Chemical Cocktail Necessary for Paper Production – Some printed materials have such a distinct smell that the idea of storing them in living areas doesn’t even come to mind. However, since humans are naturally collectors and hunters, paper stacks inevitably accumulate somewhere in the house. But who really knows what chemicals are still contained in these paper stacks and how long these substances can contaminate the indoor air? It is known that the amount and type of chemicals released can vary significantly, depending on the type of paper, the manufacturing processes used, and the conditions under which the paper is stored. High temperatures and high indoor humidity accelerate the release of chemicals from paper products during storage.
Paper Manufacturers Opt for Recycling
According to the German Federal Environment Agency (UBA), the share of waste paper in paper production in Germany in 2022 was just under 80 percent. This means that the majority of the material needed for paper production comes from recycling processes and not directly from fresh wood. However, recycling waste paper requires even more chemicals than producing new paper. Waste paper recycling is a multi-stage process that includes collecting, sorting, cleaning, and processing used paper to manufacture new paper products. Chemicals play a vital role in removing printing inks, adhesives, and other contaminants that were applied to the paper during the original production and use.
Chemicals for Removing Unwanted Substances from Waste Paper
A critical step in paper recycling is de-inking, a process where printing inks and other contaminants are removed. Detergents and surfactants reduce the surface tension of water and facilitate the detachment of ink particles from the paper fibers. Sodium hydroxide (NaOH) raises the pH level and disperses the ink. Chelating agents help bind metal ions and reduce the effect of contaminants. Hydrogen peroxide (H2O2) is used for brightening the paper and removing remaining ink residues. Specific enzymes can be used to dissolve adhesive-containing contaminants. Bleaching agents serve to further brighten the paper and remove remaining ink residues.
Chemicals for Processing Fibers
The paper fibers must be processed to improve their quality and workability. Starch is added to increase the strength of the fibers. Binders are required to reconnect the fibers and strengthen the paper structure. Fillers such as calcium carbonate or kaolin are added to enhance paper quality.
Chemicals for Wastewater Treatment
The wastewater generated during the recycling process must be treated to remove contaminants before the water is released again. Flocculants and coagulating agents like aluminum sulfate or polyacrylamides are used to aggregate and remove suspended particles. pH regulators adjust the pH level of the wastewater. The use of microorganisms is a biological treatment to break down organic contaminants.
New Paper Production from Wood Fibers
Paper production is a complex process that involves converting wood fibers or other plant-based raw materials into paper. Various chemicals are used to isolate, process, and ultimately transform the fibers into paper. During wood pulping, the wood fibers are separated and turned into a pulp. This can be done mechanically, chemically, or thermomechanically. Chemical pulping uses chemicals to break down the lignin bonds between the wood fibers. Key processes include sodium hydroxide (NaOH) and sodium sulfide (Na2S), used to dissolve the lignin and release the wood fibers. In the soda process, sodium carbonate (Na2CO3) is used as a pulping chemical. After pulping, the fibers need to be bleached to remove impurities and achieve the desired paper color. Previously, elemental chlorine was used, but today chlorine dioxide (ClO2) is used due to environmental concerns. Hydrogen peroxide is an eco-friendly bleaching agent. Finally, adhesives and fillers are applied to smooth the paper surface.
Chemicals that Can Pollute Indoor Air When Storing Paper
Many of the chemicals used in paper production are organic compounds, and some of them can be volatile and enter the indoor air. This includes potentially formaldehyde and other aldehydes, which may be present as byproducts of resins and adhesives in the paper. Formaldehyde is known to be irritating and can lead to respiratory problems at higher concentrations. Phenolic compounds can be harmful and cause skin or respiratory irritation. Some solvents used in inks or coatings can be released into the air and are known to cause respiratory and central nervous system effects. Inorganic compounds like heavy metals are less volatile but can still enter the indoor air under certain conditions. Heavy metals are used as colorants or fillers in paper production. Pentachlorophenol (PCP) and other biocides are used in paper production as preservatives to prevent the growth of microorganisms. Phthalates are a group of chemicals used as plasticizers in various materials, including paper.
The Inevitable Bookcase
In smaller apartments, it’s difficult to reserve separate rooms for a library. Those who cannot avoid storing paper products in living areas should do so only to a limited extent. Regular cross-ventilation significantly improves indoor air quality. High room temperatures combined with high humidity should be avoided, as mentioned above. If residents experience health problems, professional indoor air quality testing is recommended.