| Title |
Hydrometallurgical Recovery of Cr(III) from Tannery Waste: Optimization and Selectivity Investigation |
| ID_Doc |
10677 |
| Authors |
Kokkinos, E; Zouboulis, A |
| Title |
Hydrometallurgical Recovery of Cr(III) from Tannery Waste: Optimization and Selectivity Investigation |
| Year |
2020 |
| Published |
Water, 12, 3 |
| DOI |
10.3390/w12030719 |
| Abstract |
Tanneries produce significant quantities of hazardous waste/waters and, according to international environmental organizations, their further recycling/reuse/exploitation in the context of circular economy is considered mandatory. A relevant case study is the recovery of Cr(III), used in large amounts during the tanning process, which can be recovered from the corresponding industrial waste/sludge. The aim of this work is to optimize the Cr(III) hydrometallurgical recovery from the tannery sludge by examining the major experimental conditions that affect the efficiency of its different sequential steps, namely extraction/leaching and precipitation. The chemical characterization revealed that tannery sludge contains high amounts of Cr(III) (14.1%), Ca (14.8%), and organic matter (22%). The extraction of Cr(III) was examined by applying various common acids (H2SO4, HNO3, HCl) in the concentration range of 0.02-2 N. The highest selectivity and efficiency (93%) were obtained by the addition of H2SO4 as the insoluble CaSO4 and soluble CrSO4+ species were formed. Regarding the experimental conditions, only the increase in temperature showed a positive effect on Cr recovery. The Cr(III) can be further precipitated from the resulting leaching solution by increasing the equilibrium pH; the precipitate with the higher purity in Cr(OH)(3) (70%) was obtained by the application of NaOH and could possibly be reused by tanneries. |
| Author Keywords |
tannery waste management; chromium(III) recovery; hydrometallurgy |
| Index Keywords |
Index Keywords |
| Document Type |
Other |
| Open Access |
Open Access |
| Source |
Science Citation Index Expanded (SCI-EXPANDED) |
| EID |
WOS:000529249500104 |
| WoS Category |
Environmental Sciences; Water Resources |
| Research Area |
Environmental Sciences & Ecology; Water Resources |
| PDF |
https://www.mdpi.com/2073-4441/12/3/719/pdf?version=1583493021
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