木质纤维素/纳米蒙脱土复合材料对废水中Cu(II)的吸附及解吸

Adsorption and desorption of Cu (II) in wastewater by lignocellulose/ nano-montmorillonite composites

  • 摘要: 采用木质纤维素(LNC)与纳米蒙脱土(nano-MMT)插层复合制备出的LNC/nano-MMT复合材料作为吸附剂, 进行了模拟含铜废水中Cu (II)的吸附和解吸实验。通过静态吸附实验, 研究了含Cu (II)溶液的初始浓度、 pH值、 吸附温度和吸附时间对溶液中Cu (II)吸附效果的影响。结果表明: 最佳的吸附条件是Cu (II) 溶液初始浓度0.03 mol·L-1, pH值4.9, 吸附温度50 ℃, 吸附时间60 min 时, 吸附容量达到最大值322.56 mg·g-1。准二级动力学模型能很好地描述其吸附过程, 吸附等温线符合Langmuir模型。使用HNO3对LNC/nano-MMT复合材料进行解吸再生实验。结果表明: 以0.1 mol·L-1 的HNO3作为解吸剂, 解吸温度 40 ℃, 超声波解吸时间30 min时最大解吸量可达到 283.15 mg·g-1。结合XRD、 SEM和FTIR分析LNC/nano-MMT复合材料的吸附机制。吸附/解吸循环实验研究表明:LNC/nano-MMT复合材料重复使用4次时吸附量仍较高, 是一种优良的可循环利用的高效吸附剂。

     

    Abstract: The lignocellulose/nano-montmorillonite (LNC/nano-MMT) composites prepared were taken as the adsorbent to research the adsorption and desorption properties of Cu (II) from copper-contained wastewater, which were synthesized by the chemical intercalation process of LNC and nano-MMT. The affecting parameters on the Cu (II) adsorption capacity by changing initial concentration of Cu (II) ion, solution pH value, adsorption temperature and adsorption time were studied in detail. The results show that the equilibrium adsorption capacity could be reached 322.56 mg·g-1 under the optimal condition, 0.03 mol·L-1 initial concentration of Cu (II) ion, 4.9 of the solution pH value, 50 ℃ of the adsorption temperature and 60 min of the adsorption time. The pseudo-second-order kinetic model could well describe the whole adsorption process, and the isotherm adsorption equilibrium is conformed to the Langmuir model. HNO3 was used to perform desorption and regeneration experiments of LNC/nano-MMT composites. The results show that HNO3 concentration 0.1 mol·L-1, desorption temperature 40 ℃ and desorption time 30 min treated by ultrasonic wave, the satisfactory effect of desorption capacity is 283.15 mg·g-1. The adsorption mechanism of LNC/nano-MMT was discussed in combination with the results of XRD, SEM and FTIR. The adsorption/desorption experiment displays that the adsorption capacity of LNC/nano-MMT is ideal for four cycles, so LNC/nano-MMT is confirmed as a high efficient adsorbent for recycling.

     

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