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Showing 3 results for Dashtizadeh

Davoud Balarak, Mohadeseh Dashtizadeh, Hajar Abasizade, Marzieh Baniasadi,
Volume 4, Issue 2 (6-2018)

Background: Dyes are among the most hazardous chemical compounds, which are found in industrial effluents. The removal of dyes before the discharge of wastewater to the environment could reduce these environmental hazards. The present study aimed to evaluate the efficiency of cetyltrimethylammonium bromide-modified bentonite (CTAB-MB) surfactant in the adsorption of acid blue 80 (AB80) dye.
Methods: This experimental study was conducted using a shaker (100 rpm) at room temperature and fixed pH of 7 using conical flasks (200 ml) containing the dye solution (100 ml) to assess the adsorption conditions. In addition, five concentrations of the reactive blue dye were prepared to evaluate the effects of the initial dye concentration on adsorption. 
Results: The experimental data indicated that the AB80 removal procedure was fitted with the Langmuir isotherm. The Langmuir adsorption capacities (qe) were 38.15 and 21.76 mg/g for 1 and 2 g/l of the adsorbent, respectively. Moreover, three kinetic models were selected to fit the kinetic data, including the pseudo-first-order and pseudo-second-order models and intra-particle diffusion. AB80 was fitted with the pseudo-second-order model at all the concentrations. 
Conclusion: According to the results, CTAB-MB was an affordable alternative to the removal of dyes from industrial wastewater.

Davoud Balarak, Mohadeseh Dashtizadeh, Mohadeseh Zafariyan, Masomeh Sadeghi,
Volume 4, Issue 4 (12-2018)

Background: Nowadays, the development of new materials is emergent that can be used in the adsorption process to remove dyes from the aquatic environment. Therefore, in this study, the performance of raw Kaolin as a low cost adsorbent was evaluated in removing Direct Blue 71 (DB71) dye from aqueous solutions.
Methods: For investigating the adsorption, various parameters were optimized and data were adjusted to four isotherm models: Freundlich, Dubinin–Radushkevich, Langmuir and Temkin, in order to determine the one presenting the best adjustment to the experimental data. Moreover, the kinetics study for adsorption was evaluated using diffusion, pseudo-first-order kinetic and pseudo-second-order kinetic models.
Results: The results revealed that at the DB71 concentration of 10 mg/L, adsorbent dose of 2.5 g/L, and contact time of 75 min, the DB71 removal reached 98.5%. Adsorption data fitted best into the Langmuir and D-R adsorption isotherms. The maximum monolayer adsorption capacity was 36.41 mg/g. The pseudo second order kinetics best described the kinetics of the adsorption system.
Conclusion: It was revealed that Kaolin could be applied for DB71 dye removal from solution samples with the adsorption capacity of 36.41 mg/g and thus could be used as a low-cost and effective adsorbent.

Davoud Balarak , Hossein Ansari, Mahdethe Dashtizadeh, Maryam Bazi,
Volume 5, Issue 3 (9-2019)

Background: Phenolic compounds are an important group of pollutants in industrial wastewater, which must be treated before disposal into water resources. The present study aimed to use synthesized graphene oxide (SGO) to remove bisphenol A (BPA) from aqueous solutions.
Methods: Graphene oxide was synthesized using Hummers' method, and BPA adsorption was assessed as a function of solution pH, contact time, adsorbent dosage, and initial BPA concentration using the batch method. Isotherms and kinetic evaluation of dye adsorption was performed using the equilibrium data.
Results: Adsorption was rapid and strongly dependent on pH and adsorbent dosage, reaching the peak at the pH of 7 and adsorbent dosage of 0.8 g/l. BPA removal efficiency at the initial concentration of 10 mg/l was 98.8 ± 0.62%. Analysis of the experimental isotherm data using the Langmuir-Freundlich and Temkin models indicated that the removal process followed the Langmuir isotherm, while the adsorption kinetics followed the pseudo-second-order kinetic model. The maximum adsorption capacity was calculated by Langmuir fitting and determined to be 58.12 ± 1.14 mg/g.
Conclusion: According to the results, SGO could be employed as an effective agent for the removal of BPA from aqueous solutions.

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