Iron and Manganese Removal from Groundwater Using High Quality Limestone

Abstract

Several techniques are used for iron and manganese removal from groundwater. Among these treatments, adsorption has been proven to be a very effective in metal removal for groundwater treatment. Thus, limestone has been proposed as adsorption media because of its low cost. In this study, the mineral contents of limestone were detected using X-ray fluorescence (XRF). XRF results showed that limestone contains 97.93% CaCO3, 0.87% MgO, and 1.2% other elements. Groundwater sample was obtained from USM borehole located at 5° 08’ 50.5”N and 100° 29’ 34.7”E. A batch study was carried out for various dosages of limestone media (5–50 g) in 200 mL of groundwater sample. The highest iron and manganese removal was more than 90% and 70%, respectively, at optimum dosage of 40 g/200 mL sample. Adsorption data were modeled using Langmuir and Freundlich adsorption isotherms. The batch study result shows that monolayer Langmuir isotherm fitted the experimental data better than the Freundlich isotherm. The correlation coefficient (R2) in the Langmuir isotherm for both metals were 0.84 and 0.97, whereas 0.83 and 0.23 in the Freundlich isotherm, respectively. Based on the present results, application of limestone as adsorbent media can be a good alternative of groundwater treatment because of the low cost of the media. Thus, the use of limestone could help to overcome the excessive iron and manganese problem in water treatment plants.