In paper manufacturing, degumming of the raw material is done using
sulphuric acid
bleaching powder
caustic soda
nitric acid
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This question was previously asked in
UPSC CDS-2 – 2016
In paper manufacturing, the raw material (typically wood or plant fibres) contains not just cellulose but also lignin, hemicellulose, waxes, and other substances. “Degumming” is a process aimed at removing or breaking down unwanted non-cellulose components to obtain clean fibres suitable for papermaking. Alkaline solutions, such as caustic soda (sodium hydroxide, NaOH), are widely used in various pulping processes (like the Kraft process) to break down lignin and extract other materials, including some gummy substances or waxes, from the cellulose fibres.
Caustic soda is a strong alkali used in the pulping process to dissolve lignin and other impurities, separating the cellulose fibres. This process effectively “degums” or cleans the fibres before they are processed into paper. Bleaching powder is used for whitening the pulp after pulping. Sulphuric acid and nitric acid are strong acids with different applications (e.g., in chemical processing or nitration) and are not typically the primary agents for degumming in standard paper pulping, although acidic processes (like the sulfite process) exist, they target lignin and hemicellulose differently than the general removal of gummy substances often associated with alkaline treatments or specific fibre degumming steps.