Adsorption of Cr(VI) from aqueous solutions using algerian pinus halepensis tannin foam

Abstract

In this study, new adsorbent tannin foam was prepared from Algerian natural pinus halepensis tannin (APTF). The prepared material has been used as an efficient and environmentally friendly adsorbent to remove chromium (Cr(VI)), which is considered as the most toxic pollutant in wastewater. The different features of the adsorbent in terms of the structural and morphological characteristics were studied. The impact of different factors on the adsorption process, such as pH, adsorbent mass, initial Cr(VI) concentration, and temperature, was investigated. The data obtained from the Cr(VI) adsorption revealed an improvement of the removal efficiency with increasing the adsorbent dose, the pH had a notable effect on Cr(VI) adsorption capacity, whereas the effectiveness decreased by rising the initial metal concentration. In addition, it was observed that adsorption efficiency enhanced with increasing temperature, indicating that the adsorption was endothermic and spontaneous in nature. Moreover, the results were best represented by the pseudo-second order kinetic model and the Langmuir isotherm model (qm = 400 mg·g-1) at 293 °K and pH ~2