Tartrazine Removal from Aqueous Solution by HDTMA-Br-Modified Colombian Bentonite

Abstract

The effect of pH, ionic strength (NaCl added), agitation speed, adsorbent mass, and contact time on the removal of tartrazine from an aqueous solution, using an organobentonite, has been studied. A complete factorial design 32 with two replicates was used to evaluate the influence of the dye concentration (30, 40, and 50 mg/L) and amount of adsorbent (25, 35, and 45 mg) on decolorization of the solution. Experimental data were evaluated with Design Expert® software using a response surface methodology (RSM) in order to obtain the interaction between the processed variables and the response. pH values between 2 and 9, stirring speed above 200 rpm, and contact time of 60 min did not have a significant effect on decolorization. The optimum conditions for maximum removal of tartrazine from an aqueous solution of 30 mg/L were follows: pH = 6.0, NaCl concentration = 0.1 M, stirring speed = 230 rpm, temperature = 20°C, contact time = 60 min, and the organobentonite amount = 38.04 mg. The equilibrium isotherm at 20°C was analyzed by means of the Langmuir and Freundlich models, and the maximum adsorption capacity obtained was 40.79 ± 0.71 mg/g. This adsorption process was applied in a sample of industrial wastewater containing tartrazine and sunset yellow, having obtained a decolorization rate higher than 98% for both dyes. These results suggest that organobentonite is an effective adsorbent for the removal of anionic dyes from an aqueous solution.

Adsorption of Cr(VI) in Aqueous Solution Using a Surfactant-Modified Bentonite

“…e modification of the bentonite with the quaternary ammonium salt caused an increase in the basal spacing (d 001 ) of the layers from 1.6 nm to 2.1 nm brought about by HDTMA + cation intercalation. Macías-Quiroga et al [16] and Otavo-Loaiza et al [19] have reported similar basal spacing values for this bentonite and the bentonite modified with HDTMA-Br. e increase in the interlayer spacing indicates that the HDTMA + cations intercalated in the interlamellar space were arranged in the form of a pseudo-trimolecular layer [20].…”

“…e organobentonite was prepared by cationic exchange between the bentonite homoionized with sodium (CEC of the Na-Bent of 63.02 meq/100 g) and a cationic organic surfactant, hexadecyltrimethylammonium bromide (HDTMA-Br). e proportion of the surfactant used in the synthesis of organobentonite was 1.5 times the proportion of cation exchange capacity of sodium bentonite, a value recommended in literature [18], with a procedure similar to that used in a previous study [19]. For this, 20 g of Na-Bent was added to 500 mL of distilled water, and the suspension was stirred for 12 h to generate the swelling of the bentonite, and then the suspension was added with 7.03 g of HDTMA-Br (dissolved in 100 mL of distilled water) and the mixture was stirred for 24 h. e organobentonite (denoted as HDTMA-Bent) was separated by centrifugation and washed repeatedly until a negative bromide test was obtained with 0.1 M of AgNO 3 .…”

Adsorption of Azo-Anionic Dyes in a Solution Using Modified Coconut (Cocos nucifera) Mesocarp: Kinetic and Equilibrium Study

“…The E parameter of the Dubinin-Radushkevich model is higher for MCC (310.65 KJ/mol) than CC (42.229 KJ/mol), indicating that the ion exchange process is more elevated in modified cellulose than in natural cellulose [35]. It has been previously reported for the removal of tartrazine that the Freundlich model is the one that best describes the process, using bentonite modified with hexadecyltrimethylammonium bromide [23] and activated carbon from Lantana camara [1]; while the use of activated carbon from Moringa [25] was found in Langmuir to be a better fitting.…”

“…The adsorption equilibrium has been studied using isotherms, in order to identify how the analyte molecules in question are distributed between the liquid phase and the solid phase when the adsorption process reaches an equilibrium state [21]. The data used to obtain isotherms can be fitted by different models to study the nature of the process and can be used to compare the efficiency [22,23]. The adsorption equilibrium of Congo Red and Methylene Blue (MB) on activated carbons from ashitaba residues and walnut shells modified with Zinc Chloride has been investigated, finding that the bioadsorbents from ashitaba residues showed selectivity for CR reaching a maximum adsorption capacity of 632.13 mg/g, indicating their selectivity for the material; a maximum MB adsorption capacity of 400.11 mg/g was achieved on walnut shell biochar [24].…”

Preparation and characterization of low-cost adsorbents for the efficient removal of malachite green using response surface modeling and reusability studies

“…For example, reusing AC requires regeneration, which is costly and limits its large-scale application in wastewater treatment. In addition, some adsorbents are effective against a limited number of dyes and are difficult to separate from treated water 21 . Reference 22 focused on the immobilization of horseradish peroxidase onto supports such as polyamide-6 electrospun fibers, which were used for the decolorization of reactive black 5 and malachite green textile dyes from solutions imitating polluted sea waters and reached over 70%.…”