Boron and Iodine Removal from TFT-LCD Wastewater by Precipitation and by Reverse Osmosis
Date Issued
2012
Date
2012
Author(s)
Liu, Chao-Huan
Abstract
Manufacturing of TFT-LCD has become one of the most important industries in Taiwan in recent years. But due to polarizer process, the wastewater generally contains boron and iodine. The main objectives of this study were (1) to develop an effective method to remove boron and to find its optimal operating conditions, and (2) to investigate the feasibility of using reverse osmosis to remove and recover iodine in wastewater.
In this study, Ca(OH)2 was used as the mineralizer to precipitate B(OH)4－ to form Ca2B2O5•H2O. Due to the low concentration of boron (50 ppm), use of Ca(OH)2 alone was not effective, with the combined addition of Ca(OH)2 and H3PO4, the boron removal efficiency could be raised to 99% under pH=9 at 130℃ after 30mins.
Three reverse osmosis membranes produced from GE, Dow and Hydranautics were tested for removal and recover of iodine. The results showed that the membrane from Hydranautics (SWC5-LD-4040) was the most effective one. When influent concentration of iodine was 500 ppm, the removal efficiency could reach up to 95%; however, when influent concentration was less than 15 ppm, the removal efficiency was only 10%.
Subjects
TFT-LCD wastewater
boron
iodine
precipitation
reverses osmosis
Type
thesis
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