Title

Photocatalytic degradation of lindane using nano-tiO2 co-doped with iron and niobium prepared by sol-gel method

Date of Publication

2012

Document Type

Master's Thesis

Degree Name

Master of Science in Chemical Engineering

College

Gokongwei College of Engineering

Department/Unit

Chemical Engineering

Thesis Adviser

Susan M. Gallardo
Carl R. Estrellan
Hirofumi Hinode

Abstract/Summary

In this study, the nano-TiO2 photocatalyst co-doped with iron and niobium (Fe:Nb=1:1) for aqueous organochlorine pesticide treatment was prepared by sol-gel method. Various dopant loadings (0.05 0.1 0.3 at %) were prepared and the effects of these dopants on the physical and chemical properties of TiO2 were compared to undoped TiO2. The characteristics of co-doped photocatalysts are small crystalline size (13.4 nm 17.1 nm) the presence of absolute anatase phase low band gap energy (3.12 eV 3.18 eV) and high surface area (85.27 m2/g 97.42 m2/g). The characterization data were correlated to photocatalytic activities using lindane pesticide as a model pollutant. The photocatalytic degradation within 2 hours was done with catalyst loading of 1g/L pH of 10 and initial concentration of 1mg/L. Among them, 0.1% Fe:Nb-TiO2 photocatalyst showed the superior activity under UV (57.35% lindane removal) and visible light (53.45% lindane removal). The better efficiency of co-doped catalyst compared to that of undoped TiO2 is attributed to the cooperative effects of niobium and iron. The presence of niobium as traps of photoexcited electrons is considered to enhance the photocatalytic activity. On the other hand, iron plays an important role in reducing band gap energy resulting in the effective photo-utilization. Besides, the full factorial design was successfully applied to investigate the effect of process parameters (catalyst loading, initial pH and initial concentration) on the lindane removal under visible light. Catalyst loading, pH and its interaction show positive effects while initial concentration is negative effect on the degradation of lindane. The maximum lindane removal (61.89%) was obtained at catalyst loading of 0.7g/L pH of 11 and initial concentration of 0.5 mg/L. The first-order empirical equation is given to predict the lindane removal in design space: % Lindane removal = 129.30981 - 230.83255 * Catalyst loading - 8.20904 * pH - 11.82212 * Initial concentration + 24.61572 * Catalyst loading * pH

Abstract Format

html

Language

English

Format

Electronic

Accession Number

CDTG005311

Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

1 computer optical disc ; 4 3/4 in.

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