Selective recycling of critical metals from the dolomitic limestone waste through multi-step alkaline precipitation integrated with CO carbonation.

Waste valorization provides a sustainable pathway for metals resource management and environmental remediation. In this study, we presented a carbon-neutral hydrometallurgical process for selectively recycling critical metals from dolomitic limestone leachate, a waste stream of phosphate mining. By incorporating thermodynamic simulation with experimental works, we achieved high-purity recovery of magnesium, calcium, aluminum, iron, manganese, and titanium via stepwise alkaline precipitation integrated with CO carbonation.

Enhanced optical properties and photocatalytic activity of TiO nanotubes by using magnetic activated carbon: evaluating photocatalytic reduction of Cr(VI).

In recent years, photocatalytic reduction of Cr(VI) to Cr(III) by TiO nanostructures, as a potent environmental technology has attracted a lot of attention. However, several defects including the large band gap energy of TiO, fast photogenerated charge recombination and re-oxidation of Cr(III) restrict their practical application. In this work, the incorporation of TiO nanotubes (TNTs) with magnetic activated carbon (MAC) and photoreduction in the presence of a hole scavenger were studied as a preferable approach.