Obtaining, Characterizing, and Evaluation of Potassium-Struvite (KMgPO4.6H2O) in Phosphorus Removal from Water: Investigation of Low-Cost Mgo Use

In this study, the possibilities of using MgO, which is an inexpensive magnesium source, in the production of the MgKPO4.xH(2)O compound called potassium-struvite were investigated. For this purpose, the effects of parameters such as Mg:K:PO4 ratio, initial pH of the environment, and time were investigated for the use of MgO in the production of potassium-struvite, by systematic experiments made out of MgO suspensions and KH2PO4 solutions. The Mg/K/P = 1/1/1 ratio was found to be appropriate from the findings obtained in the experiments. It has also been determined that a slightly alkaline environment is required for favorable precipitation. In addition, it was concluded that the aqueous medium should not be too dense, since MgO, which has low soluble properties, reacts easily. It was determined that more than 70% of the potassium ions in the environment precipitated after a short time under these conditions. It was determined that phosphate precipitated at a higher rate than potassium in a suspension containing the same mole number of MgO from a 0.25 M KH2PO4 solution. This gave the impression that a magnesium phosphate compound other than struvite also precipitated. As a result, it can be stated that magnesium oxide, which is a cheap source of magnesium, is a suitable material to be used in the production of potassium-struvite.