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Limjuco, Lawrence A.,Nisola, Grace M.,Torrejos, Rey Eliseo C.,Han, Jeong Woo,Song, Ho Seong,Parohinog, Khino J.,Koo, Sangho,Lee, Seong-Poong,Chung, Wook-Jin American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.49
<P>Crown ether (CE)-based Li+ adsorbent micro fibers (MFs) were successfully fabricated through a combined use of CE diols, electrospinning, and aerosol cross-linking. The 14- to 16-membered CEs, with varied ring subunits and cavity dimensions, have two hydroxyl groups for covalent attachments to poly(vinyl alcohol) (PVA) as the chosen matrix. The CE diols were blended with PVA and transformed into microfibers via electrospinning, a highly effective technique in minimizing CE loss during MF fabrication. Subsequent aerosol glutaraldehyde (GA) cross-linking of the electrospun CE/PVA MFs stabilized the adsorbents in water. The aerosol technique is highly effective in cross-linking the MFs at short time (5 h) with minimal volume requirement of GA solution (2.4 mL g(-1) MF). GA cross-linking alleviated CE leakage from the fibers as the CEs were securely attached with PVA through covalent CE GA PVA linkages. Three types of CE/PVA MFs were fabricated and characterized through Fourier transform infrared-attenuated total reflection, C-13 cross-polarization magic angle spinning NMR, field emission scanning electron microscope, N-2 adsorption/desorption, and universal testing machine. The MFs exhibited pseudo-second-order rate and Langmuir-type Li+ adsorption. At their saturated states, the MFs were able to use 90-99% CEs for 1:1 Li+ complexation, suggesting favorability of their microfibrous structures for CE accessibility to Lit. The MFs were highly Li+ selective in seawater. Neopentyl-bearing CE was most effective in blocking larger monovalents Na+ and K+, whereas the dibenzo CE was best in discriminating divalents Mg2+ and Ca2+. Experimental selectivity trends concur with the reaction enthalpies from density functional theory calculations, confirming the influence of CE structures and cavity dimensions in their 'size-match' Li+ selectivity.</P>
Limjuco, L.A.,Nisola, G.M.,Lawagon, C.P.,Lee, S.P.,Seo, J.G.,Kim, H.,Chung, W.J. Elsevier 2016 Colloids and surfaces. A, Physicochemical and engi Vol.504 No.-
Metatitanic acid (H<SUB>2</SUB>TiO<SUB>3</SUB>) is a promising lithium ion sieve (LIS) that can supplant the traditional manganese oxide-based LIS. To materialize its potential use in continuous Li<SUP>+</SUP> recovery, the H<SUB>2</SUB>TiO<SUB>3</SUB> (HTO) was processed as pliant composite foams. Pre-synthesized HTO particles were incorporated in poly(vinyl alcohol) (PVA) matrix (HTO/PVA) via blending, lyophilisation, and chemical cross-linking. This approach ensured the high quality and convenient loading control of HTO in the foam. The composites were thoroughly characterized and evaluated in terms of Li<SUP>+</SUP> adsorption performance and mechanical durability. At 200wt% HTO loading, the HTO/PVA had minimal capacity loss (6%) and low retardation (8%) in Li<SUP>+</SUP> uptake rate relative to the well-dispersed unsupported HTO powder. Such superior performance can be attributed to the high open pore network, uniform HTO distribution, and good wettability of the foam. Moreover, the composite maintained the Li<SUP>+</SUP> selectivity of HTO in seawater suggesting minimal non-selective metal ion adsorption on the support matrix. The foam maintained its performance and mechanical integrity after several uses, demonstrating its high suitability for long-term application in Li<SUP>+</SUP> mining from liquid resources like seawater.
( Lawrence A. Limjuco ),( Grace M. Nisola ),( Wook-jin Chung ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 ISSE 초록집 Vol.2019 No.-
Macroporous polyvinyl alcohol (PVA) foam composites with high loading of uniformly distributed lithium ion sieves (LIS) were successfully fabricated and evaluated for Li+ recovery. Surfactant blending combined with cryo-desiccation effectively produced LIS/PVA foams with hierarchical porosity composed of macro- and mesopores. Glutaraldehyde cross-linking rendered the LIS/PVA foams insoluble in water but exhibited high water absorbency and flexibility. Relative to the LIS powder, the foams exhibited minimal reductions in adsorption capacity (q<sub>e</sub>) and kinetic properties due to: (1) high total porosity and surface area, (2) hydrophilicity of PVA matrix, and (3) high LIS loading, which promoted particle exposure on the foam surface. Two types of LIS/PVA composite foams which are Mn-based (H<sub>1.6</sub>Mn<sub>1.6</sub>O<sub>4</sub>) and Ti-based (H<sub>2</sub>TiO<sub>3</sub>) LISs were fabricated; both demonstrated the effectiveness of the designed method. LIS/PVA foams with high loadings (200-300 wt%) exhibited meager reductions in q<sub>e</sub> (7-13%) and kinetic properties compared to the LIS powder. With LIS loading increase, Li<sup>+</sup> selectivity of LIS/PVA foams against other cations (i.e. Na<sup>+</sup>, K<sup>+</sup>, Mg<sup>2+</sup>, Ca<sup>2+</sup>) likewise approached that of the LIS powder. While 300 wt% HMO/PVA had low mechanical property, lower LIS loadings of 200- and 250 wt% (for both HMO and HTO) are highly durable and exhibited no deterioration in adsorption performance and reusability. This research was supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (No. 2018R1D1A1B07047503 and No. 2017R1A2B2002109) and by the Ministry of Education (No. 2009-0093816).
Zeweldi, Hana G.,Limjuco, Lawrence A.,Bendoy, Anelyn P.,Kim, Han-Seung,Park, Myoung Jun,Shon, Ho Kyong,Johnson, Eldin M.,Lee, Hanki,Chung, Wook-Jin,Nisola, Grace M. Elsevier 2018 Desalination Vol.444 No.-
<P><B>Abstract</B></P> <P>The widespread implementation of forward osmosis (FO) is highly constrained by the limited availability of suitable draw solutes (DS). Herein, monocationic hydrophilic ionic liquids (ILs) were probed as FO DS. Water (<I>J</I> <SUB> <I>v</I> </SUB>), reverse solute (<I>J</I> <SUB> <I>s</I> </SUB>), and specific reverse solute (<I>J</I> <SUB> <I>s</I> </SUB>/<I>J</I> <SUB> <I>v</I> </SUB>) fluxes were determined and correlated with IL properties: Van't Hoff factor (<I>i</I>), ionic strength, hydrated ionic radius (<I>r</I> <SUB> <I>H</I> </SUB>), diffusivity and membrane affinity. Most of the ILs have comparable <I>J</I> <SUB> <I>v</I> </SUB> with the benchmark draw solute NaCl but their <I>J</I> <SUB> <I>s</I> </SUB> were significantly lower, particularly under PRO mode. Their remarkably lower <I>J</I> <SUB> <I>s</I> </SUB>/<I>J</I> <SUB> <I>v</I> </SUB> (i.e. <0.010 ± 7.45 × 10<SUP>−4</SUP> mol L<SUP>−1</SUP>) than NaCl (0.021 ± 0.003 mol L<SUP>−1</SUP>) validates their potential use as FO DS. Tetraethylammonium bromide ([N2222]Br) is the most suitable IL DS due to its high <I>π</I>, high ionic strength, small <I>r</I> <SUB> <I>H</I> </SUB>, least membrane permeability (<I>B</I> = 0.14 L m<SUP>−2</SUP> h<SUP>−1</SUP>) and lowest <I>J</I> <SUB> <I>s</I> </SUB>/<I>J</I> <SUB> <I>v</I> </SUB> = 0.004 ± 5.53 × 10<SUP>−4</SUP> mol L<SUP>−1</SUP>. Moreover, [N2222]Br effectively desalinated seawater (0.6 M NaCl). It is thermally stable and can be effectively regenerated through direct contact membrane distillation. The final permeated water had only trace [N2222]Br, which is safe for consumption as confirmed by <I>in vitro</I> toxicity tests. These results demonstrate that certain ILs like [N2222]Br can be identified as suitable draw solutes for FO desalination process.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ionic liquids (ILs) were effectively employed as draw solutes for forward osmosis (FO). </LI> <LI> IL dissociation in water, conductivity and molecular size was important for <I>J</I> <SUB> <I>v</I> </SUB>. </LI> <LI> Hydrated radii and membrane sorption properties of ILs were critical to <I>J</I> <SUB> <I>s</I> </SUB>. </LI> <LI> All ILs especially [N2222]Br performed better than NaCl in terms of <I>J</I> <SUB> <I>s</I> </SUB>/<I>J</I> <SUB> <I>v</I> </SUB>. </LI> <LI> [N2222]Br is regenerable, has low toxicity, and has high potential as FO draw solute. </LI> </UL> </P>
Nguyen Van Tuyen,Lawrence A. Limjuco,이기세,Nhat Minh Dang 한국공업화학회 2022 공업화학 Vol.33 No.3
Microalgae is becoming a vital component for a circular economy and ultimately for sustainable development. Herein, recent developments in different outcomes of microalgae for wastewater treatment and biorefinery were reviewed. From its primary function as a third-generation resource of biofuel, the usage of microalgae has been diversified as an integral element for the CO2 sequestration and production of economically valuable products (e.g., pharmaceuticals, animal feeds, biofertilizer, biochar, etc.). Principles and recent challenges for each microalgae application were presented to suggest a motivation for future research and the direction of development. The integration of microalgae within the concept of the circular economy was also discussed with various routes of microalgae-based biorefinery.
Thakur, A.K.,Nisola, G.M.,Limjuco, L.A.,Parohinog, K.J.,Torrejos, R.E.C.,Shahi, V.K.,Chung, W.J. Korean Society of Industrial and Engineering Chemi 2017 Journal of industrial and engineering chemistry Vol.49 No.-
<P>Nano-spherical amine-rich polyethylenimine (PEI) grafted on mesoporous silica (MCM-41) (PEI/MCM-41) was developed for Cd(II) and Ni(II) removal from water. Characterization of PEI/MCM-41 using various techniques confirms its successful fabrication. Adsorption results reveal that pH and adsorbent dosage must be controlled for maximum removal. The adsorption rate was pseudo-second-order, and fitted well with Langmuir and Freundlich isotherms at equilibrium. The adsorption was thermodynamically spontaneous, endothermic and favourable. Adsorption capacities of 156.0 mg g(-1) Cd(II) and 139.7 mg g(-1) Ni(II) were on par with other high performing reported adsorbents. The PEI/MCM-41 was successfully reused demonstrating its potential for heavy metal decontamination application. (C) 2017 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.</P>