Phosphate was removed from aqueous environment by corundum-hollow-spheres supported caclined hydrotalcite (cHT) thin films. Mg-Al-CO3 hydrotalcite (HT) thin films were deposited on corundumhollow-sphere substrates by ...Phosphate was removed from aqueous environment by corundum-hollow-spheres supported caclined hydrotalcite (cHT) thin films. Mg-Al-CO3 hydrotalcite (HT) thin films were deposited on corundumhollow-sphere substrates by hydrothermal homogeneous precipitation at 120℃for 30-240 min and cHT thin films were obtained by annealing of the HT thin films at 500℃for 180 min. Their crystal phase, morphology and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).The results show that homogeneous, well-crystallized and hierarchical flower-like thin films were deposited firmly on the surface of the corundum. The mechanism of nucleation and growth of the HT thin films was fitted well with the anion coordination polyhedron growth unit model. To determine the absorption of phosphate by this adsorbent, different bed depth (10-30 cm) and flow rate (1.0-3.0 m L/min) were examined by column experiments. The highest removal efficiency of phosphate amounted to 98.5%under optimum condition (pH=7.2). The adsorption capacity increased as the bed depth increased and decreased as the flow rate increased.展开更多
A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition...A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition effect and mechanism were analyzed by scanning electron microscopy(SEM),X-ray diffraction(XRD), thermal performance analysis, in-situ diffuse reflectance infrared spectroscopy and temperature-programmed experiment. The results have shown that the inhibitor containing lanthanum can play a good inhibitory role in every stage of coal oxidation. During the slow oxidation of coal samples, the inhibitor containing lanthanum ions can slow down the oxidation process of coal and increase the initial temperature of coal spontaneous combustion. At the same time, because the hydroxyl groups in LDHs are connected with-COO-groups on the coal surface through hydrogen bonds, the stability of coal is improved. With the increase of temperature, LDHs can remove interlayer water molecules and reduce the surface temperature of coal. CO release rate of coal samples decreases significantly after adding inhibitor containing lanthanum element, and the maximum inhibition rate of the inhibitor is 58.1%.展开更多
In the present study, polyethersulfone based nanohybrid membranes were effectively fabricated by incorporating graphene oxide(GO) and hydrotalcite(HT) nanosheets into the membrane structure. HT was prepared to overcom...In the present study, polyethersulfone based nanohybrid membranes were effectively fabricated by incorporating graphene oxide(GO) and hydrotalcite(HT) nanosheets into the membrane structure. HT was prepared to overcome the irreversible agglomeration behavior of GO at a high concentration which affects the performance of the membranes. In particular, the shedding of HT in formamide provides a two-dimensional nanosheet with a higher positive charge density to prevent the restacking of GO nanosheets. Here, exfoliated GO and HT with different combinations(1:1, 1:2 and 1:3) were infused in the membrane matrix to treat lead-acid battery effluent effectively. Finally, the hybrid membranes were characterized for hydrophilicity, mechanical strength and pure water flux. In combination with the superior properties of GO and HT, the prepared hybrid membranes can be used as effectively to improve the separation and permeation performance. The phase inversion process eliminated the leaching of nanoparticles from the membrane matrix. The reusability of the hybrid membrane was achieved using0.1 mol·L^(-1)NaOH solution and reused without significant reduction in lead removal efficiency. The cost analysis of the membrane was also estimated from the lab study. Therefore, the present study suggested the selective and sustainable treatment of lead from a real-life effluent.展开更多
AIM To evaluate the effects of hydrotalcite combined with esomeprazole on gastric ulcer healing quality. METHODS Forty-eight patients diagnosed with gastric ulcer between June 2014 and February 2016 were randomly allo...AIM To evaluate the effects of hydrotalcite combined with esomeprazole on gastric ulcer healing quality. METHODS Forty-eight patients diagnosed with gastric ulcer between June 2014 and February 2016 were randomly alloc at e d t o t he c ombinat ion t he r apy gr oup or monotherapy group. The former received hydrotalcite combined with esomeprazole, and the latter received esomeprazole alone, for 8 wk. Twenty-four healthy volunteers were recruited and acted as the healthy control group. Endoscopic ulcer healing was observed using white light endoscopy and narrow band imaging magnifying endoscopy. The composition of collagen fibers, amount of collagen deposition, expression of factor Ⅷ and TGF-β1, and hydroxyproline content were analyzed by Masson staining, immunohistochemistry, immunofluorescent imaging and ELISA. RESULTS Following treatment, changes in the gastric microvascular network were statistically different between the combination therapy group and the monotherapy group(P < 0.05). There were significant differences(P < 0.05) in collagen deposition, expression level of Factor Ⅷ and TGF-β1, and hydroxyproline content in the two treatment groups compared with the healthy control group. These parameters in the combination therapy group were significantly higher than in the monotherapy group(P < 0.05). The ratio of collagen?Ⅰ?to collagen Ⅲ was statistically different among the three groups, and was significantly higher in the combination therapy group than in the monotherapy group(P < 0.05). CONCLUSION Hydrotalcite combined with esomeprazole is superior to esomeprazole alone in improving gastric ulcer healing quality in terms of improving microvascular morphology, degree of structure maturity and function of regenerated mucosa.展开更多
A series of Cu-Mg-Al hydrotalcites derived oxides with a(Cu+Mg)/Al mole ratio of 3 and varied Cu/Mg mole ratio(from 0.07 to 0.30) were prepared by co-precipitation and calcination methods, then they were introduced to...A series of Cu-Mg-Al hydrotalcites derived oxides with a(Cu+Mg)/Al mole ratio of 3 and varied Cu/Mg mole ratio(from 0.07 to 0.30) were prepared by co-precipitation and calcination methods, then they were introduced to the hydrogenation of furfural in aqueous-phase. Effects of Cu/Mg mole ratio, reaction temperature, initial hydrogen pressure, reaction time and catalyst amount on the conversion rate of furfural as well as the selectivity toward desired product cyclopentanol were systematically investigated. The conversion of furfural over calcined hydrotalcite catalyst with a Cu/Mg mole ratio of 0.2 was up to 98.5% when the reaction was carried out under 140 ?C and the initial hydrogen pressure of 4 MPa for 10 h, while the selectivity toward cyclopentanol was up to 94.8%. The catalysts were characterized by XRD and SEM. XRD diffraction of all the samples showed characteristic pattern of hydrotalcite with varied peak intensity as a result of different Cu content. The catalytic activity was improved gradually with the increase of Cu component in the hydrotalcite.展开更多
Herein,the relationship between the structure and base properties of Mg–Al hydrotalcite catalysts was comprehensively investigated in relation to heat treatment and rehydration processes,which are well known as memor...Herein,the relationship between the structure and base properties of Mg–Al hydrotalcite catalysts was comprehensively investigated in relation to heat treatment and rehydration processes,which are well known as memory effects of hydrotalcite.The structure of Mg–Al hydrotalcites changed from layered double hydroxide(LDH)to mixed metal oxide and subsequently to a spinel structure during heat treatment,and it was returned from mixed metal oxide to a LDH structure by rehydration.Based on various characterizations,we successfully proposed a detailed mechanism of memory effect.We also confirmed that the Mg–Al hydrotalcites had weak or strong base sites and that their base properties could be systematically tuned by heat treatment and rehydration.The prepared Mg–Al hydrotalcites were applied to a model reaction,isomerization of glucose to fructose,as base catalysts.Among the catalysts tested,the rehydrated Mg–Al hydrotalcite efficiently produced fructose due to its appropriate base and structure properties.We finally concluded that the base sites of Mg–Al hydrotalcites can be designed as desired by heat treatment and rehydration.Moreover,through systematic design of the base sites of Mg–Al hydrotalcites,these can be promising catalysts for various heterogeneous reactions over base catalysts,giving excellent catalytic performances.展开更多
Mg-Al hydrotalcites were synthesized using different preparation methods(a co-precipitation method, a urea method, and a simple one) to analyze their effect on the catalytic activity of these solid base catalysts. The...Mg-Al hydrotalcites were synthesized using different preparation methods(a co-precipitation method, a urea method, and a simple one) to analyze their effect on the catalytic activity of these solid base catalysts. The method strongly affected the structure of their layers(e.g., the growth and stacking of the layers, and the type of intercalated anions) and, accordingly, their catalytic activity. The Mg-Al hydrotalcite prepared by co-precipitation showed the best catalytic performance in the isomerization of glucose into fructose, due to the small crystallite size and sand rose morphology enhancing the exposure of surface active sites to reactants.展开更多
A new method for regulating the synthesis of Ni Mg Fe hydrotalcites(NMF LDHs) with the addition of hydroxyl compounds was proposed. A series of NMF LDHs were prepared by the above method, and then were calcined to obt...A new method for regulating the synthesis of Ni Mg Fe hydrotalcites(NMF LDHs) with the addition of hydroxyl compounds was proposed. A series of NMF LDHs were prepared by the above method, and then were calcined to obtain the Ni Mg FeOx(NMFOx) samples. The NMFOxsamples were characterized by XRD,SEM, TG-DTG, XPS and CO2-TPD, respectively. The catalytic performance of NMFOxfor depolymerizing calcium lignosulfonate(CLS) was evaluated by hydrothermal reaction. The results showed that the addition of hydroxyl compounds favored reducing the particle sizes of NMF LDHs. For the depolymerization of CSL, the yield of liquid product increased from 45% to 75.8% with the addition of NMFOx-ethanol(NMFOxET). The liquid products were mainly phenolics, aromatics, ketones and esters. The total selectivity of oxy-containing compounds was over 90.6%, among them, the phenolics were approximately 35.2%. The valence of Ni and Fe, crystalline phase and basicity almost remained unchanged. The NMFOx-ET samples were recycled for the depolymerization of CLS, moreover, the NMFOx-ET samples had high activity and stability after 4 cycles.展开更多
Mg/Al/Fe layered double hydroxide(MAF-LDH1) was prepared by solvothermal method with the sodium dodecyl sulfate as the template, and the ethanol system was benefit to growth of sample. The nature in the resulting MAF-...Mg/Al/Fe layered double hydroxide(MAF-LDH1) was prepared by solvothermal method with the sodium dodecyl sulfate as the template, and the ethanol system was benefit to growth of sample. The nature in the resulting MAF-LDH was investigated by X-ray diffraction, field emission scanning electron microscopy, Fourier transformed infrared spectra, thermogravimetric analysis, and N2 adsorption-desorption.The morphology of MAF-LDH1 is petal-like with the size of 400-500 nm and the thickness about 10-20 nm. The adsorption performance of the samples was evaluated by absorption of the Congo red(CR) solutions. Compared with Mg/Al layered double hydroxide(MA-LDH), the maximum adsorption capacities of the MAF-LDH1 samples were 943.4 mg/g which was greatly enhanced. Furthermore, after seven cycling tests, the adsorption performance was still up to 90%. Theoretical calculation results revealed that the adsorption process was spontaneous and followed the pseudo-second-order kinetic model and Freundlich model. This work provides a promising alternative strategy to enhance the adsorptive properties of hydrotalcite-like materials.展开更多
Cerium-based sealing treatment was developed for Mg-Al hydrotalcite film on AZ91D Mg alloy,and the influence of cerium salt solution was investigated to modify the surface integrity and corrosion resistance.Scanning e...Cerium-based sealing treatment was developed for Mg-Al hydrotalcite film on AZ91D Mg alloy,and the influence of cerium salt solution was investigated to modify the surface integrity and corrosion resistance.Scanning electron microscope(SEM)and X-ray diffraction(XRD)measurements were carried out to analyze the surface morphology and phase composition.The corrosion resistance of Mg-Al hydrotalcite film after sealing treatment was evaluated by the polarization curve and electrochemical impedance spectroscopy(EIS)tests.The results showed that lower concentration of Ce-containing solution was beneficial to seal the micro-cracks on Mg-Al hydrotalcite film,and improve the surface integrity and corrosion resistance;higher concentration of Ce-containing solution could seal fewer micro-cracks,and the corrosion resistance was decreased owing to the disintegration of Mg-Al hydrotalcite film.展开更多
Hydrotalcite can act as a co-stabilizer with other main stabilizer for poly(vinyl chloride)(PVC). The thermal stability and fluid property of PVC filled with hydrotalcite surface-treated with titanate and silane were ...Hydrotalcite can act as a co-stabilizer with other main stabilizer for poly(vinyl chloride)(PVC). The thermal stability and fluid property of PVC filled with hydrotalcite surface-treated with titanate and silane were studied in this work. Organic Sn is a main stabilizer and hydrotalcite is a stabilizing assistant. The stability of the PVC resin mixed with organic Sn and hydrotalcite is better than that of the PVC resin mixed with organic Sn alone. It is shown that the PVC resin filled with hydrotalcite possesses a better static and dynamic heat stability. Moreover, hydrotalcite can improve the fluid property of PVC, which is advantageous to the processing of PVC, and the optimum content of hydrotalcite is about 1%-2%(mass fraction).展开更多
Elevated-temperature pressure swing adsorption is a promising technique for producing high purity hydrogen and controlling greenhouse gas emissions. Thermodynamic analysis indicated that the CO in H_2-rich gas could b...Elevated-temperature pressure swing adsorption is a promising technique for producing high purity hydrogen and controlling greenhouse gas emissions. Thermodynamic analysis indicated that the CO in H_2-rich gas could be controlled to trace levels of below 10 ppm by in situ reduction of the CO_2 concentration to less than 100 ppm via the aforementioned process. The CO_2 adsorption capacity of potassiumpromoted hydrotalcite at elevated temperatures under different adsorption(mole fraction, working pressure) and desorption(flow rate, desorption time, steam effects) conditions was systematically investigated using a fixed bed reactor. It was found that the CO_2 residual concentration before the breakthrough of CO_2 mainly depended on the total amount of purge gas and the CO_2 mole fraction in the inlet syngas.The residual CO_2 concentration and uptake achieved for the inlet gas comprising CO_2(9.7 mL/min) and He(277.6 mL/min) at a working pressure of 3 MPa after 1 h of Ar purging at 300 mL/min were 12.3 ppm and0.341 mmol/g, respectively. Steam purge could greatly improve the cyclic adsorption working capacity, but had no obvious benefit for the recovery of the residual CO_2 concentration compared to purging with an inert gas. The residual CO_2 concentration obtained with the adsorbent could be reduced to 3.2 ppm after 12 h of temperature swing at 450 °C. A new concept based on an adsorption/desorption process, comprising adsorption, steam rinse, depressurization, steam purge, pressurization, and high-temperature steam purge, was proposed for reducing the steam consumption during CO/CO_2 purification.展开更多
CO2 adsorption on the surface of hydrotalcite-derived mixed oxide catalysts was investigated under low pressure glow discharge plasma in opercindo conditions via FT-IR spectroscopy.Nickel catalysts were promoted with ...CO2 adsorption on the surface of hydrotalcite-derived mixed oxide catalysts was investigated under low pressure glow discharge plasma in opercindo conditions via FT-IR spectroscopy.Nickel catalysts were promoted with various transition metal species(Ce,Fe,La,Zr)to influence their physico-chemical properties.Fe and Zr species were successfully incorporated into hydrotalcite brucite layers.After calcination formed a single phase with Ni(Mg,A1)O mixed oxide,while La and Ce species formed separate phases.This had a consequence in the distribution of surface basic sites as well as in the affinity to CO produced upon CO2 dissociation in plasma.Plasma treatment activated the surface of prepared materials and changed their properties via the generation of strong basic sites associated with low coordinated surface oxygen anions.Moreover,the CO2 adsorption capacity of prepared materials increased after plasma treatment.展开更多
In this study, Mg-Al-CO3 hydrotalcite was synthesized from a kaolinite as natural source aluminium using two simple methods. The first method uses the kaolinite in natural solid state, the second method use the filtra...In this study, Mg-Al-CO3 hydrotalcite was synthesized from a kaolinite as natural source aluminium using two simple methods. The first method uses the kaolinite in natural solid state, the second method use the filtrate of the kaolinite after dissolution by acidic solutions. The structure of the materials was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry (DSC) and Brunauer, Emmett, and Teller (BET) measurements.展开更多
The use of heterogeneous catalysts in the transesterification reaction of vegetable oils has getting emphasis in recent years, mainly by the alternative of obtaining clean fuel derived from renewable sources. Metal ox...The use of heterogeneous catalysts in the transesterification reaction of vegetable oils has getting emphasis in recent years, mainly by the alternative of obtaining clean fuel derived from renewable sources. Metal oxide such as MgO or CaO, supported ones like ?and zeolites are often applied in transesterification process. Among them, hydrotalcite has shown potential as catalysts on this reaction due to their physicochemical properties, such as: thermal stability, porosity, specific surface area, memory effect, basicity, acidity and anion exchange capacity. This work studies the catalytic performance of the calcium and aluminum based hydrotalcite in the transesterification reaction of soybean oil in methanol and ethanol. The hydrotalcite samples treated at 450?C were impregnated with KOH. The efficiency of impregnated and non- impregnated samples was compared and the non-impregnated one showed the best performance. This property was attributed to the higher availability of active sites used in the transesterification process.展开更多
Water pollution with dye chemicals from apparel industries is a serious problem in the world.Since most of dyes are potentially have toxic and carcinogenic effects on human,it is important to remove them before they a...Water pollution with dye chemicals from apparel industries is a serious problem in the world.Since most of dyes are potentially have toxic and carcinogenic effects on human,it is important to remove them before they are discharged to the environment.Among many methods available for dyes removal in water,adsorption is the easiest and economically feasible that has no major obstacle for practical applications.In the present study,we tested calcined Mg/Al hydrotalcite(Mg/Al CHT)prepared by coprecipitation technique as an adsorbent for the removal of Navy Blue(NB)and Yellow F3G(YF3G)dyes.Mg/Al CHT was characterized by using a Fourier transform infrared(FTIR)spectrometer,an X-ray diffractometer(XRD)and a scanning electron microscope(SEM).The results showed that Mg/Al CHT was highly effective as an adsorbent for the removal of NB and YF3G under mild-acidic condition(pH 4)with removal capacities(b)according to Langmuir isotherm model were 7.97×10^(–4) and 5.80×10^(–4)mol·g^(-1),respectively.Kinetics study showed that the adsorption of NB and YF3D on Mg/Al CHT followed pseudosecond order with rate constant(k_(p2))11.57×10^(3) and 11.75×103 g·mol^(-1)·min-1,respectively.The spent adsorbent can be easily regenerated by simply calcining it at 450℃ for 3 h.Adsorption test on the mixture of NB and YF3G showed that the adsorption capacity of Mg/Al CHT was eightfold higher than that of Mg/Al HT and the value was maintained with repeated use.展开更多
With the world’s fossil fuels being finite in nature,an increasing interest focuses on the application of alternative renewable resources such as biomass.Biomass-derived platform chemicals with abundant functional gr...With the world’s fossil fuels being finite in nature,an increasing interest focuses on the application of alternative renewable resources such as biomass.Biomass-derived platform chemicals with abundant functional groups have the potential to replace bulk chemicals for the production of value-added chemicals,fuels,and materials.The upgrading of these platform chemicals relies on the development of efficient catalytic systems.Hydrotalcite,with its wide compositional variety,tuneable anion-exchange capacity,and controlled acidity/basicity sites demonstrates great potential in the catalytic upgrading of biomass and the derived platform chemicals.The past decade has witnessed the emergence of research achievements on the development of efficient and robust hydrotalcite-derived metal catalysts and their applications in the upgrading of biomass or the derived platform chemicals.In this review,we aim to summarize the recent advances on the catalytic upgrading of biomass-derived platform chemicals(e.g.,furfural,5-hydroxymethylfurfural,levulinic acid,and glycerol)via hydrotalcitederived metal catalysts.We also observed that the crucial role of using hydrotalcite-derived catalysts relies on their strong metal–support interactions.As a result,a section focusing on the discussion of the metal–support interactions of hydrotalcitederived catalysts was provided.展开更多
Ni-Co bimetallic catalysts with different Ni/Co content were derived from cold plasma jet decomposition and reduction of hydrotalcite-like compounds containing Ni,Co,Mg and Al,and their catalytic performance was inves...Ni-Co bimetallic catalysts with different Ni/Co content were derived from cold plasma jet decomposition and reduction of hydrotalcite-like compounds containing Ni,Co,Mg and Al,and their catalytic performance was investigated with dry reforming of methane.Experimental results showed that the hydrotalcite-like precursors could be completely decomposed and partly reduced by cold plasma jet,and the Nicontained catalysts exhibited much higher activity than the catalyst without Ni.Especially,the catalyst with Ni/Co ratio of 8/2 achieved not only the highest conversions of 80.3%and 69.3%for CH4 and CO2,respectively,but also the best stability in 100 h testing.The catalysts were characterized by XRD,XPS,TEM and N2 adsorption techniques,and the results showed that the better performance of the 8Ni2Co bimetallic catalyst was attributed to its higher metal dispersion,smaller metal particle size,as well as the interaction effect between Ni and Co,which were brought by the special catalyst preparation method.展开更多
Ammonium containing catalyst Mg/Al/Cu-NH3·H2O hydrotalcite (HT) is prepared via co-precipitation, which is effective for NOx storage under 160℃. XRD and FT-IR are employed to characterize its structure and show ...Ammonium containing catalyst Mg/Al/Cu-NH3·H2O hydrotalcite (HT) is prepared via co-precipitation, which is effective for NOx storage under 160℃. XRD and FT-IR are employed to characterize its structure and show that ammonium is successfully incorporated into HT. Meanwhile, the HT still retains the typical structure of hydrotalcite-like compounds. NOx storage activity tests indicate Mg/Al/Cu-NH3·H2O HT shows the significant NOx removal activity at 156℃ with a little Oxygen existence. TGA and DTG reveal the reaction of the released ammonium with NOx and storage NOx as nitrates will be responsible for the high NOx storage activity. Additionally, the temperature programmed desorption test of NOx adsorbed sample under 175℃ proves NOx is stored successfully into Mg/Al/Cu-NH3·H2O HT further.展开更多
基金Supported by the Major Program of the Ministry of Education of the People’s Republic of China。
文摘Phosphate was removed from aqueous environment by corundum-hollow-spheres supported caclined hydrotalcite (cHT) thin films. Mg-Al-CO3 hydrotalcite (HT) thin films were deposited on corundumhollow-sphere substrates by hydrothermal homogeneous precipitation at 120℃for 30-240 min and cHT thin films were obtained by annealing of the HT thin films at 500℃for 180 min. Their crystal phase, morphology and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).The results show that homogeneous, well-crystallized and hierarchical flower-like thin films were deposited firmly on the surface of the corundum. The mechanism of nucleation and growth of the HT thin films was fitted well with the anion coordination polyhedron growth unit model. To determine the absorption of phosphate by this adsorbent, different bed depth (10-30 cm) and flow rate (1.0-3.0 m L/min) were examined by column experiments. The highest removal efficiency of phosphate amounted to 98.5%under optimum condition (pH=7.2). The adsorption capacity increased as the bed depth increased and decreased as the flow rate increased.
基金Funded by National Natural Science Foundation of China (No.52074218)。
文摘A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition effect and mechanism were analyzed by scanning electron microscopy(SEM),X-ray diffraction(XRD), thermal performance analysis, in-situ diffuse reflectance infrared spectroscopy and temperature-programmed experiment. The results have shown that the inhibitor containing lanthanum can play a good inhibitory role in every stage of coal oxidation. During the slow oxidation of coal samples, the inhibitor containing lanthanum ions can slow down the oxidation process of coal and increase the initial temperature of coal spontaneous combustion. At the same time, because the hydroxyl groups in LDHs are connected with-COO-groups on the coal surface through hydrogen bonds, the stability of coal is improved. With the increase of temperature, LDHs can remove interlayer water molecules and reduce the surface temperature of coal. CO release rate of coal samples decreases significantly after adding inhibitor containing lanthanum element, and the maximum inhibition rate of the inhibitor is 58.1%.
文摘In the present study, polyethersulfone based nanohybrid membranes were effectively fabricated by incorporating graphene oxide(GO) and hydrotalcite(HT) nanosheets into the membrane structure. HT was prepared to overcome the irreversible agglomeration behavior of GO at a high concentration which affects the performance of the membranes. In particular, the shedding of HT in formamide provides a two-dimensional nanosheet with a higher positive charge density to prevent the restacking of GO nanosheets. Here, exfoliated GO and HT with different combinations(1:1, 1:2 and 1:3) were infused in the membrane matrix to treat lead-acid battery effluent effectively. Finally, the hybrid membranes were characterized for hydrophilicity, mechanical strength and pure water flux. In combination with the superior properties of GO and HT, the prepared hybrid membranes can be used as effectively to improve the separation and permeation performance. The phase inversion process eliminated the leaching of nanoparticles from the membrane matrix. The reusability of the hybrid membrane was achieved using0.1 mol·L^(-1)NaOH solution and reused without significant reduction in lead removal efficiency. The cost analysis of the membrane was also estimated from the lab study. Therefore, the present study suggested the selective and sustainable treatment of lead from a real-life effluent.
文摘AIM To evaluate the effects of hydrotalcite combined with esomeprazole on gastric ulcer healing quality. METHODS Forty-eight patients diagnosed with gastric ulcer between June 2014 and February 2016 were randomly alloc at e d t o t he c ombinat ion t he r apy gr oup or monotherapy group. The former received hydrotalcite combined with esomeprazole, and the latter received esomeprazole alone, for 8 wk. Twenty-four healthy volunteers were recruited and acted as the healthy control group. Endoscopic ulcer healing was observed using white light endoscopy and narrow band imaging magnifying endoscopy. The composition of collagen fibers, amount of collagen deposition, expression of factor Ⅷ and TGF-β1, and hydroxyproline content were analyzed by Masson staining, immunohistochemistry, immunofluorescent imaging and ELISA. RESULTS Following treatment, changes in the gastric microvascular network were statistically different between the combination therapy group and the monotherapy group(P < 0.05). There were significant differences(P < 0.05) in collagen deposition, expression level of Factor Ⅷ and TGF-β1, and hydroxyproline content in the two treatment groups compared with the healthy control group. These parameters in the combination therapy group were significantly higher than in the monotherapy group(P < 0.05). The ratio of collagen?Ⅰ?to collagen Ⅲ was statistically different among the three groups, and was significantly higher in the combination therapy group than in the monotherapy group(P < 0.05). CONCLUSION Hydrotalcite combined with esomeprazole is superior to esomeprazole alone in improving gastric ulcer healing quality in terms of improving microvascular morphology, degree of structure maturity and function of regenerated mucosa.
基金supported by the National Hi-tech Research and Development Program of China(863 Program)(2012AA051801)the Fundamenta lResearch Funds for the Central Universities(No.CXZZ13 0112)
文摘A series of Cu-Mg-Al hydrotalcites derived oxides with a(Cu+Mg)/Al mole ratio of 3 and varied Cu/Mg mole ratio(from 0.07 to 0.30) were prepared by co-precipitation and calcination methods, then they were introduced to the hydrogenation of furfural in aqueous-phase. Effects of Cu/Mg mole ratio, reaction temperature, initial hydrogen pressure, reaction time and catalyst amount on the conversion rate of furfural as well as the selectivity toward desired product cyclopentanol were systematically investigated. The conversion of furfural over calcined hydrotalcite catalyst with a Cu/Mg mole ratio of 0.2 was up to 98.5% when the reaction was carried out under 140 ?C and the initial hydrogen pressure of 4 MPa for 10 h, while the selectivity toward cyclopentanol was up to 94.8%. The catalysts were characterized by XRD and SEM. XRD diffraction of all the samples showed characteristic pattern of hydrotalcite with varied peak intensity as a result of different Cu content. The catalytic activity was improved gradually with the increase of Cu component in the hydrotalcite.
基金supported by C1 Gas Refinery Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT&Future Planning(2015M3D3A1A01064908)supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.2015R1D1A1A01059724)。
文摘Herein,the relationship between the structure and base properties of Mg–Al hydrotalcite catalysts was comprehensively investigated in relation to heat treatment and rehydration processes,which are well known as memory effects of hydrotalcite.The structure of Mg–Al hydrotalcites changed from layered double hydroxide(LDH)to mixed metal oxide and subsequently to a spinel structure during heat treatment,and it was returned from mixed metal oxide to a LDH structure by rehydration.Based on various characterizations,we successfully proposed a detailed mechanism of memory effect.We also confirmed that the Mg–Al hydrotalcites had weak or strong base sites and that their base properties could be systematically tuned by heat treatment and rehydration.The prepared Mg–Al hydrotalcites were applied to a model reaction,isomerization of glucose to fructose,as base catalysts.Among the catalysts tested,the rehydrated Mg–Al hydrotalcite efficiently produced fructose due to its appropriate base and structure properties.We finally concluded that the base sites of Mg–Al hydrotalcites can be designed as desired by heat treatment and rehydration.Moreover,through systematic design of the base sites of Mg–Al hydrotalcites,these can be promising catalysts for various heterogeneous reactions over base catalysts,giving excellent catalytic performances.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education (NRF-2015R1D1A1A01059724)
文摘Mg-Al hydrotalcites were synthesized using different preparation methods(a co-precipitation method, a urea method, and a simple one) to analyze their effect on the catalytic activity of these solid base catalysts. The method strongly affected the structure of their layers(e.g., the growth and stacking of the layers, and the type of intercalated anions) and, accordingly, their catalytic activity. The Mg-Al hydrotalcite prepared by co-precipitation showed the best catalytic performance in the isomerization of glucose into fructose, due to the small crystallite size and sand rose morphology enhancing the exposure of surface active sites to reactants.
基金Supported by the Program for National Natural Science Foundation of China(No.51674089)Excellent Youth Foundation of Heilongjiang Province of China(No.JC2018002)+2 种基金Postdoctoral Scientific Research Development Fund of Heilongjiang Province of China(No.LBH-Q16037)the Youth Fund of Northeast Petroleum University(No.2018QNL-17)the Postgraduate Innovative Research Projects of Northeast Petroleum University(No.YJSCX2017-014NEPU)
文摘A new method for regulating the synthesis of Ni Mg Fe hydrotalcites(NMF LDHs) with the addition of hydroxyl compounds was proposed. A series of NMF LDHs were prepared by the above method, and then were calcined to obtain the Ni Mg FeOx(NMFOx) samples. The NMFOxsamples were characterized by XRD,SEM, TG-DTG, XPS and CO2-TPD, respectively. The catalytic performance of NMFOxfor depolymerizing calcium lignosulfonate(CLS) was evaluated by hydrothermal reaction. The results showed that the addition of hydroxyl compounds favored reducing the particle sizes of NMF LDHs. For the depolymerization of CSL, the yield of liquid product increased from 45% to 75.8% with the addition of NMFOx-ethanol(NMFOxET). The liquid products were mainly phenolics, aromatics, ketones and esters. The total selectivity of oxy-containing compounds was over 90.6%, among them, the phenolics were approximately 35.2%. The valence of Ni and Fe, crystalline phase and basicity almost remained unchanged. The NMFOx-ET samples were recycled for the depolymerization of CLS, moreover, the NMFOx-ET samples had high activity and stability after 4 cycles.
基金Funded by the Science and Technology Development Plan Project of Shandong Province,China(No.2013GSF11714)the Open Project of Hunan Sustentation Fund:Key Laboratory of Applied Environmental Photocatalysis,China(No.ccsu-KF-1501)
文摘Mg/Al/Fe layered double hydroxide(MAF-LDH1) was prepared by solvothermal method with the sodium dodecyl sulfate as the template, and the ethanol system was benefit to growth of sample. The nature in the resulting MAF-LDH was investigated by X-ray diffraction, field emission scanning electron microscopy, Fourier transformed infrared spectra, thermogravimetric analysis, and N2 adsorption-desorption.The morphology of MAF-LDH1 is petal-like with the size of 400-500 nm and the thickness about 10-20 nm. The adsorption performance of the samples was evaluated by absorption of the Congo red(CR) solutions. Compared with Mg/Al layered double hydroxide(MA-LDH), the maximum adsorption capacities of the MAF-LDH1 samples were 943.4 mg/g which was greatly enhanced. Furthermore, after seven cycling tests, the adsorption performance was still up to 90%. Theoretical calculation results revealed that the adsorption process was spontaneous and followed the pseudo-second-order kinetic model and Freundlich model. This work provides a promising alternative strategy to enhance the adsorptive properties of hydrotalcite-like materials.
基金supported by the National Natural Science Foundation of China(No.51701093)the Natural Science Foundation of Jiangsu Province(No.BK20170764)+2 种基金the Six Talent Peaks(No.2015-XCL-025)the Qing Lan Project of Jiangsu Province,the Practice Innovation Program for graduate students of Jiangsu Province(No.SJZZ16_0292)the Research Fund of Nanjing Institute of Technology(No.JCYJ201603).
文摘Cerium-based sealing treatment was developed for Mg-Al hydrotalcite film on AZ91D Mg alloy,and the influence of cerium salt solution was investigated to modify the surface integrity and corrosion resistance.Scanning electron microscope(SEM)and X-ray diffraction(XRD)measurements were carried out to analyze the surface morphology and phase composition.The corrosion resistance of Mg-Al hydrotalcite film after sealing treatment was evaluated by the polarization curve and electrochemical impedance spectroscopy(EIS)tests.The results showed that lower concentration of Ce-containing solution was beneficial to seal the micro-cracks on Mg-Al hydrotalcite film,and improve the surface integrity and corrosion resistance;higher concentration of Ce-containing solution could seal fewer micro-cracks,and the corrosion resistance was decreased owing to the disintegration of Mg-Al hydrotalcite film.
文摘Hydrotalcite can act as a co-stabilizer with other main stabilizer for poly(vinyl chloride)(PVC). The thermal stability and fluid property of PVC filled with hydrotalcite surface-treated with titanate and silane were studied in this work. Organic Sn is a main stabilizer and hydrotalcite is a stabilizing assistant. The stability of the PVC resin mixed with organic Sn and hydrotalcite is better than that of the PVC resin mixed with organic Sn alone. It is shown that the PVC resin filled with hydrotalcite possesses a better static and dynamic heat stability. Moreover, hydrotalcite can improve the fluid property of PVC, which is advantageous to the processing of PVC, and the optimum content of hydrotalcite is about 1%-2%(mass fraction).
基金financed by Shanxi Province Science and Technology Major Projects of MH2015-06
文摘Elevated-temperature pressure swing adsorption is a promising technique for producing high purity hydrogen and controlling greenhouse gas emissions. Thermodynamic analysis indicated that the CO in H_2-rich gas could be controlled to trace levels of below 10 ppm by in situ reduction of the CO_2 concentration to less than 100 ppm via the aforementioned process. The CO_2 adsorption capacity of potassiumpromoted hydrotalcite at elevated temperatures under different adsorption(mole fraction, working pressure) and desorption(flow rate, desorption time, steam effects) conditions was systematically investigated using a fixed bed reactor. It was found that the CO_2 residual concentration before the breakthrough of CO_2 mainly depended on the total amount of purge gas and the CO_2 mole fraction in the inlet syngas.The residual CO_2 concentration and uptake achieved for the inlet gas comprising CO_2(9.7 mL/min) and He(277.6 mL/min) at a working pressure of 3 MPa after 1 h of Ar purging at 300 mL/min were 12.3 ppm and0.341 mmol/g, respectively. Steam purge could greatly improve the cyclic adsorption working capacity, but had no obvious benefit for the recovery of the residual CO_2 concentration compared to purging with an inert gas. The residual CO_2 concentration obtained with the adsorbent could be reduced to 3.2 ppm after 12 h of temperature swing at 450 °C. A new concept based on an adsorption/desorption process, comprising adsorption, steam rinse, depressurization, steam purge, pressurization, and high-temperature steam purge, was proposed for reducing the steam consumption during CO/CO_2 purification.
文摘CO2 adsorption on the surface of hydrotalcite-derived mixed oxide catalysts was investigated under low pressure glow discharge plasma in opercindo conditions via FT-IR spectroscopy.Nickel catalysts were promoted with various transition metal species(Ce,Fe,La,Zr)to influence their physico-chemical properties.Fe and Zr species were successfully incorporated into hydrotalcite brucite layers.After calcination formed a single phase with Ni(Mg,A1)O mixed oxide,while La and Ce species formed separate phases.This had a consequence in the distribution of surface basic sites as well as in the affinity to CO produced upon CO2 dissociation in plasma.Plasma treatment activated the surface of prepared materials and changed their properties via the generation of strong basic sites associated with low coordinated surface oxygen anions.Moreover,the CO2 adsorption capacity of prepared materials increased after plasma treatment.
文摘In this study, Mg-Al-CO3 hydrotalcite was synthesized from a kaolinite as natural source aluminium using two simple methods. The first method uses the kaolinite in natural solid state, the second method use the filtrate of the kaolinite after dissolution by acidic solutions. The structure of the materials was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry (DSC) and Brunauer, Emmett, and Teller (BET) measurements.
文摘The use of heterogeneous catalysts in the transesterification reaction of vegetable oils has getting emphasis in recent years, mainly by the alternative of obtaining clean fuel derived from renewable sources. Metal oxide such as MgO or CaO, supported ones like ?and zeolites are often applied in transesterification process. Among them, hydrotalcite has shown potential as catalysts on this reaction due to their physicochemical properties, such as: thermal stability, porosity, specific surface area, memory effect, basicity, acidity and anion exchange capacity. This work studies the catalytic performance of the calcium and aluminum based hydrotalcite in the transesterification reaction of soybean oil in methanol and ethanol. The hydrotalcite samples treated at 450?C were impregnated with KOH. The efficiency of impregnated and non- impregnated samples was compared and the non-impregnated one showed the best performance. This property was attributed to the higher availability of active sites used in the transesterification process.
基金financial support from Directorate General of Higher Education,Republic of Indonesia through a research scheme of Penelitian Pascasarjana 2018 with contract number 1783/UN1/DITLIT/DIT-LIT/LT/2018。
文摘Water pollution with dye chemicals from apparel industries is a serious problem in the world.Since most of dyes are potentially have toxic and carcinogenic effects on human,it is important to remove them before they are discharged to the environment.Among many methods available for dyes removal in water,adsorption is the easiest and economically feasible that has no major obstacle for practical applications.In the present study,we tested calcined Mg/Al hydrotalcite(Mg/Al CHT)prepared by coprecipitation technique as an adsorbent for the removal of Navy Blue(NB)and Yellow F3G(YF3G)dyes.Mg/Al CHT was characterized by using a Fourier transform infrared(FTIR)spectrometer,an X-ray diffractometer(XRD)and a scanning electron microscope(SEM).The results showed that Mg/Al CHT was highly effective as an adsorbent for the removal of NB and YF3G under mild-acidic condition(pH 4)with removal capacities(b)according to Langmuir isotherm model were 7.97×10^(–4) and 5.80×10^(–4)mol·g^(-1),respectively.Kinetics study showed that the adsorption of NB and YF3D on Mg/Al CHT followed pseudosecond order with rate constant(k_(p2))11.57×10^(3) and 11.75×103 g·mol^(-1)·min-1,respectively.The spent adsorbent can be easily regenerated by simply calcining it at 450℃ for 3 h.Adsorption test on the mixture of NB and YF3G showed that the adsorption capacity of Mg/Al CHT was eightfold higher than that of Mg/Al HT and the value was maintained with repeated use.
基金supported by Beijing Forestry University Outstanding Young Talent Cultivation Project(2019JQ03005)the Young Tip-top Talent Project of Science and Technology Innovation by State Forestry and Grassland Administration of China(2019132609)。
文摘With the world’s fossil fuels being finite in nature,an increasing interest focuses on the application of alternative renewable resources such as biomass.Biomass-derived platform chemicals with abundant functional groups have the potential to replace bulk chemicals for the production of value-added chemicals,fuels,and materials.The upgrading of these platform chemicals relies on the development of efficient catalytic systems.Hydrotalcite,with its wide compositional variety,tuneable anion-exchange capacity,and controlled acidity/basicity sites demonstrates great potential in the catalytic upgrading of biomass and the derived platform chemicals.The past decade has witnessed the emergence of research achievements on the development of efficient and robust hydrotalcite-derived metal catalysts and their applications in the upgrading of biomass or the derived platform chemicals.In this review,we aim to summarize the recent advances on the catalytic upgrading of biomass-derived platform chemicals(e.g.,furfural,5-hydroxymethylfurfural,levulinic acid,and glycerol)via hydrotalcitederived metal catalysts.We also observed that the crucial role of using hydrotalcite-derived catalysts relies on their strong metal–support interactions.As a result,a section focusing on the discussion of the metal–support interactions of hydrotalcitederived catalysts was provided.
基金supported by the National Natural Science Foundation of China(11075113)
文摘Ni-Co bimetallic catalysts with different Ni/Co content were derived from cold plasma jet decomposition and reduction of hydrotalcite-like compounds containing Ni,Co,Mg and Al,and their catalytic performance was investigated with dry reforming of methane.Experimental results showed that the hydrotalcite-like precursors could be completely decomposed and partly reduced by cold plasma jet,and the Nicontained catalysts exhibited much higher activity than the catalyst without Ni.Especially,the catalyst with Ni/Co ratio of 8/2 achieved not only the highest conversions of 80.3%and 69.3%for CH4 and CO2,respectively,but also the best stability in 100 h testing.The catalysts were characterized by XRD,XPS,TEM and N2 adsorption techniques,and the results showed that the better performance of the 8Ni2Co bimetallic catalyst was attributed to its higher metal dispersion,smaller metal particle size,as well as the interaction effect between Ni and Co,which were brought by the special catalyst preparation method.
文摘Ammonium containing catalyst Mg/Al/Cu-NH3·H2O hydrotalcite (HT) is prepared via co-precipitation, which is effective for NOx storage under 160℃. XRD and FT-IR are employed to characterize its structure and show that ammonium is successfully incorporated into HT. Meanwhile, the HT still retains the typical structure of hydrotalcite-like compounds. NOx storage activity tests indicate Mg/Al/Cu-NH3·H2O HT shows the significant NOx removal activity at 156℃ with a little Oxygen existence. TGA and DTG reveal the reaction of the released ammonium with NOx and storage NOx as nitrates will be responsible for the high NOx storage activity. Additionally, the temperature programmed desorption test of NOx adsorbed sample under 175℃ proves NOx is stored successfully into Mg/Al/Cu-NH3·H2O HT further.
