Light Emitting Diode Based Photocatalytic Treatment of Sulfolane Contaminated Water using Nanomaterials
Date
2020-05-14
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Abstract
Sulfolane is a highly water soluble and stable compound that is used in many industries due to its excellent performance as an industrial solvent. Elevated levels of sulfolane have been detected in groundwater in Alberta due to accidental release from gas treatment plants. Stringent environmental regulatory requirements regarding sulfolane have generated a need for effective water treatment technologies for removal of sulfolane. This research investigates a photocatalytic water treatment system aimed at removing sulfolane from groundwater. In particular, degradation of sulfolane using a photoreactor fitted with light emitting diodes (LEDs) was studied. The performances of commercial TiO2 powder (P25) and reduced graphene oxide TiO2 composite (RGO-TiO2) were compared. The impact of matrix effects and type of irradiation were investigated for photocatalytic degradation of sulfolane. In addition, a reusability test was conducted for the photocatalyst to examine the degradation of sulfolane in consecutive cycles with new batches of sulfolane contaminated water. The results demonstrated that the combination of UVA-LED and P25 yields better performance than UVA-LED and RGO-TiO2 for the degradation of sulfolane. UVA-LEDs displayed more efficient use of photon energy when compared with the mercury lamps. A significant decrease in sulfolane degradation was observed in the presence of anions and co-contaminants. LED based TiO2 photocatalysis was effective in degrading sulfolane even after three photocatalytic cycles. Oxidants and nanomaterials were used to improve TiO2 based photocatalytic degradation of sulfolane. Hydrogen peroxide (H2O2), sodium persulfate (PS) and ozone (O3) were the oxidants studied and carbon nanotubes (CNT) and nanosized zero valent iron (nZVI) were used as the nanomaterials. The impact of these oxidants and nanomaterials at various dosages were evaluated in both Milli-Q water and groundwater. The results indicate that with a suitable dose of oxidants or nanomaterials, photocatalytic degradation of sulfolane in Milli-Q water can be enhanced. The addition of ozone contributed to a significant increase in sulfolane degradation rate in Milli-Q water. The experiments conducted in groundwater showed that oxidants (H2O2, PS and O3) increased the degradation of sulfolane while the nanomaterials (CNT and nZVI) impeded sulfolane degradation in groundwater.
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Keywords
Water treatment, Advanced Oxidation Processes (AOPs), Sulfolane, Groundwater Remediation, Light Emitting Diodes, Photocatalysis, Ozone, Persulfate, Graphene
Citation
Dharwadkar, S. (2020). Light Emitting Diode Based Photocatalytic Treatment of Sulfolane Contaminated Water using Nanomaterials (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.