【作者】 陈丽华；

【导师】 罗芳；

【作者基本信息】 东北师范大学 ， 无机化学， 2010， 硕士

【摘要】 本论文以我国常见的生物废料桔皮作为原料,利用其中的有效成分,如纤维素等,在酸、碱化学修饰的基础上,将Cyanex272固定在已修饰的桔皮纤维素类吸附剂中,分别制得了六种吸附剂,并研究了它们对重金属Pb(Ⅱ)和Cd(Ⅱ)的吸附能力。我们讨论了吸附机理,考察了溶液的酸度值、接触时间、初始浓度、固液比等因素对重金属离子吸附平衡的影响,从中寻找最佳的吸附条件和解吸附条件,使我们就固定Cyanex272的桔皮纤维素类吸附剂对重金属离子的吸附性能有了较充分的认识,并得到如下结论：1.将Cyanex272成功地固定在大孔网络结构和高比表面积桔皮纤维素类吸附剂中,对Pb(Ⅱ)和Cd(Ⅱ)的吸附能力显著增强。吸附机制主要是离子交换和表面络合。2.不同的吸附剂对Pb(Ⅱ)吸附的最佳pH值范围是5.0-6.0之间,他们的吸附能力的顺序为：272SCO>SCO>272OP>272CO>OP,其中当pH=5.8时,272SCO对Pb(Ⅱ)的去除率为100%。对Cd(Ⅱ)吸附的最佳pH值范围是5.5-6.0之间,各种吸附剂的吸附能力的顺序为：272SCO>SCO>272OP>272CO>CO>OP,其中当pH值为5.5-6.0时,272SCO对Cd(Ⅱ)的去除率为100%。3.CO和SCO对浓度为0.001 mol·l-1的Pb(Ⅱ)吸附需要超过60分钟才能达平衡,而272OP、272CO和272SCO将平衡时间缩短至40分钟以下。272SCO对0.001 mol·l-1的Cd(Ⅱ)吸附只需在1分钟内就达到平衡,而SCO需要6分钟；此外,272CO平衡时间也由CO的40分钟降至25分钟。所有的吸附剂对Pb(Ⅱ)和Cd(Ⅱ)吸附反应动力学都遵循准二级反应动力学模型。4.不同吸附等温线模型的比较显示,对Pb(Ⅱ)采用Langmuir-Freundlich吸附等温线模型拟合的效果最好。基于Langmuir-Freundlich模型拟合的qm值的大小顺序为：272SCO (1.30 mol·kg-1)>SCO(1.26 mol·kg-1)>272CO(1.20 mol·kg-1)>272OP(1.02 mol·kg-1)> CO (0.62 mol·kg-1)。对Cd(Ⅱ)采用Langmuir吸附等温线模型拟合效果最好,基于Langmuir模型拟合的qm值的大小顺序为272SCO (0.8663 mol·kg-1)>SCO(0.6909 mol·kg-1)> 272CO 0.6873 mol·kg-1)>272OP(0.6853 mol·kg-1).5.当Pb(Ⅱ)初始浓度为0.002 mol·l-1时,272SCO从其中吸附Pb(Ⅱ)的最佳固液比为3.7 g·l-1。Cd(Ⅱ)初始浓度为0.002 mol·l-1时,272SCO从其中吸附Cd(Ⅱ)的最佳固液比为3.67 g·l-1。6.0.1 mol·l-1的盐酸被视为272SCO的最佳解吸剂,解吸率几乎是100%。更多还原

【Abstract】 In this paper, resourceful orange peel in our country, whose effective element is cellulose, has been used as the material.After modifying with acid or alkali, Cyanex272 has been immobilizing on the orange peel. Therefore, six types of adsorbents were prepared and use to examined the adsorption capacity to Pb(Ⅱ) and Cd(Ⅱ).The biosorption of Pb(Ⅱ) and Cd(Ⅱ) on modified orange peel have been investigated. Effects of solution pH, contact time, initial concentration and solid-quid ratio were also investigated. From these we can find the best conditions for adsorption and desorption. Therefore, we get fully recognize about the adsorption capacity of the adsorbent which were immobilized Cyanex272 on orange peel.The conclusions as follow:1.Cyanex272 is successfully immobilized on orange peel biosorbents with macroporous network structure and high specific surface area. Adsorption capacities of cadmium and lead onto orange peel were enhanced and equilibrium time has been reduced. Biosorption mechanism is regarded as a combination of the ion exchange and surface complexation.2. Adsorption of Pb(Ⅱ) strictly depends on pH, the optimum pH for the Pb(Ⅱ) adsorption process is in the range of 5.0-6.0 for all adsorbents and the order of adsorption capacity is: 272SCO>SCO>272OP>272CO>OP, the removal rate of Pb(Ⅱ) by 272SCO could be up to 100% at pH=5.8.The optimum pH for the Cd(Ⅱ) adsorption process is in the range of 5.5-6.0 for all adsorbents and the order of adsorption capacity is:272SCO>SCO>272OP >272CO>CO>OP, the removal rate of Cd(Ⅱ) by 272SCO could be up to 100% at pH 5.5-6.0.3. Biosorption equilibrium on adsorption of Pb(Ⅱ) was obtained after 60 min on CO and SCO when the concentration of metal solution was 0.001 mol·l-1.equilibrium time has been reduced to 40 min on 272OP,272CO and 272SCO. Biosorption equilibrium on adsorption of Cd(Ⅱ) was established quickly in 6 min and 1 min on SCO and 272SCO, respectively. Besides, equilibrium time has been reduced from 40 min (CO) to 25 min (272CO). Biosorption process of all adsorbents followed the pseudo-second-order mode4. A comparison of different isotherm models revealed:Langmuir and Freundlich (L-F) isotherm model fitted experimental data of Pb (Ⅱ) best, the order of maximum capacities is: 272SCO(1.30 mol·kg-1)>SCO(1.26 mol·kg-1)>272CO(1.20 mol·kg-1)>272OP(1.02 mol·kg-1)>CO (0.62 mol·kg-1).Langmuir isotherm fits the experimental data of Cd(Ⅱ) best, the order of maximum adsorption capacities is:272SCO (0.8663 mol·kg-1)>SCO (0.6909 mol·kg-1)>272CO(0.6873 mol·kg-1)>272OP (0.6853 mol·kg-1).5.The optimum s/1 ratio of Pb(Ⅱ) was 3.7 g·l-1 with 272SCO, that of Cd(Ⅱ) was 3.67 g·l-1 in 0.002 mol·l-1 solution.6. For the study of regeneration,272SCO was used to remove Pb(Ⅱ) and Cd(Ⅱ).0.1 mol·l-1 HCl is regarded as the optimum desorption agent, and the percentage of desorption is almost 100%.更多还原