Iron based sustainable greener technologies to treat cyanobacteria and microcystin-LR in water

The presence of the toxic cyanobacteria and cyanotoxin, microcystin-LR (MC-LR) and other cyanotoxins, in drinking water sources poses a serious risk to public health. Iron based technologies using magnetic zero-valent iron nanoparticles (nZVI) and ferrate ion (Fe^VIO₄²⁻, Fe(VI)) represent greener approaches to remove cyanobacteria and degrade MC-LR in water. This paper reveals that nanoparticles of zero valent iron (nZVI) can destroy cyanobacteria in the source water and may play a preventive role in terms of the formation of cyanobacterial water blooms by removing nutrients like phosphate. Results on MC-LR showed that Fe(VI) was highly effective in removing MC-LR in water. Products studies on the oxidation of MC-LR by Fe(VI) demonstrated decomposition of the MC-LR structure. Significantly, degradation byproducts of MC-LR did not contain significant biological toxicity. Moreover, Fe(VI) was highly effective for the degradation of MC-LR in lake water samples. Mechanisms of removal and destruction of target contaminants by nZVI and Fe(VI) are discussed.