Bentonite modified with quaternary ammonium for enhanced human serum albumin adsorption

Human Serum Albumin (HSA) is an important protein that helps regulate oncoticpressure and transport of diverse molecules. A high-performance adsorbent for the separation of albumin is strategic to improve efficiency and selectivity,which can result in a low-cost and simplified process for obtaining high-purity albumin. The present study aimed to elucidate the adsorption of HSA on modified bentonite and represent the adsorption capacity. Various characterizations confirm the modification and structural changes of bentonite after surfacemodification with dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (DTSACL). A central composite design (CCD) for the response surface methodology (RSM) was used to investigate and optimize the effect of the pH, concentration of HSA, and sorbent dosage on the adsorption. Thefindings demonstrated that electrostatic interaction and functionalization of the surface were implemented to enhance the adsorption capacity of the modified bentonite. Thermodynamic investigations indicate an exothermic adsorptionprocess and preferred ambient temperatures, while isothermal examinations confirm that monolayer adsorption was a better fit for the Langmuir model. The maximum adsorption capacity (q_e) of 430 mg /g was obtained with a desirability of 0.98 at optimized pH = 6.2,initial HSA concentration = 418.9 mg/L, and DTSACL-bentonite dosage = 30.1 mg in aqueous solution of HSA. The adsorption of HSA from real human serum samples achieved an adsorption efficiency of 79.8 % and a recovery rate of 92.5 %. High-performance liquid chromatography (HPLC) and SDS-PAGE analyses confirmed that DTSACL-bentonite exhibits high selectivity and efficiency, highlighting its potential as a promising adsorbent for the separation and purification of HSA.