Login In
2019 Volume 36 Issue 12
2019, 36(12): 1343-1360
doi: 10.11944/j.issn.1000-0518.2019.12.190170
Abstract:
The chiral 3-amino-2-oxindole skeletons are widely present in many drug molecules and natural products, and show high medicinal value. The asymmetric reaction involving of isatin-derived ketimines provides a direct access to chiral 3-amino-2-oxindole derivatives. In this paper, the recent progress on the asymmetric aza-Henry, cyclization and other asymmetric reactions for the construction of 3-amino-2-oxindoles skeleton with isatin-derived ketimines is reviewed and the future development is prospected.
The chiral 3-amino-2-oxindole skeletons are widely present in many drug molecules and natural products, and show high medicinal value. The asymmetric reaction involving of isatin-derived ketimines provides a direct access to chiral 3-amino-2-oxindole derivatives. In this paper, the recent progress on the asymmetric aza-Henry, cyclization and other asymmetric reactions for the construction of 3-amino-2-oxindoles skeleton with isatin-derived ketimines is reviewed and the future development is prospected.
2019, 36(12): 1361-1370
doi: 10.11944/j.issn.1000-0518.2019.12.190107
Abstract:
Recent progress of cellulose-based superwettable materials for oil/water separation is reviewed in this paper. Firstly, three types of cellulose-based oil/water separation materials are summarized according to their different wettability. The intelligent responsive materials are highlighted along with our research work. Besides, the research of cellulose-based superwettable materials for other fields are also introduced. We envision further directions of cellulose-based materials and put forward some urgent questions that should be solved.
Recent progress of cellulose-based superwettable materials for oil/water separation is reviewed in this paper. Firstly, three types of cellulose-based oil/water separation materials are summarized according to their different wettability. The intelligent responsive materials are highlighted along with our research work. Besides, the research of cellulose-based superwettable materials for other fields are also introduced. We envision further directions of cellulose-based materials and put forward some urgent questions that should be solved.
2019, 36(12): 1371-1375
doi: 10.11944/j.issn.1000-0518.2019.12.190147
Abstract:
In this paper, the chloroform solution of[2.2]paracyclophane is irradiated under 254 nm ultraviolet light to yield two main products, i.e. 4-formyl[2.2]paracyclophane and 4, 4'-(ethane-1, 2-diyl)dibenzaldehyde. The structures of the products are characterized by nuclear magnetic resonance spectroscopy (NMR), gas chromatography-mass spectrometer (GC-MS). The reaction conditions are explored. The coexistence of chloroform and water is important to form the aldehyde products and a possible reaction mechanism that the CHCl2· radical is added to the benzene ring and further forms an aldehyde group by Reimer-Tiemann reaction is proposed.
In this paper, the chloroform solution of[2.2]paracyclophane is irradiated under 254 nm ultraviolet light to yield two main products, i.e. 4-formyl[2.2]paracyclophane and 4, 4'-(ethane-1, 2-diyl)dibenzaldehyde. The structures of the products are characterized by nuclear magnetic resonance spectroscopy (NMR), gas chromatography-mass spectrometer (GC-MS). The reaction conditions are explored. The coexistence of chloroform and water is important to form the aldehyde products and a possible reaction mechanism that the CHCl2· radical is added to the benzene ring and further forms an aldehyde group by Reimer-Tiemann reaction is proposed.
2019, 36(12): 1376-1386
doi: 10.11944/j.issn.1000-0518.2019.12.190066
Abstract:
10-(4-Phenothiazine)-5, 15-bis(pentafluorophenyl)corrolatoiron (2-Fe) was synthesized. Complex 2-Fe displays high cytotoxic activity against human lung adenocarcinoma (A549) cell lines. Flow cytometry detected 2-Fe arrested the cell cycle in the S and G2 phase in the presence of H2O2 and apoptotic rate was 63.76%. Hoechst-33342 staining showed considerable morphological changes in nuclear chromatin and mitochondrial transmembrane potential dropped respectively. Complex 2-Fe could interact with DNA via an outside binding mode and trigger 1O2 generation.
10-(4-Phenothiazine)-5, 15-bis(pentafluorophenyl)corrolatoiron (2-Fe) was synthesized. Complex 2-Fe displays high cytotoxic activity against human lung adenocarcinoma (A549) cell lines. Flow cytometry detected 2-Fe arrested the cell cycle in the S and G2 phase in the presence of H2O2 and apoptotic rate was 63.76%. Hoechst-33342 staining showed considerable morphological changes in nuclear chromatin and mitochondrial transmembrane potential dropped respectively. Complex 2-Fe could interact with DNA via an outside binding mode and trigger 1O2 generation.
2019, 36(12): 1387-1396
doi: 10.11944/j.issn.1000-0518.2019.12.190100
Abstract:
Two di-2, 4-dichlorobenzyltin complexes (C1, C2) have been synthesized from p-methoxybenzoyl hydrazide-2-ketobutyric acid or 2-thiophene hydrazide2-ketobutyric acid with di-2, 4-dichlorobenzyltin dichloride, respectively. The properties and the crystal structures of the complexes C1 and C2 were characterized by Fourier transform infrared spectrometer (FTIR), nuclear magnetic resonance spectroscopy (NMR) and single crystal X-ray diffraction (SCXRD). Two complexes are all binuclear molecules containing a Sn2O2 four-membered ring. The central tin atom and the coordination atom form a hepta-coordinationed distorted pentagonal bipyramid configuration. The complexes C1 and C2 are stable under 120℃ in air, and exihibit good inhibitory effects on human non-small cell lung cancer (NCI-H460), human liver hepatocellular carcinoma (HepG2) and human breast adenocarcinoma (MCF-7) cancer cells cancer cells, but complex C1 is slightly better than complex C2. The interaction between two complexes and calf thymus DNA is intercalation, and the effect of complex C1 and DNA is slightly stronger than that of complex C2.
Two di-2, 4-dichlorobenzyltin complexes (C1, C2) have been synthesized from p-methoxybenzoyl hydrazide-2-ketobutyric acid or 2-thiophene hydrazide2-ketobutyric acid with di-2, 4-dichlorobenzyltin dichloride, respectively. The properties and the crystal structures of the complexes C1 and C2 were characterized by Fourier transform infrared spectrometer (FTIR), nuclear magnetic resonance spectroscopy (NMR) and single crystal X-ray diffraction (SCXRD). Two complexes are all binuclear molecules containing a Sn2O2 four-membered ring. The central tin atom and the coordination atom form a hepta-coordinationed distorted pentagonal bipyramid configuration. The complexes C1 and C2 are stable under 120℃ in air, and exihibit good inhibitory effects on human non-small cell lung cancer (NCI-H460), human liver hepatocellular carcinoma (HepG2) and human breast adenocarcinoma (MCF-7) cancer cells cancer cells, but complex C1 is slightly better than complex C2. The interaction between two complexes and calf thymus DNA is intercalation, and the effect of complex C1 and DNA is slightly stronger than that of complex C2.
2019, 36(12): 1397-1405
doi: 10.11944/j.issn.1000-0518.2019.12.190125
Abstract:
Based on N, N'-bis-(3-pyridyl)terephthalamide (3-bptpa) and 1, 3, 5-benzenetricarboxylic acid (1, 3, 5-H3btc), a Co(Ⅱ) metal-organic framework[Co(3-bptpa)(1, 3, 5-Hbtc)]·2H2O(1) with a 2D grid-like structure was hydrothermally synthesized. Complex 1 was characterized by X-ray crystallography, Fourier transform infrared (FT-IR) spectra, elemental analysis, thermal analysis and magnetic measurements. Each 1, 3, 5-Hbtc2- provided one chelating and one bridging carboxylate groups to coordinate to Co(Ⅱ) cations. The centrosymmetric dimer[Co(3-bptpa)(1, 3, 5-Hbtc)]2 was assembled into a 1D ladder-like chains by bridging carboxylate groups. The neighbouring chains were connected into 2D grid-like network by the coordination of 3-bptpa to Co(Ⅱ), resulting in the distorted CoN2O4 octahedral coordination sphere. The magnetic data of complex 1 in the temperature range 16~300 K were analyzed including the one-ion approximation for Co(Ⅱ) with spin-orbit coupling in Oh symmetry and intermolecular exchange interaction(zj') in the molecular field approximation leading to λ=-100.4 cm-1 and zj'=-0.618 cm-1.
Based on N, N'-bis-(3-pyridyl)terephthalamide (3-bptpa) and 1, 3, 5-benzenetricarboxylic acid (1, 3, 5-H3btc), a Co(Ⅱ) metal-organic framework[Co(3-bptpa)(1, 3, 5-Hbtc)]·2H2O(1) with a 2D grid-like structure was hydrothermally synthesized. Complex 1 was characterized by X-ray crystallography, Fourier transform infrared (FT-IR) spectra, elemental analysis, thermal analysis and magnetic measurements. Each 1, 3, 5-Hbtc2- provided one chelating and one bridging carboxylate groups to coordinate to Co(Ⅱ) cations. The centrosymmetric dimer[Co(3-bptpa)(1, 3, 5-Hbtc)]2 was assembled into a 1D ladder-like chains by bridging carboxylate groups. The neighbouring chains were connected into 2D grid-like network by the coordination of 3-bptpa to Co(Ⅱ), resulting in the distorted CoN2O4 octahedral coordination sphere. The magnetic data of complex 1 in the temperature range 16~300 K were analyzed including the one-ion approximation for Co(Ⅱ) with spin-orbit coupling in Oh symmetry and intermolecular exchange interaction(zj') in the molecular field approximation leading to λ=-100.4 cm-1 and zj'=-0.618 cm-1.
Characterization of Microscopic Structure of Nafion in Dispersion Using Small Angle X-Ray Scattering
2019, 36(12): 1406-1412
doi: 10.11944/j.issn.1000-0518.2019.12.190222
Abstract:
Small angle X-ray scattering was used to characterize the microscopic structure of Nafion in its dispersion composed by different volume ratios of N-methylformamide and n-butanol. The results show that Nafion forms typical micelle structures in its dispersion, because of the synergistic effect of rigidity of main chain and hydrophobicity/hydrophilicity of main/side chain. The radius of gyration(Rg) of micelles exhibits the scale of -0.42 as the increase of Nafion mass concentration, which is in consistent with the theoretical scale of polyelectrolyte in salt free solvents. The correlation length between micelles shows a scale of -0.13, identical to the theoretical scale of typical neutral polymer solutions. Lower polarity n-butanol promotes the formation of long micelles, while high polarity N-methylformamide promotes the dispersion of Nafion. This study provides a clear guidance for understanding the properties of Nafion dispersions and the formation of micro-structure of Nafion films prepared by wet method.
Small angle X-ray scattering was used to characterize the microscopic structure of Nafion in its dispersion composed by different volume ratios of N-methylformamide and n-butanol. The results show that Nafion forms typical micelle structures in its dispersion, because of the synergistic effect of rigidity of main chain and hydrophobicity/hydrophilicity of main/side chain. The radius of gyration(Rg) of micelles exhibits the scale of -0.42 as the increase of Nafion mass concentration, which is in consistent with the theoretical scale of polyelectrolyte in salt free solvents. The correlation length between micelles shows a scale of -0.13, identical to the theoretical scale of typical neutral polymer solutions. Lower polarity n-butanol promotes the formation of long micelles, while high polarity N-methylformamide promotes the dispersion of Nafion. This study provides a clear guidance for understanding the properties of Nafion dispersions and the formation of micro-structure of Nafion films prepared by wet method.
2019, 36(12): 1413-1421
doi: 10.11944/j.issn.1000-0518.2019.12.190077
Abstract:
The adsorption of lanthanum on Ca-montmorillonite was studied. The crystal structure, surface morphology, specific surface area and chemical structure of Ca-montmorillonite were characterized by XRD, SEM, BET, Fourier transform infrared spectrum (FT-IR) and X-Ray fluorescence (XRF). The effects of initial lanthanum concentration, pH and adsorption temperature on the adsorption of La onto Ca-montmorillonite were examined when the mass concentration of Ca-montmorillonite was 10 g/L. The phosphorus removal effect of Ca-MMT@La was studied. The results showed that the adsorption of La onto Ca-montmorillonite increases with initial lanthanum concentration increasing, and the maximum adsorption capacity is 49.62 mg/g. With the increase of the pH of lanthanum-containing solution, the adsorption capacity increases and the optimum adsorption is obtained at initial pH 6 with the adsorption capacity of 38.36 mg/g. With the increase of temperature, the adsorption capacity increases firstly and then decreases. The maximum adsorption capacity of lanthanum is 41.23 mg/g at 20℃. The adsorption equilibrium was best described by the Langmuir isotherm model. The result indicated that La is adsorbed onto Ca-montmorillonite through the monolayer adsorption. Ca-montmorillonite can not adsorb phosphorus. However, Ca-MMT@La has a strong adsorption capacity for phosphate with the adsorption capacity of 7.24 mg/g and the phosphorus removal rate of 72.41%. The adsorption of phosphorus onto Ca-MMT@La increases with the increase of loaded lanthanum content.
The adsorption of lanthanum on Ca-montmorillonite was studied. The crystal structure, surface morphology, specific surface area and chemical structure of Ca-montmorillonite were characterized by XRD, SEM, BET, Fourier transform infrared spectrum (FT-IR) and X-Ray fluorescence (XRF). The effects of initial lanthanum concentration, pH and adsorption temperature on the adsorption of La onto Ca-montmorillonite were examined when the mass concentration of Ca-montmorillonite was 10 g/L. The phosphorus removal effect of Ca-MMT@La was studied. The results showed that the adsorption of La onto Ca-montmorillonite increases with initial lanthanum concentration increasing, and the maximum adsorption capacity is 49.62 mg/g. With the increase of the pH of lanthanum-containing solution, the adsorption capacity increases and the optimum adsorption is obtained at initial pH 6 with the adsorption capacity of 38.36 mg/g. With the increase of temperature, the adsorption capacity increases firstly and then decreases. The maximum adsorption capacity of lanthanum is 41.23 mg/g at 20℃. The adsorption equilibrium was best described by the Langmuir isotherm model. The result indicated that La is adsorbed onto Ca-montmorillonite through the monolayer adsorption. Ca-montmorillonite can not adsorb phosphorus. However, Ca-MMT@La has a strong adsorption capacity for phosphate with the adsorption capacity of 7.24 mg/g and the phosphorus removal rate of 72.41%. The adsorption of phosphorus onto Ca-MMT@La increases with the increase of loaded lanthanum content.
2019, 36(12): 1422-1429
doi: 10.11944/j.issn.1000-0518.2019.12.190272
Abstract:
Because of its high cyclic stability and good energy density, supercapacitor has become a research hotspot in energy storage devices. Electrode materials are the key factors to determine the electrochemical performance of supercapacitors. In this paper, Using poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (P123) as a soft template, graphene/polypyrrole nanofiber (GR/PPy NF) composite supercapacitor electrode materials were successfully prepared by one-step in situ chemical oxidation polymerization. The structure and morphology of composite materials were systematically characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and Fourier transform infrared spectrometer (FT-IR). The electrochemical properties of GR/PPy NF composite electrode materials were systematically analyzed by electrochemical methods. The results reveal that at the current density of 0.5 A/g, the nanocomposite has a maximum capacitance of 969.5 F/g, and can retain 88% of the initial capacitance after 600 cycles of charge and discharge, showing good cyclic stability and excellent electrochemical performance for the electrode materials of supercapacitor. The facile preparation and excellent performance of the GR/PPy NF make it a promising material for energy conversion/storage application.
Because of its high cyclic stability and good energy density, supercapacitor has become a research hotspot in energy storage devices. Electrode materials are the key factors to determine the electrochemical performance of supercapacitors. In this paper, Using poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (P123) as a soft template, graphene/polypyrrole nanofiber (GR/PPy NF) composite supercapacitor electrode materials were successfully prepared by one-step in situ chemical oxidation polymerization. The structure and morphology of composite materials were systematically characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and Fourier transform infrared spectrometer (FT-IR). The electrochemical properties of GR/PPy NF composite electrode materials were systematically analyzed by electrochemical methods. The results reveal that at the current density of 0.5 A/g, the nanocomposite has a maximum capacitance of 969.5 F/g, and can retain 88% of the initial capacitance after 600 cycles of charge and discharge, showing good cyclic stability and excellent electrochemical performance for the electrode materials of supercapacitor. The facile preparation and excellent performance of the GR/PPy NF make it a promising material for energy conversion/storage application.
2019, 36(12): 1430-1438
doi: 10.11944/j.issn.1000-0518.2019.12.190106
Abstract:
As a high temperature gas cooled reactor fuel element, matrix graphite is a porous composite material that is a major component of the fuel element. The structure of matrix graphite affects the performance of the fuel element and the diffusion of fission products inside. In this paper, the pore structure of matrix graphite was characterized by mercury intrusion method, and the influences of the maximum pressing pressure in the preparation process and further heat treatment process on the pore structure of matrix graphite were discussed. The results show that the pore size of large pores in the matrix graphite is 600~1900 nm. High-temperature heat treatment reduces the total porosity, the median pore diameter and the volume of large pores in the matrix graphite. The volume of large pores in the matrix graphite decreases linearly with the increase of the maximum pressing pressure in preparation process. Meanwhile, the diffusion rate of Ag in the graphite matrix has a positive correlation with the variation of the pore volume during high-temperature heat treatment.
As a high temperature gas cooled reactor fuel element, matrix graphite is a porous composite material that is a major component of the fuel element. The structure of matrix graphite affects the performance of the fuel element and the diffusion of fission products inside. In this paper, the pore structure of matrix graphite was characterized by mercury intrusion method, and the influences of the maximum pressing pressure in the preparation process and further heat treatment process on the pore structure of matrix graphite were discussed. The results show that the pore size of large pores in the matrix graphite is 600~1900 nm. High-temperature heat treatment reduces the total porosity, the median pore diameter and the volume of large pores in the matrix graphite. The volume of large pores in the matrix graphite decreases linearly with the increase of the maximum pressing pressure in preparation process. Meanwhile, the diffusion rate of Ag in the graphite matrix has a positive correlation with the variation of the pore volume during high-temperature heat treatment.
An Ion-Selective Microelectrode Method for In-situ Measurement of the Diffusion Coefficients of Ions
2019, 36(12): 1439-1446
doi: 10.11944/j.issn.1000-0518.2019.12.190111
Abstract:
Diffusion coefficient is an important parameter describing the diffusion process of a substance. However, the existing methods such as the membrane pool method, radioactive or fluorescent tracer method, and molecular dynamics simulation cannot be used to measure the ion diffusion coefficient in the biological system in real time. The ion-selective microelectrode has the advantages of rapid response, high selectivity, high sensitivity, high spatial resolution, and no pollution to the sample. Using the advantages of microelectrodes, this paper established the corresponding point source diffusion model by analyzing the ion concentration pulse signal formed by the rupture of protoplasts of single plant cells in culture medium, and derived the theoretical formula describing the ion concentration change with time. By fitting the experimentally measured pulse signal to obtain the diffusion coefficient of ions, a new method for in situ determination of ion diffusion coefficient by ion-selective microelectrode was established and applied to aloe cell protoplasts. When the ion diffusion coefficient is measured during the body rupture, the diffusion coefficients of Ca2+, Na+ and K+ are (6.51±0.12)×10-6 cm2/s, (2.93±0.15)×10-5 cm2/s and (3.03±0.35)×10-5 cm2/s, respectively. The results show that the Ca2+, Na+, and K+ diffusion coefficients obtained are slightly higher than those reported values (in pure water). This phenomenon might be caused by the increase of the intracellular pressure of the protoplasts in the hypotonic fluid. The increased pressure might have accelerated the diffusion of ions when the cell ruptured. This method does not interfere with the biological system, and better solves the problem of in-situ real-time measurement of ion diffusion coefficient in biological systems.
Diffusion coefficient is an important parameter describing the diffusion process of a substance. However, the existing methods such as the membrane pool method, radioactive or fluorescent tracer method, and molecular dynamics simulation cannot be used to measure the ion diffusion coefficient in the biological system in real time. The ion-selective microelectrode has the advantages of rapid response, high selectivity, high sensitivity, high spatial resolution, and no pollution to the sample. Using the advantages of microelectrodes, this paper established the corresponding point source diffusion model by analyzing the ion concentration pulse signal formed by the rupture of protoplasts of single plant cells in culture medium, and derived the theoretical formula describing the ion concentration change with time. By fitting the experimentally measured pulse signal to obtain the diffusion coefficient of ions, a new method for in situ determination of ion diffusion coefficient by ion-selective microelectrode was established and applied to aloe cell protoplasts. When the ion diffusion coefficient is measured during the body rupture, the diffusion coefficients of Ca2+, Na+ and K+ are (6.51±0.12)×10-6 cm2/s, (2.93±0.15)×10-5 cm2/s and (3.03±0.35)×10-5 cm2/s, respectively. The results show that the Ca2+, Na+, and K+ diffusion coefficients obtained are slightly higher than those reported values (in pure water). This phenomenon might be caused by the increase of the intracellular pressure of the protoplasts in the hypotonic fluid. The increased pressure might have accelerated the diffusion of ions when the cell ruptured. This method does not interfere with the biological system, and better solves the problem of in-situ real-time measurement of ion diffusion coefficient in biological systems.
2019, 36(12): 1447-1455
doi: 10.11944/j.issn.1000-0518.2019.12.190084
Abstract:
Three colorimetric sensors S1, S2 and S3 based on azobenzene containing different numbers of active phenolic hydroxyl groups have been designed and synthesized. The sensors in CH3CN exhibit high sensitivity toward F-, H2PO4- and AcO-. The detection limit of S1, S2 and S3 was determined to be 1.25×10-7~3.62×10-7 mol/L for F-. The sensitivity of sensors S1, S2 and S3 for anions were affected by the configuration, charge density and basicity of anions. 1H NMR titration has been performed to study reaction mechanism, which was considered to be direct consequence of hydrogen-bonding between the phenolic group of sensor and anion.
Three colorimetric sensors S1, S2 and S3 based on azobenzene containing different numbers of active phenolic hydroxyl groups have been designed and synthesized. The sensors in CH3CN exhibit high sensitivity toward F-, H2PO4- and AcO-. The detection limit of S1, S2 and S3 was determined to be 1.25×10-7~3.62×10-7 mol/L for F-. The sensitivity of sensors S1, S2 and S3 for anions were affected by the configuration, charge density and basicity of anions. 1H NMR titration has been performed to study reaction mechanism, which was considered to be direct consequence of hydrogen-bonding between the phenolic group of sensor and anion.
2019, 36(12): 1456-1461
doi: 10.11944/j.issn.1000-0518.2019.12.190099
Abstract:
A new turn-on type of luminescence probe based on ruthenium(Ⅱ) complex, [Ru(5-CHO-phen)3]2+(5-CHO-phen=1, 10-phenanthroline-5-carbaldehyde), has been designed and synthesized. The probe displayed good sensitivity and selectivity toward cysteine (Cys) and homocysteine (Hcy). Enhanced luminescence intensity of this probe displays a good linear relationship in the concentration range of 5 to 35 μmol/L for Cys and Hcy. The detection limit is 0.60 μmol/L and 0.78 μmol/L for Cys and Hcy, respectively. The proposed approach provides a useful method by using luminescence probe based on ruthenoium(Ⅱ) complex for the quantitative detection of various biological molecules.
A new turn-on type of luminescence probe based on ruthenium(Ⅱ) complex, [Ru(5-CHO-phen)3]2+(5-CHO-phen=1, 10-phenanthroline-5-carbaldehyde), has been designed and synthesized. The probe displayed good sensitivity and selectivity toward cysteine (Cys) and homocysteine (Hcy). Enhanced luminescence intensity of this probe displays a good linear relationship in the concentration range of 5 to 35 μmol/L for Cys and Hcy. The detection limit is 0.60 μmol/L and 0.78 μmol/L for Cys and Hcy, respectively. The proposed approach provides a useful method by using luminescence probe based on ruthenoium(Ⅱ) complex for the quantitative detection of various biological molecules.
2019, 36(12): 1462-1464
doi: 10.11944/j.issn.1000-0518.2019.12.190133
Abstract:
α-FeO(OH) was prepared and characterized. The effects of low relative molecular mass organic acids(LMW) in soils on the adsorption of As(Ⅲ) by α-FeO(OH) were investigated, and the mechanism was elucidated. Single LMW and mixed LMW have inhibitory effect on the adsorption of As(Ⅲ) by α-FeO(OH). The influence order of four LMW on the adsorption of As(Ⅲ) by α-FeO(OH is as follows:oxalic acid (OA) > citric acid (CA) > lactic acid (LA), salicylic acid (SA). The effect of mixed LMW on the adsorption of As(Ⅲ) by α-FeO(OH) is as follows:the OA aggravates the effect of CA on the adsorption of As(Ⅲ) by α-FeO(OH), and addition of SA hardly affects the adsorption of As(Ⅲ) by α-FeO(OH). When the ρ(As(Ⅲ)) is low, the electrostatic attraction of LMW with α-FeO(OH), the formation of complexes with iron ions on the surface of α-FeO(OH), and the formation of precipitates affect the adsorption of As (Ⅲ) by α-FeO(OH). When the ρ(As (Ⅲ)) is high, the LMW affects the diffusion and precipitation of As(Ⅲ). The experimental results provide technical support for the migration, transformation, and pollution control of As(Ⅲ) in soil.
α-FeO(OH) was prepared and characterized. The effects of low relative molecular mass organic acids(LMW) in soils on the adsorption of As(Ⅲ) by α-FeO(OH) were investigated, and the mechanism was elucidated. Single LMW and mixed LMW have inhibitory effect on the adsorption of As(Ⅲ) by α-FeO(OH). The influence order of four LMW on the adsorption of As(Ⅲ) by α-FeO(OH is as follows:oxalic acid (OA) > citric acid (CA) > lactic acid (LA), salicylic acid (SA). The effect of mixed LMW on the adsorption of As(Ⅲ) by α-FeO(OH) is as follows:the OA aggravates the effect of CA on the adsorption of As(Ⅲ) by α-FeO(OH), and addition of SA hardly affects the adsorption of As(Ⅲ) by α-FeO(OH). When the ρ(As(Ⅲ)) is low, the electrostatic attraction of LMW with α-FeO(OH), the formation of complexes with iron ions on the surface of α-FeO(OH), and the formation of precipitates affect the adsorption of As (Ⅲ) by α-FeO(OH). When the ρ(As (Ⅲ)) is high, the LMW affects the diffusion and precipitation of As(Ⅲ). The experimental results provide technical support for the migration, transformation, and pollution control of As(Ⅲ) in soil.
