A new method to remove and recover contaminating sodium salts from industrial wastewater utilising polymer-bound crown ethers

[摘要] English: The aim of this study was to develop a new technique to clean the totalfactory generated wastewater as seen in the light of the backgroundgiven in Chapter 1. It was decided to develop a material that would enable anindustry to complex sodium cautions from a contaminated source, and to releasethe complexed sodium cautions, under controlled conditions, at a previouslydetermined site, or receiving reservoir, in a cyclic manner.For this reason, 32 different functionalised crown ether derivatives weresynthesised to produce a series of 17 new crown ether derivatives, including 4carboxylic acid, 4 amide, 4 alcohol and 4 amine crown ether derivatives, withspacer ranging from one to four carbon atoms in the side chain that separate thefunctional group from the crown ether moiety. Selected crown ether functionalisedderivatives was anchored on polymeric supports and their sodium cautioncomplexation ability was determined.Twenty (20) polymeric carriers were also synthesised. These include thesynthesis of 12 new water-soluble polyaspartamide derivatives as well as 5 newpolyepichlorohydrin water-insoluble derivatives. The experimental procedures forthe synthesis of the water-soluble polymers could be tuned to achieve exact ratiosbetween polymer anchored crown ethers and several other polymer side chainscontaining functional groups. The carboxylic acid derivatives could be anchored tothe water-soluble polymer and this reaction could be tuned to achieve 100 %coupling, with the use of the coupling reagent O-benzotriazolyl-N,N,N',N'-tetramethyluronium hexafluorophosphate.An elastomeric solid support was also synthesised by the curing of hydroxyterminated polybutadiene with isophorone diisocyanate. It was also demonstratedthat crown ether derivatives and/or polymeric carriers could be anchored onto thiselastomeric solid support, with or without the use of a spacer between the elastomeric solid support and the crown ether. Several new elastomeric solidsupports containing crown ethers were synthesised.Complexation studies of Na+ dissolved in an aqueous phase by crown etherfunctionalised elastomeric solid supports were demonstrated, and it was found that1.28 g Na+ I m2 surface area of the sodium caution scavenging device could beremoved. Acid media was used to accomplish the release of the Na+ from thiselastomeric solid support, and it was found that 0.65 g Na+ I m2 surface area of thesodium caution scavenging device could be released.

[发布机构] University of the Free State