功能化纳米复合材料Fe3O4@SiO2-3-氨丙基三甲氧基硅烷的制备及其对Pb(II)的吸附

牛乙涛; 包国庆; 吴纯鑫; 赵德明

doi:10.13801/j.cnki.fhclxb.20220905.001

功能化纳米复合材料Fe₃O₄@SiO₂-3-氨丙基三甲氧基硅烷的制备及其对Pb(II)的吸附

doi: 10.13801/j.cnki.fhclxb.20220905.001

浙江工业大学　化学工程学院，杭州 310014

基金项目: 浙江省自然科学基金(LY19B070006)；浙江省基础公益研究计划项目(LGF20B070003)

详细信息

通讯作者:
赵德明，博士，副教授，硕士生导师，研究方向为功能材料、环境化工　E-mail: dmzhao@zjut.edu.cn

中图分类号: X78；TQ138.1；TB332
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出版历程
- 收稿日期: 2022-07-12
- 修回日期: 2022-08-14
- 录用日期: 2022-08-26
- 网络出版日期: 2022-09-06
- 刊出日期: 2023-06-15

Preparation of functionalized nanocomposites Fe₃O₄@SiO₂-3-aminopropyltrimethoxysilane and its adsorption to Pb(Ⅱ)

School of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China

Funds: Natural Science Foundation of Zhejiang Province (LY19B070006); Basic Public Welfare Research Program of Zhejiang Province (LGF20B070003)

摘要

摘要: 为解决磁性纳米Fe₃O₄颗粒易腐蚀、团聚等问题，对其进行功能化修饰改进。在超声波辐照下以FeCl₃和FeSO₄为原料，氨水为沉淀剂，然后加入正硅酸乙酯(TEOS)和3-氨丙基三甲氧基硅烷(APTMS)进行功能化修饰，制备得到SiO₂包覆的氨基功能化纳米复合材料Fe₃O₄@SiO₂-APTMS，并采用TEM、FTIR、VSM、TGA、低温氮吸附、XRD等对其进行表征测试，证实了超声波辐照下制备的复合材料具有磁响应强度强、耐酸碱性强、分散性高、比表面积大、粒径小等特点，同时探究了纳米复合材料对Pb(Ⅱ)的吸附性能。结果表明：溶液初始pH值为5.86，吸附剂投加量为1.0~1.5 g·L⁻¹时Pb(Ⅱ)吸附效果较好；Langmuir模型适合模拟该等温吸附过程，吉布斯自由能变∆G⁰<0，吸附过程是一个自发过程；准二级动力学可以较好地描述Pb(Ⅱ)在复合材料上的吸附行为，准二级动力学常数k₂=0.0401 g·mg⁻¹·min⁻¹，达到吸附平衡时的吸附量q_e=80.041 mg·g⁻¹；推测得到吸附机制主要为离子交换和络合吸附。
- 超声波 /
- 磁性纳米复合材料 /
- 络合吸附 /
- 吸附动力学 /
- 铅离子
Abstract: In order to solve the indefects that magnetic nano-Fe₃O₄ particles were corroded and agglomerated easily, functional modification was carried out. FeCl₃ and FeSO₄ were used as raw materials and ammonia as preci-pitant in the presence of ultrasonic irradiation, then functionalized by ethyl orthosilicate (TEOS) and 3-aminopropyltrimethoxysilane (APTMS) to prepare SiO₂-coated amino-functional nanocomposites Fe₃O₄@SiO₂-APTMS. The magnetic nanocomposites were characterized by TEM, FTIR, VSM, TGA, low temperature nitrogen adsorption and XRD, etc. The characterized results show that the magnetic nanocomposites prepared by ultrasonic strengthening method have the characteristics of strong magnetic response, strong acid and alkali resistance, high dispersion, large specific surface area and small particle size.Meanwhile, the adsorption effects of magnetic nanocomposites for Pb(Ⅱ) were investigated. The results show that the initial pH value of the solution and the dosage of adsorbent have greatest effects on the adsorption effect of Pb(Ⅱ) with the initial pH value of the solution 5.86 and the dosage of adsorbent 1.0-1.5 g·L⁻¹. The Langmuir model is suitable for simulating the isothermal adsorption process, and the adsorption process is a spontaneous process when Gibbs free energy change ∆G⁰<0. The adsorption behavior of Pb(Ⅱ) can be well described by quasi-second-order kinetics on the composites, Quasi-second-order kinetic constant k₂=0.0401 g·mg⁻¹·min⁻¹, equilibrium adsorption capacity q_e=80.041 mg·g⁻¹; it is speculated that the adsorption mechanism is mainly complex adsorption and ion exchange.
- ultrasonic /
- magnetic nanocomposites /
- complex adsorption /
- adsorption kinetics /
- lead ions

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图 1 纳米复合材料Fe₃O₄@SiO₂-3-氨丙基-三甲氧基硅烷(APTMS)的合成

Figure 1. Fe₃O₄@SiO₂-3-aminopropyltrimethoxysilane (APTMS) synthesis diagram of nanocomposites

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图 2 不同方法制备的纳米复合材料Fe₃O₄@SiO₂、Fe₃O₄@SiO₂-APTMS的TEM图像

Figure 2. TEM images of Fe₃O₄@SiO₂, Fe₃O₄@SiO₂-APTMS nanocomposites prepared by different methods

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图 3 不同方法制备的纳米复合材料的XRD图谱 (a)、FTIR图谱 (b) 及TG (c) 和DTG曲线 (d)

Figure 3. XRD pattern (a), FTIR spectra (b) and TG curves (c) and DTG curves (d) of nanocomposites prepared by different methods

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图 4 Fe₃O₄@SiO₂、无超声波和有超声波下制备的Fe₃O₄@SiO₂-APTMS的磁滞回线

Figure 4. Magnetic hysteresis loops of Fe₃O₄@SiO₂ and Fe₃O₄@SiO₂-APTMS synthesized in the absence of ultrasound and in the presence of ultrasound

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图 5 Fe₃O₄@SiO₂、无超声波和有超声波下制备的Fe₃O₄@SiO₂-APTMS对Pb(Ⅱ)吸附效果的影响

Figure 5. Effects of Fe₃O₄@SiO₂, Fe₃O₄@SiO₂-APTMS prepared without ultrasound and with ultrasound on the adsorption of Pb(Ⅱ)

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图 6 Fe₃O₄@SiO₂-APTMS的N₂吸附脱附等温线及孔径分布图

Figure 6. N₂ adsorption-desorption isotherm and pore size distribution of Fe₃O₄@SiO₂-APTMS

STP—Standard temperature and pressure

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图 7 吸附剂投加量、溶液初始pH值、竞争性离子和温度对Fe₃O₄@SiO₂-APTMS吸附Pb(Ⅱ)的影响

Figure 7. Effects of adsorbent dosage, initial pH value of solution, competitive ions and temperature on the adsorption of Pb (Ⅱ) by Fe₃O₄@SiO₂-APTMS

q_e—Equilibrium adsorption capacity

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图 8 不同Pb(Ⅱ)浓度下lnK₀对1/T图

Figure 8. lnK₀ plots of 1/T at different Pb(Ⅱ) concentrations

K₀—Thermodynamic equilibrium constant; R²—Linear correlation coefficient

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图 9 Fe₃O₄@SiO₂-APTMS对Pb(Ⅱ)的吸附量随时间变化图和动力学模型拟合

Figure 9. Fe₃O₄@SiO₂-APTMS adsorption Pb (Ⅱ) adsorption capacity curve with time and kinetics model fitting

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图 10 Pb(Ⅱ)吸附等温线及Pb(Ⅱ)等温吸附模型拟合线

Figure 10. Pb(Ⅱ) adsorption isotherm and Pb(Ⅱ) isothermal adsorption model fitting curves

C_e—Concentration of Pb(Ⅱ) in solution at adsorption equilibrium

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图 11 重复使用次数对Fe₃O₄@SiO₂-APTMS吸附Pb(Ⅱ)的影响

Figure 11. Effect of reuse times on Fe₃O₄@SiO₂-APTMS adsorption of Pb(Ⅱ)

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图 12 Fe₃O₄@SiO₂-APTMS复合材料吸附Pb(Ⅱ)前后的FTIR图谱

Figure 12. FTIR spectra of Fe₃O₄@SiO₂-APTMS before and after adsorption of Pb (Ⅱ)

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图 13 纳米复合材料 Fe₃O₄@SiO₂-APTMS吸附 Pb(Ⅱ)的机制图

Figure 13. Mechanism diagram of adsorption of Pb(Ⅱ) by nanocomposite Fe₃O₄@SiO₂-APTMS

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图 14 Fe₃O₄@SiO₂-APTMS吸附Pb(Ⅱ)、Cu(Ⅱ)和Ni(Ⅱ)的混合溶液各离子吸附量随时间的变化

Figure 14. Variation of ion adsorption capacity with time in mixed solution of Pb (Ⅱ), Cu (Ⅱ) and Ni (Ⅱ) adsorbed by Fe₃O₄@SiO₂-APTMS

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表 1 不同吸附剂对Pb(Ⅱ)的吸附效果比较

Table 1. Comparison of adsorption effects of different adsorbents for Pb (Ⅱ)

Adsorbent	Saturated adsorption capacity q_m/(mg·g⁻¹)	Ref.
Fe₃O₄-SiO₂-NH-COOH	208.70	[24]
NaOH modified zeolite	260.00	[25]
Fe₃O₄@PAMAM	345.10	[26]
Fe₃O₄@SiO₂-APTMS	384.76	This study
Note: PAMAM—Polyamide-amine dendritic polymer.

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表 2 Fe₃O₄@SiO₂-APTMS吸附Pb(Ⅱ)热力学常数

Table 2. Thermodynamic constants of Pb(Ⅱ) adsorbed by Fe₃O₄@SiO₂-APTMS

C₀/(mg·L⁻¹)	ΔG⁰/(kJ·mol⁻¹)				ΔH⁰/(kJ·mol⁻¹)	ΔS⁰/(J·mol⁻¹·K⁻¹)
C₀/(mg·L⁻¹)	283 K	293 K	303 K	313 K	ΔH⁰/(kJ·mol⁻¹)	ΔS⁰/(J·mol⁻¹·K⁻¹)
50	−3.555	−4.373	−4.827	−5.292	12.513	57.125
100	−3.746	−4.067	−4.609	−5.115	9.391	46.227
150	−3.767	−4.313	−4.871	−5.423	11.871	55.271
Notes: C₀—Initial concentration of Pb (Ⅱ) solution; ∆G⁰—Gibbs free energy change; ∆H⁰—Enthalpy change; ∆S⁰—Entropy change.

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表 3 Fe₃O₄@SiO₂-APTMS对Pb(Ⅱ)吸附动力学方程拟合结果

Table 3. Fitting results of Pb (Ⅱ) adsorption kinetic equation by Fe₃O₄@SiO₂-APTMS

Quasi-first order kinetics				Quasi-second-order kinetics				Internal diffusion equation
k₁	q_e,_cal	q_e,_exp	R²	k₂	q_e,_cal	q_e,_exp	R²	k_p	C	R²
0.0165	2.714	80.041	0.789	0.0401	79.99	80.041	0.999	k_p1=2.0639	69.675	0.952
								k_p2=0.0616	79.223	0.969
								k_p3=0.0092	79.823	0.980
Notes: q_e,_cal—Theoretical saturated adsorption capacity; q_e,_exp—Experimental saturated adsorption capacity; k₁—Quasi-first-order kinetic constant; k₂—Quasi-second-order kinetic constant; C—Constant related to thickness and boundary layer.

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表 4 Fe₃O₄@SiO₂-APTMS对Pb(Ⅱ)的吸附等温线拟合结果

Table 4. Adsorption isotherm fitting results of Pb(Ⅱ) by Fe₃O₄@SiO₂-APTMS

T/K	Langmuir				Freundlich			Temkin
T/K	K_L	q_m	R_L	R²	K_F	R²	K_t	B_l	R²
308	0.0387	401.606	0.0252-0.615	0.991	47.83	0.905	0.534	74.27	0.989
298	0.0323	390.625	0.0312-0.570	0.993	39.57	0.916	0.373	79.25	0.988
288	0.0311	366.300	0.0300-0.602	0.995	33.41	0.946	0.299	81.02	0.977
Notes: K_L—Langmuir adsorption coefficient (L·mg⁻¹); K_F—Freundlich adsorption coefficient (mg^1−(1/n)·L^1/n·g⁻¹); K_t, B_l—Temkin adsorption isotherm constant; q_m—Saturated adsorption capacity (mg·g⁻¹); R_L—Separation constant; R²—linear correlation coefficient.

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表 5 复合材料耐酸碱腐蚀性研究

Table 5. Study on acid and alkali corrosion resistance of compound materials

Condition	Solution	Fe₃O₄@SiO₂	Fe₃O₄@SiO₂-APTMS
Condition	Solution	Fe/(mg·L⁻¹)	Fe/(mg·L⁻¹)	TOC/(mg·L⁻¹)
298 K, soak, 24 h	Water	0.135	0.015	0.025
	0.1 mol·L⁻¹ HCl	3.598	0.206	3.420
	1 mol·L⁻¹ HCl	25.542	2.729	8.866
	0.1 mol·L⁻¹ NaOH	0.137	0.149	6.712
	1 mol·L⁻¹ NaOH	0.276	0.186	8.106
313 K, stirring, 72 h	Water	0.138	0.016	0.027
	1 mol·L⁻¹ HCl	24.842	2.629	8.886
	1 mol·L⁻¹ NaOH	0.281	0.189	8.126
313 K, stirring, 96 h	Water	0.140	0.017	0.029
	1 mol·L⁻¹ HCl	25.552	2.749	8.916
	1 mol·L⁻¹ NaOH	0.296	0.191	8.173
Note: TOC—Total organic carbon.

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