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Ca(OH) 2 Pre‐Treated Bentonite for Phosphorus Removal and Recovery From Synthetic and Real Wastewater
Author(s) -
Markou Giorgos,
Mitrogiannis Dimitris,
Inglezakis Vassilis,
Muylaert Koenraad,
Koukouzas Nikolaos,
Tsoukalas Nikolaos,
Kamitsos Efstratios,
Palles Dimitrios,
Baziotis Ioannis
Publication year - 2018
Publication title -
clean – soil, air, water
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 66
eISSN - 1863-0669
pISSN - 1863-0650
DOI - 10.1002/clen.201700378
Subject(s) - bentonite , sorption , chemistry , nuclear chemistry , struvite , effluent , sorbent , phosphorus , wastewater , adsorption , phosphate , precipitation , chromatography , chemical engineering , environmental engineering , organic chemistry , physics , meteorology , engineering
The performance of chemically pre‐treated bentonite with Ca(OH) 2 toward ortho‐phosphate phosphorus (OPP) removal efficiency in synthetic (inorganic) and real (anaerobically digested effluents) wastewater (WW) is evaluated. The Ca(OH) 2 pre‐treated bentonite displays a significant increase of OPP uptake ( q e ; mg P g −1 bentonite) of 40 and 15 times, reaching about 14 and 5.5 mg P g −1 for synthetic and real WW, respectively. The optimum pH for OPP sorption is 7, while at higher pH values, although OPP removal is high due to the precipitation in the liquid phase, the OPP removal in solid phase, that is, sorption onto bentonite surface is less compared to pH 7. Scanning electron microscopy (SEM) and X‐ray diffraction (XRD) analysis shows that OPP forms various complexes with co‐existing ions in WW, such as apatite (with Ca 2+ ) and struvite (withN H 4 +and Mg 2+ ). The most influential parameter of the pre‐treatment is the dosage of Ca(OH) 2 . Concentration of 0.5 M Ca(OH) 2 or higher is necessary for an efficient pre‐treatment. In contrast, the concentration of bentonite does not affect the pre‐treatment efficiency, and a mass of 500 g L −1 bentonite is found to be sufficient. The chemical pre‐treatment with Ca(OH) 2 renders bentonite a promising low‐cost sorbent for OPP removal and recovery from WW.