REMOVAL OF BORON WITH ULTRAFILTRATION (UF) - ELECTRODEIONIZATION (EDI) HYBRID SYSTEM
Project no. 21567 · Status: Kapanmış · 2020
Summary
The use of high purity water (ultrapure water) is required in the chemistry, pharmaceutical, energy sectors and especially in the semiconductor production stages. Weak electrolytes (SiO2, NH3, CO2, H3BO3) cannot be effectively removed from water by conventional separation methods because their ionization is low. In systems where ion exchange resins are used in ultrapure water production; when the resin capacity starts to reach saturation; Boric acid and silica, which have low ionization, are among the first ions observed in product water. In this study; the usability of hybrid methods created by using ultrafiltration (UF) and then electrodeionization (EDI) techniques in obtaining ultrapure water used in different industries was evaluated in terms of boron removal and the parameters affecting the boron removal performance of the methods were examined. In the first stage of the study, the polymer containing N-methylglucamine functional group was synthesized and used in the polymer complexing ultrafiltration system (PKUF), and the parameters (pH, polymer-boron ratio, time) affecting this system were investigated. The optimum polymer:boron ratio was determined as 60:1, contact time 1 hour and pH 6 optimum. Boron concentration was reduced from 5 mg/L to 1.6 mg/L with the PKUF method. The solution with this boron concentration was used as a feed solution in the EDI system and was used for boron removal; The effects of potential, feed solution flow rate, electrode chamber Na2SO4 conductivity, EDI system cell number and experiment times were investigated. The applied potential was determined as 30 V, the feed solution flow rate of 2 L/h and the conductivity of Na2SO4 500 µS/cm as optimum. When the experiment time is increased to 6 hours with the three-compartment EDI cell, the boron concentration is reduced to 0.006 mg/L, and when the number of cells in the EDI system is increased to five and the experiment time is 10 hours, the boron concentration is reduced to 0.00025 mg/L.