%0 Journal Article
%A Marazuela Lamata, María Dolores
%A García Fresnadillo, David
%T An integrated photosensitizing/adsorbent material for the removal of triclosan from water samples
%D 2020
%@ 1383-5866
%U https://hdl.handle.net/20.500.14352/93093
%X Triclosan, a recalcitrant micropollutant linked to antimicrobial resistance, is not completely eliminated during wastewater treatment, reason why it has become ubiquitous, causing serious environmental problems.Photocatalytic removal of triclosan has been investigated using sunlight and a composite material consisting of tris(4,7-diphenyl-1,10 phenanthroline)ruthenium(II) chloride [Ru(dip)3]Cl2 –a singlet oxygen (1O2) photosensitizer– immobilized on poly-dimethylsiloxane (PDMS) membranes. The efficiency of triclosan photodegradation has been evaluated, as well as the influence of variables such as pH, water matrix composition and triclosan adsorption on the material. The sunlight-driven process led to an effective decrease in triclosan concentration (C0 as high as 0.35 or 1.5 mg L−1 in ultra-pure and natural water samples, respectively), with removal rates > 80% within 30 min in the presence of the photosensitizing material, while it was ≤ 50% in direct photolysis tests in the absence of the material. The improved efficiency of triclosan removal with the photosensitizing material is even more effective with the phenolic form of triclosan, which may be attributed to synergistic adsorption of the pollutant on the polymer matrix and subsequent photodegradation by 1O2. Direct photolysis is, however, the dominant pathway for the depletion of the phenolate form, although the reaction with 1O2 always increases the removal rates of the deprotonated triclosan, due to the strong electrophilic nature of this reactive oxygen species.LC-QTOF-MS screening of treated water samples did not show the presence of ions characteristic of already reported toxic triclosan phototransformation products (e.g. dioxins, dichlorophenols, etc). Moreover, these photosensitizing/adsorbent materials can be easily incorporated into solar photoreactors, allowing simple separation of the treated water. Therefore, these integrated photosensitizing/adsorbent materials may offer novel green and cost-effective options for sustainable treatment of polluted waters.
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