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Publikationstyp
Wissenschaftlicher Artikel
Erscheinungsjahr
2019
Quantification and isotherm modelling of competitive phosphate and silicate adsorption onto micro-sized granular ferric hydroxide
Quantification and isotherm modelling of competitive phosphate and silicate adsorption onto micro-sized granular ferric hydroxide
Autor:innen
Herausgeber
Quelle
RSC Advances
9 (2019), Heft 45
9 (2019), Heft 45
Schlagwörter
Zitation
HILBRANDT, Inga, Vito LEHMANN, Frederik ZIETZSCHMANN und Aki Sebastian RUHL, 2019. Quantification and isotherm modelling of competitive phosphate and silicate adsorption onto micro-sized granular ferric hydroxide. RSC Advances [online]. 2019. Bd. 9 (2019), Heft 45. DOI 10.60810/openumwelt-1147. Verfügbar unter: https://openumwelt.de/handle/123456789/5125
Zusammenfassung englisch
Adsorption onto ferric hydroxide is a known method to reach very low residual phosphate concentrations. Silicate is omnipresent in surface and industrial waters and reduces the adsorption capacity of ferric hydroxides. The present article focusses on the influences of silicate concentration and contact time on the adsorption of phosphate to a micro-sized iron hydroxide adsorbent (nGFH) and fits adsorption data to multi-component adsorption isotherms. In Berlin drinking water (DOC of approx. 4 mg L-1) at pH 7.0, loadings of 24 mg g-1 P (with 3 mg L-1 initial PO43--P) and 17 mg L-1 Si (with 9 mg L-1 initial Si) were reached. In deionized water, phosphate shows a high percentage of reversible bonds to nGFH while silicate adsorption is not reversible probably due to polymerization. Depending on the initial silicate concentration, phosphate loadings are reduced by 27, 33 and 47% (for equilibrium concentrations of 1.5 mg L-1) for 9, 14 and 22 mg L-1 Si respectively. Out of eight tested multi-component adsorption models, the Extended Freundlich Model Isotherm (EFMI) describes the simultaneous adsorption of phosphate and silicate best. Thus, providing the means to predict and control phosphate removal. Longer contact times of the adsorbent with silicate prior to addition of phosphate reduce phosphate adsorption significantly. Compared to 7 days of contact with silicate (c0 = 10 mg L-1) prior to phosphate (c0 = 3 mg L-1) addition, 28 and 56 days reduce the nGFH capacity for phosphate by 21 and 43%, respectively. Quelle: https://pubs.rsc.org