Enhanced adsorption performance of a Cu/Ni-MXene composite for phosphate recovery and removal of Cr(VI) from aqueous solutions

초록

In the present study, a CuNiO-MX (CNM) hybrid adsorbent that demonstrates an excellent P recovery and removal of Cr(VI) was prepared through liquid self-assembly method. We investigated the effects of different molar ratios of Cu/Ni (Cu0.0083Ni0.00069O-MX, Cu0.05Ni0.025O-MX, Cu0.1Ni0.05O-MX, Cu0.2Ni0.1O-MX, and Cu0.4Ni0.2O-MX) on P and Cr(VI) removal and compared these samples with bare MXene. The adsorption performance of the CNM samples was superior than bare MXene, and the Cu0.1Ni0.05O-MX adsorbent was observed as the most effectual for P and Cr(VI) removal, with a removal rate that was ∼ 163.2 and 18 times higher for P and Cr(VI), respectively, than bare MXene. The maximum adsorption capacity for P and Cr(VI) was 66.3 mg/P-g and 321.2 mg/g, respectively, at an equilibrium time of 2 h. Cu0.1Ni0.05O-MX also exhibited very higher selectivity for both P and Cr(VI), while adsorption isotherm and kinetics analysis exhibited that the uptake of P and Cr(VI) onto Cu0.1Ni0.05O-MX fits well with Langmuir isotherm and pseudo-second-order models, respectively. Cu0.1Ni0.05O-MX demonstrated an excellent resistance to inorganic anions in natural water, and recycling and reusability tests indicated that Cu0.1Ni0.05O-MX maintained a high adsorption performance for P and Cr(VI) after five cycles. The adsorption-mechanisms for P and Cr(VI) using Cu0.1Ni0.05O-MX were also examined by XPS and FT-IR analysis, showing that the –OH groups played a key role in the removal of the two contaminants. Our findings indicate that the Cu0.1Ni0.05O-MX adsorbent holds great promise for the remedy of wastewater having P and Cr(VI).

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