Highly robust multilayer nanosheets with ultra-efficient batch adsorption and gravity-driven filtration capability for dye removal

Abstract

This study reports the removal of methylene blue dye (MB) from aqueous solutions by ultra-efficient batch adsorption and membrane filtration using novel nitrogen-doped multilayer molybdenum carbide and molybdenum oxide nanosheets (NMoC@Mo). During batch adsorption studies, a complete MB dye removal (99.8%) was achieved against considerably high dye concentration (200 ppm) in a very short duration (7 min) using 4 mg of adsorbent dose. The equilibrium studies confirmed that the adsorption data followed Langmuir adsorption isotherm with a maximum monolayer coverage adsorbent capacity of 204 mg g−1. Reusability study of the NMoC@Mo nanosheets revealed that the adsorption (96%) /desorption (90%) efficiency of the adsorbent remained very high upto five consecutive cycles. the A cost-effective gravity driven membrane filtration studies were performed without applying any external pressure. Membranes (M-10, M-40, and M-60) containing three different loadings of NMoC@Mo (10 mg, 40 mg, and 60 mg, respectively) into the polyvinyl difluoride (PVDF) doped solutions were exhibited a maximum dye removal of almost 85% achieved with M-40 membrane. Moreover, M-40 membrane exhibited improved hydrophilicity (contact angle: 79.94°), water flux (53.35 L/m2-h), and improved antifouling properties. The results supported the immense potential and economic feasibility of NMoC@Mo in MB dye removal using both adsorption and membrane filtration processes.