An iminodiacetic acid group has been incorporated in Tamarind polysaccharide by a modified Porath's method of functionalization of polysaccharides in order to develop a hydrophilic flocculant cum cation exchanger. Because of greater selectivity and higher exchanger properties, chelating ion exchanger as well as weakly acid cation exchanger Tamarind iminodiacetic acid (TIDAA) find tremendous application in waste water treatment and the quantitative results have been given for removal of heavy metal from the reference solution and from Agucha open cast mine water, Bhi wara (Rajasthan), India.