Facile synthesis of Ca-(OH)2-Mg nanocomposite and its applications for the removal of manganese from drinking water: A pilot study

A pilot trial was performed in a potable water treatment plant with a capacity of 16 ML/day.  The aim was to determine the removal of manganese using a mechanochemically synthesized Mg-(OH)2-Ca nanocomposite. The acquired results were underpinned by state-of-the-art analytical instruments. Specifically, the trials were performed for 157 hr using hydrated lime, periclase, and their nanocomposite individually. The key performance indicators were manganese, turbidity, electrical conductivity (EC), and pH. The results showed an increase in pH from ±7.46 to ≥7.5, ≥8.2, and ≥7.8 and EC from ±0.24 to ≥0.28, ≥0.57, and ≥0.58 mS/cm for hydrated lime, periclase, and their nanocomposite, respectively. Manganese was reduced from ±400 to ≤80 µg/L, ≤89 µg/L, and ≤54 µg/L for hydrated lime, periclase, and their nanocomposite, respectively. The NTU was reduced to ≤1 for all the chemicals but registered the following sequence: ≤0.40, ≤0.85, and ≤0.89 for hydrated lime ≥ nanocomposite ≥ periclase, respectively, from 6.45 NTU. The findings of this study demonstrated the capabilities of nanomaterials in increasing the pH of the product solution and attenuating manganese and turbidity to the required levels. Lastly, the material costs denoted R 6300.00 (323.98 USD)/week for the nanocomposite, and this was cheaper when compared to individual materials. Interestingly, the nanocomposite denoted superior and cost-effective performance compared to individual materials and will be a great success for the attenuation of manganese and other contaminants, hence enhancing its ferocious versatility in water treatment.