Eskişehir Osmangazi University, Department of Chemical Engineering, Turkey.
J Environ Manage. 2010 Jan-Feb;91(3):724-31. doi: 10.1016/j.jenvman.2009.09.036. Epub 2009 Oct 21.
In the present study, the sorption characteristics of Cd(II) and Zn(II) ions on quartz, a representative soil-component, and the desorption of these metal ions from quartz using rhamnolipid biosurfactant were investigated. In the first part of the studies, the effects of initial metal ion concentration and pH on sorption of Cd(II) and Zn(II) ions by a fixed amount of quartz (1.5g) were studied in laboratory batch mode. The equilibrium sorption capacity for Cd(II) and Zn(II) ions was measured and the best correlation between experimental and model predicted equilibrium uptake was obtained using the Freundlich model. Although investigations on the desorption of heavy metal ions from the main soil-components are crucial to better understand the mobility and bioavailability of metals in the environment, studies on the description of desorption equilibrium were performed rarely. In the second part, the desorption of Cd(II) and Zn(II) from quartz using rhamnolipid biosurfactant was investigated as a function of pH, rhamnolipid concentration, and the amounts of sorbed Cd(II) and Zn(II) ions by quartz. The Freundlich model was also well fitted to the obtained desorption isotherms. Several indexes were calculated based on the differences of the quantity of Cd-Zn sorbed and desorbed. A desorption hysteresis (irreversibility) index based on the Freundlich exponent, concentration-dependent metal distribution coefficients, and the irreversibility index based on the metal distribution coefficient were used to quantify hysteretic behavior observed in the systems.
在本研究中，研究了 Cd(II)和 Zn(II)离子在石英（一种典型的土壤成分）上的吸附特性，以及用鼠李糖脂生物表面活性剂从石英上解吸这些金属离子的情况。在研究的第一部分，采用实验室间歇法研究了初始金属离子浓度和 pH 值对一定量石英（1.5g）吸附 Cd(II)和 Zn(II)离子的影响。测量了 Cd(II)和 Zn(II)离子的平衡吸附容量，并使用 Freundlich 模型获得了实验和模型预测平衡吸附量之间的最佳相关性。虽然研究主要土壤成分中重金属离子的解吸对于更好地了解金属在环境中的迁移性和生物可利用性至关重要，但对解吸平衡的描述研究却很少。在第二部分，研究了 pH 值、鼠李糖脂浓度以及石英吸附的 Cd(II)和 Zn(II)离子量对用鼠李糖脂生物表面活性剂从石英上解吸 Cd(II)和 Zn(II)离子的影响。也用 Freundlich 模型很好地拟合了得到的解吸等温线。基于吸附和解吸的 Cd-Zn 量的差异，计算了几个指标。根据 Freundlich 指数、浓度依赖性金属分配系数和基于金属分配系数的不可逆性指数，提出了一种用于量化体系中观察到的滞后行为的解吸滞后（不可逆性）指数。
