Orange tree leaves, a perfect adsorbent for the removal of Cd (II), Co (II), Zn (II) from wastewater

The present study explores the uptake capacity of low-cost agricultural waste for the removal of heavy metals, Co2+, Cd2+ and Zn2+, from aqueous solution. Studies conformed to Freundlich, Langmuir and Temkin adsorption isotherms. The values of constants for the thermodynamic and kinetic isotherms were found. The kinetic isotherm experiment data could be well described with the pseudo-second order kinetic model and thermodynamic studies indicated that the adsorption processes were spontaneous and endothermic with orange tree leaves under natural conditions. Experiments showed that Cd2+, Co2+ and Zn2+ adsorption increased with increasing pH and decreased with increasing the temperature and concentration of solutions. This study indicates that the developed method based on orange tree leaves is very simple, low-cost, fast and trusty for the removal of heavy metal ions from water and wastewater samples.