Calcium Sulfate Formation on Different Zwitterionic Amphiphilic Copolymer Substrates for Salt Water Treatment
Calcium Sulfate Formation on Different Zwitterionic Amphiphilic Copolymer Substrates for Salt Water Treatment
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DOI：
10.1021/acsapm.2c01014
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发表时间：
2022-09
影响因子：
5
通讯作者：
M. Wang;H. Nguyen;Samuel J. Lounder;A. Asatekin;D. Rodrigues
中科院分区：
文献类型：
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作者：
M. Wang;H. Nguyen;Samuel J. Lounder;A. Asatekin;D. Rodrigues
两性离子（ZI）聚合物是一类很有前途的防污防垢涂层材料。然而，其矿物结垢预防机制仍不清楚，这阻碍了ZI聚合物的应用。为了填补这一知识空白，我们研究了使用自由基聚合（FRP）由两性离子单体和疏水单体的不同组合合成的不同类型的ZI两亲性共聚物（ZAC）的结垢机制。所选的ZAC包括聚(甲基丙烯酸三氟乙酯-无规磺基甜菜碱甲基丙烯酸酯)(PTFEMA-r-SBMA,缩写为PT:SBMA)、聚(甲基丙烯酸三氟乙酯-无规-2-甲基丙烯酰氧基乙基磷酰胆碱)(PTFEMA-r-MPC,缩写为PT:MPC)、聚(甲基丙烯酸甲酯-无规磺基甜菜碱甲基丙烯酸酯)(PMMA-r-SBMA,缩写为PM:SBMA)和聚(甲基丙烯酸甲酯-随机-2-甲基丙烯酰氧基乙基磷酰胆碱)(PMMA-r-MPC，缩写为PM:MPC)。在具有不同饱和指数的模拟苦咸水溶液中测试这些聚合物涂层的硫酸钙 (CaSO4) 结垢情况，饱和指数定义为通过石膏溶解度常数 (Ksp) 归一化的实际溶解离子乘积（Q，即钙和硫酸根离子）的对数。这些实验结果表明，在高饱和指数（SI）下，ZAC涂层上的结垢沉积主要取决于表面能。因此，具有最低表面能的PT:SBMA涂层表现出更好的抗结垢性。在较低 SI 下，ZAC 涂层的亲水性是主导因素。由于含有MPC的ZAC涂层具有较高的表面亲水性，与含有ZAC的SBMA相比，它们可能具有相对较慢的结垢离子吸附速率，因此不会显着富集MPC涂层表面附近的结垢离子，从而抑制异质CaSO4沉淀。结果表明，ZAC 涂层的选择应考虑给水化学性质，除了有机污垢外，还应重点关注最佳的结垢预防效果。
Zwitterionic (ZI) polymers are a promising class of fouling-resistant and antiscaling coating materials. However, their mineral scaling prevention mechanism is still not well understood, which hampers the applications of ZI polymers. To fill this knowledge gap, we investigated the scaling mechanisms of different types of ZI amphiphilic copolymers (ZACs) synthesized from diverse combinations of zwitterion monomers and hydrophobic monomers using free-radical polymerization (FRP). The selected ZACs included poly(trifluoroethyl methacrylate-random-sulfobetaine methacrylate) (PTFEMA-r-SBMA, shortened as PT:SBMA), poly(trifluoroethyl methacrylate-random-2-methacryloyloxyethyl phosphorylcholine) (PTFEMA-r-MPC, shortened as PT:MPC), poly(methyl methacrylate-random-sulfobetaine methacrylate) (PMMA-r-SBMA, shortened as PM:SBMA), and poly(methyl methacrylate-random-2-methacryloyloxyethyl phosphorylcholine) (PMMA-r-MPC, shortened as PM:MPC). Coatings of these polymers were tested for calcium sulfate (CaSO4) scaling in simulated brackish water solutions with different saturation indices, defined as the logarithm of the actual dissolved ion product (Q, i.e., calcium and sulfate ions) normalized by the solubility constant of gypsum (Ksp). These experimental results indicated that at high saturation indices (SI), the scaling deposition on ZAC coatings mainly depended on the surface energy. Therefore, PT:SBMA coatings, which had the lowest surface energy, exhibited better-scaling resistance. At lower SI, the hydrophilicity of the ZAC coatings was the dominant factor. Since ZAC coatings containing MPC have higher surface hydrophilicity, they might have a relatively slower scale-forming ion adsorption rate compared to SBMA containing ZACs, thus not markedly enriching the scale-forming ion near MPC coating surfaces and hence inhibiting heterogeneous CaSO4precipitates. The results demonstrated that the selection of ZAC coatings should consider the feed water chemistry and focus on the optimal prevention of scaling in addition to organic fouling.