Recyclable Senna Obtusifolia Biochar and Cerium Metal Organic Frameworks Derived Biopolymeric Hybrid Material for Enhanced Phosphate Removal

The present work focuses on pectin (Pec) encapsulated with Senna obtusifolia leaf biochar (SBC) and cerium metal–organic frameworks (Ce-MOFs) namely, the Pec/SBC/Ce-MOFs composite developed by way of the hydrothermal method. Various techniques, including SEM, TGA, DTA, EDAX, and FT-IR, were used to analyze the physicochemical properties of the Pec/SBC/Ce-MOFs composite. Batch experiments were examined the effect of temperature, coexisting ions, contact time, and pH. The Pec/SBC/Ce-MOFs composite reached a maximum phosphate adsorption capacity of 43.00 mg/g within just 30 min. The adsorption process also affected the pH, and among coanions, sulfate had the most significant effect. Isotherm studies indicated that phosphate adsorption followed a multilayer process, aligning with the Freundlich isotherm model. Kinetic investigations found thatIntraparticle diffusion (IPD) and pseudo-second-order (PSO) models best describe the adsorption behavior. Thermodynamic analysis confirmed that phosphate adsorption on the Pec/SBC/Ce-MOFs composite was a spontaneous and endothermic way. The prepared Pec/SBC/Ce-MOFs composite was effective for up to 5 rounds, and its viability in field circumstances was assessed.