Solar-energy-enabled photocatalysis is a sustainable technology to destruct persistent environmental pollutants. Graphitic carbon nitride (g-C3N4) has emerged as a novel polymeric photocatalyst because of its response to visible light and utilization of more renewable solar energy, facile synthesis from earth abundant materials, great thermal and chemical stability, and little to none-existent toxicity; however its application in environmental remediation is largely underexplored. Here, we developed supramolecule-based g-C3N4 from melamine, cyanuric acid, and barbituric acid with significantly improved surfaced area and charge separation compared to bulk g-C3N4 only from melamine. The photocatalytic reactivity was then evaluated in batch suspensions under visible light irradiation for the removal of a model contaminant (i.e., phenol) and emerging persistent contaminants (i.e., atrazine, carbamazepine, and sulfamethoxazole) across a variety of water qualities. The optimized g-C3N4 showed a reaction rate constant of 0.02 min-1 for phenol degradation in a model buffer system under Xenon lamp irradiation (&gt; 400nm), which is 5.7 times higher than that of bulk g-C3N4 under the same experimental condition. Similarly, reactivity enhancement was also observed for the degradation of emerging pollutants. The chemistries of simulated natural water and partially treated water/wastewater had little to no inhibition on atrazine degradation kinetics compared to the model buffer system. Moreover, we performed atrazine degradation on g-C3N4 under light emitting diode (LED) irradiation to evaluate the feasibility of using artificial light sources for photocatalytic water treatment, and a comparable photocatalytic activity was achieved under LED irradiation and Xenon lamp irradiation (&gt; 400 nm). The increase of photocatalytic activity under irradiation at a shorter wavelength is in agreement with the optical absorption spectrum of g-C3N4. In summary, visible-light-responsive g-C3N4 holds great promise for the removal of waterborne persistent contaminants and the utilization of renewable solar energy, and its application will promote sustainable water treatment.

Achieving sustainable water treatment: Graphitic carbon nitride for persistent waterborne contaminant removal with visible light irradiation

251st National Meeting (2016)

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