Sürdürülebilir Kalkınma Amaçları
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- MakaleYalnız künye2023Characterization of the Adsorption Mechanism of Cadmium(II) and Methylene Blue upon Corncobs Activated Carbon
Gundogdu, Ali; Bozbeyoglu, Pinar; Imamoglu, Mustafa; Baltaci, Cemalettin; Duran, Celal; Bulut, Volkan N.
A promising new activated carbon (AC) was produced from corncobs (CCs) by boric acid-based chemical activation to remove methylene blue (MB) as an organic pollutant and cadmium ions (Cd2+) as an inorganic pollutant from aqueous solutions. After the produced activated carbon (CCs-AC) was characterized, the adsorption mechanism of CCs-AC, which is one of the most interesting topics in the literature, was the primarily focus. The possible adsorption mechanisms of Cd2+ and MB on CCs-AC from aqueous solutions are discussed with respect to pH, thermodynamic values, and regeneration parameters. The results show that the adsorption of Cd2+ on CCs-AC was favorable at pH values higher than 4. In contrast, the adsorption process was almost pH-independent for MB. Variation of pH showed that the adsorption of Cd2+ on CCs-AC primarily occurs by electrostatic interaction. However, MB adsorption may also involve pi-pi dispersion forces and partial hydrogen bonding. The Cd2+ adsorbed on CCs-AC was quantitatively desorbed by HCl, whereas MB was not desorbed quantitatively by any solution. While a temperature increase has a positive effect on the adsorption of both methylene blue and Cd2+, the thermodynamic results show that MB adsorption is primarily chemisorption (Delta H of 24.28 kJ/mole), while Cd2+ adsorption is mostly physisorption (Delta H of 7.20 kJ/mole). Using Langmuir adsorption isotherms, the MB adsorption capacity of CCs-AC, which primarily has a microporous structure, was 0.88 mmol/g, while the Cd2+ adsorption capacity was 1.28 mmol/g.
- MakaleYalnız künye2018Adsorption of Cu(II) ions from aqueous solution by hazelnut husk activated carbon prepared with potassium acetate
Imamoglu, Mustafa; Ozturk, Asuman; Aydın, Şeyma; Manzak, Aynur; Gündoğdu, Ali; Duran, Celal
Hazelnut husk (HH), an agricultural waste, was converted to carbonaceous material by chemical activation using potassium acetate. The produced activated carbon (KAHHAC) was characterized by FTIR, SEM, N2 adsorption–desorption experiments, CHN elemental analysis, and determination of moisture, ash, and point of zero charge. KAHHAC was used for the batch adsorption of Cu(II) ions from aqueous solutions. Optimum pH and contact time were found to be 5.0 and 240 minutes, respectively. The adsorption equilibrium data were described well by the Langmuir equation providing 105.3 mg g−1 Cu(II) adsorption capacity. The pseudo-second-order model successfully described the kinetic of Cu(II) adsorption by KAHHAC. The adsorbed Cu(II) onto KAHHAC was completely desorbed by 0.5 M nitric acid. In conclusion, HH activated carbon (AC) produced by the potassium acetate activation method is a very useful and efficient sorbent material for the removal of Cu(II) from aqueous solution.
- MakaleYalnız künye2013Physicochemical characteristics of a novel activated carbon produced from tea industry waste
Gundogdu, Ali; Duran, Celal; Senturk, H. Basri; Soylak, Mustafa; Imamoglu, Mustafa; Onal, Yunus
Tonnes of waste are generated during tea production in Turkey, one of the black tea producing countries in the world. These wastes are not used for any purposes throughout industrial sector. The objective of this study is to bring in economic value to waste materials by producing activated carbons from wastes of a tea plant and to characterize their physicochemical properties. Three types of activated carbons were produced by chemical activation using zinc chloride from tea industry wastes (TIW). Mesoporous structure and surface area rise as the ratio of ZnCl2/TIW increases. When the ratios of ZnCl2/TIW were selected as 1/2:1, 1:1, and 2:1, mesoporous activated carbons are found in the percentages of 10.9%, 39.9% and 77.7% with BET surface areas of 706, 1066 and 1141 m(2) g(-1), respectively. The resultant activated carbons were characterized by analyses of proximate-ultimate, FT-IR, SEM, TGA, methylene blue-iodine numbers, and surface functional groups. (C) 2013 Elsevier B.V. All rights reserved.
- MakaleAçık Erişim2012Dehydrated hazelnut husk carbon: A novel sorbent for removal of Ni(II) ions from aqueous solution
Sivrikaya, Sezen; Albayrak, Sinem; Imamoglu, Mustafa; Gundogdu, Ali; Duran, Celal; Yildiz, Hulya
The present study has been performed to examine the adsorption ability of novel sorbent dehydrated hazelnut husk carbon (DHHC) towards Ni(II) ions from aqueous solution using the batch adsorption technique. The effective factors such as initial pH of the aqueous solution, contact time, initial Ni(II) concentration, adsorbent dosage, and temperature were investigated. The studies were also conducted to understand the effect of some co-existing ions which may be present in aqueous solutions. DHHC showed good adsorption potential for Ni(II) ions. The optimum initial pH value was selected as 5.0. The experimental data fitted well to the Langmuir adsorption isotherm model. Among the kinetic models tested for the adsorption of Ni(II), the pseudo-second-order model showed a good fit of the kinetic data. The thermodynamic parameters including the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes indicated that the adsorption of Ni(II) ions onto DHHC was feasible, spontaneous, and exothermic in the temperature range of 25-55°C. The results of this study showed the effectiveness and feasibility of DHHC for the removal of Ni(II) ions from aqueous solution.
- MakaleYalnız künye2012Adsorption of Phenol from Aqueous Solution on a Low-Cost Activated Carbon Produced from Tea Industry Waste: Equilibrium, Kinetic, and Thermodynamic Study
Gundogdu, Ali; Duran, Celal; Senturk, H. Basri; Soylak, Mustafa; Ozdes, Duygu; Serencam, Huseyin; Imamoglu, Mustafa
The ability of activated carbon which was produced by chemical activation using zinc chloride from tea industry wastes (TIWAC) to adsorb phenol molecules from aqueous solution was tested by equilibrium, kinetic, and thermodynamic parameters. Phenol adsorption on TIWAC took place with a high yield at pH values in the range 4 to 8. The optimum contact period was observed as 4.0 h and from the adsorption graphs plotted as a function of time; it was established that phenol adsorption on TIWAC conformed more to a pseudosecond-order kinetic model. Additionally, it was determined that the adsorption rate is controlled by intraparticle diffusion as well as film diffusion. It was established that phenol adsorption on TIWAC can be better defined by the Langmuir adsorption model and its adsorption capacity was 142.9 mg.g(-1) from the linear Langmuir equation. Temperature had an adverse effect on adsorption yield, and hence, the adsorption process was exothermic in our case. Moreover, increasing electrolyte concentration in the medium has a positive effect on adsorption yield. From the data obtained, it was concluded that the removal of phenol from aqueous solution by TIWAC produced from tea industry wastes with a very low cost took place with an extremely high performance.