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- MakaleYalnız künye2024Adsorption of Azocarmine G dye on H2SO4-modified acacia sawdust
Duran, Celal; Ozeken, Sengul Tugba; Camoglu, Aslihan Yilmaz; Ozdes, Duygu
Presence of hazardous dyes in water cause considerable risks to the human health and environment due to their potential toxicity and ecological disruptions. Therefore, in the present research, to suggest an alternative method for the retention of toxic Azocarmine G (ACG) dye from aqueous media, natural and H2SO4-modified acacia sawdust were performed for the first time as low-cost and efficient adsorbents. Based on batch experiments, it was determined that the best conditions for the developed dye retention process were an initial pH of 2.0 and an equilibrium time of 240 min. Analysis of the data using both pseudo-first order and pseudo-second order kinetic models showed that the retention of ACG onto the adsorbents predominantly occurred through chemical adsorption. Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models were employed to provide insights into the interaction between the adsorbate and adsorbent and the mechanism of the adsorption process. Maximum monolayer adsorption capacities of natural and H2SO4-modified acacia sawdust were determined as 28.01 and 64.90 mg g-1, respectively by Langmuir isotherm model. Results of the study clearly indicated that the modification of acacia sawdust with H2SO4 leads to a substantial increase in the adsorption performance of anionic dyes.
- MakaleAçık Erişim2023Adsorption Behaviour of EDTA Modified Magnetic Fe3O4 Coated Brewed Tea Waste on Cr(VI) Removal
Yilmaz Camoglu, Aslihan; Ozdes, Duygu; Duran, Celal
The study focused on fabricating a novel magnetic Fe3O4 loaded and EDTA modified brewed tea waste (TW-Fe3O4-EDTA) as a cheap, environmentally friendly, and efficient adsorbent for the removal of Cr(VI) ions from aqueous medium in a batch system. Characterization of the prepared adsorbent was performed with different techniques. Adsorption experiments were implemented at different conditions including initial solution pH (1.0–7.0), equilibrium time (1–480 min), adsorbent dosage (1.0–20.0 g L–1), and initial Cr(VI) concentration (50–1000 mg L–1). The optimum adsorption performance was observed at pH 2.0 with 120 min of contact time. Maximum adsorption capacity of 114.9 mg g–1 was acquired for TW-Fe3O4-EDTA which is much higher than the recently developed adsorbents for Cr(VI) removal. Adsorption process was well explicated by Freundlich isotherm model and the adsorption rate is described in accordance with pseudo-second order kinetic model. It was observed that common salts did not have a notable influence on Cr(VI) adsorption. The results of the study indicated that TW-Fe3O4-EDTA can be applied as an effective adsorbent in heavy metal removal as an alternative to many expensive adsorbents available in the literature.
- MakaleAçık Erişim2023Enhancement of adsorptive removal efficiency of an anionic dye from aqueous solutions using carboxylic acid-modified mulberry leaves: Artificial neural network modeling, isotherm, and kinetics evaluation
Duran, Celal; Ozeken, Sengul Tugba; Camoglu, Aslihan Yilmaz; Ozdes, Duygu
Natural mulberry leaves and carboxylic acid-modified mulberry (Morus alba L.) leaves were used for the first time to scrutinize the effects of modification on the retention efficiency of an anionic dye (Remazol Brilliant Blue R (RBBR)) from aqueous solutions to suggest an economical and promising adsorbent for the treatment of dye-contaminated water. The characterization of the adsorbents was accomplished through common techniques including SEM, FTIR, and pHpzc determination. Several parameters studied in batch experiments pointed out that the initial pH of 2.0 and the contact time of 240 min were optimum conditions for all the developed RBBR uptake processes. An artificial neural network (ANN) model was applied to formulate a forecast model for the uptake efficiency of RBBR. The experimental data were assessed by different kinetic and isotherm models to explain the mechanism of the developed processes in more detail. Maximum monolayer adsorption capacities of natural mulberry leaves and acetic acid-, citric acid-, and oxalic acid-modified mulberry leaves were determined as 64.5, 95.2, 84.8, and 91.7 mg g1, respectively, by the Langmuir isotherm model. These results demonstrated that the modification with carboxylic acids significantly increases the anionic dye adsorption capacity of the mulberry leaves.
- MakaleYalnız künye2015Equilibrium, kinetics, and thermodynamic evaluation of mercury (II) removal from aqueous solutions by moss (Homalothecium sericeum) biomass
Ozdes, Duygu; Duran, Celal
In the present research, Homalothecium Sericeum was utilized for the first time as an effective and readily available adsorbent in removal of Hg(II) ions from aqueous solutions through a batch adsorption technique. The effects of initial solution pH, contact time, initial Hg(II) and adsorbent concentration, temperature, and ionic strengths were evaluated on the removal efficiency of Hg(II) ions, after being characterized of H. sericeum by different techniques. The maximum Hg(II) adsorption was obtained as 128.2 mg g-1 at initial pH 6.0 with an equilibrium time of 60 min, adsorbent dosage of 5.0 g L-1 and initial Hg(II) concentration range of 50-750 mg L-1. The adsorption behaviors of Hg(II) ions onto H. sericeum were investigated in terms of kinetics (pseudo-first order, pseudo-second order, and intraparticle diffusion models), isotherms (Langmuir, Freundlich, and Dubinin Radushkevich models), and thermodynamics evaluation. Both the Langmuir and Freundlich isotherm models were found to be suitable to describe the adsorption equilibrium while the adsorption kinetics followed by the pseudo-second order model. Thermodynamic parameters including the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes indicated that the adsorption of Hg(II) ions onto H. sericeum was feasible, spontaneous, and endothermic in nature.