It is of great importance to elucidate reduction swelling behaviors and reaction mechanism of oxidized pellet in hydrogen-enriched atmosphere under coke oven gas injection. In this work, the effects of hydrogen concen...It is of great importance to elucidate reduction swelling behaviors and reaction mechanism of oxidized pellet in hydrogen-enriched atmosphere under coke oven gas injection. In this work, the effects of hydrogen concentration in N_2-CO-H_2 atmosphere with unchanged CO content on reduction swelling behaviors of oxidized pellet at 1173 K were studied, to clarify the mechanism of hydrogen-enriched reduction and exclude the influences of CO. Then, the reduction swelling behaviors of oxidized pellet at 1173 K in actual atmosphere under coke oven gas(COG) injection, got from the simulation results of multi-fluid blast furnace model, were investigated. The results show that with the concentration of hydrogen increasing in N_2-CO-H_2 gas from 2% to 18%, the reduction swelling index of pellet decreases from 10.12% to 5.57% while the reduction ratio of pellet increases obviously from 39.85% to 69.58%. In addition, with COG injection rate increasing from 0 to 152.34 m^3/t, the reduction swelling index of pellet decreases slightly from 10.71% to 9.54% while the reduction ratio of pellet is increased from 31.57% to 36.39%. The microstructures of pellet are transformed from the platy structure to the flocculent structure.展开更多
In this work, we studied the swelling and deswelling kinetics of polyvinyl alcohol (PVA) and lactic acid (LA) hydrogel films between distilled water and acetone phase. The hydrogel films were prepared by dissolve 5.0 ...In this work, we studied the swelling and deswelling kinetics of polyvinyl alcohol (PVA) and lactic acid (LA) hydrogel films between distilled water and acetone phase. The hydrogel films were prepared by dissolve 5.0 g of PVA in hot water. Then, 7.5 g LA solution was slowly added into the clearly PVA solution at room temperature. After that, the mixture solution was subsequently cured in an oven for different curing times at 100°C.展开更多
In the oil industry, techniques decreasing unwanted water production have drawn large amounts of interest from many companies. During water injection operations, water is injected into the oil reservoir to extract oil...In the oil industry, techniques decreasing unwanted water production have drawn large amounts of interest from many companies. During water injection operations, water is injected into the oil reservoir to extract oil trapped in the formation. Due to the heterogeneity in the reservoir formation, oil production will decline and water production will increase as the injected water sweeps the high permeability zones. In order to flush out the oil remaining in the low permeability zones, many treatments have been used. One such treatment involves the injection of an SAP （superabsorbent polymer） into the high permeability zones. The swelled polymer will decrease the heterogeneity of reservoir permeability, thus forcing water injection into the oil rich, unswept zones/areas of the formation. Proper application of an SAP can have a dramatic impact on both the production and lifespan of mature oil wells. Successful treatment is reliant upon the reservoir salinity, temperature, and pH.展开更多
Polyvinyl alcohol(PVA) physiological saline gel was prepared using physiological saline solution of the polymer by freezing and thawing method. The influences of the concentration of PVA, freezing and thawing cycle ti...Polyvinyl alcohol(PVA) physiological saline gel was prepared using physiological saline solution of the polymer by freezing and thawing method. The influences of the concentration of PVA, freezing and thawing cycle times and solvent swelling media on the swelling properties of PVA saline gel were investigated. The result show that the electrolytical ions have great effect on the swelling behavior of PVA saline gel. The equilibrium swelling ratio of PVA saline gel in aqueous swelling media is larger than that in saline swelling media. Also, the equilibrium swelling ratios of PVA saline gel in aqueous and in saline media decrease with the increase of gel concentration and the increase of freezing and thawing cycle times. The decreasing speed of equilibrium swelling ratio with the increase of freezing and thawing cycle times of PVA gel in distilled water is faster than that in physiological saline. The swelling kinetic equation can sufficiently describe the swelling behavior of PVA physiological saline gel.展开更多
Macroporous acrylonitrile-acrylic acid （AN-AA） copolymer hydrogels were synthesized by flee-radical solution polymerizations, using ammonium persulfate （APS）/N,N,N＇,N＇-tetramethylethylenediamine （TEMED） redox ...Macroporous acrylonitrile-acrylic acid （AN-AA） copolymer hydrogels were synthesized by flee-radical solution polymerizations, using ammonium persulfate （APS）/N,N,N＇,N＇-tetramethylethylenediamine （TEMED） redox initiator system and alcohols porogens. The morphology, temperature and pH sensitive swelling behavior, and swelling kinetics of the resulting hydrogels were investigated. It was found that alcohol type and concentration had great influences on the pore structure and porosity of hydrogels. The pore size of hydrogel increases with the moderate increase of the length of alcohol alkyl chain. However, a further increase of alkyl length would result in the formation of cauliflower-like structure and the decrease of pore size. The porosity of hydrogels increases with the increase of porogen concentration in the polymerization medium. The hydrogels with macroporous structure swell or shrink much faster in response to the change of pH in comparison with the conventional hydrogel without macroporous structure. Furthermore, the response rate is closely related to the porosity of the hydrogels, which could be easily controlled by modulating the concentration of the porogen in the medium. The circular swelling behavior of hydrogels indicated the formation of a relaxing three-dimensional network.展开更多
A series of cross-linked hydrogels for colon-specific drug delivery were synthesized by graft copolymerization of Chitosan and acrylic acid using N, N＇-methylene-bis-（acrylamide） as a cross-linker. Their swelling b...A series of cross-linked hydrogels for colon-specific drug delivery were synthesized by graft copolymerization of Chitosan and acrylic acid using N, N＇-methylene-bis-（acrylamide） as a cross-linker. Their swelling behavior in different pH buffer solutions and colonic enzymatic degradability were studied. The obtained results show that these hydrogels have good pH sensitivity which can avoid drug release in stomach, and their swelling kinetics in stimulant intestinal environment follow second-order swelling kinetics equation. The factors influencing the swelling kinetics include the degree of cross-linking and the composition, which may control no release or a little amount release of drug inside the hydrogels in the small intestine by tailoring these factors. The gels are degradable by colonic enzymes and there is a correlativity between the degradation of networks and the swelling degree of the gels, which may trigger the release of drug in the colon. The hydrogels show a great potential for their application in oral colon-specific drug delivery system.展开更多
Hydrogels based on acrylamide (AA) and sodium methacrylate (NMA) as ionic monomer were prepared by solution polymerization using N,N’-methylenebis(acrylamide) (MBA) or ethylene glycol dimethacrylate (EGMA) as crossli...Hydrogels based on acrylamide (AA) and sodium methacrylate (NMA) as ionic monomer were prepared by solution polymerization using N,N’-methylenebis(acrylamide) (MBA) or ethylene glycol dimethacrylate (EGMA) as crosslinkers and Ammonium Persulfate (APS) and N,N,N’,N’-Te-tramethyl-ethylenediamine (TMEDA) as initiators. Swelling behavior was greatly affected by NMA content near phase transition. Increasing ionic monomer concentration compared to total monomer one led to high expansion in water, oscillating around 285 g/g for MBA and 325 g/g for EGMA crosslinker, above 20% of NMA. Dynamic Light Scattering experiments were performed and, for both crosslinkers, the dynamic correlation length (ξ) decreased with increasing NMA content, contributing to diminish hydrogels spatial inhomogeneities.展开更多
Fine unsaturated soils are used in many applications, particularly in road infrastructure and in construction. These materials undergo deformations according to the stresses to which they are subjected. The purpose of...Fine unsaturated soils are used in many applications, particularly in road infrastructure and in construction. These materials undergo deformations according to the stresses to which they are subjected. The purpose of this paper is to study the influence of hydromechanical stresses on the behavior of low swelling soils compacted at low water content in accordance with the French standard GTR 92 (Guide des Terrassements Routiers). Then, various experimental tests on an oedometer were carried out in the laboratory. Two types of low swelling soil sampled in Nasso on the outskirts of the town of Bobo Dioulasso (Burkina Faso) were used. After shuffling, each sample was moistened to its optimum water content and then compacted to 90% and 95% of its optimum density. Behavior tests show that these soils deform very little when subjected to hydromechanical stresses. However, these deformations are swelling in nature for low mechanical stresses and when the stresses are high, they tend to collapse. When these soils are subjected to a vertical stress of 420 kPa, the primary consolidation time is of the order of one minute for NH<sub>2</sub> (a silty soil) and about ten minutes for NH<sub>3 </sub>(a silty-clayed soil).展开更多
Coal permeability measurements are normally conducted under the assumption that gas pressure in the matrix is equalized with that in fracture and that gas sorption-induced swelling/shrinking strain is uniformly distri...Coal permeability measurements are normally conducted under the assumption that gas pressure in the matrix is equalized with that in fracture and that gas sorption-induced swelling/shrinking strain is uniformly distributed within the coal.However,the validity of this assumption has long been questioned and differential strain between the fracture strain and the bulk strain has long been considered as the primary reason for the inconsistency between experimental data and poroelasticity solutions.Although efforts have been made to incorporate the impact into coal permeability models,the fundamental nature of those efforts to split the matrix strain between fracture and coal bulk remains questionable.In this study,a new concept of differential swelling index(DSI)was derived to theoretically define the relation among sorption-induced strains of the coal bulk,fracture,and coal matrix at the equilibrium state.DSI was a function of the equilibrium pressure and its magnitudes were regulated by the Langmuir constants of both the matrix and the coal bulk.Furthermore,a spectrum of DSI-based coal permeability models was developed to explicitly consider the effect of differential strains.These models were verified with the experimental data under the conditions of uniaxial strain,constant confining pressure,and constant effective stress.展开更多
Three kinds of amphiphilic PMADAB gels were prepared through radiation-induced polymerization and crosslinking of methacryloxyethyl dimethylalkane ammonium bromide(MADAB) with different alkyl side chains(butyl,octyl a...Three kinds of amphiphilic PMADAB gels were prepared through radiation-induced polymerization and crosslinking of methacryloxyethyl dimethylalkane ammonium bromide(MADAB) with different alkyl side chains(butyl,octyl and dodecyl).The length of alkyl side chains had significant influence on swelling behavior of the PMADAB gels in alcohol/water solvent.Equilibrium swelling degree(EDS) of PMBDAB(butyl) gel in water was ca.160 and decreased with increasing alcohol content(x),whereas EDS of PMODAB(octyl)and PMDDDAB(dodecyl) gels showed a convex-upward function of x,i.e.,these two gels barely swelled in pure water and swelled with increasing x and then shrank gradually.This phenomenon was explained by the hydrophobic association of long alkyl chains and a cosolvency effect of PMADAB in alcohol and water.The swelling behavior of PMADAB gels in methanol,ethanol and isopropanol were similar,and their EDS are related with the dielectric constant of alcohol solvents.The results suggest that PMADAB gels may be potential absorbents for various kinds of alcohols.展开更多
The mass transfer between heavy oil and liquid carbon dioxide and the changes of the heavy phase(mixture of heavy oil and CO_2) and light phase(pure CO_2) in the mixture were tested in lab with heavy oil samples from ...The mass transfer between heavy oil and liquid carbon dioxide and the changes of the heavy phase(mixture of heavy oil and CO_2) and light phase(pure CO_2) in the mixture were tested in lab with heavy oil samples from Russia. The experimental results showed that the heavy oil hardly expanded when the concentration of carbon dioxide in the mixture was 10%. When the concentration of carbon dioxide was higher than 26%, the volume of the heavy phase decreased, and the viscosity of the heavy phase increased exponentially as the light components extracted from the heavy oil exceeded the carbon dioxide saturated in the heavy oil. When the concentration of carbon dioxide in the mixture was 26%, the effect of viscosity reducing to the heavy phase was the strongest. The density of the light and heavy phases, volume factor, and solubility of gas and flash viscosity of heavy phase all increased with the rise of carbon dioxide concentration in the mixture. The best concentration of carbon dioxide in the mixture was 26%, when the heavy oil expanded the most and the viscosity of the heavy phase was the lowest. When the concentration of carbon dioxide in the mixture was between 10% and 26%, the volume of the light phase was the smallest and the oil displacement effect was the best.展开更多
A graft copolymer of polyacrylonitrile （PAN） with sodium salt of partially carboxymethylated tamarind kernel powder （Na-PCMTKP, DS ^-= 0.15） was synthesized by using ceric ammonium nitrate （CAN） as a redox initi...A graft copolymer of polyacrylonitrile （PAN） with sodium salt of partially carboxymethylated tamarind kernel powder （Na-PCMTKP, DS ^-= 0.15） was synthesized by using ceric ammonium nitrate （CAN） as a redox initiator in an aqueous medium. The optimum reaction conditions for affording maximum percentage of grafting were established by successively varying reaction conditions such as concentrations of nitric acid, CAN, monomer （AN） as well as reaction time, temperature and amount of substrate. The influence of these reaction conditions on the grafting yields was discussed. The kinetic scheme of free radical graft copolymerization was proposed and the experimental results were found to agree very well with the proposed kinetic scheme. The graft copolymer （Na-PCMTKP-g-PAN, percentage of grafting G = 413.76% and percentage of grafting efficiency GE = 96.48%） sample synthesized under the established optimized reaction conditions was hydrolyzed by 0.7 mol-L l NaOH solution at 90-95 ℃ to yield the superabsorbent hydrogel, H-Na-PCMTKP-g-PAN. The swelling behavior of the hydrogel was studied by carrying out its absorbency measurements in low conductivity water, 0.15 mol·L^-1 salt （NaCl, CaCl2 and AlCl3） solutions and simulated urine （SU） solution at different timings. FTIR, TGA and SEM techniques were used to characterize the products.展开更多
基金Project(51404005)supported by the National Natural Science Foundation of China
文摘It is of great importance to elucidate reduction swelling behaviors and reaction mechanism of oxidized pellet in hydrogen-enriched atmosphere under coke oven gas injection. In this work, the effects of hydrogen concentration in N_2-CO-H_2 atmosphere with unchanged CO content on reduction swelling behaviors of oxidized pellet at 1173 K were studied, to clarify the mechanism of hydrogen-enriched reduction and exclude the influences of CO. Then, the reduction swelling behaviors of oxidized pellet at 1173 K in actual atmosphere under coke oven gas(COG) injection, got from the simulation results of multi-fluid blast furnace model, were investigated. The results show that with the concentration of hydrogen increasing in N_2-CO-H_2 gas from 2% to 18%, the reduction swelling index of pellet decreases from 10.12% to 5.57% while the reduction ratio of pellet increases obviously from 39.85% to 69.58%. In addition, with COG injection rate increasing from 0 to 152.34 m^3/t, the reduction swelling index of pellet decreases slightly from 10.71% to 9.54% while the reduction ratio of pellet is increased from 31.57% to 36.39%. The microstructures of pellet are transformed from the platy structure to the flocculent structure.
文摘In this work, we studied the swelling and deswelling kinetics of polyvinyl alcohol (PVA) and lactic acid (LA) hydrogel films between distilled water and acetone phase. The hydrogel films were prepared by dissolve 5.0 g of PVA in hot water. Then, 7.5 g LA solution was slowly added into the clearly PVA solution at room temperature. After that, the mixture solution was subsequently cured in an oven for different curing times at 100°C.
文摘In the oil industry, techniques decreasing unwanted water production have drawn large amounts of interest from many companies. During water injection operations, water is injected into the oil reservoir to extract oil trapped in the formation. Due to the heterogeneity in the reservoir formation, oil production will decline and water production will increase as the injected water sweeps the high permeability zones. In order to flush out the oil remaining in the low permeability zones, many treatments have been used. One such treatment involves the injection of an SAP （superabsorbent polymer） into the high permeability zones. The swelled polymer will decrease the heterogeneity of reservoir permeability, thus forcing water injection into the oil rich, unswept zones/areas of the formation. Proper application of an SAP can have a dramatic impact on both the production and lifespan of mature oil wells. Successful treatment is reliant upon the reservoir salinity, temperature, and pH.
文摘Polyvinyl alcohol(PVA) physiological saline gel was prepared using physiological saline solution of the polymer by freezing and thawing method. The influences of the concentration of PVA, freezing and thawing cycle times and solvent swelling media on the swelling properties of PVA saline gel were investigated. The result show that the electrolytical ions have great effect on the swelling behavior of PVA saline gel. The equilibrium swelling ratio of PVA saline gel in aqueous swelling media is larger than that in saline swelling media. Also, the equilibrium swelling ratios of PVA saline gel in aqueous and in saline media decrease with the increase of gel concentration and the increase of freezing and thawing cycle times. The decreasing speed of equilibrium swelling ratio with the increase of freezing and thawing cycle times of PVA gel in distilled water is faster than that in physiological saline. The swelling kinetic equation can sufficiently describe the swelling behavior of PVA physiological saline gel.
文摘Macroporous acrylonitrile-acrylic acid （AN-AA） copolymer hydrogels were synthesized by flee-radical solution polymerizations, using ammonium persulfate （APS）/N,N,N＇,N＇-tetramethylethylenediamine （TEMED） redox initiator system and alcohols porogens. The morphology, temperature and pH sensitive swelling behavior, and swelling kinetics of the resulting hydrogels were investigated. It was found that alcohol type and concentration had great influences on the pore structure and porosity of hydrogels. The pore size of hydrogel increases with the moderate increase of the length of alcohol alkyl chain. However, a further increase of alkyl length would result in the formation of cauliflower-like structure and the decrease of pore size. The porosity of hydrogels increases with the increase of porogen concentration in the polymerization medium. The hydrogels with macroporous structure swell or shrink much faster in response to the change of pH in comparison with the conventional hydrogel without macroporous structure. Furthermore, the response rate is closely related to the porosity of the hydrogels, which could be easily controlled by modulating the concentration of the porogen in the medium. The circular swelling behavior of hydrogels indicated the formation of a relaxing three-dimensional network.
基金Funded by the National Natural Science Foundation of China (No.50503019)
文摘A series of cross-linked hydrogels for colon-specific drug delivery were synthesized by graft copolymerization of Chitosan and acrylic acid using N, N＇-methylene-bis-（acrylamide） as a cross-linker. Their swelling behavior in different pH buffer solutions and colonic enzymatic degradability were studied. The obtained results show that these hydrogels have good pH sensitivity which can avoid drug release in stomach, and their swelling kinetics in stimulant intestinal environment follow second-order swelling kinetics equation. The factors influencing the swelling kinetics include the degree of cross-linking and the composition, which may control no release or a little amount release of drug inside the hydrogels in the small intestine by tailoring these factors. The gels are degradable by colonic enzymes and there is a correlativity between the degradation of networks and the swelling degree of the gels, which may trigger the release of drug in the colon. The hydrogels show a great potential for their application in oral colon-specific drug delivery system.
文摘Hydrogels based on acrylamide (AA) and sodium methacrylate (NMA) as ionic monomer were prepared by solution polymerization using N,N’-methylenebis(acrylamide) (MBA) or ethylene glycol dimethacrylate (EGMA) as crosslinkers and Ammonium Persulfate (APS) and N,N,N’,N’-Te-tramethyl-ethylenediamine (TMEDA) as initiators. Swelling behavior was greatly affected by NMA content near phase transition. Increasing ionic monomer concentration compared to total monomer one led to high expansion in water, oscillating around 285 g/g for MBA and 325 g/g for EGMA crosslinker, above 20% of NMA. Dynamic Light Scattering experiments were performed and, for both crosslinkers, the dynamic correlation length (ξ) decreased with increasing NMA content, contributing to diminish hydrogels spatial inhomogeneities.
文摘Fine unsaturated soils are used in many applications, particularly in road infrastructure and in construction. These materials undergo deformations according to the stresses to which they are subjected. The purpose of this paper is to study the influence of hydromechanical stresses on the behavior of low swelling soils compacted at low water content in accordance with the French standard GTR 92 (Guide des Terrassements Routiers). Then, various experimental tests on an oedometer were carried out in the laboratory. Two types of low swelling soil sampled in Nasso on the outskirts of the town of Bobo Dioulasso (Burkina Faso) were used. After shuffling, each sample was moistened to its optimum water content and then compacted to 90% and 95% of its optimum density. Behavior tests show that these soils deform very little when subjected to hydromechanical stresses. However, these deformations are swelling in nature for low mechanical stresses and when the stresses are high, they tend to collapse. When these soils are subjected to a vertical stress of 420 kPa, the primary consolidation time is of the order of one minute for NH<sub>2</sub> (a silty soil) and about ten minutes for NH<sub>3 </sub>(a silty-clayed soil).
基金supported by National Key R&D Program of China(Grant No.2018YFC0407006)the 111 Project(Grant No.B17009)the Australian Research Council(Grant No.DP200101293)。
文摘Coal permeability measurements are normally conducted under the assumption that gas pressure in the matrix is equalized with that in fracture and that gas sorption-induced swelling/shrinking strain is uniformly distributed within the coal.However,the validity of this assumption has long been questioned and differential strain between the fracture strain and the bulk strain has long been considered as the primary reason for the inconsistency between experimental data and poroelasticity solutions.Although efforts have been made to incorporate the impact into coal permeability models,the fundamental nature of those efforts to split the matrix strain between fracture and coal bulk remains questionable.In this study,a new concept of differential swelling index(DSI)was derived to theoretically define the relation among sorption-induced strains of the coal bulk,fracture,and coal matrix at the equilibrium state.DSI was a function of the equilibrium pressure and its magnitudes were regulated by the Langmuir constants of both the matrix and the coal bulk.Furthermore,a spectrum of DSI-based coal permeability models was developed to explicitly consider the effect of differential strains.These models were verified with the experimental data under the conditions of uniaxial strain,constant confining pressure,and constant effective stress.
基金Supported by the China Postdoctoral Science Foundation(No.2012M520164)the Fundamental Research Funds for the Central Universities(No.FRF-TP-13-008A)
文摘Three kinds of amphiphilic PMADAB gels were prepared through radiation-induced polymerization and crosslinking of methacryloxyethyl dimethylalkane ammonium bromide(MADAB) with different alkyl side chains(butyl,octyl and dodecyl).The length of alkyl side chains had significant influence on swelling behavior of the PMADAB gels in alcohol/water solvent.Equilibrium swelling degree(EDS) of PMBDAB(butyl) gel in water was ca.160 and decreased with increasing alcohol content(x),whereas EDS of PMODAB(octyl)and PMDDDAB(dodecyl) gels showed a convex-upward function of x,i.e.,these two gels barely swelled in pure water and swelled with increasing x and then shrank gradually.This phenomenon was explained by the hydrophobic association of long alkyl chains and a cosolvency effect of PMADAB in alcohol and water.The swelling behavior of PMADAB gels in methanol,ethanol and isopropanol were similar,and their EDS are related with the dielectric constant of alcohol solvents.The results suggest that PMADAB gels may be potential absorbents for various kinds of alcohols.
文摘The mass transfer between heavy oil and liquid carbon dioxide and the changes of the heavy phase(mixture of heavy oil and CO_2) and light phase(pure CO_2) in the mixture were tested in lab with heavy oil samples from Russia. The experimental results showed that the heavy oil hardly expanded when the concentration of carbon dioxide in the mixture was 10%. When the concentration of carbon dioxide was higher than 26%, the volume of the heavy phase decreased, and the viscosity of the heavy phase increased exponentially as the light components extracted from the heavy oil exceeded the carbon dioxide saturated in the heavy oil. When the concentration of carbon dioxide in the mixture was 26%, the effect of viscosity reducing to the heavy phase was the strongest. The density of the light and heavy phases, volume factor, and solubility of gas and flash viscosity of heavy phase all increased with the rise of carbon dioxide concentration in the mixture. The best concentration of carbon dioxide in the mixture was 26%, when the heavy oil expanded the most and the viscosity of the heavy phase was the lowest. When the concentration of carbon dioxide in the mixture was between 10% and 26%, the volume of the light phase was the smallest and the oil displacement effect was the best.
文摘A graft copolymer of polyacrylonitrile （PAN） with sodium salt of partially carboxymethylated tamarind kernel powder （Na-PCMTKP, DS ^-= 0.15） was synthesized by using ceric ammonium nitrate （CAN） as a redox initiator in an aqueous medium. The optimum reaction conditions for affording maximum percentage of grafting were established by successively varying reaction conditions such as concentrations of nitric acid, CAN, monomer （AN） as well as reaction time, temperature and amount of substrate. The influence of these reaction conditions on the grafting yields was discussed. The kinetic scheme of free radical graft copolymerization was proposed and the experimental results were found to agree very well with the proposed kinetic scheme. The graft copolymer （Na-PCMTKP-g-PAN, percentage of grafting G = 413.76% and percentage of grafting efficiency GE = 96.48%） sample synthesized under the established optimized reaction conditions was hydrolyzed by 0.7 mol-L l NaOH solution at 90-95 ℃ to yield the superabsorbent hydrogel, H-Na-PCMTKP-g-PAN. The swelling behavior of the hydrogel was studied by carrying out its absorbency measurements in low conductivity water, 0.15 mol·L^-1 salt （NaCl, CaCl2 and AlCl3） solutions and simulated urine （SU） solution at different timings. FTIR, TGA and SEM techniques were used to characterize the products.
