A Study Toward Device Development For Nano-Enabled Microwave Water Treatment

In the United States, while regulations for clean water exist, many community-based water systems frequently violate standards for water quality. Of these violations, a large component arises from coliform bacteria. Existing treatment methods suffer from high monetary cost, long bacterial inactivation time, low equipment availability, and/or generation of byproducts in bacterial inactivation. In this study, microwave irradiation of carbon nanotubes will be harnessed for a low-cost, convenient bacterial inactivation method for water treatment. The device developed harnesses conventional microwave ovens’ high market penetration, even among lower income strata, and carbon nanotubes’ exceptional mechanical, electronic, and thermal properties. Microwave irradiation of carbon nanotubes allows for rapid, uniform heating, which holds promise for rapid bacterial inactivation. A plaster of Paris and cement matrix was formed using sugar as a pore-forming agent; varying quantities of multi-wall carbon nanotubes of varying oxidation levels were incorporated in the device preparation. The heating response for each treatment in 1 mL of water was observed for microwave irradiation ranging from 30 s to 3 min and 30 s, in intervals of 30 s. Results demonstrate incorporation of multi-wall carbon nanotubes provide a rapid heating response at 5% of device weight. Pristine MWCNTs have a more rapid heating behavior and higher temperature achieved than other treatments, suggesting that defects and functionalization have a negative impact on the heating behavior. Nonetheless, all treatments appear to plateau, implying that saturation of the MWCNTs’ heating abilities can occur. These initial results are promising, but much work remains in optimizing and verifying device characteristics.