Optimization, kinetics isotherm, and reusability studies of methylene blue dye adsorption using acrylic acid grafted rubber hydrogel

• Main Authors: Siti Fairus M. Yusoff,, Fazira Firdaus,, Nur Adly Ahmad Zahidi,, Nurul Huda Abdul Halim,
• Format: Article
• Language: English
• Published: Penerbit Universiti Kebangsaan Malaysia 2022
• Online Access: http://journalarticle.ukm.my/20874/1/16.pdf; http://journalarticle.ukm.my/20874/; https://www.ukm.my/jsm/malay_journals/jilid51bil10_2022/KandunganJilid51Bil10_2022.html

Hydrogel based on liquid natural rubber (LNR) crosslinked with acrylic acid (AAc) was synthesised and applied for the adsorption of methylene blue (MB) in aqueous solutions. The LNR/AAc hydrogel was prepared by free-radical polymerisation using potassium persulfate (KPS) and N,N-methylenebisacrylamide (MBA) as the initiator and the crosslinking agent, respectively. The effect of three variables (i.e., AAc:LNR weight ratio, KPS concentration and MBA concentration) on the hydrogel preparation for MB removal was further investigated using response surface methodology (RSM). A quadratic polynomial model with the analysis of variance (ANOVA) results yielding R2 value of 0.9833 was consequently obtained. The optimum conditions for the hydrogel preparation were identified as AAc:LNR weight ratio of 2.59 g/g, KPS concentration of 0.08 M and MBA concentrations of 0.08 M and resulting a high percentage of MB removal about 92.57% was obtained. Therefore, the kinetic and isotherm models of MB removal were represented by the pseudo-second order and Freundlich model, respectively, and reusability studies were also investigated resulting in the hydrogel can be used up to four cycles.