Abstract

Preparation of poly (DMAEM)-cross linked pregelled starch graft copolymer and its application in waste water treatments

Author(s): Kh.M.Mostafa1, Abdul Rahim Samarkandy, A.A.El-Sanabary

Pregelled starch (PS) was first cross linked with epichlorohydrin (ECH) to obtain insoluble cross-linked pregelled starch (CPS). The latterwas graft copolymerized with different amounts of dimethylaminoethyl methacrylate (DMAEM) using potassium permanganate / sulphuric acid redox system. This was done to obtain six levels of poly (DMAEM)-cross linked pregelled starch graft copolymers (PDMAEMCPS) having different graft yields (expressed as N %) with increasing order and designated as (PDMAEMCPS 1 to PDMAEMCPS 6). The latter copolymerswere dispersed in aqueous solution of heavymetal ions Cu (II) ions and filtered to formpolymer –metal ions complex. Different factors affecting the heavy metal ions removal such as pH, extent of grafting, treatment time and starch dose were studied in detail. It was found from the obtained results that; the residual metal ions removal from their aqueous solutions increased with (a) increasing the extent of grafting ofPDMAEMCPS i.e. fromPDMAEMCPS 1 to PDMAEMCPS 6; (b) increasing the pHof themetal ions solution complex from1 to 8; (c) increasing the starch dosage from0.25 to 2.0 %(W/V), then leveled off thereafter, (d) increasing the time of the reaction up to 20 minute then leveled off after that. On the other hand, Pb, Cd and Hg ions were also removed from their solutions with different extent. Furthermore, the prepared copolymer could be recovered bywashing themetal ions fromthe complexwithweak acid 1 N HNO3 (pH 2) and the metal-binding activity of the starch was slightly reduced by this process. Finally, the ability of PDMAEMCPS to remove three types of acid dyes from their solutions was also reported.