Effect of deinking and peroxide bleaching on the physical properties of recycled newspapers

Paper recycling for producing a new paper that can be used from old spent paper has gained increased interest, and this process helps prevent the paper from accumulating in landfills, reducing pollution and greenhouse gas emissions. In this work old newspaper (ONP) supplied from Al-Ahram Press is de-inked by washing process using sodium hydroxide, surfactant then hydrogen peroxide was applied to bleach the recycled deinked ONP. Following single-stage bleaching, the fiber properties of the pulp (brightness, tensile, tear strength, and burst index) were determined. The Effect of hydrogen peroxide dose, consistency, and temperature on the pulp brightness were studied. The deinking step produces deinked pulp with low brightness 51.75% ISO and the single-stage peroxide bleaching applied to the deinked ONP pulp could produce pulp with brightness 64.05% ISO at 60 min, 80°C, H2O2 concentration 2% and consistency 20%. The obtained data showed that the brightness of the deinked ONP increases with increasing hydrogen peroxide dose, consistency, and temperature. Also, it was found that the tensile strength and burst index increase by increasing brightness while, tear strength decreased.