Comparison of the Degradation and Kinetics of Tramadol Pharmaceutical in Deionized Water and Tertiary Wastewater Effluent by a Dielectric Barrier Discharge

Abstract

The discovery of pharmaceutical compounds and their associated by-products in tertiary wastewater effluent is proof that conventional techniques for wastewater treatment are ineffective in removing these micro-organic pollutants. Meanwhile, plasma technology has gained growing interest due to its ability to provide highly potent reactive oxygen species and shortwave radiations that oxidize a wide range of micro-organic compounds in water into non-toxic products. Extensive reports on plasma-based degradation of pharmaceutical compounds in synthetic mono-component water are available, but studies on the degradation of these contaminants in real samples of wastewater are rare. Therefore, this work compares the degradation of tramadol in solutions prepared with deionized water and in tertiary wastewater effluent using a Dielectric Barrier Discharge (DBD) reactor. The degradation efficiency and kinetics of the contaminant in the solution matrices were investigated. At intervals, the concentration of ozone and hydrogen peroxide in the treated solution was measured. The data from this study provide evidence for the existence of cross-interference reactions and radical scavengers which potentially impact the concentration of the reactive species available for contaminant degradation in raw water as opposed to deionized water solution. Lastly, the role of pH was examined over a wide pH range by assessing the process efficiency.