Overview
ISO 10678:2010 specifies a standardized laboratory method to determine the photocatalytic activity of surfaces (particularly fine/advanced ceramics and coatings) by measuring the degradation of the dye methylene blue (MB) in an aqueous medium under artificial UV-A irradiation. The method quantifies a surface’s ability to photochemically degrade dissolved organic molecules and is applicable to evaluation of photocatalytic self‑cleaning coatings. It explicitly excludes characterization of visible-light photoactivity, gaseous-phase degradation, direct soiling, and antimicrobial photoactivity.
Key topics and technical requirements
- Test principle: MB decolourization in contact with a potentially photoactive surface under UV-A (320–400 nm) and monitoring of dye concentration by UV/vis spectroscopy (absorbance at ~664 ± 5 nm).
- Quantities reported:
- Specific photocatalytic activity (P_MB) - expressed in mol/(m²·h)
- Photonic efficiency (ζ_MB) - percentage of incident photons leading to MB decolourization
- Typical test conditions and controls:
- Test MB concentration: 10 ± 0.5 µmol/L (conditioning solution often 20 ± 1 µmol/L)
- UV irradiance: primary condition 10 ± 0.5 W/m²; if ζ_MB > 0.10% a lower irradiance 2.5 ± 0.13 W/m² is also used
- Test duration: up to 3 h (or until full decolourization) with regular absorbance measurements (≤ 20 min intervals)
- Temperature control: 23 ± 2 °C during measurement; stirring or mixing to maintain homogeneity
- Apparatus & calibration: UV/vis spectrophotometer, UV radiometer matched to the light source, UV‑transparent cover glass, and low‑adsorption materials for sample contact; equipment must be calibrated and spectrophotometer set for the defined wavelength range.
- Sample preparation: cleaning per manufacturer, UV pre‑illumination (24–72 h) and conditioning in MB solution for ≥ 12 h in the dark; use of reference (dark) measurement for comparison.
Practical applications and users
This standard is used to:
- Evaluate and compare photocatalytic performance of ceramic surfaces and surface coatings (self‑cleaning, pollutant degradation in aqueous systems).
- Generate reproducible laboratory data for product development, quality control, and comparative claims.
Primary users:
- Materials scientists and R&D labs developing photocatalytic ceramics or coatings
- Quality assurance teams in advanced ceramics and surface-coating industries
- Testing and certification laboratories assessing photocatalytic self‑cleaning performance
Related standards
- Prepared by ISO/TC 206 (Fine ceramics). For comprehensive conformity, users often consult other ISO/TC 206 documents on fine-ceramic testing and material characterization; consult ISO cataloguing for directly related test methods.
