Platinum–cobalt(Pt–Co) alloy electrocatalysts were prepared on pretreated carbon cloth by electrodeposition from different plating baths with the aim of finding suitable plating bath conditions that could control th...Platinum–cobalt(Pt–Co) alloy electrocatalysts were prepared on pretreated carbon cloth by electrodeposition from different plating baths with the aim of finding suitable plating bath conditions that could control the chemical composition of the Pt–Co alloy electrodeposits over a wide range(from 0 to 100 at% Pt) and then to study the relationship of the deposit composition on the oxygen reduction reaction(ORR) electroactivity. The type of supporting electrolyte, the solution pH, Pt and Co concentrations of the plating bath and the current density used for electrodeposition all play a crucial role in the composition of the electrodeposited Pt–Co alloy. Pt contents in all the Pt–Co alloys deposited in H_2SO_4 are at a relatively high and narrow level(83 at%–97 at% Pt), regardless of the electrodeposition conditions used. While the Pt contents in the Pt–Co alloys deposited in Na_2SO_4 could reach a very low and broad level(5 at%–97 at% Pt), evidence of Co oxide formation is observed. Of the three supporting electrolytes studied, only NaCl effectively produces Pt–Co deposits over a wide range of compositions(8–90 at% Pt)by controlling the Pt and Co concentrations of the plating bath and using the high enough current density. The results show a qualitative correlation between Pt–Co deposit composition and ORR activity, where Pt–Co alloy catalysts with ≥ 45 at% Pt tend to yield higher ORR activities than the pure Pt catalyst, with the best ORR performance obtained from the Pt–Co alloy catalyst with 78 at% Pt.展开更多
Objective:To conduct a systemic evaluation of the medicinal value of seeds which include macroscopic and microscopic characterization,physiochomical evaluation,preliminary phylochemical screening and experimental anti...Objective:To conduct a systemic evaluation of the medicinal value of seeds which include macroscopic and microscopic characterization,physiochomical evaluation,preliminary phylochemical screening and experimental antipyretic activity.Methods:Saraca asoca seed was studied for pharmacognostical,phytochemical and other recommended methods for standardizations.Also,the acetone extract of the seeds was evaluated for acute toxicity study and antipyretic activity using Brewer's yeast induced pyrexia in Wislar rats at oral doses of 300 mg/kg and 500 mg/kg.Results:After phytochemical screening,the acetone extract showed the presence of saponin,tannins and flavonoids which inhibit pyrexia.The therapeutic efficacy achieved at both the dose levels of the research drug and standard drug aspirin(100 mg/kg)showed significant(P<0.01)antipyretic activity when compared to the control group.The highly significant antipyretic effect exhibited at the dose of 500 mg/kg was also found to be sustainable in nature.Conclusions:The antipyretic effect of the acetone extract showed significant results in rats at the dose of 500 mg/kg after following the standard pharmacognostical and phylochemieal met hods.展开更多
Two triterpenoid saponins, 6, 7, together with five known compounds were isolated from the roots of Arachis hypogea L. collected in Vietnam. Their structures were established by spectroscopic analysis (1D, 2D NMR and ...Two triterpenoid saponins, 6, 7, together with five known compounds were isolated from the roots of Arachis hypogea L. collected in Vietnam. Their structures were established by spectroscopic analysis (1D, 2D NMR and HRMS) as well as by comparison with those reported in the literature. Furthermore, the high content of resveratrol in the roots opens a new potential resource for pharmaceutical companies to prepare medicines from the wasted peanut roots.展开更多
This study aims to remove the metals(inorganic and heavy metals) in waste foundry sand(WFS)via chemical washing method. Washed waste foundry sand(WWFS) samples were obtained by using triptych washing successively with...This study aims to remove the metals(inorganic and heavy metals) in waste foundry sand(WFS)via chemical washing method. Washed waste foundry sand(WWFS) samples were obtained by using triptych washing successively with 5 M HCl, 5 M H_2SO_4 and 5 M NaOH solutions. Analysis on functional groups,micropores, heavy metals,and inorganic components of WFS and WWFS was carried out by using FT-IR, SEM and XRF. Results show that the concentration values of some inorganic components such as Ca, Fe, Mg, S were decreased, and the maximum removal percentage of these inorganic components are 47%, 19%, 32%, and 8%,respectively. The concentration values for each of the heavy metals of WWFS are below of limit values given in App-3 List of Regulation on General Principles of Waste Management. The removal percentages of Pb, As and Zn elements are 100%, 71%, and 40%, respectively. The findings of this research suggest that WWFS can be used in more applications due to its ability to remove heavy metals and some other inorganic components.展开更多
Anaerobic digestion is often used as an approach to deal with high COD waste streams. Compared to the aeration systems it allows better energy management due to the biogas production but also has several limitations i...Anaerobic digestion is often used as an approach to deal with high COD waste streams. Compared to the aeration systems it allows better energy management due to the biogas production but also has several limitations including inlet waste streams quality and the additional equipment required for energy harvesting. In recent years, the bio-electrochemical systems (BES) and processes are intensively studied as a method for organic waste utilization, including wastewater. They potentially could bring several benefits to the wastewater treatment, mainly due to avoiding aeration (and aeration cost) and direct energy recovering in the form of electricity. Besides their anaerobic nature, the biological processes in BES are respiration-like contrary to the fermentative degradation typical for conventional anaerobic digestion which eventually will provide better mineralization and higher efficiency in terms of COD and BOD removal in such reactors. This study is a direct comparison between conventional anaerobic digestion and Microbial Fuel Cell (as a typical BES reactor) during utilization of wastewater from industrial production of ethanol by fermentation. COD removal rates and dynamics, energy recovery properties and parameters such as secondary sludge production are investigated in order to characterize the feasibility and technological readiness of BES as a step towards their commercialization.展开更多
The possibility of the increase in open-circuit voltage of organic photovoltaic cells based primarily indium-tin oxide (ITO)/rubrene/fullerene/Al structure by changing the work function of ITO anodes and Al cathodes w...The possibility of the increase in open-circuit voltage of organic photovoltaic cells based primarily indium-tin oxide (ITO)/rubrene/fullerene/Al structure by changing the work function of ITO anodes and Al cathodes was described in this work. To change built-in potential preferably in order to increase the open-circuit voltage, the work function of ITO should be increased and work function of Al should be decreased. The correlation between the change in work functions of electrodes and performance of the organic photovoltaic cells before and after surface modifications was examined in detail. The enhancement of open-circuit voltage depends on a function of work function change of both ITO and Al electrode. We could show that the built-in potential in the cells played an important role in open-circuit voltage.展开更多
In this present work, ultrafiltration was applied for the purification of agro waste Greek red saffron. The agro waste saffron (before and after ultrafiltration) was used for the preparation of oil- in-water emulsions...In this present work, ultrafiltration was applied for the purification of agro waste Greek red saffron. The agro waste saffron (before and after ultrafiltration) was used for the preparation of oil- in-water emulsions. Produced emulsions were examined for their viscosity, pH and conductivity during time. Also surface tension values of the aqueous and oily phase of the emulsions were measured. Saffron is known for its antioxidant and anti-solar properties. Anti-solar activity of saffron was evaluated by measuring the SPF value of the emulsion. UV-Vis measurements have shown an incredible increase of the absorption of saffron after ultrafiltration. The emulsions made with the purified saffron presented a better anti-solar activity and at the same time remarkably improvement of their antioxidant and antiaging properties giving a very promising alternative to the cosmetic industry.展开更多
The selection of carbon sources and the biosynthesis of polyhydroxybutyrate(PHB)by the Azotobacter vinelandii N-15 strain using renewable raw materials were investigated.Among the tested substrates(starch,sucrose,mola...The selection of carbon sources and the biosynthesis of polyhydroxybutyrate(PHB)by the Azotobacter vinelandii N-15 strain using renewable raw materials were investigated.Among the tested substrates(starch,sucrose,molasses,bran),molasses as the carbon source yielded the highest PHB production.The maximum polymer yield(26%of dry biomass)was achieved at a molasses concentration of 40 g/L.PHB formation was confirmed via thinlayer chromatography,gas chromatography and Fourier transform infrared spectroscopy.Composite films based on PHB,polylactic acid(PLA),and their blends were fabricated using the solvent casting.The biodegradation of these films was studied with bacteria isolated from plastic-contaminated soil.These bacteria utilized the biopolymers as their sole carbon source,with the biodegradation process lasting three months.Structural and chemical changes in the films were analyzed using FTIR spectroscopy,differential scanning calorimetry,and thermogravimetry.Among the microorganisms used to study the biodegradation of PHB,PLA,and their blends,Streptomyces sp.K2 and Streptomyces sp.K4 exhibited the highest biodegradation efficiency.PHB-containing films demonstrated significant advantages over other biodegradable polymers,as they degrade under aerobic conditions via enzymatic hydrolysis using microbial depolymerases.展开更多
Photocatalysis is widely regarded as a highly promising sustainable technique for addressing the challenges posed by environmental pollution and energy provision.In recent years,metal-loaded MOFs has become a rising s...Photocatalysis is widely regarded as a highly promising sustainable technique for addressing the challenges posed by environmental pollution and energy provision.In recent years,metal-loaded MOFs has become a rising star within the domain of photocatalysis due to its high specific surface area and porosity,adjustable structure,diverse and abundant catalytic components,which has exhibited excellent photocatalytic activity and exhibit great potential in a range of disciplines.In this paper,the principles for evaluating the photocatalytic performance of MOFs-based materials were firstly introduced,and some typical examples were also listed accordingly.Along with this,particular emphasis is paid to the main factors affecting the photocatalytic performance of metal-loaded MOFs.Then the synthesis and design strategies of MOFs loaded metal entities of varying sizes(single atoms,nanoclusters,and nanoparticles),and their applications in photocatalytic CO_(2)reduction,hydrogen production,photooxidation and photocatalytic hydrogenation were summarized and discussed.Finally,the opportunities and challenges faced in this kind of MOFs-based composites were analyzed from different perspectives.This report is expected to help researchers design and develop high-performance MOFs-based photocatalytic materials.展开更多
Nowadays,the development of effective bioplastics aims to combine traditional plastics’functionality with environmentally friendly properties.The most effective and durable modern bioplastics are made from the edible...Nowadays,the development of effective bioplastics aims to combine traditional plastics’functionality with environmentally friendly properties.The most effective and durable modern bioplastics are made from the edible part of crops.This forces bioplastics to competewith food production because the crops that produce bioplastics can also be used for human nutrition.That is why the article’s main focus is on creating bioplastics using renewable,non-food raw materials(cellulose,lignin,etc.).Eco-friendly composites based on a renewable bioplastic blend of polybutylene adipate-co-terephthalate,corn starch,and poly(lactic acid)with reed and hemp waste as a filler.The physic-chemical features of the structure and surface,as well as the technological characteristics of reed and hemp waste as the organic fillers for renewable bioplastic blend of polybutylene adipate-co-terephthalate,corn starch,and poly(lactic acid),were studied.Theeffect of the fractional composition analysis,morphology,and nature of reed and hempwaste on the quality of the design of eco-friendly biodegradable composites and their ability to disperse in the matrix of renewable bioplastic blend of polybutylene adipate-co-terephthalate,corn starch and poly(lactic acid)was carried out.The influence of different content and morphology of reed and hemp waste on the composite characteristics was investigated.It is shown that the most optimal direction for obtaining strong eco-friendly biodegradable composites based on a renewable bioplastic blend of polybutylene adipate-co-terephthalate,corn starch,and poly(lactic acid)is associated with the use of waste reed stalks,with its optimal content at the level of 50 wt.%.展开更多
Oxalic acid was found to be an efficient catalyst for Pechmann condensation, which includes the reaction between phenols and β-keto esters leading to formation of coumarin derivatives. The advantages of present metho...Oxalic acid was found to be an efficient catalyst for Pechmann condensation, which includes the reaction between phenols and β-keto esters leading to formation of coumarin derivatives. The advantages of present methods are the use of cheap and easy available catalyst, solvent-free reaction conditions, better yields and shorter reaction time.展开更多
A novel series of 5-（（5-substituted-1H-1,2,4-triazol-3-yl）methyl）-4,5,6,7-tetrahydrothieno[3,2-c]pyr- idines 5（a-i） has been synthesized from thienopyridine hydrazide, substituted aromatic nitriles using 4- dime...A novel series of 5-（（5-substituted-1H-1,2,4-triazol-3-yl）methyl）-4,5,6,7-tetrahydrothieno[3,2-c]pyr- idines 5（a-i） has been synthesized from thienopyridine hydrazide, substituted aromatic nitriles using 4- dimethylaminopyridine （DMAP） as a catalyst under microwave irradiation and evaluated for their in vitro antifungal activity. Compound 5g is found to be more potent against Candida albicans when compared with miconazole. Docking study of the newly synthesized compounds was performed, and results showed good binding mode in the active site of fungal enzyme P450 cytochrome lanosterol 14α- demethylase. ADMET properties of synthesized compounds were also analyzed and showed good drug like properties. The results of in vitro antifungal activity, docking study and ADMET prediction revealed that the synthesized compounds have potential antifungal activity and can be further optimized and developed as a lead compound.展开更多
Ceria(CeO2)supports,synthesized by hydrothermal treatment with different synthesis time(CeO2-X h,where X is the synthesis time in h)in the presence of the surfactant cetyltrimethyl ammonium bromide,were used as suppor...Ceria(CeO2)supports,synthesized by hydrothermal treatment with different synthesis time(CeO2-X h,where X is the synthesis time in h)in the presence of the surfactant cetyltrimethyl ammonium bromide,were used as supports for gold(Au)catalysts.The synthesis time significantly affects the morphological structure and crystallite size of CeO2,where CeO2-2 h has the smallest crystallite size with coexisting nanorods and nanoparticles.Transmission electron microscopy analysis confirms the morphology of CeO2 with distinctive(110),(100)and(111)planes,in agreement with interplanar spacings of 0.19,0,27 and 0.31,respectively.However,the morphology of CeO2-8 h and CeO2-48 h is mainly a truncated octahedral with crystal planes(111)and(100)accompanied by an interplanar spacing of 0.31 and0.27 nm,respectively.The CeO2-X h supports and those with a 3 wt%Au loading(Au/CeO2-X h)were investigated in the oxidative steam reforming of methanol at temperatures between 200 and 400℃.The Au/CeO2-2 h gave the highest methanol conversion level and hydrogen yield at a low temperature of 250℃.This superior catalytic performance results from the good interaction between the metal and support and the well-distributed Au species on the CeO2 support.展开更多
A simple, rapid, and reproducible method is described employing solid phase extraction(SPE) using dichloromethane followed by gas chromatography(GC) with flame ionization detection(FID) for determination of volatile ...A simple, rapid, and reproducible method is described employing solid phase extraction(SPE) using dichloromethane followed by gas chromatography(GC) with flame ionization detection(FID) for determination of volatile organic compound(VOC) from the Buriganga River water of Bangladesh. The method was applied to detect the benzene, toluene, ethylbenzene, xylene and cumene(BTEXC) in the sample collected from the surface or 15 cm depth of water. Two hundred ml of n hexane pretreated and filtered water samples were applied directly to a C 18 SPE column. BTEXC were extracted with dichloromethane and average concentrations were obtained as 0 104 to 0 372 μg/ml. The highest concentration of benzene was found as 0 372 μg/ml with a relative standard deviation(RSD) of 6 2%, and cumene was not detected. Factors influencing SPE e.g., adsorbent types, sample load volume, eluting solvent, headspace and temperatures, were investigated. A cartridge containing a C 18 adsorbent and using dichloromethane gave better performance for extraction of BTEXC from water. Average recoveries exceeding 90% could be achieved for cumene at 4℃ with a 2 7% RSD.展开更多
The activity and thermal stability of Pd/Al2O3 and Pd/（Al2O3＋MOx） （M=Ca, La, Ce） palladium catalysts in the reaction of complete oxidation of methane are presented in this study. The catalyst supports were prepar...The activity and thermal stability of Pd/Al2O3 and Pd/（Al2O3＋MOx） （M=Ca, La, Ce） palladium catalysts in the reaction of complete oxidation of methane are presented in this study. The catalyst supports were prepared by sol-gel method and they were dried either conventionally or with supercritical carbon dioxide. Then they were impregnated with palladium nitrate solution. The catalysts with unmodified alumina had a high surface area. The activity and thermal stability of the aluminasupported catalyst was also very high. The introduction of calcium, lanthanum, or cerium oxide into alumina support caused a decrease of the surface area in the way dependent on the support precursor drying method. These modifiers decreased the activity of palladium catalysts, and they required higher temperatures for the complete oxidation of methane than unmodified Pd/Al2O3. The improvement of the palladium activity by lanthanum and cerium support modifier was observed only at low temperatures of the reaction.展开更多
A simple one-pot synthetic method for the preparation of 2,4,5-triaryl-lH-imidazoles from benzoin or benzil, ammonium acetate, aromatic aldehydes, and ZrOCl2-8H2O catalyst is described. The ZrOCl2-8H2O catalyst was fo...A simple one-pot synthetic method for the preparation of 2,4,5-triaryl-lH-imidazoles from benzoin or benzil, ammonium acetate, aromatic aldehydes, and ZrOCl2-8H2O catalyst is described. The ZrOCl2-8H2O catalyst was found to be equally effective for aromatic and heteroaromatic aldehydes and also for the preparation of substituted 1,4-di（4,5-diphenylimidazol-yl） benzene.展开更多
The aim of the present investigation was to demonstrate an approach involving use of liquid chromatography(LC) and liquid chromatography-mass spectrometry(LC–MS) to separate, identify and characterize very small quan...The aim of the present investigation was to demonstrate an approach involving use of liquid chromatography(LC) and liquid chromatography-mass spectrometry(LC–MS) to separate, identify and characterize very small quantities of degradation products(DPs) of acebutolol without their isolation from the reaction mixtures. The drug was subjected to oxidative, hydrolytic, thermal and photolytic stress conditions as per International Conference on Harmonization(ICH) guideline Q1 A(R2). Among all the stress conditions the drug was found to be labile in hydrolytic(acidic & basic) and photolytic stress conditions, while it was stable in water-induced hydrolysis, oxidative and thermal stress conditions. A total of four degradation products were formed. A C18 column was employed for the separation of all the DPs on a gradient mode by using high-performance liquid chromatography(HPLC). All the DPs were characterized with the help of their fragmentation pattern and the masses obtained upon LC–MS/MS and MSnanalysis. All the hitherto unknown degradation products were identified as 1-(2-(2-hydroxy-3-(isopropylamino)propoxy)-5-(amino)phenyl)ethanone(DP-I), N-(4-(2-hydroxy-3-(isopropylamino)propoxy)-3-acetylphenyl)acrylamide(DP-II), 1-(2-(2-hydroxy-3-(isopropylamino)propoxy)-5-(hydroxymethylamino)phenyl)ethanone(DP-III) and 1-(6-(2-hydroxy-3-(isopropylamino)propoxy)-2,3-dihydro-2-propylbenzo[d]oxazol-5-yl)ethanone(DP-IV). Finally the in-silico carcinogenicity and hepatotoxicity predictions of the drug and all the DPs were performed by using toxicity prediction softwares viz., TOPKAT, LAZAR and Discovery Studio ADMET. The results of in-silico toxicity studies revealed that acebutolol(0.967) and DP-I(0.986) were found to be carcinogenic, while acebutolol(0.490) and DP-IV(0.437) were found to be hepatotoxic.展开更多
Synthesised triphenylphosphine-linked multiwalled carbon nanotubes （Tpp-MWCNTs） were used to study the adsorption of nickel in aqueous solutions and their adsorption capabilities were compared with purified MWCNTs.T...Synthesised triphenylphosphine-linked multiwalled carbon nanotubes （Tpp-MWCNTs） were used to study the adsorption of nickel in aqueous solutions and their adsorption capabilities were compared with purified MWCNTs.The adsorption capacity increased with an increase in pH for all adsorbents.The adsorption equilibrium was reached in 40 and 30 min for purified MWCNTs and Tpp-MWCNTs,respectively.Both Freundlich and Langmuir isotherms used to investigate the adsorption process fitted the experimental data well with the correlation coefficient R 2 close to 1 for all adsorbents.On the other hand,the experimental data fitted well with a pseudo secondorder model.The speciation of nickel also influenced the adsorption on the purified and Tpp-MWCNTs.The adsorbents used in this study showed superior adsorption capacity when compared to other adsorbents reported in the literature.展开更多
Differently substituted benzimidazoles have been synthesized in very good yields in solvent-free conditions from o-phenylenediamine and aldehydes in the presence of BF3·OEt2 as a catalyst. The method is applicabl...Differently substituted benzimidazoles have been synthesized in very good yields in solvent-free conditions from o-phenylenediamine and aldehydes in the presence of BF3·OEt2 as a catalyst. The method is applicable to aromatic, unsaturated and aliphatic aldehydes and to substituted o-phenylenediamines without significant differences.展开更多
At present, the use of rare earth elements（REEs） has become an inevitable necessity in many modern industries. In general, liquid extraction is the best commercial method for extracting REEs due to its ability to co...At present, the use of rare earth elements（REEs） has become an inevitable necessity in many modern industries. In general, liquid extraction is the best commercial method for extracting REEs due to its ability to control high volumes of liquids with electrical load. With the aim of improving a separation technology that would be superior to the existing extraction systems, the extraction behaviors of La（Ⅲ）,Pr（Ⅲ）, and Nd（Ⅲ） from an HCI medium with Cyanex 272 in the presence of the complexing agent lactic acid（HLac） and auxiliary agents citric acid（H3 Cit）, acetic acid（HAc）, and Titriplex Ⅲ have been reported.The effect of pH and lactic acid concentration has been examined. The use of lactic acid as a complexing agent leading to a high extraction of REEs with Cyanex 272 at pH = 5 was compared with systems without lactic acid. The results show that the use of acetic acid along with lactic acid leads to an increase in the extraction percentage of LREEs. While use of citric acid and Titriplex Ⅲ reduces the extraction percentage of LREEs. Finally, the presence of Titriplex Ⅲ together with lactic acid could lead to an increase in the separation factor of Pr and Nd.展开更多
基金financially supported by the Ratchadapisek Sompoch Endowment Fund, Chulalongkorn University (Sci-Super 2014-026)the Thailand Research Fund (TRF IRG5780001)the Faculty of Science, Chulalongkorn University
文摘Platinum–cobalt(Pt–Co) alloy electrocatalysts were prepared on pretreated carbon cloth by electrodeposition from different plating baths with the aim of finding suitable plating bath conditions that could control the chemical composition of the Pt–Co alloy electrodeposits over a wide range(from 0 to 100 at% Pt) and then to study the relationship of the deposit composition on the oxygen reduction reaction(ORR) electroactivity. The type of supporting electrolyte, the solution pH, Pt and Co concentrations of the plating bath and the current density used for electrodeposition all play a crucial role in the composition of the electrodeposited Pt–Co alloy. Pt contents in all the Pt–Co alloys deposited in H_2SO_4 are at a relatively high and narrow level(83 at%–97 at% Pt), regardless of the electrodeposition conditions used. While the Pt contents in the Pt–Co alloys deposited in Na_2SO_4 could reach a very low and broad level(5 at%–97 at% Pt), evidence of Co oxide formation is observed. Of the three supporting electrolytes studied, only NaCl effectively produces Pt–Co deposits over a wide range of compositions(8–90 at% Pt)by controlling the Pt and Co concentrations of the plating bath and using the high enough current density. The results show a qualitative correlation between Pt–Co deposit composition and ORR activity, where Pt–Co alloy catalysts with ≥ 45 at% Pt tend to yield higher ORR activities than the pure Pt catalyst, with the best ORR performance obtained from the Pt–Co alloy catalyst with 78 at% Pt.
基金Supported by University Grants Commission.New Delhi[Grantsanctioned vide no-F.No.37-496/2009(SR)]
文摘Objective:To conduct a systemic evaluation of the medicinal value of seeds which include macroscopic and microscopic characterization,physiochomical evaluation,preliminary phylochemical screening and experimental antipyretic activity.Methods:Saraca asoca seed was studied for pharmacognostical,phytochemical and other recommended methods for standardizations.Also,the acetone extract of the seeds was evaluated for acute toxicity study and antipyretic activity using Brewer's yeast induced pyrexia in Wislar rats at oral doses of 300 mg/kg and 500 mg/kg.Results:After phytochemical screening,the acetone extract showed the presence of saponin,tannins and flavonoids which inhibit pyrexia.The therapeutic efficacy achieved at both the dose levels of the research drug and standard drug aspirin(100 mg/kg)showed significant(P<0.01)antipyretic activity when compared to the control group.The highly significant antipyretic effect exhibited at the dose of 500 mg/kg was also found to be sustainable in nature.Conclusions:The antipyretic effect of the acetone extract showed significant results in rats at the dose of 500 mg/kg after following the standard pharmacognostical and phylochemieal met hods.
文摘Two triterpenoid saponins, 6, 7, together with five known compounds were isolated from the roots of Arachis hypogea L. collected in Vietnam. Their structures were established by spectroscopic analysis (1D, 2D NMR and HRMS) as well as by comparison with those reported in the literature. Furthermore, the high content of resveratrol in the roots opens a new potential resource for pharmaceutical companies to prepare medicines from the wasted peanut roots.
文摘This study aims to remove the metals(inorganic and heavy metals) in waste foundry sand(WFS)via chemical washing method. Washed waste foundry sand(WWFS) samples were obtained by using triptych washing successively with 5 M HCl, 5 M H_2SO_4 and 5 M NaOH solutions. Analysis on functional groups,micropores, heavy metals,and inorganic components of WFS and WWFS was carried out by using FT-IR, SEM and XRF. Results show that the concentration values of some inorganic components such as Ca, Fe, Mg, S were decreased, and the maximum removal percentage of these inorganic components are 47%, 19%, 32%, and 8%,respectively. The concentration values for each of the heavy metals of WWFS are below of limit values given in App-3 List of Regulation on General Principles of Waste Management. The removal percentages of Pb, As and Zn elements are 100%, 71%, and 40%, respectively. The findings of this research suggest that WWFS can be used in more applications due to its ability to remove heavy metals and some other inorganic components.
文摘Anaerobic digestion is often used as an approach to deal with high COD waste streams. Compared to the aeration systems it allows better energy management due to the biogas production but also has several limitations including inlet waste streams quality and the additional equipment required for energy harvesting. In recent years, the bio-electrochemical systems (BES) and processes are intensively studied as a method for organic waste utilization, including wastewater. They potentially could bring several benefits to the wastewater treatment, mainly due to avoiding aeration (and aeration cost) and direct energy recovering in the form of electricity. Besides their anaerobic nature, the biological processes in BES are respiration-like contrary to the fermentative degradation typical for conventional anaerobic digestion which eventually will provide better mineralization and higher efficiency in terms of COD and BOD removal in such reactors. This study is a direct comparison between conventional anaerobic digestion and Microbial Fuel Cell (as a typical BES reactor) during utilization of wastewater from industrial production of ethanol by fermentation. COD removal rates and dynamics, energy recovery properties and parameters such as secondary sludge production are investigated in order to characterize the feasibility and technological readiness of BES as a step towards their commercialization.
文摘The possibility of the increase in open-circuit voltage of organic photovoltaic cells based primarily indium-tin oxide (ITO)/rubrene/fullerene/Al structure by changing the work function of ITO anodes and Al cathodes was described in this work. To change built-in potential preferably in order to increase the open-circuit voltage, the work function of ITO should be increased and work function of Al should be decreased. The correlation between the change in work functions of electrodes and performance of the organic photovoltaic cells before and after surface modifications was examined in detail. The enhancement of open-circuit voltage depends on a function of work function change of both ITO and Al electrode. We could show that the built-in potential in the cells played an important role in open-circuit voltage.
文摘In this present work, ultrafiltration was applied for the purification of agro waste Greek red saffron. The agro waste saffron (before and after ultrafiltration) was used for the preparation of oil- in-water emulsions. Produced emulsions were examined for their viscosity, pH and conductivity during time. Also surface tension values of the aqueous and oily phase of the emulsions were measured. Saffron is known for its antioxidant and anti-solar properties. Anti-solar activity of saffron was evaluated by measuring the SPF value of the emulsion. UV-Vis measurements have shown an incredible increase of the absorption of saffron after ultrafiltration. The emulsions made with the purified saffron presented a better anti-solar activity and at the same time remarkably improvement of their antioxidant and antiaging properties giving a very promising alternative to the cosmetic industry.
基金financial support of this paper by the Ministry of Education and Science of Ukraine under grant(Biotherm/0124U000789).
文摘The selection of carbon sources and the biosynthesis of polyhydroxybutyrate(PHB)by the Azotobacter vinelandii N-15 strain using renewable raw materials were investigated.Among the tested substrates(starch,sucrose,molasses,bran),molasses as the carbon source yielded the highest PHB production.The maximum polymer yield(26%of dry biomass)was achieved at a molasses concentration of 40 g/L.PHB formation was confirmed via thinlayer chromatography,gas chromatography and Fourier transform infrared spectroscopy.Composite films based on PHB,polylactic acid(PLA),and their blends were fabricated using the solvent casting.The biodegradation of these films was studied with bacteria isolated from plastic-contaminated soil.These bacteria utilized the biopolymers as their sole carbon source,with the biodegradation process lasting three months.Structural and chemical changes in the films were analyzed using FTIR spectroscopy,differential scanning calorimetry,and thermogravimetry.Among the microorganisms used to study the biodegradation of PHB,PLA,and their blends,Streptomyces sp.K2 and Streptomyces sp.K4 exhibited the highest biodegradation efficiency.PHB-containing films demonstrated significant advantages over other biodegradable polymers,as they degrade under aerobic conditions via enzymatic hydrolysis using microbial depolymerases.
基金supported by the Beijing Natural Science Foundation(No.L233011)Guangdong Province Natural Science Foundation(No.2022A1515011918)USTB Research Center for International People-to-People Exchange in Science.Technology and Civilization(No.2023KFYB003)。
文摘Photocatalysis is widely regarded as a highly promising sustainable technique for addressing the challenges posed by environmental pollution and energy provision.In recent years,metal-loaded MOFs has become a rising star within the domain of photocatalysis due to its high specific surface area and porosity,adjustable structure,diverse and abundant catalytic components,which has exhibited excellent photocatalytic activity and exhibit great potential in a range of disciplines.In this paper,the principles for evaluating the photocatalytic performance of MOFs-based materials were firstly introduced,and some typical examples were also listed accordingly.Along with this,particular emphasis is paid to the main factors affecting the photocatalytic performance of metal-loaded MOFs.Then the synthesis and design strategies of MOFs loaded metal entities of varying sizes(single atoms,nanoclusters,and nanoparticles),and their applications in photocatalytic CO_(2)reduction,hydrogen production,photooxidation and photocatalytic hydrogenation were summarized and discussed.Finally,the opportunities and challenges faced in this kind of MOFs-based composites were analyzed from different perspectives.This report is expected to help researchers design and develop high-performance MOFs-based photocatalytic materials.
文摘Nowadays,the development of effective bioplastics aims to combine traditional plastics’functionality with environmentally friendly properties.The most effective and durable modern bioplastics are made from the edible part of crops.This forces bioplastics to competewith food production because the crops that produce bioplastics can also be used for human nutrition.That is why the article’s main focus is on creating bioplastics using renewable,non-food raw materials(cellulose,lignin,etc.).Eco-friendly composites based on a renewable bioplastic blend of polybutylene adipate-co-terephthalate,corn starch,and poly(lactic acid)with reed and hemp waste as a filler.The physic-chemical features of the structure and surface,as well as the technological characteristics of reed and hemp waste as the organic fillers for renewable bioplastic blend of polybutylene adipate-co-terephthalate,corn starch,and poly(lactic acid),were studied.Theeffect of the fractional composition analysis,morphology,and nature of reed and hempwaste on the quality of the design of eco-friendly biodegradable composites and their ability to disperse in the matrix of renewable bioplastic blend of polybutylene adipate-co-terephthalate,corn starch and poly(lactic acid)was carried out.The influence of different content and morphology of reed and hemp waste on the composite characteristics was investigated.It is shown that the most optimal direction for obtaining strong eco-friendly biodegradable composites based on a renewable bioplastic blend of polybutylene adipate-co-terephthalate,corn starch,and poly(lactic acid)is associated with the use of waste reed stalks,with its optimal content at the level of 50 wt.%.
文摘Oxalic acid was found to be an efficient catalyst for Pechmann condensation, which includes the reaction between phenols and β-keto esters leading to formation of coumarin derivatives. The advantages of present methods are the use of cheap and easy available catalyst, solvent-free reaction conditions, better yields and shorter reaction time.
文摘A novel series of 5-（（5-substituted-1H-1,2,4-triazol-3-yl）methyl）-4,5,6,7-tetrahydrothieno[3,2-c]pyr- idines 5（a-i） has been synthesized from thienopyridine hydrazide, substituted aromatic nitriles using 4- dimethylaminopyridine （DMAP） as a catalyst under microwave irradiation and evaluated for their in vitro antifungal activity. Compound 5g is found to be more potent against Candida albicans when compared with miconazole. Docking study of the newly synthesized compounds was performed, and results showed good binding mode in the active site of fungal enzyme P450 cytochrome lanosterol 14α- demethylase. ADMET properties of synthesized compounds were also analyzed and showed good drug like properties. The results of in vitro antifungal activity, docking study and ADMET prediction revealed that the synthesized compounds have potential antifungal activity and can be further optimized and developed as a lead compound.
基金Project supported by the Ratchadaphiseksomphot Endowment Fund,Chulalongkorn University(CU-GES-60-04-63-03)the Thammasat University Research Fund under the Research University Network Initiative(8/2560)
文摘Ceria(CeO2)supports,synthesized by hydrothermal treatment with different synthesis time(CeO2-X h,where X is the synthesis time in h)in the presence of the surfactant cetyltrimethyl ammonium bromide,were used as supports for gold(Au)catalysts.The synthesis time significantly affects the morphological structure and crystallite size of CeO2,where CeO2-2 h has the smallest crystallite size with coexisting nanorods and nanoparticles.Transmission electron microscopy analysis confirms the morphology of CeO2 with distinctive(110),(100)and(111)planes,in agreement with interplanar spacings of 0.19,0,27 and 0.31,respectively.However,the morphology of CeO2-8 h and CeO2-48 h is mainly a truncated octahedral with crystal planes(111)and(100)accompanied by an interplanar spacing of 0.31 and0.27 nm,respectively.The CeO2-X h supports and those with a 3 wt%Au loading(Au/CeO2-X h)were investigated in the oxidative steam reforming of methanol at temperatures between 200 and 400℃.The Au/CeO2-2 h gave the highest methanol conversion level and hydrogen yield at a low temperature of 250℃.This superior catalytic performance results from the good interaction between the metal and support and the well-distributed Au species on the CeO2 support.
文摘A simple, rapid, and reproducible method is described employing solid phase extraction(SPE) using dichloromethane followed by gas chromatography(GC) with flame ionization detection(FID) for determination of volatile organic compound(VOC) from the Buriganga River water of Bangladesh. The method was applied to detect the benzene, toluene, ethylbenzene, xylene and cumene(BTEXC) in the sample collected from the surface or 15 cm depth of water. Two hundred ml of n hexane pretreated and filtered water samples were applied directly to a C 18 SPE column. BTEXC were extracted with dichloromethane and average concentrations were obtained as 0 104 to 0 372 μg/ml. The highest concentration of benzene was found as 0 372 μg/ml with a relative standard deviation(RSD) of 6 2%, and cumene was not detected. Factors influencing SPE e.g., adsorbent types, sample load volume, eluting solvent, headspace and temperatures, were investigated. A cartridge containing a C 18 adsorbent and using dichloromethane gave better performance for extraction of BTEXC from water. Average recoveries exceeding 90% could be achieved for cumene at 4℃ with a 2 7% RSD.
文摘The activity and thermal stability of Pd/Al2O3 and Pd/（Al2O3＋MOx） （M=Ca, La, Ce） palladium catalysts in the reaction of complete oxidation of methane are presented in this study. The catalyst supports were prepared by sol-gel method and they were dried either conventionally or with supercritical carbon dioxide. Then they were impregnated with palladium nitrate solution. The catalysts with unmodified alumina had a high surface area. The activity and thermal stability of the aluminasupported catalyst was also very high. The introduction of calcium, lanthanum, or cerium oxide into alumina support caused a decrease of the surface area in the way dependent on the support precursor drying method. These modifiers decreased the activity of palladium catalysts, and they required higher temperatures for the complete oxidation of methane than unmodified Pd/Al2O3. The improvement of the palladium activity by lanthanum and cerium support modifier was observed only at low temperatures of the reaction.
文摘A simple one-pot synthetic method for the preparation of 2,4,5-triaryl-lH-imidazoles from benzoin or benzil, ammonium acetate, aromatic aldehydes, and ZrOCl2-8H2O catalyst is described. The ZrOCl2-8H2O catalyst was found to be equally effective for aromatic and heteroaromatic aldehydes and also for the preparation of substituted 1,4-di（4,5-diphenylimidazol-yl） benzene.
文摘The aim of the present investigation was to demonstrate an approach involving use of liquid chromatography(LC) and liquid chromatography-mass spectrometry(LC–MS) to separate, identify and characterize very small quantities of degradation products(DPs) of acebutolol without their isolation from the reaction mixtures. The drug was subjected to oxidative, hydrolytic, thermal and photolytic stress conditions as per International Conference on Harmonization(ICH) guideline Q1 A(R2). Among all the stress conditions the drug was found to be labile in hydrolytic(acidic & basic) and photolytic stress conditions, while it was stable in water-induced hydrolysis, oxidative and thermal stress conditions. A total of four degradation products were formed. A C18 column was employed for the separation of all the DPs on a gradient mode by using high-performance liquid chromatography(HPLC). All the DPs were characterized with the help of their fragmentation pattern and the masses obtained upon LC–MS/MS and MSnanalysis. All the hitherto unknown degradation products were identified as 1-(2-(2-hydroxy-3-(isopropylamino)propoxy)-5-(amino)phenyl)ethanone(DP-I), N-(4-(2-hydroxy-3-(isopropylamino)propoxy)-3-acetylphenyl)acrylamide(DP-II), 1-(2-(2-hydroxy-3-(isopropylamino)propoxy)-5-(hydroxymethylamino)phenyl)ethanone(DP-III) and 1-(6-(2-hydroxy-3-(isopropylamino)propoxy)-2,3-dihydro-2-propylbenzo[d]oxazol-5-yl)ethanone(DP-IV). Finally the in-silico carcinogenicity and hepatotoxicity predictions of the drug and all the DPs were performed by using toxicity prediction softwares viz., TOPKAT, LAZAR and Discovery Studio ADMET. The results of in-silico toxicity studies revealed that acebutolol(0.967) and DP-I(0.986) were found to be carcinogenic, while acebutolol(0.490) and DP-IV(0.437) were found to be hepatotoxic.
基金The Grant-Holder-Linked Bursary received from the National Research Foundation and the bursary granted by the Department of Chemical Technology to Mr. A. A
文摘Synthesised triphenylphosphine-linked multiwalled carbon nanotubes （Tpp-MWCNTs） were used to study the adsorption of nickel in aqueous solutions and their adsorption capabilities were compared with purified MWCNTs.The adsorption capacity increased with an increase in pH for all adsorbents.The adsorption equilibrium was reached in 40 and 30 min for purified MWCNTs and Tpp-MWCNTs,respectively.Both Freundlich and Langmuir isotherms used to investigate the adsorption process fitted the experimental data well with the correlation coefficient R 2 close to 1 for all adsorbents.On the other hand,the experimental data fitted well with a pseudo secondorder model.The speciation of nickel also influenced the adsorption on the purified and Tpp-MWCNTs.The adsorbents used in this study showed superior adsorption capacity when compared to other adsorbents reported in the literature.
文摘Differently substituted benzimidazoles have been synthesized in very good yields in solvent-free conditions from o-phenylenediamine and aldehydes in the presence of BF3·OEt2 as a catalyst. The method is applicable to aromatic, unsaturated and aliphatic aldehydes and to substituted o-phenylenediamines without significant differences.
基金Project supported by Anguran Lead and Zinc Company(55/G/93)
文摘At present, the use of rare earth elements（REEs） has become an inevitable necessity in many modern industries. In general, liquid extraction is the best commercial method for extracting REEs due to its ability to control high volumes of liquids with electrical load. With the aim of improving a separation technology that would be superior to the existing extraction systems, the extraction behaviors of La（Ⅲ）,Pr（Ⅲ）, and Nd（Ⅲ） from an HCI medium with Cyanex 272 in the presence of the complexing agent lactic acid（HLac） and auxiliary agents citric acid（H3 Cit）, acetic acid（HAc）, and Titriplex Ⅲ have been reported.The effect of pH and lactic acid concentration has been examined. The use of lactic acid as a complexing agent leading to a high extraction of REEs with Cyanex 272 at pH = 5 was compared with systems without lactic acid. The results show that the use of acetic acid along with lactic acid leads to an increase in the extraction percentage of LREEs. While use of citric acid and Titriplex Ⅲ reduces the extraction percentage of LREEs. Finally, the presence of Titriplex Ⅲ together with lactic acid could lead to an increase in the separation factor of Pr and Nd.
