School of Civil Engineering, Hefei University of Technology, Hefei 230009, China.
J Hazard Mater. 2010 Jan 15;173(1-3):292-7. doi: 10.1016/j.jhazmat.2009.08.082. Epub 2009 Aug 25.
In this study, cattail root was used to remove Congo Red (CR) from aqueous solution. The effects of operation variables, such as cattail root dosage, contact time, initial pH, ionic strength and temperature on the removal of CR were investigated using batch adsorption technique. Removal efficiency increased with increase of cattail root dosage and ionic strength, but decreased with increase of temperature. The equilibrium data fitted well to the Langmuir model (R(2)>0.98) and the adsorption kinetic followed the pseudo-second-order equation (R(2)>0.99). Thermodynamics parameters such as standard free energy change (Delta G degrees), standard enthalpy change (Delta H degrees), and standard entropy change (DeltaS degrees ) were analyzed. The values of Delta G degrees were between -7.871 and -4.702 kJ mol(-1), of Delta H degrees was -54.116 kJ mol(-1), and of DeltaS degrees was -0.157 kJ mol(-1)K(-1), revealing that the removal of CR from aqueous solution by cattail root was a spontaneous and exothermic adsorption process. The maximum adsorption capacities of CR on cattail root were 38.79, 34.59 and 30.61 mg g(-1) at 20, 30 and 40 degrees C, respectively. These results suggest that cattail root is a potential low-cost adsorbent for the dye removal from industrial wastewater.
本研究利用香蒲根从水溶液中去除刚果红（CR）。采用批量吸附技术，考察了香蒲根用量、接触时间、初始 pH 值、离子强度和温度等操作变量对 CR 去除的影响。去除效率随香蒲根用量和离子强度的增加而增加，但随温度的升高而降低。平衡数据拟合Langmuir 模型（R²>0.98），吸附动力学符合拟二级方程（R²>0.99）。分析了热力学参数，如标准自由能变化（ΔG°）、标准焓变（ΔH°）和标准熵变（ΔS°）。ΔG°的值在-7.871 到-4.702 kJ mol（-1）之间，ΔH°的值为-54.116 kJ mol（-1），ΔS°的值为-0.157 kJ mol（-1）K（-1），表明香蒲根从水溶液中去除 CR 是一个自发的放热吸附过程。在 20、30 和 40°C 下，CR 在香蒲根上的最大吸附容量分别为 38.79、34.59 和 30.61 mg g（-1）。这些结果表明，香蒲根是一种潜在的低成本工业废水染料去除吸附剂。
