal performance for both Cr(VI) and 1-naphthol. • The addition of LDH decreased the bio-toxicity of MXene. The application of few-layer MXene combined with layered double hydroxides (LDH) as adsorbent for the removal of pollutant is scarce. Herein, a series of novel flower-like MXene modified NiFe-LDH composites (MNFL) were fabricated via in situ growth of LDH on the MXene substrate. The results demonstrated that the added amount of MXene played a significant role in the physicochemical properties of MNFL. Among them, the formed MNFL-60 possessed wonderful dispersion, appreciable surface area (64.04 m2/g) and saturation magnetization (∼10 emu/g). The maximum removal capacities of MNFL-60 were highest, with the value of 372.9 mg/g for Cr(VI) and 201.8 mg/g for 1-naphthol at 288 K. Furthermore, the removal capacities of MNFL-60 for Cr(VI)/1-naphthol increased with the rise of temperature, indicating that the adsorption processes were more favorable under a higher temperature. The addition of LDH decreased the bio-toxicity of MXene, with mortality rates of more than 76 % for E. coli and 48 % for S. aureus at 100 mg/L MNFL-60 and 80 % for E. coli and 57 % for S. aureus at 200 mg/L MNFL-60. Based on the results of XPS, the removal of 1-naphthol was ascribed to the inter-reaction with N/O–containing groups, whereas the eliminate of Cr(VI) was attributed to the electrostatic attraction, complexation and partial reduction of Cr(VI) to Cr(III). Additionally, the outstanding reusability and easy recyclability could make MNFL-60 can be a promising material for remediating organic and inorganic pollutants from wastewaters. [ABSTRACT FROM AUTHOR]