改性PVA-co-PE纳米纤维膜用于重金属吸附的研究
发布时间：2018-10-21 12:25
【摘要】：工业废水中含有大量重金属,因重金属在自然环境中难降解且易在生物体中富集而成为全球关注的环境问题。所以,将污水排放入生态环境之前势必要先去除其中的重金属离子。因此,研究一种高效、可循环利用的吸附材料来用于治理重金属污染是很有必要的。以现已工业化生产的PVA-co-PE纳米纤维为基础材料,制备出PVA-co-PE纳米纤维膜。为提高羟基含量,将纳米微晶纤维素喷涂于膜上。采用1,2,3,4-丁烷四羧酸(BTCA)对该复合纳米纤维膜改性,在膜上接枝能螯合重金属的羧基,通过SEM、ATR、XPS等测试手段来表征BTCA改性后的纳米纤维膜。用BTCA改性膜对Pb(Ⅱ)、Cr(Ⅵ)等金属离子进行吸附,主要探究对Pb(Ⅱ)离子的吸附动力学及热力学、对混合重金属溶液吸附及膜的循环利用性能。与未改性的纳米纤维膜相比,BTCA改性后的膜具有良好吸附Cr(Ⅵ)与Pb(Ⅱ)的能力,特别是BTCA改性后再经NaHCO_3处理,饱和吸附量和去除率大大增加。未经NaHCO_3处理的BTCA改性纳米纤维膜对Pb(Ⅱ)的最大吸附量为19.23 mg/g,最大吸附百分比为61.87%。经NaHCO_3处理后的纳米纤维膜对Pb(Ⅱ)的最大吸附量为52.89 mg/g,最大吸附百分比为99.2%。改性纳米纤维膜对Pb(Ⅱ)的吸附动力学符合准二级吸附模型,即化学吸附,同时经NaHCO_3处理过的膜的吸附符合Freundlich吸附等温线模型,而未处理的膜的吸附符合Langmuir吸附等温线模型。在混合重金属离子吸附中,BTCA改性纳米纤维膜对Cu(Ⅱ)的吸附量及吸附百分比大幅度增强,而对Cr(Ⅵ)与Pb(Ⅱ)吸附量及吸附百分较单一金属溶液吸附时要低。同时,用NaHCO_3处理后的膜,不仅是单一溶液还是混合溶液,吸附量和吸附百分比较未处理的膜要高很多。经处理后的BTCA改性复合膜在3次吸附-脱附循环中,保持了一定的可循环能力。另外,罗丹宁在Fe~(3+)作用下,在PVA-co-PE纳米纤维膜上进行自聚合,纳米纤维膜表面引入N、O、S等杂原子,从而具有吸附性能,通过SEM、ATR、XPS等测试手段来表征罗丹宁改性后的纳米纤维膜。用罗丹宁改性膜对Pb(Ⅱ)、Hg(Ⅱ)金属离子进行吸附,主要探究对Hg(Ⅱ)的吸附动力学及热力学、对混合金属溶液吸附及膜的循环利用性能。该改性膜对Hg(Ⅱ)有较好的吸附能力,对Hg(Ⅱ)和Pb(Ⅱ)最大吸附量分别为17.26 mg/g,3.834 mg/g,对应的最大吸附百分比为88.51%和7.473%。改性后的膜对Hg(Ⅱ)的吸附动力学符合准二级吸附模型,同时符合Langmuir吸附等温线模型。在混合重金属离子吸附中,Hg(Ⅱ)的存在促进了膜对Pb(Ⅱ)的吸附,吸附百分比增强,Hg(Ⅱ)吸附量下降,但吸附百分比不变,即在混合金属离子条件下,改性膜仍可保持相同的去除能力。另外,经罗丹宁改性后的膜可循环能力一般,但具有优良抗菌性。
[Abstract]:Industrial wastewater contains a large number of heavy metals, which is a global environmental problem because heavy metals are difficult to degrade in the natural environment and easy to be enriched in organisms. Therefore, it is necessary to remove heavy metal ions before sewage is discharged into the ecological environment. Therefore, it is necessary to study a highly efficient and recyclable adsorption material for heavy metal pollution control. PVA-co-PE nanofiber membranes were prepared from PVA-co-PE nanofibers, which have been manufactured in industrial production. In order to increase the hydroxyl content, nano-crystalline cellulose was sprayed on the film. The composite nanofiber membrane was modified by (BTCA), then grafted onto the composite nanofiber membrane to chelate the carboxyl group of heavy metals. The modified nano-fiber membrane was characterized by SEM,ATR,XPS and other methods. Metal ions such as Pb (鈪，
本文编号：2285084
[Abstract]:Industrial wastewater contains a large number of heavy metals, which is a global environmental problem because heavy metals are difficult to degrade in the natural environment and easy to be enriched in organisms. Therefore, it is necessary to remove heavy metal ions before sewage is discharged into the ecological environment. Therefore, it is necessary to study a highly efficient and recyclable adsorption material for heavy metal pollution control. PVA-co-PE nanofiber membranes were prepared from PVA-co-PE nanofibers, which have been manufactured in industrial production. In order to increase the hydroxyl content, nano-crystalline cellulose was sprayed on the film. The composite nanofiber membrane was modified by (BTCA), then grafted onto the composite nanofiber membrane to chelate the carboxyl group of heavy metals. The modified nano-fiber membrane was characterized by SEM,ATR,XPS and other methods. Metal ions such as Pb (鈪，
本文编号：2285084
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