ISO 10678:2024

Overview

ISO 10678:2024 specifies a standardized laboratory method to determine the photocatalytic activity of surfaces (notably fine/advanced ceramics) by measuring the degradation of methylene blue (MB) in an aqueous medium under controlled ultraviolet (320–400 nm) irradiation. The standard quantifies surface activity for degradation of dissolved organic molecules using UV exposure and reports results as specific photocatalytic activity (P_MB) and photonic efficiency (ζ_MB). It does not apply to photocatalytic characterization under visible light.

Key topics and technical requirements

• Test principle: Contact of MB testing solution with the specimen surface; irradiation through the supernatant causes decolouration that is tracked by UV/visible spectroscopy. Adsorption effects are controlled by dark/reference measurements.
• Test methods:
  • Method A - intermittently stirred test cylinders
  • Method B - continuously stirred test cells
• Measured metrics:
  • Specific degradation rate (R) - mol/(m²·h)
  • Specific photocatalytic activity (P_MB) - mol/(m²·h)
  • Photonic efficiency (ζ_MB) - % of incident photons leading to MB decolouration
• Apparatus & materials: measuring device (test cylinders or cells), low‑absorption glass pane, narrow‑band UV light source (320–400 nm) with specified irradiance (measured at specimen height), UV radiometer, photometer or UV/visible spectrometer, cuvettes, magnetic stirrer. Materials contacting MB must show low adsorption (e.g., glass, stainless steel, certain plastics).
• Calibration & evaluation: Radiometer and spectrometer calibration, preparation/conditioning of test specimens and solutions, calculation of photon irradiance and average irradiance, and procedures for result evaluation. Precision data, repeatability and reproducibility are provided (Annex C).

Practical applications and who uses this standard

• Manufacturers of fine/advanced ceramics and coated surfaces - to validate photocatalytic performance claims and guide product development.
• Independent testing and conformity laboratories - to perform repeatable, comparable photocatalytic activity tests for quality control and certification.
• R&D teams and material scientists - to compare materials, optimise photocatalytic coatings, and study UV-driven degradation mechanisms.
• Regulatory/compliance bodies and specifiers - to reference an accepted method when assessing environmental or self‑cleaning performance.

Note: While MB degradation under UV often correlates with removal of soiling, gas‑phase pollutant oxidation or antimicrobial effects, such correlations are not guaranteed-especially for surfaces with low photonic efficiency.

Related standards

• ISO 10677 - Ultraviolet light source for testing semiconducting photocatalytic materials (normative reference for ISO 10678).

Keywords: ISO 10678:2024, photocatalytic activity, methylene blue test, fine ceramics, UV photocatalysis, photonic efficiency, specific photocatalytic activity, test methods A and B, UV radiometer, ISO 10677.