Pech - Dimethylamine Synthesis And Its Performance

With the rapid development of industry, the ingredients of printing and dyeing wastewater have become more and more intricate and in order to treat printing and dying wastewater efficiently, it is urgent that higher efficiency coagulants should be exploited.Here, polyamine flocculants were synthesized by polycondensation of dimethylamine and epichlorohydrin with modifying agents such as Diaminoethane. The influences of the kind and the amount of modifying agents, polymerization temperature, molar ratio of epichlorohydrin and dimethylamine, and polymerization time on the characteristics of polyamine flocculants were investigated. The results show that as for the cationicity and molecular weights of the polymers, the amount of modifying agents, polymerization temperature, molar ratio of epichlorohydrin and dimethylamine, and polymerization time all have an optimum value under certain polymerization conditions and that the kind of modifying agents has a great effect on the structure of the polymers. The structure of the polymer and its aggregation in aqueous solution were examined by means of various instrumental analysis techniques, including IR, NMR, Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM) respectively. At the end of the experiments, the flocculation efficiency of the polymers for dye liquor, printing and dyeing wastewater and oil refinery effluent and the flocculation efficiency of polyamine flocculants used with PAC were studied by jar test. The experimental results show that the cationicity, the molecular weight and the structure have a great effect on the flocculation efficiency of polyamine flocculants. In general, the larger the cationicity and molecular weight are, the better flocculation performance the polyamine flocculants have. However, the cationicity and molecular weight contradict with each other under certain conditions, that is to say the both characteristics can not be increased at the same time. Thus the cationicity and molecular weight should be geared to the difference of the printing and dyeing wastewater. Generally, for dispersed dyewastewater, polyamine flocculants perform mainly as aWsofpfipn bridging agents, while for water-soluble dye wastewater, polyamine flocculants show both charge neutralization and adsorption bridging functions. In conclusion, a certain kind of wastewater needs the flocculant with special structure. Using polyamine flocculants with PAC, not only shows better flocculation performance, but also can lower the water treatment cost. The polyamine flocculants function in the wastewater by charge neutralization and adsorption bridging mechanism. The experimental results show that polyamine polymers are organic flocculants with high performance and multi-function.