ADSORPTION OF NI (II) IONS FROM WASTEWATER ON ADSORBENTS DERIVED FROM NATURAL MATERIALS: KINETIC AND THERMODYNAMIC STUDYS.D. Patil, S.T. Morbale and N.T. Patel
The excessive exposure of nickel ions to the environment can lead to severe damage of kidneys, lungs, dermatitis and cancer. Therefore, it is necessary to remove nickel ions from wastewater. So batch mode adsorption experiments of Ni (II) ions on different natural materials were carried out in the present study. The parameters studied includes initial Ni (II) ion concentration, contact time, dose of adsorbents, pH and temperature. All Freundlich, Langmuir and Temkin adsorption isotherm models were found to be best fitted models as per the linear regression coefficient R2 values. The monolayer (maximum) adsorption capacities (qm) ranging from 4.608 to 13.514 mg/g for natural adsorbents under study. As qe(the) values are matched with qe(exp) showed that Lagergen pseudo -second order model fits the kinetics of adsorption of Ni (II) ions on these natural materials. Amount of Ni (II) ions adsorbed on adsorbents was found to be directly proportional with pH and temperature. According to thermodynamic analysis, adsorption of Ni (II) ions on adsorbents was favourable, spontaneous and endothermic physical adsorption. Out of the six adsorbents under study, Mango (Mangifera indica) leaf powder was found have greater adsorption capacity and Tamarind (Tamarindus indica) fruit shell powder had least adsorption capacity towards Ni (II) ions.