BazTech - Yadda

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Raman Spectroscopy Analysis of the Morphology of Gold Nanoparticles Produced by Laser Ablation in Aqueous Proteinogenic Amino Acid for the Detection of Mercury in Water

Carbajal-Morán Hipólito

Journal of Ecological Engineering

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2023

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Vol. 24, nr 11

169--175

EN

The objective of the research was to analyze by Raman spectroscopy the morphology of gold nanoparticles generated by laser ablation in L-Cysteine of purity ≥ 97% dissolved in ultrapure water for the detection by color change of mercury dissolved in water. Three samples of 10 ml of ultrapure water were prepared with aggregation of 10 ul of L-Cysteine with concentrations of 1, 10 and 20 mM; the generation of the gold nanoparticles was by laser ablation with a wavelength λ = 1064 nm, energy of 60.28 mJ/p located at 30 cm from the convex lens generating ablation at 10 cm on a gold plate of dimensions 10×15 mm with thickness of 1 mm, for 30 min. The gold nanoparticles generated in these aqueous environments were characterized by Raman spectroscopy using a laser with a sensitivity of 785 nm with Raman Shift analysis range 860–3200 cm-1 and controlled power at 499 mW. The nanoparticles presented maximum peak resonance around Raman Shift 1164.96 cm-1 and 1288.06 cm-1. With the AuNPs + L-Cysteine sample with concentration of 10 mM, the author proceeded to the detection of Hg2+ prepared in 20 μl of ultrapure water at concentrations of 0.1, 5 and 10 μM; when adding 100 μl of AuNPs + L-Cysteine two peak absorbance spectra were obtained with different amplitudes observed by UV–Vis spectroscopy, indicating that Hg2+ decreased the repulsion of the negatively charged AuNPs, generating the visible color change for the three concentrations of Hg2+ with 25 minutes of agitation, turning intense purple for 10 μM of Hg2+; enabling the detection of mercury in water.

2

Analysis of the Influence of an XY Electronic Mechanism with UV-Vis Spectroscopy on the Production of Gold Nanoparticles by Laser Ablation for Applications in Environmental Nanosensing

Carbajal-Morán Hipólito, Márquez-Camarena Javier F., Ingaruca-Álvarez Ever F., Zárate-Quiñones Rosa H.

Journal of Ecological Engineering

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2023

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Vol. 24, nr 8

52--61

EN

The work consisted in analyzing the influence of an electronic positioning mechanism of an Au metal plate in the XY axes; to optimize the production of Au metal nanoparticles by laser ablation in sterile water samples as well as to obtain morphology and size required for environmental nanosensors. The positioning mechanism is constituted by two M35SP stepper motors of 5 V DC with a rotation angle of 7.5° per step; the one that generates the displacement for each axis of XY coordinates, controlled by an algorithm implemented in Arduino Nano ATmega328, being the driver of the stepper motors the H-bridge of the L298N module, with which it was possible to set the speed to 2 mm/s, which enabled to make the wear of the metal plate uniform in the process of generation of gold nanoparticles (AuNPs). With the pulsed laser generator with ablation frequency of 10 Hz and wavelengths of 532 nm and 1064 nm, the Au metal plate was irradiated for 10 min, 20 min and 30 min. AuNPs were generated in colloidal state both for the process with fixed position of the metal plate and for the process using the electronic mechanism of XY positioning; they were characterized by UV-Vis spectroscopy with range from 300 nm to 850 nm. It was found that the production of AuNPs with the Au plates mobilized by the mechanism under study, generates colloids of spherical AuNPs of smaller diameter, close to 10 nm, with an average reduction of 19% in relation to that generated with the fixed position plate; likewise, the concentration of the AuNPs increased by 20.40%; therefore, the influence of the XY positioning electronic mechanism was positive in the production of AuNPs with morphology and sizes suitable for use in environmental nanosensors.

3

Low Energy Trap with Light Emitting Diode for Increased Attraction of Phthorimaea operculella Zeller

Carbajal-Morán Hipólito, Márquez-Camarena Javier F., Galván-Maldonado Carlos A., Zárate-Quiñones Rosa H., Galván-Maldonado Alberto C.

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 6

270--275

EN

The Phthorimaea operculella Zeller moth is a pest that affects potato crops and is found mainly in the inter-Andean valleys of the highlands of Peru (Huancavelica). The objective of the research was to use the phenomenon of light generated by light-emitting diodes (LEDs) to attract the potato moth in storage. Every day at seven o’clock in the morning, the number of moths falling dead in the light trap on the water contained in the container was counted. Five LED lights with different light densities per square centimeter were tested for five nights with different frequencies: 3.125 Hz, 12.5 Hz, 50 Hz, 200 Hz and 400 Hz. Every five nights the operating current of the LEDs was changed: 5 mA, 10 mA and 15 mA. Every fifteen nights the color of the LEDs was changed, according to the following sequence: white, blue, green, yellow and red; the color that attracted the most was white light, while the one with the least attraction was red light. The white light trap using the 64 LED array attracted 38.73% of moths and consumed a total of 43 W of energy in seven days, so it is considered low energy consumption.

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Evaluation of Normalized Difference Vegetation Index by Remote Sensing with Landsat Satellites in the Tayacaja Valley in the Central Andes of Peru

Carbajal-Morán Hipólito, Márquez-Camarena Javier F., Galván-Maldonado Carlos A., Zárate-Quiñones Rosa H., Galván-Maldonado Alberto C., Muñoz-De la Torre Rossibel J.

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 7

208--215

EN

The research sought to evaluate the normalized difference vegetation index (NDVI) of the study area located in the province of Tayacaja, which includes the districts of Acraquia, Ahuaycha, Pampas and Daniel Hernández, which is part of the central Andes of Peru. The data were collected in low water seasons with a longitudinal cut of 30 years with one sample per year, starting in 1993 until 2022; these samples corresponded to the month of August of each year. The images were extracted from maps from Landsat satellite databases, which were filtered for low cloud cover to avoid interference with the images. Maps from 1993 to 2012 were obtained from Landsat 5 satellite, while from 2013 to 2022 data were obtained from Landsat 8 satellite. The normalized difference vegetation index was determined using Quantum GIS based on the red and near infrared maps; being the minimum NDVI value obtained -0.18, which corresponds to the aquatic body of the Upamayu River that crosses from west to east the study area; while the highest NDVI obtained was 0.79 indicating a greater vegetation cover constituted by mainly eucalyptus plants. The mean NDVI of the 30 years is close to 0.21; this is an indicator that the vegetation is scarce and that it is decreasing mainly due to population growth.

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Influence of Gold Nanoparticles on the Photocatalytic Action of Titanium Dioxide in Physical-Chemical Parameters of Greywater

Carbajal-Morán Hipólito, Márquez-Camarena Javier F., Galván-Maldonado Carlos A.

Journal of Ecological Engineering

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2022

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Vol. 23, nr 1

182--192

EN

The objective of the work was to evaluate the influence of gold nanoparticles, obtained by laser ablation, on the photocatalytic action of titanium dioxide in the improvement of the physical-chemical parameters of domestic greywater, with visualization by means of a PLC. The YAG laser equipment was used for the production of spherical gold nanoparticles, whereas the Raman spectroscope allowed characterizing the different particles contained in aqueous solutions. The solar photoreactor programmable and viewable from PLC with connection to sensors allowed determining the variations of the pH, EC, DO and FCL parameters. The work consisted of a control group (greywater + titanium dioxide) and an experimental group (greywater + titanium dioxide + gold nanoparticles). The titanium dioxide doses for both groups were 0.5 mg/L and the gold nanoparticles were 0.20 ml per liter of greywater only for the control group. The experiments were carried out on sunny days with the exposure periods of 30 and 60 minutes around solar noon with an average UV index of 13.35. Once the experiments were carried out, it was determined that the pH improved by 5.30%, EC by 3.03%, DO by 29.3% and FCL by 43.71%, so that the gold nanoparticles dissolved in the aqueous solution of titanium dioxide with greywater positively influenced the improvement of the photocatalytic action of titanium dioxide in the physical-chemical parameters of greywater.

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Functionalization of Gold Nanoparticles for the Detection of Heavy Metals in Contaminated Water Samples in the Province of Tayacaja

Carbajal-Morán Hipólito, Rivera-Esteban Jesús M., Aldama-Reyna Claver W., Mejía-Uriarte Elsi V.

Journal of Ecological Engineering

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2022

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Vol. 23, nr 9

88--99

EN

The work consisted in functionalizing gold nanoparticles to analytically detect heavy metals in contaminated water; in Tayacaja-Huancavelica-Peru, using physical method of laser ablation. The 450 mJ/p Nd:YAG was used as a pulsed laser generator for the production of colloids from AuNPs by the top-down approach; the target was a 1 cm x 1.5 cm high purity gold metallic plate with a thickness of 1 mm, inside a 20 ml cuvette of deionized water, containing 5 ml of L-Cysteine ≥ 75% purity. Nanoparticle colloids were characterized by UV-Vis spectroscopy from 200 to 1160 nm range. Using a convex lens, the gold metal plate was ablated by the laser equipment, located 10 cm from the focus; with λ = 1064 nm and λ = 532 nm with energy equivalent to 60.28 mJ/p and 32.99 mJ/p respectively, with a ratio of 2 Hz, for 30 and 60 min. All the samples produced were subjected to the dispersion process by sonication at 40 KHz for one hour. The functionalized nanoparticles presented a resonance displacement of the maximum wavelength peak with respect to the reference at approximately 22.51 nm; consequently, the increase in diameter occurred at 52.10 nm. The sensitive capacity of the functionalized nanoparticles was verified for different concentrations of analytes in water, made up of divalent heavy metal ions Cd2+, Pb2+, and trivalent nonmetal As3+. At a concentration greater than 500 uM, the color of the functionalized nanoparticles turned bluish, due to the presence of positive ions. Therefore, it was stated that the functionalized nanoparticles enable the detection of heavy metals in water by color variation.

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Solar Dryer with Electronic PID Controller for Dry Potato Production

Herrera-Morales Javier A., Carbajal-Morán Hipólito, Almidón-Elescano Ángel

Ecological Engineering & Environmental Technology

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2022

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Vol. 23, iss. 1

223--229

EN

The objective of the research was to determine the amount of moist extractable matter from the precooked potato dough with the cut in the shape of sticks and the acceleration of the subtraction of moisture from the matter to be dried inside the solar dryer, controlling the flow of dry air entering the collector through six fans. The temperature and relative humidity in the dryer vary with the flow of air that enters the interior of the dryer and by the heat of the brass generated by the exposure of the extraction chamber to radiation from the Sun from 9:00 am. to 5:00 pm. The temperature and relative humidity values detected by the DHT 22 sensor were processed by the Arduino based microcontroller that has embedded the PID control program, whose outputs acted on the fans and heaters, fed with conventional energy, with respect to the setpoints of temperature 36.5 °C and relative humidity 33%. 26 temperature and relative humidity samples were taken during the day, inside the solar dryer chamber with electronic PID controller. As a result, an average controlled temperature of 36.36 °C and relative humidity of 33.115% were obtained in the dryer chamber, allowing the extraction of 73.16% of the weight of the wet matter from the precooked potato. Achieving, dry potato weighing 26.84% of the initial mass, in a drying time of 8 hours.

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Gray Water Recovery System Model by Solar Photocatalysis with TiO2 Nanoparticles for Crop Irrigation

Carbajal-Morán Hipólito, Zárate-Quiñones Rosa H., Márquez-Camarena Javier F.

Journal of Ecological Engineering

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2021

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Vol. 22, nr 4

78--87

EN

The objective of the study was to establish the configuration of the system model to allow the effective recovery of gray water by solar photocatalysis with TiO2 nanoparticles for irrigation of crops. A programmable solar photoreactor based on an S7 1500 PLC and online measurement sensors were used as materials. The inductive method was used to analyze the samples and the deductive method to determine the water quality. The research design used was experimental based on the response surface methodology (MSR) with 20 experiments, 6 of which were central experiments and 6 were axial experiments; these experiments were carried out on sunny days. As a result of the research, a gray water recovery model was obtained, part of this being an electronic system with a programmable photocatalyst, which allowed the development of the experiments. It was concluded that with a solar UV index of 12.21, a dose of titanium dioxide (TiO2) nanoparticles 1.973 g/L and with an exposure period of 60.041 minutes of the solar photocatalyst to UV radiation on sunny days, gray water was recovered in 90% with a confidence level of 95% and a significance α = 0.05, which translates into excellent quality according to the water quality index established in Peru (ICA-PE).