Hardness Removal in Safe Drinking Water via In-house Resin

Abstract

Carboxylic acid has been developed in-house in Desalination Division, which is capable of removing
calcium to the extent of 98.5% in substantially short span of time of 5 min from feed containing
calcium as high as 500 ppm and the resin work excellently for streams having pH 4–7. Also, the
loaded metal ions can be recovered and resin can be reused. In this regard, experimental studies by
varying different process parameters viz., concentration, time, loading, mesh size, elution etc. have
been reported in this paper to highlight the basic parameters for resin selection.
The study indicates experimentation with basic parameters like variation of concentration, time, mesh
size, dose rate and elution for removal of calcium as a case study for hardness removal. The
parametric studies for sorption of calcium ion by dry sorbent investigated in batch operation which
exhibits substantial sorption (more than 99 %). within 15 min (99.4%)in contact with 18 to 20 ASTM
mesh size sorbenthaving resin loading of 1 g/100 mL effluent Elution with1NHCl solution is most
suitable (more than 98% elution) which helps in reuse of the sorbent.The above result indicates
possibility to use the resin for removal of hardness or polishing of such type of hardness producing
metal ions.

Keywords: hardness removal, poly (acrylamide carboxylic acid) or PAC, scaling, calcium, resin,
effluent, parametric studies