A study on photodegradation of trichloroethylene using an optical fiber coated with different photocatalysts

Abstract

In this research, optical fiber photocatalytic technology was used to treat trichloroethylene (TCE) in simulated groundwater. The study investigated the effects of various conditions on TCE treatment, including the type and modification method of photocatalyst, pH value of the solution, and pollutant concentration on the photocatalytic reaction rate and hydroxyl radical conversion rate (ROH,UV). The objective was to improve the transmission and extension of light energy using the high light-conducting properties of optical fibers. This technique is particularly useful in areas where light transmission is obstructed and can address the issues associated with traditional photocatalytic treatment methods, such as photocatalyst recovery. Soil reaction flasks were used as containers, and a LED as the experimental light source. The coated photocatalysts were analyzed for their basic characteristics using SEM/EDS, UV–Vis DRS, and XRD. In addition, p-chlorobenzoic acid (pCBA) as a hydroxyl radical (･OH) probe for kinetic study and calculation of ROH,UV. The results show that N-doped TiO2 (NT) with the addition of 10 mL NH4OH improved TCE removal efficiency at sampling point A from about 20% to 49.6%, while Ag-doped TiO2 (AT) was increased to 53.8% with the addition of 0.5 g AgNO3. These two dosages had the highest hydroxyl radical generation efficiency compared to other higher dosage conditions. However, excessive dosage can inhibit crystal formation. The study also conducted reaction rates under different pH solution environments, showing that NT had the highest reaction rate (kapp) at pH 7 and AT at pH 10. Overall, this research highlights the potential of optical fiber photocatalytic technology for TCE treatment in groundwater and provides insights into the factors that affect its efficiency.