Effect of waste eggshell particles addition on the optical properties of paper

Abstract

For this study, eggshells were collected during household food processing, and their protein membrane was manually separated from each eggshell. Membrane-removed eggshell waste was subjected to washing, drying, grinding, and sieving processes. The size of the prepared eggshell powder was less than 45 μm and was used, as an alternative to industrially precipitated calcium carbonate, in the production of laboratory paper. Filter paper was used as the basis for the paper pulp, while the filler content was varied from 5 to 20%. To determine the effect of adding eggshell powder on the optical properties of the paper, papers with the same CaCO3 content were produced in parallel as a control. It was observed that adding both types of fillers, eggshell powder and calcium carbonate, to laboratory produced paper increases its reflectance. However, the impact on L*a*b* values of paper is different for these fillers. Calcium carbonate increases its lightness (L* value) more than eggshell powder, and reduce the a* and b* value unlike eggshell powder that increases them.