本文選題：重金屬離子 + 磁性復(fù)合材料　； 參考：《浙江大學(xué)》2017年博士論文

【摘要】：隨著社會(huì)的發(fā)展和工業(yè)化進(jìn)程的加快,水體中的重金屬離子對(duì)生態(tài)的破壞以及對(duì)人類健康的危害越來(lái)越明顯。納米磁性復(fù)合材料因其獨(dú)特的順磁性、良好的生物相容性、穩(wěn)定的化學(xué)性能、較高的吸附能力、容易回收利用等優(yōu)勢(shì),成為目前國(guó)內(nèi)外最具吸引力的吸附材料之一。根據(jù)這類材料的研究進(jìn)展,還有許多問(wèn)題需要我們繼續(xù)深入探討。如:磁性納米復(fù)合材料的單分散性和穩(wěn)定性、選擇性吸附能力、再生和重復(fù)利用性和吸附機(jī)理研究等方面。本文以Fe3O4、CaFe2O4和CoFe2O4納米磁性粒子作為復(fù)合材料的磁性部分進(jìn)行了制備和表征�？紤]到材料的化學(xué)穩(wěn)定性、制備方法的簡(jiǎn)單易控性以及適宜的磁性能,我們選擇CoFe2O4作為復(fù)合材料的磁性成分,SiO2為非磁性成分,設(shè)計(jì)了不同形貌的核殼結(jié)構(gòu)和多孔結(jié)構(gòu)等材料體系。將制得的納米磁性復(fù)合材料有效的應(yīng)用于吸附水中的重金屬離子,研究了吸附動(dòng)力學(xué)、吸附熱力學(xué)、吸附平衡、吸附劑的再生重復(fù)利用等,為此類復(fù)合材料的實(shí)際應(yīng)用奠定了基礎(chǔ)。主要研究?jī)?nèi)容如下:(1)制備了一種功能化的鏈狀核殼磁性納米復(fù)合材料(CoFe2O4@SiO2-NH2)并將其成功應(yīng)用于對(duì)水溶液中重金屬離子(Cu(Ⅱ)、Cd(Ⅱ)和Mn(Ⅱ))的吸附。這種功能化的磁性復(fù)合材料是由無(wú)定形Si02外殼和CoFe2O4磁性核構(gòu)成。具有較高的飽和磁化強(qiáng)度(28.09emu/g),可在磁場(chǎng)作用下快速分離。對(duì)水溶液中的重金屬離子Cu(Ⅱ)、Cd(Ⅱ)和Mn(Ⅱ)的平衡吸附容量分別為170.83、144.95和110.80 mg/g。此外,此磁性復(fù)合材料對(duì)重金屬離子的吸附過(guò)程更符合準(zhǔn)二級(jí)動(dòng)力學(xué)和Langmuir等溫模型,說(shuō)明吸附主要為化學(xué)吸附。由于吸附受pH影響很大,我們利用鹽酸使吸附劑再生,經(jīng)四次循環(huán)使用后利用率仍可達(dá)到85.41%。說(shuō)明此磁性吸附劑可潛在應(yīng)用于重金屬?gòu)U水處理方面。(2)合成了一種氨基改性的超順磁性CoFe2O4@SiO2單分散核殼納米球,并研究了其對(duì)水體中重金屬離子的吸附性能。此納米球由磁性核CoFe2O4(～10 nm)和二氧化硅層(～35 nm)以及氨基功能化層構(gòu)成。這種單分散的納米球由于大的比表面積,能夠嫁接較多的氨基基團(tuán),提高對(duì)重金屬離子(Cu(Ⅱ)、Cd(Ⅱ)和Pb(Ⅱ))的吸附能力。納米球的吸附過(guò)程可以很好的用Langmuir模型描述,通過(guò)線性擬合得出對(duì)Cu(Ⅱ)的單分子最大吸附容量為410.72 mg/g。吸附動(dòng)力學(xué)符合準(zhǔn)二級(jí)動(dòng)力學(xué)模型,說(shuō)明吸附為化學(xué)吸附。吸附熱力學(xué)分析表明吸附過(guò)程為自發(fā)的并且吸熱的。經(jīng)酸處理后得到再生吸附劑,重復(fù)使用5次后,吸附劑對(duì)Cu(Ⅱ)、Cd(Ⅱ)和Pb(Ⅱ)的去除率影響不大,并且仍可保持結(jié)構(gòu)和磁性的穩(wěn)定性。因此,這種單分散的超順磁性納米球能夠高效的去除水溶液中的重金屬離子。(3)制備了 一種多孔磁性納米復(fù)合材料CoFe2O4/SiO2,氨基功能化后,用于高效去除水溶液中重金屬離子。這種復(fù)合材料的制備方法簡(jiǎn)單易控,且產(chǎn)率較大,利于產(chǎn)業(yè)化應(yīng)用。制備的多孔CoFe2O4/SiO2的比表面積為167.51 m2/g�？紤]到實(shí)際廢水中共同存在多種重金屬離子,我們研究了材料在單離子和混合離子溶液中對(duì)重金屬離子Cu(Ⅱ)、Mn(Ⅱ)、Cd(Ⅱ)和Pb(Ⅱ)的吸附。結(jié)果表明此吸附劑對(duì)重金屬離子的吸附能力不受其他競(jìng)爭(zhēng)離子的影響,都表現(xiàn)出較大的吸附容量和較高的去除率(90%)。吸附機(jī)理通過(guò)Langmuir吸附等溫線模型、準(zhǔn)二級(jí)吸附動(dòng)力學(xué)模型進(jìn)行線性擬合以及吸附熱力學(xué)分析。結(jié)果表明,這種功能化的多孔磁性復(fù)合材料的優(yōu)良吸附性能歸因于強(qiáng)的表面絡(luò)合作用和其特殊的化學(xué)結(jié)構(gòu)。
[Abstract]:With the development of society and the accelerated process of industrialization, the destruction of heavy metal ions in the water body and the harm to human health are becoming more and more obvious. Nano magnetic composite material has become the present because of its unique paramagnetic, good biocompatibility, stable chemical properties, high adsorption capacity and easy recovery and utilization. One of the most attractive adsorption materials at home and abroad. According to the research progress of this kind of materials, many problems need to be further discussed. For example, the monodispersity and stability, selective adsorption capacity, regeneration and reutilization and adsorption mechanism of magnetic nanocomposites are studied in this paper, Fe3O4, CaFe2O4 and CoFe2O4 nanoscale. Magnetic particles of rice are prepared and characterized as the magnetic parts of the composites. Considering the chemical stability of the materials, the simple controllability and the suitable magnetic properties of the preparation methods, we choose CoFe2O4 as the magnetic component of the composite and the non magnetic component of SiO2, and designs the materials with different morphologies, such as the shell structure and the porous structure. The nano magnetic composites are effectively applied to the heavy metal ions in the adsorbed water. The adsorption kinetics, adsorption thermodynamics, adsorption equilibrium and reutilization of adsorbents have been studied. The main research contents are as follows: (1) a functional chain core shell is prepared. Magnetic Nanocomposites (CoFe2O4@SiO2-NH2) have been successfully applied to the adsorption of heavy metal ions (Cu (II), Cd (II) and Mn (II)) in aqueous solution. This functional magnetic composite is composed of amorphous Si02 shell and CoFe2O4 magnetic core. It has high saturation magnetization (28.09emu/g) and can be separated rapidly under the action of magnetic field. The equilibrium adsorption capacity of heavy metal ions Cu (II), Cd (II) and Mn (II) in aqueous solution is 170.83144.95 and 110.80 mg/g. respectively. The adsorption process of the magnetic composite on heavy metal ions is more consistent with the quasi two order kinetics and Langmuir isothermal model, indicating that the adsorption is mainly chemisorption. Because adsorption is greatly influenced by pH, we have a great effect on adsorption. Using hydrochloric acid to regenerate the adsorbent, the utilization rate of the adsorbent can still reach 85.41%. after four cycles. It shows that the magnetic adsorbent can be applied to the treatment of heavy metal wastewater. (2) a kind of amino modified superparamagnetic CoFe2O4@SiO2 monodisperse nuclear shell nanospheres have been synthesized, and the adsorption properties of heavy metal ions in water are studied. The rice ball is made up of magnetic core CoFe2O4 (~ 10 nm) and silica layer (35 nm) and amino functional layer. This monodisperse nano ball can grafted more amino groups and improve the adsorption capacity of heavy metal ions (Cu (II), Cd (II) and Pb (II)) by large specific surface area. The adsorption process of nanospheres can be well used in Langmuir The model describes the maximum adsorption capacity of the single molecule of Cu (410.72 mg/g.) by linear fitting. The adsorption kinetics is in accordance with the quasi two class kinetic model, which indicates that the adsorption is chemical adsorption. The adsorption thermodynamics analysis shows that the adsorption process is spontaneous and endothermic. After the acid treatment, the adsorbent is reused for 5 times and the adsorbents are reused for 5 times. The removal rate of Cu (II), Cd (II) and Pb (II) has little effect, and the stability of the structure and magnetic properties can still be maintained. Therefore, the monodisperse superparamagnetic nanospheres can effectively remove heavy metal ions in the aqueous solution. (3) a porous magnetic nano composite material CoFe2O4/SiO2 is prepared. After the amino function is functionalized, it is used to efficiently remove water. The preparation of heavy metal ions in the solution is simple and easy to control, and the yield is large, which is beneficial to the industrial application. The specific surface area of the porous CoFe2O4/SiO2 is 167.51 m2/g., considering the common presence of heavy metal ions in the actual wastewater. We studied the heavy metal ions in the single and mixed ion solutions. The adsorption of Cu (II), Mn (II), Cd (II) and Pb (II) shows that the adsorbability of the adsorbent on heavy metal ions is not affected by other competitive ions, and shows a larger adsorption capacity and higher removal rate (90%). The adsorption mechanism is linear and absorbable by Langmuir adsorption isothermal model and quasi two order adsorption kinetic model. The results show that the excellent adsorption properties of this functionalized porous magnetic composite are attributed to the strong surface complexation and its special chemical structure.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB383.1;O647.3

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