船舶机舱含油废水在膨胀石墨/活性炭复合吸附剂上的吸附研究

为分析吸附技术在船舶机舱含油废水处理中的可行性,本文通过化学活化法,分别选择KOH和酚醛树脂作为活化剂和碳源,在由溶液浸渍法制备膨胀石墨/活性炭复合吸附剂后,进行乳化油在制备试样上的吸附平衡和吸附动力学特性作分析。在25℃下,根据重量法的原理测试了乳化油在吸附剂试样上的吸附动力曲线,并通过拟合Lagergren准一级和准二级动力学曲线,确定吸附速率常数与初始吸附速度。在温度区间20℃~30℃,测试乳化油在试样上的吸附等温线后,比较Langmuir,Freundlich和Tempkin吸附等温方程预测吸附平衡数据的精度,并由Van′t Hoff方程计算了吸附平衡过程的焓变和熵变。结果表明,乳化油在复合吸附剂上发生物理吸附且在常温下就可自发进行,研究乳化油在复合吸附剂上的吸附动力学特性和吸附平衡可分别选用Lagergren准二级吸附速率模型和Tempkin吸附等温方程。膨胀石墨/活性炭复合吸附剂用于船舶机舱含油废水的处理具有良好的前景。

Study of adsorption of ship's bilge oily water on expanded graphite/activated carbon composite adsorbents

In order to develop an adsorbent suitable for the treatment of ship's bilge oily wastewater,analysis of adsorption equilibrium and adsorption kinetics of the emulsified oil was respectively carried out on the composite adsorbent of the expanded graphite/activated carbon prepared via impregnation method by employing KOH as activator and phenolic resin as carbon source.Firstly,as per the principle of the gravimetric method,the adsorption kinetics curve of the emulsified oil on the adsorbent sample was measured at 298.15 K,and the adsorption rate constant and the initial adsorption rate were calculated by the Lagergren quasi-first-order and quasi-second-order kinetic curves.Secondly,adsorption isotherms ofthe emulsified oil on the sample was measured at temperature range of 293.15~308.15 K,accuracies of Langmuir,Freundlich and Temkin adsorption models in predicting adsorption equilibrium dada were compared,and the variation of enthalpy and entropy in the adsorption process were then determined by the plot of Van*t Hoff equation.It shows that the Lagergren quasisecondary adsorption rate model is suitable for describing the kinetic characteristic of adsorption of emulsified oil on the composite adsorbent,the as-prepared composite adsorbent has a considerable amount on the adsorption of the emulsified oil,and Tempkin adsorption model has the highest accuracy in prediction.Results also reveal that the adsorption of the emulsified oil on the composite adsorbent is a physical one which can take place at ambient temperature.It suggests that the composite adsorbent prepared by expanded graphite and activated carbon has a good prospect for the treatment of ship's bilge oily wastewater.