Design of separable magnetic chitosan grafted-benzaldehyde for azo dye removal via a response surface methodology: Characterization and adsorption mechanism

• Published in: International journal of biological macromolecules Vol. 242; no. Pt 4; p. 125086
• Main Authors: Arni, Laili Azmiati, Hapiz, Ahmad, Abdulhameed, Ahmed Saud, Khadiran, Tumirah, ALOthman, Zeid A., Wilson, Lee D., Jawad, Ali H.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.07.2023
• Subjects: Acid red 88 dye; Adsorption; Chitosan; Grafting; Response surface methodology; Chitosan; Acid red 88 dye; Response surface methodology; Adsorption; Grafting
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2023.125086

In this study, a magnetic chitosan grafted-benzaldehyde (CS-BD/Fe3O4) was hydrothermally prepared using benzaldehyde as a grafting agent to produce a promising adsorbent for the removal of acid red 88 (AR88) dye. The CS-BD/Fe3O4 was characterized by infrared spectroscopy, surface area analysis, scanning electron microscopy-energy dispersive X-ray, vibrating sample magnetometry, powder X-ray diffraction, CHN elemental analysis, and point of zero charge (pHPZC). The Box-Behnken design (BBD) was adopted to study the role of variables that influence AR88 dye adsorption (A: CS-BD/Fe3O4 dose (0.02–0.1 g), B: pH (4–10), and time C: (10–90 min)). The ANOVA results of the BBD model indicated that the F-value for the AR88 removal was 22.19 %, with the corresponding p-value of 0.0002. The adsorption profiles at equilibrium and dynamic conditions reveal that the Temkin model and the pseudo-first-order kinetics model provide an adequate description of the isotherm results, where the maximum adsorption capacity (qmax) with the AR88 dye was 154.1 mg/g. Several mechanisms, including electrostatic attraction, n-π interaction, π-π interaction, and hydrogen bonding, regulate the adsorption of AR88 dyes onto the CS-BD/Fe3O4 surface. As a result, this research indicates that CS-BD/Fe3O4 can be utilized as an effective and promising bio-adsorbent for azo dye removal from contaminated wastewater. •A biocomposite of magnetic chitosan grafted-benzaldehyde (CS-BD/Fe3O4) was hydrothermally synthesized.•CS-BD/Fe3O4 was applied for the highly efficient removal of acid red 88 (AR88) dye from aqueous media.•The optimal adsorption conditions of the AR88 adsorption were investigated by the RSM-BBD approach.•Temkin and pseudo-first-order models fit the dye adsorption data.•The CS-BD/Fe3O4 possesses a maximum dye adsorption capability (154.1 mg/g) for AR88.