Adsorption Equilibrium Studies on the Example of Nitrate Removal Onto Char Produced from Waste Tires

There have been investigated potential evaluation of equilibrium adsorption isotherm for the removal of nitrates from water solutions using two types of char produced in commercial-scale pyrolysis based on recycled waste rubber tires. Liquid phase adsorption studies were performed under batch conditions and maximum adsorption capacity was determined. Equilibrium data were mathematically modelled using two-parameters Langmuir, Freundlich, three-parameters Redlich-Peterson, Toth, Dubinin-Radushkevich, Radke-Praushnitz, combined Langmuir-Freundlich and four-parameters Fritz-Schlunder, Marczewski-Jaroniec, Bi-Langmuir adsorption models. Obtained results revealed the potential use of the studied char adsorbents for nitrates removal from aqueous media (the maximum adsorption capacity at equilibrium 10.07 mg/g, have been achieved for CH-1 char). The Langmuir-Freundlich isotherm had the best fit for the adsorption experimental data over the whole concentration range. The highest percentage of NO3 removal efficiency onto CH-2 char achieved in NO3 initial concentration range from 26.44 to 66.55mg/L reaching values in the range of from 80.74 to 78.7%.