Hardness removal from waters by using citric acid modified pine cone

In this study, an effective cation exchanger was developed from the pine cone by citric acid modification and its hardness removal properties from the waters were investigated. For this purpose, ground pine cone samples were subjected to a citric acid modification following NaOH saponification. Both of the raw (RPC) and modified pine cone (MPC) samples were subjected to standardized hardness removal tests by shaking with hard waters. These tests showed that citric acid modification significantly increases the cation exchange capacity of the pine cone. Most suitable size fraction of pine cone was determined as -16 + 30 mesh (600 mu m < x < 1200 mu m). Also, citric acid modified product obtained from this fraction was used in a continuous system to remove hardness from water. The results of this study showed that the MPC can be used for hardness removal from waters as a cheap, durable and environment -friendly material. Finally, regeneration experiments showed that the MPC can be used for hardness removal from water repeatedly by a simple HCl regeneration. (C) 2015 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.