Utilization of chemically modified apple juice industrial waste for removal of Ni2+ ions from aqueous solution

Present study was carried out to evaluate feasibility of apple pomace (AP) and its chemical modification with succinic anhydride for removal of Ni2+ ions from water. Maximum adsorption capacity (qmax) of AP and chemically modified apple pomace (CMAP) were found to be 83.33 and 256.41 mg g−1, respectively, using Langmuir adsorption isotherm. Negative zeta potential was increased about 44 % on the surface of AP after chemical modification. The amount of adsorbent dose and time were decreased from 0.8 to 0.4 g and 120 to 30 min, respectively. Plausible mechanism supported by FTIR data showed that –OH, –COO, –CO, –C–O–C, –CONH2 and –NH2 groups were involved in adsorption of Ni2+ ions by coordinate bonding with lone pair of negatively charged oxygen and nitrogen groups for AP and CMAP. Negative value of ∆H° indicated exothermic nature of reaction and adsorption decreased as temperature increases from 303 to 333 K. Desorption and regeneration study revealed that CMAP was reused in three cycles, which make biosorbent more economical. By surface modification of AP, adsorption capacity was increased about 3.0-fold than unmodified one.