Anionic/Cationic Membranes Obtained by a Radiation Grafting Method for Use in Waste Water Treatment
✍ Scribed by Hegazy, El-Sayed A.; Abd El-Rehim, H. A.; Khalifa, Nevien A.; Atwa, S. M.; Shawky, H. A.
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 392 KB
- Volume
- 43
- Category
- Article
- ISSN
- 0959-8103
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✦ Synopsis
Investigations were carried out on di †erent ionic membranes, which were prepared by radiation-induced graft copolymerization. Cationic (low density polyethylene (LPDE)-g-poly(acrylic acid) (PAAc)) and cationic/anionic (LDPE-g-P(AAc/4-vinyl pyridine (4VP)) membranes) were used to elucidate the possibility of their practical use. The metal uptake via their functional groups was determined by using atomic absorption and X-ray Ñuorescence. The amount of metal uptake by the prepared membranes increased signiÐcantly as the pH of the metal feed solution increased (pH ¹ 5É3) and the chelated metal ions were easily desorbed by treating the membrane with 0É1 M HCl for 2 h at room temperature. The maximum uptake for a given metal was higher for the cationic/ anionic membranes than for the cationic ones. The selectivity of the cationic/anionic membranes towards di †erent metals was investigated using mixtures of two or three metals in the same feed solution. The membranes showed high selectivity towards Fe(III) ions. Characterization of the graft copolymers containing metals was determined by thermogravimetric analysis (TGA) and X-ray di †raction (XRD). TGA results showed that the decomposition of the graft copolymer in the presence of chelated metal ion occurred at temperatures above 300¡C. The XRD of LDPE-g-P(AAc/4VP) treated with Fe(III) at various concentrations showed that the crystallinity decreased to a certain limiting value. The complexed copolymers could be recycled several times and showed high selectivity to the Fe(III) ion in the presence of the other metal ions investigated. This may make such grafted membranes acceptable for practical use in waste water treatment.