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Updated: Jan 30, 2026

Biofilm Removal Using Carbon Dioxide Aerosols without Nitrogen Purge
Published on: November 6, 2016
Enhanced trifluoroacetate removal from groundwater by quaternary nitrogen-grafted granular activated carbon
Hao Sun1, Fred S Cannon2, Xin He3
1School of Chemical Engineering and Technology, China University of Mining &Technology, Xuzhou 221116, Jiangsu, China; Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA 16802, United States; Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining &Technology, Xuzhou 221116, Jiangsu, China.
Abstract:
This research reports an integrated method for synthesizing a quaternary nitrogen-grafted activated carbon that is derived from a subbituminous coal source. The protocol employed nitric acid oxidation, thermal ammonia treatment and methyl iodide quaternization. The quaternized product greatly increased trifluoroacetate (TFA, CF3COO-) removal from a groundwater source. This quaternary nitrogen-grafted carbon (designated AWNQ) exhibited the highest TFA adsorption capacity of 32.9 mg/g and exhibited high energy of adsorption for TFA. Also, when processing groundwater that had been spiked with 200 ppb TFA, this quaternary nitrogen-grafted carbon removed TFA to 3 ppb breakthrough for 1860 BV, which was twelve times longer than the 150 BV for the pristine carbon. The enhanced sorption was attributed to its high quaternary nitrogen ratio (1.30, at.%), which offered 0.69 meq/g positive charge. Furthermore, high regeneration efficiency (89.5%) was achieved by the proposed regeneration protocol. The mixed regenerant (ethanol and NaCl solution) effectively stripped off the loaded TFA and regenerated the quaternary nitrogen sites. This quaternary nitrogen-grafted carbon with its fast and high uptake capacity offered technical promise for TFA removal from groundwater.
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