Nanofiltration of indium and germanium ions in aqueous solutions: Influence of pH and charge on retention and membrane flux

Speciation and Fractionation of Less-Studied Technology-Critical Elements (Nb, Ta, Ga, In, Ge, Tl, Te): A Review

“…In a binary salt mixture of In 2 (SO 4 ) 3 and GeO 2 , indium and germanium can be separated from one another by varying the pH value. This is related to a change of speciation and a change of membrane charge due to a variation in the pH value in the range of pH 2-12 [46]. The geochemical fate of indium in natural water is still poorly understood.…”

Increasing sustainability on the metallurgical industry by integration of membrane nanofiltration processes: Acid recovery

“…polyamide based active-layer membranes), where the transport of acid is driven by the transport of the anionic acid form (X -) causing the passage of H + to maintain electroneutrality in the permeate side, and; ii) negatively charged membranes to promote the transport of H + , while Xis just co-transported to achieve the electroneutrality ) and suggested that their transport was mainly controlled by diffusive and convective flow. Werner et al [33] evaluated the transport of In(III) and Ge(IV) and observed low rejections of Ge(IV) when it was presented as neutral species, while In(III) was totally rejected even when it was presented as a noncharged species (In(OH) 3 ). This was explained due to the lower size of Ge(OH) 4 than In(OH) 3 .…”

“…The transport of uncharged species has proven to have a large impact on membrane performance [23,27,[29][30][31][32][33]. One case of study is the phosphoric acid [27,29,30], which at pH<2 predominates as an uncharged species (H 3 PO 4 ) over the mono-charged anion (H 2 PO 4 -).…”

“…Transport of both uncharged solutes was mainly controlled by diffusive and convective flow, and the higher rejections values for Mo in relation to Ge were related to the higher molecular size. Werner et al [33] evaluated the transport of In(III) and Ge(IV) and observed rejection values below 15% in acidic media (due to its presence as Ge(OH) 4 ). It is worthy of mention the behaviour of In(III), which was totally rejected along with the pH range even though at neutral pH it was presented as a non-charged species (In(OH) 3 ).…”

Design and Conception of a Membrane Pilot Plant for the In Situ Treatment of Bioleaching Solutions

“…The experiments are performed at pH 2 since this pH value corresponds to the characteristics of the PLS. A series of NF experiments with synthetic leaching solution have been performed as dead‐end filtration to provide an experimental basis for the final application in the underground mine , .…”