Sol-gel synthesis of composite adsorbent coating from Prosopis juliflora–activated carbon for simultaneous adsorptive removal of Cd2+ and Cr2O72- from wastewater

Abstract

To overcome the challenges associated with powdered activated carbon (PAC) in water and wastewater treatment, the efficacy of composite adsorbent coating (CAC) synthesized using a simple sol-gel method with Prosopis juliflora-activated carbon for the simultaneous reduction of Cd2+ and Cr2O72− was investigated. The CAC was characterized by FTIR (C-H, C = O, and O-H stretching), pHPZC (6 -6.6), SEM (porous-rough surface), and BET surface area (10.6 m2/g) techniques. Statistical analysis confirmed that pH and contact time significantly (p 0.99), while the metal ions removal was regulated by the PSO kinetic model (R2 > 0.999). The adsorption process was endothermic and spontaneous, as indicated by thermodynamic values (−ΔG°, +ΔH°, +ΔS°). The study demonstrates CAC's effectiveness as an alternative to PAC, offering significant advantages in removing metal ions from wastewater. HIGHLIGHTS Invasive Prosopis juliflora was utilized for composite adsorbent synthesis.; Composite was synthesized using a novel sol-gel method.; Composite adsorbent was highly stable and non-leaching.; Easy adsorbate–adsorbent separation was achieved after treatment.;

Keywords

• adsorption
• composite adsorbent coating
• isotherm
• kinetics
• prosopis juliflora
• thermodynamics