ارزيابي قدرت جذب اگزروژل تترااتوكسي‌سيلان براي كاتيون‌هاي Cr3+ و Cu2+

Investigation of adsorption of Chromium & Copper ions on TEOS xerogel

در اين تحقيق توانايي اگزروژل تترااتوكسي سيلان(TEOS) براي جذب دو يون فلزي (+Cr3+،Cu2) ازمحلول هاي آبي مورد مطالعه قرار گرفت و تاثير عوامل مختلف مانند زمان، pH، مقدار جاذب و دما روي جذب اين فلزات بررسي گرديد. همچنين رفتار جذب اين دو كاتيون توسط مدل هاي مختلف ايزوترم مورد ارزيابي قرارگرفت. نتايج جذب بهترين تطابق را با مدل ايزوترم دوبينين- راداشكويچ داشتند كه مويد قدرت جذب بالاتر +Cr3 با بيشينه ظرفيت جذب 20/65 mg/g نسبت به+Cu2 با بيشينه ظرفيت جذب 10/42 mg/g بودند. مطالعات سينتيكي نيز نشان داد كه فرايند جذب در مورد+ Cr3 و+Cu2 از مدل شبه درجه دوم تبعيت مي كند. بررسي هاي ترموديناميكي نشان از خودبخودي بودن فرآيند جذب كاتيون هاي فوق دارد.

In this research, TEOS xerogel was produced by sol-gel method and the best adsorbents for removal of heavy metals were chosen by test on this xerogel. TEOS xerogel was used for adsorption of Cr(III) and Cu(II). Various parameters such as contact time, pH, amount of adsorbent and temperature effect on metals adsorption were investigated.Besides , different models of equilibrium adsorption isotherms like Freundlich , Tempkin and Dubinin-Radoshkevich isotherm model were studied and their constants were determined. By searching on final results got from these isotherms were showed that the Dubinin-Radoshkevich isotherm model was fitted well with adsorption data. From the kinetic studies were carried out, it became clear that Pesudo-second order model was fitted with adsorption data of Cr(III) and Cu (II) on TEOS . Thermodynamic investigations were showed that the adsorption process of all heavy metals on adsorbents is spontaneous.