Deinking of Black Toner Ink from Laser Printed Paper by using Anionic Surfactant
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Date
2017-10
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Addis Ababa University
Abstract
The purpose of this research was to synthesize one type of natural anionic surfactant (fatty acid soap) from renewable material (natural oil) and use of this surfactant for ink removal from waste 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 fatty acid soap surfactant and deinking flotation of waste printed paper. Foamability and foam stability, critical micelle concentration and hydrophilic lipophilic balance (HLB) of the surfactant were determined to evaluate its fundamental surface active properties for the purpose of deinking flotation. HLB value was determined by calculating the ration of hydrocarbon chain (composed of carbons and hydrogens and the carboxylic acid group on one end which is ionic bonded to a metal ion of the surfactant. 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. Differences in flotation efficiency could be explained based on flotation operation parameters, foaming and surface active characteristics of the surfactant. The experimental design selected for this study was the Central Composite Design (CCD).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 78.0219 % at the flotation time of 90min, fatty acid soap dosage of 1.5% and pH of 9. The minimum ink removal efficiency was also found to be 49.3715% at flotation time of 150min, fatty acid soap dosage of 3% and pH of 3. 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.
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Keywords
Anionic Surfactant, Waste Paper, Flotation Deinking, Hand Sheet, Effective Residual Ink Concentration