Cyanotoxins are chemical compounds produced by cyanobacterial mats grown in aquatic ecosystems. These may threaten human health and aquatic organisms. Extraction of these toxins is usually associated with many difficu...Cyanotoxins are chemical compounds produced by cyanobacterial mats grown in aquatic ecosystems. These may threaten human health and aquatic organisms. Extraction of these toxins is usually associated with many difficulties due to their concentration in aquatic ecosystems. This study is designed to provide suitable and effective extraction procedures that can effectively extract low concentration cyanotoxin from water and bacterial cells. The methodology is based on collecting raw material of cyanobacterial mats from naturally growing sites such as Wadi Gaza along with 16 liters of aquatic surrounding media. The materials were left in the Lab for 24 - 48 h for stabilization of the mats. The floating mats were collected using special funnel and allowed to air drying. The aqueous phase was extracted by liquid/liquid extraction using solvent mixture (hexane + ethylacetate 10% w:w), and by liquid solid extraction using several types of organoclays complexes. The solid phase was extracted by acetone and ultrasonic device. Results showed some difficulties were associated with liquid/liquid extraction whereas effective and easy extraction procedures were obtained by liquid solid extraction using either organoclay complex or activated charcoal. In contrast combination of both solid materials did not show improvement in the extracted cyanotoxin. Thus we recommend the use of organoclays or activated charcoal separately for extracting cyanotoxin. Further improvement of extraction can be tailored by using a specific organoclay complex that has some similarity in the chemical structure between the pre-adsorbed organic cation to the clay mineral and the chemical structure of cyanotoxin.展开更多
Adsorption of phenthoate and acetochlor onto kaolin, montmorillonite, bentonite clays and respective organoclays prepared by the exchange of quaternary ammonium as tetradecyltrimethyl ammonium bromide(TTAB), dodecyltr...Adsorption of phenthoate and acetochlor onto kaolin, montmorillonite, bentonite clays and respective organoclays prepared by the exchange of quaternary ammonium as tetradecyltrimethyl ammonium bromide(TTAB), dodecyltrimethylammonium bromide(DTAB), and cetylpyridinium chloride(CPC) were studied. The adsorption equilibrium data points were fitted to Freundlich isotherm equations. The adsorption of phenthoate and acetochlor were significantly enhanced by surfactant treatment of the clays. The amount of both pesticides adsorbed per unit mass of organoclay followed the order of TTA-kaolin < TTA-montmorillonite < TTA-bentonite, which is inconsistent with the organic carbon content of the clays. The removal efficiency of organomontmorillonite to treat acetochlor is in the order of CP(C 16 )-montmorillonite > TTA(C 14 )-montmorillonite > DTA(C 12 )-montmorillonite. Phenthoate is adsorbed to greater extent than acetochlor by each adsorbent, which may be due to the higher hydrophobicity of phenthoate, indicating considerable hydrophobic interaction between adsorbent/adsorbate systems.展开更多
This work presents a new approach for the fabrication of organic/inorganic nanohybrids as anticancer drugs by an intercalation method using S,S-bis（α,α′-dimethyl-α″-acetic acid） （trithiocarbonate） as a modifi...This work presents a new approach for the fabrication of organic/inorganic nanohybrids as anticancer drugs by an intercalation method using S,S-bis（α,α′-dimethyl-α″-acetic acid） （trithiocarbonate） as a modifier and two organoclays, such as reactive octadecylamine/MMT （montmorillonite） and non-reactive dimethyldidodecyl ammonium/MMT. The chemical and physical structures and the surface morphology of these covalently and non-covalently linked nanohybrids were investigated by FT-IR （Fourier translbrm infrared） spectroscopy, ^13C and ^29Si solid state NMR （nuclear magnetic resonance） spectroscopy, XRD （X-ray powder diffraction） and SEM （scanning electron microscopy） analyses, respectively. To evaluate the anticancer activities of the novel BATC/organoclay hybrids against MCF-7 breast cancer cells, a combination of different biochemical and biophysical testing techniques were used. Cell proliferation and cytotoxicity were detected in vitro using a real-time analysis. Cell death was confirmed by using apoptotic and necrotic analyses, the effects of which were detennined by the double staining and Annexin-V-FLUOS testing method. The results demonstrate that intercalated hybrid complexes containing a combination of various anticancer sites, such as free and complexed carboxyl, trithiocarbonate, amine and ammonium cations significantly induced cell death in breast cancer via their interactions with the DNA macromolecules of cancer cells by destroying the self-assemb｜ed structure of growing cells. Fabricated hybrid complexes may represent a new generation of effective and selective anticancer drug systems with a synthetic/natural origin for cancer chemotherapy.展开更多
Functional copolymer–clay hybrids were synthesized by radical-initiated intercalative copolymerization of maleic acid (MA) and acrylamide (AAm) with 2,2’-azobis (2-methylpropionamidine) dihydrochloride as a water-so...Functional copolymer–clay hybrids were synthesized by radical-initiated intercalative copolymerization of maleic acid (MA) and acrylamide (AAm) with 2,2’-azobis (2-methylpropionamidine) dihydrochloride as a water-soluble ionizable radical initiator in the presence of reactive (octadecyl amine (ODA)-MMT) and non-reactive (dimethyldodecyl ammonium (DMDA)-MMT) organoclays at 50oC in aqueous medium under nitrogen atmosphere. The monomers was dissolved in aqueous medium, as well as both used clay particles were easily dissolved and dispersed with partially swollen in deionized water, respectively. Structure, thermal behavior and morphology of the synthesized nanocomposites were investigated by FTIR, XRD, DSC-TGA, SEM and TEM analysis methods, respectively. It was demonstrated that intercalative copolymerization proceed via ion exchange between organoclays and carboxylic groups of monomers/polymers which essentially improved interfacial interaction of polymer matrix and clay layers through strong H-bonding. In case of intercalative copolymerization in the presence of ODA-MMT clay, similar improvement was provided by in situ hydrogen-bonding and amidolysis of carboxylic/anhydride groups from copolymer chains with primary amine group of ODA-MMT. The nanocomposites exhibit higher intercalation/exfoliation degree of copolymer chains, improved thermal properties and fine dispersed morphology.展开更多
Ethylene copolymers with different polar comonomers,such as vinyl acetate,methyl acrylate,glycidyl methacrylate,and maleic anhydride,were used for the preparation of polymer/clay nanocomposites by statically annealing...Ethylene copolymers with different polar comonomers,such as vinyl acetate,methyl acrylate,glycidyl methacrylate,and maleic anhydride,were used for the preparation of polymer/clay nanocomposites by statically annealing their mechanical mixtures with different commercial or home-made organically modified montmorillonites containing only one long alkyl tail.The nanostructure of the products was monitored by X-ray diffraction,and the dispersion of the silicate particles within the polymer matrix was qualitatively evaluated through microscopic analyses.The effect of the preparation conditions on the structure and the morphology of the composites was also addressed through the characterization of selected samples with similar composition prepared by melt compounding.In agreement with the findings reported in a previous paper for the composites filled with two-tailed organoclays,intercalation of the copolymer chains within the tighter galleries of the one-tailed clays occurs easily,independent of the application of a mechanical stress.However,the shear-driven break-up of the intercalated clay particles into smaller platelets(exfoliation)seems more hindered.A collapse of the organoclay interlayer spacing was only observed clearly for a commercial one-tailed organoclay-Cloisite®30B–whereas the same effect was almost negligible for a home-made organoclay with similar structure.展开更多
The investigation of the environmental properties of minerals, i.e., environmental mineralogy, is a branch of science dealing with interactions between natural minerals and spheres of the Earth surface as well as a re...The investigation of the environmental properties of minerals, i.e., environmental mineralogy, is a branch of science dealing with interactions between natural minerals and spheres of the Earth surface as well as a reflection of global change, prevention of ecological destruction, participation in biomineralogy, and remediation of environmental pollution. Pollutant treatment by natural minerals is based on the natural law and reflects natural self-purification functions in the inorganic world, similar to that of the organic world - a biological treatment. A series of case studies related to natural self-purification, which were mostly completed by our group, are discussed in this paper. In natural cryptomelane there is a larger pseudotetragonal tunnel than that formed by [MnO6] octahedral double chains, with an aperture of 0.462-0.466 nm2, filled with K cations. Cryptomelane might be a real naturally-occurring mineral of the active octahedral molecular sieve (OMS-2). CrⅥ-bearing wastewater can be treated by natural pyrrhotite, which is used as a reductant to reduce CrⅥ and as a precipitant to precipitate CrⅢ simultaneously. Batch experiments were conducted using the CTMAB-Montmorillonite as an adsorbent for aromatic contaminants (phenol, aniline, benzene, toluene and xylenes), which are detected frequently in the leaching water from municipal waste deposits around China. The CTMAB modification has proved very effective to enhance the adsorption capacity of the sorbent. Expansion of vermiculite develops loose interior structures, such as pores or cracks, inside briquettes, and thus brings enough oxygen for combustion and the sulfation reaction. Effective combustion of the original carbon reduces the amount of dust in the fly ash.展开更多
文摘Cyanotoxins are chemical compounds produced by cyanobacterial mats grown in aquatic ecosystems. These may threaten human health and aquatic organisms. Extraction of these toxins is usually associated with many difficulties due to their concentration in aquatic ecosystems. This study is designed to provide suitable and effective extraction procedures that can effectively extract low concentration cyanotoxin from water and bacterial cells. The methodology is based on collecting raw material of cyanobacterial mats from naturally growing sites such as Wadi Gaza along with 16 liters of aquatic surrounding media. The materials were left in the Lab for 24 - 48 h for stabilization of the mats. The floating mats were collected using special funnel and allowed to air drying. The aqueous phase was extracted by liquid/liquid extraction using solvent mixture (hexane + ethylacetate 10% w:w), and by liquid solid extraction using several types of organoclays complexes. The solid phase was extracted by acetone and ultrasonic device. Results showed some difficulties were associated with liquid/liquid extraction whereas effective and easy extraction procedures were obtained by liquid solid extraction using either organoclay complex or activated charcoal. In contrast combination of both solid materials did not show improvement in the extracted cyanotoxin. Thus we recommend the use of organoclays or activated charcoal separately for extracting cyanotoxin. Further improvement of extraction can be tailored by using a specific organoclay complex that has some similarity in the chemical structure between the pre-adsorbed organic cation to the clay mineral and the chemical structure of cyanotoxin.
文摘Adsorption of phenthoate and acetochlor onto kaolin, montmorillonite, bentonite clays and respective organoclays prepared by the exchange of quaternary ammonium as tetradecyltrimethyl ammonium bromide(TTAB), dodecyltrimethylammonium bromide(DTAB), and cetylpyridinium chloride(CPC) were studied. The adsorption equilibrium data points were fitted to Freundlich isotherm equations. The adsorption of phenthoate and acetochlor were significantly enhanced by surfactant treatment of the clays. The amount of both pesticides adsorbed per unit mass of organoclay followed the order of TTA-kaolin < TTA-montmorillonite < TTA-bentonite, which is inconsistent with the organic carbon content of the clays. The removal efficiency of organomontmorillonite to treat acetochlor is in the order of CP(C 16 )-montmorillonite > TTA(C 14 )-montmorillonite > DTA(C 12 )-montmorillonite. Phenthoate is adsorbed to greater extent than acetochlor by each adsorbent, which may be due to the higher hydrophobicity of phenthoate, indicating considerable hydrophobic interaction between adsorbent/adsorbate systems.
文摘This work presents a new approach for the fabrication of organic/inorganic nanohybrids as anticancer drugs by an intercalation method using S,S-bis（α,α′-dimethyl-α″-acetic acid） （trithiocarbonate） as a modifier and two organoclays, such as reactive octadecylamine/MMT （montmorillonite） and non-reactive dimethyldidodecyl ammonium/MMT. The chemical and physical structures and the surface morphology of these covalently and non-covalently linked nanohybrids were investigated by FT-IR （Fourier translbrm infrared） spectroscopy, ^13C and ^29Si solid state NMR （nuclear magnetic resonance） spectroscopy, XRD （X-ray powder diffraction） and SEM （scanning electron microscopy） analyses, respectively. To evaluate the anticancer activities of the novel BATC/organoclay hybrids against MCF-7 breast cancer cells, a combination of different biochemical and biophysical testing techniques were used. Cell proliferation and cytotoxicity were detected in vitro using a real-time analysis. Cell death was confirmed by using apoptotic and necrotic analyses, the effects of which were detennined by the double staining and Annexin-V-FLUOS testing method. The results demonstrate that intercalated hybrid complexes containing a combination of various anticancer sites, such as free and complexed carboxyl, trithiocarbonate, amine and ammonium cations significantly induced cell death in breast cancer via their interactions with the DNA macromolecules of cancer cells by destroying the self-assemb｜ed structure of growing cells. Fabricated hybrid complexes may represent a new generation of effective and selective anticancer drug systems with a synthetic/natural origin for cancer chemotherapy.
基金financial supports via MS and PhD bursarsthe Turkish Scientific and Technology Research Council(TUBITAK)for the financial support of this work through project TBAG-HD/249.
文摘Functional copolymer–clay hybrids were synthesized by radical-initiated intercalative copolymerization of maleic acid (MA) and acrylamide (AAm) with 2,2’-azobis (2-methylpropionamidine) dihydrochloride as a water-soluble ionizable radical initiator in the presence of reactive (octadecyl amine (ODA)-MMT) and non-reactive (dimethyldodecyl ammonium (DMDA)-MMT) organoclays at 50oC in aqueous medium under nitrogen atmosphere. The monomers was dissolved in aqueous medium, as well as both used clay particles were easily dissolved and dispersed with partially swollen in deionized water, respectively. Structure, thermal behavior and morphology of the synthesized nanocomposites were investigated by FTIR, XRD, DSC-TGA, SEM and TEM analysis methods, respectively. It was demonstrated that intercalative copolymerization proceed via ion exchange between organoclays and carboxylic groups of monomers/polymers which essentially improved interfacial interaction of polymer matrix and clay layers through strong H-bonding. In case of intercalative copolymerization in the presence of ODA-MMT clay, similar improvement was provided by in situ hydrogen-bonding and amidolysis of carboxylic/anhydride groups from copolymer chains with primary amine group of ODA-MMT. The nanocomposites exhibit higher intercalation/exfoliation degree of copolymer chains, improved thermal properties and fine dispersed morphology.
文摘Ethylene copolymers with different polar comonomers,such as vinyl acetate,methyl acrylate,glycidyl methacrylate,and maleic anhydride,were used for the preparation of polymer/clay nanocomposites by statically annealing their mechanical mixtures with different commercial or home-made organically modified montmorillonites containing only one long alkyl tail.The nanostructure of the products was monitored by X-ray diffraction,and the dispersion of the silicate particles within the polymer matrix was qualitatively evaluated through microscopic analyses.The effect of the preparation conditions on the structure and the morphology of the composites was also addressed through the characterization of selected samples with similar composition prepared by melt compounding.In agreement with the findings reported in a previous paper for the composites filled with two-tailed organoclays,intercalation of the copolymer chains within the tighter galleries of the one-tailed clays occurs easily,independent of the application of a mechanical stress.However,the shear-driven break-up of the intercalated clay particles into smaller platelets(exfoliation)seems more hindered.A collapse of the organoclay interlayer spacing was only observed clearly for a commercial one-tailed organoclay-Cloisite®30B–whereas the same effect was almost negligible for a home-made organoclay with similar structure.
基金supported by the National Key Program for Basic Research of China(No.2001CCA02400)the National Natural Science Foundation of China(Grant No.49672097,49972017 and 40172022).
文摘The investigation of the environmental properties of minerals, i.e., environmental mineralogy, is a branch of science dealing with interactions between natural minerals and spheres of the Earth surface as well as a reflection of global change, prevention of ecological destruction, participation in biomineralogy, and remediation of environmental pollution. Pollutant treatment by natural minerals is based on the natural law and reflects natural self-purification functions in the inorganic world, similar to that of the organic world - a biological treatment. A series of case studies related to natural self-purification, which were mostly completed by our group, are discussed in this paper. In natural cryptomelane there is a larger pseudotetragonal tunnel than that formed by [MnO6] octahedral double chains, with an aperture of 0.462-0.466 nm2, filled with K cations. Cryptomelane might be a real naturally-occurring mineral of the active octahedral molecular sieve (OMS-2). CrⅥ-bearing wastewater can be treated by natural pyrrhotite, which is used as a reductant to reduce CrⅥ and as a precipitant to precipitate CrⅢ simultaneously. Batch experiments were conducted using the CTMAB-Montmorillonite as an adsorbent for aromatic contaminants (phenol, aniline, benzene, toluene and xylenes), which are detected frequently in the leaching water from municipal waste deposits around China. The CTMAB modification has proved very effective to enhance the adsorption capacity of the sorbent. Expansion of vermiculite develops loose interior structures, such as pores or cracks, inside briquettes, and thus brings enough oxygen for combustion and the sulfation reaction. Effective combustion of the original carbon reduces the amount of dust in the fly ash.
