Study On The Graft Copolymerization Of Lignosulfonate And The Synthesis, Flocculation Property Of Lignin-base Amphoteric Flocculant LSDC

As a byproduct of wood hydrolyzing and paper making industry , lignin comes to the main polluting resource because of not taking full utilization, resulting in sever pollution as well as resource waste. With the opinion of effective utilization of lignin , graft copolymerization of lignosulfonate with acrylamide was studied. An amphoteric lignin-base flocculant LSDC was prepared by the Mannich reaction of the calcium lignosulfonate-acryamide copolymer. Then the flocculation properties and applications of LSDC were comprehensively studied. And the research on the mechnism of discoloration and flocculation was also carried out.The graft copolymerization of straw magnisum lignosulfonate and pine calcium lignosulfonate with acrylamide was studied. The optimun graft conditions was obtained by applying molecular weight, production rate and intrinsic viscosity as aim value individually. As for straw magnisum lignosulfonate, the suitable conditions include 0.5×10^-2 mol/L of K₂S₂O₈/ Na₂S₂O₃ initiator, 1.4 mol/L acrylamide monomer , 40 ℃ for 48 h, and 1:50 of liquor ratio. As for pine calcium lignosulfonate, the suitable conditions include 0.5 ×10^-2 mol/L of K₂S-2O₈ initiator, 1.4 mol/L acrylamide monomer , 50 ℃ for 2 h ,and 1:50 of liquor ratio. The graft copolymerization was further testified by IR, GPC, Py-GC-MS etc. After graft reaction molecular weight was evidently increased, and homogensity of molecular weight was improved. The ratio of low molecular weight was decreased obviously. There were probably three linked-ways: ether bond, salt bond and cross-linking.Application of lignosulfonate-acryamide copolymer in the decolorizing of cationic dye model wastewater was studied. It was concluded that the copolymer can be used as anion flocculant on the decolorizing of cationic dye model wastewater. As a decolorizing agent, the copolymer was more suitable for higher initial concentration and neutral condition. Good decolorization rate could be more than 85% under suitable dosage of copolymer. The enhancement of rate between lignosulfonate and acrylamide can not only reduce the cost but also improve the decolorization rate. At the same time, calcium lignosulfonate-acryamide copolymer had better decolorizing result than magnisum lignosulfonate-acryamide copolymer.An amphoteric lignin-base flocculant LSDC can be obtained by the Mannich reaction of calcium lignosulfonate-acryamide copolymer. Orthogonal experiments were conducted to study the affecting factors on the decolorization performances of...