Synthesis, Characterization, and Adsorption Study of ZIF-8/NH2 and GO@ZIF-8/NH2 for Dye Removal

• Main Author: Nur Afiqah [N.A], Kamaludin
• Format: Thesis
• Language: English; English; English
• Published: Springer Nature Link 2025
• Subjects: Q Science (General); QD Chemistry
• Online Access: http://ir.unimas.my/id/eprint/47741/; https://link.springer.com/article/10.1007/s13762-024-06250-y; 10.1007/s13762-024-06250-y

Zeolitic Imidazole Framework (ZIF-8) is a metal-organic framework known for its high porosity and large surface area, making it a promising adsorbent for pollutant removal. However, its efficiency in removing complex dye molecules is limited by the lack of specific functional groups necessary to enhance interactions with pollutants. To address this limitation, ZIF-8 was functionalized with amino groups and further modified with graphene oxide (GO) to improve its adsorption performance. This study explores the synthesis of amino-functionalized ZIF-8 (ZIF-8/NH2) and GO-modified ZIF-8/NH2 (GO@ZIF-8/NH2) using a solvothermal method, followed by extensive characterization through FTIR, FESEM-EDXS, Zeta Potential, XRD, XPS, and BET analysis. Batch adsorption experiments were conducted to evaluate the removal efficiency of methyl blue (MB) under varying conditions of pH, dye concentration, and contact time. The adsorption mechanisms were analyzed using Langmuir, Freundlich, Pseudo First Order, and Pseudo Second Order models. Results showed that ZIF-8/NH2 achieved an adsorption efficiency of 83.98% for MB under optimal conditions (160 ppm, pH 7, 90 minutes). The incorporation of GO significantly enhanced the performance, with GO@ZIF-8/NH2 achieving a removal efficiency of 90.45% at 200 ppm, pH 7, within 60 minutes. The improved performance was attributed to the increased mesoporosity, functional group availability, and stronger interactions such as hydrogen bonding, electrostatic attraction, and π-π stacking. The adsorption processes of both adsorbents were best described by the Freundlich isotherm model, indicating multilayer adsorption, and followed the pseudo second order kinetic model, suggesting chemisorption as the dominant mechanism. In conclusion, the incorporation of graphene oxide into amino functionalized ZIF-8 enhanced its physicochemical properties and adsorption efficiency, demonstrating its potential as an effective and sustainable adsorbent for dye removal in wastewater treatment applications. Keywords: Metal organic framework, ZIF-8/NH2, GO@ZIF-8/NH2, adsorption, dyes