Bilal Acemioğlu

Copper (II) adsorption from aqueous solution by herbaceous peat

In this research, the herbaceous peat collected from Gavurgolu peatlands, one of the biggest Turkish peatlands, was utilized as an adsorbent for the removal of copper (II) ions from aqueous solution. Adsorption experiments were conducted under various conditions, i.e., initial concentration, temperature, and pH. While the amount of Cu (II) adsorbed on the peat increased with increasing concentration of Cu (II) ions, it was not markedly affected by temperature and pH. Percentage removal was higher at lower concentration. For example, the maximum percentage removal of Cu (II) ions for initial concentration of 3 x 10(-4) M was 97.04% at 21 degrees C and pH 5.5. The adsorption capacity (Q(0)) of the peat was 4.84 mgg(-1) from Langmuir adsorption isotherm for the concentration range of 3 x 10(-4)-6 x 10(-4) M at 21 degrees C and pH 5.5. The equilibrium time of adsorption of Cu (II) ions was 150 min and independent of concentration and temperature. The amount of Cu (II) adsorbed at equilibrium time did not considerably change with temperature and pH. It was also determined that adsorption isotherm followed both Freundlich and Langmuir. Uptake mechanism of Cu (II) ions by the peat occurs via cation exchange (especially by means of Ca(2+) and Mg(2+)) as well as copper/peat complexation. Adsorption kinetic was consistent with the pseudo-second-order model.

Removal of methylene blue from aqueous solution using cotton stalk, cotton waste and cotton dust.

In this study, cotton stalk (CS), cotton waste (CW) and cotton dust (CD) was used as sorbents to remove methylene blue (MB) from aqueous solution by batch sorption technique. Effects of initial dye concentration, solution pH, solution temperature and sorbent dose on sorption were studied. It was seen that the removal of methylene blue increased with increasing initial dye concentration (from 25 to 100 mg/l), solution pH (from 5 to 10), solution temperature (from 20 to 50°C) and sorbent dose (from 0.25 to 1.50 g/50 ml). The maximum dye removal was reached at 90 min. Sorption isotherms were analyzed by Langmuir and Freundlich models at different temperatures of 20, 30, 40 and 50°C, and the results were discussed in detail. Moreover, the thermodynamics of sorption were also studied. It was found that the values of standard free energy (ΔG°) were positive for cotton stalk and negative for cotton waste and cotton dust. The values of standard enthalpy (ΔH°) and entropy (ΔS°) were found to be positive, and the obtained results were interpreted in detail. The results of this study showed that cotton stalk, cotton waste and cotton dust could be employed as effective and low-cost materials for the removal of dyes from aqueous solution.

Use of Aspergillus wentii for biosorption of methylene blue from aqueous solution

In this study, Aspergillus wentii was used as a biosorbent for the adsorption of methylene blue from aqueous solution. The effects of contact time, initial dye concentration, solution pH and temperature on biosorption were investigated. The contact time required (that is, the equilibrium time) for maximum dye biosorption was found to be 120 min. The amount of the dye biosorbed increased with increasing initial dye concentrations and solution pH, while it was decreasing with an increase in temperature. Percent biosorption was changed between 14.86 and 85.04 under all conditions studied. Desorption studies were performed by changing of the value pH among 3 - 10. Desorption was considerably affected by lower pH. The maximum percentage of desorption was found to be 29.51 at pH 3. Biosorption isotherm from equilibrium values followed Freundlich model.

A KINETIC STUDY OF SULFURIC ACID-CATALYZED LIQUEFACTION OF WOOD INTO PHENOL

The powders of monarch birch wood (Betula maximowiczina Regel) were liquefied into phenol using sulfuric acid as a catalyst at various temperatures and reaction times. Typical kinetic parameters of the degrading reaction of wood in the presence of phenol and the acid were determined using typical kinetic models. In addition, the activation parameters of the liquefaction of wood were determined according to transition-state theory. The results of showed percent liquefied wood that about 100% of the wood could be liquefied into phenol at a temperature of 150°C for about 2 h. However, about 68% of phenol was found to react mainly with wood components along with sulfuric acid and phenol itself. The kinetic studies showed that the liquefaction of wood into phenol using sulfuric acid obeyed a bimolecular type second-order reaction and Arrhenius law. The activation energy of the liquefaction was 68.5 kJ mol−1. Furthermore, the findings related with activation enthalpy showed that the liquefaction of wood possessed a primarily endothermic reaction nature.

Sorption of copper (II) ions by pine sawdust

The sawdust of Calabrian pine was used as sorbent for the removal of Cu(II) ions from aqueous solution of copper sulfate pentahydrate (CuSO4.5H2O) at different concentrations, pHs and temperatures. The results showed that about 65–81% of Cu(II) ions in the solution could be adsorbed on the sawdust. The percentage of adsorped Cu(II) ions onto the sawdust increased with increasing initial concentration. Kinetic studies indicated that the sorption process followed the first order reversible kinetic model. It was also determined that the sorption process obeyed the Freundlich isotherm. Furthermore, the sorption thermodynamic was investigated in detail.ZusammenfassungKiefernsägemehl wurde als Adsorbens benutzt, um CI(II)-Ionen aus wässriger Lösung von Kupfersulfat bei unterschiedlichen Konzentrationen, pH-Werten und Temperaturen zu entfernen. Etwa 65–81% der Kupferionen konnten aus der Lösung an Sägemehl adsorbiert werden. Der adsorbierte Anteil stieg mit erhöhter Anfangskonzentration. Kinetische Untersuchungen zeigten, dass die Sorption einer Reaktion erster Ordnung folgt und entsprechend der Freundlich-Isotherme verläuft. Auch die thermodynamischen Parameter der Reaktion wurden untersucht.

Removal of Methylene Blue from Aqueous Solution Using Cotton Stalk: As a Bioadsorbent

A batch adsorption system using cotton stalk as a bioadsorbent was investigated to remove methylene blue from aqueous solution. The system variables studied include adsorbent particle size, initial dye concentration and adsorbent dose. Based on the isotherm data obtained from the fittings of the adsorption kinetics, the Freundlich model (Regression coefficient R ≈ 0.99) appears to fit the adsorption better than the Langmuir model (Regression coefficient R ≈ 0.89). The Freundlich and Langmuir monolayer capacity had a mean values of 1.29 l/g and 1.054 mg/g, respectively.

COMPETITIVE REMOVAL OF MALACHITE GREEN AND RHODAMINE B USING CLINOPTILOLITE IN A TWO-DYE SYSTEM

Surface and groundwaters become contaminated with dyes due to discharge into the environment, which increases the risk of a number of human diseases. Many methods of dye removal from discharge waters at the source have been developed, but few are effective and the most effective method (activated carbon) is very expensive. The purpose of the present study was to test a natural zeolite (clinoptilolite type) as a potentially effective and inexpensive method to remediate dye discharge into the environment. In the removal experiments, malachite green (MG) and rhodamine B (RB) cationic dyes were used. The effects of various experimental conditions such as initial dye concentration, pH, and temperature on dye removal were investigated in a single-dye system. The degree of removal of MG and RB increased with increasing initial concentration and temperature of the dye in a single-dye system. An increase in pH decreased RB removal, but increased MG removal. In a two-dye system, MG and RB adsorption decreased by ~41.74 and 21.51%, respectively, due to competitive adsorption of the two dyes. Adsorption reflected a pseudo-second order kinetics model with high correlation coefficients (r2 = 0.996–1.000) in single-dye and two-dye systems. Adsorption was most consistent with the Langmuir-1 and the Redlich-Peterson isotherm models with high correlation coefficients (r2 = 0.987–0.999) in both systems. The Langmuir-1 adsorption capacities were determined as 43.86 and 44.25 mg/g for the removal of MG and RB in single-dye systems, respectively. In a two-dye system, the Langmuir-1 capacities were 20.62 and 31.54 mg/g for the removal of MG and RB, respectively.

Investigation of thermal behavior of phenol-wood condensation product

In this study, the thermogravimetric behavior and activation energy of birch wood (Betula maximoviczina Regel) wastes-phenol condensation product were studied at several different heating rates. The experimental findings were compared to data obtained for commercial phenolformaldehyde condensation products (novalak). From thermogravimetric curves, the percent weight loss of phenolated wood was found to be higher than that of novalak in percent weight loss. Moreover, the activation energies of phenol-wood condensation products were markedly higher than those of novalak for various heating rates. Also, the activation energies of the phenol-wood condensation product along with that of novalak were in the range of activation the energy values of plastics (50-250 kJ/mol K). Furthermore, the initial degradation temperature of the phenol-wood condensation product is about 15 °C lower than that of novalak.