改性双氰胺-甲醛絮凝剂的制备与性能研究

Preparation and Properties of Modified Dicyandiamide-Formaldehyde Flocculant

为改善双氰胺-甲醛絮凝剂(DCDF)沉降慢、对废水pH适应性差等不足,扩大其在污水处理领域中的运用,采用对氨基苯磺酸钠进行改性,合成了一种两性脱色絮凝剂SPAS-DCDF。考察了投加量、废水初始pH值等对染料脱色效果的影响,结果表明改性后的双氰胺-甲醛絮凝剂对活性红X-3B的脱色率显著上升,在酸性至弱碱性的条件下均保持良好的脱色絮凝效果。对吸附过程进行了吸附等温线和吸附动力学模型拟合,探究了吸附反应的机理,结果表明,吸附过程为单分子层主导的化学吸附,吸附速率由表面吸附点位与内扩散共同控制,理论平衡吸附量为1.2675 mg/mg,吸附过程分为三个阶段,k_(p 1)、k_(p 2)和k_(p 3)分别为0.14,0.057和0.0064 mg/(mg·min^(1/2))。

In order to improve the shortcomings of dicyandiamide-formaldehyde flocculant(DCDF)such as slow sedimentation and poor adaptability to wastewater pH,and expand its application in the field of sewage treatment,sodium p-aminobenzene sulfonate was used to modify and synthesize an amphoteric decolorizing flocculant SPAS-DCDF.The effects of dosage and initial pH of wastewater on the decolorization effect of dyes were investigated.The results showed that the decolorization rate of Reactive Red X-3B by the SPAS-DCDF increased significantly,and it maintained good decolorization and flocculation effect under the conditions of acidity to weak alkalinity.The adsorption process was fitted with adsorption isotherm and adsorption kinetic model to explore the mechanism of adsorption reaction.The results showed that the adsorption process was chemical adsorption dominated by single layer monolayer.The adsorption rate was jointly controlled by surface adsorption sites and internal diffusion,and the theoretical equilibrium adsorption capacity was 1.2675 mg/mg,The adsorption process is divided into three stages,with k_(p 1),k_(p 2),and k_(p 3)being 0.14,0.057 and 0.0064 mg/(mg·min^(1/2)),respectively.