Emine Malkoc

Thermodynamic and kinetic studies for environmentaly friendly Ni(II) biosorption using waste pomace of olive oil factory

The objective of this study is to assess the environmentaly friendly Ni(II) adsorption from synthetic wastewater using waste pomace of olive oil factory (WPOOF). Batch kinetic studies were performed in order to investigate the adsorbent and adsorbate dose, solution pH, agitating speed and temperature. The maximum Ni(II) adsorption was obtained at pH 4.0. The equilibrium nature of Ni(II) adsorption at different temperature was described by the Freundlich, Langmuir and Temkin isotherms. The equilibrium data fit well the Temkin and Langmuir isotherm. The monolayer adsorption capacities of WPOOF as obtained from Langmuir isotherm at 60 degrees C was found to be 14.80 mg/g. The adsorption mechanism was examined by the FTIR technique. The results of the thermodynamic investigations indicated that the adsorption reactions were spontaneous (DeltaG < 0), slightly endothermic (DeltaH > 0) and irreversible (DeltaS > 0). The pseudo first-order, pseudo second-order, Elovich and intraparticle diffusion kinetic models were used to describe the kinetic data.

The removal of Cu(II) from aqueous solutions by Ulothrix zonata.

In this work, adsorption of copper(II) ions on alga has been studied by using batch adsorption techniques. The equilibrium biosorption level was determined as a function of contact time at several initial metal ion concentrations. The effect of adsorbent concentration on the amount adsorbed was also investigated. The experimental adsorption data were fitted to the Langmuir adsorption model. The free energy change (deltaG0) for the adsorption process was found to be -12.60 kJ/mol. The results indicated that the biomass of Ulothrix zonata is a suitable biosorbent for both the removal and recovery of heavy metals from wastewater.

Investigation of pH effect by Fenton-like oxidation with ZVI in treatment of the landfill leachate

Abstract In this study, effect of pH by Fenton-like with zero-valent iron (ZVI) process, advanced oxidation process in the leachate treatment, was investigated. The effect of pH value on colour and COD removal from leachate was determined at five initial pH values, 2.0, 2.5, 3.0, 3.5 and 4.0 (ZVI = 0.05 g/L, H2O2 = 150 mg/L). The highest colour and COD yield were obtained at pH 2.0. The colour removal was 87.9% (in 620 nm wavelength) and the COD removal was 74%. Experimental data from COD degradation with the Fenton-like process were analysed by using the zero-, first-, second-order and BMG kinetic models.

Adsorption of phenol by MMT-CTAB and WPT-CTAB: Equilibrium, kinetic, and thermodynamic study

ABSTRACT In this study, the phenol adsorption capacity of cetyltrimethylammonium bromide modified clays (MMT-CTAB) and cetyltrimethylammonium bromide modified pulp tea (WPT-CTAB) were studied. In batch adsorption experiments performed with MMT-CTAB, the effects of parameters such contact time, phenol concentration, pH of solution and adsorbent dosage were investigated. The effect of temperature on phenol adsorption onto MMT-CTAB and WPT-CTAB was examined; equilibrium and thermodynamic studies were completed. The highest phenol removal was found at pH 4.0 for MMT-CTAB and WPT-CTAB. To analyze the kinetics of phenol adsorption onto MMT-CTAB, the pseudo first-order and pseudo second-order kinetic models were applied. The kinetic data fitted better to the pseudo second-order model than the pseudo first-order kinetic model for MMT-CTAB. The characterization of adsorbents in phenol adsorption was clarified with the FTIR technique. Thermodynamic parameters such as ΔH°, ΔS° and ΔG° were calculated for each adsorption process. The adsorption process was found to be exothermic and spontaneous for phenol adsorption by MMT-CTAB and WPT-CTAB. The results were analyzed with the Langmuir, Freundlich, Temkin and Harkins–Jura equations using linearized correlation coefficients at different temperatures. The Langmuir equation was found to best represent the equilibrium data for phenol adsorption onto MMT-CTAB and WPT-CTAB.

The degradation of landfill leachate in the presence of different catalysts by sonolytic and sonocatalytic processes

ABSTRACT In the study, the degradation of landfill leachate by single ultrasound (sonolytic) and sonolytic combined with Fe2+ and TiO2 catalysts was carried out in laboratory conditions. The effect of pH and ultrasonic wave amplitude was also investigated in terms of color removal, total organic carbon (TOC) and chemical oxygen demand (COD) from leachate by the sonolytic degradation process. In this process, the color removal efficiency was recorded as 81.81% at 620 nm, pH = 2.0 and 70% wave amplitude. The sonocatalytic degradation of landfill leachate accompanied by different catalysts was studied by using the 70% wave amplitude at pH = 2.0 and room temperature for 20 min. The sonocatalytic degradation of leachate by using Fe2+ and TiO2 was found to be significantly higher than sonolytic degradation (p < 0.05). As the Fe2+ concentration increased from 1.0 to 3.0 mg/L, the COD and color removal of leachate significantly decreased (p < 0.05) from 50 to 35.7% and from 95.5 to 90.9%, respectively. The experimental data obtained from sonocatalytic degradation was analyzed using the Behnajady–Modirshahla–Ghanbery (BMG) kinetic models and found to be compatible. The results showed that the combination of catalyst and sonolysis was a highly effective way to remove color, COD and TOC from landfill leachate.

Sızıntı Suyundan Fenton-Benzeri Prosesi İle Kimyasal Oksijen İhtiyacı ve Renk Giderimine ZVI ve H2O2 Konsantrasyonlarının Etkisi

Sizinti sulari, kompleks yapilari ve yuksek kirletici konsantrasyonlarindan dolayi aritimi zor atik sulardir. Bu calismada; sizinti sularindan Fenton-benzeri oksidasyon ile renk ve kimyasal oksijen ihtiyaci (KOI) giderimi calisilmistir. Renk ve KOI giderimine sifir degerlikli demir (ZVI) ve H 2 O 2 konsantrasyonunun etkisi incelenmistir. Renk giderimi 436, 525 ve 620 nm olmak uzere farkli uc dalga boyunda degerlendirilmistir. En yuksek KOI (%74.4) ve renk giderimi (436 nm’de %71, 525 nm’de %80.3 ve 620 nm’de %87.9) 0.05 g/L ZVI konsantasyonunda belirlenmistir. 200 mg/L H 2 O 2 konsantrasyonuna kadar artan H 2 O 2 konsantrasyonu ile renk ve KOI gideriminin de arttigi gozlenmistir. Optimum degerler; 20 dakikalik bir reaksiyon suresinde ve pH=2.0’de ZVI=0.05 g/L, H 2 O 2 =150 mg/L olarak bulunmustur. Ulasilan optimum sartlarda toplam organik karbon (TOK) giderimi %50 civarinda belirlenmistir.

The removal of COD and color by Fenton oxidation from leachate of Erzurum municipal solid waste landfill

The optimal conditions for treatment of leachate were determined as pH = 2.5, Fe2+= 2 mg/L and H2O2= 100 mg/L. Under the optimal conditions, approximately 90% color (at 620 nm), 84% color (at 525 nm), 74% color (at 436 nm) and 47.8% COD removal efficiency from leachate were achieved after 20 min of reaction. Depending on the results obtained experiments, Fenton process has been used successfully in removal of COD and color in landfill leachate.