Removal of arsenic from water using hardened paste of Portland cement.

Portland cement has been used as a new low-cost adsorbent for the removal of arsenic from the water environment. In the batch experiments conducted at an initial concentration of 0.2 mg l(-1) of arsenate, it was found that up to 95% of arsenate could be removed. Kinetic profiles were developed for various conditions. The effect of adsorbent dose, effects of common ions such as Ca2+, Mg2+, Fe3+/Fe2+, Cl-, SO4(2-), NO3(-), PO4(3-) and the effect of pH was studied. Adsorption isotherm studies were performed and it was observed that the Freundlich isotherm was followed with a better correlation than the Langmuir isotherm. Arsenite could also be removed up to approximately 88% using the same material. A new detection method for arsenate/arsenite was developed for routine analysis of arsenic and used during the entire study.