title: Removal of phenols in water using chitosan-conjugated thermo-responsive polymers.
abstract: A chitosan-conjugated thermo-responsive polymer containing 15% chitosan, PNIPAAm-15CS, was used for the removal of different phenols in water. The polymer was synthesized by a 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-mediated condensation of poly(N-isopropylacrylamide-co-acrylic acid) and chitosan in the aqueous solution (pH 6). At 30 °C, phenol, 4-methylphenol, 4-methoxyphenol, and 4-chlorophenol were converted to dark brown oxidized compounds by the tyrosinase-induced enzymatic reaction and subsequently bound to the amino moiety of PNIPAAm-15CS. In the presence of 1.0 g L(-1) PNIPAAm-15 CS and 50 k UL(-1) tyrosinase, phenols (20 mg L(-1)) decreased to undetectable levels (<0.01 mg L(-1)) within 2h. By the vigorous mixing of the solution at 40 °C, the polymer deposited and became a small coagulate that can be easily taken up from water. Accompanying the polymer deposition, the oxidized compounds were completely (>98%) removed. The proposed method was successfully applied to the removal of phenols from wastewaters.
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Fro-cho, Chikusa-ku, Nagoya 464-8603, Japan. saitoh@numse.nagoya-u.ac.jp
authors.forename: Tohru
authors.initials: T
authors.lastname: Saitoh
authors.forename: Kotaro
authors.initials: K
authors.lastname: Asano
authors.forename: Masataka
authors.initials: M
authors.lastname: Hiraide
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D010084:Oxidation-Reduction; D010636:Phenols / Q000302:isolation & purification*; D011108:Polymers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D010636:Phenols; D011108:Polymers; D014874:Water Pollutants, Chemical; D048271:Chitosan