جستجوی مقالات مرتبط با کلیدواژه « adsorption thermodynamic » در نشریات گروه « علوم پایه »

In order to study the equilibrium, kinetic and thermodynamic of cadmium (Cd) adsorption by grape and apple pruning residues biochars, batch experiments carried out with different initial concentration of Cd (0 to 200 mg/L) with 0.03 M NaNO3 as a background solution. The effect of pH (4, 5, 6), ionic strengths (0.01, 0.03, 0.1 M) and temperature (10, 20, 30, 40 0C) at different times (0 to 240 minutes) were investigated. The results showed that the removal efficiency and adsorption capacity of adsorbents decreased with increasing initial concentration. Among adsorption kinetic models, pseudo second order model was better fitted for experimental data (R2=1) and the equilibrium time is attained in 40 min for gape and apple pruning residue biochars. Ionic strength and pH of background solution significantly affected Cd adsorption and the highest adsorption capacity was obtained at pH 6, ionic strengths of 0.01M at 40 0C. Sorption capacity factors (qmax, KF, KT, qD) and sorption energy factors (n, KL, B) of gape pruning residue biochar was more than apple pruning residue biochar. The sorption energy parameter (E) of Dubinin-Radushkevich isotherm and Gibbs free energy change (ΔG) indicated that the Cd adsorption processes were physical and spontaneous. The separation factor of Langmuir (RL) indicated that the sorption reactions of Cd2 by grape and apple biochar is favorable (RL=0.15-0.50).