TiO2-Doped Chitosan Microspheres Supported on Cellulose Acetate Fibers for Adsorption and Photocatalytic Degradation of Methyl Orange

Chitosan/cellulose acetate (CS/CA) used as a biopolymer systema, with the addition of TiO2 as photocatalyst (C-T/CA) were fabricated by alternating electrospinning/electrospraying technology. The uniform dispersion of TiO2 and its recovery after the removal of methyl orange (MO) was achieved by incorporating TiO2 in CS electrosprayed hemispheres. The effects of pH values, contact time, and the amount of TiO2 on adsorption and photocatalytic degradation for MO of the C-T/CA were investigated in detail. When TiO2 content was 3 wt %, the highest MO removal amount for fiber membranes (C-T-3/CA) reached 98% at pH value 4 and MO concentration of 40 mg/L. According to the data analysis, the pseudo-second-order kinetic and Freundlich isotherm model were well fitted to kinetic and equilibrium data of MO removal. Especially for C-T-3/CA, the fiber membrane exhibited multiple layers of adsorption. All these results indicated that adsorption caused by electrostatic interaction and photocatalytic degradation were involved in the MO removal process. This work provides a potential method for developing a novel photocatalyst with excellent catalytic activity, adsorbing capability and recycling use.