Abstract

Chitosan is a natural polymer that has proved its uses in many research areas because of its wide range of properties specially its adsorption properties can purify water by sticking metallic ions to its surface. In the present study local bio waste of shrimp shells was converted into chitin and then to chitosan. Chitosan was extracted by the combination of different processes. Shrimp shells were dried, soaked in 4% NaOH solution for 20 h, soaked it in 4% HCl solution for 10 h, again treated with NaOH but with 2% concentration for 24 h, soaked in 1% HCl for 12 h and washed with distilled water. Treatment with NaOH deprotienize the shrimp shell and HCl is supposed to demineralize the sample. Deprotienized and demineralized samples were then decolorized with 1% KMnO₄ for 1 h. Sample was then treated by it 1% oxalic acid for 3 h. Decolorized sample, called chitin is brilliant white in color was soaked in 65% NaOH solution for around 70 h and the chitosan was extracted. Graphene oxide was also synthesized separately. The chitosan-graphene oxide hydrogel was prepared by socializing graphene oxide sheets and chitosan chains. The FTIR results showed the characteristic peaks of chitosan while UV-Vis spectroscopy of graphene oxide also confirmed the formation of graphene. The hydrogel obtained from CS-GO was also characterized through XRD and FTIR spectroscopy. Different samples of wastewater from industries, as well as self-prepared sample of copper sulphate, zinc chloride, and nickel sulphate were treated with the CS-GO hydrogel to reduce the contaminations in water. The hydrogel was simply poured in water and water was shaken, it was found that all the colored solutions were either became transparent or their transparency was increased due to the treatment with CS-GO hydrogel. It proves that the CS-GO successfully reduced the concentration of contaminants from waste water and a visible change of color was seen in the samples. The UV-VIS spectroscopies were also performed on all samples and a remarkable increase in transmittance was observed in all samples treated with CS-GO hydrogel.

中文翻译：

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壳聚糖和氧化石墨烯的合成及表征，形成用于去除重金属离子的纳米复合水凝胶

摘要

壳聚糖是一种天然聚合物，由于其广泛的性能而已在许多研究领域得到证明，特别是其吸附性能可通过将金属离子粘附在其表面上来净化水。在本研究中，虾壳的当地生物废物被转化为甲壳素，然后转化为壳聚糖。壳聚糖是通过不同工艺组合提取的。将虾壳干燥，在4％NaOH溶液中浸泡20 h，在4％HCl溶液中浸泡10 h，再次用NaOH处理，但以2％的浓度浸泡24 h，在1％HCl中浸泡12 h，然后用蒸馏水。用NaOH处理会使虾壳脱蛋白，而用HCl处理会使样品脱矿质。然后用1％KMnO _4对去蛋白和去矿物质的样品进行脱色1小时。然后将样品用1％草酸处理3小时。将脱色的样品称为甲壳质，其颜色为亮白色，将其浸入65％NaOH溶液中约70 h，然后提取壳聚糖。氧化石墨烯也被单独合成。壳聚糖-氧化石墨烯水凝胶是通过社交化氧化石墨烯片和壳聚糖链而制备的。FTIR结果显示了壳聚糖的特征峰，而氧化石墨烯的UV-Vis光谱也证实了石墨烯的形成。还通过XRD和FTIR光谱表征了从CS-GO获得的水凝胶。CS-GO水凝胶处理了来自工业废水的不同样品，以及硫酸铜，氯化锌和硫酸镍的自备样品，以减少水中的污染。只需将水凝胶倒入水中，然后摇动水，发现所有有色溶液要么变得透明，要么由于使用CS-GO水凝胶处理而增加了透明度。证明CS-GO成功降低了废水中的污染物浓度，并在样品中看到了明显的颜色变化。还对所有样品进行了UV-VIS光谱分析，并且在所有使用CS-GO水凝胶处理的样品中均观察到透射率显着增加。