Study of the Efficacy of Heavy Metal Ions Removal in Water Using Immobilized Titanium Dioxide

Lim, Hui Min (2019) Study of the Efficacy of Heavy Metal Ions Removal in Water Using Immobilized Titanium Dioxide. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

Text Lim Hui Min_Full Text.pdf Restricted to Registered users only Download (9MB)

Abstract

In the past few years, water pollution has become as one of the top crisis facing by living beings. Among the pollutants, heavy metals are to be concerned due to their toxic nature. The arising of TiO2 serving as both semiconductor and photo-catalyst has given a great chance in treating water through a physical adsorption of various pollutants through photo-catalytic redox processes. In this study, the ability of TiO2 to remove heavy metal ions from water through photo-catalytic reduction was investigated. By understanding the theory behind the mechanism, the matrix environments was varied chemically to see the behavior changed in both TiO2 and the heavy metal ions. This project was meant to study the removal efficiency of different heavy metal ions by immobilized TiO2. To carry out the experimental study, 500 ml of salt solution prepared from respective heavy metal ions targeted was run for the photo-catalytic reduction by the immobilized TiO2 coated on the cement block through cement-water coating method with the presence of UV radiation at with the wavelength was less than 280 nm. MP-AES was used to determine the unknown concentration of heavy metal ions remaining in the sample solution after the reaction. Throughout this study, the favorable conditions for the reaction were optimized by having 150 ppm of initial concentration of heavy metal ions to be reduced by 30 weight % of immobilized TiO2 with the stir rate at 200 rpm. The maximum removal efficiency was able to be achieved in 75 minutes at which the rate of reaction declined to ≤ 1 ppm/g TiO2/min due to decreased adsorption capacity. A neutral pH at 7 was more preferred by Cu(II) and Ni(II) to be removed whereas Pb(II) and Cd(II) preferred a higher pH of 9. On the other hand, the presence of low concentration of organic additives in the sample solution was found to have less significant effect towards the photo-catalytic reaction.