Mostrando ítems 1-5 de 5

Análisis de gases desprendidos de residuos industriales de yuca (Manihot esculenta)

Albis Arrieta, Alberto Ricardo; Ortiz Muñoz, Ever; Piñerez Ariza, Ismel; Ariza Barraza, Cindy Skarlett; Díaz Durán, Ana Katherine (Corporación Universidad de la Costa, 2018-01-01)

Introducción: La pirólisis de residuos agroindustriales es una alternativa para generar combustibles líquidos de segunda generación.Objetivo: Determinar la cinética de la pirólisis de residuos industriales de yuca y de ...
Biosorption of neodymium (nd) from aqueous solutions using Spirulina platensis sp. strains

Lima, Eder Claudio; Pinto, Diana; Schadeck Netto, Matias; Simoes dos Reis, Glaydson; Silva Oliveira, Luis Felipe; Dotto, Guilherme Luiz (MDPI AGSwitzerland, 2022-10-28)

Rare earth elements such as neodymium (Nd) are important elements used mainly in developing new technologies. Although they are found in low concentrations in nature, they can be obtained by extracting solid samples such ...
Evaluación de la capacidad de remoción de plomo y cadmio en soluciones acuosas utilizando resinas de carbón mineral

Marín Castro, Nellys; Vásquez Frieri, Yessika (Universidad de la CostaIngeniería Ambiental, 2019)

In the present investigation, an alternative treatment for the removal of lead and cadmium from aqueous solutions by means of an adsorbent material made from modified mineral coal impregnated with carbon disulphide and ...
Preparation of alumina-supported Fe-Al-La composite for fluoride removal from an aqueous matrix

Gasparotto, Juliana M.; Pinto, Diana; de Paula, Natalie; Maraschin, Manoel; Dison S.P., Franco; Carissimi, Elvis; Foletto, Edson; Jahn, Sergio L.; Silva Oliveira, Luis Felipe; Dotto, Guilherme Luiz (Springer Science + Business MediaGermany, 2023)

Using groundwater for human consumption is an alternative for places with no nearby surface water resources. Fluoride is commonly found in groundwater, and the consumption of this water for a prolonged time in concentrations ...
Selective adsorption of gadolinium from real leachate using a natural bentonite clay

Dotto, Guilherme Luiz; Vieillard, Julien; Pinto, Diana; Lütke, Sabrina F.; Silva Oliveira, Luis Felipe; dos Reis, Glaydson S.; Lima, Éder C.; Dison S.P., Franco (Elsevier BVUnited Kingdom, 2023)

This article investigated the recovery of Gd3+ from real leachate of phosphogypsum (PG) using natural bentonite clay. Firstly, a detailed adsorption study was performed using synthetic Gd3+ solutions. Then, it was investigated ...

Envíos recientes

Análisis de gases desprendidos de residuos industriales de yuca (Manihot esculenta)
...
Albis Arrieta, Alberto Ricardo | 2018-01-01

Introducción: La pirólisis de residuos agroindustriales es una alternativa para generar combustibles líquidos de segunda generación.Objetivo: Determinar la cinética de la pirólisis de residuos industriales de yuca y de formación de productos.Metodología: Se estudió la pirólisis de residuos provenientes de la industria del almidón de yuca utilizando termogravimetría acoplada a espectrometría de masas. Los datos termogravimétricos fueron ajustados al modelo cinético de distribución de energías de activación, siendo necesario el uso de sólo un pseudocomponente.Resultados: La pirólisis de las muestras calentadas a velocidades inferiores a 30 K/min mostró valores de los parámetros cinéticos diferentes a los de la pirólisis de las muestras calentadas a velocidades superiores a 50 K/min, lo cual sugiere un cambio de mecanismo con la velocidad de calentamiento. Los valores obtenidos de los parámetros cinéticos de la pirólisis de los residuos estudiados se encuentran en el rango reportado de la literatura para otros tipos de biomasa. Se identificaron 23 relaciones m/z en los gases desprendidos de la muestra con suficiente relación señal/ruido. Las señales de espectrometría de masas seleccionadas fueron ajustadas con el modelo DAEM utilizando los parámetros cinéticos obtenidos con los datos termogravimétricos.Conclusiones: Se obtuvieron buenos resultados de ajuste con el modelo DAEM de un solo pseudocomponente para la mayoría de las relaciones m/z. La falta de ajuste para las relaciones m/z que no ajustaron se puede atribuir a reacciones secundarias en fase gaseosa.

LEER
Biosorption of neodymium (nd) from aqueous solutions using Spirulina platensis sp. strains
...
Lima, Eder Claudio | 2022-10-28

Rare earth elements such as neodymium (Nd) are important elements used mainly in developing new technologies. Although they are found in low concentrations in nature, they can be obtained by extracting solid samples such as phosphogypsum. Among the techniques, adsorption has been used successfully with several adsorbent materials. In this work, two strains of Spirulina platensis (LEB-18 and LEB-52) were employed as biosorbents for efficiently removing the Nd element from the aqueous media. Biosorption tests were carried out in a batch system, and the results of the biosorption kinetics showed that for both materials, the biosorption of Nd was better described by the Avrami model. Moreover, it could be considered that 80 min would be necessary to attain the equilibrium of Nd(III) using both biosorbents. The result of the biosorption isotherms showed that for both strains, the best-fitted model was the Liu model, having a maximum biosorption capacity of 72.5 mg g−1 for LEB-18 and 48.2 mg g−1 for LEB-52 at a temperature of 298 K. Thermodynamics of adsorption showed that for both LEB-18 and LEB-52 the process was favorable (∆G° < 0) and exothermic (∆H° −23.2 for LEB-18 and ∆H° −19.9 for LEB-52). Finally, both strains were suitable to uptake Nd, and the better result of LEB-18 could be attributed to the high amount of P and S groups in this biomass. Based on the results, a mechanism of electrostatic attraction of Nd3+ and phosphate and sulfate groups of both strains of Spirulina platensis was proposed.

LEER
Evaluación de la capacidad de remoción de plomo y cadmio en soluciones acuosas utilizando resinas de carbón mineral
...
Marín Castro, Nellys | 2019

In the present investigation, an alternative treatment for the removal of lead and cadmium from aqueous solutions by means of an adsorbent material made from modified mineral coal impregnated with carbon disulphide and sodium hydroxide was considered. The material used was chemically characterized, the effect of pH on removal, adsorption kinetics (using Lagergren and Ho and McKay models) and Langmuir and Freundlich isotherms were evaluated in order to evaluate the adsorption capacity of modified coal. The results of the characterization of the coal showed that it is of metallurgical type, for its high content of volatile material and low content of Sulphur, as well as of ashes that makes it effective for the combustion and generation of energy. Tests to evaluate the effect of pH on adsorption determined that the best removal of lead and cadmium was at pH 6, for both materials, with adsorption percentages of 99.75 % and 99.85% for lead and cadmium with modified carbon and 75% and 52.5 for lead and cadmium with unmodified carbon. Kinetic studies indicated that the adsorption process reaches equilibrium in 100 minutes with 19.95 mg/g for lead and 19.94 mg/g for cadmium, following the kinetic model of pseudo second order for both metals. The isothermal study showed that the adsorption of Lead and Cadmium in the modified carbon is better suited to a Freundlich isotherm. In addition, a laboratory scale application test was performed with industrial wastewater, where removal percentages of 99.11% and 92% of cadmium and lead, respectively, were found. This modification shows as a result a considerable increase in the adsorption of lead and cadmium with respect to coal, which indicates that this adsorbent is favorable for the removal of heavy metals.

LEER
Preparation of alumina-supported Fe-Al-La composite for fluoride removal from an aqueous matrix
...
Gasparotto, Juliana M. | 2023

Using groundwater for human consumption is an alternative for places with no nearby surface water resources. Fluoride is commonly found in groundwater, and the consumption of this water for a prolonged time in concentrations that exceed established limits by WHO and Brazilian legislation on water potability (1.5 mg L−1) can cause harmful problems to human health. For this reason, fluoride removal is an important step before water consumption. In this work, activated alumina was impregnated with Fe-Al-La composite and employed for the first time as an adsorbent for fluoride removal from an aqueous environment. XRD, SEM/EDS, FT-IR, and point of zero charge were used to characterize the prepared adsorbent. The adsorptive performance of adsorbent material was investigated by employing a 23-central composite design (CCD), and the obtained experimental conditions were pH = 6.5 and adsorbent dosage = 3.0 g L−1. A maximum adsorption capacity of 8.17 mg g−1 at 298 K and pH = 6.5 was achieved by Langmuir isotherm to describe the adsorption. The kinetic model that better described experimental data was Avrami, with the kav parameter increasing with the initial concentration from 0.076 to 0.231 (min−1)nav. The nature of adsorption was found to be homogeneous, and it occurs in a monolayer. The fluoride removal performance for the prepared adsorbent was higher than granular activated alumina, showing that supporting Fe-Al-La at the alumina surface increased its fluoride adsorption capacity from 16 to 42% at the same experimental conditions. Finally, the influence of co-existing ions Cl−, SO42−, and NO3− was evaluated in fluoride adsorption, and the material presented great selectivity to fluoride. Thus, Fe-Al-La/AA adsorbent is a promising material for fluoride removal from water.

LEER
Selective adsorption of gadolinium from real leachate using a natural bentonite clay
...
Dotto, Guilherme Luiz | 2023

This article investigated the recovery of Gd3+ from real leachate of phosphogypsum (PG) using natural bentonite clay. Firstly, a detailed adsorption study was performed using synthetic Gd3+ solutions. Then, it was investigated the clay performance in the real PG leachate. The characterization results indicate classical bentonite characteristics, such as rugosity and an SBET 91.3 m² g−1, with meso (Dp =3.82 nm) and macroporous (Dp =52.6 nm). In addition, it was identified that the major functional groups are hydroxyl and silicate, with the presence of organic matter. The initial pH solution effect indicates that the optimum removal of Gd3+ is at pH (6), attributing to the pHpzc being at 5.75 and the negatively charged surface above the pHpzc. The Avrami fractional order model was the most suitable for describing the experimental kinetic data. The Langmuir was the proper model for describing the adsorption isotherms, indicating that the Gd3+ forms a monolayer at the surface of the bentonite. The maximum adsorption capacity at pH 6.0 was 121.5 mg g−1. The thermodynamic parameters indicate that the adsorption is spontaneous, with a standard enthalpy change of − 92.30 kJ mol−1, indicating an ionic exchange, where the Gd3+ tends to be organized at the surface, according to the standard entropy change of − 206.0 J K−1 mol−1. The fixed bed adsorption test showed that Gd3+ could be adsorbed for up to 200 min without regeneration. Regeneration results show that the citric acid is more efficient in desorbing the Gd3+ from the bentonite, reaching up to 8 cycles without efficiency loss. Finally, the bentonite clay could selectively recover Gd3+ from the real PG leachate.

LEER

Listar por tema "Kinetics"

Análisis de gases desprendidos de residuos industriales de yuca (Manihot esculenta) ﻿

Biosorption of neodymium (nd) from aqueous solutions using Spirulina platensis sp. strains ﻿

Evaluación de la capacidad de remoción de plomo y cadmio en soluciones acuosas utilizando resinas de carbón mineral ﻿

Preparation of alumina-supported Fe-Al-La composite for fluoride removal from an aqueous matrix ﻿

Selective adsorption of gadolinium from real leachate using a natural bentonite clay ﻿

Envíos recientes

Análisis de gases desprendidos de residuos industriales de yuca (Manihot esculenta)

Biosorption of neodymium (nd) from aqueous solutions using Spirulina platensis sp. strains

Evaluación de la capacidad de remoción de plomo y cadmio en soluciones acuosas utilizando resinas de carbón mineral

Preparation of alumina-supported Fe-Al-La composite for fluoride removal from an aqueous matrix

Selective adsorption of gadolinium from real leachate using a natural bentonite clay

Análisis de gases desprendidos de residuos industriales de yuca (Manihot esculenta)

Biosorption of neodymium (nd) from aqueous solutions using Spirulina platensis sp. strains

Evaluación de la capacidad de remoción de plomo y cadmio en soluciones acuosas utilizando resinas de carbón mineral

Preparation of alumina-supported Fe-Al-La composite for fluoride removal from an aqueous matrix

Selective adsorption of gadolinium from real leachate using a natural bentonite clay