Synthesis of a novel hydrogel bead based on activated A lgerian thyme ( AATHB ) for the emerging pollutants removal

This study investigates the preparation of a novel type of hydrogel beads derived from chemically activated Algerian thyme, a plant traditionally consumed as an herbal infusion and recognized for its digestive and anti‐influenza properties. These hydrogel materials were developed for the adsorption and removal of excess diclofenac (DF) from aqueous media. The prepared activated thyme particles that were immobilized by encapsulation in sodium alginate gel were characterized by scanning electron microscopy (SEM), X‐ray scattering (XRD), nitrogen physisorption (BET), thermal study (ATG/ATD), Fourier Transform Infrared Spectroscopy (FTIR), and pH point of zero charge (pHpzc). In batch mode, the adsorption process showed pseudo‐first‐order reaction kinetics while the adsorption isotherms showed a strong correlation with the Langmuir and Temkin adsorption isotherms, thus indicating the presence of a heterogeneous surface on the prepared hydrogel beads, which contained sites with different affinities for DF. An optimal diclofenac uptake capacity of 280 mg. g −1 was obtained under pH 6, using an initial diclofenac concentration of 10 mg. L −1 , a beads dosage of 100 mg, an agitation speed of 200 rpm, and a contact time of 5 h. In continuous system on column, breakthrough profiles were obtained for a range of adsorption parameters and then exploited with the fixed bed models of Adams‐Bohart, Yoon‐Nelson and Thomas that provided an appropriate fit. Experimental data examining the influence of pH, DF initial concentration, and beads dosage were statistically evaluated using ANOVA.