Josefina Vergara - Academia.edu (original) (raw)

Papers by Josefina Vergara

Water Quality - Factors and Impacts, 2022

The mobility of heavy metals in aquatic environments, impacted by discharges from mining waste, i... more The mobility of heavy metals in aquatic environments, impacted by discharges from mining waste, is one of the major processes causing metal pollution mainly by arsenic (As), cadmium (Cd), lead (Pb), zinc (Zn) and iron (Fe), which could be risky for biota and human health. The heavy metals contained in mining waste constituted by large amounts of sulfides can reach the aquatic compartments by acid mine drainage and runoff and eventually become deposited in sediments and associated with colloidal material, being this one of the main reservoirs and ways of transport. However, the mobility of heavy metal is influenced by their specific chemical properties and undergo several physicochemical phenomena as sorption, oxidation–reduction, hydrolysis and this can be influenced by water flow, the size and composition of geological material. Hence, this work aims to review the processes and mechanism involved in the fate and transport of heavy metals from mining-waste to aquatic compartments an...

Atmosphere, 2022

Tropospheric ozone is an obligatorily-regulated pollutant, to ensure health protection and better... more Tropospheric ozone is an obligatorily-regulated pollutant, to ensure health protection and better air quality. Most countries have established maximum permissible limits (MPL) equal to 0.06 or 0.070 ppmv, but these could be insufficient considering the strictest MPL of the World Health Organization (WHO) guidelines. Such concentrations may still cause health damage to some groups of the population in urban areas. Additionally, the mean value is the principal statistical parameter for monitoring air pollution. This factor may be hiding critical ozone concentrations for public health. This work examines the mean and maximum ozone based on a multi-temporal analysis, to explore the use of a maximum average value as an air quality standard. The mean ozone had a remarkably stationary contrast; while, the maximum ozone emphasized a semi-permanent state of high pollution over the year. Diurnal variation highlights the differences of frequency between the mean and maximum ozone above any MPL...

Separations, 2022

This study evaluated the distribution and potential estrogenic risk of the presence of bisphenol ... more This study evaluated the distribution and potential estrogenic risk of the presence of bisphenol A (BPA), 4-nonylphenol (4NP), naproxen (NPX), ibuprofen (IBU), 17-β-estradiol (E2) and 17-α-ethinylestradiol (EE2) in water and sediments of the Apatlaco river micro-basin (Morelos, Mexico). The concentration of the determined compounds ranged between 1 ng·L−1).

South Florida Journal of Development, 2021

This study was carried out from September to December 2012 and January-February 2013, in the Facu... more This study was carried out from September to December 2012 and January-February 2013, in the Faculty of Chemical Sciences of the Autonomous University of Coahuila, in total 13 samples were taken. On that period, dry weather predominated, with an average temperature of 17.0 °C, relative humidity of 52.0% and wind speed of 3.5 m s-1. The mean concentration for PM2.5 was 36.0 μg m-3. The most abundant metal in PM2.5 was Fe, with an average concentration of 1386.4 ng m-3 and the lowest concentration was obtained for Cd with 4.1 ng m-3. On the other hand, within the ionic species the most abundant were sulfates (3569.0 ng m-3), while ammonium was the least abundant species (490.9 ng m-3). The ion balance indicated that during the study period the suspended particles had acidic characteristics, which means that the amount of cations was not sufficient to neutralize the sulfates, nitrates and chlorides. Finally, the risk assessment indicates that of heavy metal in the PM2.5, represent a po...

DESALINATION AND WATER TREATMENT, 2021

The wastewater generated by the textile industry causes serious problems for ecosystems when disc... more The wastewater generated by the textile industry causes serious problems for ecosystems when discarded without effective treatment. Samples of water contaminated with the Direct Orange 39 dye were treated by plasma discharge generated at atmospheric pressure for 150 min. In this study, the initial concentration of the dye was 1.0 mM with an initial volume of 250 mL. Moreover, iron filings (Fe 2+) were used as a catalyst. Reduction of the dye concentration in the samples was possible as a function of treatment time. This was verified by the absorbance spectrum in the UV-vis range. During treatment, every 15 min, we monitored the electric current, voltage, temperature of the water containing the dye, volume, pH, electrical conductivity, absorbance, concentrations of nitrates and nitrites, total organic carbon (TOC), chemical oxygen demand (COD), and the optical emission spectrum of the plasma and determined the dye concentration, discoloration factor, percentage of mineralization, and G 50 (which expresses the amount of energy required to eliminate 50% of the pollutant), and electrical cost. Results showed that the efficiency of the dye degradation by plasma is a function of treatment time, and we obtained the removal of 50% of the colorant in 34 min and 94.2% in 120 min; additionally, COD was at 98.6%, the TOC was at 98.7%, and the percentage of mineralization was at 98.5% after 150 min of treatment. The maximum concentrations of nitrates and nitrites were 214 and 32 mg/L, respectively, after 150 min. From the optical spectrum of plasma emission, different species were identified (e.g., OH, N 2 , Na, H α , and H β). The G 50 value was 0.825 g/kWh, and the electrical cost calculated for the treatment of 1 m 3 of water with this colorant using plasma was $3.20 after 150 min of treatment.

Atmosphere, 2020

Atmospheric particles with an aerodynamic diameter less than or equal to 2.5 micrometers (PM2.5) ... more Atmospheric particles with an aerodynamic diameter less than or equal to 2.5 micrometers (PM2.5) were collected at two sites located in the urban area of the city of Cuernavaca (Morelos) during a season when a large number of forest fires occurred. Three dicarboxylic acids (malonic, glutaric and succinic) and levoglucosan were analyzed by liquid chromatography coupled with mass spectrometry (ESI-Q-TOF) and soluble potassium (K+) was analyzed by ion chromatography. The concentration of PM2.5 increased on the days when the highest number of forest fires occurred. A strong correlation was observed between levoglucosan and K+, confirming the hypothesis that both are tracers of biomass burning (r = 0.57, p < 0.05). Levoglucosan (average 367.6 ng m−3, Site 2) was the most abundant compound, followed by succinic acid (average 101.7 ng m−3, Site 2), glutaric acid (average 63.2 ng m−3, Site 2), and malonic acid (average 46.9 ng m−3, Site 2), respectively. The ratio of C3/C4 concentrations...

Water, 2019

In this study, two hormones 17β-estradiol (E2) and 17α-ethynylestradiol (EE2), and three phenolic... more In this study, two hormones 17β-estradiol (E2) and 17α-ethynylestradiol (EE2), and three phenolic compounds, bisphenol A (BPA), 4-N-nonylphenol (4-NP) and 4-tert-octylphenol (4-t-OP), were determined in surface water in the Cuautla River at the State of Morelos during the dry-season in Mexico. The endocrine disrupting compounds (EDCs) were extracted from water samples using solid-phase extraction (SPE) with end-capped C18, and then the extracts were chemically derivatized to TMS (trimethylsylane)-compounds and analyzed by gas chromatography coupled to mass spectrometry (GCMS). The most abundant compound was BPA (22.46 ± 30.17 ng L−1), followed by 4-t-OP (11.24 ± 11.76 ng L−1), 4-NP (7.53 ± 14.88 ng L−1), EE2 (2.37 ± 4.36 ng L−1) and E2 (0.97 ± 1.82 ng L−1). The residual amounts of target compounds could either reach stream surface water from direct domestic wastewater discharges, conventional wastewater treatment plant or can be a result from the use of agrochemicals in crop areas. ...

Separations, 2018

Bisphenol A (BPA), 4-nonylphenol (4NP), estradiol (E 2), and ethinylestradiol (EE 2) are consider... more Bisphenol A (BPA), 4-nonylphenol (4NP), estradiol (E 2), and ethinylestradiol (EE 2) are considered as endocrine disruptors or mutagens. These compounds are commonly called endocrine disrupter chemicals (EDCs). BPA and 4NP are widely used as plastic additives, lacquers, resins, or surfactants, while E 2 is one of the predominant female sex hormones during the reproductive years, and EE 2 is an estrogen derived from estradiol, used in the production of contraceptive pills. All of these can be usually found in wastewater. In Mexico, it is common for water from rivers, lakes, and canyons to be reused for different purposes. Unfortunately, there is little information on the concentration of many of the pollutants present in such bodies of water. To determine the presence of these compounds in samples of wastewater in the Apatlaco River, an accurate and reproducible method was developed by coupling gas chromatography to mass spectrometry (GC-MS). A solid-phase extraction with Chromabond RP-18 cartridges was carried out, and the elution was performed with an acetone/methanol mixture. After isolation, the solvent was removed and a silylation step was carried out using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). Recoveries for spiked samples were between 71.8% and 111.0%. The instrumental limits of detection (IDL) ranged between 24.7 and 37.0 ng mL −1. In total, 16 samples were taken in 2015 at the microbasin of the Apatlaco River, located in the state of Morelos. The maximum concentrations found were 4NP (85.5 ng mL −1), BPA (174.6 ng mL −1), E 2 103.6 (ng mL −1), and EE 2 (624.3 ng mL −1).

DESALINATION AND WATER TREATMENT, 2019

In this study, the effect of maintaining the same initial chemical and physical conditions in the... more In this study, the effect of maintaining the same initial chemical and physical conditions in the mineralization process, (decomposition of organic pollutants in aqueous solutions to CO 2 , mineral salts and water) was evaluated for 2 azo-type dyes (N=N) using a cold plasma as agent precursor to the mechanism of elimination of pollutants in water. This paper reports the treatment of water with Acid Black 52 (AB52) and Acid Black 210 (AB210), using as a reaction accelerator iron filing (analytical grade) (Fe 2+). The kinetics of the reaction was determined by UV/VIS spectrophotometry, at the beginning and during the treatment of the samples the total organic carbon (TOC) and chemical oxygen demand (COD) value was determined. The discoloration values in 180 min are greater than 95% and the values of TOC and COD decrease, more than 90% depending upon the time of treatment. In addition, the optical emission spectrum of the plasma was obtained to determine the species present in the ionization processes of the corona discharge. The energy yield value was calculated in terms of G 50 , these results provide information for the subsequent application of this process to degradation of organic compounds.

IEEE Transactions on Plasma Science, 2017

The variations in the physical and chemical parameters involved in the degradation of dye Acid Bl... more The variations in the physical and chemical parameters involved in the degradation of dye Acid Black 52 (AB52) using plasma were analyzed. The plasma, or electrical discharge, was generated in the gas-liquid interface at atmospheric pressure using a dc power supply. The system configuration comprised two tungsten electrodes: the cathode is immersed in the solution while the anode is fixed above the surface with a gap of 5 mm, where the plasma is generated. The absorbance, total organic carbon, chemical oxygen demand, pH variation, electrical conductivity, optical emission spectrum, and the change in volume and temperature were measured for each sample as a function of treatment time. Index Terms-Absorbance, atmospheric pressure plasma, chemical oxygen demand (COD), optical emission spectroscopy (OES), textile dye, total organic carbon (TOC). I. INTRODUCTION W ATER pollution is an important environmental problem globally; therefore, techniques for the treatment of contaminated water must be developed. Recent studies based on techniques such as ultraviolet (UV) photolysis, Fenton process, direct ozonation, ultrasonification, and nonthermal plasma have shown the possibility of degrading pollutants in wastewater [1]-[4]. However, these techniques produce ozone and consume large amounts of energy because of their low efficiency [5]. Dyes are widely used in the textile industry, and are classified based on their chemical structure. The Color index assigns to dyes known has 25 structural classes according to the type of chemical, the most important structure are: azo dyes, anthraquinone dyes, and phthalocyanines; all dyes, except natural ones, are environment pollutants.

Revista Mexicana de Ingeniería Química, 2019

Modelado de la biodegradación en biorreactores de lodos de hidrocarburos totales del petróleo int... more Modelado de la biodegradación en biorreactores de lodos de hidrocarburos totales del petróleo intemperizados en suelos y sedimentos (Biodegradation modeling of sludge bioreactors of total petroleum hydrocarbons weathering in soil and sediments)

DESALINATION AND WATER TREATMENT, 2019

Hydrocarbon Pollution and its Effect on the Environment, 2018

Polycyclic aromatic hydrocarbons (PAHs) are formed in natural processes during combustion of biom... more Polycyclic aromatic hydrocarbons (PAHs) are formed in natural processes during combustion of biomass (e.g., forest fires) and by anthropogenic activities at high temperatures. In according with the suggestion the major sources of PAHs in the environment. The main sources of PAHs come basically from heat and power generation (e.g., coal, gas, wood, and oil), industrial processes (e.g., coke production), refuse burning and vehicle emissions. Human exposure to airborne PAHs can result from these processes, as well as from emissions from other sources, such as cooking, smoking, and materials containing PAHs (e.g., petroleum products and fuels). The potential serious health effects resulting from acute and chronic human exposure to PAHs are of concern. For this reason, the identification and quantification of PAHs in airborne particles have been a real challenge, given the multiple impacts that these substances represent for human health. In the last decade, multiple technological developments have been implemented, ranging from sampling systems, extraction and analysis of these compounds with the aim of obtaining more accurate and reliable results. This chapter was prepared to describe and to assess the state of the art about the evolution and application of sampling, extraction and analysis methodologies for the determination of PAHs in airborne particles.

IEEE Transactions on Plasma Science, 2015

In this paper, the addition of Ar to H 2 is experimentally investigated. This paper primarily aim... more In this paper, the addition of Ar to H 2 is experimentally investigated. This paper primarily aims to observe the effects that this addition has on the intensity of hydrogen emission lines in a glow discharge mixture. The total pressure was 3 torr, at a power level of 3.9 W. Optical emission spectroscopy was used for plasma characterization, and the principal species observed were H γ (434 nm), H β (486.1 nm), H α (656.3 nm), and H 2 (603.1 nm), and Ar I (750.5 nm), Ar I (763.5 nm), and Ar I (811.6 nm). The electron temperature and ion density were determined by a double Langmuir probe. The electron temperature was found to be in the range of 2.5-6.5 eV, and the ion concentration was on the order of 10 9 cm −3. Index Terms-Balmer lines, glow discharge, low pressure plasma, low temperature plasma, optical emission spectroscopy (OES) of cold plasma.

Solar Energy Materials and Solar Cells, 2011

Fe III supported on ceria as an effective catalyst for oxidation was prepared and used for the de... more Fe III supported on ceria as an effective catalyst for oxidation was prepared and used for the degradation of basic orange 2 azo textile dye (BO2). BO2 was chosen as a model pollutant and the catalytic oxidation was carried out in a batch reactor using hydrogen peroxide as the oxidant at pH 3. The influent factors on BO2 oxidation, such as catalyst dosage, H 2 O 2 concentration, and BO2 concentration were studied by considering the BO2 conversion and chemical oxygen demand (COD) removal. The Fe III-ceria catalyst showed a high catalytic activity for the oxidation of BO2 in aqueous solution. It was observed that the solution became colorless after 5 h of oxidation and over 90% COD removal was achieved with all the Fe III-ceria catalysts used under dark conditions in the catalytic oxidation system. The catalytic removal of BO2 during BO2 oxidation was improved under solar radiation, which notably increased the BO2 degradation rate. Consecutive BO2 oxidation cycles carried out with the same Fe III-ceria catalyst and untreated fresh dyestuff solution showed that the catalyst had good stability and good degradation performance, thus evidencing the possibility of being used in continuous processes. This study showed that the Fe III-ceria catalytic oxidation process is an efficient method for the treatment of BO2 aqueous solutions.

American Journal of Environmental Sciences, 2008

The degradation of water soluble corn oil wastes was carried out by Fenton reaction and also unde... more The degradation of water soluble corn oil wastes was carried out by Fenton reaction and also under mildly basic media in the presence of oxidants, such as hydrogen peroxide and persulfate, assisted with solar light. The degradation efficiency was obtained by analysis of chemical oxygen demand, carbon dioxide and gas chromatography. Over 90% of both chemical oxygen demand abatement and carbon dioxide recovery was accomplished by Fenton reaction. The presence of oxidants during the photodegradation resulted in high chemical oxygen demand abatement of the oil waste with the disappearance of the majority of the initial fatty acids present in the oil waste before treatment.

La industria textil genera grandes cantidades de agua residual contaminadas principalmente por co... more La industria textil genera grandes cantidades de agua residual contaminadas principalmente por colorantes los cuales pueden ser toxicos y persistentes. Este presenta un problema importante debido a la gran cantidad de agua residual proveniente de la industria textil, poniendo en peligro la calidad del agua a donde esta es descargada, la vida acuatica y la salud de los seres humanos. Se ha demostrado que la aplicacion de los procesos de oxidacion avanzada (PAOs) tiene un papel importante en la degradacion de estos contaminantes. En el presente proyecto se trabajo con los procesos Fenton y foto Fenton para la degradacion del colorante negro acido 52, colorante soluble en agua y usado para tenir fibras poliamida como el nylon. Ambos procesos presentan buenos resultados a nivel experimental, se ha demostrado que remueven mas del 90 % de la materia organica presente en el agua bajo tiempos de accion desde 30 a 120 minutos, lo que los convierte en procesos eficientes.

En la industria textil se producen grandes cantidades de agua residual con colorantes que represe... more En la industria textil se producen grandes cantidades de agua residual con colorantes que representan un gran problema ambiental, es por ello que se deben utilizar Proceso de Oxidacion Avanzada para su degradacion. Los reactivos utilizados en la degradacion del colorante Negro acido 52 fueron de FeSO4 a 50 mM y H2SO4 a 0.1 M, CuSO4 50mM y Al2SO4 50mM y agua destilada. El colorante textil fue proporcionado por una industria textil de la Region Oriente de Estado de Morelos. Se empleo un Plasma No Termico producido por corriente directa. La implementacion del plasma no termico se probo con distintas concentraciones del reactivo FeSO4 y variando el tiempo de aplicacion del plasma para determinar la concentracion y el tiempo optimo de degradacion; a su vez se probaron otros reactivos como Al2(SO4)3 y CuSO4 para comprobar su efecto en la oxidacion y degradacion del colorante Negro acido 52 (NA52). Las pruebas se realizaron en un reactor BACH de 250 ml a un pH de 2.4-2.6. La Remocion optim...

Water Quality - Factors and Impacts, 2022

The mobility of heavy metals in aquatic environments, impacted by discharges from mining waste, i... more The mobility of heavy metals in aquatic environments, impacted by discharges from mining waste, is one of the major processes causing metal pollution mainly by arsenic (As), cadmium (Cd), lead (Pb), zinc (Zn) and iron (Fe), which could be risky for biota and human health. The heavy metals contained in mining waste constituted by large amounts of sulfides can reach the aquatic compartments by acid mine drainage and runoff and eventually become deposited in sediments and associated with colloidal material, being this one of the main reservoirs and ways of transport. However, the mobility of heavy metal is influenced by their specific chemical properties and undergo several physicochemical phenomena as sorption, oxidation–reduction, hydrolysis and this can be influenced by water flow, the size and composition of geological material. Hence, this work aims to review the processes and mechanism involved in the fate and transport of heavy metals from mining-waste to aquatic compartments an...

Atmosphere, 2022

Tropospheric ozone is an obligatorily-regulated pollutant, to ensure health protection and better... more Tropospheric ozone is an obligatorily-regulated pollutant, to ensure health protection and better air quality. Most countries have established maximum permissible limits (MPL) equal to 0.06 or 0.070 ppmv, but these could be insufficient considering the strictest MPL of the World Health Organization (WHO) guidelines. Such concentrations may still cause health damage to some groups of the population in urban areas. Additionally, the mean value is the principal statistical parameter for monitoring air pollution. This factor may be hiding critical ozone concentrations for public health. This work examines the mean and maximum ozone based on a multi-temporal analysis, to explore the use of a maximum average value as an air quality standard. The mean ozone had a remarkably stationary contrast; while, the maximum ozone emphasized a semi-permanent state of high pollution over the year. Diurnal variation highlights the differences of frequency between the mean and maximum ozone above any MPL...

Separations, 2022

This study evaluated the distribution and potential estrogenic risk of the presence of bisphenol ... more This study evaluated the distribution and potential estrogenic risk of the presence of bisphenol A (BPA), 4-nonylphenol (4NP), naproxen (NPX), ibuprofen (IBU), 17-β-estradiol (E2) and 17-α-ethinylestradiol (EE2) in water and sediments of the Apatlaco river micro-basin (Morelos, Mexico). The concentration of the determined compounds ranged between 1 ng·L−1).

South Florida Journal of Development, 2021

This study was carried out from September to December 2012 and January-February 2013, in the Facu... more This study was carried out from September to December 2012 and January-February 2013, in the Faculty of Chemical Sciences of the Autonomous University of Coahuila, in total 13 samples were taken. On that period, dry weather predominated, with an average temperature of 17.0 °C, relative humidity of 52.0% and wind speed of 3.5 m s-1. The mean concentration for PM2.5 was 36.0 μg m-3. The most abundant metal in PM2.5 was Fe, with an average concentration of 1386.4 ng m-3 and the lowest concentration was obtained for Cd with 4.1 ng m-3. On the other hand, within the ionic species the most abundant were sulfates (3569.0 ng m-3), while ammonium was the least abundant species (490.9 ng m-3). The ion balance indicated that during the study period the suspended particles had acidic characteristics, which means that the amount of cations was not sufficient to neutralize the sulfates, nitrates and chlorides. Finally, the risk assessment indicates that of heavy metal in the PM2.5, represent a po...

DESALINATION AND WATER TREATMENT, 2021

The wastewater generated by the textile industry causes serious problems for ecosystems when disc... more The wastewater generated by the textile industry causes serious problems for ecosystems when discarded without effective treatment. Samples of water contaminated with the Direct Orange 39 dye were treated by plasma discharge generated at atmospheric pressure for 150 min. In this study, the initial concentration of the dye was 1.0 mM with an initial volume of 250 mL. Moreover, iron filings (Fe 2+) were used as a catalyst. Reduction of the dye concentration in the samples was possible as a function of treatment time. This was verified by the absorbance spectrum in the UV-vis range. During treatment, every 15 min, we monitored the electric current, voltage, temperature of the water containing the dye, volume, pH, electrical conductivity, absorbance, concentrations of nitrates and nitrites, total organic carbon (TOC), chemical oxygen demand (COD), and the optical emission spectrum of the plasma and determined the dye concentration, discoloration factor, percentage of mineralization, and G 50 (which expresses the amount of energy required to eliminate 50% of the pollutant), and electrical cost. Results showed that the efficiency of the dye degradation by plasma is a function of treatment time, and we obtained the removal of 50% of the colorant in 34 min and 94.2% in 120 min; additionally, COD was at 98.6%, the TOC was at 98.7%, and the percentage of mineralization was at 98.5% after 150 min of treatment. The maximum concentrations of nitrates and nitrites were 214 and 32 mg/L, respectively, after 150 min. From the optical spectrum of plasma emission, different species were identified (e.g., OH, N 2 , Na, H α , and H β). The G 50 value was 0.825 g/kWh, and the electrical cost calculated for the treatment of 1 m 3 of water with this colorant using plasma was $3.20 after 150 min of treatment.

Atmosphere, 2020

Atmospheric particles with an aerodynamic diameter less than or equal to 2.5 micrometers (PM2.5) ... more Atmospheric particles with an aerodynamic diameter less than or equal to 2.5 micrometers (PM2.5) were collected at two sites located in the urban area of the city of Cuernavaca (Morelos) during a season when a large number of forest fires occurred. Three dicarboxylic acids (malonic, glutaric and succinic) and levoglucosan were analyzed by liquid chromatography coupled with mass spectrometry (ESI-Q-TOF) and soluble potassium (K+) was analyzed by ion chromatography. The concentration of PM2.5 increased on the days when the highest number of forest fires occurred. A strong correlation was observed between levoglucosan and K+, confirming the hypothesis that both are tracers of biomass burning (r = 0.57, p < 0.05). Levoglucosan (average 367.6 ng m−3, Site 2) was the most abundant compound, followed by succinic acid (average 101.7 ng m−3, Site 2), glutaric acid (average 63.2 ng m−3, Site 2), and malonic acid (average 46.9 ng m−3, Site 2), respectively. The ratio of C3/C4 concentrations...

Water, 2019

In this study, two hormones 17β-estradiol (E2) and 17α-ethynylestradiol (EE2), and three phenolic... more In this study, two hormones 17β-estradiol (E2) and 17α-ethynylestradiol (EE2), and three phenolic compounds, bisphenol A (BPA), 4-N-nonylphenol (4-NP) and 4-tert-octylphenol (4-t-OP), were determined in surface water in the Cuautla River at the State of Morelos during the dry-season in Mexico. The endocrine disrupting compounds (EDCs) were extracted from water samples using solid-phase extraction (SPE) with end-capped C18, and then the extracts were chemically derivatized to TMS (trimethylsylane)-compounds and analyzed by gas chromatography coupled to mass spectrometry (GCMS). The most abundant compound was BPA (22.46 ± 30.17 ng L−1), followed by 4-t-OP (11.24 ± 11.76 ng L−1), 4-NP (7.53 ± 14.88 ng L−1), EE2 (2.37 ± 4.36 ng L−1) and E2 (0.97 ± 1.82 ng L−1). The residual amounts of target compounds could either reach stream surface water from direct domestic wastewater discharges, conventional wastewater treatment plant or can be a result from the use of agrochemicals in crop areas. ...

Separations, 2018

Bisphenol A (BPA), 4-nonylphenol (4NP), estradiol (E 2), and ethinylestradiol (EE 2) are consider... more Bisphenol A (BPA), 4-nonylphenol (4NP), estradiol (E 2), and ethinylestradiol (EE 2) are considered as endocrine disruptors or mutagens. These compounds are commonly called endocrine disrupter chemicals (EDCs). BPA and 4NP are widely used as plastic additives, lacquers, resins, or surfactants, while E 2 is one of the predominant female sex hormones during the reproductive years, and EE 2 is an estrogen derived from estradiol, used in the production of contraceptive pills. All of these can be usually found in wastewater. In Mexico, it is common for water from rivers, lakes, and canyons to be reused for different purposes. Unfortunately, there is little information on the concentration of many of the pollutants present in such bodies of water. To determine the presence of these compounds in samples of wastewater in the Apatlaco River, an accurate and reproducible method was developed by coupling gas chromatography to mass spectrometry (GC-MS). A solid-phase extraction with Chromabond RP-18 cartridges was carried out, and the elution was performed with an acetone/methanol mixture. After isolation, the solvent was removed and a silylation step was carried out using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). Recoveries for spiked samples were between 71.8% and 111.0%. The instrumental limits of detection (IDL) ranged between 24.7 and 37.0 ng mL −1. In total, 16 samples were taken in 2015 at the microbasin of the Apatlaco River, located in the state of Morelos. The maximum concentrations found were 4NP (85.5 ng mL −1), BPA (174.6 ng mL −1), E 2 103.6 (ng mL −1), and EE 2 (624.3 ng mL −1).

DESALINATION AND WATER TREATMENT, 2019

In this study, the effect of maintaining the same initial chemical and physical conditions in the... more In this study, the effect of maintaining the same initial chemical and physical conditions in the mineralization process, (decomposition of organic pollutants in aqueous solutions to CO 2 , mineral salts and water) was evaluated for 2 azo-type dyes (N=N) using a cold plasma as agent precursor to the mechanism of elimination of pollutants in water. This paper reports the treatment of water with Acid Black 52 (AB52) and Acid Black 210 (AB210), using as a reaction accelerator iron filing (analytical grade) (Fe 2+). The kinetics of the reaction was determined by UV/VIS spectrophotometry, at the beginning and during the treatment of the samples the total organic carbon (TOC) and chemical oxygen demand (COD) value was determined. The discoloration values in 180 min are greater than 95% and the values of TOC and COD decrease, more than 90% depending upon the time of treatment. In addition, the optical emission spectrum of the plasma was obtained to determine the species present in the ionization processes of the corona discharge. The energy yield value was calculated in terms of G 50 , these results provide information for the subsequent application of this process to degradation of organic compounds.

IEEE Transactions on Plasma Science, 2017

The variations in the physical and chemical parameters involved in the degradation of dye Acid Bl... more The variations in the physical and chemical parameters involved in the degradation of dye Acid Black 52 (AB52) using plasma were analyzed. The plasma, or electrical discharge, was generated in the gas-liquid interface at atmospheric pressure using a dc power supply. The system configuration comprised two tungsten electrodes: the cathode is immersed in the solution while the anode is fixed above the surface with a gap of 5 mm, where the plasma is generated. The absorbance, total organic carbon, chemical oxygen demand, pH variation, electrical conductivity, optical emission spectrum, and the change in volume and temperature were measured for each sample as a function of treatment time. Index Terms-Absorbance, atmospheric pressure plasma, chemical oxygen demand (COD), optical emission spectroscopy (OES), textile dye, total organic carbon (TOC). I. INTRODUCTION W ATER pollution is an important environmental problem globally; therefore, techniques for the treatment of contaminated water must be developed. Recent studies based on techniques such as ultraviolet (UV) photolysis, Fenton process, direct ozonation, ultrasonification, and nonthermal plasma have shown the possibility of degrading pollutants in wastewater [1]-[4]. However, these techniques produce ozone and consume large amounts of energy because of their low efficiency [5]. Dyes are widely used in the textile industry, and are classified based on their chemical structure. The Color index assigns to dyes known has 25 structural classes according to the type of chemical, the most important structure are: azo dyes, anthraquinone dyes, and phthalocyanines; all dyes, except natural ones, are environment pollutants.

Revista Mexicana de Ingeniería Química, 2019

Modelado de la biodegradación en biorreactores de lodos de hidrocarburos totales del petróleo int... more Modelado de la biodegradación en biorreactores de lodos de hidrocarburos totales del petróleo intemperizados en suelos y sedimentos (Biodegradation modeling of sludge bioreactors of total petroleum hydrocarbons weathering in soil and sediments)

DESALINATION AND WATER TREATMENT, 2019

Hydrocarbon Pollution and its Effect on the Environment, 2018

Polycyclic aromatic hydrocarbons (PAHs) are formed in natural processes during combustion of biom... more Polycyclic aromatic hydrocarbons (PAHs) are formed in natural processes during combustion of biomass (e.g., forest fires) and by anthropogenic activities at high temperatures. In according with the suggestion the major sources of PAHs in the environment. The main sources of PAHs come basically from heat and power generation (e.g., coal, gas, wood, and oil), industrial processes (e.g., coke production), refuse burning and vehicle emissions. Human exposure to airborne PAHs can result from these processes, as well as from emissions from other sources, such as cooking, smoking, and materials containing PAHs (e.g., petroleum products and fuels). The potential serious health effects resulting from acute and chronic human exposure to PAHs are of concern. For this reason, the identification and quantification of PAHs in airborne particles have been a real challenge, given the multiple impacts that these substances represent for human health. In the last decade, multiple technological developments have been implemented, ranging from sampling systems, extraction and analysis of these compounds with the aim of obtaining more accurate and reliable results. This chapter was prepared to describe and to assess the state of the art about the evolution and application of sampling, extraction and analysis methodologies for the determination of PAHs in airborne particles.

IEEE Transactions on Plasma Science, 2015

In this paper, the addition of Ar to H 2 is experimentally investigated. This paper primarily aim... more In this paper, the addition of Ar to H 2 is experimentally investigated. This paper primarily aims to observe the effects that this addition has on the intensity of hydrogen emission lines in a glow discharge mixture. The total pressure was 3 torr, at a power level of 3.9 W. Optical emission spectroscopy was used for plasma characterization, and the principal species observed were H γ (434 nm), H β (486.1 nm), H α (656.3 nm), and H 2 (603.1 nm), and Ar I (750.5 nm), Ar I (763.5 nm), and Ar I (811.6 nm). The electron temperature and ion density were determined by a double Langmuir probe. The electron temperature was found to be in the range of 2.5-6.5 eV, and the ion concentration was on the order of 10 9 cm −3. Index Terms-Balmer lines, glow discharge, low pressure plasma, low temperature plasma, optical emission spectroscopy (OES) of cold plasma.

Solar Energy Materials and Solar Cells, 2011

Fe III supported on ceria as an effective catalyst for oxidation was prepared and used for the de... more Fe III supported on ceria as an effective catalyst for oxidation was prepared and used for the degradation of basic orange 2 azo textile dye (BO2). BO2 was chosen as a model pollutant and the catalytic oxidation was carried out in a batch reactor using hydrogen peroxide as the oxidant at pH 3. The influent factors on BO2 oxidation, such as catalyst dosage, H 2 O 2 concentration, and BO2 concentration were studied by considering the BO2 conversion and chemical oxygen demand (COD) removal. The Fe III-ceria catalyst showed a high catalytic activity for the oxidation of BO2 in aqueous solution. It was observed that the solution became colorless after 5 h of oxidation and over 90% COD removal was achieved with all the Fe III-ceria catalysts used under dark conditions in the catalytic oxidation system. The catalytic removal of BO2 during BO2 oxidation was improved under solar radiation, which notably increased the BO2 degradation rate. Consecutive BO2 oxidation cycles carried out with the same Fe III-ceria catalyst and untreated fresh dyestuff solution showed that the catalyst had good stability and good degradation performance, thus evidencing the possibility of being used in continuous processes. This study showed that the Fe III-ceria catalytic oxidation process is an efficient method for the treatment of BO2 aqueous solutions.

American Journal of Environmental Sciences, 2008

The degradation of water soluble corn oil wastes was carried out by Fenton reaction and also unde... more The degradation of water soluble corn oil wastes was carried out by Fenton reaction and also under mildly basic media in the presence of oxidants, such as hydrogen peroxide and persulfate, assisted with solar light. The degradation efficiency was obtained by analysis of chemical oxygen demand, carbon dioxide and gas chromatography. Over 90% of both chemical oxygen demand abatement and carbon dioxide recovery was accomplished by Fenton reaction. The presence of oxidants during the photodegradation resulted in high chemical oxygen demand abatement of the oil waste with the disappearance of the majority of the initial fatty acids present in the oil waste before treatment.

La industria textil genera grandes cantidades de agua residual contaminadas principalmente por co... more La industria textil genera grandes cantidades de agua residual contaminadas principalmente por colorantes los cuales pueden ser toxicos y persistentes. Este presenta un problema importante debido a la gran cantidad de agua residual proveniente de la industria textil, poniendo en peligro la calidad del agua a donde esta es descargada, la vida acuatica y la salud de los seres humanos. Se ha demostrado que la aplicacion de los procesos de oxidacion avanzada (PAOs) tiene un papel importante en la degradacion de estos contaminantes. En el presente proyecto se trabajo con los procesos Fenton y foto Fenton para la degradacion del colorante negro acido 52, colorante soluble en agua y usado para tenir fibras poliamida como el nylon. Ambos procesos presentan buenos resultados a nivel experimental, se ha demostrado que remueven mas del 90 % de la materia organica presente en el agua bajo tiempos de accion desde 30 a 120 minutos, lo que los convierte en procesos eficientes.

En la industria textil se producen grandes cantidades de agua residual con colorantes que represe... more En la industria textil se producen grandes cantidades de agua residual con colorantes que representan un gran problema ambiental, es por ello que se deben utilizar Proceso de Oxidacion Avanzada para su degradacion. Los reactivos utilizados en la degradacion del colorante Negro acido 52 fueron de FeSO4 a 50 mM y H2SO4 a 0.1 M, CuSO4 50mM y Al2SO4 50mM y agua destilada. El colorante textil fue proporcionado por una industria textil de la Region Oriente de Estado de Morelos. Se empleo un Plasma No Termico producido por corriente directa. La implementacion del plasma no termico se probo con distintas concentraciones del reactivo FeSO4 y variando el tiempo de aplicacion del plasma para determinar la concentracion y el tiempo optimo de degradacion; a su vez se probaron otros reactivos como Al2(SO4)3 y CuSO4 para comprobar su efecto en la oxidacion y degradacion del colorante Negro acido 52 (NA52). Las pruebas se realizaron en un reactor BACH de 250 ml a un pH de 2.4-2.6. La Remocion optim...