Mineral recovery by bioprecipitation from desalination brine using irradiated Micrococcus luteus

Abstract Concentrated desalination brine resulting at the end of seawater desalination pose an environmental hazard due to its high mineral content. Effective treatment is crucial to mitigate its impact and enhance sustainability. An irradiated Micrococcus luteus bacterium was chosen for its tolerance to high salt concentration and was tested for mineral bioprecipitation from a desalination brine. Factorial design was employed to optimize the bioprcepitation conditions. and the bioprecepitate was characterized to evaluate the process. Plackett–Burman results demonstrate that the ratio of dilution and nitrogen sources added were significant variables as shown in the Pareto chart. Further mineral recovery optimization using response surface methodology predicted a quadratic model maximizing the mineral bioprecepitation (17.59 g/L) by adding 24.92 g/L Tryptone as supplementing nitrogen source and diluting the brine with tap water at 0.57 ratios (v/v). Scanning electron microscope image showed the topographical and morphological details while Fourier transform infrared, thermal gravimetric analysis, energy dispersive X-ray mapping and X-ray diffraction represented elemental, organic and physical characteristics of the obtained bioprecepitate. The study confirms that the use of irradiated M . luteus under optimized conditions predominately yielded hydrocalcite. This approach doesn’t only recover minerals, but can also generate water for re-use via an alternative eco-friendly approach, thus supporting the principles of circular economy. It is also an eco-friendly alternative to existing energy consuming technologies. Graphical abstract