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Electrochemical Stripping Analysis
Published in Grinberg Nelu, Rodriguez Sonia, Ewing’s Analytical Instrumentation Handbook, Fourth Edition, 2019
Baldwin et al. [64] reported on the determination of traces of nickel based on a dimethylglyoxime-containing carbon paste electrode. A poly(vinylpyridine)-coated platinum electrode can be used for measuring low levels of Cr(VI) [65]. Trace measurements of uranium can be obtained at a trioctylphosphine oxide-coated glassy carbon electrode [66]. Nafion- [67] or amine- [68] modified electrodes can be used to preconcentrate organic analytes; in the latter case, the preconcentration is based on covalent attachment. Bioaccumulation [69] and biocatalytic processes [70] can also be exploited to obtain desired sensitivity and selectivity enhancements.
Valorization of resources from end-of-life lithium-ion batteries: A review
Published in Critical Reviews in Environmental Science and Technology, 2022
Francine Duarte Castro, Mentore Vaccari, Laura Cutaia
Metal separation by precipitation is based on the difference in solubility of the various chemical species of a mixture in the presence of strategically added reagents. The fact that solubility changes by changing the pH is used in favor of the separation. Potassium permanganate can precipitate manganese as manganese dioxide at pH 2 and temperatures between 40 and 50 °C; dimethylglyoxime (DMG) can be used to precipitate nickel in the presence of ammonia at a pH ranging from 8 to 11 (Vanitha & Balasubramanian, 2013). Fe, Al, and Cu are usually removed at the beginning of the recovery step. They are easily removed by precipitation with NaOH as hydroxides at low pHs (3–6) (Zou et al., 2013). Using NaOH, Ni, Mn and Co can be selectively precipitated as hydroxides at higher pHs (8–12). These metals can be removed in the form of carbonates, by adding Na2CO3 (Zhang, Li, et al., 2018), in the form of sulfides at a pH ranging from 6 to 10, using (NH4)2S (Wang et al., 2011), and others. Lithium can be recovered as carbonate (Li2CO3), fluoride (LiF), or phosphate (Li3PO4) (Zhang, Li, et al., 2018).
A Review on Environmental, Economic and Hydrometallurgical Processes of Recycling Spent Lithium-ion Batteries
Published in Mineral Processing and Extractive Metallurgy Review, 2021
E Asadi Dalini, Gh. Karimi, S. Zandevakili, M. Goodarzi
(Chen et al. 2016) using 1.5 M citric acid and 0.5 g/g D-glucose under conditions of S/L 20 g.L−1, 80°C and 2 h succeeded in achieving leaching efficiency of 99% Li, 91% Ni, 92% Co and 94% Mn. Manganese ions were recovered by 0.5 M potassium permanganate to the oxide form (MnO2 or Mn2O3). Subsequently, adding 0.2 M dimethylglyoxime (DMG), 0.5 M oxalic acid and 0.5 M H3PO4 under optimum conditions (20 min, 300 rpm, precipitant dosage 1 and 25°C), nickel, cobalt, and lithium ions were precipitated to forms Ni(C4 H6N2O2)2, CoC2O4.2H2O and Li3PO4, respectively. Under the mentioned conditions, recovery efficiency for Ni, Co and Liwas98.5%, 96.8% and 92.7%, respectively. The precipitation reactions for metals were as follows:
Biochar-loaded nZVI/Ni bimetallic particles for hexavalent chromium removal from aqueous solution
Published in Journal of Dispersion Science and Technology, 2023
Sijing Zeng, Dengjie Zhong, Yunlan Xu, Nianbing Zhong
The morphological characterization of BC@nZVI/Ni was observed by SEM (Apreo S HiVac FEI). The X-ray diffraction patterns in the range of 10-80° were obtained by XRD (Shimadzu XRD-6100) and used to identify the crystal structure. Functional groups of BC@nZVI/Ni were identified by FTIR (Nicolet 670). The element valence state of BC@nZVI/Ni before and after reaction were obtained by XPS (Thermo Scientific K-Alpha). Measurement of Cr(VI), iron and nickel concentration relied on diphenylcarbazide spectrophotometry,[25] phenanthroline spectrophotometry [26] and dimethylglyoxime spectrophotometric method.[27]