Activated carbon based point-of-use (POU) devices represents a billion dollar industry and are commonly used in the US by consumers to improve the quality of their tap water. These devices are good at removing taste and odor compounds and many organic compounds; however, despite some claims to the contrary, most do not have the ability to remove heavy metals such as arsenic and hexavalent chromium from tap waters. Arsenic and hexavalent chromium are found at some level in tap waters that are delivered to hundreds of millions of people in the US and in every state. The addition of nanomaterials could potentially enable the removal of arsenic and hexavalent chromium by POU devices. We will discuss in-situ impregnation techniques, the formation of nanomaterials on and within activated carbon. Ex-situ techniques, such as chemical bonding and electrostatic attachment of nanomaterials to activated carbon, will be compared to the in-situ techniques. In order to enable the POU devices to sufficiently remove arsenic and hexavalent chromium over their lifetime of use, to below regulatory limits, approximately 10% w/w or more loading of nanomaterials is required. Aside from the capacity for arsenic and hexavalent chromium removal, the stability of the attachment (minimizing leaching) and the effect of nanomaterial impregnation on performance will be considered. Additionally, the activated carbon after nanomaterial impregnation may be further processed or modified in some POU devices, the effect of this will be also considered. The parameters that we considered when testing performance of these media at bench-scale and full-scale will be described. We will conclude by comparing results for performance evaluations at varying scales with the different nanoenabled activated carbons we have developed. The developed technology can remove arsenic to below the NPDWR MCL of 10 ppb for &gt;2500 liters without significant leaching nor effects on baseline performance.

Nanoenabling activated carbon based point-of-use water filtration devices for added functionality

256th National Meeting (2018)

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