Simultaneous removal of nitrogen and phosphorus by magnesium-modified calcium silicate core-shell material in water.

Author(s) Si, Q.; Zhu, Q.; Xing, Z.
Journal Ecotoxicol Environ Saf
Date Published 2018 Aug 08

In this study, a new core-shell material (CMCS) is prepared with magnesium oxide (MgO) around calcium silicate hydrate (CSH), and CSH is prepared by SiO from the red mud. The CMCS simultaneously removes ammonia nitrogen (NH) and phosphate (PO) by chemical precipitation and it can achieve recovery of nitrogen and phosphorus. The removal process of NH and PO is as follows. First, the shell of MgO is used to remove NH and a part of the PO by the assisted adsorption and struvite (MgNHPO·6HO) precipitation method. Then the CSH is used to remove the residual part of PO by chemical precipitation (Ca(PO)OH, CaHPO and Ca(PO)). Furthermore, the MgO shell of CMCS not only removes NH and PO, but also can control the calcium ions (Ca) spill from CSH and pH in the process of removing NH and PO. The removal rate of NH and PO can reach 76.63% and 87.18%, respectively, in the solution in 80 min, but in the actual wastewater the removal rate of NH and PO is 61.40% and 62.83%, respectively. Finally, CMCS was recycled five times and its removal rates of NH and PO are 21.01% and 24.99%, respectively. The aim of this article is to present CMCS, which has a good effect on removing the NH and PO simultaneously.

DOI 10.1016/j.ecoenv.2018.07.120
ISSN 1090-2414
Citation Ecotoxicol Environ Saf. 2018;163:656664.

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