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Aiqin Wang - One of the best experts on this subject based on the ideXlab platform.
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Palygorskite Nanomaterials: Structure, Properties, and Functional Applications
Nanomaterials from Clay Minerals, 2020Co-Authors: Wenbo Wang, Aiqin WangAbstract:Abstract One-dimensional (1D) nanomaterials play very important roles in the fields of modern industry, engineering, and functional materials. When people have to pay a very high price to synthesize 1D nanomaterial, the naturally produced nanomaterials with diverse morphologies, applicability, and environmentally friendly advantages are gradually attracting attention. Palygorskite is a naturally available 1D nanomaterial with a special rod-like crystal structure, excellent properties, and abundant reserves in nature; it has shown great application potential in many fields, including the chemical, environmental protection, functional material, biomedicine, and building material industries. In recent years, the rapid development and application of modern nanotechnology make it possible to transform the Palygorskite minerals into highly dispersed 1D nanorods by a physical/or chemical disassociation or splitting process of Palygorskite crystal bundles or aggregates, which enable it to be used in the area of high-performance functional materials. This chapter expounds the mineral occurrence, resource distribution, crystal structure, microscopic morphology, and physicochemical features of Palygorskite. Mainly summarized, the recent research progress on the dispersion of crystal bundles or aggregates of natural Palygorskite, the surface modifications of Palygorskite, structure evolution, and regulation of Palygorskite and associated minerals, as well as their applications as “green” components to fabricate a variety of new functional materials. The development trends of Palygorskite-based materials and their future potential applications in advanced functional materials are discussed in general and are drawn from scientific literature. This chapter will arouse more attention for the key role Palygorskite can play in developing various micro/nano functional materials.
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Fabrication of ZnO/Palygorskite Nanocomposites for Antibacterial Application
Springer Proceedings in Earth and Environmental Sciences, 2019Co-Authors: Yuru Kang, Aiqin WangAbstract:ZnO/Palygorskite nanocomposites were synthesized by chemical deposition and calcination process for antibacterial application. The results indicated that ZnO nanoparticles were deposited on the surface of rod-like Palygorskite. Antibacterial evaluation confirmed that ZnO/PAL nanocomposites presented the good antibacterial behavior against Escherichia coli and Staphylococcus aureus, which was mainly attributed to the synergistic effect of ZnO and Palygorskite.
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adsorption of dyes onto Palygorskite and its composites a review
Journal of environmental chemical engineering, 2016Co-Authors: Bin Mu, Aiqin WangAbstract:Abstract With the continuous increase in the demand of dyes, the dye wastewater is becoming a major environmental threat. Adsorption techniques are widely used to remove dyes from wastewater using clay minerals, especially a naturally available one-dimensional Palygorskite due to high surface area, moderate cation exchange capacity, excellent salt resistance compared with other clay minerals. Although the maximum adsorption of natural Palygorskite toward dyes far exceeded the cation exchange capacity of Palygorskite, it is difficult to completely release the adsorption capacity of Palygorskite toward dyes due to the existence of the bulk crystal bundles or aggregates originated from the interparticle Van der Waals’ and hydrogen bonding interactions. Therefore, it is indispensible to disaggregate Palygorskite crystal bundles and introduce functional groups to improve the microscopic structure of Palygorskite and increase the adsorption sites via various physical and chemical modifications. This review article summarizes the development on the modified Palygorskite with different physical or chemical methods and Palygorskite-based composite used as adsorbents for the adsorption of dyes from aqueous solution by reviewing a comprehensive literature combined with our group’s research achievements. In addition, few conclusions and suggestions have been proposed for future research.
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a comparative study about adsorption of natural Palygorskite for methylene blue
Chemical Engineering Journal, 2015Co-Authors: Yuan Zhang, Wenbo Wang, Junping Zhang, Aiqin WangAbstract:Abstract Various methods including acid treatment, heat treatment and surface modification have been used to improve the adsorption properties of natural Palygorskite. However, the comparative study about the effect of source of Palygorskite on the adsorption properties remains a gap to be filled. Here we first studied the structure and chemical composition of three Palygorskite samples from Jiangsu, Anhui and Gansu Provinces of China using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), and X-ray Fluorescence Spectrometry (XRF). Subsequently, the adsorption properties of the Palygorskites for methylene blue (MB) were evaluated and compared. The Palygorskite from Jiangsu (JSHS) is Mg-poor and has an analogous dioctahedral structure. The Palygorskite from Anhui (AHGS) is Mg-rich, and has an intermediate structure of dioctahedron and trioctahedron. The Palygorskite from Gansu (GSHN) also has an intermediate structure of dioctahedron and trioctahedron, but is associated with muscovite, clinochlore, dolomite and feldspar. The maximum adsorption capacity of the Palygorskites from JSHS, GSHN, AHGS for MB at 303 K is 158.03, 98.34, 77.92 mg/g, respectively. It was found that a lower Mg content and the dioctahedral structure of Palygorskite are favorable to its adsorption for MB. More negative value of Gibbs free energy (△ G 0 ) for JSHS further illustrates that JSHS has higher efficiency in removing the MB molecules than the others. The adsorption mechanism studies suggest that the zeolitic H 2 O plays a fundamental role in the interaction between MB and Palygorskite.
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Effect of Solvents Treatment on Microstructure and Dispersion Properties of Palygorskite
Journal of Dispersion Science and Technology, 2013Co-Authors: Jixiang Xu, Wenbo Wang, Aiqin WangAbstract:Palygorskite was dispersed by various organic solvents and water, and the effects of solvent types on its microstructure, dispersion degree, and colloidal properties were investigated by infrared spectroscopy (IR), x-ray diffraction (XRD), and nitrogen adsorption-desorption isotherm (BET), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and rheological analyses. It was found that dimethyl sulfoxide and dimethyl formamide molecules may attach onto the surface of Palygorskite and cause a complete disappearance of micropores. Solvent parameters govern the dispersion degree of Palygorskite, and dimethyl sulfoxide and dimethyl formamide are good solvents to disperse Palygorskite aggregates in contrast to ethanol and isopropanol. Colloidal stability and rheological tests suggested dimethyl sulfoxide-dispersed Palygorskite can form more stable suspension with higher shear stress and modulus, but isopropanol-dispersed Palygorskite may rapidly subside in suspension and ...
Jixiang Xu - One of the best experts on this subject based on the ideXlab platform.
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Effect of Solvents Treatment on Microstructure and Dispersion Properties of Palygorskite
Journal of Dispersion Science and Technology, 2013Co-Authors: Jixiang Xu, Wenbo Wang, Aiqin WangAbstract:Palygorskite was dispersed by various organic solvents and water, and the effects of solvent types on its microstructure, dispersion degree, and colloidal properties were investigated by infrared spectroscopy (IR), x-ray diffraction (XRD), and nitrogen adsorption-desorption isotherm (BET), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and rheological analyses. It was found that dimethyl sulfoxide and dimethyl formamide molecules may attach onto the surface of Palygorskite and cause a complete disappearance of micropores. Solvent parameters govern the dispersion degree of Palygorskite, and dimethyl sulfoxide and dimethyl formamide are good solvents to disperse Palygorskite aggregates in contrast to ethanol and isopropanol. Colloidal stability and rheological tests suggested dimethyl sulfoxide-dispersed Palygorskite can form more stable suspension with higher shear stress and modulus, but isopropanol-dispersed Palygorskite may rapidly subside in suspension and ...
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effects of solvent treatment and high pressure homogenization process on dispersion properties of Palygorskite
Powder Technology, 2013Co-Authors: Jixiang Xu, Wenbo Wang, Aiqin WangAbstract:Dispersion of natural Palygorskite in distilled water, methanol, ethanol, isopropanol, dimethyl formamide, and dimethyl sulfoxide was carried out using high-pressure homogenization. The effects of solvent parameters on the microstructure, morphology and colloidal properties of Palygorskite were investigated in detail. Elemental analysis, infrared spectroscopy (IR) and thermogravimetric analysis (TGA) confirmed that some solvent molecules were encapsulated within the tunnels of Palygorskite. The efficiency of the homogenization process to disperse Palygorskite aggregates was closely correlated to the solvent parameters, particularly solvent vapor pressure and viscosity. A well disaggregated Palygorskite was obtained after dispersing in dimethyl sulfoxide. It was also confirmed that colloidal stability and suspension viscosity were affected by the solvent nature. A more stable suspension with higher viscosity of 2364 mPa s was obtained by dispersing Palygorskite in isopropanol.
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effects of inorganic sulfates on the microstructure and properties of ion exchange treated Palygorskite clay
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2012Co-Authors: Jixiang Xu, Wenbo Wang, Bin Mu, Aiqin WangAbstract:Abstract Palygorskite was modified with inorganic sulfates, including Na2SO4, ZnSO4, Al2(SO4)3, and Zr(SO4)2, using the high-pressure homogenization technology. The effects of type and concentration of sulfates on the morphology, micro-structure, surface potential, shear modulus and viscosity of Palygorskite were investigated by scanning electron microscopy (SEM), nitrogen adsorption–desorption isotherms (BET), zeta potential and rheological measurements, respectively. The modification of Palygorskite with ZnSO4 increased its specific surface area and micropore volume, but the largest pore size was obtained for the Palygorskite modified with Al2(SO4)3. Zeta potential results suggested that the multivalent Al3+ and Zr4+ ions were more efficient in reducing the negative charge of Palygorskite. The colloidal properties of the suspension were dependent on the type and concentration of sulfates, and the introduction of ZnSO4 simultaneously enhanced the dispersibility and colloidal properties of Palygorskite.
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disaggregation of Palygorskite crystal bundles via high pressure homogenization
Applied Clay Science, 2011Co-Authors: Jixiang Xu, Junping Zhang, Qin Wang, Aiqin WangAbstract:Abstract A simple and effective method, high-pressure homogenization, for the disaggregation of Palygorskite crystal bundles was reported. The effects of high-pressure homogenization on the structure and properties of Palygorskite clay were investigated. The Palygorskite crystal bundles were disaggregated very well while keeping the intrinsic aspect ratio of the microfibers after homogenized at 50 MPa. Compared to natural Palygorskite, the specific surface area (from 192 m2/g to 246 m2/g), micropore surface area (from 72 m2/g to 110 m2/g) and micropore volume (from 0.033 cm3/g to 0.051 cm3/g) of Palygorskite were clearly enhanced after homogenization. In addition, a perfect dispersion of Palygorskite fibers was obtained after homogenized at 90 MPa.
Wenbo Wang - One of the best experts on this subject based on the ideXlab platform.
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Palygorskite Nanomaterials: Structure, Properties, and Functional Applications
Nanomaterials from Clay Minerals, 2020Co-Authors: Wenbo Wang, Aiqin WangAbstract:Abstract One-dimensional (1D) nanomaterials play very important roles in the fields of modern industry, engineering, and functional materials. When people have to pay a very high price to synthesize 1D nanomaterial, the naturally produced nanomaterials with diverse morphologies, applicability, and environmentally friendly advantages are gradually attracting attention. Palygorskite is a naturally available 1D nanomaterial with a special rod-like crystal structure, excellent properties, and abundant reserves in nature; it has shown great application potential in many fields, including the chemical, environmental protection, functional material, biomedicine, and building material industries. In recent years, the rapid development and application of modern nanotechnology make it possible to transform the Palygorskite minerals into highly dispersed 1D nanorods by a physical/or chemical disassociation or splitting process of Palygorskite crystal bundles or aggregates, which enable it to be used in the area of high-performance functional materials. This chapter expounds the mineral occurrence, resource distribution, crystal structure, microscopic morphology, and physicochemical features of Palygorskite. Mainly summarized, the recent research progress on the dispersion of crystal bundles or aggregates of natural Palygorskite, the surface modifications of Palygorskite, structure evolution, and regulation of Palygorskite and associated minerals, as well as their applications as “green” components to fabricate a variety of new functional materials. The development trends of Palygorskite-based materials and their future potential applications in advanced functional materials are discussed in general and are drawn from scientific literature. This chapter will arouse more attention for the key role Palygorskite can play in developing various micro/nano functional materials.
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a comparative study about adsorption of natural Palygorskite for methylene blue
Chemical Engineering Journal, 2015Co-Authors: Yuan Zhang, Wenbo Wang, Junping Zhang, Aiqin WangAbstract:Abstract Various methods including acid treatment, heat treatment and surface modification have been used to improve the adsorption properties of natural Palygorskite. However, the comparative study about the effect of source of Palygorskite on the adsorption properties remains a gap to be filled. Here we first studied the structure and chemical composition of three Palygorskite samples from Jiangsu, Anhui and Gansu Provinces of China using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), and X-ray Fluorescence Spectrometry (XRF). Subsequently, the adsorption properties of the Palygorskites for methylene blue (MB) were evaluated and compared. The Palygorskite from Jiangsu (JSHS) is Mg-poor and has an analogous dioctahedral structure. The Palygorskite from Anhui (AHGS) is Mg-rich, and has an intermediate structure of dioctahedron and trioctahedron. The Palygorskite from Gansu (GSHN) also has an intermediate structure of dioctahedron and trioctahedron, but is associated with muscovite, clinochlore, dolomite and feldspar. The maximum adsorption capacity of the Palygorskites from JSHS, GSHN, AHGS for MB at 303 K is 158.03, 98.34, 77.92 mg/g, respectively. It was found that a lower Mg content and the dioctahedral structure of Palygorskite are favorable to its adsorption for MB. More negative value of Gibbs free energy (△ G 0 ) for JSHS further illustrates that JSHS has higher efficiency in removing the MB molecules than the others. The adsorption mechanism studies suggest that the zeolitic H 2 O plays a fundamental role in the interaction between MB and Palygorskite.
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Effect of Solvents Treatment on Microstructure and Dispersion Properties of Palygorskite
Journal of Dispersion Science and Technology, 2013Co-Authors: Jixiang Xu, Wenbo Wang, Aiqin WangAbstract:Palygorskite was dispersed by various organic solvents and water, and the effects of solvent types on its microstructure, dispersion degree, and colloidal properties were investigated by infrared spectroscopy (IR), x-ray diffraction (XRD), and nitrogen adsorption-desorption isotherm (BET), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and rheological analyses. It was found that dimethyl sulfoxide and dimethyl formamide molecules may attach onto the surface of Palygorskite and cause a complete disappearance of micropores. Solvent parameters govern the dispersion degree of Palygorskite, and dimethyl sulfoxide and dimethyl formamide are good solvents to disperse Palygorskite aggregates in contrast to ethanol and isopropanol. Colloidal stability and rheological tests suggested dimethyl sulfoxide-dispersed Palygorskite can form more stable suspension with higher shear stress and modulus, but isopropanol-dispersed Palygorskite may rapidly subside in suspension and ...
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effects of solvent treatment and high pressure homogenization process on dispersion properties of Palygorskite
Powder Technology, 2013Co-Authors: Jixiang Xu, Wenbo Wang, Aiqin WangAbstract:Dispersion of natural Palygorskite in distilled water, methanol, ethanol, isopropanol, dimethyl formamide, and dimethyl sulfoxide was carried out using high-pressure homogenization. The effects of solvent parameters on the microstructure, morphology and colloidal properties of Palygorskite were investigated in detail. Elemental analysis, infrared spectroscopy (IR) and thermogravimetric analysis (TGA) confirmed that some solvent molecules were encapsulated within the tunnels of Palygorskite. The efficiency of the homogenization process to disperse Palygorskite aggregates was closely correlated to the solvent parameters, particularly solvent vapor pressure and viscosity. A well disaggregated Palygorskite was obtained after dispersing in dimethyl sulfoxide. It was also confirmed that colloidal stability and suspension viscosity were affected by the solvent nature. A more stable suspension with higher viscosity of 2364 mPa s was obtained by dispersing Palygorskite in isopropanol.
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effects of inorganic sulfates on the microstructure and properties of ion exchange treated Palygorskite clay
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2012Co-Authors: Jixiang Xu, Wenbo Wang, Bin Mu, Aiqin WangAbstract:Abstract Palygorskite was modified with inorganic sulfates, including Na2SO4, ZnSO4, Al2(SO4)3, and Zr(SO4)2, using the high-pressure homogenization technology. The effects of type and concentration of sulfates on the morphology, micro-structure, surface potential, shear modulus and viscosity of Palygorskite were investigated by scanning electron microscopy (SEM), nitrogen adsorption–desorption isotherms (BET), zeta potential and rheological measurements, respectively. The modification of Palygorskite with ZnSO4 increased its specific surface area and micropore volume, but the largest pore size was obtained for the Palygorskite modified with Al2(SO4)3. Zeta potential results suggested that the multivalent Al3+ and Zr4+ ions were more efficient in reducing the negative charge of Palygorskite. The colloidal properties of the suspension were dependent on the type and concentration of sulfates, and the introduction of ZnSO4 simultaneously enhanced the dispersibility and colloidal properties of Palygorskite.
Yunfei Xi - One of the best experts on this subject based on the ideXlab platform.
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adsorption of the herbicide 2 4 d on organo Palygorskite
Applied Clay Science, 2010Co-Authors: Yunfei Xi, Megharaj Mallavarapu, Ravendra NaiduAbstract:Among the clay minerals, montmorillonite is the most extensively studied material using as adsorbents, but Palygorskite and its organically modified products have been least explored for their potential use in contaminated water remediation. In this study, an Australian Palygorskite was modified with cationic surfactants octadecyl trimethylammonium bromide and dioctadecyl dimethylammonium bromide at different doses. A full structural characterization of prepared organo-Palygorskite by X-ray diffraction, infrared spectroscopy, surface analysis and thermogravimetric analysis was performed. The morphological changes of Palygorskite before and after modification were recorded using scanning electron microscopy, which showed the surfactant molecules can attach on the surface of rod-like crystals and thus can weaken the interactions between Palygorskite single crystals. Real surfactants loadings on organo-Palygorskites were also calculated based on thermogravimetric analysis. 1 CEC, 2 CEC octadecyl trimethylammonium bromide modified Palygorskites, 1 CEC and 2 CEC dioctadecyl dimethylammonium bromide modified Palygorskites absorbed as much as 12 mg/g, 42 mg/g, 9 mg/g and 25 mg/g of 2,4-dichlorophenoxyacetic acid respectively. This study has shown a potential on organo-Palygorskites for organic herbicide adsorption especially anionic ones from waste water. In addition, equilibration time effects and the Langmuir and Freundlich models fitting were also investigated in details.
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synthesis characterization of Palygorskite supported zero valent iron and its application for methylene blue adsorption
Journal of Colloid and Interface Science, 2010Co-Authors: Ray L. Frost, Yunfei Xi, Hongping HeAbstract:In this work, natural Palygorskite impregnated with zero-valent iron (ZVI) was prepared and characterized. The combination of ZVI particles on surface of fibrous Palygorskite can help to overcome the disadvantage of ultra-fine powders which may have strong tendency to agglomerate into larger particles, resulting in an adverse effect on both effective surface area and catalyst performance. There is a significant increase of methylene blue (MB) decolourized efficiency on acid treated Palygorskite with ZVI grafted, within 5 min, the concentration of MB in the solution was decreased from 94 mg/L to around 20 mg/L and the equilibration was reached at about 30-60 min with only around 10 mg/L MB remained in solution. Changes in the surface and structure of prepared materials were characterized using X-ray diffraction (XRD), infrared (IR) spectroscopy, surface analysing and scanning electron microscopy (SEM) with element analysis and mapping. Comparing with zero-valent iron and Palygorskite, the presence of zero-valent iron reactive species on the Palygorskite surface strongly increases the decolourization capacity for methylene blue, and it is significant for providing novel modified clay catalyst materials for the removal of organic contaminants from waste water.
Emilia Garciaromero - One of the best experts on this subject based on the ideXlab platform.
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a combined synchrotron powder diffraction and vibrational study of the thermal treatment of Palygorskite indigo to produce maya blue
Journal of Materials Science, 2009Co-Authors: Enrico Boccaleri, Mercedes Suárez, Vassilis Gionis, George H Kacandes, Marco Milanesio, Gianluca Croce, Wouter Van Beek, Constantinos Tsiantos, Georgios D Chyssikos, Emilia GarciaromeroAbstract:The heating process (30–200 °C) of a Palygorskite-indigo mixture has been monitored in situ and simultaneously by synchrotron powder diffraction and Raman spectroscopy. During this process, the dye and the clay interact to form Maya blue (MB), a pigment highly resistant to degradation. It is shown that the formation of a very stable pigment occurs in the 70–130 °C interval; i.e., when Palygorskite starts to loose zeolitic water, and is accompanied by a reduction of the crystallographic a parameter, as well as by alterations in the C=C and C=O bonds of indigo. Mid- and near-infrared spectroscopic work and microporosity measurements, employed to study the rehydration process after the complex formation, provide evidence for the inhibition of the rehydration of MB as compared with Palygorskite. These results are consistent with the blocking of the Palygorskite tunnel entrance by indigo molecules with a possible partial penetration inside the tunnels. The surface silanols of Palygorskite are not perturbed by indigo, suggesting that MB is not a surface complex.
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octahedral cation distribution in Palygorskite
American Mineralogist, 2009Co-Authors: Georgios D Chryssikos, Mercedes Suárez, Vassilis Gionis, George H Kacandes, Elizabeth T Stathopoulou, Emilia GarciaromeroAbstract:The OH speciation of 18 Palygorskite samples from various localities were evaluated by near infrared spectroscopy (NIR) and compared to the corresponding octahedral composition derived from independent, single-particle analytical electron microscopy (AEM). NIR gives evidence for dioctahedral-like (AlAlOH, AlFe3+OH, Fe3+Fe3+OH) and trioctahedral-like (Mg3OH) species. Therefore, Palygorskite can be approximated by the formula y Mg5 Si8O20(OH)2· (1 − y )[ x Mg2Fe2·(1 − x )Mg2Al2] Si8O20(OH)2, where x is the Fe content of the dioctahedral component, and y is the trioctahedral fraction. The values of x estimated from the NIR data are in excellent agreement with the Fe/(VIAl + Fe) ratio from AEM ( R 2 = 0.98, σ= 0.03), thus suggesting that all octahedral Al and Fe in Palygorskite participate in M2M2OH (dioctahedral-like) arrangements. Furthermore, y values from AEM can be compared to NIR ( R 2 = 0.90 and σ = 0.05) after calibrating the relative intensity of the Mg3OH vs. (Al,Fe)2OH overtone bands using AEM data. The agreement between the spectroscopic and analytical data are excellent. The data show that Fe3+ for Al substitution varies continuously in the analyzed samples over a broad range (0 < x < 0.7), suggesting that fully ferric dioctahedral Palygorskites ( x = 1) may exist. On the other hand, the observed upper trioctahedral limit of y = 0.50 calls for the detailed structural comparison of Mg-rich Palygorskite with sepiolite.
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ftir spectroscopic study of Palygorskite influence of the composition of the octahedral sheet
Applied Clay Science, 2006Co-Authors: Mercedes Suárez, Emilia GarciaromeroAbstract:The influence of chemical composition to position and intensity of the absorption bands observed in the FTIR spectra of Palygorskite has been studied by a detailed comparative study of six samples. Palygorskites studied have high purity and different chemical composition. At one extreme, there are two samples that correspond to Mg-rich Palygorskites, at the other extreme a sample with a composition very close to the theoretical formula of this mineral, and there are three further samples whose structural formulae lie between these extremes. The position of the bands identified in the FTIR spectra of the Palygorskites studied is similar for all samples, but there are some differences in their intensity, which are significant. Analysing these intensities, valuable information about the distribution of cations along the octahedral sheet has been obtained. Isomorphic substitution in octahedral sheet occurs only in M2 position. Al, and Fe may occupy M2 position whereas Mg can occupy all possible sites: M1, M2 and M3.
