Synergy between surface adsorption and photocatalysis during degradation of humic acid on TiO2/activated carbon composites

A photocatalyst comprising nano-sized TiO2 particles on granular activated carbon (GAC) was prepared by a sol-dipping–gel process. The TiO2/GAC composite was characterized by scanning electron microscopy (SEM), X-ray diffractiometry (XRD) and nitrogen sorptometry, and its photocatalytic activity was...

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Bibliographic Details
Published in:Journal of hazardous materials 2011-02, Vol.186 (1), p.765-772
Main Authors: Xue, Gang, Liu, Huanhuan, Chen, Quanyuan, Hills, Colin, Tyrer, Mark, Innocent, Francis
Format: Article
Language:English
Subjects:
activated carbon
Adsorption
Applied sciences
Carbon - chemistry
Catalysis
Catalytic reactions
Chemical engineering
Chemistry
Degradation
Exact sciences and technology
General and physical chemistry
glass
Granular activated carbon
Humic acid
humic acids
Humic Substances
Hydrogen-Ion Concentration
Hydroxyapatite
Mathematical models
Metal Nanoparticles
Microscopy, Electron, Scanning
Nanostructure
nitrogen
Photocatalysis
Photocatalyst
Photochemistry
Pollution
quartz
Reactors
scanning electron microscopy
sorption isotherms
Surface chemistry
Surface Properties
Synergy
Temperature
Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
TiO2
Titanium - chemistry
Titanium dioxide
X-radiation
X-ray diffraction
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Summary:A photocatalyst comprising nano-sized TiO2 particles on granular activated carbon (GAC) was prepared by a sol-dipping–gel process. The TiO2/GAC composite was characterized by scanning electron microscopy (SEM), X-ray diffractiometry (XRD) and nitrogen sorptometry, and its photocatalytic activity was studied through the degradation of humic acid (HA) in a quartz glass reactor. The factors influencing photocatalysis were investigated and the GAC was found to be an ideal substrate for nano-sized TiO2 immobilization. A 99.5% removal efficiency for HA from solution was achieved at an initial concentration of 15mg/L in a period of 3h. It was found that degradation of HA on the TiO2/GAC composite was facilitated by the synergistic relationship between surface adsorption characteristics and photocatalytic potential. The fitting of experimental results with the Langmuir–Hinshelwood (L–H) model showed that the reaction rate constant and the adsorption constant values were 0.1124mg/(Lmin) and 0.3402L/mg. The latter is 1.7 times of the calculated value by fitting the adsorption equilibrium data into the Langmuir equation.
ISSN:0304-3894
1873-3336
DOI:10.1016/j.jhazmat.2010.11.063