Acid mine drainage (AMD) is an iron-rich acidic wastewater that poses grave environmental risks, but also present opportunities for resource recovery. Here, Fe(III) was facilely recovered from AMD and subsequently used ferric chloride (FeCl 3 ) production for water coagulation. To this end, magnesium oxide (MgO) nanoparticles, i.e., derived from thermally activated cryptocrystalline magnesite, were used to selectively precipitate and recover Fe(III) from AMD. State-of-the-art instruments (i.e., HR-FIB-SEM-EDS) shed light on the characteristics and composition of the recovered material, confirming that Fe(II) was recovered, along with minor concentrations of Al, Ca, Mg, and sulfate. However, without the problem of high sulfate co-precipitation encountered with calcium- and sodium-based agents. This material was then reacted with hydrochloric acid (HCl) towards FeCl 3 synthesis, which was then employed for water/wastewater coagulation-flocculation-settling treatment. Optimum conditions for South African river water treatment included 0.2 mL/L (v/v ratio), 100 rpm mixing speed, and 5 min contact time. Turbidity, Fe, and Al removals exceeded 99%, meeting the South African drinking water (SANS 241) standard. Most notably, the performance of the AMD-synthesized FeCl 3 was on par with commercially available FeCl 3 , with no meaningful statistical differences being observed. However, the cost of using synthesized ferric chloride for water treatment is R9,04 (0,53 USD), whilst the cost of using commercial ferric chloride for water treatment is R21 (1,23 USD), thus, to a larger extent, making it 56,95% less than the cost of commercial ferric chloride and this present a new sustainable approach to redress challenges of dwindling raw resources. This highlights that AMD-synthesized FeCl 3 can be safely employed by the water and wastewater industry to underpin sustainability and address price and availability concerns which surrounds commercial coagulants/flocculants. Furthermore, through AMD beneficiation, i.e., Fe(III) recovery, and partial acidity correction, water reclamation opportunities from AMD can be further pursued. Overall, resource recovery from waste and their reuse for treating other wastes can introduce sustainable paradigms and promote the United Nations (UN) sustainable development goals (SDGs). • Novel recovery of Fe(III) from acid mine drainage for FeCl 3 coagulant production. • Optimum conditions were 0.2 mL/L (v/v ratio), 100 rpm of mixing speed, and 5 min. • Synthetic FeCl 3 demonstrated superior performance as compared to commercial FeCl 3 . • Synthesized FeCl 3 demonstrated tenacity in drinking water and wastewater treatment. • Circular economy, waste beneficiation and waste valorization were sheerly elucidated herein.
Mahlohla et al. (Sun,) studied this question.