Synthesis and Characterization of New Adsorbent Materials Obtained from Modified Thyme for Diclofenac Removal in Advanced Pharmaceutical Effluent Treatment

The purpose of this study was to evaluate the efficiency of new adsorbent material derived from thyme activated with sodium hydroxide and encapsulated with alginate at an optimal ratio. Characterization of these materials involved Fourier transform infrared spectroscopy (FTIR) and isoelectric point determination (pHpzc). Their adsorptive properties were then evaluated in batch mode for the removal of the emerging pollutant diclofenac (DC) from pharmaceutical effluent. Various parameters, including the initial pollutant concentration, solution pH, biomass quantity, and contact time, were systematically examined to gauge their impact on effectiveness. Characterization revealed the significant presence of hydroxyl (OH) and carboxylic group peaks, both integral to the adsorption process. The determined pHpzc was 8.2. Results demonstrated that the adsorption kinetics of DC onto the new adsorbent was most accurately described by the pseudo-second-order model. Under optimized conditions (pH 6, stirring rate of 150 rpm, adsorbent mass of 100 mg, and equilibrium time of 5 h), the maximum adsorption capacity reached 280 mg/g, with an efficiency of 82%. These findings underscore the practical and economic potential of utilizing thyme for the decontamination of water polluted with diclofenac.