Study adsorbents based on bent-Al13-CS-CTA and its application to the removal of CR from wastewater

Abstract

For rapid and efficient removal of Congo red (CR) from aqueous solutions, a composite of bent-Al₁₃-CS-CTA was prepared from bentonite (bent), chitosan (CS), citric acid (CTA) and Al₁₃ compounds. To comprehend the adsorption process, adsorption variables were changed, including initial pH of the solution, contact time, temperature, initial CR concentration, and adsorption dose. Bent intercalated with X-ray diffraction (XRD), specific surface area (BET), scanning electron microscopy (SEM) and Fourier transform infrared spectrophotometry (FTIR) were used to analyze the material. Physicochemical and structural analysis proven the incorporation of Al₁₃, CS, and CTA into the bent matrix. The pseudo-second-order model aligns with the adsorption kinetics. The adsorption isotherm conformed to the Langmuir adsorption isotherm, with a maximum adsorption capacity of 476.8 mg g⁻¹ at pH 9, a dosage of 2 g L⁻¹, and a temperature of 25 °C. Upon examining the thermodynamic properties of ΔS, ΔH, and ΔG, it was found that the reaction is a spontaneous endothermic process that could potentially be utilized to eliminate CR.