Surface Engineering of Electrified MXene Filter for Enhanced Phosphate Removal

Abstract

The discharge of wastewater contaminated with low concentrations of phosphate can have serious consequences, including environmentally disastrous blooms of algae and harmful concentrations of phosphate in public water sources. Herein, we demonstrate an electrofiltration system with a flow-through configuration that uses an electrified hydroxyl-terminated Ti 3 C 2 T x MXene (h-Ti 3 C 2 T x ) filter to achieve near complete removal of ultralow concentration phosphate (5 mg P/L). Increasing either the applied voltage or the flow rate increases the phosphate sorption kinetics of the electrified h-Ti 3 C 2 T x filter. With a 6 mL/min recirculating flow rate, the h-Ti 3 C 2 T x filter exhibits a sorption kinetics of 1.97 h −1 and sorption capacity of 91.8 mg P/g, which was 2.6-and 4.3-fold higher than that of a pristine Ti 3 C 2 T x filter, respectively. The enhanced electrofiltration kinetics and capacities are attributed to the synergistic effects of plentiful sites for sorption, electrochemical enhancement, and flow-through design. The mechanism for phosphate sorption combined interlayer diffusion with surface complexation at the outer level in terms of electrostatic attraction and at the inner level in terms of Ti−O−P interactions. Overall, our research elucidates the utilization of a flow-through electrified filter incorporating −OH groups that can boost the sorption kinetics and capacity for phosphate, offering a promising paradigm for efficient water purification.

Efficient Homolytic Cleavage of H2O2 on Hydroxyl‐Enriched Spinel CuFe2O4 with Dual Lewis Acid Sites

“…This is because OH − could interfere with the formation of hydrogen bonds between hydroxyl‐rich surfaces and O atoms in H 2 O 2 . On the contrary, the increase of pH promotes the RhB elimination when the hydroxyl density of CuFe 2 O 4 is poor (Figure S22), which results from that OH − can efficiently compensate the hydroxyl groups on metal sites to assemble dual Lewis acid sites [25] . These results indicate that there is a synergistic effect between the dual Lewis acid sites in CuFe 2 O 4 , and the bridging hydroxyls could assist tetrahedral Cu 2+ sites for efficient homolytic cleavage of H 2 O 2 .…”