Formulation and optimization of a novel TiO2/calcium alginate floating photocatalyst.

Formulation and optimization of a novel TiO2/calcium alginate floating photocatalyst.
Int J Biol Macromol. 2019 Jul 04;:
Authors: Dalponte I, de Sousa BC, Mathias AL, Jorge RMM
Abstract
For the first time, TiO2 immobilized in alginate polymer was modified to turn it into a buoyant photocatalyst for achieving both higher radiance utilization efficiency and easier post-treatment separation. In this work, the low-density TiO2 alginate-based photocatalyst was synthesized by ionotropic gelation using a gas-forming agent (CaCO3, NaHCO3) in an acid medium (CH3COOH). The TiO2, CaCO3, and CH3COOH concentrations affect buoyancy, and the best response (100% of floating beads) after 24 h was determined using a central composite rotatable design combined with the response surface methodology. It was found that the optimal TiO2/CaAlg formulation were the following concentrations: 1.1 wt% TiO2, 2.3 wt% CaCO3, and 6.4 vt% CH3COOH. The resulting floating beads were uniform (size: 3.4 ± 0.4 mm, density: 0.9215 g/cm3), with a rough surface and porous internal structure, as observed in the characterizations using SEM/EDX, TGA, XRD, and FT-IR. The photocatalytic activity under UV irradiation (125 W, 254 nm) was evaluated for tartrazine dye removal, achieving up to 89% discoloration upon the first use with TOC removal capacity even after seven use cycles. This easily recoverable floating photocatalyst may be applied to improve the photo...

Source: International Journal of Biological Macromolecules - July 3, 2019 Category: Biochemistry Authors: Dalponte I, de Sousa BC, Mathias AL, Jorge RMM Tags: Int J Biol Macromol Source Type: research