A overview of the various methods of deinking waste paper

Authors

1 Department of Wood & Paper Engineering, Gorgan University of Agricaltural

2 Depatment of Wood & Paper Engineering, Gorgan University of Agricaltural

Abstract

the present study aims to evaluate chemical, floating, washing and enzymatic deinking. Efficiency of washing deinking varies depends on inks particles size and fibres wad layer. Washing phase productivity relies on papers quality and nature as well as equipment, varying 75-90. Effective washing is achieved when ink particles size ranges 10-15 micron, whereas those particles by size 5-0.5 micron are removed efficiently. Washing method is effective in removing offset ink particles and letterpress with well distribution. Floating serves as a chemical-mechanical process in which having been injected into floating cell, water bubbles adhere to ink hydrophobic particles, removing system after transmitted to floating cells. In enzymatic deinking manner, enzymes attack to fibres surface through weakening link between ink particles, fibres and finally removing fine particles and fibril. Addition of enzyme increases pollutant removing and deinking efficiency. Given to obtained results, the most important factors affecting enzymatic deinking involve temperature, PH, enzyme type, input materials, paper ingredients concentration, reaction time and mechanical operation during pulping. The enzymes used in enzymatic deinking are cellulose, xylanase and pectinase.