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1.
《Ultrasonics sonochemistry》2014,21(4):1477-1481
The possibility of reducing the use of auxiliaries in conventional cellulose acetate dyeing with Disperse Red 50 using ultrasound technique was studied as an alternative to the standard procedure. Dyeing of cellulose acetate yarn was carried out by using either mechanical agitation alone, with and without auxiliaries, or coupling mechanical and ultrasound agitation in the bath where the temperature range was maintained between 60 and 80 °C.The best results of dyeing kinetics were obtained with ultrasound coupled with mechanical agitation without auxiliaries (90% of bath exhaustion value at 80 °C). Hence the corresponding half dyeing times, absorption rate constants according to Cegarra–Puente modified equation and ultrasound efficiency were calculated confirming the synergic effect of sonication on the dyeing kinetics. Moreover the apparent activation energies were also evaluated and the positive effect of ultrasound added to mechanical agitation was evidenced by the lower value (48 kJ/mol) in comparison with 112 and 169 kJ/mol for mechanical stirring alone with auxiliaries and without, respectively.Finally, the fastness tests gave good values for samples dyed with ultrasound technique even without auxiliaries. Moreover color measurements on dyed yarns showed that the color yield obtained by ultrasound-assisted dyeing at 80 °C of cellulose acetate without using additional chemicals into the dye bath reached the same value yielded by mechanical agitation, but with remarkably shorter time.  相似文献   

2.
There is a growing demand for eco-friendly/non-toxic colorants, specifically for health sensitive applications such as coloration of food and dyeing of child textile/leather garments. Recently, dyes derived from natural sources for these applications have emerged as an important alternative to potentially harmful synthetic dyes and pose need for suitable effective extraction methodologies. The present paper focus on the influence of process parameters for ultrasound assisted leaching of coloring matter from plant materials. In the present work, extraction of natural dye from beetroot using ultrasound has been studied and compared with static/magnetic stirring as a control process at 45 °C. The influence of process parameters on the extraction efficiency such as ultrasonic output power, time, pulse mode, effect of solvent system and amount of beetroot has been studied. The use of ultrasound is found to have significant improvement in the extraction efficiency of colorant obtained from beetroot. Based on the experiments it has been found that a mixture of 1:1 ethanol–water with 80 W ultrasonic power for 3 h contact time provided better yield and extraction efficiency. Pulse mode operation may be useful in reducing electrical energy consumption in the extraction process. The effect of the amount of beetroot used in relation to extraction efficiency has also been studied. Two-stage extraction has been studied and found to be beneficial for improving the yield for higher amounts of beetroot. Significant 8% enhancement in % yield of colorant has been achieved with ultrasound, 80 W as compared to MS process both using 1:1 ethanol–water. The coloring ability of extracted beet dye has been tested on substrates such as leather and paper and found to be suitable for dyeing. Ultrasound is also found to be beneficial in natural dyeing of leather with improved rate of exhaustion. Both the dyed substrates have better color values for ultrasonic beet extract as inferred from reflectance measurement. Therefore, the present study clearly offers efficient extraction methodology from natural dye resources such as beetroot with ultrasound even dispensing with external heating. Thereby, also making eco-friendly non-toxic dyeing of fibrous substances a potential viable option.  相似文献   

3.
Ultrasonics has the potential to reduce the cost and environmental impact of textile processing. This work investigates the effects of ultrasonic irradiation during wool scouring on fibre surface morphologies, fibre mechanical properties, and fibre dyeing abilities. A range of ultrasonic frequencies were used in the scouring bath to examine the forms of fibre cuticle damage. It is observed that wool fibres underwent ultrasonic irradiation at a low frequency have severe modifications of the fibre surface structure. Despite some visible disruptions to the fibre scale structure however, ultrasonic irradiation has shown a negligible impact on the fibre mechanical properties, especially bending abrasion resistance which depends largely on the fibre surface conditions, and is responsible for the handle and pilling propensity of the resultant fabrics. Dyeing abilities were investigated on wool samples using commercially available acid dye and reactive dye. It is found that ultrasonically scoured wool has a quicker dye uptake in the early stage of low temperature dyeing for both acid dye and reactive dye, than the conventionally scoured wool.  相似文献   

4.
A large number of papers of the literature quote dyeing intensification based on the application of ultrasound (US) in the dyeing liquor. Mass transfer mechanisms are described and quantified, nevertheless these experimental results in general refer to small laboratory apparatuses with a capacity of a few hundred millilitres and extremely high volumetric energy intensity. With the strategy of overcoming the scale-up inaccuracy consequent to the technological application of ultrasounds, a dyeing pilot-plant prototype of suitable liquor capacity (about 40 L) and properly simulating several liquor to textile hydraulic relationships was designed by including US transducers with different geometries.Optimal dyeing may be obtained by optimising the distance between transducer and textile material, the liquid height being a non-negligible operating parameter. Hence, mapping the cavitation energy in the machinery is expected to provide basic data on the intensity and distribution of the ultrasonic field in the aqueous liquor. A flat ultrasonic transducer (absorbed electrical power of 600 W), equipped with eight devices emitting at 25 kHz, was mounted horizontally at the equipment bottom.Considering industrial scale dyeing, liquor and textile substrate are reciprocally displaced to achieve a uniform colouration. In this technology a non uniform US field could affect the dyeing evenness to a large extent; hence, mapping the cavitation energy distribution in the machinery is expected to provide fundamental data and define optimal operating conditions. Local values of the cavitation intensity were recorded by using a carefully calibrated Ultrasonic Energy Meter, which is able to measure the power per unit surface generated by the cavitation implosion of bubbles. More than 200 measurements were recorded to define the map at each horizontal plane positioned at a different distance from the US transducer; tap water was heated at the same temperature used for dyeing tests (60 °C). Different liquid flow rates were tested to investigate the effect of the hydrodynamics characterising the equipment.The mapping of the cavitation intensity in the pilot-plant machinery was performed to achieve with the following goals: (a) to evaluate the influence of turbulence on the cavitation intensity, and (b) to determine the optimal distance from the ultrasound device at which a fabric should be positioned, this parameter being a compromise between the cavitation intensity (higher next to the transducer) and the US field uniformity (achieved at some distance from this device).By carrying out dyeing tests of wool fabrics in the prototype unit, consistent results were confirmed by comparison with the mapping of cavitation intensity.  相似文献   

5.
The dyeing of acrylic fabrics using C.I. Astrazon Basic Red 5BL 200% has been studied with both conventional and ultrasonic techniques. The effect of dye concentration, dye bath pH, ultrasonic power, dyeing time and temperature were studied and the resulting shades obtained by dyeing with both techniques were compared. Colour strength values obtained were found to be higher with ultrasonic than with conventional heating. The results of fastness properties of the dyed fabrics were studied. X-ray and Scanning Electron Microscope SEM were carried out on dyed samples using both methods of dyeing to find out an explanation for the better dyeability of acrylic fabrics with (US) method. Dyeing kinetics of acrylic fabrics using C.I. Astrazon Basic Red 5BL 200% using conventional and ultrasonic conditions were compared. The time/dye-uptake isotherms are revealing the enhanced dye-uptake in the second phase of dyeing. The values of dyeing rate constant, half-time of dyeing and standard affinity and ultrasonic efficiency have been calculated and discussed.  相似文献   

6.
Polyaniline-wool (PAN-WF), poly(3,4-ethylenedioxythiophene)-wool (PEDOT-WF), polypyrrole-wool (PPy-WF) fabrics were successfully prepared via atmospheric pressure plasma process. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), Fourier Transform Infrared Spectroscopy (FTIR) and four-probe resistance measurements were used to study the properties of the plasma polymer coated wool fabrics. The effects of the addition of iodine doping on the morphology and electrical properties of the fabrics were examined. The lowest electrical resistance was measured to be 7.7 × 103 Ω cm for PEDOT-I2-WF sample after washing with water two times.  相似文献   

7.
本研究用氮气等离子体固相表面修饰改性对丙纶纤维进行表面处理。用傅立叶变换红外光谱分析改性前后样品表面官能团变化,用扫描电镜分析改性前后样品表面的形貌变化,用紫外可见分光光度计测试样品的上染率。结果表明:等离子体表面处理及丙烯酸接枝后的丙纶纤维表面引入了羰基、胺(氨)基或酰胺等活性基,使丙纶纤维从不可上染到能染上鲜艳的阳离子艳兰,显著改善了丙纶纤维的染色品质。  相似文献   

8.
Red-G dye is one of the main dyes used in the textile industry to dye alpaca wool. Therefore, considering the large volume of processed wool in Perú, the development of efficient technologies for its removal is a present scientific issue. In this study, an integrated system based on hydrodynamic cavitation (HC) and photo-Fenton process was evaluated to remove the Red-G dye. Using a hybrid cavitation device (venturi + orifice plate), the effect of pH was evaluated, achieving 21 % of removal at pH 2 which was more than 80 % higher compared to pH 4 and 6. The effect of temperature was also evaluated in HC-system at pH 2, where percentage of dye degradation increased at lower temperatures (around 20 °C). Then, 50.7 % of dye was removed under optimized condition of HC-assisted Fenton process (FeSO4:H2O2 of 1:30), that value was improved strongly by UV-light incorporation in the HC-system, increasing to 99 % removal efficiency with respect to HC-assisted Fenton process and reducing the time to 15 min. Finally, the developed cavitation device in combination with photo-Fenton process removed efficiently the dye and thus could be considered an interesting option for application to real wastewater.  相似文献   

9.
Detection of environmental pollutant and health hazardous, nitrogen dioxide (NO2) is reported using nanostructured CuO particulates (NPs). Powder X-ray diffraction and field emission scanning electron microscopy were used to probe crystalline phase and morphological details, respectively. Small crystallites of ∼10–12 nm and a strain of 4% were found in the leafy structure of CuO. Raman studies further supported the presence of nanosized CuO phase. This is the first instance of utilizing CuO NPs to detect 5 ppm of NO2 even at a low operating temperature of 50 °C. The highest sensitivity for NO2 was observed at 150 °C, for the first time, in CuO NPs. A low activation energy of 0.18 eV was found for sensing process. The CuO NPs sensor responded to NO2 within a few seconds and recovered totally under a minute. The kinetics of the NO2 gas adsorption on the CuO film surface was described following the Elovich model.  相似文献   

10.
Wet textile washing processes were set up for wool and cotton fabrics to evaluate the potential of ultrasound transducers (US) in improving dirt removal. The samples were contaminated with an emulsion of carbon soot in vegetable oil and aged for three hours in fan oven. Before washing, the fabrics were soaked for 3 min in a standard detergent solution and subsequently washed in a water bath. The dirt removal was evaluated through colorimetric measurements. The total color differences ΔE of the samples were measured with respect to an uncontaminated fabric, before and after each washing cycle. The percentage of ΔE variation obtained was calculated and correlated to the dirt removal. The results showed that the US transducers enhanced the dirt removal and temperature was the parameter most influencing the US efficiency on the cleaning process. Better results were obtained at a lower process temperature.  相似文献   

11.
《Ultrasonics sonochemistry》2014,21(5):1815-1826
This study presents a novel idea to prepare nanocrystalline structure of TiO2 under ambient pressure at 60–65 °C using in situ sonochemical synthesis by hydrolysis of either titanium isopropoxide or titanium butoxide in an acidic aqueous solution. The nano titanium dioxide coated wool fabrics possess significant antibacterial/antifungal activity and self-cleaning property by discoloring Methylene blue stain under sunlight irradiation. This process has no negative effect on cytotoxicity and tensile strength of the sonotreated fabric even reduces alkaline solubility and photoyellowing and improves hydrophilicity. More titanium isopropoxide or titanium butoxide as a precursor led to higher photocatalytic activities of the treated fabrics. Also introducing more ethanol improved the adsorption of TiO2 on the wool fabric surface leading to enhanced photocatalytic activity. EDS and XRD patterns, SEM images, X-ray mapping confirmed the presence of nano TiO2 particles on the fabric surface. The role of both solvent and precursor concentrations on the various properties of the fabric was investigated and the optimized conditions were obtained using response surface methodology.  相似文献   

12.
The present work establishes in depth study of ultrasound assisted preparation of performic acid (PFA) in a continuous flow microstructured reactor. The influence of various parameters viz. formic acid: hydrogen peroxide molar ratio, flow rate, temperature and catalyst loading on the PFA formation were studied in a continuous flow microstructured reactor. In a continuous microstructured reactor in the presence of ultrasonic irradiation, the formation of PFA was found to be dependent on the molar ratio of formic acid: hydrogen peroxide, flow rate of reactants, temperature and catalyst loading (Amberlite IR-120H). The optimized parameter values are 1:1 M ratio, 50 mL/h, 40 °C and 471 mg/cm3 respectively. Further, the performance of Amberlite IR-120H catalyst was evaluated for three successive cycles in continuous microstructured reactor. The performance of catalyst was found to be decreased with the usage of the catalyst and is attributed to neutralization of the sulfonic acid groups, catalyst shrinkage, or loss in pore sites. The experimental results revealed that, for an ultrasound assisted synthesis of PFA in continuous microstructured reactor the observed reaction time was even less than 10 min. The observed intensification in the PFA synthesis process can be attributed to the intense collapse of the cavities formed at low temperature during ultrasonic irradiations, which further improved the heat and mass transfer rates with the formation of H2O2 during the reaction. The combined use of ultrasound and a continuous flow microstructured reactor has proved beneficial process of performic acid synthesis.  相似文献   

13.
Moisturizing creams and lotions are commonly used in daily life for beauty and treatment of different skin conditions such as dryness and wrinkling, and ultrasound stimulation has been used to enhance the delivery of ingredients into skin. However, there is a lack of convenient methods to study the effect of ultrasound stimulation on lotion absorption by skin in vivo. Ultrasound biomicroscopy was adopted as a viable tool in this study to investigate the effectiveness of ultrasound stimulation on the enhancement of lotion delivery into skin. The forearm skin of 10 male and 10 female young subjects was tested at three different sites, including two lotion treatment sites with (Ultrasound Equipment – UE ON) and without (UE OFF) ultrasound stimulation and a control site without any lotion treatment. 1 MHz ultrasound with a duty cycle of 1.7%, a spatial peak temporal peak pressure of 195 kPa and an average power of 0.43 W was used for the stimulation. The skin thickness before, immediately after (0 min), and 15 and 30 min after the treatment was measured by an ultrasound biomicroscopic system (55 MHz). It was found that the skin thickness significantly increased immediately after the lotion treatment for both UE ON (from 1.379 ± 0.187 mm to 1.466 ± 0.182 mm, p < 0.001) and UE OFF (from 1.396 ± 0.193 mm to 1.430 ± 0.194 mm, p < 0.001) groups. Further comparison between the two groups revealed that the skin thickness increase of UE ON group was significantly larger than that of UE OFF group (6.5 ± 2.4% vs. 2.5 ± 1.3%, p < 0.001). Furthermore, it was disclosed that the enhancement of lotion delivery by ultrasound stimulation was more effective for the female subjects than the male subjects (7.6 ± 2.3% vs. 5.4 ± 2.0% immediately after treatment, = 0.017). In conclusion, this study demonstrated that ultrasound biomicroscopy was a feasible method for studying the effectiveness of lotion treatment in vivo, and ultrasound stimulation was effective to enhance the rate of lotion absorption into skin.  相似文献   

14.
The influence of ultrasound (US) on the viscosity of aqueous slurry composing polyacrylic acid (PAA) and alumina was studied. For exposure to an aqueous slurry solution, US waves emitted at three different frequencies of 28, 45, and 100 kHz were used. Results show that the stimulus effect of US on viscosity change was a breakage of the hydrogen bonding networks of alumina and PAA in the slurry solution. That decrease in viscosity was enhanced strongly by US exposure as the output power was increased from 175 to 300 W. In addition, a lower US frequency was effective for slurry viscosity reduction. The reduced viscosity of the slurry also depended on the solution pH. After US was stopped, the viscosity increased gradually and recovered to its original value within about 15 min. The stimulus effect on the viscosity change was cycled by US.  相似文献   

15.
Titania (TiO2) nanorods have been synthesized with controlled size for dye-sensitized solar cells (DSSCs) via hydrothermal route at low hydrothermal temperature of 100 °C for 24 h. The titania nanorods were characterized using XRD, SEM, TEM/HRTEM, UV-vis Spectroscopy, FTIR and BET specific surface area (S BET), as well as pore-size distribution by BJH. The results indicated that the bulk traps and the surface states within the TiO2 nanorods films have enhanced the efficiency of DSSCs. The size of the titania nanorods was 6.7 nm in width and 22 nm in length. The high surface area can provide more sites for dye adsorption, while the fast photoelectron-transfer channel can enhance the photogenerated electron transfer to complete the circuit. The specific surface area S BET was 77.14 m2?g?1 at the synthesis conditions. However, the band gap energy of the obtained titania nanorods was 3.2 eV. The oriented nanorods with appropriate lengths are beneficial in improving the electron transport property and thus leading to the increase of photocurrent, together enhancing the power conversion efficiency. A nearly quantitative absorbed photon-to-electrical current conversion achieved upon excitation at wave length of 550 nm and the power efficiency was enhanced from 5.6 % for commercial TiO2 nanoparticles Degussa (P25) cells to 7.2 % for TiO2 nanorods cells under AM 1.5 illumination (100 mW?cm?2). The TiO2 cells performance was improved due to their high surface area, hierarchically mesoporous structures and fast electron-transfer rate compared with the Degussa (P25).  相似文献   

16.
Root-knot nematodes are one of the plant damaging nematodes in agriculture causing a projected annual yield loss of ∼12 % (∼$160 billion) worldwide. Conventional solutions to control these plant-parasitic nematodes involve chemical nematicides. To reduce the use of harmful chemicals, microalgal extracts can be used as greener alternatives for nematode management. Microalgae produce valuable metabolites, including cyanotoxins which can aid in nematode suppression.In this study, two microalgae species, Trichormus variabilis and Nostoc punctiforme, were treated with ultrasound for intensified recovery of secondary metabolites. Ultrasound results in cell wall disruption of the microalgal species, thus resulting in enhanced release of secondary metabolites. Microalgal biomass was treated with an ultrasound probe at 50 % amplitude, 20 kHz frequency, using water as the extraction medium, for 5–30 min. The extraction efficiency was determined in terms of the total chlorophyll (Chl) content of the extract. Microscopic images of the treated cells were also investigated to gain insight into the effect of the ultrasonication time on the cell morphology. Our results suggest that ultrasonication resulted in the intensified release of secondary metabolites, as established through the total chlorophyll content of the ultrasonicated microalgal samples as well as the microscopic images of the ruptured cells. The best extraction for Trichormus variabilis was achieved with 15 min extraction time where the Total Chl content increased by 29 times (compared to the non-ultrasonicated sample), and for the Nostoc punctiforme, 30 min extraction time gave the highest metabolite recovery of 6.4 times higher than the non-ultrasonicated sample.Ultrasonicated algal extracts were then tested for their nematicidal potential against root-knot nematode, Meloidogyne hapla, in infested field soil samples. Experimental study was conducted using different concentrations of each microalga, Trichormus sp. and Nostoc sp., individually, as well as in combination. The nematode count for the treated soil was compared with that of the control (untreated soil). Ultrasonicated microalgal extracts showed 66% to 100% inhibition on root-knot nematodes in the soil samples tested.  相似文献   

17.
The initial interaction of water vapor with polycrystalline uranium surfaces at low temperatures (LT, 200 K), was studied by combined measurements utilizing Direct Recoil Spectrometry (DRS), Auger electron Spectroscopy (AES) and X-ray Photoelectron Spectroscopy (XPS). Three stages of water dissociation and adsorption can be observed: Stage (1) 0-0.6 oxygen monolayer coverage: full (H2O → O + 2H) dissociation is dominant, coexisting with partial dissociation (H2O → OH + H). In contrast to room temperature, where the adsorption is of a Langmuir type, in the present low temperature case it is a precursor-state type - the oxygen accumulation is linear, indicating that a constant fraction of the water molecules impinging on the surface diffuses to a dissociation and adsorption site. Only minor oxidation of the uranium occurs. Stage (2) 0.6-full oxygen coverage: only partial dissociation occurs. Still only minor oxidation of uranium takes place. Stage (3) buildup of a second hydroxyl layer, concurrent with slow continuous oxidation of uranium. Subsequent heating of the sample after the described exposure was accompanied by additional continuous oxidation. Above ∼230 K, the main process seems to be OH decomposition and desorption. A comparison is made to the dissociation and adsorption processes at room temperature.  相似文献   

18.
Caffeoylquinic acids are existed in many plant species with various biological and pharmacological activities. 3-O-caffeoylquinic acid and 4-O-caffeoylquinic acid are two isomers of caffeoylquinic acids, which may be degraded and transformed to their isomers in processing. The present paper found that the stability of 3- and 4-O-caffeoylquinic acid had decreased with the increasing solution alkalinity. 3-O-caffeoylquinic acid was more stable than 4-O-caffeoylquinic acid at the same condition. During degradation, 3- and 4-O-caffeoylquinic acid were partially converted to their isomers. Additionally, ultrasonic effects on the degradation and isomerization of 3- and 4-O-caffeoylquinic acid at different pH were studied. Ultrasound facilitated the degradation and isomerization of these compounds. The degradation kinetics were described by the Weibull equation. The protective effect of ascorbic acid and epigallocatechin gallate were also explored. Ascorbic acid and epigallocatechin gallate could alleviate the degradation of 3- and 4-O-caffeoylquinic acid under certain conditions.  相似文献   

19.
In this paper, the surface modification of silk fiber using anhydrides to graft the polysaccharide chitosan and dyeing ability of the grafted silk were studied. Silk fiber was degummed and acylated with two anhydrides, succinic anhydride (SA) and phthalic anhydride (PA), in different solvents (dimethyl sulfoxide (DMSO) and N,N-dimethyl formamide (DMF)). The effects of anhydrides, solvents, anhydride concentration, liquor ratio (L:R) and reaction time on acylation of silk were studied. The polysaccharide chitosan was grafted to the acylated silk fiber and dyed by acid dye (Acid Black NB.B). The effects of pH, chitosan concentration, and reaction time on chitosan grafting of acylated silk were investigated. The physical properties show sensible changes regardless of weight gain. Scanning electron microscopy (SEM) analysis showed the presence of foreign materials firmly attached to the surface of silk. FTIR spectroscopy provided evidence that chitosan was grafted onto the acylated silk through the formation of new covalent bonds. The dyeing of the chitosan grafted-acylated silk fiber indicated the higher dye ability in comparison to the acylated and degummed silk samples. The mechanism of chitosan grafting over degummed silk through anhydride linkage was proposed. The findings of this research support the potential production of new environmentally friendly textile fibers. It is worthwhile to mention that the grafted samples have antibacterial potential due to the antibacterial property of chitosan molecules.  相似文献   

20.
A microwave plasma treatment in a down stream configuration was used to modify the natural hydrophobocity of untreated wool fibers. This property is a consequence of the presence of a Fatty acid monolayer (F-layer) on the outermost part of the fiber surface. The wool fibers treated with plasma were analyzed by means of X-ray photoelectron spectroscopy (XPS) without previous exposure to the air. Experiments have been carried out with air, water vapor, oxygen and nitrogen as plasma gas. The “in situ” analysis of the treated samples has permitted to differentiate between the plasma effects and those other linked to the exposure of the fibers to the air after their treatment. The results have evidenced the effects induced by the different active species generated by plasma from the different components of the air. In general, the intensity of CC peaks decreases and that of the CO, CO and OCO increases when using a gas containing oxygen species. Simultaneously, the intensity of the SS groups decreases and that of the sulphonate (SO3) increases. Other changes are also detected in the intensity of the N 1s level. The extent and characteristics of the oxidation and functionalisation of the hydrocarbon chains of the F-layer depend on the nature of gas. Thus, whereas treatments with plasmas of air and water vapor strongly affect the hydrocarbon chains of the F-layer, oxygen is less effective in the oxidation process. It has been also noted that the active species formed in the nitrogen plasma do not induce any significant change in the surface composition of the wool fibers.  相似文献   

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