School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0512, USA.
Water Res. 2010 Apr;44(7):2303-13. doi: 10.1016/j.watres.2009.12.029. Epub 2009 Dec 28.
The sorptive behavior of four quaternary ammonium compounds (QACs) - hexadecyl trimethyl ammonium chloride (C(16)TMA), dodecyl trimethyl ammonium chloride (C(12)TMA), hexadecyl benzyl dimethyl ammonium chloride (C(16)BDMA), and dodecyl benzyl dimethyl ammonium chloride (C(12)BDMA) - to municipal primary, waste activated, mesophilic digested, and thermophilic digested sludges was assessed at 22 degrees C. Batch adsorption of all four separately tested QACs to primary sludge reached equilibrium within 4h. At a nominal, initial QAC concentration of 300mg/L and a sludge volatile solids concentration of 1g/L, the extent of adsorption was 13, 88, 67, and 89% for the C(12)TMA, C(16)TMA, C(12)BDMA, and C(16)BDMA, respectively, and correlated positively to the QAC hydrophobicity and negatively to their critical micelle concentration. Equilibrium partitioning data were described by the Freundlich isotherm model. The adsorption capacity of the four sludges was very similar. In binary QAC mixtures, QACs with relatively high adsorption affinity and at relatively high aqueous concentrations decreased the adsorption of QACs with a low adsorption affinity. At pH 7, about 40% of the sludge-C(12)TMA desorbed, whereas less than 5% of the sludge-C(16)BDMA desorbed in 10 days. The effect of pH was negligible on the desorption extent of C(12)TMA at a pH range 4-10 over 10 days, whereas increasing the solution pH to 10 resulted in more than 50% desorption of C(16)BDMA. Given the fact that approximately 50% of the municipal biosolids are land-applied in the US, the data of this study would help in the assessment of the fate of QACs and their potential effect on human and environmental health.
在 22°C 下，评估了四种季铵化合物（QACs）-十六烷基三甲基氯化铵（C（16）TMA）、十二烷基三甲基氯化铵（C（12）TMA）、十六烷基苄基二甲基氯化铵（C（16）BDMA）和十二烷基苄基二甲基氯化铵（C（12）BDMA）对城市原污泥、废活性污泥、中温消化污泥和高温消化污泥的吸附行为。所有四种单独测试的 QAC 对原污泥的吸附在 4 小时内达到平衡。在名义上，初始 QAC 浓度为 300mg/L，污泥挥发性固体浓度为 1g/L 时，C（12）TMA、C（16）TMA、C（12）BDMA 和 C（16）BDMA 的吸附程度分别为 13%、88%、67%和 89%，与 QAC 的疏水性呈正相关，与临界胶束浓度呈负相关。平衡分配数据符合 Freundlich 等温线模型。四种污泥的吸附容量非常相似。在二元 QAC 混合物中，具有相对较高吸附亲和力和相对较高水相浓度的 QAC 降低了具有低吸附亲和力的 QAC 的吸附。在 pH 7 下，约 40%的污泥-C（12）TMA 解吸，而在 10 天内，少于 5%的污泥-C（16）BDMA 解吸。在 4-10 范围内，pH 值对 C（12）TMA 在 10 天内的解吸程度影响可忽略不计，而将溶液 pH 值提高到 10 会导致 C（16）BDMA 的解吸超过 50%。鉴于美国约有 50%的城市生物固体用于土地应用，本研究的数据将有助于评估 QAC 的命运及其对人类和环境健康的潜在影响。
