ISO 4907-3:2023

Overview

ISO 4907-3:2023 - Plastics - Ion exchange resin - Part 3 specifies laboratory test methods to determine the exchange capacity of styrene anion exchange resins in hydroxide form. The standard covers procedures to measure the total exchange capacity, the strong‑base group capacity, and the weak‑base group capacity. It describes sampling, sample preparation, reagents, apparatus, titration procedures and calculation/reporting requirements used to assess resin active-site content and condition.

Key topics and requirements

• Scope and principle
  • Focus on styrene anion exchange resins converted to hydroxide form. Exchange capacity is measured by ion exchange with strong acid (e.g., HCl) or neutral salts (e.g., Na2SO4) followed by titration.
• Sampling and sample preparation
  • Representative sampling per Annex A; backwash and pretreat resin in an exchange column to specified expansion and wash conditions.
• Reagents and apparatus
  • Specifies analytical-grade reagents (water to ISO 3696), standard solutions (e.g., 0.1 mol/L HCl and NaOH), 2 mol/L NaOH, 0.5 mol/L Na2SO4, indicators and an exchange column and water bath.
• Test procedures
  • Total exchange capacity: example procedure uses 2.0 g sample, 100 mL 0.1 mol/L HCl, 40 °C soak ≥2 h, then titration of aliquot with 0.1 mol/L NaOH (phenolphthalein endpoint).
  • Strong‑base group capacity: examples use 2.0 g (strong‑base resins) or 10.0 g (weak‑base resins), 100 mL Na2SO4 soaking, then titration with 0.1 mol/L HCl (mixed indicator).
• Calculations and reporting
  • Standard gives formulas for converting titration volumes to capacity (mmol/g or mol/L), plus required test-report items and conditions.
• Safety and quality
  • Warnings about hazardous reagents and recommendation to standardize/validate titrant concentrations regularly.

Applications

• Quality control and acceptance testing of anion exchange resins during manufacture, shipment and receipt.
• Performance assessment for water treatment, deionization, chromatography and industrial separations where anion exchange functionality determines process efficiency.
• Degradation and contamination monitoring - comparing strong‑ and weak‑base group capacities helps detect resin fouling or chemical breakdown.
• Research and product development for resin formulations and regeneration methods.

Who should use this standard

• Resin manufacturers and suppliers, analytical testing laboratories, water-treatment engineers, chemical process engineers, and quality assurance teams requiring standardized, reproducible methods to quantify anion exchange performance.

Related standards

• ISO 4907-2:2023 - Determination of water content of anion exchange resins (referenced for moisture removal).
• ISO 3696 - Water for analytical laboratory use.

Keywords: ISO 4907-3:2023, ion exchange resin, anion exchange resins, hydroxide form, exchange capacity, total exchange capacity, strong-base group capacity, weak-base group capacity, titration, styrene anion exchange resins, laboratory test methods.