Kinetic investigation of Hg (II) photoreduction using TiO2-immobilized on calcium alginate beads: Effect of ferric ion and organic compound

Jeffrey Baloyi, Tumelo Seadira, Richard Moutloali, Mpfunzeni Raphulu, Aoyi Ochieng

Research output: Contribution to conferencePaper

Abstract

To overcome the separation problems of powder TiO2, the TiO2 was immobilized on calcium alginate beads (Alg/TiO2). These synthesized beads were applied to reduce toxic Hg(II) to Hg(0) in aqueous solution under ultraviolet irradiation. In the system without Alg/TiO2 or UV light, no Hg(II) reduction was observed. The
reduction of Hg(II) was approximately 9.9 and 78% when the system was exposed to ultraviolet irradiation with blank beads and Alg/TiO2, respectively. Photoreduction of Hg(II) increased with increasing pH, initial Hg(II) concentration, catalyst dosage. Addition of Fe(III) ions and citric acid improved the photoreduction of Hg(II). The kinetic analysis of the photoreduction showed that the removal of Hg(II) best fitted with the pseudo first-order kinetic. The optimal conditions for Hg(II) photoreduction were found to be: pH 8, 2 g/L of the photocatalyst and 100 mg/L of initial Hg(II) concentration. Moreover, Alg/TiO2 can achieve 75% photoreduction activity up to the third cycles. The results show that Alg/TiO2 are promising materials to effectively treat wastewater containing Hg(II).
Original languageEnglish
Number of pages6
Publication statusPublished - 2014
Event2014 International Conference on Chemical Engineering & Advanced Computational Technologies - Pretoria, South Africa
Duration: Nov 24 2014Nov 25 2014

Conference

Conference2014 International Conference on Chemical Engineering & Advanced Computational Technologies
Abbreviated titleICCEACT’2014
CountrySouth Africa
CityPretoria
Period11/24/1411/25/14

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    Baloyi, J., Seadira, T., Moutloali, R., Raphulu, M., & Ochieng, A. (2014). Kinetic investigation of Hg (II) photoreduction using TiO2-immobilized on calcium alginate beads: Effect of ferric ion and organic compound. Paper presented at 2014 International Conference on Chemical Engineering & Advanced Computational Technologies, Pretoria, South Africa. http://iieng.org/images/proceedings_pdf/5662E1114006.pdf