Marine Chemistry Lab., National Institute of Oceanography and Fisheries, Suez branch, Adabiyah-Suez road, Attaqa district, Suez, Egypt.
Department of Water Research, National Research Centre, 33 El Bohouth st. (former Eltahrir st.), P.O. 12622, Dokki, Giza, Egypt.
Sci Rep. 2019 Mar 4;9(1):3356. doi: 10.1038/s41598-019-39945-1.
Dead leaves of seagrass Posidonia oceanica were activated by using one mol L acetic acid and used as an eco-adsorbent for the removal of methylene blue (MB) and Pb from aqueous solutions. The seagrass was characterized by chemical and physical measurements that confirmed the acid-activation of seagrass. The favourable conditions for MB and Pb adsorption onto the activated seagrass (SG) were determined to be a pH range of 2-12 and ≥6, an adsorbent dosage of 3.0 and 0.5 g L, respectively, and a shaking time of 30 min, which are suitable for a wide range of wastewaters. The equilibrium data were analysed using the Langmuir, Freundlich and Dubinin-Raduskavich-Kaganer (DRK) adsorption isotherm models. The Freundlich and DRK models best describe the adsorption processes of MB and Pb, on SG with capacities of 2681.9 and 631.13 mg g, respectively. The adsorption isotherm fitting and thermodynamic studies suggest that the adsorption mechanism of MB may combine electrostatic and physical multilayer adsorption processes, in which MB may be present as monomers as well as dimers and trimers which were confirmed from UV spectroscopy whereas Pb is chemically adsorbed onto SG. The pseudo-2-order kinetic model was utilized to investigate the kinetics of adsorption processes. The removal process was successfully applied for MB-spiked brackish waste water from Manzala Lake, Egypt, with removal efficiencies of 91.5-99.9%.
使用 1 mol/L 乙酸对海草波西多尼亚海洋草的枯叶进行活化，并将其用作生态吸附剂，从水溶液中去除亚甲基蓝 (MB) 和 Pb。通过化学和物理测量对海草进行了表征，证实了海草的酸化活化。确定了 MB 和 Pb 吸附到活化海草 (SG) 上的有利条件为 pH 值范围为 2-12 和≥6，吸附剂用量分别为 3.0 和 0.5 g/L，以及 30 min 的搅拌时间，这适用于广泛的废水。使用 Langmuir、Freundlich 和 Dubinin-Raduskavich-Kaganer (DRK) 吸附等温线模型对平衡数据进行了分析。Freundlich 和 DRK 模型最能描述 MB 和 Pb 在 SG 上的吸附过程，其容量分别为 2681.9 和 631.13 mg/g。吸附等温线拟合和热力学研究表明，MB 的吸附机制可能结合了静电和物理多层吸附过程，其中 MB 可能以单体以及二聚体和三聚体的形式存在，这从紫外光谱得到了证实，而 Pb 则被化学吸附到 SG 上。利用拟二级动力学模型研究了吸附过程的动力学。该去除过程成功应用于从埃及曼扎拉湖的含 MB 咸水废水中去除，去除效率为 91.5-99.9%。
