Novel Aerogel of Aminated MXene Composite Orange Peel Biomass for Ultra-high Capacity of V(V) Adsorption

Efficient and selective adsorption of V(V), pentavalent vanadium, from strategic polymetallic shale leaching solutions is crucial for resource utilization. However, the lack of a high-capacity adsorbent poses a significant challenge. Herein, we have successfully developed a novel composite adsorbent material by cross-linking orange peel biomass with aminated MXene, referred to as OPM. The incorporation of aminated MXene enhanced the availability of reactive groups within the material. The unique aerogel structure avoids the accumulation of MXene, thus improving the exposure of active sites. Furthermore, the positively charged surface of OPM enabled efficient adsorption of pentavalent vanadium ions. Experimental results showed that the adsorption of V(V) fitted well with the Langmuir adsorption isotherm model, and its adsorption rate was controlled by the pseudo-second-order kinetic mechanism. Remarkably, OPM exhibited a remarkable maximum adsorption capacity of 748.42mg/g at pH=4. Even in the presence of interfering anions and cations, OPM maintains a high adsorption capacity for V(V).In the simulated wastewater adsorption experiment, the removal rate of V by the adsorbent exceeded 80% After five cycles of adsorption, the material retains an adsorption capacity of more than 78%. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy revealed that the adsorption mechanism of OPM on V(V) is attributed to the fact that OPM is protonated under acidic conditions and has strong electrostatic interactions with pentavalent vanadium anion, in which abundant hydroxyl and carboxyl groups can undergo ion-exchange reactions with vanadium anion. Meanwhile, the amino group reduces V(V) to V(IV) and forms a complex with the oxygen/nitrogen functional group. This study provides theoretical understanding and practical application for the synergistic adsorption of V(V) on aerogels prepared from MXene composite orange peel biomass.