Sağlık Hizmetleri Meslek Yüksekokulu

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Biosorption Studies of Mushrooms for Two Typical Dyes
(Journal of the Turkish Chemical Society, Section A: Chemistry, 2020) Yıldırım, Ayfer; Acay, Hilal
This study investigated the adsorption behaviour of two cationic dyes, methylene blue (MB) and malachite green (MG) onto Pleurotus ostreatus, Armillaria tabescens, and Morchella conica mushrooms. The effects of contact time, initial dye concentration, and solution pH (3-11) were also determined. The adsorption on all mushrooms attained equilibrium within 120 min for both MB and MG. To evaluate the experimental kinetics data, the pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetics equations were utilised. The pseudo-first-order kinetic model demonstrated a good fit with all adsorption kinetics. The Langmuir and Freundlich isotherm models were used to analyse the mechanism of the adsorption isotherm. The adsorption equilibrium isotherm was in a good agreement with the Freundlich model. Thermodynamic parameters such as ΔH enthalpy variation, ΔS entropy variation, and ΔG free Gibbs energy variation were calculated at 303-323 K. The results suggested that the Pleurotus ostreatus mushroom was the most suitable adsorbent for both cationic dyes’ removal.
Kinetic and isotherm investigation into the removal of heavy metals using a fungal-extract-based bio-nanosorbent
(Environmental Technology and Innovation, 2020) Yıldırım, Ayfer; Acay, Hilal; Acay, Hilal
Adsorption is very economical and environmentally friendly method that is commonly accepted as a promising technique for the removal of heavy metals. In this study a fungal-extract-based (FE-CB) bio-nanosorbent was prepared and used as an efficient biosorbent for the removal of heavy metals, namely Cu(II) and Ni(II), from aqueous solutions. FE-CB was characterized by scanning electron microscope, Brunauer–Emmett–Teller surface area and porosity analyzer, Fourier transform infrared, x-ray diffraction, differential scanning calorimeter, thermalgravimetric analysis and zeta potential. The Brunauer–Emmett–Teller surface area, pore volume and average pore diameter of FE-CB were 7.43 m2/g, 0.060 cm3/g, and 2.82 nm, respectively. The adsorbtion properties of FE-CB onto both Cu(II) and Ni(II) were investigated in terms of biosorbent dosage, temperature, initial concentration of Cu(II) and Ni(II) ions, pH and contact time in the batch experiments. The dependence of the biosorption mechanism on pH was revealed and the optimum pH was determined as 6 for Ni(II) and 5 for Cu(II). The Langmuir and Freundlich isothermal models and the kinetic Pseudo-first-order and Pseudo-second-order kinetic models were used to describe the adsorption performance of FE-CB. The activation energy was calculated by pseudo-second-order rate constants. In addition, thermodynamic parameters, standard Gibbs free energy, standard enthalpy and standard entropy were analyzed using the (Van't Hoff equation). The biosorption process was found to be spontaneous, favorable and endothermic.
Synthesis and characterization of the molecularly imprinted composite as a novel adsorbent and its competition with non-imprinting composite for removal of dye
(Journal of the Turkish Chemical Society, Section A: Chemistry, 2021) Yıldırım, Ayfer; Acay, Hilal; Baran, Ayşe
ue to its high visibility, high resistance, and toxic effects, colored substances in the textile and other dyeing industries waste-water cause great damage to biological organisms and ecology. Therefore, current research efforts to develop high selectivity, specificity, and efficient water treatment technologies are very intense, and molecularly imprinting methods (MIM) constitute a category of functional materials to meet these criteria. Polymethylmethacrylate-chitosan molecularly imprinted composite (PMMAC-MIC) and non-imprinted composite (PMMAC-NIC) were successfully prepared by MIM. Dye adsorption performance of MIC and NIC composites was investigated by comparison. The obtained adsorbents were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and zeta potential techniques. The kinetics of adsorption followed a pseudo-first-order model while the Langmuir adsorption isotherm provided the best fit. The maximum adsorption capacity of dye was found as 93.78 mg/g for PMMAC-MIC and 17.70 mg/g for PMMAC-NIC at 298 K temperature, the initial dye concentration was 100 mg/L. Thermodynamic parameters indicated that the removal of dye from PMMAC-MIC was endothermic and spontaneous. Besides, the regeneration of composite was recycled four times.

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