油页岩灰基磁性分子筛的制备及其对亚甲基蓝的吸附性能

doi:10.11901/1005.3093.2024.290

油页岩灰基磁性分子筛的制备及其对亚甲基蓝的吸附性能

段玉¹, 王倩^,¹, 刘宏臣¹, 车远军¹, 石磊¹, 白慧娟^,²

1.西安工程大学环境与化学工程学院西安 710048

2.中国科学院过程工程研究所中国科学院绿色过程与工程重点实验室北京 100190

Methylene Blue Adsorption Performance of Magnetic Zeolite Prepared from Oil Shale Ash

DUAN Yu¹, WANG Qian^,¹, LIU Hongchen¹, CHE Yuanjun¹, SHI Lei¹, BAI Huijuan^,²

1.School of Environmental and Chemical Engineering, Xi'an Polytechnic University, Xi'an 710048, China

2.CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China

通讯作者: 王倩，shangjinzhe@163.com，研究方向为油页岩结构研究及其高值利用；白慧娟，副研究员，huijuanbai@ipe.edu.cn，研究方向为多功能材料设计及应用

责任编辑: 吴岩

收稿日期: 2024-06-27 修回日期: 2024-09-18

基金资助:

国家自然科学基金(22008187)
国家自然科学基金(22208256)
国家自然科学基金(22308269)

Corresponding authors: WANG Qian, Tel: 13263280805, E-mail:shangjinzhe@163.com;BAI Huijuan, Tel: 18811036008, E-mail:huijuanbai@ipe.edu.cn

Received: 2024-06-27 Revised: 2024-09-18

Fund supported:

National Natural Science Foundation of China(22008187)
National Natural Science Foundation of China(22208256)
National Natural Science Foundation of China(22308269)

作者简介 About authors

段玉，女，2000年生，硕士生

摘要

以油页岩灰为原料用碱熔水热法制备了Fe₃O₄@NaX型磁性分子筛并用于吸附亚甲基蓝(MB)，研究了在不同条件下这种分子筛对MB的吸附性能并揭示其机理。结果表明：在2.0% Fe₃O₄@NaX (质量分数)型磁性分子筛用量为1 g/L、溶液的初始pH值为5.7、MB溶液的初始浓度为50 mg/L、吸附温度为25 ℃的条件下，分子筛对MB吸附60 min，MB的吸附率和平衡吸附量分别为96.98%和45.19 mg/g。这种分子筛在外磁场作用下能使染料溶液快速分离，且其再生重复使用的性能较好。Fe₃O₄@NaX型分子筛对MB的吸附遵循拟二级动力学和Langmuir等温线模型，是一个自发和放热的熵减过程。静电引力、氢键和孔隙扩散是吸附的主要推动力。

关键词： 材料合成与加工工艺; 磁性分子筛; 碱熔水热法; 吸附; 油页岩灰; 亚甲基蓝

Abstract

Fe₃O₄@NaX magnetic zeolite was prepared via alkaline fusion hydrothermal method with Fe₃O₄ particles and Beipiao oil shale ash as raw material, aiming to making magnetic absorbent substance for absorbing methylene blue (MB) from waste water. The adsorption performance of the magnetic zeolite for MB were studied in various processing conditions, and the adsorption mechanism was revealed. The results show that the removal efficiency and equilibrium adsorption capacity of 2.0% Fe₃O₄@NaX (mass fraction) zeolite for MB were 96.98% and 45.19 mg/g, respectively, in the following adsorption conditions: zeolite dosage of 1 g/L, initial pH of 5.7 of the solution, initial MB concentration of 50 mg/L, adsorption temperature of 25 °C and adsorption time of 60 min. The magnetic zeolite can be separated rapidly from dye solution by an applied external magnetic field, indicating its excellent recyclability. The MB adsorption on the zeolite is a spontaneous and exothermic process of entropy reduction, which follows the pseudo-second-order kinetics and Langmuir isotherm models. The electrostatic attraction, hydrogen bonds and pore diffusion are the main driving forces of the adsorption process.

Keywords： synthesizing and processing technics for materials; magnetic zeolite; alkaline fusion hydrothermal method; adsorption; oil shale ash; methylene blue

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本文引用格式

段玉, 王倩, 刘宏臣, 车远军, 石磊, 白慧娟. 油页岩灰基磁性分子筛的制备及其对亚甲基蓝的吸附性能[J]. 材料研究学报, 2025, 39(6): 463-473 DOI:10.11901/1005.3093.2024.290

DUAN Yu, WANG Qian, LIU Hongchen, CHE Yuanjun, SHI Lei, BAI Huijuan. Methylene Blue Adsorption Performance of Magnetic Zeolite Prepared from Oil Shale Ash[J]. Earth Science, 2025, 39(6): 463-473 DOI:10.11901/1005.3093.2024.290

油页岩是一种高灰分有机沉积岩，由有机质、矿物质和少量沥青组成^[1]。油页岩中有机质的含量约为15%，无机矿物质的含量较高且种类较多^[2]。用油页岩制取页岩油时，产生大量的灰渣^[3]。长期堆放的灰渣占用土地资源还污染环境，因此综合利用油页岩灰渣是当务之急^[4]。油页岩灰渣的主要成分，有SiO₂、Al₂O₃以及少量的Fe₂O₃、CaO、Na₂O和K₂O。油页岩灰渣的矿物组成和层状结构，与制备分子筛的粘土矿物非常相似。用油页岩灰渣制备分子筛，可大大降低成本。Shawabkeh等^[5]以约旦油页岩灰为原料，采用碱熔水热法合成了P型分子筛；Bao等^[6]以大庆油页岩灰渣为原料，用碱熔水热法制备了X型分子筛。

印染废水污染环境和损害人类的健康。处理印染废水的方法，有物理、化学和生物法等^[7]。吸附法的操作简单、见效快、二次污染风险较小，可用于处理印染废水^[8]。分子筛是一种具有三维空间结构的硅酸铝盐晶体矿物质，具有良好的离子交换能力、特殊的孔隙结构和高比表面积^[9]。但是，用粉末状分子筛处理印染废水时难以与废水快速分离。将强吸附剂(如分子筛、活性炭等)与磁性物质结合，用磁场可实现吸附剂的快速分离。Cheng等^[10]在NaP1型分子筛上负载磁性SrFe₁₂O₁₉，外加磁场实现了分子筛与MB溶液的快速分离。Liu等^[11]在NaA型分子筛上负载Fe₃O₄制备NaA型分子筛，具有良好的磁化和磁稳定性。Fe₃O₄负载量为4.7%的磁性沸石，对Cu²⁺、Pb²⁺的吸附率仍高于95%。鉴于此，本文以北票油页岩灰为原料制备NaX型分子筛和磁性分子筛，研究其对亚甲基蓝(MB)的吸附性能并揭示其机理。

1 实验方法

1.1 实验用材料

北票油页岩、NaOH(96%)、FeCl₃·6H₂O(99%)、乙二醇(99%)、乙酸铵(98%)、亚甲基蓝(MB)、KCl(99%)、Na₂CO₃(99%)、CaCl₂(99%)、Na₂SO₄(99%)和去离子水，电阻为18.25 MΩ。

1.2 实验用仪器

MiniFlex600型X射线衍射仪(XRD)，Zetium波长型X射线荧光光谱仪(XRF)，LakeShore7404型振动样品磁强计(VSM)，ZEISS Sigma 300型扫描电子显微镜(SEM)，Jem-2100F Jeol型透射电子显微镜(TEM)，ASAP 2020型比表面积及孔径分析仪(BET)，Escalab250型X射线光电子能谱仪(XPS)，Nicolet-is5型傅里叶变换红外光谱仪(FTIR)，以及ZS90型电位分析仪(Zeta)。

1.3 磁性分子筛的制备

将油页岩过100目筛子后在950 ℃马弗炉中焙烧6 h，得到油页岩灰(BPA，主晶相是SiO₂)。将BPA与NaOH按照1∶2的质量比混合后研磨均匀，在温度为600 ℃的马弗炉中熔融60 min。将适量熔融后得到的固体粉末与去离子水按照1 g∶6 mL的比例混合，在常温下搅拌3 h后装入聚四氟乙烯水热反应釜中。将反应釜置于温度为80 ℃的恒温干燥箱中反应12 h；反应结束后，过滤反应物并用去离子水将滤渣洗至中性。将滤渣置于110 ℃恒温干燥箱中，干燥5 h后得到分子筛^[12]。

将1 g分子筛和适量的Fe₃O₄颗粒^[13]放入30 mL水中搅拌3 h，然后将其转移到聚四氟乙烯水热反应釜中，将反应釜置于120 ℃的恒温干燥箱中反应7 h。反应结束后，过滤反应物并用去离子水将滤渣洗至中性。将滤渣置于60 ℃恒温干燥箱中，干燥6 h后得到磁性分子筛。

1.4 磁性分子筛性能的表征

用X射线衍仪表征BPA、NaX和Fe₃O₄@NaX型分子筛的物相组成，测试条件为40 kV和20 mA，扫描范围为5°~90°，扫描间隔为0.02°。用荧光光谱仪分析BPA的化学组成。用振动样品磁强计测试Fe₃O₄@NaX型分子筛的磁性。用扫描电子显微镜观察NaX和Fe₃O₄@NaX型分子筛的表面形貌。用透射电子显微镜观察Fe₃O₄@NaX型分子筛的形貌并分析选定区域的元素分布。用比表面积及孔径分析仪测试Fe₃O₄@NaX型分子筛的N₂吸附-脱附等温线和孔径分布曲线。用傅里叶变换红外光谱仪分析吸附前后Fe₃O₄@NaX型分子筛的结构变化，扫描范围为4000~400 cm^-1，分辨率为2 cm^-1。用X射线光电子能谱仪分析吸附前后Fe₃O₄@NaX型分子筛的元素组成。用电位分析仪分析NaX和Fe₃O₄@NaX型分子筛的表面电位。用紫外可见分光光度计(Shimadzu UV2450)测分子筛吸附和再生后分子筛吸附MB后上清液的吸光度。

将磁性分子筛(0.5~2.5 g/L)与一定体积和用量的MB溶液(初始浓度为10~50 mg/L)装入锥形烧瓶中，然后置于不同温度(25~65 ℃)的恒温水浴中，吸附平衡一定时间(0~120 min)后离心分离得到上清液。用紫外可见分光光度计测上清液的吸光度。用0.5 mol/L的氯化钠溶液对吸附后的磁性分子筛进行脱附再生^[14]，用再生后的分子筛对MB溶液进行重复吸附。磁性分子筛对MB的吸附率(R)和平衡吸附量(Q)分别为

R = (c_{0} - c_{e}) / c_{0} \times 100 %

(1)

Q = (c_{0} - c_{e}) V / m

(2)

式中c_e和c₀分别为MB的平衡浓度和初始浓度(mg/L，由与其吸光度之间关系的标准曲线方程求出)，V为MB溶液的体积(L)，m为分子筛的用量(g)。

2 结果和讨论

2.1 Fe₃O₄@NaX型分子筛的物相组成和形貌

由表1可见，BPA的主要成分是SiO₂和Al₂O₃。BPA的XRD谱(图1)中2θ = 27.02°处出现了SiO₂的强衍射峰，表明BPA的主晶相是SiO₂。

表1 BPA的化学组成

Table 1 Main chemical composition of BPA (mass fraction, %)

SiO₂	Al₂O₃	CaO	Fe₂O₃	K₂O	MgO	SO₃	Bal.
60.08	14.38	9.13	5.08	3.66	3.22	2.09	2.35

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图1

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图1 BPA的XRD谱

Fig.1 XRD pattern of BPA

由图2a可见，本文制备的NaX型分子筛的XRD谱与标准卡片(PDF#12-0246)相同。在FTIR谱图2b中993和665 cm^-1处的峰对应TO₄ (T = Si/Al)四面体的不对称和对称拉伸振动峰^[15]，752、558和455 cm^-1处的峰分别对应Si-O-Si/Si-O-Al、Si-O-Al和Al-O/Si-O的弯曲振动峰^[16]。这表明，以BPA为原料制备的NaX型分子筛，由TO₄ (T = Si/Al)、Si-O-Si/Si-O-Al、Si-O-Al和Al-O/Si-O等相组成。

图2

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图2 NaX分子筛的XRD谱和FTIR谱

Fig.2 XRD pattern (a) and FTIR spectrum (b) of NaX zeolite

图3给出了Fe₃O₄@NaX型分子筛的XRD谱。可以看出，随着Fe₃O₄负载量的增加磁性分子筛中Fe₃O₄的衍射峰强度提高，表明Fe₃O₄已经负载在分子筛上^[17]。

图3

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图3 不同Fe₃O₄负载量的Fe₃O₄@NaX型分子筛的XRD谱

Fig.3 XRD patterns of Fe₃O₄@NaX zeolites with different contents of Fe₃O₄ (mass fraction)

从图4可见，合成的分子筛呈现出典型的八面体结构且表面附着一些不规则的黑色球形Fe₃O₄颗粒，也表明Fe₃O₄成功负载在了分子筛上，且分子筛的形貌没有变化。图5a、b表明，球形Fe₃O₄颗粒被包裹在分子筛里。图5c、d表明，Na、Al、Si、O和Fe元素均匀的分布在分子筛中。由O和Fe元素的重叠可以看出，Fe₃O₄颗粒分布在分子筛内部。这表明，这种Fe₃O₄@NaX型分子筛具有核壳结构，即NaX型分子筛形成的壳层包裹了由磁性纳米Fe₃O₄颗粒构成的磁核。

图4

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图4 NaX和Fe₃O₄@NaX型分子筛的SEM照片

Fig.4 SEM images of (a, b) NaX and (c, d) Fe₃O₄@NaX zeolites

图5

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图5 Fe₃O₄@NaX型分子筛的TEM照片和选定区域的元素分布

Fig.5 TEM analysis results of Fe₃O₄@NaX zeolite. (a, b) TEM images; (c, d) selected area and corresponding element distributions

2.2 Fe₃O₄@NaX型分子筛对MB的吸附率以及与MB溶液的分离

图6给出了不同Fe₃O₄负载量Fe₃O₄@NaX型分子筛对MB的吸附性能。可以看出，负载Fe₃O₄后分子筛对MB的吸附率没有较大的变化，而吸附速率有较大的提高。在吸附过程中，分子筛表面所带负电荷与MB所带正电荷之间的静电引力是吸附过程的主要动力。NaX和2.0% Fe₃O₄@NaX (质量分数，下同)型分子筛的电位分别为-28.3和-24.5 mV，表明Fe₃O₄的加入降低了分子筛表面的电位。分子筛表面电位的降低增大了其与MB之间的静电引力，使分子筛对MB的吸附速率提高。随着Fe₃O₄负载量的增大，分子筛对MB的吸附率和吸附速率没有较大的变化，Fe₃O₄的最佳负载量为2.0%。

图6

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图6 Fe₃O₄负载量不同的Fe₃O₄@NaX型分子筛对MB的吸附率

Fig.6 MB removal efficiency of Fe₃O₄@NaX zeolites with different contents of Fe₃O₄

图7给出了2.0% Fe₃O₄@NaX型分子筛的磁滞回线。可以看出，这种分子筛的饱和磁化强度(M_s)为1.71 emu/g，剩余磁化强度(M_r)为0.17 emu/g，矫顽力(H_c)为60.20 emu/g，样品的M_r/M_s比值为0.1 (0~1之间)，表明样品具有永磁特性^[18]。Fe₃O₄的M_s大于1 emu/g，加一外磁场即可将分子筛与MB溶液分离^[19]。本文的实验结果表明，吸附结束后加强度为1500 emu/g的磁场在1 min内即可将分子筛与MB溶液分离(图6插图)。

图7

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图7 2.0% Fe₃O₄@NaX型分子筛的磁滞回线

Fig.7 Magnetic hysteresis loop of 2.0% Fe₃O₄@NaX zeolite

2.3 Fe₃O₄@NaX型分子筛的N₂ 吸附-脱附等温线和孔径分布

图8给出了Fe₃O₄@NaX型分子筛的N₂吸附-脱附等温线和孔径分布曲线。图8表明，这种分子筛的吸附等温线属于IV型，相对压力P/P₀为0.4~1.0时分子筛的脱附等温线为H4型滞后回线，意味着分子筛中有介孔^[20]。分子筛的孔径分布范围为1~20 nm，表明Fe₃O₄@NaX型分子筛属于介孔材料。对Fe₃O₄@NaX型分子筛的BET测试结果表明，其比表面积、孔体积和吸附孔径分别为241.68 m²/g、0.145 cm³/g和8.65 nm。这表明，这种分子筛的比表面积较大，有利于吸附。

图8

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图8 Fe₃O₄@NaX型分子筛的N₂吸附-脱附等温线和孔径分布

Fig.8 N₂ adsorption-desorption isotherms and pore size distribution curve (inset) of the Fe₃O₄@NaX zeolite

2.4 吸附条件对分子筛吸附MB性能的影响

图9给出了在不同条件下分子筛对MB的吸附性能。从图9a可以看出，在吸附的前60 min内，分子筛对MB的吸附率和平衡吸附量从80.85%和38.65 mg/g提高到96.98%和45.19 mg/g，60和120 min的吸附率和平衡吸附量较为接近，因此选择分子筛对MB的吸附时间为60 min。从图9b可见，随着分子筛用量从0.5增加到1.0 g/L对MB的吸附率从69.61%提高到95.54%，因为分子吸附活性位点增多。但是，平衡吸附量从65.25降至30.76 mg/g，因为过多的吸附剂发生团聚，使其总表面积减小^[21]。综合考虑分子筛对MB的吸附效率和吸附能力，选择1 g/L作为后续实验的分子筛用量。从图9c可见，随着MB初始浓度的提高分子筛对MB的吸附率和平衡吸附量分别从98.45%和11.48 mg/g变化到95.64%和44.72 mg/g。其原因是，随着MB初始浓度的提高，分子筛与MB分子之间的浓度梯度增大而使传质推动力增大^[22]。吸附率降低的原因是，一定用量的分子筛提供的表面活性位点数量有限^[23]。MB的初始浓度为50 mg/L时分子筛的吸附性能较高且吸附率高于95%。因此，选择MB的初始浓度为50 mg/L。从图9d可见，随着MB溶液温度的升高吸附率和平衡吸附量分别从96.98%和45.19 mg/g降到92.78%和43.23 mg/g。这表明，分子筛吸附MB的过程为放热过程^[24]，25 ℃是最佳吸附温度。

图9

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图9 吸附条件对分子筛吸附性能的影响

Fig.9 Effects of adsorption conditions on the adsorption performance of the zeolite. (a) effect of adsorption time, (b) effect of zeolite dosage, (c) effect of the initial concentration of MB, (d) effect of MB solution temperature

图10给出了NaCl、KCl、CaCl₂、Na₂CO₃和Na₂SO₄ 5种盐和盐度对分子筛吸附MB的影响。可以看出，溶液中的盐使分子筛对MB的吸附率降低。其原因是，存在盐离子的离子效应及其与MB之间的竞争吸附。当阳离子相同时，阴离子对MB吸附率没有显著的影响，因为静电引力是主要的吸附力；而阴离子相同时，Ca²⁺对MB吸附率的影响比K⁺和Na⁺的大，因为在浓度相同的条件下Ca²⁺带两个正电荷，Ca²⁺与MB之间对吸附位点较大的竞争使其对MB吸附率的影响更大。

图10

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图10 几种盐和盐度对分子筛吸附MB的影响

Fig.10 Effects of different salts and salinities on the MB adsorption performance of the zeolite

表2列出了Fe₃O₄@NaX型分子筛对MB的吸附性能与其他吸附剂的比较。可以看出，本文合成的Fe₃O₄@NaX型分子筛对MB的吸附性能较好。

表2 不同吸附剂对MB的吸附性能

Table 2 MB adsorption capacities of diﬀerent adsorbents

Adsorbents	Time / min	Dosage / g·L^-1	Initial concentration / mg·L^-1	pH value	Temperature / ^oC	Adsorption capacity / mg·g^-1	Ref.
Fe₃O₄@NaX	60	1	50	Natural	25	45.19	This work
WO₃	3	0.05	15	Natural	Natural	1.64	[25]
Zeolite HY-Fe₃O₄ from Zeolite HY and Fe₃O₄	40	1.186	10.23	9	53.9	3.24	[26]
Natural zeolite from Sigmae-Aldrich	120	0.6	20	Natural	25	9.19	[27]
A mixture of zeolite A and P synthesized from electrolytic manganese residue	200	6	200	6	40	33.57	[28]
Zeo-FPT	40	0.5	10	8	25	0.438	[29]
Magnetic graphene oxide	240	0.15	45	9	25	306.5	[30]
Fe₃O₄@UIO-66-NH₂	90	0.004	4	9	Natural	9.53	[31]

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2.5 Fe₃O₄@NaX型分子筛的吸附动力学和吸附模型

将0.1 g的2.0% Fe₃O₄@NaX型分子筛与100 mL的浓度为50 mg/L的MB溶液装入锥形烧瓶中，然后置于不同温度(25、35、45、55和65 ℃)的恒温水浴进行吸附实验，得出不同吸附时间(5、15、30、60、90、120 min)下分子筛对MB的平衡吸附量，采用式(3)~(5)所示的拟一级、拟二级和颗粒内扩散动力学模型公式对上述实验得到的实验数据进行拟合，拟合得到的动力学参数列于表3。从表3可见，用拟二级动力学模型拟合的q_e值与实验q_e值接近，R²接近1，表明Fe₃O₄@NaX型分子筛对MB的吸附符合拟二级动力学模型。同时，颗粒内扩散动力学模型中的c值不为0，表明颗粒内扩散并不是Fe₃O₄@NaX型分子筛吸附MB速率的唯一控制因素。

表3 Fe₃O₄@NaX型分子筛吸附MB的动力学参数

Table 3 Kinetics parameters for MB adsorption on the Fe₃O₄@NaX zeolite

Models	Temperature	25 ^oC	35 ^oC	45 ^oC	55 ^oC	65 ^oC
Experiment	q_e,exp / mg·g^-1	47.80	45.07	52.38	52.38	50.94
Pseudo-first-order	q_e,cal / mg·g^-1	5.64	4.68	4.02	3.80	4.41
	k₁ / min^-1	0.0115	0.0094	0.0085	0.0042	0.0041
	R²	0.6108	0.4593	0.2464	0.3032	0.2157
Pseudo-second-order	q_e,cal / mg·g^-1	46.32	43.42	50.63	49.85	47.78
	k₂ / g·mg^-1·min^-1	0.0237	0.0339	0.0599	0.1242	0.6337
	R²	0.9999	0.9999	0.9999	0.9999	0.9997
Intraparticle diffusion	c / mg·g^-1	39.50	37.98	45.76	47.64	45.48
	k_p / mg·g^-1·min^-1/2	0.0115	0.0094	0.0085	0.0042	0.0041
	R²	0.6079	0.4797	0.4130	0.4876	0.4487

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拟一级动力学模型为

l n (q_{e} - q_{t}) = l n q_{e} - k_{1} t

(3)

拟二级动力学模型为

\frac{t}{q_{t}} = \frac{1}{k_{2} q_{e}^{2}} + \frac{t}{q_{e}}

(4)

颗粒内扩散动力学模型为

q_{t} = k_{p} t^{1 / 2} + c

(5)

式中，q_t和q_e(mg/g)分别为任意时间的吸附量和MB平衡吸附量，q_e,exp和q_e,cal(mg/g)分别为实验q_e值和理论q_e值，k₁(min^-1)为准一级吸附速率常数，k₂(g·mg^-1·min^-1)为准二级吸附速率常数，k_p(mg·g^-1·min^-1/2)为内扩散动力学吸附速率常数，c(mg/g)为反映边界层对吸附速率影响的常数。

表4列出了Fe₃O₄@NaX型分子筛吸附MB过程的Langmuir、Freundlich和Dubinin-Radushkevich吸附等温线参数。可以看出，Fe₃O₄@NaX型分子筛对MB的吸附遵循Langmuir吸附等温线模型，说明是单层吸附。

表4 Fe₃O₄@NaX型分子筛吸附MB的等温线参数

Table 4 Isotherms parameters for MB adsorption on the Fe₃O₄@NaX zeolite

Langmuir

Freundlich

Dubinin-Radushkevich

q_m

/ mg·g^-1

K_L

/ L·mg^-1

R²

K_F

/ mg·g^-1

R²

q_m

/ mg·g^-1

K_DR

/ mol²·J^-2

R²

57.3394

1.6998

0.9997

34.1461

1.9409

0.9495

42.6702

5.32×10^-8

0.9734

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Langmuir吸附等温线模型为

\frac{c_{e}}{q_{e}} = \frac{c_{e}}{q_{m}} + \frac{1}{q_{m} K_{L}}

(6)

Freundlich吸附等温线模型为

l n q_{e} = \frac{1}{n} l n c_{e} + l n K_{F}

(7)

Dubinin-Radushkevich吸附等温线模型为

l n q_{e} = l n q_{m} - K_{D R} ε^{2}

(8)

ε = R T l n (1 + 1 / c_{e})

(9)

式中，q_m(mg/g)为最大理论的吸附量，K_L(L/mg)为Langmuir常数，K_F(mg/g)为Freundlich常数，K_DR(mol²/J²)为吸附能相关参数，n为与温度有关大于1的常数，R(8.314 J·mol^-1·K^-1)为理想气体摩尔常数， $ε$ 为Polanyi吸附势，T为Kelvin温度。

2.6 Fe₃O₄@NaX型分子筛的吸附热力学、吸附机理和重复使用性能

根据在不同温度的吸附实验数据和范特霍夫方程计算出吸附过程的ΔG、ΔH和ΔS，结果列于表5。ΔG < 0表明，Fe₃O₄@NaX型分子筛对MB的吸附属于自发吸附。ΔG随着温度的升高而增大，表明提高温度不利于这种分子筛对MB的吸附。ΔH = -16.3922 kJ/mol和ΔS = -26.1432 J/mol表明，吸附是一个放热的熵减过程^[32]。

表5 Fe₃O₄@NaX型分子筛吸附MB的热力学参数

Table 5 Thermodynamic parameters for MB adsorption on the Fe₃O₄@NaX zeolite

Temperature / K	K_c	ΔG / kJ·mol^-1	ΔH / kJ·mol^-1	ΔS / J·mol^-1·K^-1
298.15	32.1413	-8.6019	-16.3922	-26.1432
308.15	26.4178	-8.3880
318.15	24.4721	-8.2136
328.15	16.9428	-7.7205
338.15	12.8492	-7.1782

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Van't Hoff方程为

l n K_{c} = - \frac{Δ H}{R T} + \frac{Δ S}{R}

(10)

K_{c} = \frac{c_{0} - c_{e}}{c_{e}}

(11)

Δ G = - R T l n K_{c}

(12)

式中，K_c为吸附过程的平衡常数，ΔG(kJ/mol)为吸附过程的Gibbs自由能，ΔH(kJ/mol)为等温吸附过程的焓变，ΔS(kJ/(mol·K))为等温吸附过程的熵变。

根据XPS谱(图11)和FTIR谱(图12)研究了Fe₃O₄@NaX型分子筛对MB的吸附机理。

图11

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图11 Fe₃O₄@NaX型分子筛吸附前后的XPS谱

Fig.11 XPS spectra of Fe₃O₄@NaX zeolite before and after adsorption: (a) survey spectra, (b) Na 1s, (c) Si 2p, (d) C 1s

图12

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图12 Fe₃O₄@NaX型分子筛吸附前后的FTIR谱

Fig.12 FTIR spectra of Fe₃O₄@NaX zeolite before and after adsorption

从图11可以看出，吸附前后分子筛的XPS全谱没有明显的变化，吸附后的XPS谱中出现了新的N 1s峰。这表明，MB已经被分子筛吸附。吸附后分子筛中N的结合能(400.4 eV)比纯MB中N的结合能(399.2 ± 0.2) eV稍大，表明MB和分子筛通过N原子发生了相互作用^[33]，促进了分子筛对MB的吸附。

图12给出了分子筛吸附MB前后的FTIR谱。谱中562 cm^-1处的峰归属于Fe-O的振动峰。XPS谱中出现了Na、Si、Al、Fe和O元素的衍射峰，再次确认本文成功地制备出磁性分子筛。同时，1387和1352 cm^-1处出现的MB的C-N伸缩振动峰和CH₃基团的振动峰表明，分子筛能吸附MB^[34]；在3440和1644 cm^-1处的峰归属于O-H和N-H的伸缩振动峰，-OH基团来自分子筛表面和孔道中的水分子，表明Fe₃O₄@NaX型分子筛与MB分子之间形成了氢键，能促进分子筛对MB的吸附。

图13表明，这种分子筛的电位为-24.5 mV。基于以上分析提出一种Fe₃O₄@NaX型分子筛吸附MB的机理：MB分子所带的正电荷与分子筛表面的负电荷之间的静电吸引力，促进了分子筛对MB分子的吸附；分子筛表面的-OH基团与MB分子中的N原子形成氢键，进一步促进了吸附；分子筛具有丰富的孔结构，MB分子通过孔隙扩散或毛细管冷凝渗透到分子筛内并被吸附。

图13

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图13 Fe₃O₄@NaX型分子筛吸附MB的机理

Fig.13 Mechanism of adsorption of MB by Fe₃O₄@NaX molecular sieve

图14给出了Fe₃O₄@NaX型分子筛的可重复利用性能以及吸附和脱附前后的XRD谱。图14a表明，经过5次循环再生吸附，分子筛对MB的吸附率基本不变。图14b中的XRD谱表明，经过5次循环再生后分子筛的结构没有明显的改变。这表明，这种磁性分子筛的结构稳定、具有可再生重复使用性能。

图14

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图14 Fe₃O₄@NaX型分子筛的可重复利用性能和洗脱前后的XRD谱

Fig.14 Reusability (a) and XRD patterns before and after elution (b) of Fe₃O₄@NaX zeolite

3 结论

以(北票)油页岩灰为原料可制备Fe₃O₄@NaX型磁性分子筛。Fe₃O₄@NaX型分子筛对MB的吸附遵循拟二级动力学和Langmuir等温线模型，是自发的、放热的熵减过程，吸附的推动力为静电引力、氢键和孔内扩散。经过5次循环再生后，分子筛对MB的吸附率不变且其结构没有明显的改变。加一外磁场可将这种磁性分子筛与MB溶液快速分离。这种分子筛的结构稳定，具有较好的可再生重复使用性能。

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In this study, we have reported a facile preparation of zeolite 4A from Ethiopia kaolin for the adsorptive removal of methylene blue (MB) dye. The formation of highly crystalline and pure phase zeolite 4A with cubic morphology was confirmed by powder X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis. The efficiency of zeolite 4A for abatement of MB was investigated at varying adsorption parameters. Response surface methodology coupled with Box Behnken Design (RSM-BBD) was employed to optimize adsorption parameters. High regression (R-2 = 0.9947) and the low probability (p value <0.0001) values signify the validity of the quadratic model to predict the removal (%) of MB. The maximum MB removal (%) was 99.37% at the optimum combination of 50 mL of 10 mg/L of MB, 39.05 mg zeolite 4A, and 179.82 contact time (min). The adjusted R-square (R-adj(2)) and standard deviations (SD) were validated the best fitting of pseudo-second-order kinetics and the Langmuir isotherm model for experimental values. The maximum adsorption capacity (Q(max)) of zeolite 4A towards MB was found to be 44.35 mg g(-1). Electrostatic interaction, hydrogen bond, and n to pi bond formation are predicted to be the plausible interaction mechanism of MB to the surface of zeolite 4A. The Fukui function and vibration analysis based on the density functional theory (DFT) further strengthened the proposed mechanism.

[24]

Ioannou

, Karasavvidis

, Dimirkou

, et al.

Adsorption of methylene blue and methyl red dyes from aqueous solutions onto modified zeolites

[J]. Water Sci. Technol., 2013, 67(5): 1129

DOI PMID [本文引用: 1]

Zeolite, hematite, modified zeolite and commercial activated charcoal were examined for their ability to remove methylene blue (MB) and methyl red (MR) from their aqueous solutions. Modified zeolite and hematite were produced according to the Schwertmann and Cornell method while zeolite and commercial activated charcoal were obtained from S&B and Fluka AG companies, respectively. Adsorption experiments were conducted at three different adsorbent-to-solution ratios, namely 8, 16 and 24 g/L under environmental conditions and continuous stirring. Equilibrium isotherms of MB and MR were studied at different initial concentrations (from 5 × 10(-4) to 5 × 10(-3) g/L). MB adsorption kinetics were also studied. The maximum adsorption of MB and MR from their aqueous solutions was achieved at 24 g/L (adsorbent-to-dye solution ratio) after 1 h and was equal to 100% (MB) on modified zeolite and 99% (MR) on commercial activated charcoal, respectively. All the other materials achieved intermediate values of dye adsorption. From the applied kinetic models, the pseudo-second-order equation best described the adsorption of MB and MR. Consequently, modified zeolite showed the highest adsorption capacity for MB, while commercial activated charcoal showed the highest adsorption capacity of MR. The studied adsorbents can be used as filters to remove dyes from wastewaters.

[25]

Dadashi

, Bahram

, Farhadi

, et al.

Photodecoration of tungsten oxide nanoparticles onto eggshell as an ultra-fast adsorbent for removal of MB dye pollutant

[J]. Sci. Rep., 2024, 14(1): 14478

DOI PMID [本文引用: 1]

Nowadays, the use of natural wastes and adsorbents along with their modification by simple and new methods based on metal oxides to remove dye pollutants has been the focus of many researchers. In this study, for the first time, simple and low-cost modification of eggshell (EGS) with tungsten oxide (WO) based on the photochemical modification method as a green, ultra-fast, cost-effective, and biodegradable adsorbent is reported to remove of methylene blue (MB) dye pollutant. The EGS modified by WO was investigated by EDX, EDX mapping, XRD, FE-SEM, and UV-Vis Diffuse Reflectance (DRS) analyses. The obtained results show that the modified EGS by WO has more than ten times (78.5%) the ability to remove MB dye pollutant within 3 min compared to bare EGS (11%). Various parameters including dye pollutant pH, dye concentration, adsorbent dosage, and reusability of the WO/EGS adsorbent for removal of MB dye pollutant were investigated and the result show that the adsorbent capacity of WO/EGS is 1.64 mg g. EGS adsorbent The synthesis of WO/EGS adsorbent with a novel photochemical method as a fast and very cheap adsorbent with excellent efficiency can be a promising alternative adsorbent for various purposes in removing dye pollutants from water environments.© 2024. The Author(s).

[26]

Majid

, Abdulrazak

A A

, Noori

W A H

Modification of zeolite by magnetic nanoparticles for organic dye removal

[J]. Arab. J. Sci. Eng., 2019, 44(6): 5457

[本文引用: 1]

[27]

Hor

K Y

, Chee

J M C

, Chong

M N

, et al.

Evaluation of physicochemical methods in enhancing the adsorption performance of natural zeolite as low-cost adsorbent of methylene blue dye from wastewater

[J]. J. Clean. Prod., 2016, 118: 197

[本文引用: 1]

[28]

C X

, Zhong

, Wang

, et al.

Removal of basic dye (methylene blue) from aqueous solution using zeolite synthesized from electrolytic manganese residue

[J]. J. Ind. Eng. Chem., 2015, 23: 344

[本文引用: 1]

[29]

Alhogbi

B G

, Al Balawi

G S

An investigation of a natural biosorbent for removing methylene blue dye from aqueous solution

[J]. Molecules, 2023, 28(6): 2785

[本文引用: 1]

[30]

Guo

Y F

, Deng

, Zhu

J Y

, et al.

Removal of mercury(II) and methylene blue from a wastewater environment with magnetic graphene oxide: adsorption kinetics, isotherms and mechanism

[J]. RSC Adv., 2016, 6(86): 82523

[本文引用: 1]

[31]

Zhang

Y M

, Dai

T L

, Zhang

, et al.

Fe₃O₄@UiO-66-NH₂ core-shell nanohybrid as stable heterogeneous catalyst for Knoevenagel condensation

[J]. Chin. J. Catal., 2016, 37(12): 2106

[本文引用: 1]

张艳梅, 戴田霖, 张帆等.

核壳结构Fe₃O₄@UiO-66-NH₂磁性纳米复合材料的合成及其催化Knoevenagel缩合反应性能

[J]. 催化学报, 2016, 37(12): 2106

DOI [本文引用: 1]

金属有机骨架（MOF）材料是由过渡金属离子与有机配体通过配位键连接构成的高度有序的超分子化合物.这类材料比表面积大，孔隙率高，热稳定性好，而且具有规整可调控的孔结构、易于功能化的骨架金属离子和有机配体，在多相催化领域具有潜在应用前景.将纳米尺寸的MOF材料等多孔材料作为催化剂，可以提高反应传质效率，从而提高催化反应活性，但纳米MOF催化剂的分离和回收困难.将磁性纳米粒子和MOF材料组装成核壳结构的磁性MOF材料，不仅可简化催化剂的分离回收，而且通过控制壳层材料的厚度可以实现催化剂的高活性和高选择性.我们曾将磁核Fe3O4纳米粒子交替放入含有一种MOF材料前体的DMF溶液中，采用层层组装法制备了磁性Fe3O4@UiO-66-NH2纳米复合材料.经过十步组装后的材料的透射电镜（TEM）结果证实为核壳结构.但未出现明显的UiO-66-NH2的X射线衍射（XRD）特征峰，说明壳层材料UiO-66-NH2的结晶度较低；同时由于其孔结构的破坏或堵塞，在反应中出现明显失活.本文进一步改进自组装方法制备了核壳结构的磁性Fe3O4@UiO-66-NH2纳米复合材料，用XRD、傅里叶变换红外光谱（FT-IR）、TEM、扫描电镜（SEM）和氮气吸附等方法对材料的组成和结构进行了表征，并考察了其在Knoevenagel缩合反应中的催化性能.结果表明，所制材料是以Fe3O4为核，以UiO-66-NH2为壳的核-壳结构材料.经三次组装后出现了一系列UiO-66-NH2的XRD特征峰，说明采用新方法制备的复合材料中壳层材料UiO-66-NH2结晶度高，晶体结构规整.N2吸附-脱附结果表明，材料具有较高的比表面积和孔容.该复合材料在Knoevenagel缩合反应中表现出与纳米UiO-66-NH2相当或更好的催化活性和选择性，而且因壳层材料的孔道限阈效应而对底物表现出尺寸选择性.由于材料结晶度和晶体结构规整度的提高，催化剂稳定性更好，通过简单磁性分离即可分离和回收催化剂，循环使用4次而未出现明显失活.相对于本课题组之前报道的Fe3O4@CuBTC-NH2，Fe3O4@IRMOF-3和Fe3O4@UiO-66-NH2材料，本文所制的Fe3O4@UiO-66-NH2是一类结构更加稳定的高效固体碱催化剂.

[32]

Cao

J S

, Lin

J X

, Fang

, et al.

A new absorbent by modifying walnut shell for the removal of anionic dye: kinetic and thermodynamic studies

[J]. Bioresour. Technol., 2014, 163: 199

[本文引用: 1]

[33]

Nezamzadeh-Ejhieh

, Karimi-Shamsabadi

Comparison of photocatalytic efficiency of supported CuO onto micro and nano particles of zeolite X in photodecolorization of methylene blue and methyl orange aqueous mixture

[J]. Appl. Catal., 2014, 477: 83

[本文引用: 1]

[34]

Bai

S X

, Zhou

L M

, Chang

Z B

, et al.

Synthesis of Na-X zeolite from Longkou oil shale ash by alkaline fusion hydrothermal method

[J]. Carbon Resour. Convers., 2018, 1(3): 245

[本文引用: 1]

Experimental study on the thermophysical properties of Jimsar oil shale

2023

... 油页岩是一种高灰分有机沉积岩，由有机质、矿物质和少量沥青组成^[1].油页岩中有机质的含量约为15%，无机矿物质的含量较高且种类较多^[2].用油页岩制取页岩油时，产生大量的灰渣^[3].长期堆放的灰渣占用土地资源还污染环境，因此综合利用油页岩灰渣是当务之急^[4].油页岩灰渣的主要成分，有SiO₂、Al₂O₃以及少量的Fe₂O₃、CaO、Na₂O和K₂O.油页岩灰渣的矿物组成和层状结构，与制备分子筛的粘土矿物非常相似.用油页岩灰渣制备分子筛，可大大降低成本.Shawabkeh等^[5]以约旦油页岩灰为原料，采用碱熔水热法合成了P型分子筛；Bao等^[6]以大庆油页岩灰渣为原料，用碱熔水热法制备了X型分子筛. ...

Modified oil shale ash and oil shale ash zeolite for the removal of Cd²⁺ ion from aqueous solutions

2019

Alkali activation of oil shale ash based ceramics

2012

Synthesis of mesoporous silica SBA-15 from geothermal sludge

2023

Conversion of oil shale ash into zeolite for cadmium and lead removal from wastewater

2004

Adsorption of heavy metal ions from aqueous solutions by zeolite based on oil shale ash: kinetic and equilibrium studies

2013

Enhanced adsorption of dyes on microwave-assisted synthesized magnetic zeolite-hydroxyapatite nanocomposite

2019

... 印染废水污染环境和损害人类的健康.处理印染废水的方法，有物理、化学和生物法等^[7].吸附法的操作简单、见效快、二次污染风险较小，可用于处理印染废水^[8].分子筛是一种具有三维空间结构的硅酸铝盐晶体矿物质，具有良好的离子交换能力、特殊的孔隙结构和高比表面积^[9].但是，用粉末状分子筛处理印染废水时难以与废水快速分离.将强吸附剂(如分子筛、活性炭等)与磁性物质结合，用磁场可实现吸附剂的快速分离.Cheng等^[10]在NaP1型分子筛上负载磁性SrFe₁₂O₁₉，外加磁场实现了分子筛与MB溶液的快速分离.Liu等^[11]在NaA型分子筛上负载Fe₃O₄制备NaA型分子筛，具有良好的磁化和磁稳定性.Fe₃O₄负载量为4.7%的磁性沸石，对Cu²⁺、Pb²⁺的吸附率仍高于95%.鉴于此，本文以北票油页岩灰为原料制备NaX型分子筛和磁性分子筛，研究其对亚甲基蓝(MB)的吸附性能并揭示其机理. ...

Adsorption and recovery of low concentration coal-bed methane by zeolite ZSM-5

2016

沸石ZSM-5吸附回收低浓度煤层气中CH₄

2016

Utilization of red mud waste into mesoporous ZSM-5 for methylene blue adsorption-desorption studies

2021

Feasible low-cost conversion of red mud into magnetically separated and recycled hybrid SrFe₁₂O₁₉@NaP1 zeolite as a novel wastewater adsorbent

2021

Magnetic zeolite NaA: synthesis, characterization based on metakaolin and its application for the removal of Cu²⁺, Pb²⁺

2013

The methyl blue adsorption performance and mechanism of NaX zeolite synthesized from Huadian oil shale ash

2023

... 将油页岩过100目筛子后在950 ℃马弗炉中焙烧6 h，得到油页岩灰(BPA，主晶相是SiO₂).将BPA与NaOH按照1∶2的质量比混合后研磨均匀，在温度为600 ℃的马弗炉中熔融60 min.将适量熔融后得到的固体粉末与去离子水按照1 g∶6 mL的比例混合，在常温下搅拌3 h后装入聚四氟乙烯水热反应釜中.将反应釜置于温度为80 ℃的恒温干燥箱中反应12 h；反应结束后，过滤反应物并用去离子水将滤渣洗至中性.将滤渣置于110 ℃恒温干燥箱中，干燥5 h后得到分子筛^[12]. ...

Synthesis and characterization of magnetic core with two shells: mordenite zeolite and CuO to form Fe₃O₄@MOR@CuO core-shell: as a visible light driven photocatalyst

2017

... 将1 g分子筛和适量的Fe₃O₄颗粒^[13]放入30 mL水中搅拌3 h，然后将其转移到聚四氟乙烯水热反应釜中，将反应釜置于120 ℃的恒温干燥箱中反应7 h.反应结束后，过滤反应物并用去离子水将滤渣洗至中性.将滤渣置于60 ℃恒温干燥箱中，干燥6 h后得到磁性分子筛. ...

Synthesis, characterization, and use of an amine-functionalized mesoporous silica SBA-15 for the removal of Congo Red from aqueous media

2023

... 将磁性分子筛(0.5~2.5 g/L)与一定体积和用量的MB溶液(初始浓度为10~50 mg/L)装入锥形烧瓶中，然后置于不同温度(25~65 ℃)的恒温水浴中，吸附平衡一定时间(0~120 min)后离心分离得到上清液.用紫外可见分光光度计测上清液的吸光度.用0.5 mol/L的氯化钠溶液对吸附后的磁性分子筛进行脱附再生^[14]，用再生后的分子筛对MB溶液进行重复吸附.磁性分子筛对MB的吸附率(R)和平衡吸附量(Q)分别为 ...

Characterization and application of lamellar zeolite-X prepared from kaolin

2024

... 由图2a可见，本文制备的NaX型分子筛的XRD谱与标准卡片(PDF#12-0246)相同.在FTIR谱图2b中993和665 cm^-1处的峰对应TO₄ (T = Si/Al)四面体的不对称和对称拉伸振动峰^[15]，752、558和455 cm^-1处的峰分别对应Si-O-Si/Si-O-Al、Si-O-Al和Al-O/Si-O的弯曲振动峰^[16].这表明，以BPA为原料制备的NaX型分子筛，由TO₄ (T = Si/Al)、Si-O-Si/Si-O-Al、Si-O-Al和Al-O/Si-O等相组成. ...

Synthesis and characterization of zeolite X obtained from coal gangue for adsorption of Cu²⁺

2021

Feasible synthesis of magnetic zeolite from red mud and coal gangue: preparation, transformation and application

2023

... 图3给出了Fe₃O₄@NaX型分子筛的XRD谱.可以看出，随着Fe₃O₄负载量的增加磁性分子筛中Fe₃O₄的衍射峰强度提高，表明Fe₃O₄已经负载在分子筛上^[17]. ...

Structural, magnetic and electromagnetic properties of SrFe₁₂O₁₉ ferrite with particles aligned in a magnetic field

2017

... 图7给出了2.0% Fe₃O₄@NaX型分子筛的磁滞回线.可以看出，这种分子筛的饱和磁化强度(M_s)为1.71 emu/g，剩余磁化强度(M_r)为0.17 emu/g，矫顽力(H_c)为60.20 emu/g，样品的M_r/M_s比值为0.1 (0~1之间)，表明样品具有永磁特性^[18].Fe₃O₄的M_s大于1 emu/g，加一外磁场即可将分子筛与MB溶液分离^[19].本文的实验结果表明，吸附结束后加强度为1500 emu/g的磁场在1 min内即可将分子筛与MB溶液分离(图6插图). ...

Systematic review on applicability of magnetic iron oxides-integrated photocatalysts for degradation of organic pollutants in water

2019

Synthesize and characterize of Fe₃O₄/zeolite 4A magnetic nanocomposite

2022

... 图8给出了Fe₃O₄@NaX型分子筛的N₂吸附-脱附等温线和孔径分布曲线.图8表明，这种分子筛的吸附等温线属于IV型，相对压力P/P₀为0.4~1.0时分子筛的脱附等温线为H4型滞后回线，意味着分子筛中有介孔^[20].分子筛的孔径分布范围为1~20 nm，表明Fe₃O₄@NaX型分子筛属于介孔材料.对Fe₃O₄@NaX型分子筛的BET测试结果表明，其比表面积、孔体积和吸附孔径分别为241.68 m²/g、0.145 cm³/g和8.65 nm.这表明，这种分子筛的比表面积较大，有利于吸附. ...

Effective removal of ruthenium (III) ions from wastewater by amidoxime modified zeolite X

2019

... 图9给出了在不同条件下分子筛对MB的吸附性能.从图9a可以看出，在吸附的前60 min内，分子筛对MB的吸附率和平衡吸附量从80.85%和38.65 mg/g提高到96.98%和45.19 mg/g，60和120 min的吸附率和平衡吸附量较为接近，因此选择分子筛对MB的吸附时间为60 min.从图9b可见，随着分子筛用量从0.5增加到1.0 g/L对MB的吸附率从69.61%提高到95.54%，因为分子吸附活性位点增多.但是，平衡吸附量从65.25降至30.76 mg/g，因为过多的吸附剂发生团聚，使其总表面积减小^[21].综合考虑分子筛对MB的吸附效率和吸附能力，选择1 g/L作为后续实验的分子筛用量.从图9c可见，随着MB初始浓度的提高分子筛对MB的吸附率和平衡吸附量分别从98.45%和11.48 mg/g变化到95.64%和44.72 mg/g.其原因是，随着MB初始浓度的提高，分子筛与MB分子之间的浓度梯度增大而使传质推动力增大^[22].吸附率降低的原因是，一定用量的分子筛提供的表面活性位点数量有限^[23].MB的初始浓度为50 mg/L时分子筛的吸附性能较高且吸附率高于95%.因此，选择MB的初始浓度为50 mg/L.从图9d可见，随着MB溶液温度的升高吸附率和平衡吸附量分别从96.98%和45.19 mg/g降到92.78%和43.23 mg/g.这表明，分子筛吸附MB的过程为放热过程^[24]，25 ℃是最佳吸附温度. ...

Properties of methylene blue in the presence of zeolite nanoparticles

2016

Preparation of zeolite 4A for adsorptive removal of methylene blue: optimization, kinetics, isotherm, and mechanism study

2022

Adsorption of methylene blue and methyl red dyes from aqueous solutions onto modified zeolites

2013

Photodecoration of tungsten oxide nanoparticles onto eggshell as an ultra-fast adsorbent for removal of MB dye pollutant

2024

... MB adsorption capacities of diﬀerent adsorbents

Table 2

Adsorbents	Time / min	Dosage / g·L^-1	Initial concentration / mg·L^-1	pH value	Temperature / ^oC	Adsorption capacity / mg·g^-1	Ref.
Fe₃O₄@NaX	60	1	50	Natural	25	45.19	This work
WO₃	3	0.05	15	Natural	Natural	1.64	[25]
Zeolite HY-Fe₃O₄ from Zeolite HY and Fe₃O₄	40	1.186	10.23	9	53.9	3.24	[26]
Natural zeolite from Sigmae-Aldrich	120	0.6	20	Natural	25	9.19	[27]
A mixture of zeolite A and P synthesized from electrolytic manganese residue	200	6	200	6	40	33.57	[28]
Zeo-FPT	40	0.5	10	8	25	0.438	[29]
Magnetic graphene oxide	240	0.15	45	9	25	306.5	[30]
Fe₃O₄@UIO-66-NH₂	90	0.004	4	9	Natural	9.53	[31]

2.5 Fe3O4@NaX型分子筛的吸附动力学和吸附模型

将0.1 g的2.0% Fe₃O₄@NaX型分子筛与100 mL的浓度为50 mg/L的MB溶液装入锥形烧瓶中，然后置于不同温度(25、35、45、55和65 ℃)的恒温水浴进行吸附实验，得出不同吸附时间(5、15、30、60、90、120 min)下分子筛对MB的平衡吸附量，采用式(3)~(5)所示的拟一级、拟二级和颗粒内扩散动力学模型公式对上述实验得到的实验数据进行拟合，拟合得到的动力学参数列于表3.从表3可见，用拟二级动力学模型拟合的q_e值与实验q_e值接近，R²接近1，表明Fe₃O₄@NaX型分子筛对MB的吸附符合拟二级动力学模型.同时，颗粒内扩散动力学模型中的c值不为0，表明颗粒内扩散并不是Fe₃O₄@NaX型分子筛吸附MB速率的唯一控制因素. ...

Modification of zeolite by magnetic nanoparticles for organic dye removal

2019

... MB adsorption capacities of diﬀerent adsorbents

Table 2

Adsorbents	Time / min	Dosage / g·L^-1	Initial concentration / mg·L^-1	pH value	Temperature / ^oC	Adsorption capacity / mg·g^-1	Ref.
Fe₃O₄@NaX	60	1	50	Natural	25	45.19	This work
WO₃	3	0.05	15	Natural	Natural	1.64	[25]
Zeolite HY-Fe₃O₄ from Zeolite HY and Fe₃O₄	40	1.186	10.23	9	53.9	3.24	[26]
Natural zeolite from Sigmae-Aldrich	120	0.6	20	Natural	25	9.19	[27]
A mixture of zeolite A and P synthesized from electrolytic manganese residue	200	6	200	6	40	33.57	[28]
Zeo-FPT	40	0.5	10	8	25	0.438	[29]
Magnetic graphene oxide	240	0.15	45	9	25	306.5	[30]
Fe₃O₄@UIO-66-NH₂	90	0.004	4	9	Natural	9.53	[31]

2.5 Fe3O4@NaX型分子筛的吸附动力学和吸附模型

将0.1 g的2.0% Fe₃O₄@NaX型分子筛与100 mL的浓度为50 mg/L的MB溶液装入锥形烧瓶中，然后置于不同温度(25、35、45、55和65 ℃)的恒温水浴进行吸附实验，得出不同吸附时间(5、15、30、60、90、120 min)下分子筛对MB的平衡吸附量，采用式(3)~(5)所示的拟一级、拟二级和颗粒内扩散动力学模型公式对上述实验得到的实验数据进行拟合，拟合得到的动力学参数列于表3.从表3可见，用拟二级动力学模型拟合的q_e值与实验q_e值接近，R²接近1，表明Fe₃O₄@NaX型分子筛对MB的吸附符合拟二级动力学模型.同时，颗粒内扩散动力学模型中的c值不为0，表明颗粒内扩散并不是Fe₃O₄@NaX型分子筛吸附MB速率的唯一控制因素. ...

Evaluation of physicochemical methods in enhancing the adsorption performance of natural zeolite as low-cost adsorbent of methylene blue dye from wastewater

2016

... MB adsorption capacities of diﬀerent adsorbents

Table 2

Adsorbents	Time / min	Dosage / g·L^-1	Initial concentration / mg·L^-1	pH value	Temperature / ^oC	Adsorption capacity / mg·g^-1	Ref.
Fe₃O₄@NaX	60	1	50	Natural	25	45.19	This work
WO₃	3	0.05	15	Natural	Natural	1.64	[25]
Zeolite HY-Fe₃O₄ from Zeolite HY and Fe₃O₄	40	1.186	10.23	9	53.9	3.24	[26]
Natural zeolite from Sigmae-Aldrich	120	0.6	20	Natural	25	9.19	[27]
A mixture of zeolite A and P synthesized from electrolytic manganese residue	200	6	200	6	40	33.57	[28]
Zeo-FPT	40	0.5	10	8	25	0.438	[29]
Magnetic graphene oxide	240	0.15	45	9	25	306.5	[30]
Fe₃O₄@UIO-66-NH₂	90	0.004	4	9	Natural	9.53	[31]

2.5 Fe3O4@NaX型分子筛的吸附动力学和吸附模型

将0.1 g的2.0% Fe₃O₄@NaX型分子筛与100 mL的浓度为50 mg/L的MB溶液装入锥形烧瓶中，然后置于不同温度(25、35、45、55和65 ℃)的恒温水浴进行吸附实验，得出不同吸附时间(5、15、30、60、90、120 min)下分子筛对MB的平衡吸附量，采用式(3)~(5)所示的拟一级、拟二级和颗粒内扩散动力学模型公式对上述实验得到的实验数据进行拟合，拟合得到的动力学参数列于表3.从表3可见，用拟二级动力学模型拟合的q_e值与实验q_e值接近，R²接近1，表明Fe₃O₄@NaX型分子筛对MB的吸附符合拟二级动力学模型.同时，颗粒内扩散动力学模型中的c值不为0，表明颗粒内扩散并不是Fe₃O₄@NaX型分子筛吸附MB速率的唯一控制因素. ...

Removal of basic dye (methylene blue) from aqueous solution using zeolite synthesized from electrolytic manganese residue

2015

... MB adsorption capacities of diﬀerent adsorbents

Table 2

Adsorbents	Time / min	Dosage / g·L^-1	Initial concentration / mg·L^-1	pH value	Temperature / ^oC	Adsorption capacity / mg·g^-1	Ref.
Fe₃O₄@NaX	60	1	50	Natural	25	45.19	This work
WO₃	3	0.05	15	Natural	Natural	1.64	[25]
Zeolite HY-Fe₃O₄ from Zeolite HY and Fe₃O₄	40	1.186	10.23	9	53.9	3.24	[26]
Natural zeolite from Sigmae-Aldrich	120	0.6	20	Natural	25	9.19	[27]
A mixture of zeolite A and P synthesized from electrolytic manganese residue	200	6	200	6	40	33.57	[28]
Zeo-FPT	40	0.5	10	8	25	0.438	[29]
Magnetic graphene oxide	240	0.15	45	9	25	306.5	[30]
Fe₃O₄@UIO-66-NH₂	90	0.004	4	9	Natural	9.53	[31]

2.5 Fe3O4@NaX型分子筛的吸附动力学和吸附模型

将0.1 g的2.0% Fe₃O₄@NaX型分子筛与100 mL的浓度为50 mg/L的MB溶液装入锥形烧瓶中，然后置于不同温度(25、35、45、55和65 ℃)的恒温水浴进行吸附实验，得出不同吸附时间(5、15、30、60、90、120 min)下分子筛对MB的平衡吸附量，采用式(3)~(5)所示的拟一级、拟二级和颗粒内扩散动力学模型公式对上述实验得到的实验数据进行拟合，拟合得到的动力学参数列于表3.从表3可见，用拟二级动力学模型拟合的q_e值与实验q_e值接近，R²接近1，表明Fe₃O₄@NaX型分子筛对MB的吸附符合拟二级动力学模型.同时，颗粒内扩散动力学模型中的c值不为0，表明颗粒内扩散并不是Fe₃O₄@NaX型分子筛吸附MB速率的唯一控制因素. ...

An investigation of a natural biosorbent for removing methylene blue dye from aqueous solution

2023

... MB adsorption capacities of diﬀerent adsorbents

Table 2

Adsorbents	Time / min	Dosage / g·L^-1	Initial concentration / mg·L^-1	pH value	Temperature / ^oC	Adsorption capacity / mg·g^-1	Ref.
Fe₃O₄@NaX	60	1	50	Natural	25	45.19	This work
WO₃	3	0.05	15	Natural	Natural	1.64	[25]
Zeolite HY-Fe₃O₄ from Zeolite HY and Fe₃O₄	40	1.186	10.23	9	53.9	3.24	[26]
Natural zeolite from Sigmae-Aldrich	120	0.6	20	Natural	25	9.19	[27]
A mixture of zeolite A and P synthesized from electrolytic manganese residue	200	6	200	6	40	33.57	[28]
Zeo-FPT	40	0.5	10	8	25	0.438	[29]
Magnetic graphene oxide	240	0.15	45	9	25	306.5	[30]
Fe₃O₄@UIO-66-NH₂	90	0.004	4	9	Natural	9.53	[31]

2.5 Fe3O4@NaX型分子筛的吸附动力学和吸附模型

将0.1 g的2.0% Fe₃O₄@NaX型分子筛与100 mL的浓度为50 mg/L的MB溶液装入锥形烧瓶中，然后置于不同温度(25、35、45、55和65 ℃)的恒温水浴进行吸附实验，得出不同吸附时间(5、15、30、60、90、120 min)下分子筛对MB的平衡吸附量，采用式(3)~(5)所示的拟一级、拟二级和颗粒内扩散动力学模型公式对上述实验得到的实验数据进行拟合，拟合得到的动力学参数列于表3.从表3可见，用拟二级动力学模型拟合的q_e值与实验q_e值接近，R²接近1，表明Fe₃O₄@NaX型分子筛对MB的吸附符合拟二级动力学模型.同时，颗粒内扩散动力学模型中的c值不为0，表明颗粒内扩散并不是Fe₃O₄@NaX型分子筛吸附MB速率的唯一控制因素. ...

Removal of mercury(II) and methylene blue from a wastewater environment with magnetic graphene oxide: adsorption kinetics, isotherms and mechanism

2016

... MB adsorption capacities of diﬀerent adsorbents

Table 2

Adsorbents	Time / min	Dosage / g·L^-1	Initial concentration / mg·L^-1	pH value	Temperature / ^oC	Adsorption capacity / mg·g^-1	Ref.
Fe₃O₄@NaX	60	1	50	Natural	25	45.19	This work
WO₃	3	0.05	15	Natural	Natural	1.64	[25]
Zeolite HY-Fe₃O₄ from Zeolite HY and Fe₃O₄	40	1.186	10.23	9	53.9	3.24	[26]
Natural zeolite from Sigmae-Aldrich	120	0.6	20	Natural	25	9.19	[27]
A mixture of zeolite A and P synthesized from electrolytic manganese residue	200	6	200	6	40	33.57	[28]
Zeo-FPT	40	0.5	10	8	25	0.438	[29]
Magnetic graphene oxide	240	0.15	45	9	25	306.5	[30]
Fe₃O₄@UIO-66-NH₂	90	0.004	4	9	Natural	9.53	[31]

2.5 Fe3O4@NaX型分子筛的吸附动力学和吸附模型

将0.1 g的2.0% Fe₃O₄@NaX型分子筛与100 mL的浓度为50 mg/L的MB溶液装入锥形烧瓶中，然后置于不同温度(25、35、45、55和65 ℃)的恒温水浴进行吸附实验，得出不同吸附时间(5、15、30、60、90、120 min)下分子筛对MB的平衡吸附量，采用式(3)~(5)所示的拟一级、拟二级和颗粒内扩散动力学模型公式对上述实验得到的实验数据进行拟合，拟合得到的动力学参数列于表3.从表3可见，用拟二级动力学模型拟合的q_e值与实验q_e值接近，R²接近1，表明Fe₃O₄@NaX型分子筛对MB的吸附符合拟二级动力学模型.同时，颗粒内扩散动力学模型中的c值不为0，表明颗粒内扩散并不是Fe₃O₄@NaX型分子筛吸附MB速率的唯一控制因素. ...

Fe₃O₄@UiO-66-NH₂ core-shell nanohybrid as stable heterogeneous catalyst for Knoevenagel condensation

2016

... MB adsorption capacities of diﬀerent adsorbents

Table 2

Adsorbents	Time / min	Dosage / g·L^-1	Initial concentration / mg·L^-1	pH value	Temperature / ^oC	Adsorption capacity / mg·g^-1	Ref.
Fe₃O₄@NaX	60	1	50	Natural	25	45.19	This work
WO₃	3	0.05	15	Natural	Natural	1.64	[25]
Zeolite HY-Fe₃O₄ from Zeolite HY and Fe₃O₄	40	1.186	10.23	9	53.9	3.24	[26]
Natural zeolite from Sigmae-Aldrich	120	0.6	20	Natural	25	9.19	[27]
A mixture of zeolite A and P synthesized from electrolytic manganese residue	200	6	200	6	40	33.57	[28]
Zeo-FPT	40	0.5	10	8	25	0.438	[29]
Magnetic graphene oxide	240	0.15	45	9	25	306.5	[30]
Fe₃O₄@UIO-66-NH₂	90	0.004	4	9	Natural	9.53	[31]

2.5 Fe3O4@NaX型分子筛的吸附动力学和吸附模型

将0.1 g的2.0% Fe₃O₄@NaX型分子筛与100 mL的浓度为50 mg/L的MB溶液装入锥形烧瓶中，然后置于不同温度(25、35、45、55和65 ℃)的恒温水浴进行吸附实验，得出不同吸附时间(5、15、30、60、90、120 min)下分子筛对MB的平衡吸附量，采用式(3)~(5)所示的拟一级、拟二级和颗粒内扩散动力学模型公式对上述实验得到的实验数据进行拟合，拟合得到的动力学参数列于表3.从表3可见，用拟二级动力学模型拟合的q_e值与实验q_e值接近，R²接近1，表明Fe₃O₄@NaX型分子筛对MB的吸附符合拟二级动力学模型.同时，颗粒内扩散动力学模型中的c值不为0，表明颗粒内扩散并不是Fe₃O₄@NaX型分子筛吸附MB速率的唯一控制因素. ...

核壳结构Fe₃O₄@UiO-66-NH₂磁性纳米复合材料的合成及其催化Knoevenagel缩合反应性能

2016

... MB adsorption capacities of diﬀerent adsorbents

Table 2

Adsorbents	Time / min	Dosage / g·L^-1	Initial concentration / mg·L^-1	pH value	Temperature / ^oC	Adsorption capacity / mg·g^-1	Ref.
Fe₃O₄@NaX	60	1	50	Natural	25	45.19	This work
WO₃	3	0.05	15	Natural	Natural	1.64	[25]
Zeolite HY-Fe₃O₄ from Zeolite HY and Fe₃O₄	40	1.186	10.23	9	53.9	3.24	[26]
Natural zeolite from Sigmae-Aldrich	120	0.6	20	Natural	25	9.19	[27]
A mixture of zeolite A and P synthesized from electrolytic manganese residue	200	6	200	6	40	33.57	[28]
Zeo-FPT	40	0.5	10	8	25	0.438	[29]
Magnetic graphene oxide	240	0.15	45	9	25	306.5	[30]
Fe₃O₄@UIO-66-NH₂	90	0.004	4	9	Natural	9.53	[31]

2.5 Fe3O4@NaX型分子筛的吸附动力学和吸附模型

将0.1 g的2.0% Fe₃O₄@NaX型分子筛与100 mL的浓度为50 mg/L的MB溶液装入锥形烧瓶中，然后置于不同温度(25、35、45、55和65 ℃)的恒温水浴进行吸附实验，得出不同吸附时间(5、15、30、60、90、120 min)下分子筛对MB的平衡吸附量，采用式(3)~(5)所示的拟一级、拟二级和颗粒内扩散动力学模型公式对上述实验得到的实验数据进行拟合，拟合得到的动力学参数列于表3.从表3可见，用拟二级动力学模型拟合的q_e值与实验q_e值接近，R²接近1，表明Fe₃O₄@NaX型分子筛对MB的吸附符合拟二级动力学模型.同时，颗粒内扩散动力学模型中的c值不为0，表明颗粒内扩散并不是Fe₃O₄@NaX型分子筛吸附MB速率的唯一控制因素. ...

A new absorbent by modifying walnut shell for the removal of anionic dye: kinetic and thermodynamic studies

2014

... 根据在不同温度的吸附实验数据和范特霍夫方程计算出吸附过程的ΔG、ΔH和ΔS，结果列于表5.ΔG < 0表明，Fe₃O₄@NaX型分子筛对MB的吸附属于自发吸附.ΔG随着温度的升高而增大，表明提高温度不利于这种分子筛对MB的吸附.ΔH = -16.3922 kJ/mol和ΔS = -26.1432 J/mol表明，吸附是一个放热的熵减过程^[32]. ...

Comparison of photocatalytic efficiency of supported CuO onto micro and nano particles of zeolite X in photodecolorization of methylene blue and methyl orange aqueous mixture

2014

... 从图11可以看出，吸附前后分子筛的XPS全谱没有明显的变化，吸附后的XPS谱中出现了新的N 1s峰.这表明，MB已经被分子筛吸附.吸附后分子筛中N的结合能(400.4 eV)比纯MB中N的结合能(399.2 ± 0.2) eV稍大，表明MB和分子筛通过N原子发生了相互作用^[33]，促进了分子筛对MB的吸附. ...

Synthesis of Na-X zeolite from Longkou oil shale ash by alkaline fusion hydrothermal method

2018

... 图12给出了分子筛吸附MB前后的FTIR谱.谱中562 cm^-1处的峰归属于Fe-O的振动峰.XPS谱中出现了Na、Si、Al、Fe和O元素的衍射峰，再次确认本文成功地制备出磁性分子筛.同时，1387和1352 cm^-1处出现的MB的C-N伸缩振动峰和CH₃基团的振动峰表明，分子筛能吸附MB^[34]；在3440和1644 cm^-1处的峰归属于O-H和N-H的伸缩振动峰，-OH基团来自分子筛表面和孔道中的水分子，表明Fe₃O₄@NaX型分子筛与MB分子之间形成了氢键，能促进分子筛对MB的吸附. ...

〈

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