Fuat Güzel

Removal of copper, nickel, cobalt and manganese from aqueous solution by kaolinite

The removal of some heavy metals such as Mn(II), Co(II), Ni(II), and Cu(II) from aqueous solution is studied using a raw kaolinite. The sorption of these metals on kaolinite conformed to linear form of Langmuir adsorption equation. Langmuir C(m) constants for each metal were found as 0.446 mg/g (Mn), 0.919 mg/g (Co), 1.669 mg/g (Ni), 10787 mg/g (Cu) at 25 degrees C, respectively. Also, kinetic and thermodynamic parameters such as enthalpy (deltaH), free energy (deltaG) and entropy (deltaS) were calculated and these values show that adsorption of heavy metal on kaolinite was an endothermic process and the process of adsorption was favoured at high temperatures.

Effective removal of tetracycline from aqueous solution using activated carbon prepared from tomato (Lycopersicon esculentum Mill.) industrial processing waste

Activated carbon (TAC) prepared under optimized conditions with ZnCl2 activation from a new precursor; tomato industrial processing waste (TW), was applied as an adsorbent to remove tetracycline (TC) from aqueous solution. The factors (TAC dosage, initial TC concentration, contact time, ionic strength and solution temperature) affecting the adsorption process were examined at natural pH (5.7) of TAC-TC system in aqueous solution. Kinetic data was found to be best complied by the pseudo-second order model. The isotherm analysis indicated that the equilibrium data could be represented by the Langmuir model. The maximum adsorption capacity was identified as 500.0mgg(-1) at 308K.

APPLICATION OF SOME DOMESTIC WASTES AS NEW LOW-COST BIOSORBENTS FOR REMOVAL OF METHYLENE BLUE: KINETIC AND EQUILIBRIUM STUDIES

In this study, parsley stalks (PS), cucumber peels (CP), and watermelon seed hulls (WSH) were used as novel low-cost adsorbents to remove methylene blue (MB) from aqueous solutions. The biosorption of MB onto PS, CP, and WSH was investigated as a function of pH (2–10), initial dye concentration (25–450 mg/L), temperature (293–333 K), ionic strength (0.0–1.0 mol/L NaCl), and biosorbent dose (0.1–1.0 g/50 mL). While the biosorption of MB on PS followed the Freundlich isotherm, biosorption on CP and WSH followed the Langmuir isotherm at all the temperatures studied. The monolayer biosorption capacities of PS, CP, and WSH were found to be 400, 111.11, and 57.14 mg/g, respectively. The biosorption of MB onto PS followed pseudo-second-order kinetics, and the biosorption onto CP and WSH followed pseudo-first-order kinetics. Thermodynamic studies showed that the biosorption of MB onto PS, CP, and WSH was spontaneous and feasible. The pHzpc values of PS, CP, and WSH were found to be 6.26, 6.42, and 6.83, respectively. Desorption studies were also carried out with various desorbing agents. HCl and H3PO4 were more effective desorbents than other desorbents used.

The Characterization of the Micropore Structures of Some Activated Carbons of Plant Origin by N2 and CO2 Adsorptions

Abstract In this study, active carbons prepared from almond and hazelnut shells under various experimental conditions were investigated. Merck-2514 and Merck-2184 active carbons were used for comparison. N2 (77 K) gas and CO2 (273 and 195 K) gas adsorptions were determined as comparison criteria. Regarding the specific surface area and micropore volume results obtained from these adsorption data, it is concluded that N2 (77 K) adsorption by itself is inadequate in the characterization of active carbons which are low-sized microporous dominated. In addition, it is concluded that it would be useful to investigate CO2 (195 and 273 K) adsorption. The iodine and methylene blue tests at 298 K were also applied for the characterization of the carbon adsorbents mentioned. From these data it was seen that the iodine test can be applied as a total porosity indicator and that the methylene blue test can be used as a developed microporosity indicator. These results indicate that the best adsorbents were those prepare...

Bioremoval and recovery of Cu(II) and Pb(II) from aqueous solution by a novel biosorbent watermelon (Citrullus lanatus) seed hulls: Kinetic study, equilibrium isotherm, SEM and FTIR analysis

AbstractThe biosorption of Cu(II) and Pb(II) ions from aqueous solutions using a new sorbent, watermelon seed hulls (WSH), has been studied. The effect of pH (2–6), biosorbent dose (0.1–1.0 g), initial metal ion concentration (10–500 mg L−1), contact time (5–270 min), and temperature (293–333 K) was investigated. Equilibrium adsorption isotherms and kinetics were also investigated based on metals adsorption tests. The experimental data were analyzed by the Langmuir and Freundlich models of adsorption, and the results fitted well to the Langmuir isotherm. The kinetic data have been analyzed using pseudo-first-order, pseudo-second-order, and intraparticle diffusion equations. The experimental data fit very well with the pseudo-first-order kinetic model. The data obtained from adsorption isotherms at different temperatures were used to calculate some thermodynamic quantities, such as free energy (ΔGo), standard enthalpy (ΔHo), and standard entropy (ΔSo), were evaluated. The adsorption of these two metals on ...

Chemical modification of a cellulose-based material to improve its adsorption capacity for anionic dyes

ABSTRACT A cellulosic material was modified to enhance its anionic dye adsorption capacity. The chemically modified cucumber peel was characterized by FTIR, SEM, TGA, XRD, proximate and ultimate analyses, and pHzpc measurements, and was used for the removal of toxic textile dyes. The kinetic data followed the pseudo-first-order model. The isotherm data fitted to the Langmuir model giving maximum capacities of 95.24 and 129.87 mg g−1 for Reactive Black 5 and Direct Blue 71, respectively. Thermodynamic parameters suggest that the process is spontaneous and endothermic. The recovery of the adsorbed dyes was achieved by NH3 and NaOH solutions. GRAPHICAL ABSTRACT

The Effect of Surface Acidity upon the Adsorption Capacities of Activated Carbons

Abstract In this study the effects of the surface acidity of adsorbents on adsorption from solution are investigated. For this purpose, methylene blue (cationic) and metanil yellow (anionic) adsorbates, which have opposite ionic characters, are used. At 298 K, the values of surface acidity indicate that methylene blue molecules occur on the surface at a greater probability than those of metanil yellow. That is, metanil yellow molecules are repulsed from the surface and methylene blue molecules are attracted to the surface.

Evaluation of Pomegranate (Punica Granatum L.) Pulps for the Removal of Copper(II) Ions: Kinetic, Equilibrium, and Desorption Studies

Pomegranate pulp has been used as novel adsorbent for removing Cu(II) ions from aqueous solution. The optimum conditions for removal of Cu(II) ions were found to be pH 5.32, biosorbent dose 0.1 g, contact time 120 minutes, initial concentration 50 mg/L, and temperature 30°C. The kinetic data were well fitted to the pseudo-second-order model. The biosorption process agreed with the Langmuir isotherm model. Maximum monolayer biosorption capacity was 7.30 mg/g. Thermodynamic parameters suggest that the biosorption process is spontaneous and exothermic. Desorption studies were carried out with different desorbing agents.

Characterization of the Micropore Structure of Activated Carbons by Adsorptions of Nitrogen and Some Hydrocarbons

In the present study the effects of the duration of carbonization and physical activation properties of activated carbon from vegetable materials were investigated. Peanut shells were used to obtain active carbon. These shells were activated chemically with ZnCl2 and/or CO2 for different times, and the micropore structures of these active carbons were studied by measuring the adsorption isotherms for nitrogen and some hydrocarbons such as benzene, n-butane, isobutane, 2,2-dimethylbutane, and isooctane. As the physical activation time was increased, the primary micropores, which were measured at 0.01 relative pressure, were reduced, and they were replaced by larger secondary and tertiary micropores which were measured at 0.15–0.01 and 0.30–0.15 relative pressures. The ratios of the mesopore volume to the micropore volume also increased as the duration of physical activation increased.

Uptake of anionic and cationic dyes by highly effective porous carbon adsorber based on industrial processing residues

ABSTRACT In this work, we investigated the performance of porous carbon prepared from carob (Ceratonia siliqua L.) processing residues at optimized conditions for the removal of the Basic Green 4 (BG4) and Direct Red 28 (DR28) dyes from aqueous solutions. The influence of several parameters such as adsorbent dose, initial dye concentration, contact time and temperature was evaluated in batch adsorption experiments. Maximum adsorption capacities were observed as 769 mg g−1 and 323 mg g−1 for BG4 and DR28, respectively. These results suggest that BG4 and DR28 could be removed using a novel porous carbon from carob processing residues.