Copper and Lead Adsorption of Hydroxyl-Functionalized Mo-Based MBene/Mo ₂ AlB ₂

MBene is a type of 2D metal boride compound that has drawn broad attention in the past decade. In this study, MoAlB was partially etched into a mixture of MoBene (Mo-based MBene) and Mo2AlB2. The performance in metal adsorption of the product was investigated. The large surface area (40 times higher than that of the MoAlB precursor) and −OH-functionalized surface enable MoBene/Mo2AlB2 to have excellent adsorption efficiency and capacity for Cu2+ and Pb2+ ions. An adsorption of 89.1 mg/g (93.7% of 1.5 mM CuCl2 solution) and 121.2 mg/g (39.2% of 1.5 mM PbCl2 solution) for Cu2+ and Pb2+, respectively, was observed after 15 min of contact time. The effects of the pH, contact time, adsorbent load, and initial solution concentration on adsorption capacity were investigated. The maximum adsorption capacities of Cu2+ and Pb2+ were 233.4 and 308.6 mg/g, respectively. Target metals can be observed on the adsorbent surface under SEM. The maximum adsorption of Cu2+ and Pb2+ is 140 times and 3 times higher than that of commercial activated carbon, showcasing the ability of MoBene/Mo2AlB2 to remove heavy metals from aqueous solutions.