A biobased material derived from cellulose powder has been demonstrated to effectively remove toxic dyes from industrial wastewater.

The treatment scheme developed by researchers from Malaviya National Institute of Technology (India) and Chalmers University of Technology (Sweden) requires neither pressure nor heat and uses sunlight to catalyze the process. Wood waste from the lumber or pulp and paper industries could serve as a source for the cellulose used in the filtration media. Application of an acid treatment infuses the nanocrystals with a negative charge and enhances selective adsorption of dye molecules. The captured dye degrades into a less toxic form when exposed to sunlight.

Cellulose nanocrystal-based filters selectively absorb dye from textile factory wastewater streams. Trapped dye then breaks down by exposure to sunlight (inset). Source: David Ljungberg/Chalmers University of Technology

Research published in Industrial & Engineering Chemistry Research reports a Langmuir adsorption capacity of about 77 mg/g for the cellulose nanocrystals, which eliminated more than 80% of the dye from complex industrial wastewater samples.

The researchers plan to explore the efficacy of this nanocrystal filtration technology in removing heavy metals and other pollutants from industrial wastewater systems.