Effective removal of lamotrigine using colloidal activated carbon

While granular activated carbon (GAC) exhibits strong adsorption performance for the removal of pharmaceuticals in ex-situ-controlled environments, its efficiency in the in-situ groundwater remediation is limited. Therefore, this study investigates the efficiency of using colloidal activated carbon (CAC) for the removal of lamotrigine in the lab. The adsorption performance of the CAC for lamotrigine under different operational parameters was evaluated through a series of fixed-bed columns packed with sand and CAC, mimicking a subsurface environment. Breakthrough curves were plotted, and the effect of various factors on lamotrigine removal, including flow rate, CAC dosage, inlet concentration, and background ions, was assessed. Physiochemical characterizations revealed that the CAC is negatively charged, exhibits a microporous structure with a high BET surface area of 1160 m²/g, and is rich in oxygen functional groups. The experimental breakthrough curves were fitted using various models, with the Dose-Response model being the best fit. Lamotrigine was effectively removed by the CAC with a maximum adsorption capacity of 5.76 mg. g-1 at 1 mL/min flowrate, 20 mg/L inlet concentration, 20 cm bed length and 0.6 g CAC dosage. The maximum removal efficiency of lamotrigine was 65 % at a flow rate of 0.5 mL/min. The removal efficiency was found to increase with increasing CAC dosage and decreasing both Lamotrigine initial concentrations and flow rate. The results demonstrate that CAC provides an efficient and cost-effective in-situ remediation of pharmaceutical-contaminated groundwater, at an estimated treatment cost of 13.4 $ per m³.