Use of a newly synthesized Si-CPTS-AHAP adsorbent in the removal of Cr(vi) ions in wastewater treatment systems may potentially lead to low cost and highly efficient heavy metal removal.

Removal of chromium from wastewaters has been studied and the optimal process conditions were determined. The reverse osmosis (RO) technique, the sea water high rejection (SWHR) and high rejection brackish water (AG, SE, and SG) membranes were used. The chromium rejection depended on membrane type, pH of the feed water and operating pressure. The removal of chromium was most effective when the feed water pH 3. The rejection efficiency of the membranes increased in the order AG > SWHR > SG > SE. RO method can be efficiently used (with >91% rejection) for the removal of chromium from wastewater of chromium coating processes.

The 4-amino-2-hydroxyacetophenone was immobilized onto silica gel modified with\ud 3-aminopropyltrimethoxy silane. The carried reaction is classic condensation reaction. The\ud obtained structure was characterized by infrared spectroscopy and thermo gravimetric analysis.\ud The values of adsorption of Cu(II), Ni(II), and Co(II) ions were detected with an atomic\ud absorption spectrometer. The experiment conditions for effective sorption of the studied\ud metal ions were performed by using batch method. The maximum adsorption capacities\ud and isotherm parameters were calculated with using the Langmuir, Freundlich, and\ud Dubinin-Radushkevich isotherm equations. Thermodynamic parameters such as free energy\ud (ΔG°), entropy (ΔS°), and enthalpy (ΔH°) were also calculated from the experimental results.\ud The sorption results were used to explain the mechanism of the sorption. The modified\ud structure was successfully used in the separation of Cu(II), Ni(II), and Co(II) from the\ud aqueous solutions

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 (DG o ), entropy (DS o ), and enthalpy (DH o ) 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.