SURFACE FUNCTIONALIZED ELECTRICALLY CONDUCTIVE MEMBRANE (ECM) FOR 1,4-DIOXANE REMOVAL FROM DRINKING WATER

Abstract

1,4-Dioxane is an emerging water contaminant linked with liver and kidney damage and increased cancer risk. We developed several nano-modified electrically conductive membranes (Nano-ECMs) and assessed their 1,4-Dioxane removal efficacy using a vacuum filtration system. Upon surface modifying 150 nm pore size polyvinylidene difluoride (PVDF) support membranes using diverse sizes and surface charged silver nanoparticles (NH2-AgNPs, Taxol-NH2-AgNPs, Citrate-AgNPs), or cerium dioxide nanoparticles (CeO2NPs), we tested their 1,4-Dioxane removal efficacy as a function of nanoparticle (NP) concentrations (100-400 mg/L), frequency of surface modified layers on the membrane (2-4 layers), electric potential (voltage: 0-25V), and Ultraviolet (UV254nm) irradiation (present or absent). Two glass slides surface-coated with same NPs or indium tin oxide (ITO) served as electrodes to supply potential difference to the Nano-ECM held in place by a magnetic seal. 1,4-Dioxane was quantified using the established USEPA Method 8260C-SIM. The UV + 15V + NanoECM1 (membrane/slides coated thrice with [400 mg/L CeO2NP + 400 mg/L NH2-AgNP + 100 mg/L Citrate-AgNP]); UV + 15V + NanoECM2 (membrane/slides coated twice with [100ppm Taxol-NH2-AgNPs + 100ppm Cit-AgNPs]; UV + 15V + NanoECM3 (membrane/slides coated twice with [100 ppm CeO2NP + 100ppm NH2-AgNP + 100ppm Citrate-AgNP]); and the UV + 15V + NanoECM4 (membrane/slides coated twice with 200 mg/L CeO2NP]) were the most effective Nano-ECMs with the average removal rates of 90.4%, 84.1%, 82.9%, and 78.4%, respectively, for 1,4-Dioxane removal from water samples spiked with 25mg/L 1,4-Dioxane. These results demonstrate the potential of Nano-ECM to adequately remove 1,4-Dioxane from drinking water and may be adapted in developing a low-cost, solar-powered filter module for the removal of Contaminant of Emerging Concerns (CECs) (e.g., 1,4-Dioxane, PFASs) from public water and wastewater systems and protect public health.