Removal of MTBE\nand BTEX Pollutants from Contaminated\nWater Using Colloidal Activated Carbon (CAC)

Methyl tertiary-butyl ether (MTBE) and BTEX (benzene,\ntoluene,\nethylbenzene, and xylenes) are common groundwater contaminants that\npose significant health risks. This study investigated the efficiency\nof a colloidal activated carbon (CAC) material in removing MTBE and\nBTEX from contaminated water using batch and continuous core flooding\nsystems. In the batch system, a mixture of sand and carbonate was\ncoated with 1–3 g of CAC for the removal of contaminants. The\ncore flooding system was packed with similar materials and mixed with\n10 g of CAC. X-ray diffraction (XRD) revealed that the carbonate consists\nof more than 97% calcite, with traces of clay and quartz minerals.\nOn the other hand, the sandstone sample showed around 89% quartz,\n8% clay minerals, and traces of feldspar. The CAC has a surface area\nof 1050 m<sup>2</sup>/g, mean particle size of 31.8 μm, density\nof 1.0976 (g/cm<sup>3</sup>), viscosity of 24.4 mPa·s, and a\nnegative surface charge. Spiked water samples with 2000 ppb MTBE and\nBTEX concentrations ranging between 1000 and 200 ppb were injected\nthrough the system at rates of 0.5 and 1.0 mL/min. The results showed\nthat the type of packing materials and flow rate have a significant\nimpact on contaminant removal. For example, the removal efficiency\nwas higher in sandstone due to uniform particle shapes facilitating\nbetter water distribution and CAC accessibility within the pore medium.\nA lower injection rate (0.5 mL/min) resulted in higher removal efficiencies\ndue to increased contact time between contaminants and CAC. At 1 mL/min,\nthe maximum removal of 94% and 65% for MTBE and benzene was achieved\nin carbonate, while 99% and 96% were achieved in sandstone, respectively.\nAt 0.5 mL/min, complete MTBE removal and over 95% benzene removal\nwere achieved in both materials. Overall, the CAC demonstrated excellent\nMTBE and BTEX removal capabilities, exceeding 95%, offering a promising\napproach for in situ groundwater remediation.