Boron pollution in the Simav River, Turkey and various methods of boron removal

Abstract

The present study was undertaken to investigate various methods for boron removal from the drainage waters of the Bigadic boron mines of Turkey. α-Cellulose, magnesium oxide and boron-specific resin Amberlite IRA-743 (Rohm & Haas Co.) were selected for the present work. Experimental results show that both the adsorption method using magnesium oxide and the ion-exchange operations are effective in removing boron from the drainage waters. Cellulose as an adsorbent has a minimum efficiency. MgO can be used effectively at a Mg/B mol ratio of 20 for three cleaning cycles with 85% removal efficiency but must be discharged and refreshed after the third cycle. Consumption of 18,100 tons of MgO per year in the removal system makes this process uneconomical. Boron-specific resin Amberlite IRA-743 in free-amine form is also uneconomical due to expensive regeneration steps. The capacity of this resin in salt-form was found to be 1.5 mg boron ml −1 resin at 10% boron leakage and at a flow rate of 161 h −1l −1. The possibility of reuse of 90% of the regenerant and production of 4400 tons of boric acid in the removal system with salt-form boron-specific resin, compensate the annual cost of chemicals and also bring in some profit.