Generation and Use of Lignin- g-AMPS in Extended DLVO Theory for Evaluating the Flocculation of Colloidal Particles

Yanzhu Guo; Fangong Kong; Pedram Fatehi

doi:10.1021/acsomega.0c02598

Generation and Use of Lignin- g-AMPS in Extended DLVO Theory for Evaluating the Flocculation of Colloidal Particles

ACS Omega. 2020 Aug 11;5(33):21032-21041. doi: 10.1021/acsomega.0c02598. eCollection 2020 Aug 25.

Authors

Yanzhu Guo^{1

2}, Fangong Kong³, Pedram Fatehi^{2

3}

Affiliations

¹ Liaoning Key Lab of Pulp and Paper Engineering, Dalian Polytechnic University, Dalian, Liaoning 116034, China.
² Department of Chemical Engineering, Lakehead University, Thunder Bay, Ontario P7B5E1, Canada.
³ Key Laboratory of Pulp & Paper Science and Technology, Ministry of Education, Qilu University of Technology, Jinan, Shandong 250353, China.

Abstract

In this work, Kraft lignin (KL) was polymerized with 2-acrylamido-2-methylpropane sulfonic acid (AMPS) to generate an anionic water-soluble KL-g-AMPS polymer. The effects of reaction conditions on the charge density of polymers were evaluated to induce lignin-based polymers with the highest anionic charge density. The optimal process conditions were 2.5 mol/mol AMPS/lignin, 0.6 g/g solid/water ratio, 2.0 initiator/lignin weight ratio, 80 °C, 120 min, and pH 1.5, which yielded KL-g-AMPS with the anionic charge density of 4.28 mequiv/g and the grafting ratio of 285%. The chemical structure and compositions of the polymers were confirmed by ¹H NMR and elemental analysis. The flocculation performance of the polymer was evaluated in an aluminum oxide suspension, and its performance was compared with that of a homopolymer of AMPS produced under the same conditions. In addition, the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory was applied to study the flocculation mechanism of the polymers and alumina particles. The results revealed that electrostatic interaction was found to be the dominant force in this flocculation process.