Study on preparation and application in decolorizing simulative dyeing wastewater of amphoteric lignin-based flocculant

The amphoteric lignin-based flocculant(LSM) was synthesized through graft acrylamide to calcium lignosulphonate and cationizing modification,influence of molar ratio of formaldehyde to dimethylamine,reaction temperature,reaction time on cationizing reaction were studied.The LSM was used to decolor various simulating dye effluents,e.g.,reactive blue X-BR,reactive yellow X-R,reactive violet K-3R,reactive black K-BR,influence of dosage of LSM,pH of waste water on the decolorizing effect of LSM and the influence of the dosage of LSM on the CODcr of the waste water were studied.The results shows that LSM has good decoloration performance under the condition that molar ratio of formaldehyde to dimethylamine is 1 ∶1,θ1=50 ℃,t1=1.0 h,θ2 =50 ℃,t2 =2.0 h.The decoloration rate of LSM to the four kinds of simulative dyeing wastewater are all above 82%,but the CODcr of the waste water will increase while the dosage of LSM increased,so the dosage of LSM should be controlled in proper range in practical use.