Phosphate sorption to quintinite in aqueous solutions: Kinetic, thermodynamic and equilibrium analyses

Jae Hyun Kim, Jeong Ann Park, Jin Kyu Kang, Song Bae Kim, Chang Gu Lee, Sang-Hyup Lee, Jae Woo Choi

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Abstract

The aim of this study was to examine the phosphate (P) removal by quintinite from aqueous solutions. Batch experiments were performed to examine the effects of reaction time, temperature, initial phosphate concentration, initial solution pH and stream water on the phosphate adsorption to quintinite. Kinetic, thermodynamic and equilibrium isotherm models were used to analyze the experimental data. Results showed that the maximum P adsorption capacity was 4.77 mgP/g under given conditions (initial P concentration = 2–20 mgP/L; adsorbent dose = 1.2 g/L; reaction time = 4 hr). Kinetic model analysis showed that the pseudo second-order model was the most suitable for describing the kinetic data. Thermodynamic analysis indicated that phosphate sorption to quintinite increased with increasing temperature from 15 to 45°C, indicating the spontaneous and endothermic nature of sorption process (ΔH0=487.08 kJ/mol; ΔS0=1,696.12 J/(K·mol); ΔG0=-1.67 to -52.56 kJ/mol). Equilibrium isotherm analysis demonstrated that both Freundlich and Redlich-Peterson models were suitable for describing the equilibrium data. In the pH experiments, the phosphate adsorption to quintinite was not varied at pH 3.0–7.1 (1.50–1.55 mgP/g) but decreased considerably at a highly alkaline solution (0.70 mgP/g at pH 11.0). Results also indicated that under given conditions (initial P concentration=2 mgP/L; adsorbent dose=0.8 g/L; reaction time=4 hr), phosphate removal in the stream water (1.88 mgP/g) was lower than that in the synthetic solution (2.07 mgP/g), possibly due to the presence of anions such as (bi)carbonate and sulfate in the stream water.

Original languageEnglish
Pages (from-to)73-78
Number of pages6
JournalEnvironmental Engineering Research
Volume20
Issue number1
DOIs
Publication statusPublished - 2015 Mar 31

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Keywords

  • Batch experiment
  • Hydrotalcite-like particle
  • Phosphate
  • Quintinite
  • Sorption

ASJC Scopus subject areas

  • Environmental Engineering

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