A Laboratory Study to Assess the Use of Biochar-Based Liquid Activated Carbon for the Removal of MTBE and Benzene from Contaminated Groundwater

This laboratory-scale study investigates the capacity of using raw and Fe-impregnated biochar-based liquid activated carbon (LAC and LAC-Fe) in adsorbing Methyl Tertiary Butyl Ether (MTBE) and benzene pollutants from contaminated water. The LAC and LAC-Fe synthesized from palm residues were coated on Ottawa sand (OS), limestone (LS), and a 1:1 of OS/LS. Synthetic GAC was also used for comparison purposes. The study was carried out in laboratory-scale batch suspension adsorption tests. Distilled water samples, spiked with 2 ppm of the pollutants, were treated with LAC and LAC-Fe-coated materials. Samples were collected and analyzed for residual pollutants using gas chromatography-mass spectroscopy (GC/MS). The effect of solution pH and salinity on the removal efficiency were also investigated. Results of the study showed low removal of MTBE (<20%) by LAC and LAC-Fe coated on materials compared to GAC which achieved around 80% removal in 60 min. Slightly better removal efficiencies were obtained for benzene (∼40%) when the same materials were coated with LAC-Fe and LAC but much lower than GAC which achieved almost 96%. The study also showed that LAC-Fe had a better performance when coated on OS (∼40%), while LS coated with raw LAC showed a slightly higher removal of benzene (∼50%). Moreover, the study showed the negligible effect of pH and salinity on the removal efficiency of organic pollutants. These preliminary results indicate that more work is needed to enhance the performance of the LAC as an in-situ adsorbent for organic contaminants.