Equilibrium adsorption of copper ions from copper (II) nitrate on humus : diploma thesis

Abstract

U ovom diplomskom radu ispitivana je ravnoteža adsorpcije bakrovih iona iz otopina bakrovih iona različitih početnih koncentracija na humusu u šaržnom reaktoru pri stalnoj temperaturi od 308 K, brzini miješanja od 200 okr min-1 te trajanju eksperimenta od 96 h. Porast početnih koncentracija otopine bakrovih iona ne utječe značajno na ravnotežnu koncentraciju adsorbiranih bakrovih iona na humusu jer se ona neznatno mijenja. Maksimalni kapacitet adsorpcije bakrovih iona na humusu postignut je pri koncentraciji od 8,016 mmol dm-3 te iznosi 0,518 mmol g-1 za zadane uvjete provedbe eksperimenta. Učinkovitost adsorpcije bakrovih iona na humusu opada s porastom početne koncentracije bakrovih iona te je maksimalan učinak adsorpcije bakrovih iona na humusu postignut pri najnižoj odabranoj početnoj koncentraciji od 4,049 mmol dm-3 i iznosi 60,320 %. Dobiveni eksperimentalni podatci testirani su Langmuirovom, Freundlichovom, Tothovom, Redlich-Petersonovom i Sipsovom izotermom. Procjenom kvalitete slaganja adsorpcijskih modela s eksperimentalnim podatcima, usporedbom izračunatih vrijednosti statističkih parametara za RMSE i χ2 te maksimuma kapaciteta adsorpcije i eksperimentalno dobivenog može se zaključiti da najbolje slaganje s eksperimentalnim podatcima pokazuje Tothova izoterma koja je razvijena kako bi proširila primjenu Langmuirovog modela u heterogenim sustavima.In this diploma thesis, the equilibrium adsorption of copper ions from the copper ions solutions of various initial concentrations was investigated in a batch reactor on the humus at a constant temperature of 308 K, a stirring speed of 200 rpm for 96 h. The increase in the initial concentrations of copper ions solutions does not significantly affect on the equilibrium amount of copper ions adsorbed on the humus because it slightly changes. The maximum adsorption capacity of copper ions on the humus was achieved at a concentration of 8.016 mmol dm-3 with the value of 0.518 mmol g-1 for the given experimental conditions. The adsorption efficiency of copper ions on the humus decreases with an increase in the initial concentration of copper ions, and the maximum adsorption capacity of copper ions on the humus was achieved at the lowest selected initial concentration of 4.049 mmol dm-3 with the value of 60.320 %. The experimental data obtained were tested on Langmuir, Freundlich, Toth, Redlich-Peterson and Sips isotherms. By estimating the quality of the agreement of adsorption models with the experimental data, comparing the calculated values of statistical parameters for RMSE and χ2 and the maximum adsorption capacity with the experimentally obtained, it can be concluded that the best agreement with experimental data is shown by the Toth isotherm, which was developed to extend the application of the Langmuir model in heterogeneous systems