Phosphate Fixation and P Mineralogy on Natural and Ca-Modified Zeolites During Simultaneous Nutrient Removal

Research output: Contribution to journalArticleResearchpeer-review

Abstract

The recovery and recycling of nutrients (N&P) from wastewater are one of the major topics to save primary energy and resources, to raise the efficiency of wastewater treatment plants, and to foster a future circular economy. In the present study, the removal of ammonium (NH 4 +) and phosphate (PO 4 3−) using natural and Ca-treated zeolite is investigated in detail. Special emphasis is put on the simultaneous removal of both species from model solutions followed by elaborate mineralogical analyses (XRD, EPMA, FEG-SEM) for zeolite characterization and in order to determine the type, structure, and crystal sizes of CaP-phases precipitating on the zeolites surface. The effectivity of the phosphate segregation and chemical composition and the crystalline structure of the CaP-phase precipitating on the surface of the zeolite depend on the physico chemical conditions in particular on pH, molar ratio of Ca and P (due to zeolite modification), and the presence of NH 4 +. Results of simultaneous removal experiments of N&P revealed that Ca pretreatment enhances P segregation and increases the obtainable P-loadings of Ca–zeolites. Maximum P-loadings of 25 mg g −1 Ca–zeolite in binary solutions containing both ammonium and phosphate were obtained. Simultaneous phosphate removal by surface precipitation of CaP-phases does not significantly influence ammonium ion exchange and the type of CaP-precipitates formed on the zeolite surface is assumed to be mainly brushite and apatite.

Original languageEnglish
Article number41
Number of pages13
JournalWater, air, and soil pollution
Volume233.2022
Issue number2
DOIs
Publication statusPublished - 25 Jan 2022

Bibliographical note

Publisher Copyright: © 2022, The Author(s).

Cite this