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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.
Textile wastewater is widely produced and its discharge without treatment contributes to environmental pollution. The adsorption process is a suitable and eco-friendly process due to its low initial ...cost, no formation of degradation products, operation simplicity, insensitivity to toxic compounds, and the possibility of removal from greatly diluted solutions. Orange seed (OS) powder, from which lipids were removed by hexane extraction, was evaluated as a bio-adsorbent to remove dyes from real textile wastewater. In the screening step, pH was a more significant variable (p-value < 0.05) than bio-adsorbent dosage, temperature, stirring speed, and process time. Moreover, under optimized conditions (pH = 2.6, 0.58 g/L from OS powder and 26 °C), more than 95% of the dye was removed from real textile wastewater. Additionally, the dye removal percentage was reduced by only 4% when the volume of textile wastewater was increased from 0.05 L to 10 L. Then, 96% turbidity was removed using a 3 µm tubular ceramic membrane at a pH of 11. Furthermore, the permeate flux through the membrane was kept constant for longer than was observed at low pH (<11). Therefore, the proposed process is an interesting option, due to the fact that orange seeds are currently not valorized and, combined with the membrane process, this could prove a suitable option for the treatment of real textile wastewater.
This work presents the synthesis and characterization of nanostructured cadmium sulfide thin films obtained by an ammonia-free chemical bath deposition process. Different levels of Cu ion doping were ...achieved by the ion exchange method of CdS at room temperature. The main objective was to control the energy band gap adjusting the copper concentration and to gather information about Cu-doped CdS thin films. Optical absorbance measurements were performed to obtain the band gap value through Tauc’s plot method. XPS measurements were used to obtain the copper and cadmium concentration. In addition, SEM micrographs were collected to obtain information about surface and structural arrangement on Cu-doped CdS thin films. It was also found that the exchange of cadmium by Cu-ions promoted the formation of a hexagonal crystalline structure, which was different than the initial pure cubic structure. Through optical characterization, it is possible to evaluate the impact of the metallic dopant on the band gap value, finding that it can be controlled by the percentage of added copper, which opens the possibility of applying this material to the development of electronic devices such as field effect transistors. In addition, a prototype of a MOS structure was fabricated employing both the undoped and the Cu-doped CdS thin film to corroborate its possible application as a field effect transistor.
Pine pitch canker (PPC), caused by Fusarium circinatum, affects Pinus species worldwide. Although no effective solutions have yet been found to control it, there is a growing interest in using ...biological control agents (BCA) such as Trichoderma to avoid the application of chemical‐based products. Using species with an increasing level of susceptibility to PPC (Pinus pinea, Pinus pinaster and Pinus radiata), this study aimed to evaluate the effect of Trichoderma viride pre‐inoculation on disease development, assessing several physiological and hormonal parameters. A 2‐week period elapsed between T. viride and F. circinatum inoculation. Sampling for each species was performed independently when at least 50% of the plants of one of the inoculated groups developed disease symptoms. Fusarium circinatum infection reduced water status and photosynthesis, but increased proline, abscisic acid and jasmonic acid concentrations in plants of P. radiata and P. pinaster with symptoms; while in P. pinea water relations were maintained and anthocyanin accumulation occurred in the presence of F. circinatum. In P. radiata, T. viride pre‐inoculation accelerated disease progression, with some PPC‐induced responses augmented (decreased water potential and photosynthesis; increased substomatal CO2 concentration) and novel changes not found in seedlings inoculated exclusively with F. circinatum (increased electrolyte leakage and salicylic acid; decreased relative water content). This suggests that T. viride may be initially recognized as an invading organism, subverting the plant defence mechanisms for successful root colonization. If seedlings are not allowed to recover from this state, pathogen infection may thus be facilitated, highlighting the importance of application timing in BCA strategies.
In this work, Ag
2
Se thin films were synthetized by a two-step technique at standard laboratory conditions. In the first step a silver hydrogen oxide carbonate thin film matrix was obtained by the ...chemical bath deposition technique. In the second step an ionic exchange between the matrix film and a new selenium ion solution was performed. The presence of silver and selenium atoms was detected by energy dispersive x-ray spectroscopy. From x-ray diffraction characterization, it was concluded there was an orthorhombic and polycrystalline structure for this material, Ag
2
Se. On the other hand, it was confirmed by transmission electron microscopy. The binding energies of silver and selenium were detected by x-ray photoelectron spectroscopy. From the ultraviolet–visible absorption spectra for the nanostructured Ag
2
Se thin film it was observed there was a blue shift in its bandgap, being 1.37 eV, meanwhile the reported bulk bandgap value is 0.15 eV.
In this work, the characterization of the enhanced structural and optical properties of the cadmium sulphide (CdS) nanostructured semiconductor associated with doping with metallic gold ions is ...presented. Thin films of good structural quality were obtained by chemical bath deposition and doped in-synthesis without the need for additional steps required. A controlled thickness of the thin films around 100 nm was confirmed by ellipsometry measurements. The binding energies of the CdS matrix and its interactions with the metallic gold ion were determined by X-ray photoelectron spectroscopy. The crystallinity and crystalline phase of the CdS matrix were studied by X-ray diffraction, obtaining that the predominant crystalline phase was Zinc blende. Furthermore, a change from monocrystalline to polycrystalline structure was observed in the gold-doped films, this behaviour was confirmed by TEM micrographs. In addition to the different levels of quantum confinement promoted by the transition metal. By Raman spectroscopy was confirmed that the predominant crystalline phase is zinc blende, additionally the vibrational Raman spectra allowed the analysis of the phononic interactions of the CdS binary where the Raman shift gives structural information and confirms the effects of quantum confinement. Optical properties were characterized by UV–Vis spectroscopy, which describes the effect of crystalline structural changes with shifts in the optical band gap energy of the evaluated samples with respect to the bulk CdS, related to the different levels of quantum confinement given by dopant metallic gold.
The recent use that has been given to bio-oil as an additive, in a commercial engine oil, raises the necessity to study its physical properties. The present study is aimed to obtain thermal ...properties of blends made with
Jatropha-Curcas
L. Oil, Crude, and Refined, at different concentrations using SAE40W oil (EO) as a lubricant base. By using photothermal techniques, thermal effusivity and diffusivity were obtained. The obtained results show that thermal effusivity increases from 455
Ws
1
/
2
·
m
-
2
·
K
-
1
to 520
Ws
1
/
2
·
m
-
2
·
K
-
1
as the percentage of additive increases as well, whereas thermal diffusivity values range from
7
×
10
-
8
m
2
·
s
-
1
to
10
×
10
-
8
m
2
·
s
-
1
. In the present study, four balls test was used in order to obtain friction coefficient and wear scar values for studied samples, the obtained results point out that in general refined
Jatropha-Curcas
L. oil presents smaller wear scars than the crude one.
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