Department of Chemical Engineering & Technology, Panjab University, Chandigarh 160014, India.
J Hazard Mater. 2009 Nov 15;171(1-3):1009-15. doi: 10.1016/j.jhazmat.2009.06.107. Epub 2009 Jun 26.
The breakthrough curves for Hg(II) ions on a sample of granulated activated carbon (GAC) and a sample of activated carbon cloth (ACC) are generally S-shaped. The breakthrough time increases with increase in the bed depth but decreases on increasing the hydraulic loading rate (HLR) and the feed concentration. The adsorption of Hg(II) ions increases with HLR and attains a maximum value at HLR around 7m(3)/h/m(2). At low HLR, laminar flow conditions prevail so that the mass transfer takes place across a nearly stationary film of the liquid covering the carbon particles. This high resistance leads to low mass transfer and results in smaller adsorption. On increasing HLR, the interface resistance decreases resulting in an increase in adsorption. Beyond a certain HLR, the rate of adsorption decreases due to decrease in the residence time of the solution within the carbon bed and a lower time available for mass transfer. The adsorption zone parameters of the carbon column have been determined using the carbon bed column data and invoking the mathematical treatment suggested by Michaels. Bed Depth Service Time (BDST) theoretical model has been used to calculate the critical bed depth and the depth of the mass transfer zone. These have been found to be in agreement with the experimental values.
颗粒状活性炭（GAC）和活性炭布（ACC）上 Hg(II)离子的穿透曲线通常呈 S 形。随着床层深度的增加，穿透时间增加，但随着水力负荷率（HLR）和进料浓度的增加而减少。Hg(II)离子的吸附随 HLR 增加而增加，并在 HLR 约 7m³/h/m²时达到最大值。在低 HLR 下，层流条件占主导地位，因此质量传递发生在覆盖碳颗粒的几乎静止的液体薄膜上。这种高阻力导致传质低，从而导致吸附减少。随着 HLR 的增加，界面阻力降低，导致吸附增加。超过一定的 HLR，由于溶液在碳床内的停留时间减少以及传质的可用时间减少，吸附速率降低。使用碳床柱数据并调用 Michaels 提出的数学处理方法，确定了碳柱的吸附区参数。已使用床层深度服务时间（BDST）理论模型来计算临界床层深度和传质区深度。这些发现与实验值相符。
