Solar heterogeneous photocatalytic degradation of phenol on TiO2/quartz and TiO2/calcite: a statistical and kinetic approach on comparative efficiencies towards a TiO2/glass system

Environ Sci Pollut Res Int. 2022 Jun;29(28):42319-42330. doi: 10.1007/s11356-022-19379-5. Epub 2022 Feb 28.

Abstract

Phenol is a widely used synthetic organic compound, which according to global estimations, is discharged into the environment at a rate of 10 tons/year through industrial waste. Phenol is a recalcitrant pollutant, and human exposure to water containing phenolic substances can lead to health issues. It has been found both in drinking water and wastewater. Solar heterogeneous photocatalytic phenol degradation, measured through chemical oxygen demand, was performed on a thin film tilted plate reactor with TiO2 immobilized onto different support materials. A full factorial experimental design (4 × 3 × 3) was carried out to statistically evaluate if the independent variables' effects were significant. Four advanced oxidation processes (photolysis, photolysis + H2O2, heterogeneous photocatalysis, and heterogeneous photocatalysis + H2O2), three support materials (quartz, calcite, and glass), and three pH levels (3, 5.4, and 9) were evaluated. Reaction kinetics were fitted to the pseudo-first-order reaction rate and data was analyzed with an ANCOVA and means test, considering solar light intensity as a covariate. Photolysis/calcite at pH 5.4 and heterogeneous photocatalysis + H2O2/glass plate at pH 3 gave the best results, with a reaction rate constant kph = 3.047 × 10-3 min-1 and kphC = 4.498 × 10-3 min-1, respectively. The three independent variables and their interactions had a significant effect in the phenol degradation (p < 0.05).

Keywords: Advanced oxidation processes; COD; Field experiment; Hydrogen peroxide; Phenol degradation; Prototype testing; Supported TiO2.

MeSH terms

  • Calcium Carbonate
  • Catalysis
  • Humans
  • Hydrogen Peroxide / chemistry
  • Kinetics
  • Phenol* / chemistry
  • Phenols / chemistry
  • Photolysis
  • Quartz
  • Titanium / chemistry
  • Water Pollutants, Chemical* / chemistry

Substances

  • Phenols
  • Water Pollutants, Chemical
  • Quartz
  • titanium dioxide
  • Phenol
  • Hydrogen Peroxide
  • Titanium
  • Calcium Carbonate