Grape bagasse as a potential biosorbent of metals in effluent treatments

Grape bagasse generated in the wine production process was characterized through X-ray diffractometry, Fourier transform infrared spectroscopy, scanning electron microscopy, nuclear magnetic resonance and thermogravimetric analysis. The efficiency of this natural material for Cd(II) and Pb(II) adsorption was evaluated using a batch adsorption technique. Factors affecting metal adsorption such as pH and contact time were investigated. Maximum adsorption was found to occur at pH 7.0 and 3.0 for Cd(II) and Pb(II), respectively, and a contact time of 5 min was required to reach equilibrium for both metals. With these conditions, adsorption studies were performed using a single solution. In addition, to calculate the adsorption capacities for each metal, the Langmüir isotherm model was used. The adsorption capacities were found to be 0.479 and 0.204 mmol g−1 for Cd(II) and Pb(II), respectively. The results showed that grape bagasse could be employed as a low-cost alternative adsorbent for effluent treatment.