【摘要】：石墨烯具有化學穩(wěn)定性好和比表面積大等特點,成為吸附應用方面的研究熱點。而水溶性的殼聚糖季銨鹽呈陽離子,能通過靜電作用吸附廢水中的污染物。因此,本文結合石墨烯和殼聚糖季銨鹽兩者的優(yōu)勢,通過非共價靜電作用制備殼聚糖季銨鹽改性的石墨烯(HACC-RGO),希望提高石墨烯在水溶液中的分散性、穩(wěn)定性,以及賦予石墨烯更好的吸附性能。首先,殼聚糖季銨鹽(HACC)通過靜電作用與氧化石墨烯(GO)結合,然后利用水合肼還原得到HACC改性的石墨烯(HACC-RGO)。采用紅外光譜、X射線衍射和掃描電子顯微鏡對HACC-RGO進行結構和形貌的表征,熱重測試分析改性劑HACC在HACC-RGO中的實際含量,Zeta電位分析儀對比不同改性石墨烯的Zeta電位值,并通過動態(tài)光散射粒徑儀研究HACC-RGO在不同pH值溶劑中的分散性及粒徑大小。結果表明,HACC成功結合到石墨烯表面上并插入石墨烯片層間,HACC-RGO中HACC的含量隨著HACC用量的增大而增加,Zeta電位值也隨之增加,而相應HACC-RGO的粒徑減小。得到的HACC-RGO在pH為2-9的水溶液中均能穩(wěn)定分散。通過循環(huán)伏安法研究HACC-RGO的電化學性能,結果表明HACC-RGO具有較好的導電性。然后,通過紫外可見分光光度法研究HACC-RGO粉末對甲基橙溶液的吸附效果,探討吸附時間、pH、溫度和吸附劑用量等因素對HACC-RGO吸附甲基橙的影響。結果表明,HACC-RGO對甲基橙的吸附率遠高于RGO和HACC對甲基橙的吸附率。HACC-RGO吸附甲基橙8h可以達到平衡狀態(tài),升高溫度有利于對甲基橙的吸附。HACC-RGO對甲基橙的吸附遵從準二級動力學吸附模型,吸附速率主要受顆粒表面擴散速度的影響,吸附過程更符合Freundlich等溫吸附模型,主要為物理吸附。最后,基于HACC-RGO通過超聲分散在乙酸(0.2mol/L)溶液中的特點,通過微流控技術制備HACC-RGO/殼聚糖(CS)小球。采用X射線衍射、三維視頻顯微鏡、熱重分析和掃描電鏡對HACC-RGO/CS小球進行結構和形貌的表征,HACC-RGO/CS小球為規(guī)則的球形,其中改性石墨烯實際含量與理論值接近。研究了HACC-RGO/CS小球和CS小球對甲基橙的吸附效果,結果表明HACC-RGO小球對甲基橙的吸附率為91.89%,在水和2wt%NaOH溶液中對甲基橙的解吸率分別為11.32%和87%。
[Abstract]:Graphene has become a hot research topic in adsorption applications because of its good chemical stability and large specific surface area. The water-soluble chitosan quaternary ammonium salt is cationic and can adsorb pollutants in wastewater by electrostatic action. Therefore, based on the advantages of graphene and chitosan quaternary ammonium salt, graphene modified by chitosan quaternary ammonium salt (HACC-RGO) was prepared by non-covalent electrostatic action in the hope of improving the dispersion and stability of graphene in aqueous solution and giving graphene better adsorption properties. Firstly, chitosan quaternylammonium salt (HACC) binds to graphene oxide (GO) by electrostatic interaction, and then HACC modified graphene (HACC-RGO) is obtained by reduction with hydrazide hydrate. The structure and morphology of HACC-RGO were characterized by infrared spectroscopy, X-ray diffraction and scanning electron microscope. The actual content of modifier HACC in HACC-RGO was measured by thermogravimetric analysis. The Zeta potential values of different modified graphene were compared by Zeta potential analyzer, and the dispersion and particle size of HACC-RGO in different pH solvents were studied by dynamic light scattering particle size meter. The results show that HACC is successfully bonded to graphene surface and inserted into graphene lamella. the content of HACC in HACC-RGO increases with the increase of HACC dosage, and the potential value of Zeta increases, while the particle size of HACC-RGO decreases. The obtained HACC-RGO can be stably dispersed in aqueous solution with pH of 2 鈮，

本文編號：2497475