Water softening behaviour of sand materials—Mimicking natural zeolites in some locations of Rameswaram Island, India

The present work is contributed for the softening of water using natural sand materials taken from Rameswaram Island, South India. After the study on the water quality parameters from well, tank, pond and spring sources, the sand materials from the respective sites were identified to be the able candidates as water softeners. The Si/Al ratio for the sand material from Sethumadhava tank was found to be closely resembling zeolites, majorly the clinoptilolite type. The surface area, pore volume and cation exchange capacity of Sethumadhava sand was greater than the from Uchipuli sand. From the column studies, the parameters viz., qtot, column performance and qeq were calculated as a function of particle size, source, regenerant, initial Ca2+ concentration and bed depth. The water softening efficiency was increased according to the increase in sodium chloride concentration, initial Ca2+ concentration and bed depth. The dissolution of Al and Si during the softening process has also been discussed. The sand materials have been characterized with FTIR, SEM, XRD, solid state MAS NMR and solid state DRS techniques before and after the softening process.