DOI: 10.5176/2301-3761_CCECP18.42
Authors: Dr. Esther Nthiga Dedan Kimathi, Prof. Jane Murungi, Prof. Ahmed Hassanali, Prof. Ruth Wanjau
Abstract:
Environmental pollution by heavy metals, such as lead Pb (II), copper Cu (II) and Cd (II) have become a growing problem due to their toxicity even at relatively low concentrations. Some diseases such as cancer, diabetes, and hypertension have been associated to toxicity of these metals. Industrial processes and agricultural activities are the sources of heavy metals in rivers and lake. Many methods have been developed to remove these metals from water but, they are not available in rural areas or are expensive for low-income groups. Most of the methods developed have focused only individual metal ions. Thus, there is need to address a combination of different metal ions and to see if the presence of some ions affects the adsorption efficiency of other metal ions. This study compared the efficacy of Pb (II) adsorption on acid modified avocado seeds (MAS), watermelon peels (MWP) and lemon peels (MLP) in the absence and presence of Cu (II) and Cd (II). Freundlich isotherm and Langmuir isotherm was used to describe experimental data for the adsorption of lead ion. Acid modified MWP demonstrated the highest uptake of Pb (II) (130.23 mg/g of the adsorbent), followed by MLP (87.24mg/g) and then MAS (70.45mg/g). Presence of Cd(II) or Cu(II) ions in the ratio of 1:1 reduced adsorption of Pb(II) ions to less than half on all the adsorbents, and presence of both metals in the ratio of 1:1:1, caused further reduction of the adsorption of Pb(II). Thus, the adsorption capacity of the adsorbents was highest in the mono-metal system and decreased with increase in the number of coions. These results show that, because of antagonistic effects of other metal ions, testing an adsorbent for a single element may not give the correct assessment of its effectiveness as an adsorbent.
Keywords: Modified fruit waste adsorbent, Pb(II), Cd(II) a Cu(II) interaction
Updating...