Sustainable paper manufacture from Cladophora via hydrochloric acid process.

As global demand for wood resources is projected to exceed five billion m3 by 2050, developing sustainable non-forest alternatives for paper production is an urgent industrial priority. We demonstrate a single-stage conversion of raw Cladophora biomass into papermaking fibres using aqueous hydrochloric acid at ambient conditions. The acid treatment yields cellulose-rich fibres that can be formed into sheets by standard papermaking methods, and it generates a spent liquor from which hydrochloric acid can be recovered by distillation. The recovered algal fibres form dense networks with mechanical properties comparable to commercial high-yield wood pulps. The environmental impacts of processing algal paper sheets at lab-scale were quantified using Life Cycle Assessment. Our study establishes a direct and operationally simple route for producing functional fibre networks from Cladophora, and it clarifies the sustainability limits and opportunities associated with papermaking from algae.