Adsorption Efficiency of Cement Impregnated Magnesium Oxide on the Removal of Fluoride

Presence of fluoride in drinking water above the prescribed limit may lead to a severe health complication. We present in this paper the fluoride removal capacity of cement impregnated MgO (MgO-cement) from drinking water. MgO-cement was prepared by adding magnesium oxide (MgO) into the cement slurry solution in the ratio of 1:10. Batch experiments were performed as a function of adsorbent dose, contact time, effect of pH and effect of co-ions. The percentage removal decreases with increasing initial fluoride concentration. Co-ions effect revealed that hydroxide ion was found to interfere more with fluoride removal followed by bicarbonate and least effect with sulphate. Reaction mechanism follows Freundlich isotherms. From the kinetic study we observed that uptake of fluoride ion is fast in the first sixty minutes and equilibrium time found to be independent of the initial fluoride concentration. Adsorption kinetics followed the pseudo second order model showing that the sorption of fluoride is a complex process. Surface as well as intraparticle diffusion contribute in the sorption process. No leaching of magnesium in the treated water was detected

A Modified Non Electrical Filter for Decontamination of Iron Rich Water for Rural Application

A non-electrical filter is designed to cater the need of providing iron free water in forward and rural areas. The features of the unit are equipped with the aeration system and activated sand chemically coated by iron oxide as catalytic and filtering media which can bring down iron concentration from 12 mg/L to desirable limit. It increases the pH of water from acidic to pH above 7. This is in contrast to some indigenous water filter which existed in the North Eastern India that tend to remove iron below 4 mg/L. The modified filter is effective in reducing excess total dissolved solids (TDS) from drinking water. All other physical parameters found to be within the prescribed limit. It can give iron free water with output capacity of 25L/hr. The added advantage of the unit is the provision for back washing of the filter media and collection point of the precipitated iron at the lower bottom of the tank for safe discharge