Functionalized Biomass Carbon-Based Adsorbent for Simultaneous Removal of Pb²⁺ and MB in Wastewater

It is of great significance to realize the sustainable development of the environment to synthesize functional materials by value-added utilization of waste resources. Herein, a composite material of polyacrylic acid/lignosulfonate sodium/cotton biochar (PAA/LS/BC) was successfully prepared by grafting polyacrylic acid with functionalized waste cotton biochar and lignosulfonate sodium. The obtained absorbent showed prominent capture ability toward Pb²⁺ and methylene blue (MB) with capture characteristics of the pseudo-second-order model and Langmuir isotherm model. This experiment explored the adsorption performance of the adsorbent for pollutants at different conditions, and further revealed the selective adsorption of Pb²⁺ and MB in the mixed system. Analysis confirmed that electrostatic attraction and complexation are the most critical methods to remove contaminants. Additionally, the regeneration and stability experiment showed that the adsorption capacity of PAA/LS/BC for pollutants did not significantly decrease after five runs of adsorption-desorption. Various results can demonstrate that the adsorbent has excellent performance for removing pollutants and can be used as a material with development potential in the field of adsorption.