Department of Chemistry, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montreal, QC H3C 3J7, Canada.
Environ Sci Process Impacts. 2015 Mar;17(3):674-82. doi: 10.1039/c4em00620h.
Sewage sludge sorption and desorption measurements were conducted for nine diverse contaminants of varying polarity: caffeine, sulfamethoxazole, carbamazepine, atrazine, estradiol, ethinylestradiol, diclofenac, and, for the first time desethylatrazine and norethindrone. Two types of sorption behaviour were observed. Compounds with a log octanol-water partition coefficient, log Kow, below 3 showed little or no sorption over 48 hours of shaking, while compounds with log Kow over 3 showed 30 to 90% sorption within the first few minutes. After 6 hours of shaking, mass loss through suspected biotransformation became evident for some compounds. At the pH range considered (5.7-6.7), diclofenac (pKa 4.0, log Kow 4.5) was the only compound in which pH dependent sorption could be quantified. The log sewage sludge-water distribution coefficients, log Kd, ranged from 0.2 to 2.9, and, as expected, increased with increasing log Kow of the compound and organic carbon (OC) content of the sewage sludge. A sewage sludge precipitated with alum had a substantially lower Kd values, as well as lower OC content, compared to alum-free sludge. Desorption was studied by sequentially replacing supernatant water. With each water replacement, log Kd values tended to either remain similar (following a linear isotherm) or in some cases increase (following a Freundlich-type isotherm). The length of time required to restore equilibrium increased with each rinsing step. A literature review of reported Kd values compared well with the alum-free sludge data, but not the alum-sludge data. Sewage sludge Kd across the literature appear more consistent with increasing Kow.
进行了九种不同极性污染物（咖啡因、磺胺甲恶唑、卡马西平、莠去津、雌二醇、乙炔雌二醇、双氯芬酸，以及首次研究的去乙基莠去津和炔诺酮）的污水污泥吸附和解吸测量。观察到两种类型的吸附行为。在 48 小时的摇晃过程中，具有小于 3 的 log 辛醇-水分配系数（log Kow）的化合物表现出很少或没有吸附，而具有大于 3 的 log Kow 的化合物在最初几分钟内表现出 30%至 90%的吸附。在摇晃 6 小时后，一些化合物通过疑似生物转化导致质量损失变得明显。在所考虑的 pH 范围内（5.7-6.7），只有在 pH 依赖吸附可以量化的情况下，双氯芬酸（pKa 为 4.0，log Kow 为 4.5）是唯一的化合物。污水污泥-水分配系数（log Kd）的范围从 0.2 到 2.9，并且与化合物的 log Kow 和污水污泥中的有机碳（OC）含量增加成正比。与不含明矾的污泥相比，用明矾沉淀的污水污泥的 Kd 值要低得多，OC 含量也低得多。通过顺序替换上清液来研究解吸。每次更换水时，log Kd 值往往要么保持相似（遵循线性等温线），要么在某些情况下增加（遵循 Freundlich 型等温线）。每次冲洗步骤所需的恢复平衡的时间都增加了。对文献中报告的 Kd 值的综述与无明矾污泥数据很好地吻合，但与明矾污泥数据不一致。文献中报道的污水污泥 Kd 值似乎更符合 Kow 的增加。
