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Torrejos, Rey Eliseo C.,Nisola, Grace M.,Song, Ho Seong,Han, Jeong Woo,Lawagon, Chosel P.,Seo, Jeong Gil,Koo, Sangho,Kim, Hern,Chung, Wook-Jin Elsevier 2016 Hydrometallurgy Vol.164 No.-
<P><B>Abstract</B></P> <P>A green liquid-liquid extraction (LLE) system was developed for the recovery of lithium (Li<SUP>+</SUP>) 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<SUP>+</SUP>) carrier system (DB14C4-C18-COOH) with high Li<SUP>+</SUP> extraction performance and good stability in the room temperature ionic liquid diluent, CYPHOSIL 109. The Li<SUP>+</SUP> 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<SUP>+</SUP> which was also supported by density functional theory calculations. At room temperature, the developed LLE system effectively extracted dilute Li<SUP>+</SUP> from Na<SUP>+</SUP> (selectivity α<SUB>Li</SUB> <SUP>+</SUP> <SUB>/Na</SUB> <SUP>+</SUP> =1954) and K<SUP>+</SUP> (α<SUB>Li</SUB> <SUP>+</SUP> <SUB>/K</SUB> <SUP>+</SUP> =138). Kinetic and thermodynamic parameters were evaluated for optimum Li<SUP>+</SUP> extraction conditions. Sequestered Li<SUP>+</SUP> can be easily recovered from the LLE system using dilute hydrochloric acid. Results from recycling tests showed stable Li<SUP>+</SUP> 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<SUP>+</SUP> from brine or seawater.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Crown ether in RTIL CYPHOSIL 109 LLE system was developed for Li<SUP>+</SUP> recovery. </LI> <LI> Ligand lipophilic dibenzo14C4 crown ether with ionizable COOH group was synthesized. </LI> <LI> Highly selective LLE towards Li<SUP>+</SUP> in the presence of high Na<SUP>+</SUP> and K<SUP>+</SUP> concentration </LI> <LI> Ligand concentration, solution pH and temperature affected Li<SUP>+</SUP> extraction. </LI> <LI> Convenient Li<SUP>+</SUP> recovery and LLE reusability via dilute acid stripping treatment </LI> </UL> </P>
Design of lithium selective crown ethers: Synthesis, extraction and theoretical binding studies
Torrejos, Rey Eliseo C.,Nisola, Grace M.,Song, Ho Seong,Limjuco, Lawrence A.,Lawagon, Chosel P.,Parohinog, Khino J.,Koo, Sangho,Han, Jeong Woo,Chung, Wook-Jin Elsevier 2017 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.326 No.-
<P><B>Abstract</B></P> <P>Lithium-selective (Li<SUP>+</SUP>) 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<SUP>+</SUP> and other alkali metals (Na<SUP>+</SUP>, K<SUP>+</SUP>, Cs<SUP>+</SUP>) were assessed by liquid-liquid extraction in dichloromethane-water system. Among the CEs, the highest Li<SUP>+</SUP>/Na<SUP>+</SUP> selectivities were obtained from 3d (α<SUB>Li/Na</SUB> =2519) and 3e (α<SUB>Li/Na</SUB> =1768). DFT calculations reveal that 3d (1.28–1.37Å) and 3e (1.23–1.38Å) had the closest cavity sizes with Li<SUP>+</SUP> diameter (1.36Å). This result affirms that the size-match selectivity of CEs with Li<SUP>+</SUP> was due to the presence of bulky tetramethyl (3d) or bicyclopentyl (3e) subunits with the rigid benzo groups. Complexation with larger cations like Na<SUP>+</SUP>, K<SUP>+</SUP> and Cs<SUP>+</SUP> greatly distorted the 3d and 3e rings as indicated by the larger O-M<SUP>+</SUP> distances on their bulky sides than on their benzo sides. Thus, their (3d, 3e) superior selectivities were due to their Li<SUP>+</SUP> preference and unstable complexation with larger M<SUP>+</SUP>. Enthalpy exchange reaction mechanisms reveal the tendency of all CEs to form 2:1 CE-M<SUP>+</SUP> complexes with larger cations except for 3d, which mainly forms 1:1 CE-M<SUP>+</SUP> hence it is considered most suitable for Li<SUP>+</SUP>. The efficient synthesis of di-hydroxy CEs widens their application not only as extractants but also as solid-supported Li<SUP>+</SUP> adsorbents given the amenability of their OH– groups to further functionalization.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Li<SUP>+</SUP> selective crown ethers (CEs) with bulky and rigid subunits were efficiently synthesized. </LI> <LI> Suitable solvents, catalysts, and reaction conditions for CE synthesis were determined. </LI> <LI> Rigid subunits prevented preorganization effect while bulky groups acted as blocking moiety for bigger metals. </LI> <LI> Liquid-liquid extraction and DFT calculations provided insights on CE-M<SUP>+</SUP> complexes. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Transcript mining using fuzzy rough set theory in Oryza sativa grown under N-limited condition
David-Torrejos Yokimiko C.,Redillas Mark Christian Felipe R.,Maniquiz-Redillas Marla C.,Ubando Aristotle T.,Africa Aaron Don M.,Culaba Alvin,Kim Ju-Kon 한국식물생명공학회 2023 Plant biotechnology reports Vol.17 No.5
In rice cultivation, crop yield and productivity rely on the efficient supply of nitrogen. Mismanagement of nitrogen, such as insufficient and oversupply, lowers the plant vigor and stability. Using next-generation sequencing, transcriptome mining can discover nitrogen-responsive genes, regulators, and markers that can be used to improve the nitrogen use efficiency in rice plants. Here, we present an extension of the RNA Sequencing pipeline to generate a list of candidate genes that have the potential for molecular-based sensor development in Oryza sativa for nitrogen monitoring. The RNA Sequencing data used in this study represents 4714 genes from O. sativa seedlings that showed a dynamic response toward nitrogen availability. To generate a pool of candidate genes, we designed an algorithm for a two-step screening process that evaluates the expression of each gene across different sampling points using fuzzy logic. On the first screening, the genes were clustered based on their expression pattern, wherein a total of 135 genes from leaf tissues were found to exhibit an antagonistic response to nitrogen starvation and adaptation. These were further evaluated for the second screening where 27 genes showed at least 72% change in expression. Most of the genes were found associated with the plant’s response to stress, biotic and abiotic stimulus, transport, protein modification, and metabolic processes. This set of genes will serve as the target transcripts for nitrogen sensor development.
Rey Eliseo C. Torrejos,Grace M. Nisola,Sang Hoon Min,Jeong Woo Han,Seong-Poong Lee,Wook-Jin Chung 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.89 No.-
Novel macrocyclic extractants were synthesized and employed in liquid–liquid extraction (LLE) forpalladium/platinum (Pd/Pt) separation in aqueous feed source. Dioxadithia-benzo-crown ether diols(BCES2O2) 2g–2i were prepared through bis-epoxide cyclization with aqueous 1,2-benzenedithiol undermild basic conditions. For improved miscibility and stability in the organic diluent (i.e. toluene), 2g–2iwere alkylated to afford dimethoxy-BCES2O2 3g–3i. LLE experiments reveal their high stability,extraction efficiency, and separation performance (bPd2þ=Pt2þ ¼104105) in highly acidic feed solutions( 6 M HCl). The most suitable extractant 3i followed a 1:1 3i-Pd2+ complex with stability constantKex105. Density functional theory calculations reveal that the rigid cavity size (1.58–1.65 Å) of 3i is idealfor Pd2+ (1.56 Å) in forming S4 coordination geometry. The Pd2+ can be repeatedly extracted by 3i [intoluene] and stripped by 1 M HCl + 0.15 M thiourea solution without performance deterioration. Eachcycle can be accomplished <1 h based on the derived extraction (kex = 0.038 min 1) and stripping(kstrip = 0.063 min 1) rate constants. The high extraction efficiency (99.5%) and purity (98.5%) of recoveredPd2+ from simulated acidic spent automobile catalyst liquor demonstrate the potential of 3i [in toluene]LLE system for selective Pd2+ recovery from automotive wastes.
( Rey Eliseo C. Torrejos ),( Grace M. Nisola ),( Sang Hoon Min ),( Jeong Woo Han ),( Khino J. Parohinog ),( Seongpoong Lee ),( Wook-jin Chung ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 ISSE 초록집 Vol.2019 No.-
Dihydroxy-dithia-, -trithia-, and -tetrathia-14-crown-4 ether derivatives (2g-2m) were effectively synthesized by bis-epoxide ring-opening cyclization reaction with 1,2-benzenedithiol using a mild base triethylamine and LiCl as template in water. Experimental liquid-liquid extraction (LLE) and density functional theory (DFT) calculations reveal that the cavity size and denticity of the synthesized thiacrown ethers (CEs) affected their selectivity towards palladium (Pd) and platinum (Pt). Among the CE derivatives, bidentate dihydroxy-dibenzo-dioxadithia-14-crown ether (2i) with a calculated cavity size of 1.58-1.65 Ǻ was most selective towards Pd (1.56 Ǻ) whereas tetradentate dihydroxy-benzo-dimethyl-tetrathia-14-crown-4 ether (2m) with a cavity size of 1.31-1.60 Ǻ towards Pt (1.48 Ǻ), due to the CE cavity size-match relationship. The metals, M<sup>n+</sup> (Pd or Pt) are situated perfectly inside the CE cavity with an S4 CE-M<sup>n+</sup>complex coordination geometry and the lowest DFT calculated binding energies (ΔE<sub>CE-M</sub> <sup>n+</sup>).The dihydroxy thiacrown ethers can be further modified by alkylation for LLE application or polymerized via epoxy functionalization for solid-liquid extraction application of Pd or Pt from highly acidic auto-catalyst leachate. LLE performance of 2i in toluene-water system showed 99.99% Pd extraction efficiency with selectivity up to 10<sup>5</sup> in comparison to other competing metals from highly acidic auto-catalyst leachate. Epoxy-polymerization of epoxide functionalized CEs with diamine as curing agent to afford highly selective adsorbents for Pd or Pt separation were also investigated and showed excellent Pd and Pt separation performance. This work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (No. 2017R1D1A1B03028102).
Chung, W.J.,Torrejos, R.E.C.,Park, M.J.,Vivas, E.L.,Limjuco, L.A.,Lawagon, C.P.,Parohinog, K.J.,Lee, S.P.,Shon, H.K.,Kim, H.,Nisola, G.M. Elsevier 2017 Chemical Engineering Journal Vol.309 No.-
Electrospun composite nanofiber (NF) was fabricated and employed as an adsorbent membrane filter in a continuous Li<SUP>+</SUP> mining process from seawater. The filter was composed of a hydrophilic polyacrylonitrile (PAN) matrix infused with lithium ion sieves (LIS) H<SUB>1.6</SUB>Mn<SUB>1.6</SUB>O<SUB>4</SUB>. Characterization of the LIS/PAN NF confirmed its favorable structural and surface properties for effective Li<SUP>+</SUP> adsorption. The LIS/PAN NF was mechanically suitable as a microfiltration membrane with high water flux and low pressure requirement. Breakthrough experiments at varied feed concentrations (C<SUB>f</SUB>), seawater flowrates (F), and NF thicknesses (Z) revealed the dynamic adsorption behavior of the filter. The seawater residence time was most critical and must be kept ≥0.12min at any given C<SUB>f</SUB> and Z to maximize the Li<SUP>+</SUP> capacity of the filter. This can be conveniently achieved by adjusting the F of the process. Analogous to a packed bed system, the predictive power of nine breakthrough models were determined through non-linear regression analyses. Results reveal that bed-depth-space-time, Bohart-Adams (BA) and Thomas models adequately predicted the performance of the filter albeit BA exhibited the best agreement. Meanwhile, Wolborska failed to converge with any of the experimental results while Yoon-Nelson, Wang, Clark, dose-response, and modified dose-response were too simple to provide any meaningful information. Cycled Li<SUP>+</SUP> adsorption-desorption runs successfully collected and concentrated Li<SUP>+</SUP> in a mild acid stripping solution. After ten cycles, Li<SUP>+</SUP> was separated 155-1552 times more efficiently than Na<SUP>+</SUP>, K<SUP>+</SUP>, Mg<SUP>2+</SUP> and Ca<SUP>2+</SUP>. Overall results demonstrate the potential of LIS/PAN NF as an adsorbent membrane filter for continuous Li<SUP>+</SUP> mining from aqueous resources.