Modelling of the Adsorption Kinetics of Chromium (Vi) Using Waste Biomaterials

Herrera-Barros

2019

Rev. Fac. Ing.

Chromium (Cr(VI)) presents carcinogenic and mutagenic effects in living beings. Biosorption is an alternative to conventional technologies for the treatment of waste water. The aim of this study was to assess the use of corncob and orange peels modified with citric acid and calcium chloride, respectively, for the removal of Cr(VI) using a batch system taking into account pH and particle size. Biomaterial were characterized using an elemental and chemical analysis, and FTIR, in which was evidenced the presence of hydroxyl, carbonyl and carboxyl groups, belonging to the cellulose and lignin that are attributed for the presence of active centers which intervene in the adsorption process. Adsorption experiments through batch system were performed using a solution of potassium dichromate at 100 ppm, 150 rpm, varying pH (2, 3, 4 and 6) and particle size (0.355, 0.5 and 1 mm). From de results was found that maximum removal percentage was obtained at pH 2 and particle size of 0.355 using corncob and orange peels. Final concentration of Cr(VI) was determined by using the standard method ASTM D1687-02 with 1,5-diphenylcarbazide at 540 nm. Adsorption kinetics and isotherms were assessed with the best conditions found, in which the experimental data was adjusted to the Pseudo-second order and Freundlich models, respectively. R2 value greater than 0.95 suggests that the process is controlled by a chemical reaction leading the formation of multilayers. The performance of the biomass in terms of q0 was found to be: corncob>orange peels>corncob modified>orange peels modified.

Section: Discussionmentioning

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Assessment of Chemically Modified Lignocellulose Waste for the Adsorption of Cr (VI)

Herrera-Barros

2019

Rev. Fac. Ing.

“…The active sites of absorption are occupied first by strong bonds, and this force decreases as they are occupied by the ions [54], [55]. The value of Freundlich's constant n (Table 4), is not in the range 1-10 which indicates that the chemical bonds formed between the ions and adsorbent are weak [54], [56], [57]. From equilibrium data to the Dubinin-Radushkevich model, a good fit was found for the Ni (II) and Pb (II) isotherm, with an R 2 higher than 0.98 in both cases and a qmax close to the experimental one.…”

Section: Adsorption Equilibriummentioning

confidence: 99%

Adsorption in a binary system of Pb (II) and Ni (II) using lemon peels

Rev.Fac.Ing.Univ.Antioquia

Sierra-Ardila

Meza-Acuña

et al. 2020

The elimination of pollutants in water sources is a widely studied issue with the purpose of preserving the environment. In this work, the use of lemon peel (citrus lemon) as a bio-sorbent in the removal of Pb (II) and Ni (II) is studied, varying the temperature, adsorbent dose, and particle size. The materials were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) analysis, to determine the bio adsorbent’s physicochemical properties. FTIR and EDS techniques confirmed the precipitation of ions on the adsorbent after the adsorption process. It was found that the optimal conditions according to the Response Surface Methodology (RSM) are: particle size for Ni (II) of 1 and 0.355 mm, adsorbent dose 0.077 g and 0.117 g, and temperatures of 34 and 45 ºC, for Pb (II) and Ni (II), respectively. The results reported that the Dubinin-Radushkevich isotherm and the pseudo-second-order model are more in line with the experimental data, suggesting that the adsorption process is driven by physisorption and occurs in multilayers. Thermodynamic parameters suggest that the process is exothermic for Ni (II) and endothermic for Pb (II), and irreversible. The binary study showed that there is no competition for active sites between the ions.

“…On the other hand, the Colombian regulation about the punctual discharge to bodies of marine water establishes that the Cr (VI) discharge concentrations must be between 0.2-0.5 ppm, under Resolution 0883 of May 2018 [8]. However, concentrations of this metal could reach up to 450 ppm, for industrial effluents [9,10]. Among the various physicochemical processes, adsorption is one of the most effective and easy to implement methods [11,12].…”

mentioning

confidence: 99%

Cr(VI) biosorption: Effect of temperature, particle size and bed height

Ortega-Toro

2020

redin

The present work aimed to evaluate the effect of temperature, particle size and bed height of the chromium (VI) adsorption process using plantain peels in a continuous system. The experiment was carried out on a packed bed column, adjusting the feed temperature of the solution with a REX-C100 controller coupled to a type K thermocouple. The initial concentration of Cr (VI) was set at 100 ppm, the pH at 2 and the feed rate of 0.75 mL/s. The analyses were performed by UV-Vis spectroscopy using the colourimetric method of 1.5-diphenylcarbazide. The material was characterized by infrared spectrometry by Fourier Transforms (FTIR), from this analysis, it was determined that the OH and NH2 functional groups are the main responsible for the formation of complexes with the cations in solution. Also, it was established that only the particle size is statistically significant. According to the response surface analysis, the optimum conditions of the process were 353.15 K, a particle size of 0.819 mm and a bed height of 67.768 mm. From the thermodynamic study of the process, it is established that it is endothermic and the chemical adsorption prevails in it. The results obtained in the process modelling suggest that Dose-Response can be used reliably to scale the process.