【作者】 杨蓉；

【导师】 赵芳； 周莹；

【作者基本信息】 中南林业科技大学 ， 应用化学， 2011， 硕士

【摘要】 吸附法是国内外应用较为广泛的一种废水处理方法,具有处理设备及工艺简单、适应的浓度范围广、不会造成二次污染等显著优点。在吸附法处理废水实践中,吸附剂与吸附质的准确定量计算问题长期以来未得到有效解决。基于一系列固／液相离子吸附体系的研究建立的四组分吸附模型,给出了吸附量与吸附剂浓度及吸附质浓度之间的定量关系,但是,至今只在离子吸附体系中得到验证。本文选用果壳活性炭作为吸附剂,在苯酚起始浓度50-1000 mg/L和吸附剂浓度5-25 g/L范围内,研究该吸附体系的平衡等温吸附过程及动力学过程,探讨四组分吸附模型在在分子吸附体系中的有效性和适应条件。主要研究结果如下：(1)利用农副产品加工生产的果壳活性炭能高效、快速地吸附去除废水中的苯酚,是一种很有前景的净水材料。温度对该吸附的影响不显著,在10-40℃范围内,吸附量随温度的升高而略有减小；溶液起始pH值对吸附量有显著影响,控制含酚废水溶液pH值在酸性至中性条件下有利于提高吸附去除率。(2)果壳活性炭对水溶液中苯酚的吸附体系中存在吸附剂浓度效应；经典的Langmuir与Freundlich等温方程参数不恒定为常数,而是随吸附质浓度C0和吸附剂浓度W0变化而不断发生变异,给W0、变化C0或给定C0、变化W0所获得的拟合参数用于比较不同吸附剂的吸附性能、或进行热力学估算都有可能导致错误结论。(3)果壳活性炭吸附水溶液中苯酚的规律符合四组分吸附模型,苯酚平衡吸附量和去除率由溶液中起始吸附质浓度C0和吸附剂浓度W0的相对水平决定,给定C0/W0比值,平衡吸附量具有唯一对应的值；由四组分吸附模型推导出的平衡吸附量预测方程可以准确地预测给定C0和W0条件下苯酚的吸附量,表明前人在一系列固液相离子吸附体系研究基础上提出的四组分吸附理论同样适用于分子吸附体系。(4) Lagergren准二级动力学方程能很好地拟合果壳活性炭吸附水溶液中苯酚的动力学过程,但其参数随C0和W0变化且不能确定其间的函数关系；基于四组分吸附理论推导得出的动力学方程与该实验数据吻合程度很高,其参数与C0和W0具有稳定的函数关系,可以作为给定C0、W0条件下果壳活性炭-苯酚吸附动力学过程的预测模型。本文证实了经典吸附理论在应用中存在吸附剂浓度效应、参数变异等问题,四组分吸附模型则可以有效地消除吸附剂的浓度效应,有效地解决了固／液相分子吸附过程中的定量计算准确性问题,为吸附法处理含苯酚废水的定量研究提供了理论依据。更多还原

【Abstract】 Adsorption is widely used in treating waste water at home and abroad, the obvious advantages of adsorption is that has simple equipment and technology, adaptive concentration range and will not cause secondary pollution. In the practice of treating waste water with adsorption, the accurate quantitative calculation of adsorbent and adsorbate is a long-standing problem that did not get settled. Four components adsorption model were established based on a series of solid/liquid ion adsorption system, which provided the quantitative relationships between adsorbed amount and the concentration of adsorbent and adsorbate, however it was only testified in ion adsorption system.This paper selected shell activated carbon as adsorbent, the initial concentration of phenol was 50-1000mg/L and the concentration of adsorbent was 5-25g/L, the equilibrium adsorption isotherm and dynamics process of this adsorption system was researched, the effectiveness and adaptive conditions of four components adsorption model in this system was also discussed. The main results are as follows:(1) Shell activated carbon produced from agricultural and sideline products is cheap and green, which could remove phenol from waste water by adsorption efficiently and quickly. So shell activated carbon is a kind of water-purifying material. Effect of temperature on phenol adsorption by shell activated carbon was not significant. The adsorption decreased with increasing temperature in 10-40℃. Effect of initial pH of solution on phenol adsorption was significant. It was good for improvementof removal ratio to make sure the pH of phenol waste water in acid and in neutral solution.(2) There was adsorbent effect in the adsorption system of shell activated carbon and phenol waste water. The parameters of classical Langmuir and Freundlich isotherm equation were not constant, but varied constantly with the changes of adsorbate concentration Co and adsorbent concentration Wo. Matching parameters obtained by given WO or Co would lead to wrong conclusions when they were used to compare adsorption performance of different adsorbent or thermodynamics estimate. (3) Patterns of phenol adsorption by shell activated carbon correspond with four components adsorption model. Equilibrium adsorption of phenol and removal rate were up to the relative level of adsorbate concentration Co and adsorbent concentration W0 Equilibrium adsorption represented a unique value that corresponded to a given ratio of Co and W0. Equilibrium adsorption predicting equation derived from four components adsorption model could forecast the phenol adsorption in the condition of given ratio of Co and Wo, indicating four components adsorption model putted forward by predecessors on the basis of series solid and liquid phase ion adsorption research was the same applies to molecule adsorption systems.(4) The Lagergren quasi secondary dynamic equation can well fitted kinetics ion adsorption process in aqueous solution for adsorption of phenol on shell activated carbon, but its parameters can’t ascertain the function relation between them with Co and Wo changing. Dynamic equation obtained based on four adsorption components theory model has high identical degree with the experimental data and parameters Co and W0 remain nearly constant in the tested range, indicating that given Co and W0, the presented equation can be used to describe the kinetic molecular adsorption process for phenol adsorptions on shell activated carbon in solutions.The results proved that there were problem of adsorbent effect、parameters variation in the use of classical adsorption theory, and four components adsorption model could eliminate adsorbent effect effectively, which effectively solve the problem of accuracy in the quantitative calculation of solid and liquid phase ion adsorption, and provided basis for quantitative research of treatment of phenol wastewater by adsorbent.更多还原