Elevated nitrate levels are a significant concern in agriculture intensive countries. High concentrations of nitrate affect drinking water supplies, aquatic life and damage ecosystems. Zero valent iron nanoparticles (nZVI) doped with a secondary metal is a potential remediation tool. However, the main issues of nanosized particles are bioaccumulation and aggregation. Supporting bimetallic nZVI on non-toxic supports is one solution to minimize the toxicity as well as aggregation.<br/>In this work, natural microsilicate from thermal waste in New Zealand was used as a support. Two different synthetic methods, including co-reduction and deposition, were utilised for synthesising supported nZVI doping with secondary metal of Ni and Cu. Morphologies and structures of these materials were investigated using SEM, TEM. Bimetallic nZVI particles are spherical with aggregation of cluster. Evolutions of structure have been clarified in conjunction with high resolution TEM- EDS mapping. This showed that secondary metal (Ni or Cu) was mostly arranged on the outer shell (surface) of nZVI in deposited bimetallic nanoparticles.<br/>In terms of nitrate removal, these materials were more reactive than bare nZVI on microsilicate, reducing nitrate more efficiently with faster rates. The interference with inorganic ions was also minimal. Additionally, phosphate was simultaneously removed during nitrate reduction. Therefore, these materials are promisingly potential applications for removing contaminants from water.

New method for nitrate remediation from water

256th National Meeting (2018)

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