Revista Mexicana de Ingeniería Química 2022-07-20T22:51:13+00:00 Francisco J Valdes Parada Open Journal Systems <div class="_4wyf">The Mexican Journal of Chemical Engineering &nbsp;(ISSN 1665-2738,&nbsp; issn-e: 2395-8472) publishes original research papers with the aim of promoting a rapid share of relevant research in various disciplines of Chemical Engineering and its interfaces with other enigineering disciplines. A volume is published each year and it consists of three issues, which are published every four months.&nbsp;</div> Hydrodynamics evaluation of an internal-loop airlift reactor with Newtonian and shear-thinning fluids: Experimentation vs CFD simulation 2022-04-18T23:12:20+00:00 R. Guadarrama-Pérez V.E. Márquez-Baños J.J. Valencia-López V. Sánchez-Vázquez G. Martínez-De Jesús J. Ramirez Munoz M. Gutiérrez-Rojas <p>The hydrodynamics of an internal-loop airlift reactor was numerically and experimentally characterized. The gas holdup, liquid velocity, shear rate, flow pattern and volumetric oxygen transfer coefficient (<em>k<sub>L</sub>a</em>) were evaluated as a function of the air velocity and medium rheology. Tap water and CMC solutions were used as Newtonian and non-Newtonian fluids, respectively. The standard <em></em><em></em> model was employed for modeling turbulence, and unsteady three-dimensional simulations with the Euler–Euler model were performed. Gas holdup, liquid velocity and <em>k<sub>L</sub>a</em> measurements were performed for validating simulations. An increase in bubble coalescence and a decrease in <em>k<sub>L</sub>a</em> was observed with CMC solutions. The presence of recirculation loops inside the riser for CMC solutions is reported, which was not observed with tap water. The higher the CMC concentration, the larger the recirculation region seems to be. Results show that recirculation loops play a substantial role in the reactor’s hydrodynamic performance, and it turns out that the gas holdup in the riser increases with increasing the CMC concentration.</p> 2022-04-18T23:12:20+00:00 ##submission.copyrightStatement## Importance of the C/N-ratio on biomass production and antimicrobial activity from marine bacteria Pseudoalteromonas sp 2022-04-20T14:25:53+00:00 R. López-Alcántara J.L. Borges-Cu J.E. Ramírez-Benítez A. Garza-Ortiz L.A. Núñez-Oreza O.H. Hernández-Vázquez <p>The main objective of this study was to investigate from the physiological point of view, the influence that nitrogen and carbon sources have on the biomass production and activity of the antimicrobial protein of <em>Pseudoalteromonas</em> sp. The impact of the change in the medium initial C/N-ratio on biomass production and antimicrobial activity against <em>S. aureus</em> MRSA was evaluated using two different carbon sources (glucose or citrate) and a fixed concentration of NH<sub>4</sub>Cl as a nitrogen source. The change in total nitrogen concentration in the medium was evaluated using organic or inorganic nitrogen sources (NH<sub>4</sub>Cl or yeast extract-peptone) while a fixed glucose concentrations was present.</p> <p>The results showed that the increase in C/N-ratio stimulated biomass production but inhibited antimicrobial activity regardless of the nature of the carbon source. Similarly, the biomass profile and antibiotic activity were dependent in the variation of low nitrogen total concentrations in the medium and especially at concentrations bigger than 3 g L<sup>-1</sup> negatively affected the antimicrobial activity. This indicated that the main factor affected the secondary metabolism of <em>Pseudoalteromonas</em> sp. was the nitrogen concentration over C/N-ratio.</p> 2022-04-20T14:25:53+00:00 ##submission.copyrightStatement## Mathematical model to estimate volumetric oxygen transfer coefficient in bioreactors using conformable calculus 2022-04-22T20:21:43+00:00 R. Melgarejo-Torres D. Rosales-Mercado M.A. Polo-Labarrios G. Fernández-Anaya M. Morales-Ibarría S.B. Pérez-Vega M.B. Arce-Vázquez D.M. Palmerín-Carreño <p>This work proposes a novel mathematical model based on time conformable derivative convective mass transfer equation to calculate the volumetric oxygen transfer coefficient (<em>k<sub>L</sub>a</em>) in a bioreactor. To validate the novel model, a full mixed-level experimental design was proposed with two factors: agitation speed and dispersed phase. The model employs the conformable derivate order operator (<em>α</em>) and the electrode constant (<em>k<sub>p</sub></em>), which changes with electrode use and the operating conditions of the bioreactor. The results show that when the viscosity increases and the agitation decreases, the value <em>α</em> increases, and vice versa. Therefore, <em>α</em> is a parameter that has a physical meaning in the process. The correlation coefficient of the proposed model with the experimental data (R<sup>2</sup> &gt; 0.985) is higher than the one obtained with conventional models. The Akaike information criterion determined that the proposed conformal model describes the experimental data by 59%, while the conventional models describe the experimental data by 25% and 15%. There are no reports of similar mathematical models that determine mass transfer coefficients in bioprocesses.</p> 2022-04-22T20:04:04+00:00 ##submission.copyrightStatement## Bioleaching of As from mine tailings using an autochthonous Bacillus cereus strain 2022-04-26T14:44:33+00:00 A.M. Cabrales-González M.A. Martínez-Prado D.M. Núñez-Ramírez E.R. Meléndez-Sánchez L. Medina-Torres R. Parra-Saldivar <p>Contamination of heavy metals has been a serious environmental problem due to increasing anthropogenic activities such as mining, smelting, livestock, landfills, waste dumps, and agriculture. Bioleaching experiments were conducted using native <em>Bacillus cereus</em> MAMPE19 BCG, isolated and characterized from previous research, to test removal of arsenic (As) from actual mining waste. Mineralogical characterization by XRD was performed to identify mineral associations with As. The experimental design included a bioleaching system with agitated flasks (triplicate) and the effects of pH (5, 7, and 9) and pulp density (10, 15, and 20%) were evaluated. Finally, based on the results of the ANOVA, the system that achieved the highest percentage of As dissolution was selected and scaled to a stirred tank bioreactor. The composition of the mineral was mainly calcite (CaCO<sub>3</sub>), gismondine (CaAl<sub>2</sub>Si<sub>2</sub>O<sub>8</sub>·4(H<sub>2</sub>O)), akermanite (Ca<sub>2</sub>MgSi<sub>2</sub>O<sub>7</sub>), and silicon oxide (SiO<sub>2</sub>). Native <em>Bacillus</em> <em>cereus</em> dissolved 40.6 ± 4.9 and 37.4 ± 2.7 % of As in 10 d, in agitated flasks at a pH of 5 and a pulp density of 10 and 15%, respectively; and a 27.5 ± 2.9% dissolution of As was achieved in the stirred tank bioreactor at pH 5 and pulp density of 15%, supported by significant statistical differences.</p> 2022-04-26T14:38:01+00:00 ##submission.copyrightStatement## Formulation and characterization of Ciprofloxacin encapsulated liposomes: In vitro antimicrobial activity against multi drug resistant Salmonella typhi 2022-06-26T19:24:04+00:00 M. Aslam M. Iqtedar H. Saeed R. Abdullah A. Kaleem <p>Since decades antibiotics are used against bacterial infections, however for past few years world is fronting serious challenge due to emergence of bacterial antibiotic resistance for which new alternatives of cure are being sought. Liposomes are universally used nano-carriers designed to carry drug safely to action site. Emergence of antibiotic resistance in <em>Salmonella typhi</em> has left us with very few choices of cure. In current study liposomes were designed to carry ciprofloxacin and <em>In vitro</em> efficacy analyzed against multi drug resistant<em> Salmonella typhi</em>. Ciprofloxacin loaded liposomes prepared with Bx-DSPE-PEG(2000) (0.1%), total 100mg lipids, Phosphatidylcholine (PC) and Cholesterol (CH) at ratio of 5:3 had 93.95% encapsulation efficiency. Efficacy was observed through MIC and MBC by time kill assay. The encapsulation efficiency of cipro-loaded liposomes increased from 30% to 93.95% with increase cholesterol content. They showed slow to fast reléase, stability reduced from 93.95% to 71.9% over period of 9 months. Polydispersity index &nbsp;was 0.7, particle size 95.27nm with -20.58mV zeta potential. As compared to drug alone MBC and MIC achieved for ciprofloxacin encapsulated liposomes was at lower drug concentrations i.e. 15 µg/ml, and 10 µg/ml. Conclusively, ciprofloxacin encapsulated liposomes prooved an effective <em>in vitro</em> drug delivery method against MDR <em>Salmonella typhi</em>.</p> 2022-06-26T19:19:15+00:00 ##submission.copyrightStatement## Benign and straightforward synthesis of lignan-type dimers using crude peroxidase from red radish (Raphanus sativus var sativus) 2022-06-29T00:14:43+00:00 A. Navarro M. Gimeno S. Alatorre-Santamaría A. Navarro-Ocaña <p>Alkyl esters of hydroxycinnamic acids and vanillin derivatives were used as model compounds in the oxidative coupling reactions catalyzed by a crude enzymatic extract of <em>Raphanus sativus</em> var <em>sativus</em> (red radish). Six products were isolated and characterized: three alkyl esters of hydroxycinnamic acids dimers and three vanilloids dimers. Herein, we report the enzymatic extract of<em> Raphanus sativus</em> var. <em>sativus</em> showed peroxidase activity catalyzing the oxidative coupling of phenols. Vanilloid dimers were coupled in an ortho-ortho way as expected, while alkyl ester dimers were formed through 5-8 and 8-8 bonds via a radical mechanism prior to cyclization</p> 2022-06-29T00:14:42+00:00 ##submission.copyrightStatement## A systematic derivation of the Monod equation for multi-substrate conditions 2022-07-02T15:32:02+00:00 M. Meraz V. Sanchez-Vazquez F. Martinez-Martinez <p>A simple kinetics scheme was considered for the systematic derivation of the Monod equation for multi-substrate conditions. The model derivation is based on a series expansion of the system solution in terms of a characteristic time constant. The multi-substrate Monod equation is structurally similar to the single-substrate Monod equation, containing terms that reflect the competitive interactions between the different substrates. Biodegradation of phenol-toluene was used to illustrate the ability of the Monod model for describing experimental data.</p> 2022-07-02T15:32:02+00:00 ##submission.copyrightStatement## Large amplitude oscillatory shear (LAOS) rheology of candelilla wax/canola oil oleogels 2022-07-02T15:47:16+00:00 Y. Carrera M. Gonzalez M. E. Rodriguez-Huezo M. Meraz <p>Candelilla wax (CW) was added in 5, 6 and 7% w/w to canola oil (CO), heating the mixtures to 90 <sup>o</sup>C, and cooling down to room temperature, in order to obtain CW/CO oleogels. The nonlinear viscoelastic characteristics of the oleogels was conducted by means of large amplitude oscillatory shear (LAOS) methods. To this end, Fourier analysis of the stress-time response was carried out to extract information on high-harmonic oscillatory moduli. The results showed that nonlinearities were expressed for moderate strain deformations, of the order of 1-15%. In particular, nonlinearities quantified in terms of the harmonic contributions were stronger for the elastic response (about 85-125%) than for the viscous response (less than 40%). In contrast, the mechanical response was essentially harmonic for small amplitude values, indicating the absence of nonlinearities and hence the dominance of linear viscoelastic response. Interestingly, the viscoelastic response was also linear for large strain deformation (&gt;100%). The results reported in the present study demonstrated the viability of LAOS method for obtaining invaluable insights regarding the nonlinear mechanical response of edible oleogels made with natural waxes.</p> 2022-07-02T15:47:16+00:00 ##submission.copyrightStatement## Methyl jasmonate enhances the anti-inflammatory effects of the adventitious roots in Abeliophyllum distichum by increasing the production of polyphenolic compounds 2022-07-11T02:25:38+00:00 T.K. Hyun S.G. Bang M.-A. Ahn S.H. Eom W.T. Joeng <p><em>Abeliophyllum distichum</em> has been demonstrated to possess anticancer, anti-inflammatory, anti-osteoporotic, and anti-obesity effects. However, there is a limitation to using this shrub as a beneficial material, because this shrub had been listed as endangered. Thus, we established an adventitious root culture of <em>A</em>. <em>distichum</em> (AdAR) to overcome this limitation. Solvent-solvent partition fractions from methanol extract of methyl jasmonate (MeJA)-elicited AdAR were used, and the ethyl acetate fraction of MeJA-treated AdAR (EtOAc/MeJA) exhibited strong anti-inflammatory effects in lipopolysaccharide (LPS)-treated RAW264.7 cells. EtOAc/MeJA downregulated the transcription of pro-inflammatory genes and mediators by inhibiting the LPS-activated MEK/ERK signaling pathway. In addition, the results of the phytochemical analysis suggested that MeJA induced the accumulation of polyphenolic compounds, including p-coumaric and ferulic acids, by inducing phenylpropanoid biosynthetic genes in AdAR. These results suggested that AdAR is a viable source for overcoming limitations in the industrial use of <em>A. distichum</em>.</p> 2022-07-11T02:25:38+00:00 ##submission.copyrightStatement## Valorisation of rice husks and bean straws through fuel pellets production: an experimental and modelling approach 2022-04-14T18:48:11+00:00 C. Gutierrez-Antonio N. Hernández-Neri J.F. García-Trejo A.A. Feregrino-Pérez M. Toledano-Ayala <p>Worldwide, agricultural wastes represent an environmental problem due to their high volumes and inadequate disposal. Due to this, valorization of these wastes has been studied, being the production of biofuels a promising option. In particular, rice husks were proposed to produce fuel pellets, buy they do not fulfill the ISO 17225-6 standard due to its elevated ash content; thus, it is required to mix them with other wastes available in the same region. In Mexican states where rice is produced also bean is cultivated, whose residues are not used and have an elevated content of volatile solids. Therefore, the objective of this research is to produce fuel pellets from rice husk and bean straws that meet ISO 17225-6 standard. For this, the densification was carried out using three levels of moisture content and mixing ratios of the biomasses. Based on the experimental data, optimal densification conditions were found through a response surface analysis. Results show that fuel pellets produced from bean straw (90%) and rice husk (10%) with 15.0% of moisture content fulfill ISO 17225-6 standard.&nbsp; At these conditions, fuel pellets have calorific power of 3,645.78 kcal/kg, 6.98 ash, 9.76% final moisture, 610.78 kg/m<sup>3</sup> bulk density, and 99.51% durability.</p> 2022-04-14T18:42:42+00:00 ##submission.copyrightStatement## Use of freeze-drying and convection as drying methods of the xoconostle by-product and the effect on its antioxidant properties 2022-04-19T04:02:09+00:00 A.A. Morales-Tapia F.E. González-Jiménez G. Vivar-Vera J.A. Del Ángel-Zumaya M. Reyes-Reyes L. Alamilla-Beltrán J.E. Barojas-Zavaleta B.L. Cooper-Bribiesca J. Jiménez-Guzmán <p>In this study, the influence of the drying method (lyophilization and convection) on the techno-functional and antioxidant properties of the by-product of xoconostle cv. Cuaresmeño (<em>Opuntia matudae</em>) was evaluated. During convection drying, the effect of the temperature (60, 70 and 80 °C) was evaluated, resulting in drying times of 195, 165 and 120 minutes, respectively. The influence of the temperature on the equilibrium humidity was determined through the drying kinetics, which were affected by increasing the temperature from 60 to 80°C. The drying time for the by-product decreased, and equilibrium humidities of 0.04, 0.03 and 0.02 g water/g dry sample were reached for 60, 70 and 80 °C, respectively. Fick's second law was used along the experiments to determine the effective diffusivity, which ranged from 4.788 E<sup>-10</sup>–8.109 E<sup>-10</sup> m<sup>2</sup>/s for the evaluated temperatures. Convective drying at 60°C proved to be a suitable alternative for the conservation of antioxidant capacity (88.07 ± 0.38% 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition) compared to drying at 70 and 80°C. These were 8% higher compared to the results for freeze drying. However, convective drying at 60°C is more convenient for the xoconostle by-products due to the cost-benefit ratio.</p> 2022-04-19T04:02:09+00:00 ##submission.copyrightStatement## Modification of the nutraceutical characteristics of jalapeño chili peppers in response to hormones 2022-04-21T02:52:58+00:00 H. Medina L. González-Cruz R.G. Olan-Villegas G. Acosta-García N.L. Flores-Martínez A. Bernardino-Nicanor <p>Pot experiments were conducted in a greenhouse of the National Technological of Mexico in Celaya during two summer seasons, in 2019 and 2020, to study the changes in the concentration of nutraceutical compounds in jalapeño chili pepper in response to two phytohormones (gibberellic acid and auxins) and two drying processes (lyophilization and drying by convection oven). Jalapeño chili pepper (<em>Capsicum annuum</em> L.) plants were treated with the phytohormones separately (gibberellic acid, 5 mM solution and auxins (2 mL/L solution)) and mixed together. The obtained results indicated that the freeze-drying process significantly preserved the concentration of nutraceutical compounds and antioxidant activity. The individual application of phytohormones led to significant increases in the concentrations of all nutraceutical compounds and antioxidant activity in the jalapeño chili peppers. However, an antagonist effect of the phytohormone mixture on jalapeño chili pepper production was observed, and for this reason, no jalapeño chili pepper samples were obtained. In conclusion, drying and phytohormonal treatment influence the preservation of nutraceutical compounds and antioxidant activity.</p> 2022-04-21T02:52:58+00:00 ##submission.copyrightStatement## Evaluation of nixtamalization temperature and adding nejayote solids on textural and color properties of dough and tortillas 2022-06-27T16:53:35+00:00 F.J. Guzmán-Rodríguez R.A. Peña-Reyes L. Gómez-Ruiz G.A. Ramírez-Romero A.E. Cruz-Guerrero <p>Nixtamalization is a process given to corn kernels prior to the elaboration of dough and tortillas. It provides adequate texture to maize products but implies a high energy input and releases a considerable volume of waste effluent (nejayote). In this work, the effect of temperature (60 and 90 °C) and the addition of nejayote solids, on textural properties and color of corn dough and tortillas, were studied. It was observed that after nixtamalization at 60 °C the textural properties of corn products did not show a significant difference compared to those at 90 °C. Regarding the addition of nejayote solids, the textural and color properties of the dough and tortillas were not modified, neither at 60 nor at 90 °C, obtaining products with the same attributes as the commercial products. This study will contribute to considerable energy savings in the process and a decrease in solids of the waste effluents can be achieved.</p> 2022-06-27T16:53:35+00:00 ##submission.copyrightStatement## Drying kinetics of Cecina from Yecapixtla using a forced flow indirect solar dryer 2022-07-05T22:25:29+00:00 A. Tlatelpa-Becerro R. Rico-Martínez M. Cárdenas-Manríquez G. Urquiza L.L. Castro-Gómez F.B. Alarcón-Hernández C. Torres E. Montiel <p>This study presents the drying behavior of cecina from Yecapixtla Morelos through an indirect solar dryer to obtain the drying kinetics. The behavior of the drying kinetics was examined, observing significant effects related to the levels of pH, salinity, and density of the cecina. The effective diffusion coefficients D<sub>eff</sub> were 5.673x10<sup>-9</sup>, 2.644x10<sup>-9</sup>, 2.133x10<sup>-8</sup> for three samples corresponding to different days of elaboration. Artisanal dry cecina samples are compared versus the dry cecina of this study. The results showed a higher concentration of salinity and a lower pH of the dry cecina of this study versus the dry artisanal cecina. Solar drying through the indirect dryer present in this work is a viable alternative to give added value to the production of cecina from Yecapixtla in Morelos, Mexico.</p> 2022-07-05T22:09:54+00:00 ##submission.copyrightStatement## Cellulases production from Aspergillus niger-ITV-02 using corn lignocellulosic residues 2022-07-07T00:59:05+00:00 Y.I. Pérez-Salazar C. Peña-Montes S. del Moral M.G. Aguilar-Uscanga <p><em>Cellulases are enzymes used in the hydrolysis of lignocellulosic residues for second-generation (2G) bioethanol production, the low availability in the market, and the high-cost impacts in the 40% of the total cost of 2G bioethanol production. Therefore, it is necessary to look for sustainable alternatives for its production. Cellulases are mainly produced by Aspergillus niger, and their activity can be affected by nitrogen concentration, the use of surfactants, and the carbon source, among others. The objective of this work was to identify enzymes with CMCase and β-glucosidase activity of A. niger ITV-02 from low-cost lignocellulosic residues such as corn and cob stubble in two culture media (M1 and M2). The results showed that using corn stover and medium M2 increased the volumetric activity 1.4 and 1.7 times, respectively compared to corn cob and medium M2. Likewise, enzymes with cellulase activity were identified using carboxymethyl cellulose (CMC) and 4- methyl-lumberyl-β-D-glucopyranoside (MUG). The enzymes identified in MUG correspond to a glucoamylase, two β-glucosidases, and an exo β-xylosidase. In CMC the following were identified: exo-β-1,3-glucanase, endo -β-1,4 xylanase arabinosidase, and endoglucanase</em>.</p> 2022-07-07T00:59:05+00:00 ##submission.copyrightStatement## Cellulose acetate membrane filtration effect on particle size distribution of golden delicious apple juice: Experimental validation of a simulation model 2022-07-08T20:14:34+00:00 N. A. Marrufo-Hernández M. A. Chávez-Rojo M. Hernandez-Guerrero <p>Juice clarification through membranes is becoming an important technology due to its capacity to keep high quality and sensorial characteristics. In the clarification process, the particle size of the feed and the pore size of the membrane give important information about the characteristics and stabilization of the filtered juice. In this work we present an application of a previously reported novel computational simulation used to describe two apple juice filtration systems. Experimental data on the filtration of Golden Delicious (GD) apple juice after two different pre-filtration treatments was obtained and the effect on particle size distribution was studied. The experimental data was compared to the simulation results in which the final mean particle size of filtered juices is determined by the pore size distribution of the membrane and the feed particle size distribution. The error of the simulated values was &lt;10% and therefore the model is valid as a first attempt to provide criteria for membrane selection in the filtration of apple juice and could be scaled to other filtration systems.</p> 2022-07-08T20:14:34+00:00 ##submission.copyrightStatement## Computational study of biomass fast pyrolysis in a fluidized bed reactor 2022-07-02T21:54:53+00:00 C.D. Ahumada J.F. Hinojosa-Palafox V.M. Maytorena C. Pérez-Rábago <p>Biofuels are considered a promising source of renewable energy. Pyrolysis uses heat in an inert atmosphere to break down biomass and produce biofuels like bio-oil (tar) and synthesis gas. This paper presents a computational study of fast biomass pyrolysis in a laboratory fluidized reactor. A laminar flow regime and an Eulerian-Eulerian approach were considered. A comprehensive kinetic model consisting of sixteen irreversible, first-order reactions was coupled with conservation equations of mass, momentum, and energy. The computational model was validated with data reported in the literature. The effect of biomass type and reactor temperature on the thermal decomposition of biomass were analyzed, finding a direct relationship between the content of cellulose and production of tar and similarly between the content of lignin and production of char. Also, the absence of lignin in the biomass dramatically changes the tar and gas compositions. Energy requirements, temperature contours, the composition of the exit gases, and final product yields (tar, char, and gas) are reported.</p> 2022-07-02T21:54:53+00:00 ##submission.copyrightStatement## Acid hydrolysis of hemicellulose from Ipomoea arborescens: kinetics of xylose production 2022-07-05T14:48:05+00:00 A.E. Murillo-Luke J.R. Herrera-Urbina M.A. Martínez-Tellez A.R. Mártin-García <p><em>In this paper the composition change of Ipomoea arborescens was evaluated under acid hydrolysis pretreatment, and the kinetic parameters of this reaction were determined. The goal was to evaluate the effects of particle size in the reaction rate of hemicellulose hydrolysis, and to find the concentration of sulfuric acid in which the reaction mechanism favors hemicellulose hydrolysis of Ipomoea arborescens particles. Once the best conditions were found, Ipomoea arborescens particles were hydrolyzed at different temperatures. A pseudo-homogenous model was adopted to describe hemicellulose hydrolysis. The empirical formula of hemicellulose was determined experimentally to have 21 molecules of xylose, 5 molecules of glucose and 1 molecule of galactose. The mathematical model of hemicellulose hydrolysis is successful to describe the experimental results when the temperature is between 120 and 160°C.</em></p> 2022-07-05T14:48:04+00:00 ##submission.copyrightStatement## Anaerobic digestion of agro-industrial waste: Anaerobic lagoons in Latin America 2022-04-18T22:21:07+00:00 U. Galván-Arzola L.R. Miramontes-Martínez C. Escamilla-Alvarado J.E. Botello-Álvarez M.M. Alcalá-Rodríguez R. Valencia-Vázquez P. Rivas-García <p>The valorization of agro-industrial wastes (AW) by means of waste-to-energy strategies through anaerobic digestion (AD) is a reality in developed countries. In Latin America, there are different problems in the management of AW from intensive livestock farming. This study aims to provide a pseudo-radiography of AD management systems with a focus on anaerobic lagoons in Latin America (LATAM). Using data science, quantitative and qualitative data from 1003 scientific papers were synthesized and analyzed to form a database; which allowed evaluation of the congruence of the scientific research with the real problems of LATAM management. The results showed that anaerobic lagoons in the region are the main AW management systems (mainly bovine and swine manure) and that scientific research in this sector does not address the related problems. 38 types of inhibition phenomena with a total of 5264 mentions were addressed in the database. Nitrogen-related AR inhibition phenomena represented 21% of the incidences in this study, besides being the most significant phenomenon in anaerobic lagoons in LATAM</p> 2022-04-15T02:11:53+00:00 ##submission.copyrightStatement## Pre-evaluation of contaminated soil for oil field reactivation in Moloacan, Veracruz, Mexico 2022-06-30T15:32:21+00:00 M.M. Yzquierdo-Ruíz S.A. Torres-Sánchez I.M. De la Garza-Rodríguez M.E. Ojeda-Morales E. Hernández-Nuñez C.E. Lobato-García M.A. Hernández-Rivera M. Zurita-Macias-Valadez C.M. Morales-Bautista <p>This document presents studies to establish an Environmental Baseline for the oil sector in 13 wells in the Moloacán Field, in Veracruz, México regarding hydrocarbons in soils.&nbsp; Four factors were taken into account: characteristics found in the field, methods for the determination of hydrocarbons (with two methods: the Soxhlet and the Petroflag), effects on fertility properties, and heavy metals content. The results show spills in every well with a high percentage of heavy fractions (mainly polar). However, these are not entirely visible because they are below or between the rhizosphere. Also, higher concentrations of hydrocarbons were found in specific sites such as old incinerators and waste pits. In the waste pits, pollutants had contact with the aquifer. In addition, in the determination of hydrocarbons, the Soxhlet method showed better results than the Petroflag one. Likewise, a relationship between these pollutants and the negative effects on soil properties, such as the increase in densities, electrical conductivity, and sands, as well as the decrease in field capacity and clays were found. Also, pH and salinity increased when the hydrocarbons exceeded the permissible limits (&gt;4400 mg·kg<sup>-1</sup>). Finally, metals such as Cr, V, Ba, Hg, Ni, Pb, and Cd were also found, but only Ni was found at dangerous levels for agricultural use.</p> 2022-06-30T15:32:21+00:00 ##submission.copyrightStatement## Domestic wastewater treatment by electrocoagulation system using photovoltaic solar energy 2022-07-05T22:26:27+00:00 Z.Y. Medrano-Hurtado J.C. Medina-Aguirre H. Marcelo-Medrano A. Castillón-Barraza R. Zamora-Alarcón M.E. Casillas-Lamadrid A.A. Jumilla-Corral P. Mayorga-Ortiz <p>This work deals with the design of a domestic wastewater treatment system for the washing machine, which is mainly based on responsibility to the environment in terms of the correct administration and proper management of the most significant asset that man possesses, water. In Mexican homes, one of the main domestic processes is laundry, where a large amount of water is used to clean clothing. Electrocoagulation is a process that can be used in the treatment of different wastewater due to its versatility and environmental compatibility. In the present investigation, the applicability of electrocoagulation for the treatment of domestic wastewater from the washing machine through the use of photovoltaic solar energy was analyzed. The effects of operational parameters such as current density, treatment time on turbidity, , and conductivity were studied. The objective of this project is to research alternatives to domestic wastewater treatment systems from the washing machine, through the use of photovoltaic panels taking advantage of and reusing the water from the washing machine after each washing process. Reduce the waste of the resources from homes, can contribute positively to the environment, and demonstrate that electrocoagulation is a viable alternative in the challenge of protection, conservation, and recovery of water resources.</p> 2022-07-05T22:26:27+00:00 ##submission.copyrightStatement## Behavior of the AB52 dye degradation in liquid medium by different electrical power non-thermal plasma at atmospheric pressure 2022-07-08T14:24:05+00:00 F.B. Alarcón-Hernández E. Montiel-Palacios M.C. Fuentes-Albarrán A. Tabarez de León J.L. Gadea-Pacheco A. Tlatelpa-Becerro <p>The degradation of Acid Black 52 (AB52) dye in a liquid medium derived from exposure to a non-thermal plasma of air at atmospheric pressure is quantified experimentally. The changes observed in the dilution are measured and compared as a function of the electrical power of plasma generation (15.0 W, 22.5 W, 30.0 W, and 45.0 W), as well as the exposure time (two hundred minutes per electrical power). Dye degradation for each electrical power of plasma was established by comparing the results from UV / VIS spectrophotometry measurements (absorbance, concentration, and percentage of degradation), pH, COD, and TOC. In addition, the toxicity change dilution was determined by performing bioassays using Lactuca sativa lettuce seeds. The changes for each of the variables measured as a function of the electrical power of plasma generation show the following specific mathematical behaviors: Logarithmic (Temperature, TOC, and pH), potential (COD), and linear (Absorbance). Obtained results showed that the increase in the degradation of the dye and the change in toxicity depends directly on the electrical power and the time of exposure to plasma. The maximum degradation obtained from the samples analyzed at the end of the experiments corresponds to 45.0 W, that is, higher electrical power, a higher percentage of degradation.</p> 2022-07-08T14:24:05+00:00 ##submission.copyrightStatement## Wastewater management using cold plasma – Degradation of organic dyes in liquid phase 2022-07-09T04:12:59+00:00 E. Almaraz-Vega D. Guevara-Ruíz M.A. Sánchez-Castillo J.C. Sánchez-Díaz A. Martínez-.Ruvalcaba L.E. Cruz-Barba <p>The use of a plasma reaction system for the treatment of wastewater was evaluated by analyzing the degradation of organic dyes in liquid phase. The reaction system allows the treatment of liquids with plasma generated reactive species in tiny bubbles that increase the contact area between the plasma and the liquid, thus reducing treatment time. The system capability to degrade organic matter was studied using organic dyes in aqueous solution. The discoloration reaction of organic dyes such as methylene blue (MB), methyl orange (MO), and methyl red (MR), as well as the reduction of total organic carbon (TOC), and chemical oxygen demand (COD) were analyzed to determine the efficacy of the system and determine its potential use to degrade organic pollutants in aqueous phase. It was found that after 5 minutes of treatment the solutions practically lost the color, and a significant part of the organic matter.</p> 2022-07-09T04:12:59+00:00 ##submission.copyrightStatement## Development of Heliconia latispatha in constructed wetlands, for the treatment of swine/domestic wastewater in tropical climates, with PET as a substitute for the filter medium 2022-07-19T16:49:49+00:00 E. Fernández-Echeverria L.C. Sandoval Herazo F. Zurita E. Betanzo-Torres M. Sandoval-Herazo <p>The aim of this study was to evaluate the development and effect of <em>Heliconia latispatha</em> in pilot-scale constructed wetlands (CWs) for the treatment of pig wastewater mixed with domestic wastewater, using PET waste as filter medium, in a tropical climate. Six cells filled with rough recycled PET waste were used; 3 operated with vegetation and 3 without vegetation and the study lasted 8 months. The results showed an excellent development of <em>H. latisphata</em> under the flooded conditions, reaching a level of development similar to the level of development in commercial soil crops. The good development of the plant was reflected in the remarkable increase in plant height, stem thickness, number of plants and inflorescences. In addition, the presence of <em>H. latisphata</em> significantly influenced the removal of contaminants (p&lt;0.05) such as COD (chemical oxygen demand), TN (total nitrogen), TP (total phosphorus) and TC (total coliforms), reaching higher removals by 7.8%, 8.5%, 18% and 13.7%, respectively, with respect to the systems without vegetation. The production of <em>H. latispatha</em> flowers and the good removal of pollutants from the influent make the system a viable alternative for the production and commercialization of <em>H. latispatha</em> under tropical climates while at the same time the wastewater is treated.</p> 2022-07-19T16:49:49+00:00 ##submission.copyrightStatement## Effect of drying on the extraction yield of Luma chequen (Molina) A. Gray essential oil 2022-04-19T03:48:00+00:00 M.E. Borja-Málaga A. Jiménez-Ochoa E. Medina-de Miranda F.A. Escobedo-Vargas <p>This work studies the effect of drying at 40 °C of the leaves and stems of the species <em>Luma chequen (Molina) A. Gray </em>on the extraction yield of its essential oil by steam distillation at a pilot scale. From the micromorphological evaluation at the moisture levels fresh state (72±1%), critical moisture (24±1%) and equilibrium moisture (8.2±0.5%), it is found that the tissues fold, the secretory cavities thin out, according to the lacunarity, the microstructure of the plant material exhibits greater uniformity at the critical moisture. For the extraction tests 18 levels of moisture were considered, keeping the packing factor at 54 Kg/m<sup>3</sup>. The maximum yield of 0.52 ± 0.01% <em>(v/w)</em> was reached when the moisture of the material was 22±1%, very close to the critical moisture. A first-order model provided a suitable fit to the extraction kinetic data for samples with different humidity levels. Based on the evaporation rate equation, a description of the microstructure of the material and the drying conditions, a model was developed which shows the evaporation mechanism to be dominant in both the drying process and in the extraction of essential oil.</p> 2022-04-19T03:48:00+00:00 ##submission.copyrightStatement## Effect of particle-size distribution on LiFePO4 cathode electrochemical performance in Li-ion cells 2022-06-30T19:03:53+00:00 P. Cofre A. Quispe M. Grageda <p><em>LiFePO4 has structural and electrochemical advantages that make it an important candidate as a cathodic material. Its low cost, structural stability and low toxicity makes it a good option for energy backup systems. However, it is necessary to address the problem with its low ability to operate at high cycling speeds due its low electrical conductivity and low diffusion coefficient. In this work, the LiFePO4 powders were treated with ultrasound for different periods of time to study the effect of reducing the agglomerated particles in the wet mixture during the manufacturing stage. The samples were characterized by X-ray diffraction, scanning electron microscope, particle-size analysis and electrochemical methods. The results revealed that the ultrasonic treatment reduced the size particle of both active material and conductive additive improving the electrochemical behavior and specific capacity of the samples that were treated for longer periods of time.</em></p> 2022-06-30T19:03:53+00:00 ##submission.copyrightStatement## Tropical atmospheric corrosion of galvanized steel, in a light urban atmosphere in the San José valley of Costa Rica 2022-07-04T19:57:14+00:00 J.E. Rodriguez-Yañez J. Uruchurtu-Chavarin J. Sanabria-Chinchilla <p><em>Costa Rica is an importer of most of the metallic materials it uses. In construction, Galvanized Steel (GS) is one of the most used elements in urban areas, where atmospheric corrosion is the main problem of its environmental deterioration. The area of greatest population and economic activity in Costa Rica is the San José Valley, which has a tropical monsoon climate with low pollution, defined under ISO 9223 as light urban. The present study of the atmospheric corrosion of the GS, proposes a high correlation for simple linear models, with climatic parameters as main components and SO<sub>2</sub> as secondary component. Seasonality and sampling sites are partially significant at the beginning of the oxidation process, but this effect is damped over time. The average corrosion rate after 2 years is in the order of 0,4 </em><em>m</em><em>m y<sup>-1</sup>, which represents a low level (C2 according to ISO 9223). Complex annual corrosion models, such as those indicated by ISO 9223, overestimate the real corrosion value. </em></p> 2022-07-04T19:57:14+00:00 ##submission.copyrightStatement## Electrochemical evaluation of conjugated oligophenylenimine in aqueous medium for bandgap determination 2022-07-20T22:51:13+00:00 M.A. Amado Briseño C. Cortés-López R.A. Vázquez-García V.E. Reyes-Cruz G. Urbano-Reyes A. Trujillo-Estrada A. Espinosa-Roa <p><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">In the present work, three aqueous media were used: sodium acetate (NaC<sub>2</sub>H<sub>3</sub>O<sub>2</sub>), potassium nitrate (KNO<sub>3</sub>) and sodium nitrate (NaNO<sub>3</sub>) at two different scanning speeds, i.e. 50 and 100 mVs<sup>−1</sup>, to evaluate the bandgap of the conjugated oligophenylenimine called DAFCHO by cyclic voltammetry (CV). DAFCHO was synthesised by solid-phase mechanosynthesis from 2,7-diaminofluorene and 2-5-bisocycloxyterephthaldehyde and deposited as a film on a glass substrate. The results showed an electrochemical bandgap range of 2.39 to 2.47 eV at 50 mVs<sup>−1</sup> and from 2.59 to 2.68 eV at 100 mVs<sup>−1</sup>, which are close to the optical bandgap and electrochemical bandgap of 2.56 eV and 2.35 eV obtained on the film, as calculated by UV–vis absorption spectroscopy and determined electrochemically in a BU<sub>4</sub>NPF<sub>6</sub>/ACN electrolyte in the literature. In addition, a greater degradation of the film of the organic compound DAFCHO was observed in the three aqueous media (NaC<sub>2</sub>H<sub>3</sub>O<sub>2</sub>, KNO<sub>3</sub> and NaNO<sub>3</sub>), compared with the anhydrous medium (BU<sub>4</sub>NPF<sub>6</sub>/ACN) from the literature. On the other hand, the electrical evaluation of DAFCHO exhibits the characteristic behaviour of a P-N-type junction diode.</span></span></span></span></p> 2022-07-07T01:03:50+00:00 ##submission.copyrightStatement##