A comparison of freeze- and air-dried chitosan salicylaldehyde/calcium oxide biocomposites for optimized removal of acid red 88 dye

• Published in: INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
• Main Authors: Jawad, Ali H.; Maharani, Rosika Armiyanti; Hapiz, Ahmad; Alothman, Zeid A.; Wilson, Lee D.
• Format: Article
• Language: English
• Published: ELSEVIER 2025
• Subjects: Biochemistry & Molecular Biology; Chemistry; Polymer Science
• Online Access: https://www-webofscience-com.uitm.idm.oclc.org/wos/woscc/full-record/WOS:001400437300001

Chitosan salicylaldehyde/calcium oxide nanoparticle (CS-SL/CaO) was synthesized by hydrothermal process and isolated via different drying processes, namely, air-drying (AD) and freeze-drying (FD). The physicochemical properties of freeze-dried CS-SL/CaO nanoparticle (CS-SL/CaO-FD) and air-dried CS-SL/CaO nanoparticle (CSSL/CaO-AD) were compared. In particular, the adsorption properties reveal that the specific surface area of CSSL/CaO-FD increased by ca. 6 times (BET SA = 7.28 m2/g) greater than CS-SL/CaO-FD (BET SA = 1.26 m2/g). Also, the adsorptive removal of acid red 88 dye (AR88) from aqueous media was optimized by employing the Box-Behnken design (BBD). The optimal adsorption conditions obtained from desirability functions test for the removal of AR88 dye employed a dosage of 0.09 g/100 mL of adsorbent dosage at a solution pH of 5.6 and 25 degrees C. The best AR88 dye removal was found for the adsorbents CS-SL/CaO-AD (38.2 %) and CS-SL/CaO-FD (86.1 %), which concur with differences in the adsorbent surface areas. Moreover, the adsorption kinetics and isotherm profiles for CS-SL/CaO-FD were described by the pseudo second order (PSO) and Temkin models, where the maximum adsorption capacity of AR88 by CS-SL/CaO-FD 175.4 was mg/g. These findings reveal the potential application of the CS-SL/CaO-FD towards removal of toxic cationic dye (AR88) from an aqueous environment.