Application of catalytic hydrodehalogenation in drinking water treatment for organohalogenated micropollutants removal: A review

This study presents an overview on the application of catalytic hydrodehalogenation (HDH) as a potential polishing step for organohalogenated micropollutants removal during drinking water treatment. Stringent regulations for drinking water quality require the development of innovative processes to increase the efficiency of conventional Drinking Water Treatment Plants (DWTPs). Recently, HDH has appeared as a promising technology for such goal. This process can be operated under ambient conditions within a wide range of organohalogenated micropollutants concentrations, allowing to significantly decrease the toxicity of the treated water. Despite its effectiveness, the performance of the technology can be affected by the nature of the micropollutant. Pharmaceuticals, pesticides and disinfection by-products, among other, have been herein considered to evaluate the impact of the pollutant nature on the performance of the process. The impact of both the active phase and the support that constitute the catalysts commonly used in HDH has been also analyzed in detail, considering not only the commonly used precious metal-based catalysts (Pd, Rh, Pt) but also innovative and less expensive catalysts like Fe, Ni and bimetallic catalysts. Special attention has been also given to study catalyst deactivation and the development of regeneration procedures. To analyze the feasibility of the HDH treatment, its application in real complex aqueous matrices such as mineral, tap and surface water has been also considered. Furthermore, the possible integration of HDH in a conventional DWTP has been discussed, and the scaling-up of the technology using robust structured catalytic reactors has been finally addressed.