Examining the Performance of Improved Clay Soil Applied for Adsorption of Heavy Metals in a Polluted Underground Water

Abstract

In this research work, we carried out an examination to ascertain the performance of an improved clay soil applied to act as an adsorbent to aid the removal of heavy metals from underground water. In order to get this done, we decided to use well water from Elieta Community, a rural community in Ogba/Egbema/Ndoni Local Government Area of Rivers State Nigeria. This was inspired by the misuse of well water and other underground water sources thereby constituting an unfortunate pollution and poisoning of the underground water of the area which is their major source of water either for drinking, cooking, bathing, etc. without any form of purification or treatment. We also looked into the adsorption isotherms, kinetics and thermodynamics models as were used to evaluate the experimental results. Thus, from 0.5 to 2 g dosage, amount of metals removed increased from 69.81% to 83.43% for Cr6+, 54.51% to 78.24% for Cu2+ and from 82.15% to 91.16% for Zn2+. From pH 5.5 to 8.5, the amount removed increased from 71.68% to 84.18% for Cr6+, 64.79% to 80.48% for Cu2+ and from 78.56 to 92.09% for Zn2+ . The adsorption of Cr6+ and Cu2+ reached equilibrium at 60 minutes, while that of Zn2+ was at 90 minutes. All the adsorption isotherms showed good fit, but the Langmuir isotherm correlated better with the experiment. The maximum adsorption dimensions obtained from the Langmuir isotherm were 26.738, 28.902 and 22.831 mg/g for Cr6+, Cu2+ and Zn2+ , respectively. Considering the range of metals that were removed, the research shows that the clay soil is a good adsorbent for the removal of heavy metals in waters of Elieta Community.