Deinking of Black Toner Ink from Laser Printed Paper by Using Anionic Surfactant

The objective of this research was to synthesize natural anionic surfactant from renewable material and use of this surfactant for ink removal from printed paper via flotation deinking in paper recycling process. The work included the preparation of the castor seed raw material, extraction of castor oil, preparation of anionic surfactant and deinking flotation of waste printed paper. Foamability and foam stability, critical micelle concentration and hydrophilic lipophilic balance of the surfactant was characterized and used to evaluate its fundamental deinking ability properties for the purpose of deinking flotation. The hydrophilic-lipophilic balance (HLB) of the fatty acid soap of 19.48, average Foamability height of 49cm and critical micelle concentration (CMC) of 0.0065M was obtained. Lab scale flotation deinking process was done and the basic flotation parameters like flotation time, fatty acid soap dosage and pH were optimized for evaluating deinking efficiency. The flotation deinking efficiency was probed by measuring the residual ink concentration of the hand sheet via Perkin Elmer spectroscopy before and after deinking flotation. The individual and interaction effects between the basic parameters were studied by using design Expert Software 6.0.8. For the deinking flotation, the maximum ink removal efficiency was determined to be 78.02% at the flotation time of 90min, fatty acid soap dosage of 1.5% and pH of 9. Increasing flotation time from 30min up to 90 min and decreasing fatty acid dosage from 3% to 1.5% and increasing of pH from 3 up to 9 were found to have increased the ink removal efficiency.