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Flocculation properties and adsorption kinetics of cationic starches in kaolin suspensions
Author(s) -
Chen Yanxiao,
Liu Shaoying,
Wang Gongying
Publication year - 2007
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.26025
Subject(s) - cationic polymerization , flocculation , adsorption , starch , chemistry , chemical engineering , electrokinetic phenomena , langmuir adsorption model , kinetics , titration , suspension (topology) , colloid , polymer chemistry , nuclear chemistry , inorganic chemistry , organic chemistry , physics , mathematics , quantum mechanics , homotopy , pure mathematics , engineering
The flocculation characteristics of cationic starches with degree of substitution (DS 0.32–0.63) have been evaluated in 1.0 wt % kaolin suspension by spectrophotometry and colloid titration. Cationic starch is found to be an effective flocculant for removal of anionic suspension particles. Changes in the electrokinetics of kaolin as a function of pH were investigated in the absence of flocculant. The results show that kaolin in water exhibits a negative surface charge at pH > 2.5. The negative hydrophilic surface sites of kaolin are responsible for the adsorption of cationic starch molecules. The experimental data of the adsorption of cationic starch (DS 0.51) follow a Langmuir isotherm with maximum adsorption capacities of 16.89 mg/g. For the adsorption of cationic starch, chemical reaction seems significant in the rate‐controlling step and the pseudosecond‐order chemical reaction kinetics provides the best correlation for the experimental data. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007