Exploring Molecular Sieve Capabilities of Activated Carbon Fibers to Reduce the Impact of NOM Preloading on Trichloroethylene Adsorption

• Published in: Environmental science & technology Vol. 40; no. 4; pp. 1321 - 1327
• Main Authors: Karanfil, Tanju, Dastgheib, Seyed A, Mauldin, Dina
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.02.2006
• Subjects: 01 COAL, LIGNITE, AND PEAT; ACTIVATED CARBON; ADSORPTION; Applied sciences; BENCH-SCALE EXPERIMENTS; Carbon; Carbon - chemistry; CARBON FIBERS; CHLORINATED ALIPHATIC HYDROCARBONS; Drinking water and swimming-pool water. Desalination; ETHYLENE; Exact sciences and technology; General purification processes; GRANULAR MATERIALS; MOLECULAR SIEVES; Pollutants; Pollution; Pore size; PORE STRUCTURE; Porosity; Sorption; SORPTIVE PROPERTIES; Trichloroethylene - chemistry; Trichloroethylene - isolation & purification; Wastewaters; Water Purification - methods; Water treatment; Water treatment and pollution; Drinking water treatment; Fibrous material; Water treatment; Organic matter; Liquid solid adsorption; Competitive reaction; Organic chlorine compounds; Mesoporosity; Molecular sieve; Organic solvent; Pore size; Microporosity; Granular material; Activated carbon; Chlorocarbon; Physicochemical purification; Adsorbent; Waste water purification; Organic compounds; Ethylene(trichloro)
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es051285o

Adsorption of trichloroethylene (TCE) by two activated carbon fibers (ACFs) and two granular activated carbons (GACs) preloaded with hydrophobic and transphilic fractions of natural organic matter (NOM) was examined. ACF10, the most microporous activated carbon used in this study, had over 90% of its pore volume in pores smaller than 10 Å. It also had the highest volume in pores 5−8 Å, which is the optimum pore size region for TCE adsorption, among the four activated carbons. Adsorption of NOM fractions by ACF10 was, in general, negligible. Therefore, ACF10, functioning as a molecular sieve during preloading, exhibited the least NOM uptake for each fraction, and subsequently the highest TCE adsorption. The other three sorbents had wider pore size distributions, including high volumes in pores larger than 10 Å, where NOM molecules can adsorb. As a result, they showed a higher degree of uptake for all NOM fractions, and subsequently lower adsorption capacities for TCE, as compared to ACF10. The results obtained in this study showed that understanding the interplay between the optimum pore size region for the adsorption of target synthetic organic contaminant (SOC) and the pore size region for the adsorption of NOM molecules is important for controlling NOM−SOC competitions. Experiments with different NOM fractions indicated that the degree of NOM loading is important in terms of preloading effects; however the way that the carbon pores are filled and loaded by different NOM fractions can be different and may create an additional negative impact on TCE adsorption.