Methylene blue adsorption onto cockle shells-treated banana pith: optimization, isotherm, kinetic, and thermodynamic studies

• Main Authors: Rosalyza, Hasan, Wong, Jie Ying, Chong, Chi Cheng, Nur Farhana, Jaafar, Rohayu, Jusoh, Aishah, Abdul Jalil, Herma Dina, Setiabudi
• Format: Article
• Language: English
• Published: Department of Chemistry, Universitas Gadjah Mada Yogyakarta 2020
• Subjects: TP Chemical technology
• Online Access: http://umpir.ump.edu.my/id/eprint/30094/1/Methylene%20blue%20adsorption%20onto%20cockle%20shells-treated%20banana.pdf; http://umpir.ump.edu.my/id/eprint/30094/; https://doi.org/10.22146/ijc.42822; https://doi.org/10.22146/ijc.42822

Two low-cost wastes, banana pith (BP) and cockle shells (CS) were explored towards methylene blue (MB) removal. The performance of cockle shells-treated banana pith (CS-BP) in MB removal was compared with untreated BP and commercially Ca(OH)2-treated BP (Ca(OH)2-BP). The adsorption efficacy was following the order of BP < CS-BP < Ca(OH)2-BP, indicating the positive role of alkaline treatment towards MB removal and great potential of CS as a low-cost activation material. The optimization of MB removal onto CS-BP was executed by response surface methodology (RSM) with three independent variables (adsorbent dosage (X1), initial pH (X2) and initial MB concentration (X3)), and the optimal condition was achieved at X1 = 1.17 g/L, X2 = pH 7 and X3 = 214 mg/L, with 87.32% of predicted MB removal. The experimental data well-fitted the pseudo-second-order kinetic (R2 > 0.99) and the Langmuir isotherm (R2 = 0.999) models, demonstrating the chemisorption and naturally homogeneous process. Thermodynamics study discovered that the MB removal by CS-BP is endothermic, feasible, spontaneous and randomness growth at a solid-solute interface. It is affirmed that CS could be employed as a low-cost activation material and CS-BP as a low-cost adsorbent.