Removal of triclosan from water by adsorption on activated carbons and photodegradation

Abstract

This work studied the application of adsorption with activated carbons (ACs) and photodegradation to reduce the concentration of triclosan (TCS) in aqueous solutions. Concerning the adsorption, the ACs (Darco, Norit, and F400) were characterized in detail, and batch experiments were applied to elucidate the effect of pH on the equilibrium. The results showed that at pH = 7, the maximum adsorption capacity of TCS onto the ACs was obtained, which was 18.5 mg g− 1 for Darco, 16.0 for Norit, and 15.5 for F400. The Diffusional kinetic model allowed an adequate interpretation of the experimental data. The effective diffusivity varied and increased along with the amount of TCS adsorbed, from 1.06 to 1.68×10− 8 cm2 s− 1. In the case of photodegradation, the removal percentage of TCS and sulfate radicals were verified. It was possible to ensure that the triclosan molecule was sensitive to UV light of 254 nm since the removal was over 80% using UV light. The removal of TCS was increased in the presence of sulfate radicals. It was possible to identify 2,4-dichlorophenol as one of the photolytic degradation products of triclosan, and it does not represent an environmental hazard at low concentrations of triclosan in water. These results confirm that the wastewater treatment methods proposed are effective for removing TCS from water, reaching levels of concentration that do not constitute a risk to human health or environmental hazard. Both methods effectively eliminate the pollutant with relatively easy techniques to implement.

Pulsed-Bed Column Adsorption for Triclosan Removal Using Macadamia Nut Shell Activated Carbon

“…Photodegradation and oxidation can generate harmful by-products [4][5][6]8]. Adsorption has emerged as a promising alternative for TCS removal, offering the advantage of producing non-toxic by-products [9,10]. Activated carbon is a widely favored adsorbent due to its exceptional capacity, but it generates higher production costs.…”