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    Adsorptive removal of Co(II), Ni(II), and Cu(II) ions from aqueous media using chemically modified sporopollenin of Lycopodium clavatum as novel biosorbent
    (DESALINATION PUBL, 2014) Cimen, Aysel; Bilgic, Ali; Kursunlu, Ahmed Nuri; Gubbuk, Ilkay Hilal; Ucan, Halil Ismet
    In this study, sporopollenin of Lycopodium clavatum spores was used for sorption experiments. (E)-4-((2-hydroxyphenylimino) methyl) benzoic acid (HPBA) immobilized sporopollenin (Sp) was employed as a sorbent in sorption of selected heavy metal ions in aqueous solutions. The sorbent material was prepared with sequential treatment of sporopollenin with silanazing compound and HPBA. Experimental conditions for effective sorption of heavy metal ions were optimized with respect to different experimental parameters using the batch method in detail. pHs for maximum sorption of Cu(II) Ni(II) and Co(II) ions were found in six and five, respectively. Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm equations were applied to the experimental data. Thermodynamic parameters such as free energy (Delta G degrees), entropy (Delta S degrees), and enthalpy (Delta H degrees) were also calculated from the sorption results and were used to explain the mechanism of the sorption. The results indicated that this sorbent is successfully employed in the separation of trace Cu(II), Ni(II), and Co(II) from the aqueous solutions.
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    Removal of chromium ions from waste waters using reverse osmosis AG and SWHR membranes
    (MAIK NAUKA/INTERPERIODICA/SPRINGER, 2014) Cimen, Aysel; Kilicel, Fevzi; Arslan, Gulsin
    The aim of this work is to investigate removal of chromium from waste waters. The effect of pH and concentration of the feed water and operating pressure on the chromium rejection were also investigated. In the study; the reverse osmosis (RO) technique and the sea water high rejection (SWHR) and high rejection brackish water (AG) membrane were used for the separation process. Results of the study indicated that chromium rejection mostly depends on the membrane type, pH of the feed water and operating pressure. Also pH of the feed water was found to be 3 for the effective removal of chromium. Furthermore the rejection efficiency of the membranes was found to be in the order of AG > SWHR. For two membranes, chromium rejection increased with increasing operating pressure. Finally, waste water sample containing 7542 mg/L (with 100 mg/L) of chromium was treated by using RO technique with AG membrane. RO could be efficiently used (with > 91% rejection) for the removal of chromium from waste water sample.