磁性果汁残渣作为新型吸附剂处理重金属及染料废水的研究

发布时间：2018-02-22 11:11

本文关键词： 磁性果汁残渣吸附重金属染料　出处：《山东农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文以农产品废弃物-果汁残渣作(JR)为基本的吸附材料,与具有磁性的纳米Fe3O4通过三聚磷酸钠的交联作用合成了新型具有磁性的果汁残渣吸附剂(MJR),并通过FT-IR、BET、XRD、Zeta电位、磁化强度对其进行了表征。以常见的重金属Pb(II)和阴离子染料孔雀绿(MG)作为目标污染物,通过批量实验,研究了p H、吸附剂量和接触时间对吸附过程的影响,探究了最佳吸附条件。利用了准二次动力学模型、内部扩散动力学模型、Langmuir等温线模型、Freundlich等温线模型、D-R等温线模型,对批量实验得到的实验数据进行模型的拟合,揭示出吸附作用机理。并通过磁性实验,实现吸附剂与吸附质的快速分离。本文得出以下几点结论:(1)FT-IR红外分析表明,JR的3250 cm-1波峰转移到MJR的3370 cm-1处,且波峰的强度增大,MJR的1055 cm-1处波峰也显著增强,说明通过磁性改良后不仅没减少JR表面官能团,反而增强了其官能团,有助于增强吸附能力。BET分析测得JR的比表面积为4.33 m2/g,MJR的比表面积为1.88 m2/g,说明通过磁性Fe3O4改性后,由于Fe3O4粒子填充了JR的部分孔径,导致其比表面积的降低。XRD分析测定制备的磁性氧化铁的六个特征峰(2θ=30.18°、35.65°、43.36°、53.62°、57.01°和62.83°)分别为Fe3O4的六个反射平面,证明了氧化铁成分为磁铁矿(Fe3O4)。Zeta电位表明,在同一pH条件下,MJR表面的负电性比JR的负电性更强,暗示着MJR对带正电的阳离子有较强的静电吸引作用。磁化强度分析表明,通过磁滞曲线可以得出Fe3O4和MJR的饱和磁化强度分别为61.6和20.5 emu/g,揭示了果汁残渣已经被成功的磁化,具有较高的顺磁性且磁感应性较强,且足以通过外加磁场使其快速分离。(2)通过批量实验,得出MJR吸附Pb(II)和MG的最佳实验条件分别为122.5 min、5.06 g/L、6.10和66.69 min、5.14 g/L、6.06。(3)通过模型拟合表明,MJR吸附Pb(II)过程既符合Langmuir等温线模型,又符合Freundich等温线模型。MJR吸附MG过程符合Langmuir等温线模型,但不符合Freundich等温线模型。MJR吸附Pb(II)和MG的最大比吸附量分别为48.74、106.24 mg/g。(4)进行了磁性分离实验,在外加磁场的条件下,MJR实现固液分离只需要30秒,大大缩短的固液分离时间。
[Abstract]:In this paper, a new magnetic adsorbent, MJRN, was synthesized by the cross-linking reaction of sodium tripolyphosphate with the magnetic nanometer Fe3O4 using the residue of agricultural products and fruit juice as the basic adsorption material, and the Zeta potential of the adsorbent was obtained by FT-IRN BET-XRDU. It was characterized by magnetization. The effects of pH, amount of adsorbent and contact time on the adsorption process were studied by batch experiments with the common heavy metal PbCII) and the anionic dye malachite green (MG) as the target pollutants. The optimal adsorption conditions were investigated. The quasi quadratic kinetic model and the internal diffusion kinetic model were used to simulate the Freundlich isotherm model and the D-R isotherm model. The mechanism of adsorption was revealed, and the rapid separation of adsorbent and adsorbate was realized by magnetic experiment. The following conclusions were obtained in this paper: the 3250 cm-1 peak of JR was transferred to 3370 cm-1 of MJR by FT-IR analysis. The intensity of the wave peak increased significantly at 1055 cm-1 of MJR, which indicated that the magnetic modification not only did not decrease the surface functional group of Jr, but also enhanced its functional group. The specific surface area of JR is 4.33 m ~ (-2) / g ~ (-1) m ~ (2 / g), which is 1.88 m ~ (2 / g) by magnetic Fe3O4 modification, which indicates that, after modification by magnetic Fe3O4, the partial pore size of Jr is filled with Fe3O4 particles, and the specific surface area of JR is 4.33 m ~ (-2) / g ~ (-1). The results show that the six characteristic peaks of magnetic ferric oxide prepared by XRD analysis are the six reflection planes of Fe3O4, respectively. The results show that the composition of ferric oxide is magnetite Fe _ 3O _ 4 路Zeta potential, which indicates that the six characteristic peaks of magnetic iron oxide are 36.18 掳~ 35.65 掳/ 43.36 掳/ 53.62 掳/ 57.01 掳and 62.83 掳, respectively, and the results show that the magnetic ferric oxide is composed of Fe _ 3O _ 4, Fe _ 3O _ 4 and Fe _ 3O _ 4. At the same pH, the negative electric property of MJR surface is stronger than that of JR, suggesting that MJR has a strong electrostatic attraction to positive cations. The saturation magnetization of Fe3O4 and MJR are 61.6 and 20.5emu / g, respectively. The results show that the juice residue has been magnetized successfully and has high paramagnetism and strong magnetic induction. The optimum experimental conditions for MJR adsorption of PBII) and MG were 122.5 min / L 6.10 and 66.69 min / L 5.14 g / L ~ (6.06.3) respectively. The results of model fitting showed that the process of PbIIs adsorption was in accordance with the Langmuir isotherm model. Freundich isotherm model. MJR adsorption process accords with Langmuir isotherm model, but not with Freundich isotherm model. The maximum specific adsorption capacity of MG and MJR isotherm model is 48.74mg / g 路g 路mg. Under the condition of external magnetic field, it takes only 30 seconds to realize solid-liquid separation by MJR, which greatly shortens the time of solid-liquid separation.
【学位授予单位】：山东农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X791

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