Pharmaceuticals are rapidly accumulating in water supplies, raising health concerns. In addition, the push for global renewable energy and environmentally benign products requires the development of new technologies and materials for energy generation and environmental remediation. The capability of activated carbons generated from pistachio-nut shells to adsorb two antibiotics from water is under investigation. Such biochars result from the pyrolysis and production of syngas from of a variety of biomasses, and can be activated to increase their sorptive capacity. Three different activation methods are used: physical activation via carbon dioxide gas, and chemical activation via both phosphoric acid and potassium hydroxide treatments. All three methods yield biochars with high surface areas (between 500 and 2000 (m2)/g). The (H3PO4)-activated carbons have the widest pore size distribution, consisting of both mesopores and micropores, while the KOH- activated carbons are predominantly microporous. For physically activated biochars, we find that (CO2) activation temperature more significantly impacts surface areas than pyrolysis temperature. Batch adsorption experiments using aqueous solutions of sulfamethoxazole and oxytetracycline are being performed to assess adsorption kinetics and capacities. Using commercial activated carbon to validate the method, we find that over 95% of 60mg/L sulfamethoxazole and 90% of 30 mg/L oxytetracycline can be removed from aqueous solution using 1g/L of activated carbon. Initial analysis of adsorption data show data may be modeled by both a Freundlich and Langmuir isotherm; ongoing studies will determine specific adsorption parameters and the impact of pH and surface chemistry on sorption of these two pharmaceuticals on bio-based activated carbons.

Fabrication of bio-based activated carbons for removal of aqueous pharmaceuticals

247th National Meeting (2014)

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