Synthesis of chitosan-based polymeric surfactants and their adsorption properties for heavy metals and fatty acids.
Chitosan-based polymeric surfactants (CBPSs) were prepared by N-acylation of chitosans (chitosan 10 and 500) with several acid anhydrides such as hexanoic (C6), lauric (C12), and palmitic (C16) anhydrides. Among the CBPS samples, CBPSs having a good solubility at pH 4.0 were selected and observed for viscosity, surface tension, and adsorption of heavy metals (Cd2+, Co2+, Cr2O7(2-), and Pb2+) as well as the fatty acid (n-octanoic acid). The 1H NMR spectrum of chitosan 10 modified with C16 at the substitution ratio of 0.4 (CBPS10-C16,0.4) showed 85% of acylation in 1% DCl/D2O solutions. CBPS10 with the substitution ratio less than 0.4 showed a good solubility because of shorter repeating units and lesser amounts of hydrophobic substituents. The intrinsic viscosity of CBPS10 was slightly increased, while that of CBPS500 was decreased. As the substitution ratio and length of the carbon chain increased, the surface tension of CBPS10 tended to decrease. CBPS10-C16,0.2 had high adsorption ability for cationic metal ions such as Cd2+, Co2+, and Pb2+ comparable to chitosan. Interestingly, CBPS(10)-C(16,0.2) showed a unique pH optimum for the anionic metal ion such as Cr2O7(2-). In addition, CBPS10-C16,0.2 exhibited the highest adsorption ability for n-octanoic acid among the tested CBPS10 with different carbon chains.
Lee
Moo-Yeal
MY
Department of International Development Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan. leem2@rpi.edu
Hong
Kyung-Jin
KJ
Kajiuchi
Toshio
T
Yang
Ji-Won
JW
D000327:Adsorption; D000812:Anhydrides / Q000737:chemistry; D002104:Cadmium / Q000737:chemistry; D002208:Caproates / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D002412:Cations; D048271:Chitosan / Q000737:chemistry*; D005227:Fatty Acids / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007850:Lauric Acids / Q000737:chemistry; D046911:Macromolecular Substances / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D019216:Metals, Heavy / Q000737:chemistry*; D008956:Models, Chemical; D019308:Palmitic Acid / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D012995:Solubility; D013055:Spectrophotometry, Infrared; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014961:X-Ray Diffraction
D000812:Anhydrides; D002208:Caproates; D002412:Cations; D005227:Fatty Acids; D007477:Ions; D007850:Lauric Acids; D046911:Macromolecular Substances; D019216:Metals, Heavy; D011108:Polymers; D002104:Cadmium; C030358:lauric acid; C037652:hexanoic acid; D019308:Palmitic Acid; D002244:Carbon; D048271:Chitosan