A novel magnesium-based oxygen releasing compound for eutrophic water remediation.

Eutrophication of surface water bodies is a global problem in recent years. Dosing polluted water with oxygen releasing compounds (ORCs), especially those that can remove excessive nutrients simultaneously is regarded as one of the most economical and eco-friendly methods of treating eutrophic waters. In this study, a novel Mg-based ORC was synthesized and characterized as a magnesium hydroxide and hydrogen peroxide complex (MHHPC) with Mg to HO ratio of 2:1. Oxygen-releasing, pH-adjusting and nutrient-removal potentials of MHHPC were evaluated in nano-pure and eutrophic water. The overall performance of MHHPC in preventing the eutrophic water from turning black and odorous was compared with the performance of other ORCs namely, MgO, CaO and the combination of MgCl and HO. The results showed that MHHPC was capable of constantly releasing oxygen to aqueous phase over a period of one week. Phosphate and ammonia nitrogen in synthetic buffered water can were removed as struvite and other precipitates from the aqueous phase. In the synthetic eutrophic water, all the ORCs tested were able to reduce aqueous ammonia nitrogen below 0.5 mM, while only CaO and MHHPC successfully removed the aqueous phosphate. However, CaO and MgCl+HO significantly inhibited microbial activity.