以烯丙基聚乙二醇单醚、氯乙酸、氢氧化钠、马来酸酐等为原料制备了一种新型无磷无氮环保型阻垢剂马来酸酐/烯丙基聚乙二醇羧酸钠(MCn,n为聚乙二醇聚合度,n=5、9、13),用红外光谱(FT-IR)、核磁共振(1H-NMR)等对阻垢剂结构进行了表征,采取静态阻垢率和含Fe(Ⅲ)溶液透光率的方法考察了阻垢剂阻磷酸钙和分散Fe(Ⅲ)性能,用扫描电镜(SEM)观察了阻垢后形成的磷酸钙形貌。结果表明,随着MCn结构中聚乙二醇聚合度n从5增加到13,其阻磷酸钙垢性能和分散Fe(Ⅲ)效果也逐步提高,其中MC13在投加量为6mg·L-1时阻磷酸钙垢率达99%,在投加量为8mg·L-1时使含Fe(Ⅲ)溶液的透光率为22%。MCn的高效阻磷酸钙垢和分散Fe(Ⅲ)能力是源于其侧链上含有聚乙二醇单醚结构及存在大量的—COO-离子且易与循环水系统中存在的不同的无机金属离子发生作用。
A novel phosphorus-free and nitrogen-free anti-scalant for calcium phosphate and Fe(Ⅲ),maleic anhydride/allyl polyethylene glycol carboxylate(MCn,n is the degree of polymerization of polyethylene glycol,n=5,9,13),was synthesized from allyl polyethylene glycol monoether,chloracetic acid,maleic anhydride,and sodium hydroxide.The product was characterized by FT-IR and 1H-NMR.The performance of calcium phosphate inhibition and dispersancy towards Fe(Ⅲ)was evaluated by the static scale-inhibiting method and light transmittance,respectively.SEM analysis showed a disordered calcium phosphate crystal in the presence of MCn.The studies indicated that both inhibition and dispersancy increased with increasing degree of polymerization of polyethylene glycol in the structure of MCn from 5 to 13.MC13 had superior ability to inhibit the precipitation of calcium phosphate,approximately 99% inhibition when the dosage was 6 mg·L-1,and had excellent dispersancy towards Fe(Ⅲ),about 22% light transmittance when the dosage was 8 mg·L-1.Inhibition mechanism was proposed that the interactions between all kinds of metallic ions in systems and carboxyl groups on side chains and/or oxygen atoms of ethers were the fundamental impetus to restrain the formation of calcium phosphate scale and disperse Fe(Ⅲ)in cooling water systems.