Carboxymethyl Chitosan/Gelatin/MXene Double-Cross-Linked Aerogel for Efficient Removal of Cr(VI) and Pb(II) from Wastewater

Human activities have led to heavy metal emissions, posing significant hazards to ecosystems and the health of human beings. Here, we synthesized an ultralight Carboxymethyl chitosan/Gelatin/MXene (CGM) aerogel with high backbone strength for the efficient elimination of Cr(VI) and Pb(II) from aqueous waste through a facile procedure. The three-dimensional pore structure not only endowed the aerogels with good compressive properties but also exposed a vast number of adsorption sites. The way the CGM aerogel adsorbed Cr(VI) and Pb(II) was consistent with both the Langmuir-type adsorption isothermal model and the pseudo-second-order kinetic model, and the maximum capacity for adsorption of Cr(VI) and Pb(II) reached 532.2 and 556.0 mg/g, respectively. The CGM aerogel exhibited good anti-interference ability and could maintain a high adsorption effect after five adsorption–desorption cycles. FTIR and XPS analyses confirmed that the adsorption mechanism of the CGM aerogel for Cr(VI) and Pb(II) involves electrostatic attraction, redox, and complexation/chelation between O/N groups and Cr(VI) and Pb(II). Eco-application assessment showed that the synthesized aerogels have a good potential for application. In conclusion, this work provides an idea for the development of synthesized adsorbents with an efficient heavy metal removal capacity.