Person:
Cruzat Contreras, Christian Américo

Birth Date

1975-04-14

ORCID

0000-0002-4373-1407

Scopus Author ID

25927026000

Afiliación

Universidad de Cuenca, Cuenca, Ecuador
Universidad de Cuenca, Centro de Estudios Ambientales, Cuenca, Ecuador
Universidad de Cuenca, Departamento de Química Aplicada y Sistemas de Producción, Cuenca, Ecuador
Universidad de Cuenca, Facultad de Ciencias Químicas, Cuenca, Ecuador
Universidad de Concepción, Concepción, Chile
Universidad de Cuenca, Departamento de Recursos Hídricos y Ciencias Ambientales, Cuenca, Ecuador

País

Ecuador

Organizational Units

Organizational Unit

Facultad de Ciencias Químicas

Fundada en 1955 como la Escuela de Química Industrial, la facultad ha sido un pilar fundamental en la formación de profesionales altamente capacitados, comprometidos con el desarrollo de la ciencia, la educación y el bienestar social. La Facultad de Ciencias Químicas pone a consideración su trabajo académico, investigativo y de vinculación con la sociedad, desarrollado a través de la práctica de una docencia de calidad, investigación e innovación en su área de estudio. Desde su oficio de conocimiento se permite contribuir a la sociedad con cuatro carreras: Bioquímica y Farmacia, Ingeniería Química, Ingeniería Ambiental e Ingeniería Industrial. Su carta de presentación en la Academia, la coloca como una dependencia dinámica, donde confluye la solidez de una trayectoria de más de sesenta años. Aquí se trabaja en una continua formación de pregrado y posgrado de la más alta calidad, mediante la mejora continua con la innovación y a la vanguardia de las ciencias químicas.

Job Title

Profesor (T)

Last Name

Cruzat Contreras

First Name

Christian Américo

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Search Results

Now showing 1 - 10 of 17

A new approach for scaling up fixed-bed adsorption columns for aqueous systems: a case of antibiotic removal on natural adsorbent
(2022) Juela Quintuña, Diego Marcelo; Vera Cabezas, Luisa Mayra; Cruzat Contreras, Christian Américo; Astudillo Alemán, Ana Lucía; Vanegas Peña, María Eulalia
The scaling up of adsorption columns is a crucial step toward the removal of emerging pollutants from domestic and industrial wastewaters. In this study, a fixed-bed column to remove sulfamethoxazole packed with sugarcane bagasse was scaled up from laboratory (DL = 2.2 cm) to pilot unit (DP = 4.4 cm) using a scaling factor (K = 2). In addition to the basic similarity rules for scaling, three new criteria were proposed for the mass adsorbent, flow rate, and bed volume. Then, three lab-scale tests at flow rate of 5 mL/min and bed heights of 15, 25, and 35 cm were transferred to the pilot-scale column at flow rate of 20 mL/min and bed heights of 30, 50, and 70 cm, respectively. The breakthrough curves and the fixed-bed parameters (residence time tR, saturation time ts, adsorption capacity qe, volume of solution treated Vef, and removal percentage %R) obtained in both scales were compared to define their effect with the increase of scale. Finally, a mechanistic model was proposed to predict the breakthrough curves in both columns. The results exhibited that the breakthrough curves in the pilot-scale prolonged in time with higher breakthrough and saturation times than the laboratory breakthrough data. Additionally, tR, ts, and Vef changed in function of the K value used: ts and tR doubled their value in the pilot column or ; Vef was eight times higher in the pilot column than the lab-column or ; qe and %R remained constant in both scales; these results were corroborated with the predicted breakthrough curves. Besides, the mechanistic model predicted with great precision the breakthrough data in both scales (R2>0.9), which means that the model can be used confidently for scaling up purposes. This study demonstrated new criteria which can be easily applied to scale up adsorption columns whit results that showed a correlation between both scales.
Effect of cation substitution on magnetic properties in Mn1−xA’xCr2S4 (A’ = Cd, Zn) thiospinel series
(2007) Moure, Carlos; Cruzat Contreras, Christian Américo; Raison, Ch; Manríquez Castro, Víctor; Galdámez Silva, Antonio César; Barahona Huenchumil, Patricia Mabel; Le Coz, Xavier; Peña, Octavio
Colossal magnetoresistance (CMR) materials such as REMnO3 perovskites and AB2S4 thiospinels have been well studied in the past. The authors present thiospinel compounds with A = Mn, since they may be viewed as a link to REMnO3 CMR perovskites. Ferrimagnetic MnCr2S4 is known to present a T c of 65 K and a magnetic transition towards a non-collinear Yafet-Kittel state. The (Mn1−xA’x)Cr2S4 series (A = Cd, Zn) was synthesised at 850°C. This series crystallises in the space group Fd3m with a close to 10 Å. When A’ = Cd (T c ranging from 68 K, x = 0·2, to 79 K, x = 0·6), the ferromagnetic features are enhanced, indicating that antiferromagnetism between Mn spins is progressively lost. For A’ = Zn, two magnetic transitions take place, one at 15 K, which is reminiscent of the antiferromagnetic state of ZnCr2S4 and another one at T c = 115 K. Impurities which could be responsible of these two magnetic states are excluded.
Potential biopolymer adsorbent functionalized with Fe3O4 nanoparticles for the removal of Cr(VI) from aqueous solution
(2022) Vanegas Peña, María Eulalia; Castro Tamay, Pablo Reinaldo; Novoa, Néstor; Arrué, Ramón; Juela Quintuña, Diego Marcelo; Cruzat Contreras, Christian Américo
In the present study, an adsorbent with a synergistic effect was developed from chitosan (CS) and Fe3O4 nanoparticles (Fe3O4 Nps) to remove Cr(VI) from aqueous solutions. The Fe3O4 Nps were synthesized by co-precipitation and were characterized by TEM. The CS/NPs composites were prepared by electrospinning technique and analyzed by SEM, FT-IR, DSC, and TGA. In the batch system, the influence of Fe3O4 Nps content, pH, contact time, Cr(VI) initial concentration, adsorbent dosage, and the temperature was investigated; the Cr(VI) concentration was determined using a colorimetric method by UV–Vis spectroscopy. The Fe3O4 Nps presented a quasi-spherical shape and an average size of 18 nm, with a low particle distribution. The SEM analysis reveals the presence of highly porous, interconnected micrometric structures. The optimal adsorption conditions were 1% load of Fe3O4 Nps by weight of CS, pH 3, 25 °C, and equilibrium was reached at just 9 min. Besides, the adsorption is favored by increasing Cr(VI) initial concentration and adsorbent dosage. The studies of reaction kinetics and adsorption equilibrium showed that the experimental data were better fitted to the Pseudo-second-order and Langmuir isotherm models, establishing monolayer formation and chemisorption. The maximum adsorption capacity of CS/ Fe3O4 Nps was 440.75 mg/g, which indicates a high affinity of the adsorbent for Cr(VI). Finally, a kinetic diffusion study established that intraparticle diffusion, and in particular surface diffusion, are important resistances in the transport of Cr(VI) from the liquid phase to the active site.
Modeling and computational fluid dynamic simulation of acetaminophen adsorption using sugarcane bagasse
(2021) Vera Cabezas, Luisa Mayra; Juela Quintuña, Diego Marcelo; Cruzat Contreras, Christian Américo; Vanegas Peña, María Eulalia
Evaluación toxicológica de soluciones acuosas de ibuprofeno mediante bioensayos con Artemia salina, Allium schoenoprasum L y Lactuca sativa
(2018) Saetama Guallpa, Maria Veronica; Vera Cabezas, Luisa Mayra; Vanegas Peña, María Eulalia; Cruzat Contreras, Christian Américo; Brazales Quizhpe, Diana Esperanza
Drugs are considered within the so-called emerging pollutants, so it is important to investigate the toxic effects they can produce in the environment. The aim of this study was to determine the toxic effect of aqueous solutions of ibuprofen on an aquatic organism Artemia salina and the seeds of Allium schoenoprasum L and Lactuca sativa. The toxicity tests were carried out by exposing the test organisms to concentrations of aqueous ibuprofen solutions of 20, 10, 5, 2, 1 and 0.5 mgL-1. The percentage of mortality for Artemia salina and the elongation of the radicle and hypocotyl for the seeds were determined. The highest mortality percentage occurred at the concentration of 20 mgL-1, the calculated LC50 was 17.386 mgL-1. A low toxic effect was present in the germination of the seeds of Allium schoenoprasum L. There was inhibition in the elongation of the radicle and hypocotyl in seeds of Allium schoenoprasum L and a stimulation effect in the elongation of the radicle and hypocotyl of the seeds of Lactuca sativa. The highest inhibition effect was presented at 1 and 20mgL-1 and the highest stimulation at 20 mgL-1.
Study of aggregation of gold nanoparticles in chitosan
(2018) Cardenas Triviño, Galo; Cruzat Contreras, Christian Américo
In this work it is reported the synthesis of gold nanoparticles supported in situ in chitosan by solvated metal atom dispersion technique in order to study the inclusion of Au nanoparticles in the biopolymer matrix. To study their aggregation along time and compare with the synthesis of Au/2-propanol colloid by chemical liquid deposition technique. Studies of Au nanoparticles aggregation along time, supported nanoparticles and colloidal nanoparticles morphology were also carried out. The characterization of Au nanoparticles was performed by transmission electron microscopy, field-emission and scanning electron microscopy, infrared spectroscopy, X-ray diffraction, light scattering and ultraviolet–visible spectroscopy. Metal colloid showed fractal agglomeration type and delay time after the synthesis, the agglomeration size increased to flocculate. Au nanoparticles supported in chitosan showed the same shape as colloids and fractal aggregation was mostly distributed on the matrix.
Nanofiltración/ósmosis inversa en la separación de fármacos de efluentes
(2021) González, Enrique; Vera Cabezas, Luisa Mayra; Astudillo Alemán, Ana Lucía; Cruzat Contreras, Christian Américo; Solórzano, A.
Membrane separation processes can be an effective barrier against pharmaceuticals and other organic compounds present in water sources. This investigation presents the results of the separation of ciprofloxacin (CIPRO) and sulfamethoxazole (SULFA) in aqueous solution with nanofiltration membranes (NF) and reverse osmosis (OI) at a concentration in the feed of 5 mg / L and the influence of pH on separation mechanisms. With RO membranes, rejection was 100% for CIPRO and greater than 98% for SULFA at the studied pH. For the NF, the pH had influences on the separation of the SULFA, obtaining in the rejection 73.7% at pH 5 and at pH 7 and 9 greater than 94%. In the case of CIPRO, rejection percentages greater than 91% were obtained. The rejection obtained with the solution of the mixture of the two drugs shows no change since the percentages of rejections are very close to the results obtained in the study of the drugs separately. The transmembrane pressure did not influence the rejection of the drugs.
Low-cost crop waste biosorbent technology for removing toxics and pollutants from wastewater
(Springer, 2020) Vera Cabezas, Luisa Mayra; Cruzat Contreras, Christian Américo; Vanegas Peña, María Eulalia
Antibacterial and antifungal properties of electrospun recycled PET polymeric Fibers functionalized with zinc oxide nanoparticles
(2021) Cruzat Contreras, Christian Américo; Vázquez Ordóñez, Katherine Anabel; Vanegas Peña, María Eulalia; Arrué, Ramón Francisco; Novoa, Néstor; Vanegas Peña, Paúl Fernando
Currently, to reduce the environmental problems associated with plastic waste, methods are being sought to use this waste as raw materials in different applications, such as fibers. In addition, to improve these materials and provide different properties, nanoparticles (NPs) are incorporated. In the present work, polymeric fibers made of recycled polyethylene terephthalate (r-PET) from post-consumer water bottles, functionalized with 0%, 1.5%, 3% and 6% zinc oxide nanoparticles (ZnO-NPs) in function of r-PET weight, were elaborated to evaluate their antibacterial and antifungal characteristics. The ZnO-NPs were synthesized by the solvothermal method, obtaining particles with a mean diameter of 38.15 nm, while the fibers were obtained by electrospinning with a diameter range between 200–5000 nm. The functionalized fibers were carried out against Escherichia coli and Bacillus subtilis through the agar diffusion method, obtaining the highest inhibition halo at 6% w/w ZnO-NPs, being 26.5 mm and 34.25 mm, respectively. In addition, the same method was used to evaluate the antifungal activity of Penicillium s.p. and Fusarium graminearum, observing antifungal properties due to the presence of nanoparticles in the fibers.
Synthesis and aggregation study of tin nanoparticles and colloids obtained by chemical liquid deposition
(2009) Cruzat Contreras, Christian Américo; Arbiol, Jordi; Meléndrez, Manuel F; Cárdenas Triviño, Galo T; Díaz, Jordi
Tin colloids (Sn-Colls) and nanoparticles were synthesized by a chemical liquid deposition method (CLD). Sn0 was evaporated and codeposited with acetone, 2-propanol, and tetrahydrofurane vapors at 77 K to obtain colloidal dispersions. Sn-Coll were characterized by UV spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy, selected area electron diffraction, thermal analysis, infrared spectroscopy [Fourier transform infrared (FTIR)], and light scattering. TEM micrographs of tin nanoparticles (Sn-Nps) revealed a particle size distribution between 2 and 4 nm for the three solvents used in the synthesis. UV studies showed strong absorption bands in the UV region, suggesting that the Sn-Nps obtained by CLD exhibit quantum confinement and typical bands of plasmons corresponded to aggregated particles. Electrophoresis measurement indicated a significant tendency of particle aggregation along time, which was verified by light scattering studies. The diffraction patterns revealed phases corresponding to metallic tin and FTIR studies showed the interaction Sn-solvent in the metal surface by Sn-O bonds, indicating a solvatation of metallic clusters. Thermal analysis revealed a good thermal stability of Sn-Nps. The mechanism of tin nanoparticles formation was also examined.