Startseite Adsorption performance of hydrophobic/hydrophilic silica aerogel for low concentration organic pollutant in aqueous solution
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Adsorption performance of hydrophobic/hydrophilic silica aerogel for low concentration organic pollutant in aqueous solution

  • Zhigang Yi EMAIL logo , Qiong Tang , Tao Jiang und Ying Cheng
Veröffentlicht/Copyright: 26. November 2019
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Nanotechnology Reviews
Aus der Zeitschrift Nanotechnology Reviews Band 8 Heft 1

Abstract

Hydrophobic silica aerogels (SiO2(AG)) was prepared via sol-gel and solvent exchange method under ambient pressure, which could be transformed to hydrophilic after heated under 500∘C. Heat treatment cannot change its structure. SiO2(AG) samples were the micro-porous structure formed by numerous fine particles and had high specific surface area, pore size and pore volume. The absorption performance of hydrophobic/hydrophilic SiO2(AG) on nitrobenzene, phenol and methylene blue (MB) showed that hydrophobic SiO2(AG) exhibited strong adsorption capacity on slightly soluble organic compounds, while hydrophilic SiO2(AG) was much more effective on adsorbing soluble compounds, which could be analyzed by the hydrophobic and hydrophilic interaction theory between the adsorbent and adsorbate.Hydrophobic/hydrophilic SiO2(AG) adsorption performance for MB is superior to that for phenol, which could be explained via the electrostatic interaction theory.

Keywords: Silica aerogels; Adsorbent; Organic pollutant

1 Introduction

In the last decades, with the rapid development of industry, large amounts organic compounds were widely used in different field, such as pesticides, dyes, synthetic rubber, plastics. The large-scale use of chemical raw materials has led to a series of environmental pollution. Many organic pollutants with the feature of bioaccumulation and difficulty biochemical degradation, can present high risk to ecosystem and human health even at low concentration [1, 2]. The prevention and removal organic contaminations in aquatic environment has attracted great attention. Conventional methods like adsorption [3, 4], biodegradation [5], advanced oxidation processes [6, 7, 8, 9], etc. have been in-depth investigated and widely used. Compared with other ways,adsorption process is the most commonly technology to remove organic pollutants from water due to its simplicity, high efficiency [3, 4]. In general, the adsorption property of adsorbents is determined by the morphology and structure of porous materials, such as specific surface areas, pore volumes, pore distributions and special pore surface chemistries [10]. Thus, the porous materials with special size and properties, such as graphene, carbon aerogels, activated carbon, polymers, porous silica, and metal-organic frameworks are actively investigated as advanced sorbents [11, 12, 13, 14, 15, 16]. Among them, activated carbon is a widely used adsorbent due to its availability and high adsorption capacity [17]. However, carbons display disadvantages such as limited modification flexibility and low selectivity, which limit their applications [18].

As an unique material with wide application [19, 20], silica aerogel (SiO2(AG)) is a three-dimensional and multi-scaled porous nano-material formed by numerous fine particles and networks. Traditional preparation of SiO2(AG) involve two different ways: the process of supercritical drying and ambient pressure drying (APD) technique. The method of supercritical drying can avoid capillary stress and associated drying shrinkage. However, this process is energy intensive and can be dangerous, which leads to high costs and results in limited practical applications [21, 22]. APD technique could overcome the disadvantages of supercritical aerogel process, and made the manufacture and application of SiO2(AG) in large scale possible [23, 24, 25]. The SiO2(AG) has been increasingly researched as an adsorbent owing to its high porosity (up to 99%), high specific surface area, low density, and ease of surface modification, etc. [26, 27, 28, 29]. Hrubesh et al. [28] prepared hydrophobic SiO2(AG) via the supercritical drying method, and proceeded the adsorption experiments of decomposing different organic compounds in water. The results showed that the adsorption capacity of the hydrophobic SiO2(AG) was 30 times as that of the carbon for the soluble organic compounds, and up to 130 times for the insoluble organic compounds. Reynolds et al. [29] carried out adsorption experiments about hydrophobic SiO2(AG) to the oil slick in water, and the results indicated that the capacity of the oil absorption into the hydrophobic SiO2(AG) was up to 273 times as its own volume. Perdigoto et al. [30] got SiO2(AG) from methyltrimethoxysilane (MTMS) as a precursor by supercritical drying, and adsorption capacities of SiO2(AG) were shown to uptake more than 50 mg/g of benzene at 50 mg/L of benzene solution. Wang et al. [31] prepared hydrophobic SiO2(AG) and tested its adsorption for organic compounds from aqueous phase. Adsorption equilibrium of SiO2(AG) was reached in under 20 min and the adsorption capacities were 223 mg/g for toluene and 87 mg/g for benzene.

Previous researches suggested that the adsorption capacity of adsorbent was primarily decided by the pore structure and surface area, the surface chemical properties were also important, furthermore, the hydrophobicity, polarity, electron accepting or donating property and the structure of the pollutants could also affect the adsorption affinity [32]. However, the results discussed in many studies on adsorption performance of SiO2(AG) has focused on hydrophobic media. Investigation on other factors of adsorption property and adsorption mechanisms were still fragmentary.

In this work, in order to give a fundamental knowledge for potential application of SiO2(AG) on pollutants removal. Hydrophobic/hydrophilic SiO2(AG) were prepared via the APD route, and to compare different adsorption performance for nitrobenzene, phenol and methylene blue (MB) with different physicochemical properties, which were common pollutants in industrial wastewater. The adsorption isotherm were evaluated, and the adsorption mechanisms were also discussed.

2 Experimental

2.1 Materials

Tetraethyl orthosilicate (TEOS), anhydrous ethanol (EtOH), hexane (C6H14), trimethylchlorosilane (TMCS), hydrochloric acid (HCl), ammonia water (NH3·H2O), nitrobenzene (C6H5NO2), phenol (C6H5OH) and methylene blue (MB) were analytical grade and commercially purchased from Chron Chemicals Co., Ltd., Chengdu. All reagents were used without any further purification. Deionized water made from laboratory, was used in all experiments.

2.2 Preparation of SiO2(AG)

Based on the sol-gel method, hydrophobic SiO2(AG) was synthesized by controlling the solvent exchanging procedure under ambient pressure. A certain proportion of TEOS, EtOH, and deionized water (mole ratios of TEOS/EtOH/water=1:3:6) were put into a 200 mL beaker, dropping 0.1 mol/L HCl in order to control the pH of the solution in the rage of 2.0-3.0. After stirring for 60 min, 0.1 mol/L NH3·H2O solution was added to the silica sol to adjust the pH in the rage of 5.0-6.0, until wet gels were gotten. The obtained wet gels were collected and aged for 24 h at room temperature, followed a soaking process in EtOH(50%) for 24 h, then soaked in a mixed solvent with volume ratio of EtOH/TMCS/hexane=1:0.8:1 for 48 h. After filtrating, the wet gels were washed 3 times by hexane and dried 60∘C for 24 h, to obtain the hydrophobic SiO2(AG). The hydrophilic SiO2(AG) was gotten by above processes and calcination at 500∘C for 3h [10].

2.3 Characterization

The microstructure of fabricated materials was investigated bySEM(Inspect F,FEI,Holland) andTEM(JEM-2100F, JEOL, Japan). X-ray diffraction (XRD DX-2500) was used to analyzed the crystal structure, the X-ray target made of Cu Kα-ray generator (40 kV, 40 mA, λ = 0.15406 nm).The pore structure and specific surface area (SSA) of the materials were respectively determined by the automatic surface area and porosity analyzer (3H-2000PS4, Beishide instrument Technology Co., Ltd., Beijing), the test conditions of automatic surface area and porosity analyzer were: nitrogen as adsorbate, degassing mode of heating-vacuum, degassing temperature of 150∘C, degassing time of 180 min, saturated steam pressure of 1.0434 bar, ambient temperature of 14.0∘C. The surface functional groups of materials were characterized by the FTIR spectra of the materials by using the Fourier transform infrared spectrometer (Nicolet 5700 Spectrophotometer, FTIR), the samples were performed by pressing the power mixed with some of KBr into disks, and the scanning wave number range was set to 4000~ 400 cm−1. The hydrophobic properties of the materials were obtained by measuring contact angle of water droplets and materials using a contact angle meter (DSA100, KRUSS, Germany).

2.4 Research of adsorption performance

The adsorption experiments were conducted in three different organic solution (nitrobenzene, phenol and methylene blue (MB) solution, respectively). 250 ml conical flask containing 100 ml organic solution and 2 g/l adsorbent (hydrophobic/hydrophilic SiO2(AG)) were shaken at 220 r/min. Temperature was kept at 25∘C. Adsorption capacity of SiO2(AG) was reflected by measuring the change of concentration of organic compounds, which were determined by UV-vis spectrophotometer (UV-2550, Shimadzu, Japan).

The adsorption amount of organic compounds on adsorbent is calculated as:

(1)q=c0−ce×vw

Where q is the adsorption amount of organic compounds on adsorbent, mg/g; C0 is the initial concentration of organic compounds in solution, mg/l; Ce is the equilibrium adsorption concentration of organic compounds in solution after adsorption equilibrium, mg/l; v is the volume of solution, l; w is the dosage of adsorbent, g.

Langmuir isotherm adsorption model and Freundlich isotherm adsorption model were usually to fit the adsorption behavior of the organic compounds in dilute solution [33].

2.4.1 Langmuir isothermal adsorption model

Langmuir isothermal adsorption model used to describe the adsorption behavior in the solid-liquid system, expressed by equation 2 or 3 [34]:

(2)q=qmkLCe1+kLCe
(3)1q=1qm+1kLqm⋅1Ce

Where Ce is the equilibrium concentration in solution, mg/l; q is the adsorption amount in the adsorbent, mg/g; qm is the saturated adsorption amount in the adsorbent, mg/g; kL is the Langmuir adsorption constant, l/mg, reflects the affinity between the adsorbate and the adsorption sites.

2.4.2 Freundlich isothermal adsorption model

Freundlich isothermal adsorption model is an empirical equation, which describes the adsorption equilibrium in the solid-liquid adsorption process, that adsorption heat decreased logarithmically with the increases of adsorption amount under isothermal conditions. the model takes uneven surface into account, expressed by equation 4 or 5 [34]:

(4)q=KFCe1n
(5)ln⁡q=lnKF+1nlnCe

Where Ce is the equilibrium concentration in solution, mg/l; q is the adsorption amount on the adsorbent, mg/g; KF is the Freundlich adsorption constant, which is a measure of the adsorption capacity, the greater of its value, then the bigger of the adsorption amount; n is a constant and usually greater than 1, and its inverse is a measure of the adsorption intensity.

3 Results and discussion

3.1 Morphology of SiO2(AG)

Morphologies of hydrophobic/hydrophilic SiO2(AG) samples were investigated by SEM and TEM. As shown in Figure 1(a), the hydrophobic SiO2(AG) samples prepared under ambient pressure presented a spongy-liked shape, which were made of numerous fine particles and formed a loose and porous structure, and uniform particle size distribution. Hydrophilic SiO2(AG) was gained via hydrophobic SiO2(AG) calcined 3h under 500∘C, Figure 1(b) indicated its surface appearance had no significant difference from hydrophobic SiO2(AG).

Figure 1 SEM image of SiO2(AG) sample (a: hydrophobic; b: hydrophilic) (insets are TEM images)
Figure 1

SEM image of SiO2(AG) sample (a: hydrophobic; b: hydrophilic) (insets are TEM images)

3.2 Specific surface area and pore structure of SiO2(AG)

The textural properties of SiO2(AG) were analyzed by using Nitrogen adsorption-desorption method. As can be seen in Figure 2, the N2 adsorption-desorption isotherms of hydrophobic/hydrophilic SiO2(AG) samples were a typical type IV adsorption isotherms characteristic with an adsorption hysteresis, indicated that the nano-porous structure exists on hydrophobic/hydrophilic SiO2(AG), and the hole shape was the narrow tubular pores of the ends open and mouth width [10]; The SSA was determined by using BET (Brunauer-Emmett-Teller) method. Pore size distribution and total pore volume of the materials were evaluated from the adsorption branch of nitrogen isotherms by using the BJH (Barrett-Joyner-Halenda) method. The insets of Figure 2 displayed the BJH differential integral hole volume and pore size distribution curve of SiO2(AG).

Figure 2 N2 adsorption-desorption isotherm of SiO2(AG) (a: hydrophobic; b:hydrophilic) (insets are BJH differential integral hole volume and pore size distribution curve of SiO2(AG))
Figure 2

N2 adsorption-desorption isotherm of SiO2(AG) (a: hydrophobic; b:hydrophilic) (insets are BJH differential integral hole volume and pore size distribution curve of SiO2(AG))

The experimental results on the SSA, pore size and total pore volume of the SiO2(AG) powders have been compiled in Table 1. The results showed that hydrophobic/hydrophilic SiO2(AG) samples had high specific surface area, pore size and pore volume. The conclusions were consistent with the characterization results by TEM. The reason for the decrease in pore size and volume of hydrophilic SiO2(AG) might be the shrinkage and collapse during the calcination process.

Table 1

SSA, pore size and pore volume of hydrophobic/hydrophilic SiO2(AG)

SampleSSA(m2/g)pore size (nm)pore volume (mL/g)
hydrophobic SiO2(AG)9028.912.0094
hydrophilic SiO2(AG)9285.821.4085

3.3 The FT-IR analysis of SiO2(AG)

The FT-IR spectrum of hydrophobic/hydrophilic SiO2(AG) were shown in Figure 3. The adsorption peaks at around 3490 cm−1 of hydrophobic SiO2(AG) was significantly weaker than hydrophilic SiO2(AG), it was due to that the –OH group on the surface of SiO2(AG) was replaced by the organic group in the process of modification. As shown in FT-IR spectrum of hydrophobic SiO2(AG), the characteristic peaks at 2968 cm−1 corresponding to the C-H of -CH3 antisymmetric stretching vibration, 1387 cm−1 and 928 cm−1 appeared the symmetric vibration and in-plane vibration of –CH3 group respectively, which indicated – CH3 to existed on the surface of hydrophobic SiO2(AG). In addition, the peak at 758 cm−1 corresponding to the symmetric stretching vibration of Si-CH3, suggested that Si-CH3 group was contained on the surface of hydrophobic SiO2(AG). Analyzing by FT-IR, the hydrophobic -CH3 connected with branched chain of SiO2(AG) that prepared by solvent exchange method, which let it has hydrophobic properties. The FT-IR of hydrophilic SiO2(AG) showed the peaks of –OH group existed on the surface of hydrophilic SiO2(AG), which let it has hydrophilic performance, it was due to that –CH3 group on the surface of hydrophobic SiO2(AG) has been translated into –OH group after calcination at 500∘C [10].

Figure 3 FTIR spectra of hydrophobic/ hydrophilic SiO2(AG)
Figure 3

FTIR spectra of hydrophobic/ hydrophilic SiO2(AG)

3.4 Contact angle of SiO2(AG)

The hydrophobicity of SiO2(AG) was measured by testing the contact angle of SiO2(AG), the results were displayed in Figure 4. The prepared hydrophobic SiO2(AG) had a good hydrophobicity, 500∘C heat treatment promoted the conversion from hydrophobicity to hydrophilicity. The conclusions were consistent with the characterization results by FT-IR.

Figure 4 Contact angle of SiO2(AG) of SiO2(AG) (a: hydrophobic; b:hydrophilic)
Figure 4

Contact angle of SiO2(AG) of SiO2(AG) (a: hydrophobic; b:hydrophilic)

3.5 Adsorption property of hydrophobic/hydrophilic SiO2(AG)

3.5.1 Adsorption curves of different organic compounds

The adsorption experiments were carried out in 100 ml nitrobenzene solution(12 mg/l), phenol solution(10 mg/l) and MB solution(10 mg/l) respectively. The dosage of hydrophobic/hydrophilic SiO2(AG) was 2.0 g/l. As shown in the adsorption curves of hydrophobic SiO2(AG) on different adsorbate, Figure 5(a), the hydrophobic SiO2(AG) exhibited the best adsorption capacity of by removing 51.8% nitrobenzene within 1 h when the system reached adsorption equilibrium, on the other hand, it exhibited poor adsorption capacity on phenol and MB by adsorbing only 9.9% and 17.6%, respectively, and did not get adsorption equilibrium even after 10 h. Figure 5(b) displayed adsorption property of hydrophilic SiO2(AG), the removal ratio of phenol and MB by adsorption of hydrophilic SiO2(AG) was 57.8% and 64.3% respectively, and reached adsorption equilibrium within 0.5 h. On the contrary, it showed poor adsorption performance on nitrobenzene by adsorbing only 17.8% and got adsorption equilibrium in 1.5 h.

Figure 5 Adsorption curves of nitrobenzene, phenol and MB by SiO2(AG)
Figure 5

Adsorption curves of nitrobenzene, phenol and MB by SiO2(AG)

3.5.2 Adsorption isotherms

Isothermal adsorption experiment were conducted in nitrobenzene solution (12,24,36,48,60 mg/l), phenol solution (10,20,30,40,50 mg/l) and methylene blue (MB) solution (10,20,30,40,50mg/l), respectively. The liquid adsorption isotherms of hydrophobic/hydrophilic SiO2(AG) on organic solution, and fitted curves by Langmuir and Freundlich isotherm models were shown in Figure 6(a)-6(c) and Figure 6(d)-6(f), respectively. The results indicated that the equilibrium adsorption amount of hydrophobic/hydrophilic SiO2(AG) increased with the increase of equilibrium concentration of organic compounds. In the range of the concentration in this experiment, the equilibrium adsorption amount of hydrophobic SiO2(AG) for nitrobenzene was 6.32 mg/g, while for phenol and MB was 1.19 mg/g and 2.63 mg/g, respectively; but the equilibrium adsorption amount of hydrophilic SiO2(AG) for nitrobenzene is only 2.38 mg/g, obviously lower than the equilibrium adsorption amount of hydrophobic SiO2(AG) for nitrobenzene, while for phenol and MB reached 6.40 mg/g and 8.32 mg/g respectively, significantly higher than the equilibrium adsorption amount of hydrophobic SiO2(AG).

Figure 6 Adsorption isotherm and fitting curves of nitrobenzene, phenol and MB by SiO2(AG) (a), (b), (c) and (d), (e), (f): Adsorption isotherm, Langmuir fitting curves and Freundlich fitting curves of hydrophobic SiO2(AG) and hydrophilic SiO2(AG), respectively
Figure 6

Adsorption isotherm and fitting curves of nitrobenzene, phenol and MB by SiO2(AG) (a), (b), (c) and (d), (e), (f): Adsorption isotherm, Langmuir fitting curves and Freundlich fitting curves of hydrophobic SiO2(AG) and hydrophilic SiO2(AG), respectively

The relevant parameters of Langmuir and Freundlich isotherm models were displayed in Table 2. The results showed that Langmuir and Freundlich isotherm models could fit well the adsorption isotherms of SiO2(AG) for nitrobenzene, phenol and methylene blue. Related studies [34] suggested that Freundlich constant KF was a constant related to the adsorption capacity, the greater KF would course greater adsorption; when the value of constant 1/n was in the range from 0.1 to 0.5, the adsorbate was easily absorbed, and the value was smaller, the adsorption properties were better; with the increases of 1/n,while the equilibrium concentration of the adsorbate was higher, the absorption capacity would play more sufficient. Compared with the relevant parameters from Table 2, adsorption performance of hydrophobic SiO2(AG) for nitrobenzene was much better than that for phenol and MB; while the hydrophilic SiO2(AG) expressed a better adsorption property for phenol and MB;Both the hydrophobic and hydrophilic SiO2(AG), its adsorption properties for MB were superior to that for phenol.

Table 2

Isothermal adsorption fitting results of nitrobenzene, phenol and MB by SiO2(AG)

adsorbentadsorbateLangmuir equationFreundlich equation
qmKLR2KFnR2
hydrophobic

SiO2(AG)		nitrobenzene6.96860.14150.98661.86213.12210.9904
phenol1.73220.04540.99580.16311.89750.9969
MB4.64680.02860.99760.24361.58160.9833
hydrophilic

SiO2(AG)		nitrobenzene3.05060.05570.98620.39532.21480.9927
phenol6.93480.17180.95911.77362.76010.9973
MB9.53290.14490.99541.98832.39810.9910

3.5.3 Adsorption mechanism research

In the organic compounds adsorption process in solution, the adsorbent surface area, pore size distribution, pore structure and other characteristics of material plays a decisive role to its adsorption properties [35]. In addition, adsorbents exhibit differences of adsorption performance to different adsorbates, which could be analyzed by the hydrophobic and hydrophilic interaction theory between the adsorbent and adsorbate, molecular polarity theory, electrostatic interaction theory, the electron donor-acceptor interaction theory, π-π dispersion theory [36, 37]. According to the hydrophobic and hydrophilic interaction theory in water phase, the hydrophobicity of SiO2(AG) plays a leading role in the organic compounds adsorption process. Nitrobenzene is an insoluble hydrophobic organic compounds, MB and phenol are hydrophilic organic compounds and freely soluble in water, and the hydrophilic SiO2(AG) is infiltrated easily by water molecules which occupy a part of pores. So, the hydrophobic SiO2(AG) shows better adsorption to nitrobenzene than other one; hydrophilic SiO2(AG) has better adsorption to MB and phenol. Hydrophobic and hydrophilic SiO2(AG) adsorption performance for MB is superior to that for phenol, basing on the electrostatic interaction theory, SiO2 isoelectric point is very low [38], less than the pH of the phenol and MB solution, SiO2(AG) in phenol and MB solution will show electro-negativity, MB is a typical cationic dye with a positive charge, while phenol is electrically neutral. So there exist an electrostatic attraction between MB and SiO2(AG), and the adsorption performance of SiO2(AG) for MB prove better than phenol.

4 Conclusion

Via sol-gel and solvent exchange method, hydrophobic SiO2(AG) was prepared under ambient pressure, and it could be transformed to hydrophilic after 500∘C heat treatment. The results of material characterization showed that the synthesized hydrophobic/hydrophilic SiO2(AG) were the micro-porous structure formed by numerous fine particles and had high specific surface area, pore size and pore volume.

The absorption experiments of hydrophobic/hydrophilic SiO2(AG) for nitrobenzene, phenol and MB showed that hydrophobic/hydrophilic SiO2(AG) was effective in removing organic compounds from aqueous solution. Hydrophobic SiO2(AG) showed much stronger adsorption effectiveness on slightly soluble organic compounds, while hydrophilic SiO2(AG) was much more effective on adsorbing soluble compounds, which could be analyzed by the hydrophobic and hydrophilic interaction theory between the adsorbent and adsorbate. Adsorption performance of hydrophobic/hydrophilic SiO2(AG) for MB is superior to that for phenol, which could be explained via the electrostatic interaction theory.

Due to the high adsorption efficiency on a wide range of organic pollutant in water, easy modification of the properties, and the relative low manufacture cost, hydrophobic/hydrophilic SiO2(AG) has great application potential in the wastewater treatment field.

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Acknowledgement

This work was supported by the National Natural Science Foundation of China (No. 21507052), Project of Introduction of teachers of Leshan Normal University, Sichuan Province, China (Grant No.Z1517) and Scientific Research Fundation of Leshan Science & Technology Bereau, Sichuan Province, China (Grant No. 15ZDYJ0144).

  1. Data accessibility We have conducted our experiment systematically and reported their experimental procedure clearly in the experimental section and provided all necessary data in results and discussion section in the main manuscript.

  2. Author Contributions: Zhigang Yi designed, supervised experiments and led the drafting of manuscript. Qiong Tang and Tao Jiang assisted in the analysis and testing work during the experiments. Ying Cheng contributed to characterization of property of material.

  3. Conflict of Interest

    Conflict of Interests: There is no conflict of interest regarding the publication of this paper.

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Received: 2019-04-14
Accepted: 2019-05-14
Published Online: 2019-11-26

© 2019 Z. Yi et al., published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 Public License.

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  2. Investigation of rare earth upconversion fluorescent nanoparticles in biomedical field
  3. Carbon Nanotubes Coated Paper as Current Collectors for Secondary Li-ion Batteries
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  9. Fractal analysis of pore structures in graphene oxide-carbon nanotube based cementitious pastes under different ultrasonication
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  11. Cr effects on the electrical contact properties of the Al2O3-Cu/15W composites
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  13. Experimental study on the existence of nano-scale pores and the evolution of organic matter in organic-rich shale
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  16. Fabrication, mechanical properties and failure mechanism of random and aligned nanofiber membrane with different parameters
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  18. First-principles calculations of mechanical and thermodynamic properties of tungsten-based alloy
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  20. Preparation of spherical aminopropyl-functionalized MCM-41 and its application in removal of Pb(II) ion from aqueous solution
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  46. Mechanical contribution of vascular smooth muscle cells in the tunica media of artery
  47. Applications of polymer-based nanoparticles in vaccine field
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https://doi.org/10.1515/ntrev-2019-0025
Schlagwörter für diesen Artikel
Silica aerogels; Adsorbent; Organic pollutant
Creative Commons
BY 4.0

Artikel in diesem Heft

  1. Research Articles
  2. Investigation of rare earth upconversion fluorescent nanoparticles in biomedical field
  3. Carbon Nanotubes Coated Paper as Current Collectors for Secondary Li-ion Batteries
  4. Insight into the working wavelength of hotspot effects generated by popular nanostructures
  5. Novel Lead-free biocompatible piezoelectric Hydroxyapatite (HA) – BCZT (Ba0.85Ca0.15Zr0.1Ti0.9O3) nanocrystal composites for bone regeneration
  6. Effect of defects on the motion of carbon nanotube thermal actuator
  7. Dynamic mechanical behavior of nano-ZnO reinforced dental composite
  8. Fabrication of Ag Np-coated wetlace nonwoven fabric based on amino-terminated hyperbranched polymer
  9. Fractal analysis of pore structures in graphene oxide-carbon nanotube based cementitious pastes under different ultrasonication
  10. Effect of PVA fiber on durability of cementitious composite containing nano-SiO2
  11. Cr effects on the electrical contact properties of the Al2O3-Cu/15W composites
  12. Experimental evaluation of self-expandable metallic tracheobronchial stents
  13. Experimental study on the existence of nano-scale pores and the evolution of organic matter in organic-rich shale
  14. Mechanical characterizations of braided composite stents made of helical polyethylene terephthalate strips and NiTi wires
  15. Mechanical properties of boron nitride sheet with randomly distributed vacancy defects
  16. Fabrication, mechanical properties and failure mechanism of random and aligned nanofiber membrane with different parameters
  17. Micro- structure and rheological properties of graphene oxide rubber asphalt
  18. First-principles calculations of mechanical and thermodynamic properties of tungsten-based alloy
  19. Adsorption performance of hydrophobic/hydrophilic silica aerogel for low concentration organic pollutant in aqueous solution
  20. Preparation of spherical aminopropyl-functionalized MCM-41 and its application in removal of Pb(II) ion from aqueous solution
  21. Electrical conductivity anisotropy of copper matrix composites reinforced with SiC whiskers
  22. Miniature on-fiber extrinsic Fabry-Perot interferometric vibration sensors based on micro-cantilever beam
  23. Electric-field assisted growth and mechanical bactericidal performance of ZnO nanoarrays with gradient morphologies
  24. Flexural behavior and mechanical model of aluminum alloy mortise-and-tenon T-joints for electric vehicle
  25. Synthesis of nano zirconium oxide and its application in dentistry
  26. Surface modification of nano-sized carbon black for reinforcement of rubber
  27. Temperature-dependent negative Poisson’s ratio of monolayer graphene: Prediction from molecular dynamics simulations
  28. Finite element nonlinear transient modelling of carbon nanotubes reinforced fiber/polymer composite spherical shells with a cutout
  29. Preparation of low-permittivity K2O–B2O3–SiO2–Al2O3 composites without the addition of glass
  30. Large amplitude vibration of doubly curved FG-GRC laminated panels in thermal environments
  31. Enhanced flexural properties of aramid fiber/epoxy composites by graphene oxide
  32. Correlation between electrochemical performance degradation and catalyst structural parameters on polymer electrolyte membrane fuel cell
  33. Materials characterization of advanced fillers for composites engineering applications
  34. Humic acid assisted stabilization of dispersed single-walled carbon nanotubes in cementitious composites
  35. Test on axial compression performance of nano-silica concrete-filled angle steel reinforced GFRP tubular column
  36. Multi-scale modeling of the lamellar unit of arterial media
  37. The multiscale enhancement of mechanical properties of 3D MWK composites via poly(oxypropylene) diamines and GO nanoparticles
  38. Mechanical properties of circular nano-silica concrete filled stainless steel tube stub columns after being exposed to freezing and thawing
  39. Arc erosion behavior of TiB2/Cu composites with single-scale and dual-scale TiB2 particles
  40. Yb3+-containing chitosan hydrogels induce B-16 melanoma cell anoikis via a Fak-dependent pathway
  41. Template-free synthesis of Se-nanorods-rGO nanocomposite for application in supercapacitors
  42. Effect of graphene oxide on chloride penetration resistance of recycled concrete
  43. Bending resistance of PVA fiber reinforced cementitious composites containing nano-SiO2
  44. Review Articles
  45. Recent development of Supercapacitor Electrode Based on Carbon Materials
  46. Mechanical contribution of vascular smooth muscle cells in the tunica media of artery
  47. Applications of polymer-based nanoparticles in vaccine field
  48. Toxicity of metallic nanoparticles in the central nervous system
  49. Parameter control and concentration analysis of graphene colloids prepared by electric spark discharge method
  50. A critique on multi-jet electrospinning: State of the art and future outlook
  51. Electrospun cellulose acetate nanofibers and Au@AgNPs for antimicrobial activity - A mini review
  52. Recent progress in supercapacitors based on the advanced carbon electrodes
  53. Recent progress in shape memory polymer composites: methods, properties, applications and prospects
  54. In situ capabilities of Small Angle X-ray Scattering
  55. Review of nano-phase effects in high strength and conductivity copper alloys
  56. Progress and challenges in p-type oxide-based thin film transistors
  57. Advanced materials for flexible solar cell applications
  58. Phenylboronic acid-decorated polymeric nanomaterials for advanced bio-application
  59. The effect of nano-SiO2 on concrete properties: a review
  60. A brief review for fluorinated carbon: synthesis, properties and applications
  61. A review on the mechanical properties for thin film and block structure characterised by using nanoscratch test
  62. Cotton fibres functionalized with plasmonic nanoparticles to promote the destruction of harmful molecules: an overview
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