Mixed-ligand nickel(ii) and copper(ii) complexes in competitive chelation reactions with polyaminopolyacetate and polyamine ligands

Scheglova, N. V.; Popova, Tatiana

doi:10.1007/s11172-020-2961-x

Cited by 8 publications

(2 citation statements)

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“…[33][34] Scheglova and Popova (2020) studied mixed-ligand complexes of nickel(II) and copper(II) in aqueous solution and demonstrated comparable maximum absorption wavelengths for the homoleptic nickel(II)-dien complexes of 560 nm ([Ni(dien) 2 ] 2 + ) and 610 nm ([Ni(dien)] 2 + ). [35] Their reported optimum pH range of 6.2 to 7.5 for the generation of [Ni(dien)] 2 + complex ions matches our determined pH eq range of 6.4 to 7.5 in the batch experiments for nickel(II) separation on TriA (Figure 1). Consequently, the adsorption mechanism mainly relies on complexation of one nickel(II) ion by one triamine ligand to a [Ni(TriA)] 2 + complex, irrespective of the initial pH values of the analyzed solutions.…”

Section: Chemistryopensupporting

confidence: 83%

“…Previous spectrometric experiments with diethylenetriamine (dien) in aqueous solutions of nickel(II)nitrate at different molecular ratios evidenced the formation of blue violet complex ions of the compositions [Ni(dien)] 2+ (absorption maximum λ max =580 nm) and [Ni(dien) 2 ] 2+ (λ max =540 nm) [33–34] . Scheglova and Popova (2020) studied mixed‐ligand complexes of nickel(II) and copper(II) in aqueous solution and demonstrated comparable maximum absorption wavelengths for the homoleptic nickel(II)‐dien complexes of 560 nm ([Ni(dien) 2 ] 2+ ) and 610 nm ([Ni(dien)] 2+ ) [35] . Their reported optimum pH range of 6.2 to 7.5 for the generation of [Ni(dien)] 2+ complex ions matches our determined pH eq range of 6.4 to 7.5 in the batch experiments for nickel(II) separation on TriA (Figure 1).…”

Section: Resultsmentioning

confidence: 99%

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A Pitfall in Heavy Metal Separation with Amino‐modified Silica Adsorbents from Aqueous Solution: The Occurring pH Shift

2022

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Selective separation of heavy metal ions from acidic aqueous solutions is of strong interest for certain industrial processes, such as electroplating, as well as environmental protection, for example battery recycling. Amino‐functionalized adsorbents are often discussed as suitable material for this purpose. Herein, two silica‐based adsorbents functionalized with 3‐aminopropyl‐ and 3‐[2‐[2‐aminoethylamino]‐ethylamino]‐propyl‐ligands resulting in adsorbents MonoA and TriA, respectively, were investigated regarding their separation behavior with focus on nickel(II) and cobalt(II) in batch as well as continuous flow experiments in acidic aqueous solutions. For both adsorbents, pH shifts into the alkaline range were observed in the process solutions, causing precipitation of metal hydroxides mainly in the particle pores in case of adsorbent MonoA and a combination of precipitation and adsorption regarding adsorbent TriA. Contrary to prior studies, our findings evidence that amino‐functionalized adsorbents are not applicable for nickel(II) and cobalt(II) in selective adsorption processes and additionally demonstrate that, besides batch investigations, continuous flow experiments are essential for well‐founded adsorbent selections in process development.

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Section: Chemistryopensupporting

confidence: 83%

Section: Resultsmentioning

confidence: 99%