Physicochemical modification of chitosan with fly ash and tripolyphosphate for removal of reactive red 120 dye: Statistical optimization and mechanism study

• Published in: International Journal of Biological Macromolecules
• Main Author: Mohammed I.A.; Jawad A.H.; Abdulhameed A.S.; Mastuli M.S.
• Format: Article
• Language: English
• Published: Elsevier B.V. 2020
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086525292&doi=10.1016%2fj.ijbiomac.2020.06.069&partnerID=40&md5=15e1a9dad828be6ddba384357ee183c7

Chitosan (CS) was physically modified with fly ash (FA) powder and subjected to chemical cross-linking reaction with tripolyphosphate (TPP) to produce a cross-linked CS-TPP/FA composite as adsorbent for removal of reactive orange 120 (RR120) dye. Different ratios of FA such as 25% FA particles (CS-TPP/FA-25) and 50% FA particles (CS-TPP/FA-50) were loaded into the molecular structure of CS-TPP. Box–Behnken design (BBD) was applied to optimize the input variables that affected the synthesis of the adsorbent and the adsorption of RR120 dye. These variables included FA loading (A: 0–50%), adsorbent dose (B: 0.04–0.1 g), solution pH (C: 4–10), temperature (D: 30 °C–60 °C), and time (E: 30–90 min). Results revealed that the highest removal (88.8%) of RR120 dye was achieved by CS-TPP/FA-50 at adsorbent dosage of 0.07 g, solution of pH 4, temperature of 45 °C, and time of 60 min. The adsorption equilibrium was described by the Freundlich model, with 165.8 mg/g at 45 °C as the maximum adsorption capacity of CS-TPP/FA-50 for RR120 dye. This work introduces CS-TPP/FA-50 as an ideal composite adsorbent for removal of textile dyes from the aqueous environment. © 2020 Elsevier B.V.