Fabrication of physically multi-crosslinked sodium alginate/carboxylated-chitosan/attapulgite-base aerogel modified by polyethyleneimine for the efficient adsorption of organic dye and Cu(II) contaminants.

The simultaneous presence of heavy metal ions and organic dyes presents significant challenges for the wastewater treatment sector. In response to this pressing issue, a novel composite aerogel has been developed: polyethyleneimine-modified sodium alginate/carboxylated chitosan/attapulgite aerogels (ATP/CCS/SA-PEI), which effectively facilitates the concurrent removal of copper ions (Cu(II)), Congo red (CR), and methylene blue (MB) from aqueous solutions. Under optimal adsorption conditions, ATP/CCS/SA-PEI exhibits superior adsorption capacities for Cu(II), MB, and CR when compared to the unmodified raw materials at equivalent dosages, achieving maximum capacities of 228.24 mg/g for Cu(II), 206 mg/g for MB, and 290.13 mg/g for CR. Additionally, the presence of coexisting ions exerts a minor adverse effect on adsorption efficiency, indicating that the synthesized ATP/CCS/SA-PEI aerogels possess commendable environmental adaptability. Characterization techniques reveal that the primary mechanisms underlying adsorption involve electrostatic interactions, hydrogen bonding, coordination complex formation, and ion exchange synergies. Simultaneously, the ATP/CCS/SA-PEI aerogel exhibits significant reusability, retaining removal efficiencies of 53 % for MB and 48 % for Cu(II) after four sorption-desorption cycles. Consequently, the synthesized ATP/CCS/SA-PEI aerogel demonstrates considerable potential for the remediation of complex pollutants in wastewater, indicating its applicability across diverse industrial sectors.