Internet of Things for Sustainable Mining

The sustainable mining Internet of Things deals with the applications of IoT technology to the coupled needs of sustainable recovery of metals and a healthy environment for a thriving planet. In this chapter, the IoT architecture and technology is presented to support development of a digital mining platform emphasizing the exploration of rock–fluid–environment interactions to develop extraction methods with maximum economic benefit, while maintaining and preserving both water quantity and quality, soil, and, ultimately, human health. New perspectives are provided for IoT applications in developing new mineral resources, improved management of tailings, monitoring and mitigating contamination from mining. Moreover, tools to assess the environmental and social impacts of mining including the demands on dwindling freshwater resources. The cutting-edge technologies that could be leveraged to develop the state-of-the-art sustainable mining IoT paradigm are also discussed

Liquid-liquid extraction of lithium using lipophilic dibenzo-14-crown-4 ether carboxylic acid in hydrophobic room temperature ionic liquid

A green liquid-liquid extraction (LLE) system was developed for the recovery of lithium (Li+) from sodium and potassium ions, which are typically present at high concentrations in seawater. Dibenzo-14-crown-4ether (DB14C4) was functionalized with a long lipophilic alkyl C18 chain and a pendent proton ionizable carboxylic acid group to obtain a lithium (Li+) carrier system (DB14C4-C18-COOH) with high Li+ extraction performance and good stability in the room temperature ionic liquid diluent, CYPHOSIL 109. The Li+ extraction efficiency of DB14C4-C18-COOH/CYPHOSIL 109 can be enhanced by increasing the solution pH and DB14C4-C18-COOH concentration. Further examination of extraction results reveal 1:1 coordination between DB14C4-C18-COOH and Li+ which was also supported by density functional theory calculations. At room temperature, the developed LLE system effectively extracted dilute Li+ from Na+ (selectivity alpha(++)(Li)(/Na) = 1954) and K+ (alpha K-++(Li)/ = 138). Kinetic and thermodynamic parameters were evaluated for optimum Li+ extraction conditions. Sequestered Li+ can be easily recovered from the LLE system using dilute hydrochloric acid. Results from recycling tests showed stable Li+ extraction performance hence it can be used for long term application. Overall results indicate the potential application of DB14C4-C18-COOH/CYPHOSIL 109 as a treatment step to recover Li+ from brine or seawater. (C) 2016 Elsevier B.V. All rights reserved. A green liquid-liquid extraction (LLE) system was developed for the recovery of lithium (Li+) from sodium and potassium ions, which are typically present at high concentrations in seawater. Dibenzo-14-crown-4ether (DB14C4) was functionalized with a long lipophilic alkyl C18 chain and a pendent proton ionizable carboxylic acid group to obtain a lithium (Li+) carrier system (DB14C4-C18-COOH) with high Li+ extraction performance and good stability in the room temperature ionic liquid diluent, CYPHOSIL 109. The Li+ extraction efficiency of DB14C4-C18-COOH/CYPHOSIL 109 can be enhanced by increasing the solution pH and DB14C4-C18-COOH concentration. Further examination of extraction results reveal 1:1 coordination between DB14C4-C18-COOH and Li+ which was also supported by density functional theory calculations. At room temperature, the developed LLE system effectively extracted dilute Li+ from Na+ (selectivity alpha(++)(Li)(/Na) = 1954) and K+ (alpha K-++(Li)/ = 138). Kinetic and thermodynamic parameters were evaluated for optimum Li+ extraction conditions. Sequestered Li+ can be easily recovered from the LLE system using dilute hydrochloric acid. Results from recycling tests showed stable Li+ extraction performance hence it can be used for long term application. Overall results indicate the potential application of DB14C4-C18-COOH/CYPHOSIL 109 as a treatment step to recover Li+ from brine or seawater. (C) 2016 Elsevier B.V. All rights reserved.11Nsciescopu

Design of lithium selective crown ethers: Synthesis, extraction and theoretical binding studies

Lithium-selective (Li+) di-hydroxy crown ethers (CEs 3a-3h) were efficiently synthesized via intermolecular cyclization of bulky bis-epoxide with 1,2-dihydroxybenzene. Bis-epoxides were produced by etherifying allyl bromides with bulky diols to afford diene intermediates, which were subsequently epoxidized. Optimized cyclization reactions were established by changing the solvent, catalyst, and reaction temperature. Complexation abilities of CEs 3a-3h with Li+ and other alkali metals (Na+, K+, Cs+) were assessed by liquid-liquid extraction in dichloromethane-water system. Among the CEs, the highest Li+/Na+ selectivities were obtained from 3d (alpha(Li/Na) = 2519) and 3e (alpha(Li/Na) = 1768). DFT calculations reveal that 3d (1.28-1.37 angstrom) and 3e (1.23-1.38 angstrom) had the closest cavity sizes with Li+ diameter (1.36 angstrom). This result affirms that the size-match selectivity of CEs with Li+ was due to the presence of bulky tetramethyl (3d) or bicyclopentyl (3e) subunits with the rigid benzo groups. Complexation with larger cations like Na+, K+ and Cs+ greatly distorted the 3d and 3e rings as indicated by the larger O-M+ distances on their bulky sides than on their benzo sides. Thus, their (3d, 3e) superior selectivities were due to their Li+ preference and unstable complexation with larger M+. Enthalpy exchange reaction mechanisms reveal the tendency of all CEs to form 2:1 CE-M+ complexes with larger cations except for 3d, which mainly forms 1:1 CE-M+ hence it is considered most suitable for Li+. The efficient synthesis of di-hydroxy CEs widens their application not only as extractants but also as solid-supported Li+ adsorbents given the amenability of their OH- groups to further functionalization. (C) 2017 Elsevier B.V. All rights reserved.11Nsciescopu