%0 Journal Article
%T Degradation of Tannic Acid Using TiO2 Nanotubes as Electrocatalyst
%A N. Lakshmi Kruthika
%A G. Bhaskar Raju
%A S. Prabhakar
%J Journal of Nanoscience
%D 2014
%R 10.1155/2014/481023
%X Structured TiO2 nanotubes were grown on 2£żmm thick titanium sheet by anodization of titanium in ethylene glycol medium containing 0.025£żM NaF. The morphology of TiO2 nanotubes (TNT) was characterized using field emission scanning electron microscope. The potential of TNT as anode and also as photocatalyst for the degradation of tannic acid was studied. The mineralization of tannic acid was measured in terms Total Organic Carbon (TOC). Only 50% of TOC could be removed by exposing the tannic acid solution to UV-radiation (photolysis), whereas it was improved to 70% by electrooxidation (EO) using TNT as anode. Maximum degradation of 83% was achieved when electrooxidation was conducted under the influence of UV-radiation (photoelectrocatalytic process (PEC)). Among the electrolytes tried, Na2SO4 was observed to be very effective for the degradation of tannic acid. The kinetics of tannic acid degradation by photoelectrocatalytic process was found to follow zero-order rate expression. 1. Introduction Recent researchers have demonstrated the treatment of wastewater containing toxic and refractory organic pollutants by electrochemical and photocatalytic methods. The photocatalytic activity of TiO2 nanoparticles for the degradation of organics was found to be encouraging [1, 2]. The TiO2 nanoparticles were also tried in various applications like hydrogen sensors [3], solar cells [4], and biocompatible materials [5]. Because of superior photocatalytic activity, the TiO2 nanofilms were also attempted for the degradation of dyes, detergents, and organic acids [6]. Since the properties of the materials vary with their microstructure, the nanotubes are expected to perform much better than the commercially available TiO2 powders. Variety of techniques such as hydrothermal, template synthesis, magnetic sputtering, and sol-gel have been tried for the synthesis of nanoscaled TiO2 wires, dots, particulates, and tubes [7]. Preparation of titanium nanotubes (TNT) by chemical precursor route fails to control the thickness and shape of the nanotubes. On the other hand, precise control over the nanotube wall thickness could be achieved by template method. The potentiostatic anodization technique was found to yield highly ordered titanium nanotubes with uniform wall thickness. The shape, wall thickness, and length of the nanotubes are easily controlled by electrolyte and applied voltage. Albu et al. [8] modified the applied voltage to prepare new bamboo type titanium nanotubes and Ji et al. [9] used alternating voltage to produce double walled titanium nanotubes. Very recently,
%U http://www.hindawi.com/journals/jns/2014/481023/