Synthetic dyes are released into the environment from textile industrial effluents. The discharge of this colored wastewater
into rivers and lakes leads to a reduction in sunlight penetration in natural water bodies, which, in turn, decreases both
photosynthetic activity and dissolved oxygen concentration and is toxic to living beings. Bacterial isolates are optimized
for growth and biomass production before using them for decolorizing dye effluent. The bacterial isolates Bacillus sp. 1 and Bacillus sp. 2 were employed at different percentages by volume with standard nutrient concentration. Of these bacterial isolates
Bacillus sp. 2 recorded maximum color reduction. The pH and electrical conductivity (EC) were reduced in the decolorized effluent,
and a reduction in biologic oxygen demand, chemical oxygen demand, total suspended solids, and total dissolved solids (TDS)
were also observed. 相似文献
The paper describes the effect of molecular mass and copolymer composition on thermal behaviour of homopolymers and copolymers of glycidyl methacrylate and methyl methacrylate. The polymerisation was done by using group transfer polymerization (GTP) and free radical techniques. A multistep decomposition was observed in polymers prepared by free radical technique indicating the presence of weak linkages in the backbone. Copolymers prepared by GTP had fewer weak sites and degraded in single step by a random chain scission.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
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
In this work, we report a combined experimental and theoretical study on molecular and vibrational structure of 3-amino-5-hydroxypyrazole (3A5HP). The Fourier transform infrared and Fourier transform Raman spectra of 3A5HP were recorded in the solid phase. The molecular geometry and vibrational frequencies of 3A5HP in the ground state have been calculated by using the density functional method B3LYP with basis sets, 6-311++G(d,p), 6-311+G(3df,2p), 6-311+G(3df,2pd), CC-pVDZ, aug-CC-pVDZ and CC-pVTZ. The optimized geometrical parameters obtained by B3LYP show best agreement with the experimental values. The theoretical spectrograms for FT-IR and FT-Raman spectra of the title molecule have been constructed. 相似文献
Subgrid correlation of mixture fraction, Z, and progress variable, c, is investigated using direct numerical dimulation (DNS) data of a hydrogen lifted jet flame. Joint subgrid behaviour of these two scalars are obtained using a Gaussian-type filter for a broad range of filter sizes. A joint probability density function (JPDF) constructed using single-snapshot DNS data is compared qualitatively with that computed using two independent β-PDFs and a copula method. Strong negative correlation observed at different streamwise locations in the flame is captured well by the copula method. The subgrid contribution to the Z–c correlation becomes important if the filter is of the size of the laminar flame thickness or larger. A priori assessment for the filtered reaction rate using the flamelet approach with independent β-PDFs and correlated JPDF is then performed. Comparison with the DNS data shows that both models provide reasonably good results for a range of filter sizes. However, the reaction rate computed using copula JPDF is found to have a better agreement with the DNS data for large filter sizes because the subgrid Z–c correlation effect is included. 相似文献
Nb(2)O(5) as a new electron transport layer (ETL) was used for double junction polymer solar cells. The Nb(2)O(5) ETL was prepared by spin coating a Nb(2)O(5) sol-gel solution onto the active layer of the optical front subcell. The double junction devices using Nb(2)O(5) ETL exhibit an open circuit voltage (V(oc)) of 1.30 V, which is close to the sum of the s of the individual subcells. The current density-voltage (J-V) simulation showed that the double junction device performance using Nb(2)O(5) as ETL could be significantly increased by reducing the series resistance (R(se)) and matching the current densities of the individual subcells. 相似文献
Fluorine doped zinc oxide (FZO) films were fabricated from fresh and aged (4, 8, 12 and 16 days) starting solutions using a simplified and low cost spray pyrolysis technique. The X-ray diffraction study showed that the preferential orientation is along the (0 0 2) plane for all the films irrespective of the age of the solution. The crystallite size calculated using the Scherrer’s formula is comparatively smaller only for the film prepared from the starting solution having aging time 4 days which may be due to the efficient incorporation of fluorine atoms into the ZnO lattice. This phenomenon is confirmed by the minimum resistivity value (3.14 × 10−2 Ω cm) obtained in this particular case. The visible transmittance and the optical band gap values are found to be in the range of 63–83% and 3.20–3.31 eV, respectively. The optical transmittance is found to decrease gradually as the aging time of the solution increases and the optical band gap is found to be slightly higher in the case of the film prepared from the fourth day solution. The scanning electron microscopy results depicted that the microstructure of ZnO:F films are largely influenced by the aging of the starting solution. 相似文献
A green low-temperature deposition and crystallization method was developed to uniformly coat RuO2/TiO2 nanocomposite onto cotton fabrics for efficient solar photocatalysis. The sequential growth of anatase TiO2 and rutile RuO2 on the surface of the cotton was confirmed by XRD, Raman and XPS characterizations. After the deposition of RuO2, the optical properties of RuO2/TiO2/Cotton revealed better visible light absorption and higher charge mobility, and XPS spectra showed that the peaks of Ti 2p3/2 and O 1 s shifted towards the lower binding energies due to the interfacial charge transfer at the robust RuO2/TiO2 mediated with Ti–O–Ru bonding. The photocatalytic performances of the RuO2/TiO2/Cotton were evaluated towards the photodegradation of o-toluidine (o-TD), an aromatic amine widely used in the chemical industry. Compared with TiO2/Cotton, RuO2/TiO2/Cotton exhibited a remarkable improvement in the photocatalytic activity. The presence of RuO2 on the surface of TiO2/Cotton narrowed the band gap and improved the absorption of visible light. Moreover, the successful formation of a robust heterogeneous interface between TiO2 and RuO2 suppressed the charge carrier (e–/h+) recombination effectively. With the RuO2/TiO2 coating chemically bound to the cotton fibers, RuO2/TiO2/Cotton delivered long-term stability in photocatalytic activity and high mechanical durability even after 20 washing times. Our facile and scalable synthesis strategy paved a universal route to efficient immobilization of visible-light-responsible TiO2-based photocatalysts on the low-heat-resistant substrates for various applications.
The temperature dependent longitudinal and transverse Mossbauer elastic scattering fraction (MESF) of 47% disordered PVF2 have been computed using anisotropic dynamical model valid for polymer of any degree of crystallinity. The calculated values
show a marked anisotropy between the longitudinal and transverse fractions which can be easily observed. 相似文献