title: Ammonium removal from high-strength aqueous solutions by Australian zeolite.
abstract: Removal of ammonium nitrogen (NH4(+)-N) particularly from sources which are highly rich in nitrogen is important for addressing environmental pollution. Zeolites, aluminosilicate minerals, are commonly used as commercial adsorbents and ion-exchange medium in number of commercial applications due to its high adsorption capacity of ammonium (NH4(+)). However, detailed investigations on NH4(+) adsorption and ion exchange capacities of Australian natural zeolites are rare, particularly under higher NH4(+) concentrations in the medium. Therefore, this study was conducted to determine NH4(+) adsorption characteristics of Australian natural zeolites at high NH4(+) concentrations with and without other chemical compounds in an aqueous solution. Results showed that initial NH4(+) concentration, temperature, reaction time, and pH of the solution had significant effects on NH4(+) adsorption capacity of zeolite. Increased retention time and temperature generally had a positive impact on adsorption. Freundlich model fitted well with adsorption process of Australian natural zeolites; however, Langmuir model had best fitted for the adsorption process of sodium (Na(+)) treated zeolites. NaCl treatment increased the NH4(+) adsorption capacity of Australian zeolites by 25% at 1000 mg-N, NH4(+) solution. The maximum adsorption capacity of both natural Australian zeolites and Na(+) treated zeolites were estimated as 9.48 and 11.83 mg-N/g, respectively, which is lower than many zeolites from other sources. Compared to the NH4(+) only medium, presence of other competitive ions and acetic acid in the medium (resembling composition in digested swine manure slurries) reduced NH4(+) removal of natural and Na(+) treated zeolites by 44% and 57%, respectively. This suggests detailed investigations are required to determine practically achievable NH4(+) -N removal potential of zeolites for applications in complex mediums such as animal manure slurries.
authors.affiliation: a Faculty of Veterinary & Agricultural Sciences, University of Melbourne , Victoria , Australia.
authors.forename: D Thushari N
authors.initials: DT
authors.lastname: Wijesinghe
authors.affiliation: b School of Engineering, University of Melbourne , Victoria , Australia.
authors.forename: Kithsiri B
authors.initials: KB
authors.lastname: Dassanayake
authors.affiliation: c Faculty of Engineering, University of Southern Denmark , Odense , Denmark.
authors.forename: Sven G
authors.initials: SG
authors.lastname: Sommer
authors.affiliation: d Department of Agricultural Engineering , Faculty of Agriculture, University of Ruhuna , Sri Lanka.
authors.forename: Guttila Y
authors.initials: GY
authors.lastname: Jayasinghe
authors.affiliation: b School of Engineering, University of Melbourne , Victoria , Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: J Scales
authors.affiliation: a Faculty of Veterinary & Agricultural Sciences, University of Melbourne , Victoria , Australia.
authors.forename: Deli
authors.initials: D
authors.lastname: Chen
mesh_terms: D000327:Adsorption; D064751:Ammonium Compounds / Q000737:chemistry*; D000818:Animals; D008372:Manure; D009517:New South Wales; D013552:Swine; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*; D017641:Zeolites / Q000737:chemistry*
chemical_list: D064751:Ammonium Compounds; D008372:Manure; D014874:Water Pollutants, Chemical; D017641:Zeolites
keywords: Ammonium adsorption; adsorption isotherm; nitrogen recovery; waste treatment; zeolite