The levels of selected essential (Ca, Fe, Zn, Mn, Cr and Cu) and potentially toxic (Cd and Pb) metals were analyzed using flame atomic absorption spectrophotometer (FAAS) from low grade coal and drinking water collected from Chilga, Ethiopia using composite sampling technique by developing an optimized digestion procedure and recovery tests. The average concentrations from the digests were found as Ca (3176.6 ± 12.3 μg/g), Fe (704 ± 3.2 μg/g), Zn (365 ± 5.8 μg/g), Mn (120.2 ± 0.6 μg/g), Cr (53 ± 0.33 μg/g), Cu(167 ± 0.1 μg/g), Pb (14.5 ± 0.12 μg/g) and Cd (0.8 ± 0.04 μg/g) in low grade coal and Ca (142.81 ± 0.05 μg/mL), Fe (9.632 ± 0.06 μg/mL), Zn (18.08 ± 0.4 μg/mL), Mn (3.21 ± 0.3 μg/mL), Cr (3.01 ± 0.02 μg/mL) and Cu(4.165 ± 0.004 μg/mL) in drinking water composite samples. While Pb and Cd were both not detected (ND) for the method used in drinking water sample located in Chilga near the coal area selected. Fe and Zn were obtained predominantly in coal and drinking water respectively.
Adsorption of acetic acid from aqueous solution onto activated carbon was investigated to evaluate the effects of initial acetic acid concentration, contact time, nature of adsorbent and adsorbent dose on the removal of acetic acid systematically. The optimal contact time value for acetic acid adsorption onto the activated carbon was found to be 30 minute. Greater percentage of acetic acid adsorbed with increase in the initial concentration of acetic acid and increase in amount of adsorbent used. Adsorption data was modeled using the Langmuir and Freundlich isotherms. For all the samples, these data fitted well the Langmuir isotherm models in the range of the concentrations tested. Maximum amount of acetic acid adsorbed was 16.67 m mol/g. Adsorption of acetic acid onto treated sugar cane bagasse was highly favorable sorption than the activated carbon and the peels of banana.
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