With micropollutants in drinking water and wastewater threatening public health and ecosystems, effective water treatment is important. A novel sorptive material, a composite of carbon nanofiber (CNF) and functionalized carbon nanotubes (CNT) takes advantage of nanoscale fabrication to reduce mass transfer limitations while functionalizing the surface through wet chemical modification to target trace micropollutants. Based on our previous results, either potassium permanganate or osmium tetroxide followed with potassium permanganate were used as initial oxidants to form a higher percentage of carboxylic acids. Initially, ethylenediamine (EDA), was applied as the amine- which can also form strong interactions with metals. EDA has been successfully attached onto the carboxylated surface by using thionyl chloride or oxalyl chloride to form the acyl chloride. Though the surface functionalities are important, the surface area and pore size of the final material are also essential. Electrospun composites of the functionalized CNT with poylacrylontirile were fabricated. Of concern in pre-functionalized composite materials is the stabilization of the material at elevated temperatures and ensuring the chemical functionality is not removed. Several variations were examined, including the percentage of PAN or CNT, the use of K2CO3 as a chemical pore generator, or the use of phthalic acid or poly(methyl methacrylate) as templating pore generators. The BET surface area increased from 21.5 m2/g without CNT to 56.7 m2/g with CNT at 4:1 wt. percent, while with the addition of PMMA (4:1:4 wt. percent CNT:PAN:PMMA), the surface area increased to 123.2 m2/g. With the additional of functionalized surface sites, IR spectra and CHN elemental composition indicated that EDA was added to the surface. The EDA functionalized materials had higher binding constants with Pb2+ as indicated by less competition with an aqueous competing ligand nitrilotriacetic acid. Comparisons of composite materials at different stabilization temperatures and preparation conditions will indicate the highest surface area and ideal pore size distributions, and resilience of chemical functionalization at higher stabilizing temperatures. Sorption tests will be conducted, comparing Pb2+ sorption as one scenario of an important pollutant in tap water, followed by emerging organic micropollutants as other targeted chemical function groups are added to the surface

Composite of functionalized carbon nanotube and carbon nanofiber for improving water treatment

255th National Meeting (2018)

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