Synthesis and characterization of hybrid activated bentonite/alginate composite to improve its effective elimination of dyes stuff from wastewater (original) (raw)
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International Journal of Biological Macromolecules, 2018
Using the extrusion method, novel hybrid beads were prepared from natural bentonite and alginate. Alginate to clay ratios was varied (1/1; 1/2 and 1/3) and used to eliminate two dyes (methylene blue and Congo red).Adsorbents were characterized by Fourier transformed infrared spectroscopy, X-ray diffraction, Brunauer-Emmett-Teller method (BET) from N 2 adsorption-desorption isotherm at 77 K, and the point of zero charge (pH PZC). The adsorption of methylene blue and Congo red was studied according to different parameters. The results showed that isotherms were well described by the Langmuir model justifying monolayer and homogeneous adsorption. Kinetics were well followed the pseudo-second-order model.
Removal of Crystal Violet Dye by Adsorption Using Bentonite – Alginate Composite
Journal of Environmental and Chemical Engineering, 2017
The microwave rapid heating method was successfully applied to the production of bentonitealginate composite which is effectively used as a sorbent for dye removal. The irradiation method has been proven to assist effectively in the formation of sorbent pores that facilitate the permeation of dye solution. Three nanocomposite models were prepared by varied the mass of bentonite to a certain mass of sodium alginate. In this study, the adsorption performance of bentonitealginate nanocomposites were tested for the removal of crystal violet dye. The characterizations of the composites were conducted using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and nitrogen sorption methods The adsorption experiments were carried out in batch mode at three different temperatures (30, 50, and 70°C). The adsorption equilibria data were fitted by Langmuir and Freundlich isotherms. The nonlinear fitting coefficient R 2 indicates that the adsorption follows both the isotherm models well. The best adsorption capacity is showed by the composite prepared with the highest proportion of bentonite mass. The high-temperature promotes the adsorption capacity of the composite, where at 70°C the adsorption capacity is reached 601.9339 mg/g (Langmuir parameter, q max ) or 36.3399 (mg/g)(L/mg) −n (Freundlich parameter, K F ). The adsorption kinetic results follow the pseudo-second-order model better than the pseudo-first-order which indicated by higher R 2 values (0.9209 to 0.9916). As indicated by the thermodynamic properties, the adsorption process is controlled by chemisorption.
Advanced Materials Research, 2014
This study reports on the modification of natural bentonite by a cationic polyelectrolyte, which is a lignin-based aldehyde-ketone resin, and the application of this modified clay as adsorbent in the removal of reactive dyes from aqueous solution. Modified bentonite was characterized by IR and zeta-potential test, its dye removal performance was evaluated. Results show that intermolecular interaction and electrostatic attraction between dyes and adsorbent are responsible for the adsorption behavior. The removal of reactive dyes increased with increasing temperature and the optimum pH range was 4.0-6.5. The negative values of ΔG reflected the spontaneous adsorption and the values of ΔH showed that it was a combination of chemical and physical adsorption. Equilibrium adsorption data fitted well to Langmuir isotherm and the adsorption capacity for reactive red and reactive blue was 125.0 and 159.2 mg/g, respectively.
Alginate-bentonite beads for efficient adsorption of methylene blue dye
Euro-Mediterranean Journal for Environmental Integration, 2020
In this study, alginate/bentonite adsorbent beads (Alg/Ben) were prepared by encapsulating natural bentonite (Ben) in calcium alginate (Alg). Different Alg/Ben ratios were applied during bead preparation, yielding beads denoted Alg-Ben1 (1/1 w/w), Alg-Ben2 (1/2 w/w), and Alg-Ben3 (1/3 w/w), respectively. These adsorbents were characterized by Fourier-transform infrared spectroscopy and X-ray diffraction. The adsorption of methylene blue (MB) from aqueous solution on the Alg/ Ben beads was investigated as a function of several parameters, including initial MB concentration and contact time. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium adsorption isotherms, and they were found to be well described by the Langmuir model. Encapsulating Ben in Alg led to a substantial increase in maximum amount of methylene blue adsorbed by Ben, from 345 to 1237 mg g −1. The results showed that, among the three types of Alg/Ben beads, Alg-Ben1 presented the greatest MB adsorption capacity. A kinetic study indicated that the adsorption was governed by second-order kinetics.
The Journal of Pure and Applied Chemistry Research
Abundant and inexpensive Indonesian natural bentonite was activated by thermal activation at 500 o C for removal of procion red dye as one of the most used synthetic dye in the traditional songket fabric production around Palembang city. Activated bentonite product was characterized by FT-IR, XRD, and thermal analysis. The adsorption process was conducted in batch adsorption system by applying various adsorption parameter condition including, initial pH condition, contact time, and initial dye concentration. The activated bentonite characterization indicates that during the activation process, the structure of the original bentonite was not changed significantly and the result of the thermal analysis revealed that thermal activation at 500 o C was draining the water content without destructing the silica-alumina framework of bentonite. The adsorption kinetics study shows that the procion red adsorption into the activated bentonite follows the pseudo-second order kinetic model. The isotherm adsorption study revealed that procion red adsorption into activated bentonite adapted the Langmuir adsorption isotherm.
Application of activated bentonite for the removal of direct and reactive dye from aqueous solutions
Chemical Industry and Chemical Engineering Quarterly
The aim of this study was to determine adsorptive properties of acid activated bentonite clay for the removal of Direct Red 173 (DR 173) and Reactive Red 22 (RR 22) dyes from aqueous solutions. Raw and modified clay were characterized by the following methods: Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM). The efficiency of activated clay adsorption was investigated depending on process parameters: the adsorbent dose, pH, temperature, initial dye concentration, and contact time. Experimental data were analyzed by Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm as well as kinetic models of pseudo-first order, pseudo-second order and intra-particle diffusion. The process of dye adsorption was best described by Langmuir, Temkin, and Dubinin-Radushkevich isotherm (R2 > 0.97). Pseudo-second order model (R2 > 0.99) had the highest correlation with the obtained kinetic results. The positive valu...
2021
The present work focuses on intercalating a natural bentonite with an organo-inorganic specieobtained by hydrolysis of 3-aminopropyltrimethoxysilane in order to improve its adsorption capacity. The material obtained is used in the deppolution of water polluted by dyes. Methylene blue is chosen as a model pollutant. In order to be able to characterize this clay after modification, we used several physico-chemical and mineralogical analysis techniques such as X-ray diffraction, infrared spectroscopy, chemical and thermal analysis. The cationic exchange capacity was determined as well. In addition, with a view to optimization, the effects of several adsorption factors, including time, pH, dye concentration, and masse of clay on the adsorption capacity of methylene blue by the adsorbent were assessed as well. The results of this study showed that Langmuir isotherm is the model which best characterized the adsorption of methylene blue by the developed adsorbent (Bent-APTES) with a capaci...
Journal of Saudi Chemical Society, 2018
In this study, the adsorption removal of an anionic dye (Congo red) by a local bentonite before and after modification was studied. The modification of the bentonite was made by organophilisation using surfactant (HDTMA) and by pillaring process to obtain a bentonite with Ti pillars and with mixed pillars of Fe/Al. The various synthesized materials are characterized by different techniques such as DRX, MET, N 2 adsorption-desorption, Zeta potential measurement. Results show the development of the texture and the structure of the bentonite after modification. The various adsorbents synthesized show an increase in the adsorption capacity of Congo Red compared to the initial bentonite.Adsorption isotherms are described by the Langmuir model in all cases except that for Ti pillared bentonite, the Freundlich model is more suitable. Pseudo-second order is better for describing the adsorption process. Also, regeneration of the adsorbent is approached in this study by photochemical way and the results show a total regeneration of the adsorbent.
Thermal and chemical modification of bentonite for adsorption of an anionic dye
Advances in Environmental Technology (AET), 2018
Raw bentonite (RB), a known low-cost versatile clay was used as an adsorbent. RB was treated thermally and chemically to increase its adsorption capacity. For thermal treatment (TTB), the bentonite was heated at 400 °C for 60 min, and for the chemical modification, its surface was treated by cetyltrimethylammonium bromide (CTAB) to prepare organo-modified bentonite (CTAB-B). The removal of Congo red dye (CR) from aqueous solution was investigated in the batch mode. The prepared adsorbents were characterized by SEM, BET, and FTIR analyses. The effects of various experimental parameters such as contact time, pH, adsorbent dosage, dye concentration and temperature were investigated. The obtained results were in good agreement with the Langmuir isotherm model, and the maximum adsorption capacity of RB, TTB and CTAB-B was 43.1, 55.86 and 116.28 mg/g, respectively. The adsorption kinetic was better described by the pseudo-second order kinetic model. The results showed that thermally or chemically modified bentonite could be proposed as a low-cost adsorbent for the removal of CR from water.