Greener Synthesis\nof Poly(LIM-<i>co</i>-DVB-<i>co</i>-AMPS): A Sustainable\nApproach to Methylene Blue Removal

A novel environmentally friendly adsorbent, poly(limonene-<i>co</i>-divinylbenzene-<i>co</i>-2-acrylamido-2-methyl-1-propanesulfonic\nacid, LIM-<i>co</i>-DVB-<i>co</i>-AMPS), was synthesized\nand applied for the adsorption of methylene blue from aqueous solutions\nin this study. The structure, morphology, and thermal stability of\nthe green adsorbent were determined by the FTIR, SEM, TGA/DTA/DTG,\nand BET techniques, ζ potential, and elemental analysis. The\nefficiency of the adsorption process was improved with respect to\nseveral experimental conditions, viz., adsorbent dose, pH, and contact\ntime. The adsorption process was found to fit very well with the Langmuir\nisotherm and the pseudo-second-order model. Benefiting from the higher\nnumber of surface sites, porous structure, and good surface area,\npoly(LIM-<i>co</i>-DVB-<i>co</i>-AMPS) particles\nexhibited a superior adsorption performance for MB with a Langmuir\nadsorption capacity of 98 mg g<sup>–1</sup>. The selectivity\nof the sorbent does not depend on the coexisting ions, and the sorbent\nis applicable in complex matrixes in the presence of these ions. The\nelution process was employed using ethanol within a 1.0 M hydrochloric\nacid (HCl) medium, leading to a remarkable usability exceeding 90%\neven after five consecutive adsorption/desorption cycles. Spike recovery\nexperiments conducted using real water samples substantiate the practical\napplicability of the adsorbent. The high efficiency, utilization of\ncost-effective materials, and ease of fabrication, coupled with their\nselective nature and lower environmental impact through sorbent reuse,\ncollectively confer superior advantages. These distinctive features\nrender the environmentally benign adsorbent highly applicable for\npromising applications in the removal of methylene blue from aqueous\nsolutions.