Figure 4: Distribution coefficient (Kd) for various adsorbents in actual REE solution. The legends include adsorbents with the experimental condition (pH, contact time (CT), V/m ratio (volume of solution/mass of adsorbent and source of the REE solution)). Sources of REEs: SRW: spiked river water, SB: spiked brine, SMD: Silicate mining deposit, NMD: Niobium mining deposit, BR: Bauxite residue Source for data: Adsorbent 1-5 (Yantasee et al., 2009), 6-11 (Hu et al., 2017), 12-13 (Elsaidi et al., 2018), 14-15 (Hu et al., 2019), 16-26 (reported pH is equilibrium pH) (Callura et al., 2018).