title: Paraquat adsorption on NaX and Al-MCM-41.
abstract: The aim of this work is to determine paraquat adsorption capacity of zeolite NaX and Al-MCM-41. All adsorbents were synthesized by hydrothermal method using rice husk silica. For Al-MCM-41, aluminum (Al) was added to the synthesis gel of MCM-41 with Al content of 10, 15, 20 and 25 wt%. The faujasite framework type of NaX and mesoporous characteristic of Al-MCM-41 were confirmed by X-ray diffraction. Surface area of all adsorbents determined by N2 adsorption-desorption analysis was higher than 650 m2/g. Al content and geometry were determined by X-ray fluorescence and 27Al nuclear magnetic resonance, respectively. Morphology of Al-MCM-41 were studied by transmission electron microscopy; macropores and defects were observed. The paraquat adsorption experiments were conducted using a concentration range of 80-720 mg/L for NaX and 80-560 mg/L for Al-MCM-41. The paraquat adsorption isotherms from all adsorbents fit well with the Langmuir model. The adsorption capacity of NaX was 120 mg/g-adsorbent. Regarding Al-MCM-41, the 10% Al-MCM-41 exhibited the lowest capacity of 52 mg/g-adsorbent while the other samples had adsorption capacity of 66 mg/g-adsorbent.
authors.affiliation: School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand E-mail: jatuporn@sut.ac.th.
authors.forename: Wina
authors.initials: W
authors.lastname: Rongchapo
authors.affiliation: School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand E-mail: jatuporn@sut.ac.th.
authors.forename: Krittanun
authors.initials: K
authors.lastname: Deekamwong
authors.affiliation: Department of Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Sirinuch
authors.initials: S
authors.lastname: Loiha
authors.affiliation: School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand E-mail: jatuporn@sut.ac.th.
authors.forename: Sanchai
authors.initials: S
authors.lastname: Prayoonpokarach
authors.affiliation: School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand E-mail: jatuporn@sut.ac.th.
authors.forename: Jatuporn
authors.initials: J
authors.lastname: Wittayakun
mesh_terms: D000327:Adsorption; D000535:Aluminum / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D012275:Oryza; D010269:Paraquat / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D014961:X-Ray Diffraction; D017641:Zeolites / Q000737:chemistry*
chemical_list: C509968:MCM-41; C539489:faujasite; D017641:Zeolites; D012822:Silicon Dioxide; D000535:Aluminum; D010269:Paraquat