title: Evaluation of the flocculation and de-flocculation performance and mechanism of polymer flocculants.
abstract: Understanding the interaction mechanism between polymeric flocculants and solid particles in two oppositely charged solutions: bentonite and calcium fluoride, is of great practical and fundamental importance. In this work, inorganic flocculants based on aluminum(III) or iron(III); cationic, anionic and non-ionic organic flocculants were used. The solution pH, which highly influenced the flocculation performance of the system, has been used as a function of turbidity removal, sediment volume and velocity. Results show that the flocculation of inorganic polymers does not depend on the zeta potential but on the solution pH, contrary for cationic and anionic polymers. Non-ionic polymer was independent on both. By varying the final pH of the heterogeneous solution formed of flocs-liquid, it was found for inorganic polymers, the optimum condition of pH < 3 to separate inorganic flocculant particles from flocs. Inductively coupled plasma atomic emission spectrometer and X-ray fluorescence analysis proved the reversibility of flocculation process by indicating the concentration of flocculant representative atom (Al or Fe) in the flocs and in the emerging solutions when the flocculation was optimized and the reversibility was effective. As results, weak forces were suggested as responsible for inorganic polymers flocculation where electrostatic interaction and hydrogen bonds may enroll the mechanism of organic flocculants.
authors.affiliation: Department of Systems Innovation, Graduate School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-Ku, Tokyo 113-8656, Japan E-mail: ponoujosiane21281@yahoo.co.jp.
authors.forename: Josiane
authors.initials: J
authors.lastname: Ponou
authors.affiliation: Toshiba Research and Development Center, Organic Materials Laboratory, Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi 212-8582, Japan.
authors.forename: Tomohito
authors.initials: T
authors.lastname: Ide
authors.affiliation: Toshiba Research and Development Center, Organic Materials Laboratory, Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi 212-8582, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Suzuki
authors.affiliation: Toshiba Research and Development Center, Organic Materials Laboratory, Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi 212-8582, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Tsuji
authors.affiliation: Department of Systems Innovation, Graduate School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-Ku, Tokyo 113-8656, Japan E-mail: ponoujosiane21281@yahoo.co.jp.
authors.forename: Li Pang
authors.initials: LP
authors.lastname: Wang
authors.affiliation: Department of Systems Innovation, Graduate School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-Ku, Tokyo 113-8656, Japan E-mail: ponoujosiane21281@yahoo.co.jp.
authors.forename: Gjergj
authors.initials: G
authors.lastname: Dodbiba
authors.affiliation: Department of Systems Innovation, Graduate School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-Ku, Tokyo 113-8656, Japan E-mail: ponoujosiane21281@yahoo.co.jp.
authors.forename: Toyohisa
authors.initials: T
authors.lastname: Fujita
mesh_terms: D001546:Bentonite / Q000737:chemistry; D002124:Calcium Fluoride / Q000737:chemistry; D005427:Flocculation; D008855:Microscopy, Electron, Scanning; D009391:Nephelometry and Turbidimetry; D011108:Polymers / Q000737:chemistry*
chemical_list: D011108:Polymers; D001546:Bentonite; D002124:Calcium Fluoride