Synthesis And Silica Scale Inhibition Perfoormance Of Dendritic Polyamidoamine

The aim of this thesis is to select and develop a high efficient scale inhibitor for colloidal silica and silicon scale in water treatment process in order to reduce water treatment cost.Linear copolymer scale inhibitors YSM 11 and other four linear copolymer inhibitors were investigated the inhibition of colloidal silica and silicon scale in initial soluble silica concentration approximal 500mg·L^-1.PAMAM 0.5～3.0 have been synthesized by divergent method with ethylenediamine and methyl acrylate as raw stuff and methyl alcohol as solvent,and the structures were characterized with IR and NMR, and the optimum synthesis condition of PAMAM 0.5 and PAMAM 1.0 were confirmed by orthogonal experiments.At last,the inhibition of colloidal silica and silicon scale of PAMAM 0.5～3.0 were investigated statically in initial soluble silica concentration approximally 500mg·L^-1.In neutral solutions with initial soluble silica concentration approximal 500mg·L^-1,the silica scale inhibition of five linear copolymer inhibitors is:all of five inhibitors have little inhibition for the colloidal silica scale.At the conditions of pH 7±0.05 and initial SiO₂ concentration approximally 500mg·L^-1and Ca²⁺and Mg²⁺concentration 800mg·L^-1individually,solutions dosed with YSM 11 concentration 100mg·L^-1,the concentration of soluble silica only dropped to 411.4mg·L^-1and 315.9mg·L^-1individually after 30h.As a scale-inhibitor YSM 11 possesses quite good effect on controlling silicon scale.In the process of synthesis of PAMAM,the optimum synthesis condition of PAMAM 0.5 and PMAM 1.0 are confirmed by oxthoyonal experiments and the detail are:PAMAM 0.5:methyl acrylate exceeding 100%(relative ethylenediamine),synthetic temperature 35℃and the synthesis time 24h,at these conditions the synthesis effectivessness of PAMAM 0.5 could reach 99.90%or more;PAMAM 1.0:the amount of ethylenediamine exceeding 100%(relative PAMAM 0.5),synthetic temperature 30℃and the synthetic time 16h,at the conditions the synthesis effectivessness could reach 99.80%.In solutions pH 7 + 0.05 and initial soluble silica concentration approximal 500mg·L^-1,colloidal silica scale can be controlld by PAMAM 0.5～3.0 individually.Under the condition of PAMAM 1.0 concentration 50mg·L^-1in the neutral solutions,soluble silica concentration only dropped to 400mg·L^-1after 30h.The silica inhibition ability of PAMAM 1.0 was better than other generations' of PAMAM.In neutral solutions with initial soluble silica concentration approximal 500mg·L^-1,the silicon scale inhibition of PAMAM 0.5 and PAMAM 1.0 are s follows:PAMAM 0.5 has little inhibition for the calcium silicate and magnesium silicate scale;at the conditions of pH 7±0.05 and initial SiO₂ concentration approximally 500mg·L^-1and Ca²⁺and Mg²⁺concentration 800mg·L^-1individually,solutions dosed with PAMAM 1.0 concentration 30mg·L^-1,the concentration of soluble silica only dropped to 364.9mg·L^-1and 394.5mg·L^-1individually after 30h.