A Comparative Study on Hexavalent Chromium Adsorption onto Chitosan and Chitosan-Based Composites

Rachid El Kaim Billah; Moonis Ali Khan; Young-Kwon Park; Amira Am; Hicham Majdoubi; Younesse Haddaji; Byong-Hun Jeon

doi:10.3390/polym13193427

A Comparative Study on Hexavalent Chromium Adsorption onto Chitosan and Chitosan-Based Composites

Polymers (Basel). 2021 Oct 6;13(19):3427. doi: 10.3390/polym13193427.

Authors

Rachid El Kaim Billah¹, Moonis Ali Khan², Young-Kwon Park³, Amira Am⁴, Hicham Majdoubi⁵, Younesse Haddaji⁵, Byong-Hun Jeon⁶

Affiliations

¹ Laboratory of Coordination and Analytical Chemistry, Department of Chemistry, Faculty of Sciences, University of Chouaib Doukkali, Avenue Jabran Khalil Jabran, El Jadida 24000, Morocco.
² Chemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
³ School of Environmental Engineering, University of Seoul, Seoul 02504, Korea.
⁴ Laboratory of Analytical Chemistry and Physico-Chemistry of Materials, Department of Chemistry, Faculty of Sciences Ben M'Sik, University of Hassan II-Casablanca, Casablanca 20000, Morocco.
⁵ Laboratory of Engineering and Materials, Department of Chemistry, Faculty of Sciences Ben M'Sik, University of Hassan II-Casablanca, Casablanca 21100, Morocco.
⁶ Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul 04763, Korea.

Abstract

Chitosan (Cs)-based composites were developed by incorporating silica (Cs-Si), and both silica and hydroxyapatite (Cs-Si-Hap), comparatively tested to sequester hexavalent (Cr(VI)) ions from water. XRD and FT-IR data affirmed the formation of Cs-Si and Cs-Si-Hap composite. Morphological images exhibits homogeneous Cs-Si surface, decorated with SiO₂ nanoparticles, while the Cs-Si-Hap surface was non-homogeneous with microstructures, having SiO₂ and Hap nanoparticles. Thermal analysis data revealed excellent thermal stability of the developed composites. Significant influence of pH, adsorbent dose, contact time, temperature, and coexisting anions on Cr(VI) adsorption onto composites was observed. Maximum Cr(VI) uptakes on Cs and developed composites were observed at pH 3. The equilibration time for Cr(VI) adsorption on Cs-Si-Hap was 10 min, comparatively better than Cs and Cs-Si. The adsorption data was fitted to pseudo-second-order kinetic and Langmuir isotherm models with respective maximum monolayer adsorption capacities (q_m) of 55.5, 64.4, and 212.8 mg/g for Cs, Cs-Si, and Cs-Si-Hap. Regeneration studies showed that composites could be used for three consecutive cycles without losing their adsorption potential.

Keywords: adsorbent regeneration; chitosan; chromium; hydroxyaptite; silica; water treatment.

Grants and funding

RSP-2021/345/Researchers Supporting Project number (RSP-2021/345), King Saud University, Riyadh, Saudi Arabia.