Direct electro-deposition of metallic chromium from K2CrO4 in the equimolar CaCl2-KCl molten salt and its reduction mechanism

Enhanced electrodeposition and separation of metallic Cr from soluble K2CrO4 on a liquid Zn cathode

“…The interpretation of other peaks for the blue line in Fig. 3 (a) is discussed in details in our previous work [20] . Interestingly, CrO 4 2 − shows a completely different electrochemical reduction behavior on the liquid Zn cathode.…”

“…R1' is attributed to the reduction of CrO 4 2 − to CaCr 2 O 4 (2CrO 4 2 − + 6e − + Ca 2 + = CaCr 2 O 4 + 4O 2 − ) [20] . R2' is assigned to the reduction of in-situ generated CaO to metallic Ca (CaO + 2e − = Ca + O 2 − ), which then reduced the CaCr 2 O 4 to Cr (CaCr 2 O 4 + 3Ca = 2Cr + 4CaO) [20] . Therefore, CrO 4 2 − is reduced to metallic Cr by two-step reactions with the formation of lowvalence intermediate (CaCr 2 O 4 ).…”

“…Structure optimization of graphite anode is also an effective way to mitigate the carbon contamination in cathode product [7] . However, carbon content in refractory metals is still too high, especially for metals electrodeposited from oxygenrich metal oxysalts (such as K 2 CrO 4 [20] , NaVO 3 [21] and CaTiO 3 [22] ).…”

“…In our recent works, a new method, named soluble oxysalts electrolysis (SOSE), was proposed to produce metals in a short process [7,[20][21][22]27] . Metallic Ti, V and Cr were obtained by the direct electrolysis of soluble CaTiO 3 , NaVO 3 and K 2 CrO 4 , respectively.…”

Recent bioreduction of hexavalent chromium in wastewater treatment: A review

“…Recent developments in the understanding of the conventional process emphasize various methods such as thermal treatment [27], desalination [28], direct reduction [29,30], resin adsorption [31,32,214,217], electrolysis [33,34], electrocoagulation [35,36], activated carbon adsorption [212,213], composite ceramic adsorption [37,215,218], carbon nano fibers adsorption [211,216], nano materials catalyzed reduction [38,39], and catalytic reduction [40,41]. The conventional processes are complex due to the different intensive sub-processes and use of large amounts of chemicals and generation of toxic sludges.…”