Adsorption Performance of Zeolite for the Removal of Congo Red Dye: Factorial Design Experiments, Kinetic, and Equilibrium Studies

Abstract

In the present research, zeolite is used for the removal of toxic Congo red dye from water solution. The effects of different operating conditions such as hydrogen potential (pH), contact time (time), zeolite dose (D), initial dye concentration (C0), and ionic strength (I) are investigated for Congo red adsorption under batch mode. It was found that the adsorption process was greatly affected by the initial pH of the dye solution. The removal efficiency decreased from 97.68 to 5.22% when the pH varied from 3 to 5; thus, acidic conditions clearly improve Congo red adsorption on zeolite. At pH 3, an increase in C0 and I and decrease in D resulted in an increase in the adsorption capacity qe. The effects of these three parameters and their interactions were also investigated using the 23 full factorial design experiments approach where qe was chosen as the response. The results obtained from this method followed by the analysis of variance and the Student’s t-test show that, the influence of these parameters on dye adsorption process are in the order I < C0 < D. The kinetic studies revealed that adsorption follows a pseudo-second-order kinetic model. The adsorption isotherms experimental data were analyzed using the Langmuir, Freundlich, and Temkin isotherms models. The Freundlich isotherm was the best-fit model to the experimental data. The fitting of kinetics and isotherm models was evaluated by using non-linear modeling, R2, MSE, and RMSE.

Preparation of cellulose-based composite hydrogels for the removal of methylene blue

“…The adsorption isotherms describe the interactive behavior of the amount of adsorbate adsorbed on the surface of the adsorbent and the residual amount in the solution, until reaching a dynamic equilibrium at a constant and defined temperature. 42 To characterize the MB adsorption process, the Langmuir (equation (7)), Freundlich (equation (8)), and Temkin (equation (9)) adsorption isotherm models were used. In addition, the Langmuir isotherm’s value (equation (10)), denoted as bold-italicRbold-italicL, was used.where bold-italicCbold-italice (mg L −1 ) is the concentration of the adsorbate at equilibrium; bold-italicqbold-italice (mg g −1 ) is the adsorbed amount at equilibrium; bold-italicqbold-italicmax (mg g −1 ) is the maximum adsorption capacity; bold-italicKbold-italicL (L mg −1 ) is the Langmuir constant; bold-italicKbold-italicF (mg g −1 (L mg −1 ) 1/n ) is the Freundlich constant; 1/n is the adsorption intensity or surface heterogeneity; R (J mol −1 K −1 ) is the universal gas constant; T (K) is the temperature; bold-italicbbold-ital...…”

“…The adsorption isotherms describe the interactive behavior of the amount of adsorbate adsorbed on the surface of the adsorbent and the residual amount in the solution, until reaching a dynamic equilibrium at a constant and defined temperature. 42 To characterize the MB adsorption process, the Langmuir (equation ( 7)), Freundlich (equation ( 8)), and Temkin (equation ( 9)) adsorption isotherm models were used. In addition, the Langmuir isotherm's value (equation ( 10)), denoted as R L , was used.…”

An Eco-Friendly Adsorbent Based on Bacterial Cellulose and Vermiculite Composite for Efficient Removal of Methylene Blue and Sulfanilamide

“…For instance, Prof. Imessaoudene’s group prepared activated carbon from date stones by chemical activation with phosphoric acid and used it for the removal of gallic acid. They also used zeolite, a low-cost, eco-friendly, and sustainable material to remove malachite green, MB and toxic Congo red dye [ 18 , 19 , 20 , 21 ]. Kyzas et al, utilized low-cost natural textile fibers as adsorbents to remove basic dye from synthetic effluents [ 22 ].…”

Preparation and Characterization of Fe3O4/Poly(HEMA-co-IA) Magnetic Hydrogels for Removal of Methylene Blue from Aqueous Solution

“…Among all these methods, the adsorption technique is usually considered efficient, non-toxic, environmentally friendly, and simple to remove pollutants from wastewater [14]. For this reason, in the last years, various materials such as activated carbon, mineral clay [15], metal oxide particles [16], graphene oxide [17], silica [18][19][20], zeolites [21,22], hydrogels [23,24], etc., have been used in recent years for the removal of dyes from wastewater by the application adsorption technique. Hydrogels are crosslinked polymers with three-dimensional networks, which are widely used to remove environmental pollutants, and unlike other adsorbents, hydrogels adsorb pollutants in a highly porous network [25].…”