Boron is an element distributed widely in environment mainly in the form of boric acid or borate salts. Boron is an element of demand because of its use in many high technology materials. Moreover boron is an essential element for growth of plants, but may also result in toxicity when present in excessive amounts. As the range between a deficient and toxic amount of boron is very narrow, imbalances in boron nutrition are well-known. For the removal of boron from aqueous solutions, various methods exist which are chemical coagulation, adsorption, solvent extraction and ion
exchange processes. In this study, an alternative, energy efficient and easily scalable membrane based method, polymer enhanced ultrafiltration (PEUF) was developed for removal of boron from aqueous boron solutions. PEUF process consists of two steps: complexing boron with a water soluble polymer then removing the complex by ultrafiltration. Previously, boron removal from aqueous solutions was studied in a continuous process with a commercial ligand, polyvinyl alcohol (PVA). In our study, three newly developed polymers, which are derivatives of N-methyl-D-glucamine (P1) and iminodipropylene glycol(P2 and P2G) were used as the boron complexing ligand. P1 and P2 are linear polymers, while P2G is cross linked version of P2. The pilot scale system utilized for the PEUF process accommodates a spiral wound cellulose cartridge with 10000 Da molecular weight cutoffs (MWCO). The effects of operating parameters on performance of PEUF were investigated. The experimental parameters studied are metal/polymer ratio (loading) (0.01-1), pH (7-10). Boron analyses of the samples were made by using ICP-AES. Maximum removal (retention) was 90.1 %. The permeate flux remained constant at around 20 L/m2.hr and was not affected by the operating parameters. Decrease in loading caused the retention of boron to increase. Also at high pH values, retentions were relatively higher. Results showed that PEUF could be a successful alternative method for removal of boron.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/4/1135193/index.pdf |
| Date | 01 January 2003 |
| Creators | Yurum, Alp |
| Contributors | Yilmaz, Levent |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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