title: Phosphate adsorption from wastewater using zirconium (IV) hydroxide: Kinetics, thermodynamics and membrane filtration adsorption hybrid system studies.
abstract: Excessive phosphate in wastewater should be removed to control eutrophication of water bodies. The potential of employing amorphous zirconium (Zr) hydroxide to remove phosphate from synthetic wastewater was studied in batch adsorption experiments and in a submerged membrane filtration adsorption hybrid (MFAH) reactor. The adsorption data satisfactorily fitted to Langmuir, pseudo-first order and pseudo-second order models. Langmuir adsorption maxima at 22 °C and pHs of 4.0, 7.1, and 10.0 were 30.40, 18.50, and 19.60 mg P/g, respectively. At pH 7.1 and temperatures of 40 °C and 60 °C, they were 43.80 and 54.60 mg P/g, respectively. The thermodynamic parameters, ΔG° and ΔS° were negative and ΔH° was positive. FTIR, zeta potential and competitive phosphate, sulphate and nitrate adsorption data showed that the mechanism of phosphate adsorption was inner-sphere complexation. In the submerged MFAH reactor experiment, when Zr hydroxide was added at doses of 1-5 g/L once only at the start of the experiment, the removal of phosphate from 3 L of wastewater containing 10 mg P/L declined after 5 h of operation. However, when Zr hydroxide was repeatedly added at 5 g/L dose every 24 h, satisfactory removal of phosphate was maintained for 3 days.
authors.affiliation: Faculty of Engineering and Information Technology, University of Technology, Sydney, Broadway, NSW 2007, Australia.
authors.forename: M A H
authors.initials: MA
authors.lastname: Johir
authors.affiliation: Faculty of Engineering and Information Technology, University of Technology, Sydney, Broadway, NSW 2007, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Pradhan
authors.affiliation: Faculty of Engineering and Information Technology, University of Technology, Sydney, Broadway, NSW 2007, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Loganathan
authors.affiliation: Faculty of Engineering and Information Technology, University of Technology, Sydney, Broadway, NSW 2007, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Kandasamy
authors.affiliation: Faculty of Engineering and Information Technology, University of Technology, Sydney, Broadway, NSW 2007, Australia. Electronic address: s.vigneswaran@uts.edu.au.
authors.forename: S
authors.initials: S
authors.lastname: Vigneswaran
mesh_terms: D000327:Adsorption; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides / Q000737:chemistry*; D007700:Kinetics; D009566:Nitrates / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry* / Q000302:isolation & purification; D017550:Spectroscopy, Fourier Transform Infrared; D013431:Sulfates / Q000737:chemistry; D013696:Temperature; D013816:Thermodynamics; D014865:Waste Disposal, Fluid / Q000295:instrumentation* / Q000379:methods; D062065:Wastewater / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D006878:Hydroxides; D009566:Nitrates; D010710:Phosphates; D013431:Sulfates; D062065:Wastewater; D015040:Zirconium; C470523:zirconium hydroxide
keywords: Adsorption kinetics; Adsorption thermodynamics; Membrane filtration; Phosphate adsorption; Zirconium hydroxide