- Corrosion Behavior and Mechanism of Basalt Fibers in Sodium Hydroxide Solution. [Journal Article]
- MMaterials (Basel) 2018 Aug 08; 11(8)
- In this paper, the corrosion mechanism and tensile properties of basalt fibers in sodium hydroxide (NaOH) solution with various concentrations and temperatures were studied. The hydroxyl ions disrupt...
In this paper, the corrosion mechanism and tensile properties of basalt fibers in sodium hydroxide (NaOH) solution with various concentrations and temperatures were studied. The hydroxyl ions disrupt the ⁻Si⁻O⁻Si⁻ and ⁻Si⁻O⁻Al⁻ bonds leading to the formation of insoluble hydroxides. With the continuation of the hydration reaction, a hydration layer (corrosion shell) with high content of calcium, iron, manganese and titanium ions was formed on the fiber surface. The corrosion shell enabled an increase in the strength and elongation at break of basalt fibers, significantly. Results showed that the tensile strength of fibers was strongly dependent on temperature and concentration. After the basalt fibers were immersed in 1 mol/L NaOH solution at 50 °C for 1 h, 3 h, 6 h, 1 day and 3 days, their retention ratios of strength were 67.6%, 57.8%, 52.5%, 49.0%, 58.2%, respectively. Higher temperature accelerated the corrosion rate of basalt fibers, shortened the formation time of the corrosion shell and increased mass loss. From 25 to 70 °C, the mass loss of fibers increased from 2.4% to 33.8% for fibers immersed in 1 mol/L NaOH for 3 days. The experimental results from quantitative x-ray fluorescence (XRF) showed that the mass loss of basalt fibers was mainly due to the leaching of silicon, aluminum and potassium ions.
- [Effect of cigarette smoke exposure on the expression of CCR7 and levels of Th1/Th2 cytokines in asthmatic rats]. [Journal Article]
- ZYZhonghua Yi Xue Za Zhi 2018 Jul 24; 98(28):2264-2268
- Objective: To investigate the effect of cigarette smoke exposure on the expression of CC Chemokine receptor 7 (CCR7) and levels of Th1/Th2 cytokines in asthmatic rats. Methods: Forty Wistar rats we...
Objective: To investigate the effect of cigarette smoke exposure on the expression of CC Chemokine receptor 7 (CCR7) and levels of Th1/Th2 cytokines in asthmatic rats. Methods: Forty Wistar rats were randomly divided into four groups: control group, asthma group, smoke exposure group, asthma-smoke exposure group. The asthma group were sensitized with ovalbumin (OVA) and Aluminum hydroxide at day 1, 8 and challenged with OVA at day 15 by atomization for 8 weeks.While control group was sensitized and challenged with normal saline instead of OVA.The smoke exposure group was sensitized and challenged with normal saline instead of OVA followed passive smoking for 8 weeks. The asthma-smoke exposure group was challenged with OVA followed passive smoking. The pathological changes of different groups were observed by HE-staining. CCR7 was semiquantitatively analyzed in lungs by immunohistochemistry.The concentration of CC chemokine ligand (CCL)19, CCL21, interferon (IFN)-γ and interleukin (IL)-4 in peripheral blood and CCL19 and CCL21 in bronchoalveolar lavage fluid (BALF) were measured by enzyme-linked immunosorbent (ELESA) assay. Results: In asthma group, smoke exposure group and asthma-smoke exposure group, the various degrees of inflammatory reaction appeared in lung tissue and the asthma-smoke exposure group was with the most significant reaction. In the lung tissues of the rats from asthma group, smoke exposure group and asthma-smoke exposure group, the average optical density (AOD) of CCR7 were significantly higher than those in control group (0.350±0.023, 0.252±0.022, 0.400±0.029 vs 0.180±0.020, all P<0.01). The AOD of CCR7 of asthma-smoke exposure group was much higher than both that in asthma group and in smoke exposure group (both P<0.01). In asthma group, smoke exposure group and asthma-smoke exposure group, the concentrations of both CCL19 and CCL21 in peripheral blood and BALF were significantly higher than that in control group (all P<0.01). The concentrations of both CCL19 and CCL21 in peripheral blood and BALF of asthma-smoke exposure group were significantly higher than the results in asthma group and in smoke exposure group (all P<0.01). The concentrations of IFN-γ in peripheral blood of asthma group and asthma-smoke exposure group were lower than those in control group [(33±3), (17±3) vs (70±4) pg/ml], but asthma-smoke exposure group was much lower than the results in asthma group (all P<0.01). The concentration of IFN-γ in peripheral blood of smoke exposure group[(100±5)pg/ml]was higher than that in control group and asthma-smoke exposure group (both P<0.01). In asthma group, smoke exposure group, asthma-smoke exposure group, the concentrations of IL-4 in peripheral blood were significantly higher than those in control group [(54±4), (42±4), (76±4) vs (30±4) pg/ml, all P<0.01]. The concentrations of IL-4 in peripheral blood of asthma-smoke exposure group was significantly higher than those in asthma group and in smoke exposure group (both P<0.01). Conclusion: Cigarette smoke could enhance the expression of CCR7 and its ligand, and it can also result in exacerbations of asthma by reducing the expression level of IFN-γ (the representative of Th1 cytokine) and increasing the expression level of IL-4 (the representative of Th2 cytokine).
- Crumpled Aluminum Hydroxide Nanostructures as a Microenvironment Dysregulation Agent for Cancer Treatment. [Journal Article]
- NLNano Lett 2018 Aug 02
- Owing to their unique physicochemical properties, nanomaterials have become a focus of multidisciplinary research efforts including investigations of their interactions with tumor cells and stromal c...
Owing to their unique physicochemical properties, nanomaterials have become a focus of multidisciplinary research efforts including investigations of their interactions with tumor cells and stromal compartment of tumor microenvironment (TME) toward the development of next-generation anticancer therapies. Here, we report that agglomerates of radially assembled Al hydroxide crumpled nanosheets exhibit anticancer activity due to their selective adsorption properties and positive charge. This effect was demonstrated in vitro by decreased proliferation and viability of tumor cells, and further confirmed in two murine cancer models. Moreover, Al hydroxide nanosheets almost completely inhibited the growth of murine melanoma in vivo in combination with a minimally effective dose of doxorubicin. Our direct molecular dynamics simulation demonstrated that Al hydroxide nanosheets can cause significant ion imbalance in the living cell perimembranous space through the selective adsorption of extracellular anionic species. This approach to TME dysregulation could lay the foundation for development of novel anticancer therapy strategies.
- Evaluation of intranasal and subcutaneous route of immunization in neonatal mice using DODAB-BF as adjuvant with outer membrane vesicles of Neisseria meningitis B. [Journal Article]
- IImmunobiology 2018 Jul 19
- CONCLUSIONS: Our findings indicate that DODAB-BF can be an alternative adjuvant for mucosal cell activation with OMVs of N. meningitidis B and that DODAB-BF was similar to aluminum hydroxide as an adjuvant for subcutaneous immunization.
- Dilodendron bipinnatum Radlk. ameliorates airway inflammation through multiple targets in a murine model of ovalbumin-induced allergic airway disease. [Journal Article]
- JEJ Ethnopharmacol 2018 Jul 25; 226:17-25
- CONCLUSIONS: These results somewhat agree on the popular use of the inner stem bark of D. bipinnatum as a treatment for allergic asthma. The HEDb exhibits significant anti-inflammatory activity in the OVA-induced mouse model of allergic asthma, possibly due to the down-regulation of the Th2 responses and LO inhibition, resulting in improvements in all analyzed inflammatory parameters.
- Evaluation of dried amorphous ferric hydroxide CFH-12® as agent for binding bioavailable phosphorus in lake sediments. [Journal Article]
- STSci Total Environ 2018 Jul 01; 628-629:990-996
- Metal hydroxides formed from aluminum (Al) and iron (Fe) salts can be used as phosphorus (P) adsorbents in lake restoration, but the application entails problems in low-alkaline lakes due to acid pro...
Metal hydroxides formed from aluminum (Al) and iron (Fe) salts can be used as phosphorus (P) adsorbents in lake restoration, but the application entails problems in low-alkaline lakes due to acid producing hydrolysis and potential formation of toxic metal ions. Therefore, we tested the potential of applying CFH-12® (Kemira) - a dried, amorphous Fe-oxide with no pH effect - in lake restoration. Since Fe3+ may become reduced in lake sediments and release both Fe2+ and any associated P we also evaluated the redox sensitivity of CFH-12® in comparison with freshly formed Fe(OH)3. CFH-12® was added to undisturbed sediment cores from three Danish lakes relative to the size of their mobile P pool (molar Fe:PMobile dose ratio of ~10:1), and P and Fe fluxes across the sediment-water interface were compared with those from untreated cores and cores treated with freshly formed Fe(OH)3. Under anoxic conditions, we found that CFH-12® significantly reduced the P efflux from the sediments (by 43% in Lake Sønderby, 70% in Lake Hampen and 60% in Lake Hostrup) while the Fe2+ efflux remained unchanged relative to the untreated cores. Cores treated with freshly formed Fe(OH)3 retained more P, but released significantly more Fe2+, indicating continued Fe3+ reduction. Finally, experiments with pure phases showed that CFH-12® adsorbed less P than freshly formed Fe(OH)3 in the short term, but was capable of adsorbing up to 70% of P adsorbed by Fe(OH)3 over 3months. With product costs only 30% higher than Al salts we find that CFH-12® has potential for use in restoration of low-alkaline lakes.
- Impact of crystalline and amorphous iron- and aluminum hydroxides on mechanisms of phosphate adsorption and desorption. [Journal Article]
- JEJ Environ Sci (China) 2018; 70:175-189
- Fourier-transform infrared (FT-IR) spectroscopic experiments were carried out during phosphate adsorption on highly crystalline gibbsite, poorly crystalline 2-line-ferrihydrite and amorphous iron-alu...
Fourier-transform infrared (FT-IR) spectroscopic experiments were carried out during phosphate adsorption on highly crystalline gibbsite, poorly crystalline 2-line-ferrihydrite and amorphous iron-aluminum-hydroxide mixtures in the molar ratio 1:0, 10:1, 5:1, 1:1, 1:5, 1:10 and 0:1. The OH stretching vibrational bands were utilized to analyze changes in structural and surface OH groups during adsorption, because the position of characteristic PO vibrational bands can shift depending on reaction conditions, pH or adsorbed phosphate content. Adsorption and desorption kinetics were studied at pH6 and different initial phosphate concentrations to achieve varying phosphate coverage on the mineral surfaces. For gibbsite the formation of AlHPO4 and Al2HPO4 can be assumed, while for ferrihydrite, a FeHPO4 or Fe2PO4 complex and the precipitation of FePO4 with longer equilibration time were proposed. Fe2HPO4 or a Fe2PO4 surface complex was deduced for Fe-hydroxides, an AlH2PO4 surface complex was identified for Al-hydroxide, and both displayed either hydrogen bonds to neighboring hydroxyl groups or hydrogen bonds to outer-sphere complexes. Fe:Al-hydroxide mixtures with high Al ratios showed a low phosphate desorption rate, while ferrihydrite and the Fe:Al-hydroxide mixtures with high Fe ratios had almost negligible desorption rates. It was concluded that within the weakly associated amorphous FeO(OH) materials, FePO4 precipitated, which was bound by outer-sphere hydrogen bonds. With high Al ratios, desorption increased, which indicated weaker phosphate binding of both inner-sphere and outer-sphere complexes and hence, either no or minor quantities of precipitate. Ferrihydrite showed a more rigid structure and a lower extent of precipitation compared to amorphous Fe-hydroxide.
- In Situ 27Al NMR Spectroscopy of Aluminate in Sodium Hydroxide Solutions above and below Saturation with Respect to Gibbsite. [Journal Article]
- ICInorg Chem 2018 Jul 23
- Aluminum hydroxide (Al(OH)3, gibbsite) dissolution and precipitation processes in alkaline environments play a commanding role in aluminum refining and nuclear waste processing, yet mechanistic aspec...
Aluminum hydroxide (Al(OH)3, gibbsite) dissolution and precipitation processes in alkaline environments play a commanding role in aluminum refining and nuclear waste processing, yet mechanistic aspects underlying sluggish kinetics during crystallization have remained obscured due to a lack of in situ probes capable of isolating incipient ion pairs. At a molecular level Al is cycling between tetrahedral ( T d) coordination in solution to octahedral ( O h) in the solid. We explored dissolution of Al(OH)3 that was used to produce variably saturated aluminate (Al(OH)4-)-containing solutions under alkaline conditions (pH >13) with in situ 27Al magic angle spinning (MAS)-nuclear magnetic resonance (NMR) spectroscopy, and interrogated the results with ab initio molecular dynamics (AIMD) simulations complemented with chemical shift calculations. The collective results highlight the overall stability of the solvation structure for T d Al in the Al(OH)4- oxyanion as a function of both temperature and Al concentration. The observed chemical shift did not change significantly even when the Al concentration in solution became supersaturated upon cooling and limited precipitation of the octahedral Al(OH)3 phase occurred. However, subtle changes in Al(OH)4- speciation correlated with the dissolution/precipitation reaction were found. AIMD-informed chemical shift calculations indicate that measurable perturbations should begin when the Al(OH)4-···Na+ distance is less than 6 Å, increasing dramatically at shorter distances, coinciding with appreciable changes to the electrostatic interaction and reorganization of the Al(OH)4- solvation shell. The integrated findings thus suggest that, under conditions incipient to and concurrent with gibbsite crystallization, nominally expected contact ion pairs are insignificant and instead medium-range (4-6 Å) solvent-separated Al(OH)4-···Na+ pairs predominate. Moreover, the fact that these medium-range interactions bear directly on resulting gibbsite characteristics was demonstrated by detailed microscopic and X-ray diffraction analysis and by progressive changes in the fwhm of the O h resonance, as measured by in situ NMR. Sluggish gibbsite crystallization may arise from the activation energy associated with disrupting this robust medium-range ion pair interaction.
- Evaluation of phosphate ion adsorption from aqueous solution by nickel-aluminum complex hydroxides. [Journal Article]
- WSWater Sci Technol 2018; 2017(3):913-921
- We prepared a variety of nickel-aluminum complex hydroxides, investigated their physicochemical properties, and evaluated their ability to adsorb phosphate ions (the molar ratios of nickel to aluminu...
We prepared a variety of nickel-aluminum complex hydroxides, investigated their physicochemical properties, and evaluated their ability to adsorb phosphate ions (the molar ratios of nickel to aluminum, 1:2, 1:1, 2:1, 3:1, and 4:1, are referred to as NA12, NA11, NA21, NA31, and NA41). NA12 and NA11 have amorphous structures; their specific surface areas and the concentration of associated hydroxyl groups were greater than those of other adsorbents. The number of phosphate ions adsorbed onto NA12 and NA11 was greater than that onto other adsorbents. These results indicated that the phosphate ion adsorption is related to the specific surface area and the amount of hydroxyl groups. The adsorption isotherm data, and the effects of contact time and pH on the adsorption were investigated; our results implied that both the Freundlich equation model and the pseudo-second-order kinetic model describe the adsorption of phosphate ions by NA11. We showed that phosphate ions adsorbed onto NA11 can be desorbed by sodium hydroxide solution at different concentrations and that NA11 could be reused for at least three repeated cycles of phosphate ion adsorption and desorption. This study illustrates that NA11 has the potential for practical application as an adsorbent for phosphate ions from wastewater.
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- Three-dimensional layered double hydroxide membranes: fabrication technique, growth mechanism, and enhanced photocatalytic activity. [Journal Article]
- CCChem Commun (Camb) 2018 Jul 26; 54(61):8494-8497
- Novel three-dimensional ZnAl-LDH/AAO and NiAl-LDH/AAO membranes using porous anodic aluminum oxide (AAO) templates as a substrate and an Al3+ source were successfully fabricated via a simple precipit...
Novel three-dimensional ZnAl-LDH/AAO and NiAl-LDH/AAO membranes using porous anodic aluminum oxide (AAO) templates as a substrate and an Al3+ source were successfully fabricated via a simple precipitant-free in situ growth technique. These membranes with uniform layered double hydroxide (LDH) plates on the outer and inner surfaces exhibit enhanced activities in photocatalysis.