Fabrication of g-C₃N₄-activated ZIF-67 alginate composite hydrogel beads adsorbent for efficient organic pollutant removal: Kinetic and thermodynamic insights.

This research work presents new composite hydrogel beads adsorbent designed to adsorb brilliant green (BG) dye from water. The Graphitic carbon nitride (g-C3N4) was modified with ZIF-67 and further integrated into sodium alginate to prepared composite hydrogel beads (CHB) adsorbent. The (CHB) adsorbent were comprehensively characterized using a suite of analytical techniques, such as FT-IR, TGA, SEM, EDX, XPS and BET analysis. To determine the optimal conditions for brilliant green dye removal, batch trials were carried out across a range of pH values (2-11), Dose (0.005-0.04 g), BG dye concentrations (25-300 mg/L), time (15-300 min), and temperatures (25-40 °C) studies respectively. The BET study showed that the surface area of (CHB) adsorbent was 0.500 m2/g. The (CHB) adsorbent demonstrated a maximum adsorption capacity of 226.27 mg/g. Kinetic analysis indicated that the (CHB) adsorbent followed second-order kinetics. The isotherm study indicated that the Freundlich model provided the best fit for the equilibrium data. The removal of BG using CHB adsorbent indicated that ΔGᴼ ranged from -2.22 to -2.37 KJ/mol. However, the ΔHᴼ received results was 3.91 KJ/mol. The determination indicating the adsorption process was endothermic and takes place spontaneously has been verified by the thermodynamic study. The results from the regeneration experiments indicated that the BG dye adsorption successfully completed up to five adsorption-desorption cycles while retaining an efficiency of 82.7% throughout the entire process. This (CHB) adsorbent providing an efficient and environmentally friendly for wastewater treatment.