Affiliations: State Key Laboratory of Environmental Aquatic
Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of
Sciences, Beijing 100085, China
Abstract: In order to improve the flocculation efficiency of
polydiallyldimethylammonium chloride (PDADMAC), high molecular weight PDADMAC
should be prepared from high purity diallyldimethylammonium chloride (DADMAC)
monomers. In this paper, a cleaner method with microwave irradiation and alkali
solidification was proposed for preparing high pure DADMAC by selective heating
under low temperature, and the prepared high purity DADMAC is characterized
using FTIR and atomic absorption spectrometry. The new method provides a
solution to the key technical problem of PDADMAC synthesis. Comparing with the
conventional methods, the results showed that the advantages of the novel
synthesis include: (a) high purity DADMAC is improved from 57% to 71%; (b)
reaction time of tertiary amine preparation is shortened from 6 h to 7 min; (c)
water instead of acetone was used as reaction medium; (d) toxic
by-products, wastewater and waste gas are eliminated. Flocculant made from the
synthesized high purity DADMAC monomers was proved more efficient in
flocculation tests.
Keywords: diallyldimethylammonium chloride, microwave irradiation, flocculant, cleaner process