The ISO 11480 Pulp, paper and cardboard - Determination of total chlorine and organically bound chlorine standard, published by the International Organization for Standardization (ISO), describes two alternative methods for determining total and organically bound chlorine in pulp, paper and cardboard. These methods are applicable to all types of pulp, paper and cardboard. The lower limit for detection is approximately 20 mg/kg.
These methods are aimed at determining total and organically bound chlorine in pulp, paper, and cardboard. The microcoulometric method is based on combustion in a heated tube followed by microcoulometric titration. The Schöniger method is based on the so-called Schöniger combustion followed by ion chromatography.
The choice of procedure depends on the availability of the equipment and the risk of interference from bromine compounds in the sample. In the microcoulometric method, the result does not accurately represent the chlorine content, as it also includes some of the bromine present in the sample. Therefore, this procedure should be avoided if there is a risk of the sample having a high bromine content.
The Schöniger method involves more work than the microcoulometric method. However, since the final determination is made by ion chromatography, the result is definitively chloride. The Schöniger method also requires a larger sample size. Consequently, the obtained result is more representative. On the other hand, the microcoulometric method is faster and allows for many repeated measurements in a short time.
The microcoulometric method is based on the principle of determining, for example, the chlorine content by burning it under controlled conditions in a quartz tube at high temperature. The combustion gases are passed through an electrolyte solution in which all the chlorine (converted to hydrochloride) is absorbed and determined by microcoulometry. For the determination of organically bound chlorine content, inorganic chlorine compounds are extracted with dilute nitric acid before combustion. If the determination of organically bound chlorine is not required, extraction with nitrate acid is omitted. Any bromine present will cause interference and lead to a positive error.
In short, ISO 11480 is an international standard focusing on analytical methods in the paper and pulp industry. This standard applies to all types of pulp, paper, and cardboard, with a lower detection limit of approximately 20 mg/kg for chlorine content.
Chlorine compounds are commonly used in the bleaching of cellulose in paper production, but residual chlorine (especially organically bound chlorine) can have environmental impacts. Organically bound chlorine is often associated with adsorbable organic halogens, which are persistent pollutants that can affect water quality when released in factory wastewater.
Measuring total chlorine (inorganic + organic) and organically bound chlorine helps producers in the following areas:
The ISO 11480 standard promotes consistency between laboratories and countries by providing standardized test methods and supports global trade and environmental standards in the pulp and paper industry.
The ISO 11480 standard specifies two alternative methods for determining chlorine levels:
These methods typically involve sample preparation (e.g., combustion or extraction) followed by analytical techniques such as coulometric titration or combustion ion chromatography to measure the released chloride ions. This standard emphasizes safety, reproducibility, and the handling of interferences (e.g., those caused by bromine). It is designed for laboratory use and includes guidance on sample preparation and quantitative analysis.
Equipment manufacturers and analytical instrument suppliers (e.g., those offering total chlorine analyzers) refer to the ISO 11480 standard for compliance testing. For industries aiming for sustainable production, compliance with this standard supports certifications and regulatory reporting related to halogen content.
The importance of the ISO 11480 standard stems from environmental, regulatory, quality, and health perspectives in the pulp and paper industry. This standard is considered important for the following reasons:
Organically bound chlorine serves as a key indicator of the potential for adsorbable organic halogen formation. Accurate measurement using the ISO 11480 standard helps plants monitor and minimize these compounds, supporting the transition to elemental chlorine-free or completely chlorine-free processes that significantly reduce adsorbable organic halogen discharges.
Without standardized tests, the assessment and mitigation of wastewater toxicity would be inconsistent and would hinder global efforts to reduce pollution from an industry responsible for significant organochlorine emissions.
This encourages innovation towards sustainable production, especially as demand for eco-friendly paper (for example, in food packaging or hygiene products) increases.
In conclusion, the ISO 11480 standard plays a vital role in ensuring accurate measurement of chlorine residues in paper products, contributing to both product quality and environmental protection in a significant global industry.
For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services compliant with the ISO 11480 standard.
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