Details

Autor(en) / Beteiligte

• Yang, Kun
• Yan, Liang-guo
• Yang, Yan-ming
• Yu, Shu-jun
• Shan, Ran-ran
• Yu, Hai-qin
• Zhu, Bao-cun
• Du, Bin

Titel

Adsorptive removal of phosphate by Mg–Al and Zn–Al layered double hydroxides: Kinetics, isotherms and mechanisms

Ist Teil von

• Separation and purification technology, 2014-03, Vol.124, p.36-42

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2014

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •The removal ratio of phosphate onto Zn–Al LDH was higher than Mg–Al LDH and reached 95% respectively.•Mg–Al and Zn–Al LDHs exhibited rapid adsorption rates of phosphate and could reach equilibrium at 40min.•Phosphate species are adsorbed by LDHs via electrostatic attraction, ligand exchange and ion exchange. Phosphate removal is important for the natural water or wastewater treatment, and adsorption is an efficient treatment process. In this study, Mg–Al and Zn–Al layered double hydroxides (LDHs) were synthesized by co-precipitation method at a constant pH of 9–10. The prepared LDHs were characterized by X-ray diffraction (XRD) and BET surface area determination. The XRD patterns showed the characteristic basal reflections of hydrotalcite-like LDH materials. BET surface area of Zn–Al LDH was larger than that of Mg–Al LDH. Adsorption experiments were carried out as a function of LDHs dosage, contact time and initial pH of phosphate solution. The adsorption of phosphate reached equilibrium quickly at about 40min. The experimental data showed a good compliance with the pseudo-second-order kinetic model. The Freundlich and Langmuir models both described the adsorption isotherm data well (R2>0.98). Zeta potential and fourier transform infrared spectroscopy (FTIR) analyses were used to elucidate adsorption mechanisms. The results indicated that phosphate species were adsorbed via electrostatic attraction, ligand exchange and ion exchange. The removal ratio of phosphate onto Zn–Al LDH was higher than Mg–Al LDH and reached 95% respectively, suggesting that Mg–Al and Zn–Al LDHs were excellent adsorbents for phosphorus removal from aqueous solution.