ETCE (2014) 34-39 © STM Journals 2014. All Rights Reserved Page 34 Emerging Trends in Chemical Engineering ISSN: 2349-4786 (online) Volume 1, Issue 3 www.stmjournals.com Parametric Studies of In-house Resin for Hardness Removal Anuja Tripathi* Chemical Engineering Department, Indian School of Mines, Dhanbad, Jharkhand, India Abstract Presence of high amount of calcium and/or magnesium makes the water hard as these ions in water react with other chemical agents and constituents of metallic plumbing etc. The process accelerates in the presence of heat. It decreases the efficiency of the unit operation due to the formation of scales. Hence, scaling is the main issue for which hard water is required to be treated or polished. De-mineralized water finds wide application in the fields of steam generation plant, high-pressure boiler feed, power-production plant, process plant, cooling systems, steel mills, refineries, petrochemical complexes, hydrometallurgical, metals finishing etc. The high-purity water from a de-mineralized plant is typically used in computer chip, micro-electronics, semiconductor industries. A highly efficient resin Polyacrylamide 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. Keywords: hardness removal, poly (acrylamide carboxylic acid) or PAC, scaling, calcium, resin, effluent, parametric studies *Author for Correspondence E-mail: anujatripathi17@gmail.com INTRODUCTION Safe drinking water following prescribed limit of total dissolved solids as 500 mg/l as per IS and WHO is becoming scarce and hence we need to reuse and re-circulate the water. An amount of 1.0 g calcium/day is considered safe and though [1] calcium has less toxicity, persons who consume more than 4.0 g calcium/day run a risk of hyperparathyroidism-tumor in parathyroid gland, cancer, etc. Similarly low level of calcium may cause kidney stones etc. [2, 3]. Hence, an optimization of calcium content is required for potable water. Although calcium is crucial for bones formation in skeletal living beings, presence of the element in water is considered as hard, as it reacts with other chemical agents and deteriorate the properties of constituents of metallic plumbing etc. [4]. The process accelerates in presence of heat, therefore decrease efficiency of the unit operation due to the formation of scales [5]. Scaling can be overcome by using Ion Exchangers through the process of softening. Softening of water is the exchange of the hardness producing cations (preferably Ca ++ , Mg ++ etc.) with Na + or H + ion [6–8]. A schematic view has been depicted below. Fig. 1: Decationisation (All Cations Replaced by H + Ion).