New magnetic Schiff's base-chitosan-glyoxal/fly ash/Fe3O4 biocomposite for the removal of anionic azo dye: An optimized process

• Published in: International journal of biological macromolecules Vol. 146; pp. 530 - 539
• Main Authors: Malek, Nurul Najwa Abd, Jawad, Ali H., Abdulhameed, Ahmed Saud, Ismail, Khudzir, Hameed, B.H.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2020
• Subjects: Adsorption; Anionic azo dye; Fly ash; Magnetic chitosan; Response surface methodology; Schiff's base; Fly ash; Response surface methodology; Anionic azo dye; Adsorption; Magnetic chitosan; Schiff's base
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2020.01.020

In this study, a new magnetic Schiff's base-chitosan-glyoxal/fly ash/Fe3O4 biocomposite (Chi-Gly/FA/Fe3O4) was successfully synthesized by direct compositing of magnetic chitosan (Chi) with fly ash (FA) powder particles, and followed by Schiff's base formation via cross-linking reaction with glyoxal (Gly). Various techniques such as BET, XRD, FTIR, and SEM-EDX were utilized to characterize of Chi-Gly/FA/Fe3O4 biocomposite. The effectiveness of Chi-Gly/FA/Fe3O4 as an adsorbent was evaluated for the removal anionic azo dye such as reactive orange 16 (RO16) from aqueous environment. The effect of adsorption process parameters namely adsorbent dose (A: 0.02–0.1 g), solution pH (B: 4–10), temperature (C: 30–50 °C), and contact time (D: 5–20 min) were optimized via Box–Behnken design (BBD) in response surface methodology (RSM). The adsorption process followed the pseudo-second order (PSO) kinetic, and Freundlich isotherm models. The maximum adsorption capacity of Chi-Gly/FA/Fe3O4 biocomposite for RO16 dye was recorded to be 112.5 mg/g at 40 °C. The RO16 dye adsorption mechanism was attributed to various interactions such as electrostatic, n-π, H-bonding, and Yoshida H-bonding. Furthermore, the Chi-Gly/FA/Fe3O4 biocomposite exhibited a high ability to separate from the aqueous solution after adsorption process by external magnetic field. •A biocomposite magnetic chitosan-glyoxal/fly ash/Fe3O4 was synthesized.•The Chi-Gly/FA/Fe3O4 biocomposite was used for adsorption of reactive Orange 16 dye.•Box–Behnken design was applied to optimize the adsorption process.•The adsorption capacity for reactive orange 16 dye was 112.5 mg/g.•The adsorption isotherm followed Freundlich models.