Improving the adsorption capacity of Opuntia ficus-indica fruit peels by graft-copolymerization using gamma radiation

Abstract

In this work, we improved the adsorption capacity of Opuntia ficus-indica fruit peels (OFIFP) by graft-copolymerization using gamma radiation. Acrylic acid (AA) and 4-vinylpyridine (4VP) were grafted onto OFIFP to yield the adsorbents OFIFP-g-polyAA, OFIFP-g-(polyAA-co-4VP), and OFIFP-g-poly(4VP-co-AA). The viability of employing these adsorbents in the removal of textile dyes was analysed constructing adsorption isotherms for methylene blue, malachite green, methyl orange, and carminic acid. The adsorption of cationic fit Langmuir's model well, but Freundlich's model better described the adsorption of anionic dyes. Graft-copolymerization improved the adsorption capacity of OFIFW for cationic dyes by 25%. Furthermore, the removal percentage for disperse orange dye within wastewater increased by 400% using OFIFP-g-(polyAA-co-4VP). Then, graft-polymerization using gamma radiation is a suitable tool to improve the adsorption capacity of lignocellulosic adsorbents.