Preparation, characterization, and adsorption performance of porous polyamine lignin microsphere

In this study, a porous polyamine lignin microsphere (PPALM) was prepared through the inverse suspension polymerization combined with freeze-drying, during which sodium lignosulfonate and polyetheramine (PEA) were crosslinked with epichlorohydrin (ECH) as the cross-linker. By adjusting the amount of ECH and PEA, the optimized PPALM exhibited suitable crosslinking degree, ensuring a balance of framework flexibility and rigidity, thereby facilitating the formation of abundant and fine pores. PPALM demonstrated good mechanical properties comparable to commercial sulfonated polystyrene cationic resin, with a porosity of 61.12 % and an average pore size of 283.51 nm. The saturation adsorption capacity of PPALM for Pb²⁺ was measured to be 156.82 mg/g, and it remained above 120 mg/g after five cycles of regeneration. Particularly, the concentration of 50 mg/L Pb²⁺ solution could be reduced to 0.98 mg/L after flowing through the PPALM packed bed, indicating the great potential of PPALM for application in wastewater treatment.