The Effect of pH and Aging Time on the Synthesis of TiO2 – Chitosan Nanocomposites as Photocatalyst by Sol-Gel Method at Room Temperature

Imelda Fajriati,Endang Tri Wahyuni,M Mudasir

doi:10.20884/1.jm.2017.12.2.324

Imelda Fajriati, Endang Tri Wahyuni + Show 1 more

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https://doi.org/10.20884/1.jm.2017.12.2.324

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Abstract

The synthesis of TiO2–chitosan nanocomposite photocatalyst using Titanium(IV)-Isopropoxide (TTIP) as precursors and chitosan as host material has been conducted. The synthesis was carried out using sol-gel method at room temperature and aging to grow crystal seeds and generate nanoparticles. The success of forming nano-sized anatase phase TiO2 nanocrystal was strongly influenced by the sol pH system during hydrolysis and the aging time. The effect of sol pH system and aging time to the crystallinity level and particle size were examined using X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Diffuse Reflectance UV-Spectroscopy (DR-UV). The results showed that TiO2 produced in acidic pHs (pH 2-4) tended to have higher crystallinity level than that produced in weakly alkaline (pH > 6), which prone to be amorphous. The longer aging time (> 14 days) also tended to produce the amorphous phase. Furthermore, chitosan as a host material had a notable influence in determining the crystallinity level and particle size of TiO2 in TiO2–chitosan nanocomposite.

Highlights

TiO2 nanoparticles have attracted the interest of many researchers because it can be applied widely, for instance, as photocatalyst, solar cells, gas sensors and optoelectronic devices (Chen and Mao, 2007)
In the sol-gel process, TiO2 nanoparticles are formed through hydrolysis and condensation of titanium(IV)-isopropoxide (TTIP) precursor in acetic acid solvent
TTIP is preferred as a precursor compound because the alkoxide is slower in forming TiO2 crystals than using precursor from titanium salts

Summary

Introduction

TiO2 nanoparticles have attracted the interest of many researchers because it can be applied widely, for instance, as photocatalyst, solar cells, gas sensors and optoelectronic devices (Chen and Mao, 2007). TiO2 has been applied widely for wastewater treatment because it is capable of breaking down organic compounds toxic and reduces the toxicity of heavy metals and deactivates microorganisms. TiO2 photocatalyst is nontoxic, cheap and quite stable in some conditions such as in varied pH and temperature. Photocatalytic activity of TiO2 is relatively high because of the wide band gap of energy. With the right source of light, TiO2 photocatalyst generates electron and hole pairs to start a chemical reaction chain of pollutants demineralization (Janus et al, 2011; NguyenPhan and Shin, 2011)

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