Department of Civil and Environmental Engineering, Stanford University , 473 Via Ortega, Stanford, California 94305, United States.
Environ Sci Technol. 2014 Nov 18;48(22):13392-401. doi: 10.1021/es504091s. Epub 2014 Nov 3.
Quaternary ammonium cationic polymers, such as poly(diallyldimethylammonium chloride) (polyDADMAC) are widely used for coagulating and removing negatively charged particles and dissolved organic matter (DOM) from drinking water. Their use, however, has been linked to the formation of carcinogenic N-nitrosamines as byproducts during chloramine-based drinking water disinfection. In this study, a novel quaternary phosphonium cationic polymer, poly(diallyldiethylphosphonium chloride) (polyDADEPC), was synthesized such that the quaternary nitrogen atom of polyDADMAC was substituted with a phosphorus atom. Formation potential tests revealed that even under strong nitrosation conditions, polyDADEPC and related lower-order P-based compounds formed oxygenated and not nitrosated products. Bench-scale jar tests using three different source waters further demonstrated that polyDADEPC achieved coagulation performance comparable to commercial polyDADMACs for particle and DOM removals within the typical dose range used for drinking water treatment. This work highlights the potential use of a phosphonium coagulant polymer, polyDADEPC, as a viable alternative to polyDADMAC to avoid nitrosated byproduct formation during chloramination.
季铵阳离子聚合物，如聚二烯丙基二甲基氯化铵（polyDADMAC），广泛用于混凝和去除饮用水中的带负电荷的颗粒和溶解有机物（DOM）。然而，它们的使用与在基于氯胺的饮用水消毒过程中作为副产物形成致癌的 N-亚硝胺有关。在这项研究中，合成了一种新型的季𬭸阳离子聚合物，聚二烯丙基二乙基𬭸氯化物（polyDADEPC），使得 polyDADMAC 的季氮原子被磷原子取代。形成潜力测试表明，即使在强亚硝化条件下，polyDADEPC 和相关的低阶 P 基化合物也形成了含氧而不是亚硝化的产物。使用三种不同原水的中试规模搅拌桶试验进一步表明，polyDADEPC 在饮用水处理中典型剂量范围内实现了与商业 polyDADMAC 相当的混凝性能，用于颗粒和 DOM 的去除。这项工作强调了使用季𬭸混凝聚合物 polyDADEPC 作为替代 polyDADMAC 的潜在可能性，以避免在氯胺化过程中形成亚硝化副产物。
