| Abstrakt: |
This paper evaluates the photocatalytic degradation of malathion using titanium dioxide (TiO2) nanoparticles supported on sodium alginate (SA), polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP) polymer beads and ultraviolet light as irradiation source with a wavelength of 254 nm. Six different types of beads were prepared: SA, PVA, PVP, SA/TiO2, PVA/TiO2, and PVP/TiO2 to assess the effect of the adsorbent material on the photodegradation process by optimizing an experimental design using the Taguchi method. Four factors were considered: TiO2 concentration, bead mass, polymer type, and initial malathion concentration. The response variables were the percentage of removal of the contaminant and the removal rate calculated from the first-order kinetic models. A malathion degradation of 99% was achieved after 180 min of operation when using 100 g and 200 g of SA/TiO2, PVA/TiO2, and PVP/TiO2 beads. The best operating conditions were 1 g L−1 of TiO2, 100 g of bead mass, SA polymer, and 5 mg L−1 of malathion initial concentration. This study found that the adsorption process affected negatively the photodegradation process, reducing the removal efficiency and rate. Finally, the feasibility of the use of a biopolymer-enhanced photocatalytic treatment to degrade agro-industrial contaminants was demonstrated. [ABSTRACT FROM AUTHOR] |
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