Hardness removal from waters by using citric acid modified pine cone

• An ion exchange material was prepared by citric acid modification from pine cone.
• The influences of citric acid modification and particle size on the hardness removal efficiency from water were investigated in batch system.
• Some characterization tests of raw (RPC) and modified pine cone (MPC) samples, which are important in terms of using in a column system, were made comparatively.
• The results of the study showed that the citric acid modified pine cone is an effective and durable material to remove the hardness from waters.

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 µm < x < 1200 µm). 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.

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