Optimization of the Adsorption Parameters of Quercetin on the Modified Montmorillonite Clay

Quercetin (QC) is a biologically active flavonoid widely investigated for cardiovascular, ocular, antiallergic, antiarthritic, and anticancer applications. In this study, montmorillonite (MMT) clay was used as a cost‐effective and environmentally friendly adsorbent for QC. To improve its surface properties and adsorption performance, MMT was modified using three surfactants from different classes: cetyltrimethylammonium bromide (CTAB) as a cationic surfactant, sodium dodecyl sulphate (SDS) as an anionic surfactant, and Triton X‐100 as a nonionic surfactant. The prepared materials were characterized by FTIR, XRD, and TGA analyses to evaluate the effect of surfactant modification on the structural and surface properties of MMT. The adsorption capacities of MMT, MMT‐CTAB, MMT‐SDS, and MMT‐Triton X‐100 were determined to be 142.386, 165.336, 145.641, and 162.589 mg/g, respectively. Surfactant modification enhanced QC adsorption, with MMT‐CTAB exhibiting the highest capacity. For MMT‐CTAB, the adsorption conditions were optimized using the Box–Behnken design, and a maximum adsorption capacity of 189.837 mg/g was obtained at pH 6.6, 55°C, and an initial QC concentration of 500 mg/L. Sequential adsorption–desorption experiments demonstrated that CTAB‐modified MMT maintained its adsorption performance over five consecutive cycles. Overall, CTAB‐modified MMT exhibited the most promising QC adsorption performance among the modified samples.