title: Preparation of methacrylic acid-modified rice husk improved by an experimental design and application for paraquat adsorption.
abstract: Methacrylic acid (MAA) grafted rice husk was synthesized using graft copolymerization with Fenton's reagent as the redox initiator and applied to the adsorption of paraquat. The highest grafting percentage of 44.3% was obtained using the traditional kinetic method. However, a maximum grafting percentage of 65.3% was calculated using the central composite design. Experimental results based on the recipes predicted from the statistical analysis are consistent with theoretical calculations. A representative polymethacrylic acid-g-rice husk (PMAA-g-rice husk) copolymer was hydrolyzed to a salt type and applied to the adsorption of paraquat. The adsorption equilibrium data correlate more closely with the Langmuir isotherm than with the Freundlich equation. The maximum adsorption capacity of modified rice husk is 292.5mg/g-adsorbent. This value exceeds those for Fuller's earth and activated carbon, which are the most common binding agents used for paraquat. The samples at various stages were characterized by solid-state (13)C NMR spectroscopy.
authors.affiliation: Department of Polymer Materials, Kun Shan University, No. 949 Da-Wan Rd., Yung-Kang City, Tainan Hsien, Taiwan, ROC. shihtong@mail.ksu.edu.tw
authors.forename: Shih-Tong
authors.initials: ST
authors.lastname: Hsu
authors.forename: Lung-Chuan
authors.initials: LC
authors.lastname: Chen
authors.forename: Cheng-Chieh
authors.initials: CC
authors.lastname: Lee
authors.forename: Ting-Chung
authors.initials: TC
authors.lastname: Pan
authors.forename: Bing-Xuan
authors.initials: BX
authors.lastname: You
authors.forename: Qi-Feng
authors.initials: QF
authors.lastname: Yan
mesh_terms: D000327:Adsorption; D001673:Biodegradation, Environmental; D002244:Carbon / Q000737:chemistry; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D012275:Oryza; D010084:Oxidation-Reduction; D010269:Paraquat / Q000032:analysis / Q000302:isolation & purification*; D011108:Polymers / Q000737:chemistry; D011109:Polymethacrylic Acids; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
chemical_list: D008689:Methacrylates; D011108:Polymers; D011109:Polymethacrylic Acids; D014874:Water Pollutants, Chemical; C008384:methacrylic acid; C030613:polymethacrylic acid; D002244:Carbon; D010269:Paraquat