title: Kinetic and equilibrium studies of the removal of ammonium ions from aqueous solution by rice husk ash-synthesized zeolite Y and powdered and granulated forms of mordenite.
abstract: The removal of ammonium from aqueous solutions using zeolite NaY prepared from a local agricultural waste, rice husk ash waste was investigated and a naturally occurring zeolite mordenite in powdered and granulated forms was used as comparison. Zeolite NaY and mordenite were well characterized by powder X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis and the total cation exchange capacity (CEC). CEC of the zeolites were measured as 3.15, 1.46 and 1.34 meq g(-1) for zeolite Y, powdered mordenite and granular mordenite, respectively. Adsorption kinetics and equilibrium data for the removal of NH(4)(+) ions were examined by fitting the experimental data to various models. Kinetic studies showed that the adsorption followed a pseudo-second-order reaction. The equilibrium pattern fits well with the Langmuir isotherm compared to the other isotherms. The monolayer adsorption capacity for zeolite Y (42.37 mg/g) was found to be higher than that powdered mordenite (15.13 mg/g) and granular mordenite (14.56 mg/g). Thus, it can be concluded that the low cost and economical rice husk ash-synthesized zeolite NaY could be a better sorbent for ammonium removal due to its rapid adsorption rate and higher adsorption capacity compared to natural mordenite.
authors.affiliation: Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia. alias@kimia.fs.utm.my
authors.forename: Alias Mohd
authors.initials: AM
authors.lastname: Yusof
authors.forename: Lee Kian
authors.initials: LK
authors.lastname: Keat
authors.forename: Zaharah
authors.initials: Z
authors.lastname: Ibrahim
authors.forename: Zaiton Abdul
authors.initials: ZA
authors.lastname: Majid
authors.forename: Nik Ahmad
authors.initials: NA
authors.lastname: Nizam
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D012275:Oryza; D011208:Powders; D000644:Quaternary Ammonium Compounds / Q000302:isolation & purification*; D012996:Solutions; D014867:Water; D014873:Water Pollutants / Q000302:isolation & purification*; D014961:X-Ray Diffraction; D017641:Zeolites / Q000737:chemistry*
chemical_list: D000538:Aluminum Silicates; D011208:Powders; D000644:Quaternary Ammonium Compounds; D012996:Solutions; D014873:Water Pollutants; D014867:Water; C048397:mordenite; D017641:Zeolites