Chromium salts are chemical reagents widely used in the tannery industry because they are efficient for tanning animal skin, however, these salts are not completely fixed, so their remnants go to their effluents, seriously impacting the environment. The objective of this study was to remove chromium (VI) and total chromium from a tannery effluent using electrodialysis, for this purpose, a sample of an effluent from a tannery pilot plant was characterized and then a synthetic solution was prepared based on this, using an industrial grade chrome salt for tannery, then the limiting current was determined and electrodialysis tests were carried out with the 80, 100 and 120% of the limiting current. The results showed that the highest percentage of extraction and the lowest electricity consumption was 80% of the limiting current.

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Las sales de cromo son reactivos químicos muy utilizados en la industria de curtiembre porque son eficientes para curtir la piel animal, sin embargo, estas sales no se fijan totalmente, por lo que, sus remanentes van a parar a los efluentes, impactando gravemente al medioambiente. El objetivo de este estudio fue remover el cromo (VI) y cromo total de un efluente de curtiembre utilizando electrodiálisis, para ello, se caracterizó una muestra de un efluente de una planta piloto de curtiembre y se preparó una solución sintética en base a ésta, utilizando una sal de cromo para curtiembres de grado industrial, luego, se determinó la corriente límite y se realizó pruebas de electrodiálisis con el 80, 100 y 120% de la corriente límite. Los resultados demostraron que el mayor porcentaje de extracción y el menor consumo de energía eléctrica fue al 80% de la corriente límite.

WITH THE GRADUAL INCREASE OF MICROPLASTICS IN WATER BODIES, IT IS ESSENTIAL TO UNDERSTAND THE CURRENT TREATMENT PROCESSES FOR THEIR REMOVAL. THIS STUDY AIMS TO INVESTIGATE THE REMOVAL OF MICROPLASTICS IN SYNTHETIC SOLUTION BY ELECTROCOAGULATION (EC). THE EFFECTS OF ELECTRODE TYPE, CONTACT TIME (MIN), AGITATION SPEED (RPM) AND CURRENT DENSITY (A/M2) WERE EVALUATED USING A FRACTIONAL FACTORIAL DESIGN. THE RESULTS SHOWED THAT THE ALUMINUM ANODE ACHIEVED A HIGHER REMOVAL OF MICROPLASTICS THAN THE IRON ANODE, REACHING 98.04% REMOVAL WITH THE ALUMINUM OPERATIONAL CONFIGURATION WITHIN 15 MIN AT 70 RPM AND A CURRENT DENSITY OF 20 A/M2. A HIGH CORRELATION BETWEEN THE PREDICTED AND OBSERVED REMOVAL WAS EVIDENCED, WITH VALUES OF R2= 0.99 AND ADJUSTED R2= 0.98, INDICATING A GOOD AGREEMENT BETWEEN THE MODEL AND THE EXPERIMENTAL DATA, CONFIRMING THE VALIDITY AND FEASIBILITY OF THE ADOPTED LINEAR MODEL...

The group-contribution method of UNIFAC have been evaluated to predict phase equilibria for the n-butyl acetate-cyclohexane system at low pressures. The results show that this method predicts satisfactorily the studied system. The experimental results were obtained in a boiling point apparatus at low pressures, giving in this way experimental data from which we have scarce information.

El método de contribución de grupos de UNIFAC ha sido evaluado para predecir el equilibrio de fases del sistema acetato de n-butilo-ciclohexano a bajas presiones. Los resultados muestran que el método predice satisfactoriamente los datos de equilibrio líquido-vapor del sistema estudiado. Los resultados experimentales fueron obtenidos en un dispositivo de medición de puntos de ebullición a baja presión, aportando de este modo la data experimental de un sistema del que se dispone poca información.

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In this work the Soave-Redlich-Kwong(SRK), Peng-Robinson (PR) y AGA8-DC92 (AGA) equations of state have been used to predict the density of different natural gas mixtures. AS a result, SRK and PR are strongly recommended for temperatures within the range 240-350 K. As for the pressure, SRK yielded better results within the range 1-8 MPa, whereas PR was more accurate for pressures ranging from 1 to 15 MPa. The errors obtained were smaller than 3% for all the 613 experimental point taken from the literature, which is convenient due to the fact that AGA is not easy to handle. Nevertheless, AGA displayed the best performance in every calculation and proved to be superior to either SRK or PR in the whole range of conditions used in this investigation. Finally, a computational tool has been developed to calculate density (ρ) and compressibility factor (Z). Such a tool incorporates an exp...

En este trabajo se han usado las ecuaciones de estado (EOS) de Soave-Redlich-Kwong (SRK), Peng-Robinson (PR) y AGA8-DC92 (ACA) en la predicción de la densidad para diferentes gases naturales. Se recomienda el uso de las ecuaciones SRK y PR en el intervalo de 240 a 350 K y de 1 a 8 MPa (SRK) y de 1 a 15 MPa (PR), por producir errores menores al 3%, lo que es válido para los 613 puntos experimentales que se tomaron de la literatura; tal situación es ventajosa por ser las ecuaciones de estado más fáciles de manipular que la ecuación AGA. Sin embargo, todos los cálculos realizados demuestran que la ecuación AGA es superior a las ecuaciones SRK y PR en todo el rango de presión y temperatura de los datos experimentales usados. Se ha desarrollado una herramienta computacional para el cálculo de la densidad (ρ) y factor de compresibilidad (z), que incorpora una base de dalos de p expe...

ENVIRONMENTAL POLLUTION FROM MICROPLASTICS (MPS), AN ANTHROPOGENICALLY MEDIATED MENACE TO THE BIOSPHERE, IS A GLOBAL CONCERN. THIS RESEARCH CONDUCTED A BIBLIOMETRIC ANALYSIS OF MPS IN SOIL AND TERRESTRIAL ECOSYSTEMS USING R SOFTWARE AND BIBLIOSHINY TO ANALYZE DESCRIPTIVE STATISTICS, AUTHOR CONTRIBUTIONS, DOCUMENTS, AND CONCEPTUAL STRUC-TURES. THE SCOPUS DATABASE WAS SELECTED, AND VARIOUS KEYWORDS OPTIMIZED THE SEARCH. AN ANALYSIS OF RESEARCH TRENDS DIVIDED THE TIMELINE INTO THREE PERIODS: PERIOD I (2012–2018), PERIOD II (2019–2021), AND PERIOD III (2022). RESULTS SHOWED WANG J. AS THE AUTHOR WITH THE HIGHEST H-INDEX, WHILE SCIENCE OF THE TOTAL ENVIRONMENT HAD AN H-INDEX OF 43. IN PERIOD I, RESEARCH FOCUSED ON MPS AND PLASTIC POLLUTION, RAISING QUESTIONS ABOUT THEIR IMPACTS ON TERRESTRIAL ECOSYSTEMS. RESEARCH FOUND THAT MPS NEGATIVELY AFFECTED SOIL ORGANISMS BY DECREASING GROWTH RATES...

THE AIM OF THIS BIBLIOMETRIC ANALYSIS WAS TO EVALUATE THE EVOLUTION OF SCIENTIFIC RESEARCH IN HYDROGEN, FOCUSING ON GREEN HYDROGEN PRODUCTION, STORAGE, AND UTILIZATION. ARTICLES FROM PROMINENT DATABASES WERE ANALYZED, REVEALING A STRONG EMPHASIS ON SUSTAINABLE HYDROGEN TECHNOLOGIES THROUGH KEYWORDS LIKE “HYDROGEN PRODUCTION”, “GREEN HYDROGEN”, AND “SOLAR POWER GENERATION”. MATURE RESEARCH AREAS INCLUDE PRODUCTION METHODS AND ELECTROLYSIS, WHILE EMERGING TOPICS SUCH AS ENERGY EFFICIENCY AND POLICY ARE GAINING TRACTION. THE MOST-CITED PAPERS, FROM ENERGY CONVERSION AND MANAGEMENT TO THE INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, COVER TECHNO-ECONOMIC ASSESSMENTS AND CASE STUDIES ON DEPLOYING HYDROGEN TECHNOLOGIES. KEY FINDINGS HIGHLIGHT THE VARIABILITY OF THE LEVELIZED COST OF HYDROGEN (LCOH) ACROSS TECHNOLOGIES AND REGIONS. DEEP LEARNING APPLICATIONS, INCLUDING FAST FOURIER TRA...

THE OBJECTIVE OF THIS RESEARCH WAS TO EVALUATE THE SUSTAINABILITY OF A CO-TREATMENT SYSTEM THAT COMBINES MUNICIPAL WASTEWATER (MW) AND ACID MINE DRAINAGE (AMD) THROUGH THE TECHNIQUE OF INTERMITTENT ELECTROCOAGULATION, APPLIED AS AN ADVANCED SOLUTION TO IMPROVE CONTAMINANT REMOVAL EFFICIENCY AND OPTIMIZE ENERGY BALANCE. FOUR SCENARIOS WERE ANALYZED: TREATMENT I (WITH A 1/7 RATIO OF URBAN WASTEWATER TO AMD), TREATMENT II (WHICH INCLUDES AN ARTIFICIAL WETLAND), TREATMENT IIIA (WHICH INTRODUCES ELECTROCOAGULATION TO ENHANCE SULFATE REMOVAL AND PH REGULATION), AND TREATMENT IIIB (WHICH EMPLOYS A 1/15 RATIO OF AMD TO EUTROPHIC WATER). THE METHODOLOGY FOCUSED ON CALCULATING KEY SUSTAINABILITY INDICATORS SUCH AS THE NET YIELD RATIO (EYR), EMERGY INVERSION RATIO (EIR), ENVIRONMENTAL LOADING RATIO (ELR), AND SUSTAINABILITY INDEX (SI), IN ORDER TO ASSESS THE IMPACT OF EACH TECHNOLOGY ON THE ENERGY ...

The textile industry is known for its excessive water consumption and environmental impact. One of the major challenges it faces is managing pollution generated by dyes, particularly bifunctional dyes, such as sumireact supra yellow s-hbu, with a red appearance and sumifix supra lemon-yellow e-xf, with a yellow appearance. This study aimed to investigate the decolorization kinetics of synthetic solutions of said bifunctional dyes, which comprise triazine and vinylsulfon. We conducted various tests, including modifications of pH, the addition of TiO2 P-50 nanoparticles, exposure to solar radiation, limited contact with oxygen, and eolic agitation. The initial solutions had a concentration of 1000 ppm of textile dye. The study showed that the reaction order for the “red” solutions in the R6 and R9 reactors and all the yellow solutions was ½. The concentration of nanoparticles and pH h...