Nilgün Balkaya

Adsorption of Astrazon Blue FGRL onto sepiolite from aqueous solutions

Abstract In this study, adsorption of Astrazon Blue FGRL on sepiolite (meerschaum) from aqueous solution was investigated using different parameters like initial dye concentration, temperature, contact time and solution pH. The obtained results were then compared for all the parameters. At the end of batch adsorption studies, the equilibrium time, optimum pH and temperature were 90 min, 7 pH and 293 K, respectively. Adsorption isotherm of Astrazon Blue FGRL on sepiolite (meerschaum) was determined and correlated with common isotherm equations such as Langmuir and Freundlich models. The Freundlich model (r 2 > 0.98) appeared to fit the isotherm data better than the Langmuir model (r 2 0.99), through the first order kinetic model did not adequately fit the experiment values (r 2 < 0.99). SEM, XRD and FT-IR spectrum analyses were carried out. The obtained results showed that Sepiolite (meerschaum) can be an al...

Removal of heavy metals (Cu, Ni, Zn, Pb, Cd) from compost by molasses hydrolysate

AbstractThis study aimed to remove heavy metals (Cu, Ni, Zn, Pb, Cd) from composts using molasses hydrolysate, produced from molasses by-product of the sugar industry. Batch experiments were conducted to examine the effects of differing experimental conditions on the removal of heavy metals, according to contact time and solid–liquid ratio. Batch experiments achieved removal efficiencies of 66% for Cu(II), 52% for Ni(II), 57% for Zn(II), 51% for Pb (II), and 77% for Cd(II) at 60 minutes and 1:12.5 solid–liquid ratio. Column experiments achieved removal efficiencies of 91% for Cu, 86% for Ni, 99% for Zn, 61% for Pb, and 99% for Cd at 0.55 mL/minute flow rate and a solid–liquid ratio of 1:12.5 g/mL. Producing large quantities of highly acidic and heavy metal contaminated solution, compost with low pH, and decreasing some parameters’ concentrations of compost such as C, TKN, total P are the disadvantages of suggested technology.

A kinetic study on cadmium adsorption from aqueous solutions by pre-conditioned phosphogypsum

AbstractIn the present study, the effect of contact time, adsorbent dosage, and initial cadmium concentration on the adsorption of Cd(II) ions from aqueous solutions by pre-conditioned phosphogypsum was investigated. The kinetics of adsorption was studied and, pseudo-first-order, pseudo-second-order, and Elovich models were used to fit the experimental data, which was obtained from batch experiments. The kinetic adsorption data fitted well into the second-order kinetic model. Adsorption mechanism was explained with the intraparticle diffusion and Boyd kinetic models.

Ecological Risk Assessment of Heavy Metal Pollution in Urban Soils: A Case Study

In this study, geo-accumulation index (Igeo), enrichment factor (EF), potential ecological risk (Er), and risk index (RI) of five metals (Cu, Pb, Zn, Hg, and Cd) and Sc (as reference element for enrichment factor calculation) in soil samples were applied for assessing the pollution pattern and possible sources of heavy metals. Soil samples were collected from 27 different locations in Avcilar in the European part of Istanbul, Turkey. The mean Igeo values of Cu, Pb, Zn, Hg, and Cd were found between 0.12 and 0.96, which means that the soil contamination levels of these metals were uncontaminated to moderately contaminated. The EF mean values of Cu, Pb, Zn, Hg, and Cd were 1.70, 1.30, 1.30, 2.29, and 1.26, respectively. These EF results indicated that Cu, Pb, Zn, and Cd in the study area soil were affected by natural sources, whereas Hg was mainly caused by nature and partly influenced by human activities. The order of the mean values of Er in the soil samples was in the following descending order of Hg > Cd > Cu > Pb > Zn. Most of the soil samples showed low and moderate ecological risks.

Biosorption of Dye from Aqueous Solutions by a Waste Lignocellulosic Material

In the present study, the biosorption of Astrazon Blue FGRL (AB) which is one of the cationic dyes most commonly used in nylon and acrylic textiles from aqueous solution was studied onto tea waste (tea dust discharged after using), a waste lignocellulosic material. The effects of different parameters including biosorbent dosage, initial pH, contact time, initial dye concentration, and temperature were studied. Tea waste was characterized by Brunauer-Emmett-Teller (BET) surface area, FTIR, and SEM. The experimental equilibrium data were fitted to the Langmuir and Freundlich isotherms. The Freundlich isotherm model fitted to the experimental data better than the Langmuir isotherm. The maximum biosorption capacity, qmax, was found to be 263.16 mg/g. The experimental data were discussed in detail comparing with some other low-cost adsorbents reported for AB removal in the previous literature, considering qmax, adsorbent surface area, experimental conditions, isotherm models, and thermodynamics of the AB adsorption. The thermodynamic data indicated that AB biosorption was feasible but nonspontaneous, endothermic, and a chemisorption reaction.

Enteromorpha compressa macroalgae as biosorbent for heavy metal removal: a preliminary economical evaluation

AbstractIn this study, the feasibility of using Enteromorpha compressa macroalgae for developing a biosorbent for the use in metal removal from industrial wastewater was discussed in the light of economic models. The net present value and the internal rate of return were used to evaluate the economics of the process. It was concluded that supply to the market as a biosorbent of E. compressa creates an economic benefit to the producing institution.