Fabrication of porous composites based on alginate to improve the adsorption capacity of Ni(II)

Calcium alginate bead (CAB) is a good adsorbent of heavy metal ions; however, CAB has a small specific surface area, limiting its applications in the removal of heavy metals in water treatment. In this study, alginate is denatured with activated carbon and surfactants to increase the porosity of the material and improve the adsorption capacity of the Ni(II) ion. Initial undenatured calcium alginate bead is almost no pores and a very small specific surface area (~0.04 m2/g). After modification, the porous composite made from alginate combined with active carbon and surfactant (P-CAB) has a large specific surface area ~160 m2/g, 4,000 times higher than CAB. The results of the Ni(II) ion adsorption study also showed that the maximum adsorption capacity of porous composite (qmax of 53.76 mg/g) significantly improved by 8.3 times than the adsorption capacity of CAB (6.48 mg/g).