Sorption Studies of Chromate by Iron Oxide from Drinking Water

Chromium is well-thought-out heavy metal which is one of the enormously lethal due to its cancer-causing nature. In this study, iron oxide is used as adsorbent for chromate removal from aqueous solution as a function of pH, time, temperature, concentration of adsorbate and media dosage. The influence of pH on Cr (VI) sorption by iron oxide reveals that adsorption is significantly increased as pH is decreased from 8 to 2. The sorption rate is detected to be higher in the beginning and then it remains constant after 120 min of equilibrium time. The removal of Cr (VI) is found to be greater at higher temperature, which confirms the endothermic nature of Cr (VI) adsorption by iron oxide. Whereas, the kinetic investigations confirm that the chromate adsorption follows the pseudo second order with kinetic energy in the range of 8.4–83.7 kJ mol−1.

Adsorption of 2,4-Dichlorophenoxyacetic Acid from Aqueous Solution Using Carbonized Chest Nut as Low Cost Adsorbent: Kinetic and Thermodynamic

The activated carbon was made of carbonized chest nut shell (CCS) and used as low cost adsorbent for 2,4-D (2,4-dichlorophenoxyacetic acid) removal. The experiments were conducted at different temperatures such as 35, 45 and 55 °C and this system represents as L type adsorption behavior. The experimental data were modelled using several isotherm models such as Langmuir, Freundlich, Temkin and Dubinin Radushkevich. The adsorption dynamics were searched by applying pseudo first, pseudo second and intra particle diffusion models. The thermodynamic approach was conducted for determining the thermodynamic values of ΔH°, ΔS° and ΔG°.