Mehmet Mahramanlıoğlu

Adsorption of fluoride from aqueous solution by acid treated spent bleaching earth

Acid treated spent bleaching earth was studied to assess its capacity for the adsorption of fluoride from aqueous solutions. Adsorption isotherms have been modeled by Langmuir and Freundlich equations and isotherm constants for both isotherms were calculated. The effect of the adsorbent concentration on the adsorption was studied. The dependence of the adsorption of fluoride on the pH of the solution has been studied to achieve the optimum pH-value and a better understanding of the adsorption mechanism. It has been found that maximum adsorption of fluoride from aqueous solutions takes place at pH-value of 3.5. Second-order equation was used to describe the adsorption rate of fluoride and adsorption rate constant was calculated. Intraparticle and mass transfer coefficients were calculated. The influence of addition of the anions on the adsorption of fluoride was also studied to simulate industrial waste waters and the addition of anions decreased the adsorption of fluoride on the acid treated spent bleaching earth (SBE).

Removal of 2,4-D from aqueous solution by the adsorbents from spent bleaching earth.

Abstract The removal of 2, 4‐D (2, 4‐ dichlorophenoxyacetic acid) from aqueous solutions by activated spent bleaching earths (SBE) was studied at 20 °C. Experiments were performed as a function of time, initial concentration, dose and particle size of the adsorbent. The Langmuir and Freundlich adsorption equations were fitted by the adsorption data obtained. The values of Langmuir and Freundlich constants were determined. The adsorption kinetic was found to follow Lagergren equation. Both the boundary layer and intraparticle diffusion played important roles in the adsorption rate of 2, 4‐D. As the size of the adsorbent increased, the time to reach equilibrium increased but adsorption capacity decreased.

Removal of Phenolic Substances from Water by Adsorption and Adsorption-Ultrafiltration

In this work a magnetic adsorbent, magnetic activated carbon (MAC) was prepared and characterized by powdered X-Ray diffraction (XRD). A comparison was made between powdered activated carbon (PAC) and MAC for foul control in ultrafiltration (UF) membrane processes. First, the adsorptive parameters for PAC and MAC were determined for phenol, chlorophenol, nitrophenol, and hydroquinone. Equilibrium data fitted well to the Langmuir model in the studied concentration range of the adsorbates. Adsorption kinetics followed a pseudo second-order kinetic model rather than pseudo first-order kinetic model. These adsorbents were then used in combination with UF membrane. The parameters like percent rejection and flow rate for the hybrid UF/PAC and UF/MAC were determined. The influences of both adsorbents on flow rates and percent rejections were almost equal. The problems associated with PAC in the UF processes like cake formation and blackening of the pipes were not observed for MAC. MAC was removed from the slurry after use through a magnetic process.

Removal of MCPA from Aqueous Solutions by Acid‐Activated Spent Bleaching Earth

The removal of MCPA (4‐chloro‐2‐methyl phenoxyacetic acid) from aqueous solutions by activated spent bleaching earth (SBE) was studied as a function of time, initial concentration, adsorbent concentration, and temperature. The Langmuir and Freundlich isotherms were fitted by the adsorption data obtained. The values of Langmuir and Freundlich constants were determined. The adsorption kinetics was described by the Lagergren equation. Mass transfer coefficient and thermodynamic parameters were also calculated. Column experiments were conducted and brekthrough capacities were found for different concentrations and different flow rates. The study demonstrates that acid‐treated SBE could be used as an efficient adsorbent for the removal of MCPA–bearing wastewater effluents.

Removal of MCPA (4-Chloro-2-Methylphenoxy-Acetic Acid) from Aqueous Solutions Using Adsorbent Produced from Elutrilithe

Elutrilithe is a mixed alumina-silicate/carbon material and a solid waste of coal mines. In this study we tried to produce a new adsorbent from elutrilithe. The elutrilithe was treated with zinc chloride in an N2 medium. The adsorption capacity of the new adsorbent was measured with MCPA (4-chloro-2-methylphenoxy-acetic acid), which is a pesticide. The adsorption experiments were carried out as a function of time, initial concentration, agitation rates, and temperature. The Langmuir model was used to fit the equilibrium data. Satisfactorily fitting the data and consistency in parameter values indicated this isotherm could be used for the system. The adsorption kinetic results were interpreted by second-order rate equation, and rate constants were calculated for different agitation rates. The intraparticle rate diffusion constants were calculated for different agitation rates. Thermodynamic parameters were calculated. The negative values of enthalpy change indicated the exothermic nature of the adsorption process, and the negative values of ΔG0 were indicative of the spontaneity of the adsorption process.