Chloride Ionic Liquid Research Articles

Solvothermal syntheses and properties of europium metal organic framework with 1, 3-bis(carboxymethyl)imidazolium chloride ionic liquid

A new lanthanide metal organic framework, namely [Eu(C7H7O4N2)(H2O)2(Cl0.38)2]Cl1.24 (1), was solvothermally synthesized using 1,3-bis(carboxymethyl)imidazolium chloride ([H2imdc]Cl) ionic liquid as a ligand. This compound was structurally characterized by single crystal X-ray diffraction and its properties were analyzed spectroscopy and theoretical studies. In 1, Eu (III) ions have only one coordination environment, and the ligands exhibit one coordination mode. The Eu3+ ions and ligands are connected to construct wavelike 2D cationic layers through coordination bonds, and then the 2D networks further interconnected through hydrogen bonds. The luminescent properties were studied at 77 K. The emission spectrum shows that there is one Eu3+ ion site in asymmetric unit, which is consistent with the results of the X-ray crystal structure analysis. Compound 1 exhibits characteristic emission bands of Eu3+ with emission lifetime of 0.336 ms.

Electrodeposition of Ag-W Alloy Films from Ionic Liquid for Electrical Contacts

The global e-mobility market is experiencing strong growth. As a driving force, China increased its share of electric vehicles by nearly 400% from 0.3 million in 2015 to 1.25 million in 2018. The increase in registrations of electric vehicles in the US shows a similar percentage, from 0.14 to 0.36 million in the last five years. Within twenty years, electric vehicles may account for 45 percent of total car sales worldwide. In the automotive industry, the present motor performance along with its steady increase suggests using very powerful electric motors with, at least temporary, very high power consumption. For the required high currents, new coating concepts for build-in electric contacts are necessary. By far, silver-tungsten alloys are the most popular contact materials. Tungsten is the choice of material when currents are switched. Sintered or infiltrated tungsten-silver contacts can be used from the 1 to 800 kV range. At high voltages, arcing can briefly occur at the contacts during switching with currents up to 100 kA, which results in very high temperatures (> 10,000 K). In silver-tungsten alloys, the ability of tungsten to withstand thermal, mechanical, and electrical wear, combined with the high electrical conductivity of silver make them the appropriate materials. However, the electrodeposition of these alloys from aqueous solutions is not yet state of the art. This presentation shows a way to produce these contact materials by electrodeposition from non-aqueous ionic liquids. Silver-tungsten alloy films for application as electrical contacts were prepared using tungsten hexachloride, silver chloride and anhydrous 1-ethyl-3-methylimidazolium chloride (EMIMCl) ionic-liquid solution with aluminium chloride in different ratios. The deposition takes place outside the glove box. The crystalline structure of the alloys were investigated by X-ray diffraction (XRD). The chemical composition was characterized by scanning electron microscopy (SEM) and inductively-coupled plasma optical emission spectroscopy (ICP-OES). The shown electrodeposition of tungsten-base alloys with silver make the time-consuming and expensive sintering process redundant and lead to thin, lightweight, and low-cost contacts while saving resources.

Impact of non‐solvent on regeneration of cellulose dissolved in 1‐(carboxymethyl)pyridinium chloride ionic liquid

AbstractCellulose dissolved in ionic liquid (1‐(carboxymethyl)pyridinium chloride)/water (60/40 w/w) mixture is regenerated in various non‐solvents, namely water, ethanol, methanol and acetone, to gain more insight into the contribution of non‐solvent medium to the morphology of regenerated cellulose. To this end, the initial and regenerated celluloses were characterized with respect to crystallinity, thermal stability, chemical structure and surface morphology using wide‐angle X‐ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy and scanning electron microscopy. According to the results, regardless of non‐solvent type, all regenerated samples have the same chemical structure and lower crystallinity in comparison to the initial cellulose, making them a promising candidate for efficient biofuel production based on enzymatic hydrolysis of cellulose. The reduction in crystallinity of regenerated samples is explained based on the potential of the non‐solvent to break the hydrogen bonds between cellulose chains and ionic liquid molecules as well as the affinity of water and non‐solvent which can be evaluated based on Hansen solubility parameter. The latter also determines the phase‐separation mechanism during the regeneration process, which in turn affects surface morphology of the regenerated cellulose. The pivotal effect of regenerated cellulose crystallinity on its thermal stability is also demonstrated. Regenerated cellulose with lower crystallinity is more susceptible to molecular rearrangement during heating and hence exhibits enhanced thermal stability. © 2019 Society of Chemical Industry

2‐Methyl‐1,3‐disulfoimidazolium polyoxometalate hybrid catalytic systems as equivalent safer alternatives to concentrated sulfuric acid in nitration of aromatic compounds

Ionic liquid‐derived polyoxometalate salts [mdsim]3[PM12O40] (where M = W and Mo) of two heteropolyacids H3PW12O40.nH2O and H3PMo12O40.nH2O were synthesized using 2‐methyl‐1,3‐disulfoimidazolium chloride ([mdsim][Cl]) ionic liquid and the corresponding heteropolyacids. Three equivalents of [mdsim][Cl] were treated with the respective Keggin‐structured heteropolyacids (one equivalent) in aqueous medium at room temperature to afford the water‐stable ionic polyoxometalates as acidic solids. They were completely characterized using spectroscopic and other analytical techniques including thermal analysis and Hammett acidity studies. The inherent Brønsted acidic properties of ─SO3H group of these polyoxometalate salts were studied for the nitration of aromatic compounds with 69% HNO3 at normal temperature and 80°C without use of any external concentrated sulfuric acid. These strongly acidic polyoxometalates display good recyclability and efficient reusability.

Cationic micelles self-assembled from quaternized cellulose-g-oligo (ε-caprolactone) amphiphilic copolymers

A novel kind of cationic cellulose-g-oligo(ε-caprolactone) amphiphilic polymer (QC-g-OCL) was obtained by homogeneous ring-opening polymerization of ε-caprolactone (ε-CL) from quaternized cellulose (QC) in 1-butyl-3-methylimidazolium chloride (BmimCl) ionic liquids. Chemical structures and properties of the copolymers were characterized by FT-IR, 1H NMR, 13C NMR, XRD and TGA techniques. The grafting ratios of OCL chain onto QC-g-OCL were adjusted by changing the molar ratio of CL to QC. The micelles self-assembled from QC-g-OCL were prepared by ultrasonic-assisted dissolution method, and comprehensively analyzed by dynamic light scattering (DLS), TEM and fluorescence spectroscopy techniques. The micelles were in spherical shape with average hydrodynamic radiuses (Rh) in the range of 170–237 nm. Moreover, their critical micelle concentration (CMC) values were decreased from 0.302 mg/mL to 0.089 mg/mL with increasing the degree substitution values of OCL (DSOCL) from 0.16 to 0.60. The ζ-potentials of micelles in water were ranged from 37.2 mV to 48.3 mV, indicating that the shells of micelles were constituted by ationic quaternary ammonium group. All of these findings established that the cationic cellulose-based micelles would be a promising aqueous carrier for hydrophobic drug.

Effect of Alkyl Chain Length on Derived Thermodynamic Properties of 1-Alkyl-3-methylimidizolium Chloride Ionic Liquids and Their Mixtures with Ethanol

Densities of the ionic liquids [C2C1im]Cl, [C3C1im]Cl, [C4C1im]Cl, and [C6C1im]Cl and their mixtures with ethanol were determined up to 40 MPa and 398 K. Density was modeled as a function of temperature, pressure, and composition using the Sanchez–Lacombe equation of state. Using the model, derived thermodynamic properties, namely isothermal compressibility, isobaric expansivity, and internal pressure, were calculated. This allowed for the estimation of the Hildebrand solubility parameters of these ionic liquids (ILs). Internal pressure was found to go through a maximum at low concentrations of ionic liquid in the case of [C3C1im]Cl, [C4C1im]Cl, and [C6C1im]Cl. These observations were interpreted in terms of a significant effect of the alkyl chain length on the interactions between the IL and the cosolvent, ethanol. It is speculated that this is in part due to possible clustering between the anion (Cl–) and ethanol.

A safe and non-flammable sodium metal battery based on an ionic liquid electrolyte

Rechargeable sodium metal batteries with high energy density could be important to a wide range of energy applications in modern society. The pursuit of higher energy density should ideally come with high safety, a goal difficult for electrolytes based on organic solvents. Here we report a chloroaluminate ionic liquid electrolyte comprised of aluminium chloride/1-methyl-3-ethylimidazolium chloride/sodium chloride ionic liquid spiked with two important additives, ethylaluminum dichloride and 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide. This leads to the first chloroaluminate based ionic liquid electrolyte for rechargeable sodium metal battery. The obtained batteries reached voltages up to ~ 4 V, high Coulombic efficiency up to 99.9%, and high energy and power density of ~ 420 Wh kg−1 and ~ 1766 W kg−1, respectively. The batteries retained over 90% of the original capacity after 700 cycles, suggesting an effective approach to sodium metal batteries with high energy/high power density, long cycle life and high safety.

Structural Destabilization of Azurin by Imidazolium Chloride Ionic Liquids in Aqueous Solution.

Alkyl imidazolium chloride ionic liquids (ILs) have been used for numerous biochemical applications. Their hydrophobicity can be tuned by changing the alkyl chain length, and longer-chain ILs can form micelles in aqueous solution. We have investigated the effects of imidazolium chloride ILs on the structure and stability of azurin, which is a very stable Cu2+ redox protein with both α-helix and β-sheet domains. Temperature-dependent infrared (IR) and vibrational circular dichroism spectroscopy can provide secondary-structure-specific information about how the protein is affected, and temperature-jump transient IR measurements can quantify the IL-influenced unfolding dynamics. Using these techniques, we can quantify how azurin is destabilized by 1.0 M ILs in aqueous solution. The shorter, less hydrophobic ILs, 1-butyl-3-methylimidazolium chloride and 1-hexyl-3-methylimidazolium chloride likely interact with the α-helix domain and decrease protein melting temperature from 82 °C without IL to 55 °C and disturb the overall tertiary structure, resulting in a looser, more open shape. Thermodynamic analysis indicates that protein destabilization is due to increased unfolding entropy. 1-Octyl-3-methylimidazolium chloride [OMIM]Cl, which forms micelles in solution that may partially solvate the protein, has a more significant destabilizing effect, resulting in a melting temperature of 35 °C, larger unfolding entropy, and relaxation kinetics several orders of magnitude faster than with unperturbed azurin. The temperature-independence of the relaxation time constant suggests that in the presence of [OMIM]Cl, the protein folding potential energy surface has become very smooth.

Ionic liquids skeleton typed magnetic core-shell molecularly imprinted polymers for the specific recognition of lysozyme

The novel ionic liquids skeleton typed magnetic core-shell molecularly imprinted polymers (Fe3O4–COOH@IL-MIP) were firstly constructed with 1-vinyl-3-aminoformylmethyl imidazolium chloride ionic liquid ([VAFMIM]Cl-IL) modified magnetic particles as the substrate materials, [VAFMIM]Cl-IL as functional monomer, 1,6-hexanediyl-3,3′-bis-1-vinylimidazolium dichloride ionic liquid as cross-linker and Lysozyme (Lys) as template protein via surface-imprinting technique. The structure of Fe3O4–COOH@IL-MIP were confirmed by transmission and scanning electron microscopy, dynamic light scattering, thermo-gravimetric analysis, fourier transform infrared spectrometry and X-ray diffraction. The adsorption mechanism was discussed from the perspective of amino acid residues of Lys. The maximum adsorption capacity of MIPs was 166.36 mg g−1 and imprinting factor was 2.67. The competitive adsorption experiments demonstrated the favorable recognition ability of MIPs toward Lys. Reusability studies indicated MIPs can be reused ten times without obvious loss of rebinding ability. The Lys conformation maintained intact after elution and the elution rate was as high as 74%. The adsorption experiment of egg white manifested that MIPs can effectively separate Lys in practical samples. Only ILs and Fe3O4 were utilized to fabricate MIPs, this strategy realized the goal of energy and cost saving while achieving simple synthesis of imprinted materials, and is expected to provide a new feasible idea to exploit synthetic methods for protein-MIPs.

Glucose conversion to 5-hydroxymethylfurfural with chromium exchanged bentonite and montmorillonite catalysts in different solvents

Synthesis of 5-hydroxymethylfurfural (HMF) was studied using Cr-montmorillonite and Cr-bentonite catalysts. Catalysts were characterized by Brunauer–Emmett–Teller surface area analyzer, X-ray diffraction (XRD), infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The effects of temperature and time on the conversion of glucose to HMF were investigated with different solvent-catalyst systems. HMF yield (45%) was obtained at 140 °C for 20 min using Cr-montmorillonite in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid. The 62.6% HMF yield was efficiently achieved at 150 °C for 10 min in [BMIM]Cl using Cr-bentonite. Cr-bentonite catalyst has good reusable properties in dimethyl sulfoxide (DMSO). The 94% of catalytic efficiency was maintained at the end of fifth use in DMSO.

Utilizing imidazole based ionic liquid as an environmentally friendly process for enhancement of the epoxy coating/graphene oxide composite corrosion resistance

The impact of 1-Butyl-3-methylimidazolium chloride (BMIM-Cl) ionic liquid for effective graphene oxide (GO) nanosheets dispersion improvement in the epoxy coating was studied. The BMIM-Cl adsorption on the GO sheets was investigated by Fourier transform infrared spectroscopy, X-ray diffraction analysis and UV–vis spectroscopy. The effect of GO-BMIM-Cl on the corrosion resistance of the epoxy coating was studied by EIS and salt spray test. In addition, the inhibition role of BMIM-Cl toward mild steel corrosion in saline solution was evaluated by EIS and polarization test. Results confirmed that the BMIM-Cl adsorption on the GO surface significantly enhanced the epoxy coating protection properties.

Preparation of copper–silver alloy with different morphologies by a electrodeposition method in 1-butyl-3-methylimidazolium chloride ionic liquid

Electrodeposition of a copper–silver alloy based on a 1-butyl-3-methylimidazolium chloride (BMIC) ionic liquid was studied. The electrochemical behaviour of copper and silver ions was characterized by cyclic voltammogram. The morphologies and phase compositions of copper–silver alloy coating under different electrodeposition conditions were investigated by scanning electron microscopy and X-ray diffraction. The results show that copper–silver alloys with different micro-morphologies can be obtained under different potential conditions in BMIC. Co-deposition of the copper–silver alloy followed a two-step reduction process, the first step is the reduction of the cupric ion to the cuprous ion and the second step is the simultaneous reduction of the cuprous ion and the silver ion to form an alloy. A dendritic alloy can be obtained at − 0.60 V, a bract alloy can be obtained at − 0.80 V and a granular alloy can be obtained at − 1 V. The coating particle size at \(60^{\circ }\hbox {C}\) was smaller than the particle size obtained at \(40^\circ \hbox {C}\). The Cu–Ag alloy prepared by electrodeposition in ionic liquids consists of single-phase copper and single-phase silver.

Effect of gold and iron nanoparticles on photocatalytic behaviour of titanium dioxide towards 1-butyl-3-methylimidazolium chloride ionic liquid

The high water solubility, chemical stability and low volatility of ionic liquids (ILs) have made them potentially persistent than conventional pollutants and toxic to the aquatic organisms. Therefore, extensive research efforts are being directed with an aim to develop cheap and efficient protocols to reduce the uncontrolled release of ILs in the environment. In the same line of action, titanium dioxide (TiO2) loaded with gold and iron nanoparticles were trialled for the photocatalytic degradation of highly concentrated 1-butyl-3-methylimidazolium chloride [BmimCl] ionic liquid. Furthermore, results pertaining to the degradation of the [BmimCl] using TiO2 loaded with gold nanoparticles (AuNPs) were compared with results obtained by using TiO2 loaded with Fe (NO3)3.9H2O and pristine TiO2 under same set of conditions. It was found that TiO2 decorated AuNPs demonstrated 7 times higher photocatalytic degradation for highly concentrated [BmimCl] in 60 min of reaction time in comparison to the pristine TiO2. Congruently, investigations also revealed that TiO2 loaded AuNPs expressed 3.3 times higher photocatalytic degradation of [BmimCl] in comparison to conventional photocatalyst TiO2@Fe under same reaction conditions. The higher photocatalytic performance associated with TiO2 loaded AuNPs was due to the enhanced Schottky barrier, which could have minimized the photocharge carrier resistance separation and migration. The mechanism for photocatalytic degradation of [BmimCl] using TiO2 loaded AuNPs has been also been described.

Synergistic effects of multiple functional ionic liquid-treated PEDOT:PSS and less-ion-defects S-acetylthiocholine chloride-passivated perovskite surface enabling stable and hysteresis-free inverted perovskite solar cells with conversion efficiency over 20%

The surface defects and grain boundary defects of organometallic halide perovskite films are detrimental to both the efficiency and stability of perovskite solar cells (PSCs). Furthermore, the electrical conductivity, work function and surface morphology of the hole transport layer (HTL) can also affect the performance of PSCs significantly. Here, we first have developed a novel synergistic strategy that uses multiple functional EMIC (1-Ethyl-3-methylimidazolium chloride) ionic liquid to modify PEDOT:PSS (poly (3, 4-ethylenedioxythiophene) polystyrene sulfonate) HTL, thereby obtaining the HTL with high electrical conductivity, low work function and smooth surface. Moreover, a novel S-acetylthiocholine chloride molecule which replaces expensive PCBM (phenyl-C61-butyric acid methyl ester) is developed to effectively passivate the negative- and positive-charged ionic defects in hybrid perovskite. The synergistic strategy extends the carrier recombination lifetime and reduces the charge trap density. In addition, the current hysteresis of the inverted device was also effectively eliminated. As a result, the champion cell in small area shows 20.06% efficiency with no hysteresis, along with an efficiency 18.77% for inverted PSCs in an active area of 1 cm2, both of which are the highest efficiency in the one-step PEDOT:PSS-based inverted PSCs so far. Compared to PCBM, the device passivated by S-acetylthiocholine chloride also has improved environmental stability (retaining 85% of initial PCE after 35 days storage without encapsulation in air with 60% humidity) and thermal stability (retaining 87% of initial PCE after 80 °C for 24 h storage without encapsulation under inert atmosphere).

Ion dissociation in aqueous 1-alkyl-3-methyl-imidazolium chlorides and the impact of microstructure formation

ABSTRACTWe study ion dissociation in four aqueous 1-alkyl-3-methyl-imidazolium chloride ([amim][Cl]) (where a = alkyl) ionic liquids (ILs) focusing on the effects of microstructure formation. We calculate ion dissociation using precise density, viscosity, and ionic conductivity measurements taken in this work as well as values reported by Rogac et al. (M. Bešter-Rogač, M. V. Fedotova, S.E. Kruchinin, and M. Klähn, Mobility and association of ions in aqueous solutions: The case of imidazolium based ionic liquids, Phys. Chem. Chem. Phys. 18, 28594–28605 (2016); R. Toma, A. Tot, J. Kuhar, and M. Be, Interactions in aqueous solutions of imidazolium chloride ionic liquids [C n mim][Cl] (n=0, 1, 2, 4, 6, 8) from volumetric properties, viscosity B-coefficients and molecular dynamics simulations, 254, 267–271 (2018)) in conjunction with our estimation framework presented previously (O. Nordness, L.D. Simoni, M.A. Stadtherr, and J.F. Brennecke, Characterization of Aqueous 1-Ethyl-3-Methylimidazolium Ionic Liquids for Calculation of Ion Dissociation, J. Phys. Chem. B 123, 1348–1358 (2019); L.D. Simoni, Predictive Modeling of Fluid Phase Equilibria for Systems Containing Ionic Liquids (University of Notre Dame, Notre Dame, IN, 2009)). We first consider ion dissociation at dilute IL concentrations below the critical aggregate concentrations . We introduce a combined Stokes radii term calculated from limiting molar conductivity data, which more accurately estimates ion dissociation in dilute IL systems than radii estimated from a group contribution method. Incorporating the new radii term in the existing model, we study ion dissociation across a wide IL concentration range. Even if prior knowledge of aggregation were not available, as is the case for aqueous [amim][Cl] systems, aggregation is apparent from this analysis because the increased viscous forces of microstructure formation lead to unrealistic estimates of ion dissociation.

Correlating Lipid Membrane Permeabilities of Imidazolium Ionic Liquids with their Cytotoxicities on Yeast, Bacterial, and Mammalian Cells.

Alkyl-imidazolium chloride ionic liquids (ILs) have been broadly studied for biochemical and biomedical technologies. They can permeabilize lipid bilayer membranes and have cytotoxic effects, which makes them targets for drug delivery biomaterials. We assessed the lipid-membrane permeabilities of ILs with increasing alkyl chain lengths from ethyl to octyl groups on large unilamellar vesicles using a trapped-fluorophore fluorescence lifetime-based leakage experiment. Only the most hydrophobic IL, with the octyl chain, permeabilizes vesicles, and the concentration required for permeabilization corresponds to its critical micelle concentration. To correlate the model vesicle studies with biological cells, we quantified the IL permeabilities and cytotoxicities on different cell lines including bacterial, yeast, and ovine blood cells. The IL permeabilities on vesicles strongly correlate with permeabilities and minimum inhibitory concentrations on biological cells. Despite exhibiting a broad range of lipid compositions, the ILs appear to have similar effects on the vesicles and cell membranes.

Physiological responses of Chlorella pyrenoidosa to 1-hexyl-3-methyl chloride ionic liquids with different cations

Ionic liquids (ILs) are massively used in multiple fields of industry, and consequently, they have entered the environment and become potential threats to the respective ecosystems. In this paper, the toxicity of two different cationic types of ILs (1-hexyl-3-methyl pyridine chloride ([C6Py]Cl) and 1-hexyl-3-methyl imidazole chloride ([C6MIM]Cl)) to Chlorella pyrenoidosa (C. pyrenoidosa) was investigated. Growth inhibition increased with increasing ILs concentrations. C. pyrenoidosa showed a certain recovery at low ILs concentrations, the growth inhibition decreased from 6.13% to 1.57% of the control from 24 h to 96 h, respectively, in 0.5 mg/L [C6MIM]Cl treatment. However, growth inhibition was negatively related with exposure time at high concentrations, and the strongest toxic effects were observed after 48 h. The IC50 values (half inhibitory concentration) were 8.47, 6.65, 6.91 and 7.11 mg/L of [C6MIM]Cl, respectively, in 24, 48, 72, and 96 h, and were 9.05, 6.83, 7.79 and 8.14 mg/L of [C6Py]Cl, respectively. Chlorophyll content declined with higher concentrations of the ILs. The values of chlorophyll fluorescence parameters: the maximum effective quantum yield of photosystem II (PSII) (Fv/Fm), maximum quantum yield in PSII (Fv/F0), and photosynthetic efficiency in PSII (Y(II)), decreased, whereas the minimal fluorescence (F0) increased following the ILs treatment, indicating damage to the photosystem II. [C6MIM]Cl and [C6Py]Cl caused deformation of algae cells, plasmolysis, and damage of the cell membrane and cell wall, and affected organelle structure. Reactive oxygen species (ROS) concentrations increased with higher ILs concentrations from, and superoxide dismutase and catalase activity first increased and then decreased, indicating that the antioxidant defense system was activated to counteract ROS. ROS was the main stress in C. pyrenoidosa induced by ILs, and compared with [C6Py]Cl, [C6MIM]Cl were more toxic to C. pyrenoidosa.

Impact of Tetrazolium Ionic Liquid Thermal Decomposition in Solvothermal Reaction on the Remarkable Photocatalytic Properties of TiO2 Particles.

Ionic liquids (ILs) could serve as a structuring agent, a solvent, or a source of dopant during solvothermal synthesis of semiconductors particles. To understand the role of IL during formation of TiO2 particles, it is necessary to study the stability of this IL in solvothermal synthesis conditions, as well as studying the surface properties of formed TiO2 particles. In view of this, the effect of the 2,3,5-triphenyltetrazolium chloride IL ([TPTZ][Cl]) thermal decomposition during the solvothermal reaction and IL content in the reaction system on photoactivity of TiO2 microparticles has been systematically investigated. The samples obtained by using [TPTZ][Cl] exhibited remarkable photocatalytic properties in phenol degradation reaction under visible light. HPLC analysis of the solvothermal reaction medium and X-ray photoelectron spectroscopy (XPS) analysis of TiO2 particles revealed that [TPTZ][Cl] was decomposed completely and was incorporated into the TiO2 lattice. Generally, increasing the reaction time (1, 4, 12, and 24 h) promoted the TiO2 microspheres formation, as well as raising the visible light-induced photocatalytic activity of the photocatalysts. Longer reaction time was also accompanied by an increase in the efficiency of 2,3,5-triphenyltetrazolium chloride decomposition. The properties of the photocatalysts were investigated by means of UV-VIS diffuse reflectance spectroscopy (DRS), BET surface area measurements, scanning electron microscopy (SEM), X-ray powder diffraction (XRD) analysis, and XPS.

Hollow fibre membrane-based liquid desiccant humidity control for controlled environment agriculture

Humidity control is an important factor affecting the overall sustainability, productivity, and energy efficiency of controlled environment agriculture. Liquid desiccants offer the potential for pinpoint control of humidity levels in controlled environments. In the present work, a dehumidification processes utilizing liquid desiccants pumped through the lumens of triple-bore PVDF hollow fibre membranes is implemented in a bench scale controlled environment agriculture system. Hydrophobic hollow fibre membranes were combined into an array and placed near the crops. Concentrated magnesium chloride liquid desiccant solution with a low vapour pressure was pumped through the hollow fibre lumens. The dehumidification permeance rate responded dynamically to the changing transpiration rate of the plants, as influenced by changes in environmental factors such as light, temperature, and vapour pressure. The dehumidification permeance rate increased from an average of 0.26–0.31 g m−2 h−1 Pa−1 as the velocity of the liquid desiccant through the hollow fibres increased from 0.023 to 0.081 m s−1. Humidity levels were targeted to be maintained within a range of 70–90% relative humidity at 23 °C. The membrane-based liquid desiccant system was demonstrated to successfully control humidity within a bench-scale controlled environment agricultural setup.

Detection of sodium aerosol using laser induced breakdown spectroscopy

Analysis of sodium aerosol is very important in various field including nuclear power station, electronic industry, and medical field. In medical field, aerosol detection can be employed to earlier detection of disease based on liquid in human being. In this present work, aerosol sodium detection has been performed using laser-induced breakdown spectroscopy (LIBS) utilizing pulse Nd:YAG laser. In the study, sodium aerosol made of sodium chloride (NaCl) liquid was deposited on a copper (Cu) metal plate. The Cu plate functions as a metal subtarget to initiate a plasma emission and to improve the emission intensity of sodium line. Experimentally, a pulse laser Nd YAG (1064 nm, 7 ns, dan 45 mJ) was focused on a sodium aerosol to induce a luminous plasma. The plasma was then sent into the spectrometer to obtain the emission spectrum of sodium. The observed sodium aerosol samples were made in five variations based on their various molarities (concentrations). Variations are made, ranging from 1 molar to 3 molar with the difference of each sample of 0.5 molar. Sharp Na lines at 588.9 nm and 589.3 nm, which overlap due to low resolution of spectrometer were clearly detected. The other lines coming from Cu subtarget occurs at 324.7 nm and 327.4 nm. Detail study of sodium analysis using laser induced breakdown spectroscopy will be presented.