Perfluorooctanoic acid(PFOA) was one of widely used per- and poly substances(PFAS) in the industrial field and its concentration in the surface and groundwater was found with relatively high concentration compared to other PFAS. Since various processes have been introduced to remove the PFOA, adsorption using GAC is well known as a useful and effective process in water and wastewater treatment. Surface modification for GAC was carried out using Cu and Fe to enhance the adsorption capacity and four different adsorbents, such as GAC-Cu, GAC-Fe, GAC-Cu(OH)2, GAC-Fe(OH)3 were prepared and compared with GAC. According to SEM-EDS, the increase of Cu or Fe was confirmed after surface modification and higher weight was observed for Cu and Fe hydroxide(GAC-Cu(OH)2 and GAC-Fe(OH)3, respectively). BET analysis showed that the surface modification reduced specific surface area and total pore volumes. The highest removal efficiency(71.4%) was obtained in GAC-Cu which is improved by 17.9% whereas the use of Fe showed lower removal efficiency compared to GAC. PFOA removal was decreased with increase of solution pH indicating electrostatic interaction governs at low pH and its effect was decreased when the point of zero charges(pzc) was negatively increased with an increase of pH. The enhanced removal of PFOA was clearly observed in solution pH 7, confirming the Cu in the surface of GAC plays a role on the PFOA adsorption. The maximum uptake was calculated as 257 and 345 μg/g for GAC and GAC-Cu using Langmuir isotherm. 40% and 80% of removal were accomplished within 1 h and 48 h. According to R2, only the linear pseudo-second-order(pso) kinetic model showed 0.98 whereas the others obtained less than 0.870.

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are reportedly detected in public drinking water supplies. The U.S. Environmental Protection Agency (EPA) considers these compounds emerging contaminants and PFOA and PFOS were placed on EPA’s Contaminant Candidate List and health advisory levels for them in drinking water were established at 70 ppt. NSF created protocol NSF P473, which established minimum requirements for materials, design, construction and performance of drinking water treatment systems to remove PFOA and PFOS. The basic test protocol methodologies for NSF P473 are based on organic contaminant reduction protocols under NSF/ANSI Standard 53 for activated carbon systems, and on health effects contaminant reduction protocols under NSF/ANSI Standard 58 for reverse osmosis (RO) systems.