Advances in Hydrodechlorination Technologies for Diclofenac Removal from Aqueous Systems

Abstract

This review article describes the most recent studies carried out on the catalytic hydrodechlorination (HDC) of Diclofenac (DFC). In this context, the most commonly employed catalytic materials for the removal of DFC from aqueous matrices are reviewed, along with their main performance outcomes. Various strategies for the HDC of DFC are discussed, including conventional approaches that rely on molecular hydrogen as the electron donor, as well as emerging alternatives based on biocatalytic and electrocatalytic processes. Additionally, the optimized reaction conditions for each catalytic system are discussed, along with relevant kinetic models and mechanistic insights that contribute to a deeper understanding of the HDC of DFC. Future perspectives on the use of catalysts with alternative properties for DFC removal via HDC are also discussed, aiming to highlight potential applications in wastewater treatment and the broader field of heterogeneous catalysis.

Keywords: aqueous systems; catalysts; diclofenac; hydrodechlorination.

Figure 1

Number of documents published in the period 2011–2025 regarding the DFC HDC. (Bibliometric analysis was carried out in Web of Science by using the Keywords “Hydrodechlorination” and “Diclofenac”).

Figure 2

Proposed mechanism for the HDC of DFC over Pd-based catalysts. Adapted from Wu et. al, Wang et. al, Nieto-Sandoval et al., and De Corte et al. Reprinted with permission from Ref. [26] Copyright 2012 Elsevier. Ref. [36] Copyright 2015 Royal Society of Chemistry. Ref. [50] Copyright 2015 Taylor & Francis. Ref. [52] Copyright 2019 Elsevier.

Figure 3

Illustration of the Pd-based catalysts poisoning during HDC of real aqueous matrices by active site blocking with Cl⁻ ions. Adapted from de Pedro et al., Ordóñez et al., and Nieto-Sandoval et al. Reprinted with permission from Ref. [51] Copyright 2018 Elsevier. Ref. [52] Copyright 2019 Elsevier. Ref. [64] Copyright 2010 Elsevier. Ref. [76] Copyright 2011 Elsevier.

Figure 4

Illustration of the DFC removal by coupling Pd catalytic and microbiological processes through a H_2-based membrane biofilm reactor (Pd-MBfR). Reprinted with permission from Ref. [27]. Copyright 2022 Elsevier.