环保型阻垢剂对水垢的抑制及其相互作用模拟

Inhibition of Scale by Environmentally Friendly Scale Inhibitor and the Interaction Simulation

为解决聚天冬氨酸(PASP)在高钙离子质量浓度下阻垢效果不佳及分散氧化铁效果差的问题,通过对中间体聚琥珀酰亚胺(PSI)开环改性将酪氨酸(Tyr)接枝到PASP的侧链,合成了具有羧基、氨基、酰胺基、酚羟基等多种功能性官能团的环保型阻垢剂——酪氨酸/聚天冬氨酸共聚物(Tyr-PASP)。静态阻垢实验表明Tyr-PASP对水垢的抑制能力明显优于PASP。当n(Tyr)∶n(PSI)=1∶1时,Tyr-PASP对CaCO3表现出最佳的抑制效果,且质量浓度为4 mg/L时阻垢效率达到了100%,在5 mg/L时,对CaSO4的抑制效率也达到100%。添加Tyr-PASP后,水垢晶形从稳定的方解石和文石变成了不稳定的球霰石,形貌也变得松散。分子动力学模拟表明,Tyr-PASP和方解石之间的相互作用是放热的,并且远高于传统的吸附能,静电力在Tyr/PASP和方解石之间的结合中起主要作用。此外,Tyr-PASP对氧化铁的分散效果显著提高。

In order to solve the problem that polyaspartic acid(PASP)has poor scale inhibition effect at high Ca^2+ concentration and poor effect of dispersing iron oxide,tyrosine(Tyr)was grafted to the side chain of PASP by ring-opening modification of the intermediate polysuccinimide(PSI).An environmentally friendly scale inhibitor of tyrosine-polyaspartic acid copolymer(Tyr-PASP)was synthesized and possessed a plurality of functional groups such as carboxyl group,amino group,amide group and phenolic hydroxyl group.The static scale inhibition experiment proved that Tyr-PASP possessed a better scale inhibition ability than PASP.When the molar ratio of n(Tyr)∶n(PSI)=1∶1,Tyr-PASP showed the best scale inhibition effect against CaCO3,and the inhibition efficiency reached up to 100% with a mass concentration of 4 mg/L.At 5 mg/L,the inhibition efficiency against CaSO4 also achieved 100%.After the addition of Tyr-PASP,the crystal form of scale changed from stable calcite and aragonite to unstable vaterite,and the morphology became loose.Molecular dynamics simulations show that the binding between Tyr/PASP and calcite is exothermic and the binding energy is much higher than that of conventional adsorption energy.Electrostatic forces play a major role in the binding between Tyr-PASP and calcite.In addition,the dispersion effect of Tyr-PASP on iron oxide is also significantly improved.