Removal of selected pharmaceutical pollutants from groundwater using colloidal activated carbon

Groundwater (GW) is a vital source of freshwater worldwide. However, the increasing occurrence of pharmaceutical contaminants originating from various anthropogenic activities, posing significant health risks. This study investigates the efficiency of using colloidal activated carbon (CAC) in- removing carbamazepine (CBZ), lamotrigine (LTG), and caffeine (CAF) under a simulated in-situ remediation of groundwater. The study conducted through a series of fixed-bed column experiments. Several characterization techniques, including SEM/EDX, BET surface area, particle size distribution, and zeta potential, were used to identify the physiochemical properties of the CAC. Water samples spiked with a mixture of the three pharmaceutical compounds were allowed to pass through a column filled with a mixture of a bed and CAC materials. Inflow and outflow concentrations of the pharmaceuticals were measured by High-Performance Liquid Chromatography (HPLC) system. The effect of several parameters on the removal efficiency were investigated, including water flow rate, inlet concentration, CAC dosage, and bed type. SEM/EDX results revealed that CAC has a porous surface with 95.68% carbon and 4.32% potassium. The CAC has a surface area of 1112.24 m²/g, particle size ranges between 6.68 and 39.44 μm, and a negative surface charge. The optimal Dose-Response model breakthrough curve was developed at a flow rate of 1 mL/min, 2 g CAC, an initial concentration of 20 mg/L, and 50:50 sand-carbonate mixture showed a removal efficiency of around 40% of the pharmaceuticals. The study demonstrates that the use of colloidal activated carbon adsorption is a promising technology for the in-situ remediation of groundwater contaminated with pharmaceuticals.