Phosphorus removal performance and speciation in virgin and modified argon oxygen decarburisation slag designed for wastewater treatment
2015 (English)In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 87, 271-281 p.Article in journal (Refereed) PublishedText
Argon oxygen decarburisation (ADD) slag may be used for phosphorus (P) removal, as its high pH and weatherable calcium (Ca) minerals provide sufficient Ca2+ and OH- for calcium phosphate (Ca-PO4) precipitation. This study examined the P removal performance of AOD slag for use as wastewater treatment material. Batch experiments were carried out using both synthetic P solution and real wastewater, followed by chemical modelling and X-ray absorption near edge structure (XANES) spectroscopy. The influences of initial P concentration, slag dose and modification by polyethylene glycol (PEG), an effective agent for generation of porous materials, were investigated to determine the optimal conditions for P removal by AOD slag. It was found that virgin AOD slag removed 94.8% of P from a synthetic P solution in 4 h and 97.8% in 10 h. This high P removal was accompanied by a rapid increase in pH from 7.0 to 10.74. The maximum P removal capacity (PRC) from synthetic P solution ranged from 1.3 to 27.5 mg P g(-1). The optimal AOD dose for P removal from wastewater, determined in 8-h batch experiments, was 25 g L-1. PEG modification increased the reaction rate and resulted in higher final pH, increasing PRC by 47.9%. Combined Visual MINTEQ and XANES analysis for detailed examination of P removal mechanisms revealed that the main P removal mechanism was precipitation of calcium phosphate. According to the XANES analysis, the main Ca-PO4 precipitate formed on virgin AOD slag under low initial P concentration and high pH was apatite, while brushite was the dominant product at high initial P concentration and low pH.
Place, publisher, year, edition, pages
Elsevier, 2015. Vol. 87, 271-281 p.
Phosphorus, Slag, Apatite, Brushite, Visual MINTEQ, XANES
Research subject Land and Water Resources Engineering
IdentifiersURN: urn:nbn:se:kth:diva-180991DOI: 10.1016/j.watres.2015.09.035ISI: 000367413000028ScopusID: 2-s2.0-84943241467OAI: oai:DiVA.org:kth-180991DiVA: diva2:898289
QC 201601272016-01-272016-01-262016-02-08Bibliographically approved