Amberlite ir 120 resin

All abiotic leaching experiments (HCl, organic acid, and spent medium) were conducted in 50 mL flat bottomed polypropylene tubes. Each tube contained 0.1 g monazite sand ground to < 75 μm (200 mesh) and 10 mL of the desired leaching solution. Tubes were incubated at room temperature (25-28°C) and stirred at 250 rpm for 48 h.
For abiotic leaching with organic acids and hydrochloric acid, acid solutions were prepared with deionized water and filter sterilized through 0.2 μm filters prior to leaching. Acetic, citric, itaconic, oxalic, and succinic acids [Sigma-Aldrich] were tested at two concentrations each: 2 mM and 20 mM, while gluconic acid [Sigma-Aldrich] was tested at 1.8 mM and 18 mM. HCl solutions were prepared to provide a range of pH from 1.8 to 3.7. Three experimental replicates were done for each acid concentration.
For abiotic spent medium leaching, spent medium was collected after six days of bioleaching and filter sterilized through 0.2 μm filters. To remove REEs, 15 mL of filtered spent medium was added to a 50 mL tube containing 0.5 g Amberlite IR120 resin [Sigma-Aldrich] and shaken horizontally for one hour. 10 mL of treated spent medium was then used for leaching. Six biological replicates were done for each organism.