Ultra-light and robust chitosan/polyvinyl alcohol/MXene double cross-linked aerogel efficiently adsorbs Cr(VI) and Pb(II) from wastewater for water purification.

Pollution from heavy metal wastewater poses a major threat to the natural and human environments, and the development of efficient and convenient remediation materials has become a top priority. Hence, we designed an ultra-light (0.0562 g/cm3) and robust (2.18 MPa) Chitosan/Polyvinyl alcohol/MXene double crosslinked aerogel by simple steps, and its three-dimensional porous structure endowed the aerogel with excellent compressive properties and a large number of adsorption sites for Cr(VI) and Pb(II). The adsorption process was consistent with the Langmuir adsorption isothermal model and the pseudo-second-order kinetic model, and the maximum adsorption capacities of Cr(VI) and Pb(II) were 546.9 mg/g and 473.0 mg/g, respectively. The prepared aerogels showed excellent anti-interference performance for the adsorption of target ions, and they were able to maintain the stable adsorption capacity in five cycles. The adsorption mechanism of the Chitosan/Polyvinyl alcohol/MXene aerogels was characterized by electrostatic adsorption, reduction and complexation/chelation involving O/N groups, as revealed by FTIR and XPS analyses. Eco-application assessment showed that the synthesized aerogels have excellent potential for application. In conclusion, this work provides insights for the development of heavy metal adsorbents.