Sorpční studie chromu na chemicky modifikované odpady z lískových ořechů

Abstract

Master thesis studies the adsorption kinetics and modeling of equilibrium adsorption isotherms in the process of adsorption of Cr(VI) from aqueous solution using a chemically modified hazelnut shells (Coryllus avellana L.). The thesis contains an introduction to the topic of adsorption, especially characteristics of the adsorption process, factors affecting the adsorption and description of Cr(VI). Also describes the methodology of grain modification and heat treatment of the adsorbent, including its chemical modification. Hydrochloric acid and sodium hydroxide of 1,0 mol∙l-1 concentration were used to activate the binding sites on the surface of the adsorbent. Cr(VI) was determined spectrophotometrically using 1,5-diphenylcarbazide. Two grain size fractions were studied, the most appropriate showed grain size of <0.5 mm for exposure time of 360 min, activated with hydrochloric acid for 30 min, with the resulting adsorption capacity q = 3.46 mg∙g-1 at the pH value 1,5. The equilibrium data was analysed using the Langmuir and Freundlich isotherms. Langmuir model appeared to be optimal to describe the equilibrium isotherms, resulting in regression value of reliability R2 = 0.9927. The experiment was performed at room temperature of 23 ± 2 ° C.