Increasing Gas Hydrate Formation Temperature for Desalination of High Salinity Produced Water with Secondary Guests

We suggest a new gas hydrate-based desalination process using water-immiscible hydrate formers; cyclopentane (CP) and cyclohexane (CH) as secondary hydrate guests to alleviate temperature requirements for hydrate formation. The hydrate formation reactions were carried out in an isobaric condition of 3.1 MPa to find the upper temperature limit of CO₂ hydrate formation. Simulated produced water (8.95 wt % salinity) mixed with the hydrate formers shows an increased upper temperature limit from −2 °C for simple CO₂ hydrate to 16 and 7 °C for double (CO₂ + CP) and (CO₂ + CH) hydrates, respectively. The resulting conversion rate to double hydrate turned out to be similar to that with simple CO₂ hydrate at the upper temperature limit. Hydrate formation rates (<i>R</i>_f) for the double hydrates with CP and CH are shown to be 22 and 16 times higher, respectively, than that of the simple CO₂ hydrate at the upper temperature limit. Such mild hydrate formation temperature and fast formation kinetics indicate increased energy efficiency of the double hydrate system for the desalination process. Dissociated water from the hydrates shows greater than 90% salt removal efficiency for the hydrates with the secondary guests, which is also improved from about 70% salt removal efficiency for the simple hydrates

Structural Transformation due to Co-Host Inclusion in Ionic Clathrate Hydrates

Structural Transformation due to Co-Host Inclusion in Ionic Clathrate Hydrate

Maximized Proton Conductivity of the HPF₆ Clathrate Hydrate by Structural Transformation

The unique and specific interaction of ionic guests with the surrounding cage framework might play a key role in promoting the electrochemical properties of ionic clathrate hydrates. In this work we focus on addressing (1) structural transformation simply due to an increase of water content, (2) structure-dependent ionic conductivity, (3) the existence of maximum ionic conductivity at a specific hydration number, and (4) proton migration through channels in the crystalline hydrate matrix. The melting temperature and ionic conductivity of hexafluorophosphoric acid hexahydrate (HPF6·6.0H2O) are found to be approximately 29.5 °C and 10−1 S·cm−1, respectively, showing that HPF6·6.0H2O possesses desirable features as a solid proton conductor

Experimental Measurement of Phase Equilibrium of Hydrate in Water + Ionic Liquid + CH₄ System

With the goal of discovering a more effective type of thermodynamic hydrate inhibitors (THIs), the phase equilibrium conditions of CH₄ hydrates were examined in the presence of morpholinium and piperidinium ionic liquids (ILs) at a mass fraction of 0.1. It was observed that the addition of ILs shifted the hydrate equilibrium conditions toward higher pressure and lower temperature compared with those of hydrates formed from pure water. Both cationic and anionic species influenced the equilibrium conditions of the CH₄ hydrate. The piperidinium ILs showed better inhibition effect than did the morpholinium ILs at the same species of counteranions. The result may be due to the more hydrophobic nature of piperidinium ILs, which have a higher affinity for CH₄ molecules. It was also seen that the inhibition effect of BF₄^– ions was stronger than that of Br^– ions for both piperidinium and morpholinium ILs. Thus, the inhibition effect became stronger in the order: <i>N</i>-ethyl-<i>N</i>-methylpiperidinium tetrafluoroborate ([EMPip]­[BF₄]) > <i>N</i>-ethyl-<i>N</i>-methylpiperidinium bromide ([EMPip]­[Br]) > <i>N</i>-ethyl-<i>N</i>-methylmorpholinium tetrafluoroborate ([EMMor]­[BF₄]) > <i>N</i>-ethyl-<i>N</i>-methylmorpholinium bromide ([EMMor]­[Br]). The best among these ILs had inhibition effectiveness comparable with ethylene glycol and triethylene glycol, which are used commercially as THIs

CO/R regulates HIF-1α stability via the PHD2-dependent pathway.

(A-B) Astrocytes were subjected to Ru/R or CO/R and further incubated with or without 0.5 μM Antimycin A (AMA) (n = 4), or 1 mM N-acetylcysteine (NAC) (n = 3) for 4 h. Indicated proteins were detected via western blotting. (C) Astrocytes were transfected with 50 nM control, AMPKα, or PHD2 siRNA and subjected to Ru/R or CO/R. Indicated proteins were detected via western blotting (n = 3). (D) Astrocytes were transfected with 50 nM control, ERRα or PGC-1α siRNA, and subjected to Ru/R or CO/R. Indicated proteins were detected via western blotting and quantified (n = 7). (E) Mitochondrial biogenesis was determined by staining with MitoTracker (n = 4). (F) Astrocytes were transfected with 50 nM of control, or HIF-1α siRNA, and subjected to Ru/R or CO/R. Indicated proteins were detected via western blotting (n = 4). *P P P < 0.001.</p

Schematic diagram indicating that the HO-1 metabolites stimulates the reciprocal circuit of HIF-1α/ERRα in mitochondrial biogenesis via the Ca²⁺-dependent signaling cascade in astrocytes.

LTCC = L-type Ca2+ channel.</p

CO/R induces HIF-1α stability via the Ca²⁺-mediated CaMKKβ/AMPKα pathway.

(A-C) Astrocytes were transfected with control or indicated siRNAs and subjected to Ru/R or CO/R. Target protein levels in whole cell lysate were detected via western blotting (n = 4). Target mRNA levels were detected by RT-PCR. (D) Cells were transfected with 50 nM control or AMPKα siRNA alone or in combination with 2 μg SIRT1 plasmid and subjected to Ru/R or CO/R. Protein levels were determined via western blotting (n = 3). t-SIRT1 indicates transfected SIRT1 protein, and HIF-1α protein levels were quantified (n = 3). **P < 0.01.</p

HO-1 and HIF-1α are expressed in the peri-infarct region of the ischemic mouse brain.

(A) Representative image of the TTC stained regions (a, contralateral region; b, peri-infarct region; c, infarct region) in a mouse subjected to 2 h ischemia and 24 h reperfusion (I/R) (n = 3 per group). (B) DAB staining observed as brown color in the peri-infarct region (b) in wild-type (WT) and HO-1+/- mice. Scale bars = 20 μm. (C) Expression of target proteins was determined in brain tissues using western blot analysis, and their levels were quantified (n = 5 per group). **P D) WT and HO-1+/- mice were subjected to I/R, and the brain sections (a, contralateral region; b, peri-infarct region; c, infarct region) were stained with the indicated antibodies (n = 4 per group). Images are representative from three individual tissues.</p

CO/R enhances oxygen consumption.

(A-D) Astrocytes were subjected to Ru/R or CO/R and further incubated with or without 0.5 μM Antimycin A (AMA), 2 mM EGTA, 10 μM Nifedipine, or 10 μM Compound C (Comp C) for 4 h. UT indicates untreated control cells. (A-B) Mitochondria oxygen consumption was detected by the Oxygen Consumption Rate Assay Kit, and the quantified graph was generated at 45 min (n = 5). (C) Mitochondrial oxygen consumption was detected by the Oxygen Consumption Rate Assay Kit (n = 5). (D) Mitochondrial biogenesis was determined by staining with MitoTracker (n = 5). (E-F) Astrocytes were transfected with 50 nM control, ERRα or PGC-1α siRNA, and subjected to Ru/R or CO/R. (E) Oxygen consumption was measured and quantified at 45 min (n = 7). (F) Indicated proteins were detected via western blotting. *P P < 0.01.</p

CO/R induces HIF-1α and ERRα expression via L-type Ca²⁺ channels.

(A) Astrocytes were transfected with 50 nM control or 50 nM HO-1 siRNA and subjected to Ru/R or CO/R. Indicated protein levels were analyzed using western blotting and quantified (n = 4). (B) Astrocytes were treated with or without 10 μM Hemin for the time indicated (n = 3). (C) Astrocytes were treated with 0, 5, or 10 μM Hemin for 8 h (n = 3). (D) Cells were transfected with pcDNA3.1 mock or a pcDNA3.1/HO-1 vector and further cultured in fresh medium for 24 h (n = 3). (E) Astrocytes were pretreated with or without 25 μM SnPP, then incubated with 25 μM CORM-2 (CO), 25 μM bilirubin (BR), and 25 μM FeCl (Fe2+) in the presence or absence of 2 mM EGTA for 6 h. HIF-1α levels were analyzed using western blotting and quantified (n = 5). (F) Astrocytes were pretreated with or without 25 μM SnPP, then incubated with 25 μM CORM-2 (CO) and 25 μM bilirubin (BR) in the presence or absence of 2 mM EGTA for 6 h (n = 4). (G) Cells were subjected to Ru/R or CO/R, followed by treatment with 10 μM nifedipine (N), 0.3 μM ω-Conotoxin GVIA (C), 0.3 μM ω-Agatoxin TK (A), or 0.3 μM SNX 482 (S) for 4 h. HIF-1α and ERRα protein levels were quantified (n = 7). (H) [Ca2+]i was detected using the calcium-sensitive dye Fluo-4 AM (n = 3). *P P < 0.01.</p