In this article, we study modified nano-hydroxyapatite (HAp) by nano manganese oxide (Mn3O4) as adsorbent material to remove iron ions from groundwater. Different parameters were studied to option optimum conditions o...In this article, we study modified nano-hydroxyapatite (HAp) by nano manganese oxide (Mn3O4) as adsorbent material to remove iron ions from groundwater. Different parameters were studied to option optimum conditions of removing such as contact time, pH, initial concentration, a dosage of adsorbent, agitation speed and temperature. Kinetics studies included first order (R2 = 0.915), pseudo-first order (R2 = 0.936), second order (R2 = 0.948), pseudo-second order (R2 = 0.995), Elovich equation model (R2 = 0.977), intraparticle diffusion (R2 = 0.946), Natarajan and Khalaf (R2 = 0.915) were carried out, the obtained results revealed that the pseudo-second order is the best to describe the adsorption process because the correlation coefficient is approaching one (R2 = 0.995). Adsorption isotherm was calculated by using Freundlich, Langmuir and Temkin constants, adsorption capacity from Langmuir model was 0.606 mg/g. Thermodynamic parameters (ΔG, ΔH = ?51 KJ/mol, and ΔS = ?142 (KJ/mol)) for the adsorption process were also calculated and discussed.展开更多
Organic solvent free iron oxide nanomaterial used for lead removal was synthesized by co-precipitation method. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopic with energy dispersive X-ra...Organic solvent free iron oxide nanomaterial used for lead removal was synthesized by co-precipitation method. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopic with energy dispersive X-ray analysis (SEM-EDX), X-ray diffraction (XRD) and thermo gravimetric-differential thermal (TG-DTA) analysis were used to determine the surface characteristics and analysis of iron oxide. Optimization of solution pH, adsorbent dosage, contact time, agitation speed and initial lead ion concentration were conducted for further adsorption isotherm, kinetics, thermodynamics and desorption study. Langmuir sorption isotherm model fits the adsorption data better than Freundlich, Dubinin-Radushkevich (D-RK) and Flory-Huggins (FH) models. The mean adsorption energy and free energy obtained from D-RK and FH models guides that the mechanism was under control of physical adsorption and actuality of spontaneous reaction, respectively. From kinetics of adsorption pseudo second (PSO) model fits well than pseudo first (PFO) and Elovich adsorption-reaction models. And to test whether the reaction is under control of adsorption-diffusion or not the intra particle diffusion (IPD) model was tested, but it fails to pass through the origin. This indicates that the reaction mechanism only under control of adsorption-reaction. The maximum adsorption capacity (qmax) of the adsorbent was 70.422 mg/g.展开更多
Nanomaterials are increasingly used for biomedical applications; thus, it is important to understand their biological effects. Previous studies suggested that magnetic iron oxide nanoparticles （IONPs） have tissue-re...Nanomaterials are increasingly used for biomedical applications; thus, it is important to understand their biological effects. Previous studies suggested that magnetic iron oxide nanoparticles （IONPs） have tissue-repairing effects. In the present study, we explored cellular effects of IONPs in mesenchymal stem cells （MSCs） and identified the underlying molecular mechanisms. The results showed that our as-prepared IONPs were structurally stable in MSCs and promoted osteogenic differentiation of MSCs as whole particles. Moreover, at the molecular level, we compared the gene expression of MSCs with or without IONP exposure and showed that IONPs upregulated long noncoding RNA INZEB2, which is indispensable for maintaining osteogenesis by MSCs. Furthermore, overexpression of INZEB2 downregulated ZEB2, a factor necessary to repress BMP/Smad- dependent osteogenic transcription. We also demonstrated that the essential role of INZEB2 in osteogenic differentiation was ZEB2-dependent. In summary, we elucidated the molecular basis of IONPs＇ effects on MSCs; these findings may serve as a meaningful theoretical foundation for applications of stem cells to regenerative medicine.展开更多
Nanoscale zero-valent iron （nZVI） assembled on graphene oxide （GO） （rGO-nZVI） composites were synthesized by reduction of GO and ferrous ions with potassium borohydride, for use in Cr（VI） removal from aqueous ...Nanoscale zero-valent iron （nZVI） assembled on graphene oxide （GO） （rGO-nZVI） composites were synthesized by reduction of GO and ferrous ions with potassium borohydride, for use in Cr（VI） removal from aqueous solution. The results showed that the two-dimensional structure of GO could provide a skeleton support for Fe0, thus overcoming the bottleneck of aggregation for nZVI. Also, rGO-nZVI would form a ferric-carbon micro-electrolysis system in Cr（VI）-contaminated aquifers, enhancing and accelerating electron transfer, exhibiting high rate and capacity for Cr（VI） removal. The optimum dosage of the applied rGO-nZVI was linearly correlated with the initial Cr（VI） concentration. Characterization of rGO-nZVI before and after reaction with Cr（VI） revealed the process of Cr（VI） removal： rGO-nZVI firstly transferred electrons from Fe0 cores via their Fe（II）/Fe（III） shells to the GO sheet; there, negatively charged Cr（VI） received electrons and changed into positively charged Cr（III）, which was adsorbed by the negatively charged GO sheet, avoiding the capping and passivating of nZVI rGO-nZVI formed a good electrically conductive network, and thus had long-term electron releasing properties, which was important for groundwater remediation.展开更多
The technique of hydrothermal stripping from mixed aqueous-organic systems is a promising method for synthesizing oxide ceramic powders for high-performance applications. Some factors influencing heterogeneous hydroth...The technique of hydrothermal stripping from mixed aqueous-organic systems is a promising method for synthesizing oxide ceramic powders for high-performance applications. Some factors influencing heterogeneous hydrothermal stripping with water from iron-loaded organic phase of naphthenic acidisooctyl alcoholkerosene, such as initial concentrations of iron and naphthenic acid, concentration of Fe2O3 搒eed, temperature and time, were investigated. Based on the experimental results, the rate equation was established. Nano-ferric oxide powders were obtained by the technique of hydrothermal stripping from the iron-loaded organic phase. The results suggest that the heterogeneous hydrothermal stripping proceeds in 3 steps: adsorption of naphthenic acid dimers and naphthenic complex of iron onto the surface of seed? hydrolysis of adsorbed complex of iron, and condensation of hydrolyzed complex. The process activation energy is 115 kJ/mol and the heterogeneous hydrothermal stripping is controlled by a chemical reaction (the hydrolysis of naphthenic complex of iron).展开更多
文摘In this article, we study modified nano-hydroxyapatite (HAp) by nano manganese oxide (Mn3O4) as adsorbent material to remove iron ions from groundwater. Different parameters were studied to option optimum conditions of removing such as contact time, pH, initial concentration, a dosage of adsorbent, agitation speed and temperature. Kinetics studies included first order (R2 = 0.915), pseudo-first order (R2 = 0.936), second order (R2 = 0.948), pseudo-second order (R2 = 0.995), Elovich equation model (R2 = 0.977), intraparticle diffusion (R2 = 0.946), Natarajan and Khalaf (R2 = 0.915) were carried out, the obtained results revealed that the pseudo-second order is the best to describe the adsorption process because the correlation coefficient is approaching one (R2 = 0.995). Adsorption isotherm was calculated by using Freundlich, Langmuir and Temkin constants, adsorption capacity from Langmuir model was 0.606 mg/g. Thermodynamic parameters (ΔG, ΔH = ?51 KJ/mol, and ΔS = ?142 (KJ/mol)) for the adsorption process were also calculated and discussed.
文摘Organic solvent free iron oxide nanomaterial used for lead removal was synthesized by co-precipitation method. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopic with energy dispersive X-ray analysis (SEM-EDX), X-ray diffraction (XRD) and thermo gravimetric-differential thermal (TG-DTA) analysis were used to determine the surface characteristics and analysis of iron oxide. Optimization of solution pH, adsorbent dosage, contact time, agitation speed and initial lead ion concentration were conducted for further adsorption isotherm, kinetics, thermodynamics and desorption study. Langmuir sorption isotherm model fits the adsorption data better than Freundlich, Dubinin-Radushkevich (D-RK) and Flory-Huggins (FH) models. The mean adsorption energy and free energy obtained from D-RK and FH models guides that the mechanism was under control of physical adsorption and actuality of spontaneous reaction, respectively. From kinetics of adsorption pseudo second (PSO) model fits well than pseudo first (PFO) and Elovich adsorption-reaction models. And to test whether the reaction is under control of adsorption-diffusion or not the intra particle diffusion (IPD) model was tested, but it fails to pass through the origin. This indicates that the reaction mechanism only under control of adsorption-reaction. The maximum adsorption capacity (qmax) of the adsorbent was 70.422 mg/g.
文摘Nanomaterials are increasingly used for biomedical applications; thus, it is important to understand their biological effects. Previous studies suggested that magnetic iron oxide nanoparticles （IONPs） have tissue-repairing effects. In the present study, we explored cellular effects of IONPs in mesenchymal stem cells （MSCs） and identified the underlying molecular mechanisms. The results showed that our as-prepared IONPs were structurally stable in MSCs and promoted osteogenic differentiation of MSCs as whole particles. Moreover, at the molecular level, we compared the gene expression of MSCs with or without IONP exposure and showed that IONPs upregulated long noncoding RNA INZEB2, which is indispensable for maintaining osteogenesis by MSCs. Furthermore, overexpression of INZEB2 downregulated ZEB2, a factor necessary to repress BMP/Smad- dependent osteogenic transcription. We also demonstrated that the essential role of INZEB2 in osteogenic differentiation was ZEB2-dependent. In summary, we elucidated the molecular basis of IONPs＇ effects on MSCs; these findings may serve as a meaningful theoretical foundation for applications of stem cells to regenerative medicine.
基金supported by the National Natural Science Foundation of China(Nos.41772244 and 41530636)
文摘Nanoscale zero-valent iron （nZVI） assembled on graphene oxide （GO） （rGO-nZVI） composites were synthesized by reduction of GO and ferrous ions with potassium borohydride, for use in Cr（VI） removal from aqueous solution. The results showed that the two-dimensional structure of GO could provide a skeleton support for Fe0, thus overcoming the bottleneck of aggregation for nZVI. Also, rGO-nZVI would form a ferric-carbon micro-electrolysis system in Cr（VI）-contaminated aquifers, enhancing and accelerating electron transfer, exhibiting high rate and capacity for Cr（VI） removal. The optimum dosage of the applied rGO-nZVI was linearly correlated with the initial Cr（VI） concentration. Characterization of rGO-nZVI before and after reaction with Cr（VI） revealed the process of Cr（VI） removal： rGO-nZVI firstly transferred electrons from Fe0 cores via their Fe（II）/Fe（III） shells to the GO sheet; there, negatively charged Cr（VI） received electrons and changed into positively charged Cr（III）, which was adsorbed by the negatively charged GO sheet, avoiding the capping and passivating of nZVI rGO-nZVI formed a good electrically conductive network, and thus had long-term electron releasing properties, which was important for groundwater remediation.
基金Supported by the National Natural Science Foundation of China (No.: 59934080)
文摘The technique of hydrothermal stripping from mixed aqueous-organic systems is a promising method for synthesizing oxide ceramic powders for high-performance applications. Some factors influencing heterogeneous hydrothermal stripping with water from iron-loaded organic phase of naphthenic acidisooctyl alcoholkerosene, such as initial concentrations of iron and naphthenic acid, concentration of Fe2O3 搒eed, temperature and time, were investigated. Based on the experimental results, the rate equation was established. Nano-ferric oxide powders were obtained by the technique of hydrothermal stripping from the iron-loaded organic phase. The results suggest that the heterogeneous hydrothermal stripping proceeds in 3 steps: adsorption of naphthenic acid dimers and naphthenic complex of iron onto the surface of seed? hydrolysis of adsorbed complex of iron, and condensation of hydrolyzed complex. The process activation energy is 115 kJ/mol and the heterogeneous hydrothermal stripping is controlled by a chemical reaction (the hydrolysis of naphthenic complex of iron).
