The objective of the study was to investigate the presence and the activity of quantum dots nanoparticles in colored wastewaters.The special interest is devoted to the investigation of their role in the typical treatm...The objective of the study was to investigate the presence and the activity of quantum dots nanoparticles in colored wastewaters.The special interest is devoted to the investigation of their role in the typical treatment of water or wastewater,studying their influence on the effectiveness of applied treatments methods.The standard chemical processes for water treatment and disinfection （direct UV photolysis and direct ozonation） were applied for the degradation of colored organic pollutant,reactive azo dye,in the presence/absence of CdSe/ZnS core-shells quantum dots.The obtained results indicated that investigated nanoparticles inhibit the overall efficiency of applied processes,especially in the case of direct UV photolysis,although catalytic effect might be expected in part due to the semiconductor nature of quantum dots.Such results lead to a conclusion that CdSe/ZnS nanoparticles behave as additional pollutants in the system.They should be removed from the system prior the treatment,because their presence could decrease the efficiency,i.e.,prolong the time of treatment and correspondingly increase the costs of the treatment process.展开更多
This study explored the removal of five veterinary pharmaceuticals （VPs） （sulfamethoxazole （SMETOX）, trimethoprim （TMP）, ciprofloxacin （CIPRO）, dexamethasone （DEXA） and febantel （FEBA）） from different wa...This study explored the removal of five veterinary pharmaceuticals （VPs） （sulfamethoxazole （SMETOX）, trimethoprim （TMP）, ciprofloxacin （CIPRO）, dexamethasone （DEXA） and febantel （FEBA）） from different water matrices （Milli-Q water, model water, tap water and real pharmaceutical wastewater using four types of nanofiltration （NF） membranes （NF90, NF270, NF and HL） and two reverse osmosis （RO） membranes （LFC-1 and XLE）. All VPs were added to different water matrices at a concentration of 10 mg/L. Rejections of VPs and water flux were measured. The rejection increased with increase of molecular weight. The highest rejections were obtained with RO membranes （LFC-1, XLE） and tight NF （NF90） membrane. In general, the rejection of VPs was higher in model water and tap water than in Milli-Q water, but the water flux was lower. This was mainly explained by ion adsorption inside the membranes pores. Narrower pore size counteracted the effect of presence of low concentration of natural organic matter （NOM） in tap water. The NOM was assumed to enhance the adsorption of VPs onto membrane surface, increased the size exclusion and electrostatic repulsion also appeared during the transport. Investigated water matrices had influence on water flux decline due to their complexity.展开更多
Naturalfibre(NFR)reinforced functional polymer composites are quickly becoming an indispensable sustainable material in the transportation industry because of their lightweight,lower cost in manufacture,and adaptabilit...Naturalfibre(NFR)reinforced functional polymer composites are quickly becoming an indispensable sustainable material in the transportation industry because of their lightweight,lower cost in manufacture,and adaptability to a wide variety of goods.However,the major difficulties of using thesefibres are their existing poor dimensional stability and the extreme hydrophilicity.In assessing the mechanical properties(MP)of composites,the interfacial bonding(IB)happening between the NFR and the polymer matrix(PM)plays an incredibly significant role.When compared to NFR/syntheticfibre hybrid composites,hybrid composites(HC)made up of two separate NFR are less prevalent;yet,these hybrid composites also have the potential to be valuable materials in terms of environmental issues.A new dimension to theflexibility of composites reinforced with NFR is added by the cost-effective manufacture of hybrid composites utilising NFR.The purpose of this study is to offer an over-view of the keyfindings that were presented on hybrid composites.The emphasis was focused on the factors that influence the performance of the naturalfiber composites,diverse approaches to enhancing MP,physical,electri-cal,and thermal characteristics of the HC.HC study in polymer science gains interest for applications in con-struction and automotive industries.展开更多
Fungal pellets of Aspergillus niger 405,Aspergillus ustus 326,and Stachybotrys sp.1103 were used for the removal of humic substances from aqueous solutions.Batchwise biosorption,carried out at pH 6 and 25°C,was m...Fungal pellets of Aspergillus niger 405,Aspergillus ustus 326,and Stachybotrys sp.1103 were used for the removal of humic substances from aqueous solutions.Batchwise biosorption,carried out at pH 6 and 25°C,was monitored spectrophotometrically and the process described with Freundlich’s model.Calculated sorption coeffcients Kf and n showed that A.niger exhibited the highest effciency.A good match between the model and experimental data and a high correlation coeffcient(R2)pointed out to judicious choice of ...展开更多
The present work was done in order to develop and find out suitable conversion methods for coconut husk wastes into value-added products. It is well-known that coconuts husk waste is hydrophobic therefore ethanol with...The present work was done in order to develop and find out suitable conversion methods for coconut husk wastes into value-added products. It is well-known that coconuts husk waste is hydrophobic therefore ethanol with different doses was used as a surfactant to enhance the removal efficiency. Treated samples at different adsorbent amounts, sintering temperatures & sintering time, stirring time, pH, and solution temperatures for color removal of Methylene Blue (MB) & Rhodamine B (RhB) and ammonium concentration were evaluated by using UV-Visible Spectroscopy. At 300°C, results showed complete removal for MB and more than 75% for RhB, whereas removal of ammonium ion reached around 52% when sintering product from husk waste was used. Further investigation was carried out for ammonium ion to understand the desorption kinetic behaviors and isotherm models. Kinetics indicated that desorption of ammonium ion followed pseudo-first order equation. Adsorption thermodynamic parameters such as ΔG, ΔH, and ΔS followed Van’t Hoff plot for adsorption and found to be negative which indicated that the adsorption process for ammonium onto coconut husk was physical, spontaneous and exothermic.展开更多
In the present study reduction of nitrogen oxides using reburning technology, during combustion of sewage sludge (fuel I) and the mixture of sewage sludge, wasted bleaching earth and CaO (fuel II), was carried out. Th...In the present study reduction of nitrogen oxides using reburning technology, during combustion of sewage sludge (fuel I) and the mixture of sewage sludge, wasted bleaching earth and CaO (fuel II), was carried out. The experimental works were conducted in a laboratory-scale fluidized bed reactor (power up to 10 kW) with application of two types of beds: chemically inert bed (sand) and chemically active bed (CaO). The second combustion (reburning) zone in the reactor was formed by dosing into an area above the bed, additional gaseous fuel (propane). Obtained reduction in emissions of nitrogen oxides in both types of beds was at a level 70% - 79%. Additionally bed of CaO has the desulfurizing effect and also reduces the CO concentration in the exhaust fumes. A significant drawback of active bed is the adverse effect on increase of the primary NO which enters the second combustion zone. The result of this fact is higher NOx emission during combustion of the same fuel in bed of CaO in comparison to the combustion of this fuel in the sand bed, when the same maximum degree of reduction of NOx will be obtained for both types of beds.展开更多
Due to their excellent dielectric properties and the rapid response to microwave irradiation,silicon carbide nanowhiskers(SiCNWs)were employed as microwave susceptor in this study to absorb microwave and locally melt ...Due to their excellent dielectric properties and the rapid response to microwave irradiation,silicon carbide nanowhiskers(SiCNWs)were employed as microwave susceptor in this study to absorb microwave and locally melt the surrounding polypropylene(PP)substrates for the joining of PP substrates.Complete welded joint is formed after the melted PP was cooled and resolidified.Other than microwave susceptor,SiCNWs also acted as the nanofillers in strengthening the welded joint through the formation of SiCNWs reinforced PP nanocomposite at the interface of PP substrates.Besides,the effect of microwave power on the microwave welding of PP substrates using SiCNWs as susceptor was studied and reported.It was found that the tensile strength and modulus of elasticity of the welded joint improved as microwave power increased.However,it deteriorates the flexibility of the welded joint as high stiffness SiCNWs were incorporated deeper into the PP matrix which restricted the PP chain mobility.Aside from microwave power,clamping pressure is also critical in determining the mechanical properties of a welded joint.When compared to unclamped welded joint,the tensile strength,modulus of elasticity and flexibility of welded joint subjected to clamping pressure improved drastically.Moreover,the tensile strength of welded joint increased when the clamping pressure was increased from P1 to P3,but decreased when the clamping pressure was further increased to P4 due to the occurrence of flashing at welded joint.The formation mechanism of SiCNWs reinforced PP welded joint was also proposed in this study.Compared to conventional welding,this welding process is easy,straightforward and is able to produce welded joint with outstanding mechanical properties via precise controlling of the processing parameters.Thus,microwave welding is thought to offer an option for the joining of thermoplastics and other applications.展开更多
The production of chemicals from biomass is a very challenging process due to its diverse chemical composition. Lignin, cellulose and hemicellulose are the three main biopolymers of wood biomass, with cell walls ＆pla...The production of chemicals from biomass is a very challenging process due to its diverse chemical composition. Lignin, cellulose and hemicellulose are the three main biopolymers of wood biomass, with cell walls ＆plant origin. Lignin has been chosen for the present studies due to its range of different linkages and structures. The present work involved a computational study of the most dominant lignin dimers and their vibrational structures, based on the Density Functional Theory method. Full geometry optimization of the compartments used the StoBe code with cluster model and non-local functional （RPBE） approach. The calculations of the vibrational frequencies were performed with harmonic approximations as well as an anharmonicity fit in the Morse potential function, as implemented in the StoBe code. In the case oflignin, the calculations included three different precursors based on： coumaryl alcohol, coniferyl alcohol and sinapyl alcohol. To represent the cellulose and hemicellulose derivatives, selected aldopentoses and aldohexoses （arabinose, xylose, glucose, galactose, and mannose） were considered. Presented here are the theoretical investigations for a variety of biomass derived compounds, to give the possibility of obtaining a theoretical VBD （Vibrations Basis Database） for experimental spectra interpretation. Such a database could be further used in the preliminary composition assessment of biomass derived substrates, which will be discussed here in more detail.展开更多
The thermodynamic aspect of a compression type heat pump （HP） is briefly described and special attention is given to investigation of condensing temperature influence on heat pump efficiency in heating mode, express...The thermodynamic aspect of a compression type heat pump （HP） is briefly described and special attention is given to investigation of condensing temperature influence on heat pump efficiency in heating mode, expressed by its coefficient of performance （COP）. Heat pumps are usually applied for the purposes of heating and cooling of energy efficient buildings where they have advantages in low-temperature systems, as it is well documented in the paper. The comparison of real thermodynamic processes with thermodynamically most favorable Camot＇s process is made. The results in the paper show that COP is diminishing with increasing of condensing temperature and also depends on real properties of working fluids. The impact of compressor efficiency for two real working media is also analyzed in the paper. There is significant diminishing of COP with diminishing of compressor efficiency. The intension of the paper is to help better understanding of this very effective and prosperous technology, and to encourage its development, production, and efficient application.展开更多
The metal-doping into the photocatalyst was evaluated for the photocatalytic degradation of bisphenol A in aqueous solution with ZnO powder. Au/ZnO, Ag/ZnO and Cu/ZnO were tested in the present work. Ag-doping ZnO was...The metal-doping into the photocatalyst was evaluated for the photocatalytic degradation of bisphenol A in aqueous solution with ZnO powder. Au/ZnO, Ag/ZnO and Cu/ZnO were tested in the present work. Ag-doping ZnO was effective for the improvement of efficiency for the photocatalytic degradation of bisphenol A in water. The optimum doping concentration of silver was found to be 3 wt%. The pseudo first-order rate constant with 3 wt% Ag/ZnO was 1.3 times better compared with bare ZnO. The photocatalytic degradation of treatment for the wastewater containing bisphenol A is simple, easy handling and low cost.展开更多
The effect of heat treatment for rice husk was investigated on the removal of arsenite in ground water by the adsorption onto the rice husk surface. The heat treatment was performed at the temperature from 80<sup&g...The effect of heat treatment for rice husk was investigated on the removal of arsenite in ground water by the adsorption onto the rice husk surface. The heat treatment was performed at the temperature from 80<sup>o</sup>C to 300<sup>o</sup>C in the closed system under anoxic environment. The continuous adsorption column method was applied for the removal of arsenite. The removal efficiency (75%) with rice husk treated at 150<sup>o</sup>C was better compared to those (54%) obtained with untreated rice husk. Therefore, the heat treatment of rice husk at relatively low temperature was effective for the enhancement of arsenic removal from water. The treatment conditions of As removal from aqueous solution were optimized. The developed treatment technique was applied into the real ground water sample in Bangladesh. The As concentration in sample water after treatment was approximately 18 and 8 μg/L, which was below the WHO guideline value of maximum admissible level of arsenic in ground water for Bangladesh (50 μg/L). The developed technique might become a potential avenue for simple and low cost arsenic removal methods.展开更多
Awareness of dust explosion hazards during silo filling operation is important for safety measures. Thus, information on particles-air flow field is required to assess the likelihood of the hazard. Flow field visualiz...Awareness of dust explosion hazards during silo filling operation is important for safety measures. Thus, information on particles-air flow field is required to assess the likelihood of the hazard. Flow field visualization via experimental investigation associated with difficulties and risks. Hence, in the present study, a modeling formulation using commercial computational fluid dynamics (CFD) code, FLUENT software was employed to predict an insight of flow field distribution, in terms of mean and root mean square (RMS) velocities vectors in cylindrical silo during axial filling. According to the simulation results, predicted flow field has a great influence to the silo height and distance to the silo wall due to gravitational force and movement of fugitive dust and re-circulation of air. The results showed that the predicted data were in very good agreement with experimental data obtained from the literature. The maximum error was around 10%. The study has gone some way towards enhancing our understanding of the particles-air behavior inside industrial equipments during filling operation.展开更多
Elastomeric polyurethanes were prepared from a reference polyurethane system modified with biobased polyols synthesized using rapeseed or palm oils.The reference material was modified by replacement of the commercial ...Elastomeric polyurethanes were prepared from a reference polyurethane system modified with biobased polyols synthesized using rapeseed or palm oils.The reference material was modified by replacement of the commercial polyol by 10%of biopolyols and also by addition of sisal fibers up to 5 wt%.The higher functionality of the biopolyols increased the crosslinking density of the networks and this was reflected by an increase in hardness and a decrease in water absorption.The effect of the sisal fibers mainly improved the mechanical and thermomechanical properties of the system with rapeseed oil because of good dispersion and strong fiber-matrix interaction.The system containing palm oil polyol corresponded to an initial formulation of high viscosity and,consequently,the resulting composites presented lower densities than the theoretically expected ones.These results are associated with fiber dispersion problems in the initial reactive mixture.展开更多
Miscanthus grows well in some marginal and contaminated soils, and it has the potential to be used as a biofuel. Copper and cobalt are heavy metals that sometimes are present as contaminants in soils at concentrations...Miscanthus grows well in some marginal and contaminated soils, and it has the potential to be used as a biofuel. Copper and cobalt are heavy metals that sometimes are present as contaminants in soils at concentrations that may impact the safety of products that are harvested. Laboratory research has been conducted with Miscanthus sacchariflorus M. to investigate metal uptake of copper and cobalt because metal concentrations in the harvested parts of miscanthus are important for biofuel applications. The results show that the use of miscanthus for biofuel from soil contaminated by heavy metals depends mainly on the nature of contaminated metals: cobalt was detected only for highest treated concentration of metal and mainly in the roots. The highest concentration of copper was detected in the roots however this metal was detected in stems and leaves of miscanthus as well. Miscanthus biomass harvested from cobalt contaminated soil may be used for energy production because the harvested part accumulated only limited traces of the metal. The experimental results are in reasonable agreement with other results from the literature.展开更多
The photocatalytic activity of catalysts depends on the energy-harvesting ability and the separation or transport of photogenerated carriers.The light absorption capacity of graphitic carbon nitride(g-C_(3)N_(4))-base...The photocatalytic activity of catalysts depends on the energy-harvesting ability and the separation or transport of photogenerated carriers.The light absorption capacity of graphitic carbon nitride(g-C_(3)N_(4))-based composites can be enhanced by adjusting the surface plasmon resonance(SPR)of noble metal nanoparticles(e.g.,Cu,Au,and Pd)in the entire visible region.Adjustments can be carried out by varying the nanocomponents of the materials.The SPR of noble metals can enhance the local electromagnetic field and improve interband transition,and resonant energy transfer occurs from plasmonic dipoles to electron-hole pairs via near-field electromagnetic interactions.Thus,noble metals have emerged as relevant nanocomponents for g-C_(3)N_(4) used in CO_(2) photoreduction and water splitting.Herein,recent key advances in noble metals(either in single atom,cluster,or nanoparticle forms)and composite photocatalysts based on inorganic or organic nanocomponent-incorporated g-C_(3)N_(4) nanosheets are systematically discussed,including the applications of these photocatalysts,which exhibit improved photoinduced charge mobility in CO_(2) photoconversion and H2 production.Issues related to the different types of multi-nanocomponent heterostructures(involving Schottky junctions,Z-/S-scheme heterostructures,noble metals,and additional semiconductor nanocomponents)and the adjustment of dimensionality of heterostructures(by incorporating noble metal nanoplates on g-C_(3)N_(4) forming 2D/2D heterostructures)are explored.The current prospects and possible challenges of g-C_(3)N_(4) composite photocatalysts incorporated with noble metals(e.g.,Au,Pt,Pd,and Cu),particularly in water splitting,CO_(2) reduction,pollution degradation,and chemical conversion applications,are summarized.展开更多
In this work,Epoxidized natural rubber/sawdust short fiber(ENR-50/SD)composites at different fiber content(5,10,15 and 20 phr)and size(fine size at 60–100μm and coarse size at 10–20 mm)were prepared using two-roll ...In this work,Epoxidized natural rubber/sawdust short fiber(ENR-50/SD)composites at different fiber content(5,10,15 and 20 phr)and size(fine size at 60–100μm and coarse size at 10–20 mm)were prepared using two-roll mill and electrical-hydraulic hot press machine respectively.Curing characteristics,water uptake,tensile,morphological,physical,and thermal properties of the composites were investigated.Results indicated that the scorch time and cure time became shorter whereas torque improved as SD content increase.Though the decline of tensile strength and elongation at break values,modulus,hardness and crosslinking density have shown enhancements with the increasing of SD content.The water uptake percentage of all samples has shown an increasing as SD content increase.However,the low SD content,particularly fine size have presented lower water uptake.The temperature of weight%loss(5 and 50 wt%loss)of 5 phr SD(low content)have recorded higher temperature compared to 20 phr SD(high content)in the rubber composites,which indicated higher thermal stability.The fine size of SD has recorded better overall properties than SD coarse size at same loading in the rubber composites.展开更多
This study presents an overview on graphene synthesis,fabrication and different characterization techniques utilized in the production.Since its discovery in 2004 by Andre Geim and Kostya Novoselov several research ar...This study presents an overview on graphene synthesis,fabrication and different characterization techniques utilized in the production.Since its discovery in 2004 by Andre Geim and Kostya Novoselov several research articles have been published globally to this effect,owing to graphene’s extraordinary,and exclusive characteristics which include optical transparency,excellent thermal,and mechanical properties.The properties and applications of this two-dimensional carbon crystal composed of single-layered material have created new avenues for the development of high-performance future electronics and technologies in energy storage and conversion for the sustainable energy.However,despite its potential and current status globally the difficulty in the production of monolayer graphene sheet still persists.Therefore,this review highlighted two approaches in the synthesis of graphene,which are the top-down and bottom-up approaches and examined the advantages and failings of the methods involved.In addition,the prospects and failings of these methods are investigated,as they are essential in optimizing the production method of graphene vital for expanding the yield,and producing high-quality graphene.展开更多
Luminosity and contrast variation problems are among the most challenging tasks in the image processing field,significantly improving image quality.Enhancement is implemented by adjusting the dark or bright intensity ...Luminosity and contrast variation problems are among the most challenging tasks in the image processing field,significantly improving image quality.Enhancement is implemented by adjusting the dark or bright intensity to improve the quality of the images and increase the segmentation performance.Recently,numerous methods had been proposed to normalise the luminosity and contrast variation.A new approach based on a direct technique using statistical data known as Hybrid Statistical Enhancement(HSE)is presented in this study.TheHSE method uses themean and standard deviation of a local and global neighbourhood and classified the pixel into three groups;the foreground,border,and problematic region(contrast&luminosity).The datasets,namely weld defect images,were utilised to demonstrate the effectiveness of the HSE method.The results from the visual and objective aspects showed that the HSE method could normalise the luminosity and enhance the contrast variation problem effectively.The proposed method was compared to the two(2)populor enhancement methods which is Homomorphic Filter(HF)and Difference of Gaussian(DoG).To prove the HSE effectiveness,a few image quality assessments were presented,and the results were discussed.The HSE method achieved a better result compared to the other methods,which are Signal Noise Ratio(8.920),Standard Deviation(18.588)and Absolute Mean Brightness Error(9.356).In conclusion,implementing the HSE method has produced an effective and efficient result for background correction and quality images improvement.展开更多
The granulometric properties of active pharmaceutical ingredients(APIs)have significance in the pharmaceutical industry because they affect the handling of powders and thus the efficiency of their production.Ceritinib...The granulometric properties of active pharmaceutical ingredients(APIs)have significance in the pharmaceutical industry because they affect the handling of powders and thus the efficiency of their production.Ceritinib,an anaplastic lymphoma kinase inhibitor used in the treatment of non-small cell lung cancer,exhibits platy crystals,which results in low flowability and compressibility and negatively affects its production and pharmaceutical application.Spherical crystallization is a promising method for improving the granulometric properties of APIs by transforming unfavorable particle shapes into a more favorable spherical form.The aim of this research was to improve the granulometric properties of ceritinib through a combined spherical crystallization method in a system containing tetrahydrofuran as the solvent,water with polyvinylpyrrolidone as the antisolvent,and heptane as the bridging liquid.Experimental design was employed to examine and mathematically describe the influence of the solvent fractions in the selected system on the roundness of the obtained crystals and consequently their compressibility.Spherical crystals of ceritinib with high roundness and improved compressibility compared to powdered ceritinib were obtained.The enhanced powder characteristics facilitate the optimization of the production process,potentially minimizing the necessary number of process steps and increasing efficiency.展开更多
In the present work,bimetallic silver/zinc was applied into the degradation of trihalomethanes,THMs:CHCl_(3),CHBrCl_(2),CHBr_(2)Cl,and CHBr_(3).The kinetics reaction rates and removal efficiencies of the THM compound ...In the present work,bimetallic silver/zinc was applied into the degradation of trihalomethanes,THMs:CHCl_(3),CHBrCl_(2),CHBr_(2)Cl,and CHBr_(3).The kinetics reaction rates and removal efficiencies of the THM compound mixtures,in the aqueous solutions,were investigated.Batch experiments were conducted under mild conditions,ambient temperature,and pressure.The primary degradation reaction followed a pseudo-first-order kinetic law.The first-order rate constants and the degradation efficiencies followed the decreasing order of CHBr_(3)>CHBr_(2)Cl>CHBrCl_(2)>CHCl_(3).The bond dissociation energy and hydrophilic/hydrophobic characteristics of the THM compounds may become the most important parameters affecting the degradation kinetics and efficiency by bimetallic Ag/Zn.展开更多
基金both the US Army Engineer Research and Development Center,Vicksburg,MS,USA (throughout DOD contracts # W912HZ-06-C-0057 and # W912HZ-06-C-096)Ministry of Science,Education and Sports of Republic of Croatia (Project #125-1253092-1981) for funding this work
文摘The objective of the study was to investigate the presence and the activity of quantum dots nanoparticles in colored wastewaters.The special interest is devoted to the investigation of their role in the typical treatment of water or wastewater,studying their influence on the effectiveness of applied treatments methods.The standard chemical processes for water treatment and disinfection （direct UV photolysis and direct ozonation） were applied for the degradation of colored organic pollutant,reactive azo dye,in the presence/absence of CdSe/ZnS core-shells quantum dots.The obtained results indicated that investigated nanoparticles inhibit the overall efficiency of applied processes,especially in the case of direct UV photolysis,although catalytic effect might be expected in part due to the semiconductor nature of quantum dots.Such results lead to a conclusion that CdSe/ZnS nanoparticles behave as additional pollutants in the system.They should be removed from the system prior the treatment,because their presence could decrease the efficiency,i.e.,prolong the time of treatment and correspondingly increase the costs of the treatment process.
基金supported by the Croatian Ministry of Science, Education and Sports Projects: 125-1253008-3009 membrane and adsorption processes for removal of organic compounds in water treatment, 125-1253008-1350 advanced analytical methods for pharmaceuticals determination in the environmentUKF project 05/08: Reduction of environmental risks posed by pharmaceuticals and their degradation products in process wastewaters, through RO/NF membrane treatment (REPHAD)
文摘This study explored the removal of five veterinary pharmaceuticals （VPs） （sulfamethoxazole （SMETOX）, trimethoprim （TMP）, ciprofloxacin （CIPRO）, dexamethasone （DEXA） and febantel （FEBA）） from different water matrices （Milli-Q water, model water, tap water and real pharmaceutical wastewater using four types of nanofiltration （NF） membranes （NF90, NF270, NF and HL） and two reverse osmosis （RO） membranes （LFC-1 and XLE）. All VPs were added to different water matrices at a concentration of 10 mg/L. Rejections of VPs and water flux were measured. The rejection increased with increase of molecular weight. The highest rejections were obtained with RO membranes （LFC-1, XLE） and tight NF （NF90） membrane. In general, the rejection of VPs was higher in model water and tap water than in Milli-Q water, but the water flux was lower. This was mainly explained by ion adsorption inside the membranes pores. Narrower pore size counteracted the effect of presence of low concentration of natural organic matter （NOM） in tap water. The NOM was assumed to enhance the adsorption of VPs onto membrane surface, increased the size exclusion and electrostatic repulsion also appeared during the transport. Investigated water matrices had influence on water flux decline due to their complexity.
文摘Naturalfibre(NFR)reinforced functional polymer composites are quickly becoming an indispensable sustainable material in the transportation industry because of their lightweight,lower cost in manufacture,and adaptability to a wide variety of goods.However,the major difficulties of using thesefibres are their existing poor dimensional stability and the extreme hydrophilicity.In assessing the mechanical properties(MP)of composites,the interfacial bonding(IB)happening between the NFR and the polymer matrix(PM)plays an incredibly significant role.When compared to NFR/syntheticfibre hybrid composites,hybrid composites(HC)made up of two separate NFR are less prevalent;yet,these hybrid composites also have the potential to be valuable materials in terms of environmental issues.A new dimension to theflexibility of composites reinforced with NFR is added by the cost-effective manufacture of hybrid composites utilising NFR.The purpose of this study is to offer an over-view of the keyfindings that were presented on hybrid composites.The emphasis was focused on the factors that influence the performance of the naturalfiber composites,diverse approaches to enhancing MP,physical,electri-cal,and thermal characteristics of the HC.HC study in polymer science gains interest for applications in con-struction and automotive industries.
文摘Fungal pellets of Aspergillus niger 405,Aspergillus ustus 326,and Stachybotrys sp.1103 were used for the removal of humic substances from aqueous solutions.Batchwise biosorption,carried out at pH 6 and 25°C,was monitored spectrophotometrically and the process described with Freundlich’s model.Calculated sorption coeffcients Kf and n showed that A.niger exhibited the highest effciency.A good match between the model and experimental data and a high correlation coeffcient(R2)pointed out to judicious choice of ...
文摘The present work was done in order to develop and find out suitable conversion methods for coconut husk wastes into value-added products. It is well-known that coconuts husk waste is hydrophobic therefore ethanol with different doses was used as a surfactant to enhance the removal efficiency. Treated samples at different adsorbent amounts, sintering temperatures & sintering time, stirring time, pH, and solution temperatures for color removal of Methylene Blue (MB) & Rhodamine B (RhB) and ammonium concentration were evaluated by using UV-Visible Spectroscopy. At 300°C, results showed complete removal for MB and more than 75% for RhB, whereas removal of ammonium ion reached around 52% when sintering product from husk waste was used. Further investigation was carried out for ammonium ion to understand the desorption kinetic behaviors and isotherm models. Kinetics indicated that desorption of ammonium ion followed pseudo-first order equation. Adsorption thermodynamic parameters such as ΔG, ΔH, and ΔS followed Van’t Hoff plot for adsorption and found to be negative which indicated that the adsorption process for ammonium onto coconut husk was physical, spontaneous and exothermic.
文摘In the present study reduction of nitrogen oxides using reburning technology, during combustion of sewage sludge (fuel I) and the mixture of sewage sludge, wasted bleaching earth and CaO (fuel II), was carried out. The experimental works were conducted in a laboratory-scale fluidized bed reactor (power up to 10 kW) with application of two types of beds: chemically inert bed (sand) and chemically active bed (CaO). The second combustion (reburning) zone in the reactor was formed by dosing into an area above the bed, additional gaseous fuel (propane). Obtained reduction in emissions of nitrogen oxides in both types of beds was at a level 70% - 79%. Additionally bed of CaO has the desulfurizing effect and also reduces the CO concentration in the exhaust fumes. A significant drawback of active bed is the adverse effect on increase of the primary NO which enters the second combustion zone. The result of this fact is higher NOx emission during combustion of the same fuel in bed of CaO in comparison to the combustion of this fuel in the sand bed, when the same maximum degree of reduction of NOx will be obtained for both types of beds.
基金financially supported by the Department of Education,Ministry of Education Malaysia(MOE)through Fundamental Research Grant Scheme(FRGS/1/2019/TK05/UNIMAP/02/7)[FRGS 9003-00729]。
文摘Due to their excellent dielectric properties and the rapid response to microwave irradiation,silicon carbide nanowhiskers(SiCNWs)were employed as microwave susceptor in this study to absorb microwave and locally melt the surrounding polypropylene(PP)substrates for the joining of PP substrates.Complete welded joint is formed after the melted PP was cooled and resolidified.Other than microwave susceptor,SiCNWs also acted as the nanofillers in strengthening the welded joint through the formation of SiCNWs reinforced PP nanocomposite at the interface of PP substrates.Besides,the effect of microwave power on the microwave welding of PP substrates using SiCNWs as susceptor was studied and reported.It was found that the tensile strength and modulus of elasticity of the welded joint improved as microwave power increased.However,it deteriorates the flexibility of the welded joint as high stiffness SiCNWs were incorporated deeper into the PP matrix which restricted the PP chain mobility.Aside from microwave power,clamping pressure is also critical in determining the mechanical properties of a welded joint.When compared to unclamped welded joint,the tensile strength,modulus of elasticity and flexibility of welded joint subjected to clamping pressure improved drastically.Moreover,the tensile strength of welded joint increased when the clamping pressure was increased from P1 to P3,but decreased when the clamping pressure was further increased to P4 due to the occurrence of flashing at welded joint.The formation mechanism of SiCNWs reinforced PP welded joint was also proposed in this study.Compared to conventional welding,this welding process is easy,straightforward and is able to produce welded joint with outstanding mechanical properties via precise controlling of the processing parameters.Thus,microwave welding is thought to offer an option for the joining of thermoplastics and other applications.
文摘The production of chemicals from biomass is a very challenging process due to its diverse chemical composition. Lignin, cellulose and hemicellulose are the three main biopolymers of wood biomass, with cell walls ＆plant origin. Lignin has been chosen for the present studies due to its range of different linkages and structures. The present work involved a computational study of the most dominant lignin dimers and their vibrational structures, based on the Density Functional Theory method. Full geometry optimization of the compartments used the StoBe code with cluster model and non-local functional （RPBE） approach. The calculations of the vibrational frequencies were performed with harmonic approximations as well as an anharmonicity fit in the Morse potential function, as implemented in the StoBe code. In the case oflignin, the calculations included three different precursors based on： coumaryl alcohol, coniferyl alcohol and sinapyl alcohol. To represent the cellulose and hemicellulose derivatives, selected aldopentoses and aldohexoses （arabinose, xylose, glucose, galactose, and mannose） were considered. Presented here are the theoretical investigations for a variety of biomass derived compounds, to give the possibility of obtaining a theoretical VBD （Vibrations Basis Database） for experimental spectra interpretation. Such a database could be further used in the preliminary composition assessment of biomass derived substrates, which will be discussed here in more detail.
文摘The thermodynamic aspect of a compression type heat pump （HP） is briefly described and special attention is given to investigation of condensing temperature influence on heat pump efficiency in heating mode, expressed by its coefficient of performance （COP）. Heat pumps are usually applied for the purposes of heating and cooling of energy efficient buildings where they have advantages in low-temperature systems, as it is well documented in the paper. The comparison of real thermodynamic processes with thermodynamically most favorable Camot＇s process is made. The results in the paper show that COP is diminishing with increasing of condensing temperature and also depends on real properties of working fluids. The impact of compressor efficiency for two real working media is also analyzed in the paper. There is significant diminishing of COP with diminishing of compressor efficiency. The intension of the paper is to help better understanding of this very effective and prosperous technology, and to encourage its development, production, and efficient application.
文摘The metal-doping into the photocatalyst was evaluated for the photocatalytic degradation of bisphenol A in aqueous solution with ZnO powder. Au/ZnO, Ag/ZnO and Cu/ZnO were tested in the present work. Ag-doping ZnO was effective for the improvement of efficiency for the photocatalytic degradation of bisphenol A in water. The optimum doping concentration of silver was found to be 3 wt%. The pseudo first-order rate constant with 3 wt% Ag/ZnO was 1.3 times better compared with bare ZnO. The photocatalytic degradation of treatment for the wastewater containing bisphenol A is simple, easy handling and low cost.
文摘The effect of heat treatment for rice husk was investigated on the removal of arsenite in ground water by the adsorption onto the rice husk surface. The heat treatment was performed at the temperature from 80<sup>o</sup>C to 300<sup>o</sup>C in the closed system under anoxic environment. The continuous adsorption column method was applied for the removal of arsenite. The removal efficiency (75%) with rice husk treated at 150<sup>o</sup>C was better compared to those (54%) obtained with untreated rice husk. Therefore, the heat treatment of rice husk at relatively low temperature was effective for the enhancement of arsenic removal from water. The treatment conditions of As removal from aqueous solution were optimized. The developed treatment technique was applied into the real ground water sample in Bangladesh. The As concentration in sample water after treatment was approximately 18 and 8 μg/L, which was below the WHO guideline value of maximum admissible level of arsenic in ground water for Bangladesh (50 μg/L). The developed technique might become a potential avenue for simple and low cost arsenic removal methods.
文摘Awareness of dust explosion hazards during silo filling operation is important for safety measures. Thus, information on particles-air flow field is required to assess the likelihood of the hazard. Flow field visualization via experimental investigation associated with difficulties and risks. Hence, in the present study, a modeling formulation using commercial computational fluid dynamics (CFD) code, FLUENT software was employed to predict an insight of flow field distribution, in terms of mean and root mean square (RMS) velocities vectors in cylindrical silo during axial filling. According to the simulation results, predicted flow field has a great influence to the silo height and distance to the silo wall due to gravitational force and movement of fugitive dust and re-circulation of air. The results showed that the predicted data were in very good agreement with experimental data obtained from the literature. The maximum error was around 10%. The study has gone some way towards enhancing our understanding of the particles-air behavior inside industrial equipments during filling operation.
文摘Elastomeric polyurethanes were prepared from a reference polyurethane system modified with biobased polyols synthesized using rapeseed or palm oils.The reference material was modified by replacement of the commercial polyol by 10%of biopolyols and also by addition of sisal fibers up to 5 wt%.The higher functionality of the biopolyols increased the crosslinking density of the networks and this was reflected by an increase in hardness and a decrease in water absorption.The effect of the sisal fibers mainly improved the mechanical and thermomechanical properties of the system with rapeseed oil because of good dispersion and strong fiber-matrix interaction.The system containing palm oil polyol corresponded to an initial formulation of high viscosity and,consequently,the resulting composites presented lower densities than the theoretically expected ones.These results are associated with fiber dispersion problems in the initial reactive mixture.
文摘Miscanthus grows well in some marginal and contaminated soils, and it has the potential to be used as a biofuel. Copper and cobalt are heavy metals that sometimes are present as contaminants in soils at concentrations that may impact the safety of products that are harvested. Laboratory research has been conducted with Miscanthus sacchariflorus M. to investigate metal uptake of copper and cobalt because metal concentrations in the harvested parts of miscanthus are important for biofuel applications. The results show that the use of miscanthus for biofuel from soil contaminated by heavy metals depends mainly on the nature of contaminated metals: cobalt was detected only for highest treated concentration of metal and mainly in the roots. The highest concentration of copper was detected in the roots however this metal was detected in stems and leaves of miscanthus as well. Miscanthus biomass harvested from cobalt contaminated soil may be used for energy production because the harvested part accumulated only limited traces of the metal. The experimental results are in reasonable agreement with other results from the literature.
基金supported in part by the projects from the National Natural Science Foundation of China(No.51972145)Jinan Science&Technology Bureau,China(No.2021GXRC109)Science and Technology Program of the University of Jinan,China(No.XKY2118).
文摘The photocatalytic activity of catalysts depends on the energy-harvesting ability and the separation or transport of photogenerated carriers.The light absorption capacity of graphitic carbon nitride(g-C_(3)N_(4))-based composites can be enhanced by adjusting the surface plasmon resonance(SPR)of noble metal nanoparticles(e.g.,Cu,Au,and Pd)in the entire visible region.Adjustments can be carried out by varying the nanocomponents of the materials.The SPR of noble metals can enhance the local electromagnetic field and improve interband transition,and resonant energy transfer occurs from plasmonic dipoles to electron-hole pairs via near-field electromagnetic interactions.Thus,noble metals have emerged as relevant nanocomponents for g-C_(3)N_(4) used in CO_(2) photoreduction and water splitting.Herein,recent key advances in noble metals(either in single atom,cluster,or nanoparticle forms)and composite photocatalysts based on inorganic or organic nanocomponent-incorporated g-C_(3)N_(4) nanosheets are systematically discussed,including the applications of these photocatalysts,which exhibit improved photoinduced charge mobility in CO_(2) photoconversion and H2 production.Issues related to the different types of multi-nanocomponent heterostructures(involving Schottky junctions,Z-/S-scheme heterostructures,noble metals,and additional semiconductor nanocomponents)and the adjustment of dimensionality of heterostructures(by incorporating noble metal nanoplates on g-C_(3)N_(4) forming 2D/2D heterostructures)are explored.The current prospects and possible challenges of g-C_(3)N_(4) composite photocatalysts incorporated with noble metals(e.g.,Au,Pt,Pd,and Cu),particularly in water splitting,CO_(2) reduction,pollution degradation,and chemical conversion applications,are summarized.
文摘In this work,Epoxidized natural rubber/sawdust short fiber(ENR-50/SD)composites at different fiber content(5,10,15 and 20 phr)and size(fine size at 60–100μm and coarse size at 10–20 mm)were prepared using two-roll mill and electrical-hydraulic hot press machine respectively.Curing characteristics,water uptake,tensile,morphological,physical,and thermal properties of the composites were investigated.Results indicated that the scorch time and cure time became shorter whereas torque improved as SD content increase.Though the decline of tensile strength and elongation at break values,modulus,hardness and crosslinking density have shown enhancements with the increasing of SD content.The water uptake percentage of all samples has shown an increasing as SD content increase.However,the low SD content,particularly fine size have presented lower water uptake.The temperature of weight%loss(5 and 50 wt%loss)of 5 phr SD(low content)have recorded higher temperature compared to 20 phr SD(high content)in the rubber composites,which indicated higher thermal stability.The fine size of SD has recorded better overall properties than SD coarse size at same loading in the rubber composites.
文摘This study presents an overview on graphene synthesis,fabrication and different characterization techniques utilized in the production.Since its discovery in 2004 by Andre Geim and Kostya Novoselov several research articles have been published globally to this effect,owing to graphene’s extraordinary,and exclusive characteristics which include optical transparency,excellent thermal,and mechanical properties.The properties and applications of this two-dimensional carbon crystal composed of single-layered material have created new avenues for the development of high-performance future electronics and technologies in energy storage and conversion for the sustainable energy.However,despite its potential and current status globally the difficulty in the production of monolayer graphene sheet still persists.Therefore,this review highlighted two approaches in the synthesis of graphene,which are the top-down and bottom-up approaches and examined the advantages and failings of the methods involved.In addition,the prospects and failings of these methods are investigated,as they are essential in optimizing the production method of graphene vital for expanding the yield,and producing high-quality graphene.
文摘Luminosity and contrast variation problems are among the most challenging tasks in the image processing field,significantly improving image quality.Enhancement is implemented by adjusting the dark or bright intensity to improve the quality of the images and increase the segmentation performance.Recently,numerous methods had been proposed to normalise the luminosity and contrast variation.A new approach based on a direct technique using statistical data known as Hybrid Statistical Enhancement(HSE)is presented in this study.TheHSE method uses themean and standard deviation of a local and global neighbourhood and classified the pixel into three groups;the foreground,border,and problematic region(contrast&luminosity).The datasets,namely weld defect images,were utilised to demonstrate the effectiveness of the HSE method.The results from the visual and objective aspects showed that the HSE method could normalise the luminosity and enhance the contrast variation problem effectively.The proposed method was compared to the two(2)populor enhancement methods which is Homomorphic Filter(HF)and Difference of Gaussian(DoG).To prove the HSE effectiveness,a few image quality assessments were presented,and the results were discussed.The HSE method achieved a better result compared to the other methods,which are Signal Noise Ratio(8.920),Standard Deviation(18.588)and Absolute Mean Brightness Error(9.356).In conclusion,implementing the HSE method has produced an effective and efficient result for background correction and quality images improvement.
基金funded by European Structural and Investment Funds,grant number KK.01.1.1.07.0017(CrystAPC-Crystallization Advanced Process Control).
文摘The granulometric properties of active pharmaceutical ingredients(APIs)have significance in the pharmaceutical industry because they affect the handling of powders and thus the efficiency of their production.Ceritinib,an anaplastic lymphoma kinase inhibitor used in the treatment of non-small cell lung cancer,exhibits platy crystals,which results in low flowability and compressibility and negatively affects its production and pharmaceutical application.Spherical crystallization is a promising method for improving the granulometric properties of APIs by transforming unfavorable particle shapes into a more favorable spherical form.The aim of this research was to improve the granulometric properties of ceritinib through a combined spherical crystallization method in a system containing tetrahydrofuran as the solvent,water with polyvinylpyrrolidone as the antisolvent,and heptane as the bridging liquid.Experimental design was employed to examine and mathematically describe the influence of the solvent fractions in the selected system on the roundness of the obtained crystals and consequently their compressibility.Spherical crystals of ceritinib with high roundness and improved compressibility compared to powdered ceritinib were obtained.The enhanced powder characteristics facilitate the optimization of the production process,potentially minimizing the necessary number of process steps and increasing efficiency.
基金partially supported by the Ministry of Education,Culture,Sports,Science,and Technology of Japan.
文摘In the present work,bimetallic silver/zinc was applied into the degradation of trihalomethanes,THMs:CHCl_(3),CHBrCl_(2),CHBr_(2)Cl,and CHBr_(3).The kinetics reaction rates and removal efficiencies of the THM compound mixtures,in the aqueous solutions,were investigated.Batch experiments were conducted under mild conditions,ambient temperature,and pressure.The primary degradation reaction followed a pseudo-first-order kinetic law.The first-order rate constants and the degradation efficiencies followed the decreasing order of CHBr_(3)>CHBr_(2)Cl>CHBrCl_(2)>CHCl_(3).The bond dissociation energy and hydrophilic/hydrophobic characteristics of the THM compounds may become the most important parameters affecting the degradation kinetics and efficiency by bimetallic Ag/Zn.
