Abstract
The effects of initial concentrations of PNP, doses of TiO2, cations and anions have been investigated to find out the conditions for the maximum degradation of PNP in presence of 254 nm UV light. The rate of photocatalytic degradation of PNP was increased with increasing TiO2 dose until the dose concentration reached at a value 0.4 g/100 mL. Further increase of TiO2 decreased the degradation. The maximum degradation of PNP was found with the catalyst dose 0.4 g/100 mL at pH 3. The degradation of PNP was decreased with increasing of PNP concentration. About 90% degradation of PNP was observed when 1.0 × 10﹣4 M PNP was irradiated for 2 hours in 0.4 g/100 mL of TiO2 suspension. The effect of Cu(II) and Fe(II) ions on the degradation was also investigated. Addition of Cu(II) ions enhances the percent degradation but excess of Cu(II) ions decreases the degradation. Under the same experimental conditions, the presence of and is found to be detrimental to the photodegradation of PNP. Hydrogen ion concentration of reaction mixture was found to increase continuously during photodegradation suggesting mineralization of PNP.
Highlights
Phenolic compounds discharged in effluents from petrochemicals, agrochemicals, plastic industries, preservative industries, coal distillation plants, pharmaceutical industries etc. are carcinogenic and harmful for the environment
In homogeneous system H2O2, O3 or Fentons reagents and UV radiation are used for the oxidative degradation of organics
Experiments were carried out using 100 mL of 0.5 × 10−4 M PNP solution in suspension of TiO2, the concentration of which was varied from 2 g/L to 8 g/L. pH was recorded before irradiation
Summary
Phenolic compounds discharged in effluents from petrochemicals, agrochemicals, plastic industries, preservative industries, coal distillation plants, pharmaceutical industries etc. are carcinogenic and harmful for the environment. Are carcinogenic and harmful for the environment. PNP is one of these harmful chemicals and its presence in the environment is a threat for living beings. How to cite this paper: Islam, S., et al (2014) Photocatalytic Degradation of p-Nitrophenol (PNP) in Aqueous Suspension of TiO2. Many investigations have been carried out regarding the removal of PNP from the aqueous media [1]-[3]. In homogeneous system H2O2, O3 or Fentons reagents and UV radiation are used for the oxidative degradation of organics. The process of using H2O2 under UV radiation has the advantages having low capital cost, no solid waste and no undesirable vapor emission through or after the oxidation. Semiconductor mediated-photodegradation of PNP has been investigated [4]. A number of photocatalysts such as TiO2, ZnO, Fe2O3, ZnS, WO3 and CdS are used for this purpose
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