Flocculation of low concentration kaolin suspension using architecturally modified Xanthan gum: Effect of grafting to hyperbranching

Background: Removal of suspended kaolin at low concentration (0.25 wt.%) is tedious hence not investigated at random. An architecturally decorated semi-synthetic flocculant derived from Xanthan gum or XG, has been synthesized and specifically used to unsettle the stable kaolin suspension with high efficiency.Methods: Hyperbranched Polyacrylamide or HBPAM was grafted onto XG following Strathclyde method whereby the extent of hyperbranching of PAM was controlled by the molar ratios of brancher (methylene-bis-acrylamide or MBA) to chain transfer agent (dodecane thiol or DDT). The chemical structure was established through various analytical characterization.Significant findings: It was evident that the copolymer with maximum extent of branching (70.5%, designated as H3) exhibited fastest settling time as well as lowest turbidity simultaneously, especially at pH 7 (58 secs, 70 NTU) and at the isoelectric point (pH 4, 76 secs, 30 NTU) as compared to other hyperbranched and linear grafts of XG.