Department of Civil and Environmental Engineering, Syracuse University , 151 Link Hall, Syracuse, New York 13244, United States.
Environ Sci Technol. 2015 Mar 3;49(5):2939-47. doi: 10.1021/es504024u. Epub 2015 Feb 9.
A variety of mathematical estimators have been used to quantify the degree of protonation of naturally occurring organic acids. These estimators range from monoprotic, diprotic, and triprotic analog models to the discrete and continuous (Gaussian) distributions of a single proton binding-dissociation. Natural water samples from two long-term monitoring programs in the northeastern U.S. were used to quantify proton- and aluminum-binding properties of naturally occurring organic matter. Water chemistry observations were clustered into 0.05 pH intervals (over 3.75-7.35 pH range) and fit to a triprotic analog model. The model optimization indicates that about 5% of dissolved organic carbon participates in ion binding, and organic acids are composed of both strong and weak acids (i.e., pKa1 = 2.54, pKa2 = 6.19, and pKa3 = 7.52 for Adirondack samples). Binding between organic acids and aluminum can substantially influence the acid behavior of dissolved organic matter and the availability of the toxic form of aluminum (i.e., inorganic monomeric aluminum).
已使用各种数学估算器来量化天然存在的有机酸的质子化程度。这些估算器的范围包括单质子、双质子和三质子模拟模型，以及单个质子结合-解吸的离散和连续（高斯）分布。美国东北部两个长期监测计划的天然水样被用于量化天然有机物的质子和铝结合特性。水化学观测值被聚类到 0.05 pH 间隔（在 3.75-7.35 pH 范围内），并拟合到三质子模拟模型。模型优化表明，约 5%的溶解有机碳参与离子结合，有机酸由强酸和弱酸组成（即，阿迪朗达克样品的 pKa1 = 2.54、pKa2 = 6.19 和 pKa3 = 7.52）。有机酸和铝之间的结合可以极大地影响溶解有机质的酸行为以及有毒形式的铝（即无机单体铝）的可用性。
