Photocatalytic Degradation of Sulfolane Using a LED-Based Photocatalytic Treatment System

Sulfolane is an emerging industrial pollutant detected in the environments near many oil and gas plants in North America. So far, numerous advanced oxidation processes have been investigated to treat sulfolane in aqueous media. However, there is only a few papers that discuss the degradation of sulfolane using photocatalysis. In this study, photocatalytic degradation of sulfolane using titanium dioxide (TiO2) and reduced graphene oxide TiO2 composite (RGO-TiO2) in a light-emitting diode (LED) photoreactor was investigated. The impact of different waters (ultrapure water, tap water, and groundwater) and type of irradiation (UVA-LED and mercury lamp) on photocatalytic degradation of sulfolane were also studied. In addition, a reusability test was conducted for the photocatalyst to examine the degradation of sulfolane in three consecutive cycles with new batches of sulfolane-contaminated water. The results show that LED-based photocatalysis was effective in degrading sulfolane in waters even after three photocatalytic cycles. UVA-LEDs displayed more efficient use of photon energy when compared with the mercury lamps as they have a narrow emission spectrum coinciding with the absorption of TiO2. The combination of UVA-LED and TiO2 yielded better performance than UVA-LED and RGO-TiO2 for the degradation of sulfolane. Much lower sulfolane degradation rates were observed in tap water and groundwater than ultrapure water.

Automated summary

Sulfolane, an emerging industrial pollutant, has been detected near oil and gas plants in North America. Various advanced oxidation processes have been studied for treating sulfolane, but few have discussed its degradation using photocatalysis. LED-based photocatalysis was found effective for degrading sulfolane in water, with UVA-LEDs showing more efficient use of photon energy compared to mercury lamps. The combination of UVA-LED and TiO2 exhibited better performance for sulfolane degradation than UVA-LED and RGO-TiO2.