- Email: [email protected]
Preparation of Ganoderma lucidum polysaccharide‑chromium (III) complex and its hypoglycemic and hypolipidemic activities in high-fat and high-fructose diet-induced pre-diabetic mice
Article Cite This: Ind. Eng. Chem. Res. 2019, 58, 8044−8049
pubs.acs.org/IECR
Durability and Stability of Superhydrophobic Stainless Steel Mesh Supported Pure-Silica Zeolite Beta Coatings Yun Li, Xiufeng Liu, and Baoquan Zhang* State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China
Downloaded via UNIV OF GOTHENBURG on October 22, 2019 at 14:32:19 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.
S Supporting Information *
ABSTRACT: The poor durability and stability of superhydrophobic materials under various working conditions limit their widespread applications. Zeolite films have attracted considerable attention owing to their good mechanical, thermal, and chemical stabilities. Stainless steel mesh (SSM) supported pure-silica zeolite beta (PSZB) coatings with superhydrophobicity were fabricated using secondary growth method. The durability and stability of SSM-supported PSZB coatings were investigated thoroughly after undergoing various treatments, including abrasion, corrosion, high temperature, and ultrasonication. The SSM-supported PSZB coatings could maintain their superhydrophobicity and high separation efficiencies above 99% with trace amount of oil contents in water as well as stable chloroform fluxes after abrasion for 80 cycles or exposure to corrosive media. The PSZB coating could keep a close attachment on the SSM support in hightemperature and ultrasonication environments. This work demonstrated the satisfactory durability and stability of SSMsupported PSZB coatings and gives promise for zeolite-coated SSMs in actual oil/water separation. wettability.19 Guo et al. fabricated the silicalite-1 film on SSM with both superamphiphilicity in air and superoleophobicity underwater.20 In our previous work, the SSM-supported puresilica zeolite beta (PSZB) coating was prepared by using the seeded-growth method.21 The rough hierarchical structure on the outer surface of synthesized SSM-supported PSZB coatings together with intrinsic hydrophobicity of PSZB give both superhydrophobicity and superoleophilicity. It was demonstrated that the SSM-supported PSZB coating exhibited high separation efficiencies for oil/water mixtures.21 However, the durability and stability of these materials have not been checked systematically when exposed to rigorous operation conditions, including high temperature, strong corrosive media, and mechanical damages. With respect to superhydrophobic SSM-supported PSZB coatings, the changes in both surface morphology and separation performances were evaluated by way of abrasion, corrosion, heating, and sonication in this contribution. It is demonstrated that the SSM-supported PSZB coatings possess satisfactory mechanical durability, corrosion resistance, and thermal stability. They could retain superhydrophobic characteristics and high separation performances after various treatments.
1. INTRODUCTION Superwettable materials have been widely used in the field of oil/water separation,1,2 unidirectional liquid penetration,3 and other smart applications.4,5 Of reported superwettable materials, stainless steel mesh (SSM)-based materials with superhydrophobicity have drawn much attention to oil/water separation owing to their satisfactory performances and ease of operation.6 Polymers and inorganic substances have been employed to modify SSMs by spraying,7,8 thermal polymerization,9 combustion,10 vacuum suction,11 stacking,12 and hydrothermal crystallization.13 Although these materials exhibit high separation performances for a variety of oil/water mixtures, most of them would lose their superhydrophobicity when immersed in corrosive media or exposed to hightemperature environments or suffer mechanical damages as a result of the destruction of micro/nanoscale hierarchical structures and/or low-energy surface, eventually hindering development of their actual applications.14 Zeolites show excellent mechanical, thermal, and chemical stabilities due to their dense crystalline backbone.15−17 Thus, it is desirable to fabricate robust zeolite films with special wetting ability for actual oil/water separation. Currently, there are only a few reports about SSM supported zeolite coatings with superwettability. Yu et al. designed the silicalite-1 coated SSM with superhydrophilicity and underwater superoleophobicity to separate water from oil.18 Kim et al. prepared the MFI-type zeolite-coated SSM using in situ crystallization method and studied the effect of Al/Si ratio on the membrane surface © 2019 American Chemical Society
Received: Revised: Accepted: Published: 8044
January 3, 2019 April 5, 2019 April 24, 2019 April 24, 2019 DOI: 10.1021/acs.iecr.9b00046 Ind. Eng. Chem. Res. 2019, 58, 8044−8049
Article
Industrial & Engineering Chemistry Research
flushed with N2. The high-temperature treatment was carried out to demonstrate the thermal stability of SSM-supported PSZB coatings. The sample was heated to a set temperature and kept there for 1 h, and the sample cooled at last. The ultrasonication treatment was employed to check the adhesive strength of the superhydrophobic coating on the support. Samples were subjected to sonication with 200 W in chloroform solvent for a specific time period. The samples after ultrasonication treatment were washed by ethanol and flushed with N2. The surface wettability of all treated samples was estimated according to the static water contact angle (WCA) measurement. The oil/water separation of treated SSM-supported PSZB coatings was also carried out to illustrate the effect of various treatments on separation performances. 2.3. Characterization. The morphologies of SSMsupported PSZB coatings were obtained via scanning electron microscopy (SEM, Hitachi S-4800). The surface wettability of SSM-supported PSZB coatings was measured by static WCAs (Dataphysics OCAH 200) with the drop size of ∼3 μL. The final value was reported as the mean of three experiments. 2.4. Oil/Water Separation. The oil/water separation was conducted as reported previously.21 Chloroform permeated through the SSM-supported PSZB coating, while water was intercepted. The separation efficiency was defined according to η% = (m1/m0) × 100, for which m0 is the mass of water before the separation process and m1 the mass of water intercepted in the upper tube.10 The residual oil content in water was measured by using a Ke-Chuang 9800 gas chromatograph equipped with a thermal conductivity detector. In addition, the chloroform flux was measured to describe the separation performance of the SSM-supported PSZB coatings.21 The setup was the same as the above separation system. Chloroform was poured, and the liquid level was maintained at the height of 10 cm. The volume (V) of permeated chloroform was recorded. The flux (F) was calculated according to F = V/(S × t), where S is the film area and t the permeation time.21 The final result was taken from three repeated experiments.
2. EXPERIMENTAL SECTION 2.1. Synthesis of SSM-Supported PSZB Coatings. The detailed descriptions about materials and chemical reagents used in this experiment are available in the Supporting Information. The SSM-supported PSZB coating was prepared by secondary growth method as reported previously.21 First, the polydopamine modified method was employed to prepare seed layers on the surface of SSMs with high coverage degree. The dealuminated zeolite beta seeds were redispersed into freshly prepared Tris(hydroxy-methyl) aminomethane (Tris) buffer solution to form a 0.5 wt % suspension. The preprepared SSM (350 mesh, 3 × 3 cm) was immersed into the seed suspension with dopamine (DA) for 20 h and dried at 60 °C. Then, the seeded SSM was treated in a synthesis gel with a molar composition of tetraethylammonium hydroxide (TEAOH):SiO2:hydrofluoric acid (HF):H2O:n-propanol = 0.6:1.0:0.6:7:2.4. The fumed silica was dissolved in TEAOH solution at 80 °C under vigorous stirring. HF was added to the obtained synthesis gel, resulting in the formation of light yellow solid. Then, to the above solid, n-propanol was added with stirring, forming a homogeneous gel. After being aged for 24 h, the resultant gel was transferred to a Teflon-lined autoclave, where the seeded substrate was placed vertically. The hydrothermal treatment was carried out at 140 °C for 7 d. The as-synthesized samples were cleaned by deionized water (DI H2O) and dried with nitrogen (N2) purging. 2.2. Postsynthetic Treatments. The abrasion on the SSM-supported PSZB coating was performed to investigate its mechanical durability. As shown in Figure 1, a sample was
Figure 1. Abrasion treatment of the SSM-supported PSZB coating on sandpaper.
moved 10 cm on a piece of sandpaper (2000 mesh) at a speed of 5 cm s−1 under a load weighing of 25 g for a number of repeated cycles.22 To investigate the chemical stability of the PSZB coating, samples were subjected to corrosion in 0.1 M HCl, 0.1 M NaOH, and 1 M NaCl for 24 h. After immersion, the samples were washed with DI H2O and ethanol and then
3. RESULTS AND DISCUSSION For actual applications, it is vital that superhydrophobic materials maintain their micro/nanoscale hierarchical structure and low-energy surface under severe conditions. The mechanical durability of the SSM-supported PSZB coating
Figure 2. Variations of WCAs and chloroform/water separation efficiencies (a) and chloroform fluxes and residual oil contents in water (b) with abrasion cycles for SSM-supported PSZB coatings. 8045
DOI: 10.1021/acs.iecr.9b00046 Ind. Eng. Chem. Res. 2019, 58, 8044−8049
Article
Industrial & Engineering Chemistry Research
compared with the pristine sample. With the increase of abrasion cycles, the surface of the PSZB coating became smoother, indicating that the rough hierarchical structure was gradually destroyed. Although mild destruction was observed on the regions positioned at the top of the PSZB coating after 80 abrasion cycles, the nanoscale structure at its low position was well retained (Figure 3f). Furthermore, the cross-sectional view of the SSM-supported PSZB coating after 80 abrasion cycles was given in Figure 3h. Compared with the assynthesized samples, the top layer after 80 abrasion cycles was smoother and exhibited a reduced thickness of ca. 9 μm. These observations were in accordance with the changes of WCAs and separation performances after abrasion treatments, further demonstrating the good mechanical durability of SSMsupported PSZB coatings. To further evaluate the robustness of fabricated SSMsupported PSZB coatings, corrosion treatment was performed by immersing them in corrosive media. The WCAs and chloroform/water separation efficiencies after being immersed in corrosive media are given in Figure 4a. The measured WCA on the PSZB surface remained above 150°, and the corresponding separation efficiency was kept above 99.5% after corrosion treatment. Furthermore, residual oil contents in water for samples after being immersed in corrosive media were lower than 0.645 mg g−1, and chloroform fluxes kept stable (Figure 4b). Obviously, the WCAs and chloroform/ water separation performances of the SSM-supported PSZB coatings after corrosion treatment were comparable to those of the untreated sample, demonstrating that the SSM-supported PSZB coatings maintained robust superhydrophobic characteristics under caustic conditions. The corresponding morphologies of SSM-supported PSZB coatings after corrosion treatment are displayed in Figure 5. Compared with the untreated sample (Figure 3b), the surface of PSZB coating had no significant variations after being treated with HCl and NaCl as shown in Figure 5a, b. Slight dissolution was observed on the PSZB surface after treatment with 0.1 M NaOH (Figure 5c); however, there was no decrease in separation performances at all (Figure 4), suggesting that the rough microstructure of the SSM-supported PSZB coating was not completely destroyed in this case. The temperature may change a lot in the actual application of oil/water separation, so it is essential to evaluate the thermal stability of SSM-supported PSZB coatings. In this experiment, the samples were heated to a set temperature and kept at the temperature for 1 h. As depicted in Figure 6, the hightemperature treatment below 250 °C had negligible influence on the surface wettability and chloroform/water separation performances of SSM-supported PSZB coatings during this scope. This excellent thermal stability could be attributed to the fact that the PSZB coating synthesized in a near-neutral medium containing fluoride had substantially fewer defect sites.16 However, after the heat treatment at 300 °C, the WCA decreased dramatically to 136.9°, and the corresponding separation efficiency dropped to 84.68%, while the residual oil content in water kept almost unchanged and the chloroform flux increased. The above results were further verified by SEM observations. As shown in Figure 7, compared with the pristine SSM-supported PSZB coating (Figure 3a), the PSZB coating maintained intact morphology after the treatment below 250 °C, while it shed off from the SSM surface after being heated at 300 °C (Figure 7e). This result could be interpreted by the difference of thermal expansion coefficients between the PSZB
was investigated via abrasion, which was carried out under a load weighing 25 g with sandpaper for multiple cycles. The variations of WCAs and chloroform/water separation efficiencies with abrasion cycles are displayed in Figure 2a. The untreated SSM-supported PSZB coating exhibited superhydrophobic characteristics with a WCA of 150.4° and a high separation efficiency of 99.6%. Compared with the pristine sample, it could be seen that WCAs had a slight fluctuation and were still greater than 150° even after 60 abrasion cycles. Once more than 80 abrasion cycles were carried out, the WCA decreased to approximately 148.9°, suggesting a reduction in the superhydrophobicity of the SSM-supported PSZB coating. Despite the decreased WCA, the chloroform/water separation efficiency remained above 99% over 80 abrasion cycles. In addition, the measured residual oil content in water and chloroform flux were almost unchanged (Figure 2b). These results demonstrated that the SSM-supported PSZB coating had a superior mechanical durability under the abrasion treatment up to 80 cycles, which could be ascribed to the dense crystalline backbone of zeolite beta crystals.23 SEM images were displayed to illustrate the change of surface morphology after abrasion test (Figure 3). Figure 3a, b, g
Figure 3. SEM images of SSM-supported PSZB coatings: (a, b) assynthesized samples and (c−f) the samples after being abrased for 20, 40, 60, and 80 cycles. Cross-sectional views of SSM-supported PSZB coatings: (g) as-synthesized samples and (h) the samples after being abrased for 80 cycles.
shows the morphology of untreated SSM-supported PSZB coatings. The intergrown PSZB crystal layer around 11 μm in thickness was fabricated on the SSM support to form a micro/ nanoscale hierarchical structure with low surface energy. Figure 3c−f shows the corresponding surface structure of the SSMsupported PSZB coating after abrasion treatment under a load weighing 25 g for 20, 40, 60, and 80 times. Severe destruction on the surface was not observed, and the intergrown truncated bipyramidal morphology remained over 60 abrasion cycles 8046
DOI: 10.1021/acs.iecr.9b00046 Ind. Eng. Chem. Res. 2019, 58, 8044−8049
Article
Industrial & Engineering Chemistry Research
Figure 4. WCAs and chloroform/water separation efficiencies (a) and chloroform fluxes and residual oil contents in water (b) of SSM-supported PSZB coatings before and after treatment with corrosive media for 24 h.
Figure 5. SEM images of SSM-supported PSZB coatings after immersion in (a) 0.1 M HCl, (b) 1 M NaCl, and (c) 0.1 M NaOH for 24 h. Scale bar: 10 μm.
coating and the SSM support.24 The destruction of low-energy surface from the PSZB coating and micro/nanoscale hierarchical structure on the SSM support resulted in the disappearance of superhydrophobicity, and the detachment of the PSZB coatings gave rise to the augmented pore size of the SSM, leading to an increase in the chloroform flux. This was consistent with the changes of both WCAs and chloroform/ water separation performances, which confirmed that the PSZB coating on the SSM support possessed excellent thermal stability. Furthermore, the PSZB coating could keep a close attachment on the SSM support even after high-temperature treatment below 250 °C. Furthermore, the ultrasonic treatment was employed to test the adhesive strength of the PSZB coating on the substrate. The samples were immersed into chloroform solvent, followed by ultrasonic treatment. Figure 8 shows the changes in WCAs and chloroform/water separation performances of the SSM-
Figure 7. SEM images of SSM-supported PSZB coatings after hightemperature treatment at (a) 100, (b) 150, (c) 200, (d) 250, and (e) 300 °C for 1 h. Scale bar: 50 μm.
supported PSZB coatings with treatment time. Although the WCA of the PSZB coating decreased slightly with treatment time, the value was still larger than 150°. Meanwhile, the separation efficiencies of the SSM-supported PSZB coatings remained above 99.3% with almost constant residual oil contents in water and chloroform fluxes, suggesting that the SSM-supported PSZB coating maintained its superhydrophobicity after ultrasonic treatment for 60 min. These results would be further confirmed by SEM observations as below. As shown in Figure 9, no detachment of the PSZB coating from the support was observed. The SSM-supported PSZB coating
Figure 6. Dependence of WCAs and chloroform/water separation efficiencies (a) and chloroform fluxes and residual oil contents in water (b) of SSM-supported PSZB coatings on high-temperature treatments. 8047
DOI: 10.1021/acs.iecr.9b00046 Ind. Eng. Chem. Res. 2019, 58, 8044−8049
Article
Industrial & Engineering Chemistry Research
Figure 8. WCAs and the chloroform/water separation efficiencies (a) and chloroform fluxes and residual oil contents in water (b) of SSMsupported PSZB coatings measured with respect to ultrasonic time in chloroform solvent.
■
ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.iecr.9b00046.
■
Figure 9. SEM images of SSM-supported PSZB coatings after sonication for (a) 20, (b) 40, and (c) 60 min. Scale bar: 50 μm.
Materials and chemicals (PDF)
AUTHOR INFORMATION
Corresponding Author
*Tel./Fax: +86 2285356517; E-mail: [email protected]. ORCID
showed the similar surface morphology to the pristine sample (Figure 3a) and maintained intact surface microstructure after ultrasonication, demonstrating robust adhesion of the PSZB coating on the substrate. It is noteworthy that SSM-supported PSZB coatings could be synthesized under microwave-assisted heating to substantially reduce the crystallization time.25 The template-free fabrication of zeolite beta layers could lower the feedstock cost remarkably.26−28 The adoption of these synthesis methods might achieve an energy- and cost-effective way for production of SSM-supported PSZB coatings and will be explored in the future.
Baoquan Zhang: 0000-0001-7571-8103 Notes
The authors declare no competing financial interest.
■
ACKNOWLEDGMENTS We are grateful for the financial support from the National Natural Science Foundation of China (Grant 21136008).
■
REFERENCES
(1) Xue, Z. X.; Cao, Y. Z.; Liu, N.; Feng, L.; Jiang, L. Special wettable materials for oil/water separation. J. Mater. Chem. A 2014, 2, 2445−2460. (2) Jiang, Z. R.; Ge, J.; Zhou, Y. X.; Wang, Z. Y. U.; Chen, D. X.; Yu, S. H.; Jiang, H. L. Coating sponge with a hydrophobic porous coordination polymer containing a low-energy CF3-decorated surface for continuous pumping recovery of an oil spill from water. NPG Asia Mater. 2016, 8, No. e253. (3) Hou, L. L.; Wang, N.; Wu, J.; Cui, Z. M.; Jiang, L.; Zhao, Y. Bioinspired superwettabilityelectrospun micro/nanofibers and their applications. Adv. Funct. Mater. 2018, 28, 1801114. (4) Yang, X.; Cheng, M. J.; Zhang, L. N.; Zhang, S.; Liu, X. L.; Shi, F. Electricity generation through light-responsive diving-surfacing locomotion of a functionally cooperating smart device. Adv. Mater. 2018, 30, 1803125. (5) Song, M. M.; Cheng, M. J.; Xiao, M.; Zhang, L. N.; Ju, G. N.; Shi, F. Biomimicking of a swim bladder and its application as a minigenerator. Adv. Mater. 2017, 29, 1603312. (6) Ma, Q. L.; Cheng, H. F.; Fane, A. G.; Wang, R.; Zhang, H. Recent development of advanced materials with special wettability for selective oil/water separation. Small 2016, 12, 2186−2202. (7) Feng, L.; Zhang, Z. Y.; Mai, Z. H.; Ma, Y. M.; Liu, B. Q.; Jiang, L.; Zhu, D. B. A super-hydrophobic and super-oleophilic coating mesh film for the separation of oil and water. Angew. Chem., Int. Ed. 2004, 43, 2012−2014.
4. CONCLUSIONS SSM-supported PSZB coatings with superhydrophobic characteristics were fabricated by using secondary growth method. The durability and stability of the SSM-supported PSZB coating have been investigated thoroughly under various treatment conditions. The SSM-supported PSZB coating possessed excellent mechanical durability, corrosion resistance, and thermal stability. It could maintain superhydrophobicity with WCAs of over 150° and exhibit high separation efficiencies of above 99% with trace amount of residual oil contents in water when exposed to abrasion, corrosive media, and high-temperature environments. Meanwhile, these treatments have negligible influence on chloroform fluxes of the SSM-supported PSZB coating. In addition, the PSZB coating has shown a strong attachment to the SSM surface and retained its superhydrophobicity even after exposure to 250 °C and ultrasonic environments for 1 h. It can be expected that the robust zeolite-coated SSMs with superior durability and stability would fulfill actual applications in oil/water separation. 8048
DOI: 10.1021/acs.iecr.9b00046 Ind. Eng. Chem. Res. 2019, 58, 8044−8049
Article
Industrial & Engineering Chemistry Research (8) Li, j; Yan, L.; Ouyang, Q. L.; Zha, F.; Jing, Z. J.; Li, X.; Lei, Z. Q. Facile fabrication of translucent superamphiphobic coating on paper to prevent liquid pollution. Chem. Eng. J. 2014, 246, 238−243. (9) Jiang, B.; Zhang, H. J.; Zhang, L. H.; Sun, Y. L.; Xu, L. D.; Sun, Z. N.; Gu, W. H.; Chen, Z. X.; Yang, H. W. Novel one-step, in situ thermal polymerization fabrication of robust superhydrophobic mesh for efficient oil/water separation. Ind. Eng. Chem. Res. 2017, 56, 11817−11826. (10) Li, J.; Kang, R. M.; Tang, X. H.; She, H. D.; Yang, Y. X.; Zha, F. Superhydrophobic meshes that can repel hot water and strong corrosive liquids used for efficient gravity-driven oil/water separation. Nanoscale 2016, 8, 7638−7645. (11) Long, Y. F.; Shen, Y. Q.; Tian, H. F.; Yang, Y. X.; Feng, H.; Li, J. Superwettablecoprinuscomatus coated membranes used toward the controllable separation of emulsified oil/water mixtures. J. Membr. Sci. 2018, 565, 85−94. (12) Li, J.; Xu, C. C.; Guo, C. Q.; Tian, H. F.; Zha, F.; Guo, L. Underoil superhydrophilic desert sand layer for efficient gravitydirected water-in-oil emulsions separation with high flux. J. Mater. Chem. A 2018, 6, 223−230. (13) Li, H.; Zheng, M. J.; Ma, L.; Zhu, C. Q.; Lu, S. Twodimensional ZnO nanoflakes coated mesh for the separation of water and oil. Mater. Res. Bull. 2013, 48, 25−29. (14) Jing, X. S.; Guo, Z. G. Biomimetic super durable and stable surfaces with superhydrophobicity. J. Mater. Chem. A 2018, 6, 16731− 16768. (15) Lew, C. M.; Cai, R.; Yan, Y. S. Zeolite thin films: from computer chips to space stations. Acc. Chem. Res. 2010, 43, 210−219. (16) Jon, H.; Lu, B. W.; Oumi, Y.; Itabashi, K.; Sano, T. Synthesis and thermal stability of beta zeolite using ammonium fluoride. Microporous Mesoporous Mater. 2006, 89, 88−95. (17) Mitra, A.; Wang, Z. B.; Cao, T. G.; Wang, H. T.; Huang, L. M.; Yan, Y. S. Synthesis and corrosion resistance of high-silica zeolite MTW, BEA, and MFI coatings on steel and aluminum. J. Electrochem. Soc. 2002, 149, B472−B478. (18) Wen, Q.; Di, J. C.; Jiang, L.; Yu, J. H.; Xu, R. R. Zeolite-coated mesh film for efficient oil−water separation. Chem. Sci. 2013, 4, 591− 595. (19) Liu, R. C.; Dangwal, S.; Shaik, I.; Aichele, C.; Kim, S. J. Hydrophilicity-controlled MFI-type zeolite-coated mesh for oil/water separation. Sep. Purif. Technol. 2018, 195, 163−169. (20) Zeng, J. W.; Guo, Z. G. Superhydrophilic and underwater superoleophobic MFI zeolite-coated film for oil/water separation. Colloids Surf., A 2014, 444, 283−288. (21) Li, Y.; Shang, X. Z.; Zhang, B. Q. One-step fabrication of the pure-silica zeolite beta coating on stainless steel mesh for efficient oil/ water separation. Ind. Eng. Chem. Res. 2018, 57, 17409−17416. (22) Guo, D. Y.; Hou, K.; Xu, S. P.; Lin, Y. G.; Li, L.; Wen, X. F.; Pi, P. H. Superhydrophobic-superoleophilic stainless steel meshes by spray-coating of a POSS hybrid acrylic polymer for oil−water separation. J. Mater. Sci. 2018, 53, 6403−6413. (23) Mitra, A.; Cao, T. G.; Wang, H. T.; Wang, Z. B.; Huang, L. M.; Li, S.; Li, Z. J.; Yan, Y. S. Synthesis and evaluation of pure-silicazeolite BEA as low dielectric constant material for microprocessors. Ind. Eng. Chem. Res. 2004, 43, 2946−2949. (24) Dong, J. H.; Lin, Y. S.; Hu, M. Z. C.; Peascoe, R. A.; Payzant, E. A. Template-removal-associated microstructural development of porous-ceramic-supported MFI zeolite membranes. Microporous Mesoporous Mater. 2000, 34, 241−253. (25) Muraza, O.; Rebrov, E. V.; Chen, J. Y.; Putkonen, M.; Niinistö, L.; de Croon, M. H. J. M.; Schouten, J. C. Microwave-assisted hydrothermal synthesis of zeolite Beta coatings on ALD-modified borosilicate glass for application inmicrostructured reactors. Chem. Eng. J. 2008, 135, S117−S120. (26) Reuss, S.; Sanwald, D.; Schülein, M.; Schwieger, W.; AlThabaiti, S. A.; Mokhtar, M.; Basahel, S. N. Supported zeolite beta layers via an organic template-free preparation route. Molecules 2018, 23, 220−231.
(27) Tang, Y. T.; Liu, X. F.; Nai, S. F.; Zhang, B. Q. Template-free synthesis of beta zeolite membranes on porous h-Al2O3 supports. Chem. Commun. 2014, 50, 8834−8837. (28) Xie, B.; Song, J. W.; Ren, L. M.; Ji, Y. Y.; Li, J. X.; Xiao, F. S. Organotemplate-free and fast route for synthesizing beta zeolite. Chem. Mater. 2008, 20, 4533−4535.
8049
DOI: 10.1021/acs.iecr.9b00046 Ind. Eng. Chem. Res. 2019, 58, 8044−8049
pubs.acs.org/IECR
Durability and Stability of Superhydrophobic Stainless Steel Mesh Supported Pure-Silica Zeolite Beta Coatings Yun Li, Xiufeng Liu, and Baoquan Zhang* State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China
Downloaded via UNIV OF GOTHENBURG on October 22, 2019 at 14:32:19 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.
S Supporting Information *
ABSTRACT: The poor durability and stability of superhydrophobic materials under various working conditions limit their widespread applications. Zeolite films have attracted considerable attention owing to their good mechanical, thermal, and chemical stabilities. Stainless steel mesh (SSM) supported pure-silica zeolite beta (PSZB) coatings with superhydrophobicity were fabricated using secondary growth method. The durability and stability of SSM-supported PSZB coatings were investigated thoroughly after undergoing various treatments, including abrasion, corrosion, high temperature, and ultrasonication. The SSM-supported PSZB coatings could maintain their superhydrophobicity and high separation efficiencies above 99% with trace amount of oil contents in water as well as stable chloroform fluxes after abrasion for 80 cycles or exposure to corrosive media. The PSZB coating could keep a close attachment on the SSM support in hightemperature and ultrasonication environments. This work demonstrated the satisfactory durability and stability of SSMsupported PSZB coatings and gives promise for zeolite-coated SSMs in actual oil/water separation. wettability.19 Guo et al. fabricated the silicalite-1 film on SSM with both superamphiphilicity in air and superoleophobicity underwater.20 In our previous work, the SSM-supported puresilica zeolite beta (PSZB) coating was prepared by using the seeded-growth method.21 The rough hierarchical structure on the outer surface of synthesized SSM-supported PSZB coatings together with intrinsic hydrophobicity of PSZB give both superhydrophobicity and superoleophilicity. It was demonstrated that the SSM-supported PSZB coating exhibited high separation efficiencies for oil/water mixtures.21 However, the durability and stability of these materials have not been checked systematically when exposed to rigorous operation conditions, including high temperature, strong corrosive media, and mechanical damages. With respect to superhydrophobic SSM-supported PSZB coatings, the changes in both surface morphology and separation performances were evaluated by way of abrasion, corrosion, heating, and sonication in this contribution. It is demonstrated that the SSM-supported PSZB coatings possess satisfactory mechanical durability, corrosion resistance, and thermal stability. They could retain superhydrophobic characteristics and high separation performances after various treatments.
1. INTRODUCTION Superwettable materials have been widely used in the field of oil/water separation,1,2 unidirectional liquid penetration,3 and other smart applications.4,5 Of reported superwettable materials, stainless steel mesh (SSM)-based materials with superhydrophobicity have drawn much attention to oil/water separation owing to their satisfactory performances and ease of operation.6 Polymers and inorganic substances have been employed to modify SSMs by spraying,7,8 thermal polymerization,9 combustion,10 vacuum suction,11 stacking,12 and hydrothermal crystallization.13 Although these materials exhibit high separation performances for a variety of oil/water mixtures, most of them would lose their superhydrophobicity when immersed in corrosive media or exposed to hightemperature environments or suffer mechanical damages as a result of the destruction of micro/nanoscale hierarchical structures and/or low-energy surface, eventually hindering development of their actual applications.14 Zeolites show excellent mechanical, thermal, and chemical stabilities due to their dense crystalline backbone.15−17 Thus, it is desirable to fabricate robust zeolite films with special wetting ability for actual oil/water separation. Currently, there are only a few reports about SSM supported zeolite coatings with superwettability. Yu et al. designed the silicalite-1 coated SSM with superhydrophilicity and underwater superoleophobicity to separate water from oil.18 Kim et al. prepared the MFI-type zeolite-coated SSM using in situ crystallization method and studied the effect of Al/Si ratio on the membrane surface © 2019 American Chemical Society
Received: Revised: Accepted: Published: 8044
January 3, 2019 April 5, 2019 April 24, 2019 April 24, 2019 DOI: 10.1021/acs.iecr.9b00046 Ind. Eng. Chem. Res. 2019, 58, 8044−8049
Article
Industrial & Engineering Chemistry Research
flushed with N2. The high-temperature treatment was carried out to demonstrate the thermal stability of SSM-supported PSZB coatings. The sample was heated to a set temperature and kept there for 1 h, and the sample cooled at last. The ultrasonication treatment was employed to check the adhesive strength of the superhydrophobic coating on the support. Samples were subjected to sonication with 200 W in chloroform solvent for a specific time period. The samples after ultrasonication treatment were washed by ethanol and flushed with N2. The surface wettability of all treated samples was estimated according to the static water contact angle (WCA) measurement. The oil/water separation of treated SSM-supported PSZB coatings was also carried out to illustrate the effect of various treatments on separation performances. 2.3. Characterization. The morphologies of SSMsupported PSZB coatings were obtained via scanning electron microscopy (SEM, Hitachi S-4800). The surface wettability of SSM-supported PSZB coatings was measured by static WCAs (Dataphysics OCAH 200) with the drop size of ∼3 μL. The final value was reported as the mean of three experiments. 2.4. Oil/Water Separation. The oil/water separation was conducted as reported previously.21 Chloroform permeated through the SSM-supported PSZB coating, while water was intercepted. The separation efficiency was defined according to η% = (m1/m0) × 100, for which m0 is the mass of water before the separation process and m1 the mass of water intercepted in the upper tube.10 The residual oil content in water was measured by using a Ke-Chuang 9800 gas chromatograph equipped with a thermal conductivity detector. In addition, the chloroform flux was measured to describe the separation performance of the SSM-supported PSZB coatings.21 The setup was the same as the above separation system. Chloroform was poured, and the liquid level was maintained at the height of 10 cm. The volume (V) of permeated chloroform was recorded. The flux (F) was calculated according to F = V/(S × t), where S is the film area and t the permeation time.21 The final result was taken from three repeated experiments.
2. EXPERIMENTAL SECTION 2.1. Synthesis of SSM-Supported PSZB Coatings. The detailed descriptions about materials and chemical reagents used in this experiment are available in the Supporting Information. The SSM-supported PSZB coating was prepared by secondary growth method as reported previously.21 First, the polydopamine modified method was employed to prepare seed layers on the surface of SSMs with high coverage degree. The dealuminated zeolite beta seeds were redispersed into freshly prepared Tris(hydroxy-methyl) aminomethane (Tris) buffer solution to form a 0.5 wt % suspension. The preprepared SSM (350 mesh, 3 × 3 cm) was immersed into the seed suspension with dopamine (DA) for 20 h and dried at 60 °C. Then, the seeded SSM was treated in a synthesis gel with a molar composition of tetraethylammonium hydroxide (TEAOH):SiO2:hydrofluoric acid (HF):H2O:n-propanol = 0.6:1.0:0.6:7:2.4. The fumed silica was dissolved in TEAOH solution at 80 °C under vigorous stirring. HF was added to the obtained synthesis gel, resulting in the formation of light yellow solid. Then, to the above solid, n-propanol was added with stirring, forming a homogeneous gel. After being aged for 24 h, the resultant gel was transferred to a Teflon-lined autoclave, where the seeded substrate was placed vertically. The hydrothermal treatment was carried out at 140 °C for 7 d. The as-synthesized samples were cleaned by deionized water (DI H2O) and dried with nitrogen (N2) purging. 2.2. Postsynthetic Treatments. The abrasion on the SSM-supported PSZB coating was performed to investigate its mechanical durability. As shown in Figure 1, a sample was
Figure 1. Abrasion treatment of the SSM-supported PSZB coating on sandpaper.
moved 10 cm on a piece of sandpaper (2000 mesh) at a speed of 5 cm s−1 under a load weighing of 25 g for a number of repeated cycles.22 To investigate the chemical stability of the PSZB coating, samples were subjected to corrosion in 0.1 M HCl, 0.1 M NaOH, and 1 M NaCl for 24 h. After immersion, the samples were washed with DI H2O and ethanol and then
3. RESULTS AND DISCUSSION For actual applications, it is vital that superhydrophobic materials maintain their micro/nanoscale hierarchical structure and low-energy surface under severe conditions. The mechanical durability of the SSM-supported PSZB coating
Figure 2. Variations of WCAs and chloroform/water separation efficiencies (a) and chloroform fluxes and residual oil contents in water (b) with abrasion cycles for SSM-supported PSZB coatings. 8045
DOI: 10.1021/acs.iecr.9b00046 Ind. Eng. Chem. Res. 2019, 58, 8044−8049
Article
Industrial & Engineering Chemistry Research
compared with the pristine sample. With the increase of abrasion cycles, the surface of the PSZB coating became smoother, indicating that the rough hierarchical structure was gradually destroyed. Although mild destruction was observed on the regions positioned at the top of the PSZB coating after 80 abrasion cycles, the nanoscale structure at its low position was well retained (Figure 3f). Furthermore, the cross-sectional view of the SSM-supported PSZB coating after 80 abrasion cycles was given in Figure 3h. Compared with the assynthesized samples, the top layer after 80 abrasion cycles was smoother and exhibited a reduced thickness of ca. 9 μm. These observations were in accordance with the changes of WCAs and separation performances after abrasion treatments, further demonstrating the good mechanical durability of SSMsupported PSZB coatings. To further evaluate the robustness of fabricated SSMsupported PSZB coatings, corrosion treatment was performed by immersing them in corrosive media. The WCAs and chloroform/water separation efficiencies after being immersed in corrosive media are given in Figure 4a. The measured WCA on the PSZB surface remained above 150°, and the corresponding separation efficiency was kept above 99.5% after corrosion treatment. Furthermore, residual oil contents in water for samples after being immersed in corrosive media were lower than 0.645 mg g−1, and chloroform fluxes kept stable (Figure 4b). Obviously, the WCAs and chloroform/ water separation performances of the SSM-supported PSZB coatings after corrosion treatment were comparable to those of the untreated sample, demonstrating that the SSM-supported PSZB coatings maintained robust superhydrophobic characteristics under caustic conditions. The corresponding morphologies of SSM-supported PSZB coatings after corrosion treatment are displayed in Figure 5. Compared with the untreated sample (Figure 3b), the surface of PSZB coating had no significant variations after being treated with HCl and NaCl as shown in Figure 5a, b. Slight dissolution was observed on the PSZB surface after treatment with 0.1 M NaOH (Figure 5c); however, there was no decrease in separation performances at all (Figure 4), suggesting that the rough microstructure of the SSM-supported PSZB coating was not completely destroyed in this case. The temperature may change a lot in the actual application of oil/water separation, so it is essential to evaluate the thermal stability of SSM-supported PSZB coatings. In this experiment, the samples were heated to a set temperature and kept at the temperature for 1 h. As depicted in Figure 6, the hightemperature treatment below 250 °C had negligible influence on the surface wettability and chloroform/water separation performances of SSM-supported PSZB coatings during this scope. This excellent thermal stability could be attributed to the fact that the PSZB coating synthesized in a near-neutral medium containing fluoride had substantially fewer defect sites.16 However, after the heat treatment at 300 °C, the WCA decreased dramatically to 136.9°, and the corresponding separation efficiency dropped to 84.68%, while the residual oil content in water kept almost unchanged and the chloroform flux increased. The above results were further verified by SEM observations. As shown in Figure 7, compared with the pristine SSM-supported PSZB coating (Figure 3a), the PSZB coating maintained intact morphology after the treatment below 250 °C, while it shed off from the SSM surface after being heated at 300 °C (Figure 7e). This result could be interpreted by the difference of thermal expansion coefficients between the PSZB
was investigated via abrasion, which was carried out under a load weighing 25 g with sandpaper for multiple cycles. The variations of WCAs and chloroform/water separation efficiencies with abrasion cycles are displayed in Figure 2a. The untreated SSM-supported PSZB coating exhibited superhydrophobic characteristics with a WCA of 150.4° and a high separation efficiency of 99.6%. Compared with the pristine sample, it could be seen that WCAs had a slight fluctuation and were still greater than 150° even after 60 abrasion cycles. Once more than 80 abrasion cycles were carried out, the WCA decreased to approximately 148.9°, suggesting a reduction in the superhydrophobicity of the SSM-supported PSZB coating. Despite the decreased WCA, the chloroform/water separation efficiency remained above 99% over 80 abrasion cycles. In addition, the measured residual oil content in water and chloroform flux were almost unchanged (Figure 2b). These results demonstrated that the SSM-supported PSZB coating had a superior mechanical durability under the abrasion treatment up to 80 cycles, which could be ascribed to the dense crystalline backbone of zeolite beta crystals.23 SEM images were displayed to illustrate the change of surface morphology after abrasion test (Figure 3). Figure 3a, b, g
Figure 3. SEM images of SSM-supported PSZB coatings: (a, b) assynthesized samples and (c−f) the samples after being abrased for 20, 40, 60, and 80 cycles. Cross-sectional views of SSM-supported PSZB coatings: (g) as-synthesized samples and (h) the samples after being abrased for 80 cycles.
shows the morphology of untreated SSM-supported PSZB coatings. The intergrown PSZB crystal layer around 11 μm in thickness was fabricated on the SSM support to form a micro/ nanoscale hierarchical structure with low surface energy. Figure 3c−f shows the corresponding surface structure of the SSMsupported PSZB coating after abrasion treatment under a load weighing 25 g for 20, 40, 60, and 80 times. Severe destruction on the surface was not observed, and the intergrown truncated bipyramidal morphology remained over 60 abrasion cycles 8046
DOI: 10.1021/acs.iecr.9b00046 Ind. Eng. Chem. Res. 2019, 58, 8044−8049
Article
Industrial & Engineering Chemistry Research
Figure 4. WCAs and chloroform/water separation efficiencies (a) and chloroform fluxes and residual oil contents in water (b) of SSM-supported PSZB coatings before and after treatment with corrosive media for 24 h.
Figure 5. SEM images of SSM-supported PSZB coatings after immersion in (a) 0.1 M HCl, (b) 1 M NaCl, and (c) 0.1 M NaOH for 24 h. Scale bar: 10 μm.
coating and the SSM support.24 The destruction of low-energy surface from the PSZB coating and micro/nanoscale hierarchical structure on the SSM support resulted in the disappearance of superhydrophobicity, and the detachment of the PSZB coatings gave rise to the augmented pore size of the SSM, leading to an increase in the chloroform flux. This was consistent with the changes of both WCAs and chloroform/ water separation performances, which confirmed that the PSZB coating on the SSM support possessed excellent thermal stability. Furthermore, the PSZB coating could keep a close attachment on the SSM support even after high-temperature treatment below 250 °C. Furthermore, the ultrasonic treatment was employed to test the adhesive strength of the PSZB coating on the substrate. The samples were immersed into chloroform solvent, followed by ultrasonic treatment. Figure 8 shows the changes in WCAs and chloroform/water separation performances of the SSM-
Figure 7. SEM images of SSM-supported PSZB coatings after hightemperature treatment at (a) 100, (b) 150, (c) 200, (d) 250, and (e) 300 °C for 1 h. Scale bar: 50 μm.
supported PSZB coatings with treatment time. Although the WCA of the PSZB coating decreased slightly with treatment time, the value was still larger than 150°. Meanwhile, the separation efficiencies of the SSM-supported PSZB coatings remained above 99.3% with almost constant residual oil contents in water and chloroform fluxes, suggesting that the SSM-supported PSZB coating maintained its superhydrophobicity after ultrasonic treatment for 60 min. These results would be further confirmed by SEM observations as below. As shown in Figure 9, no detachment of the PSZB coating from the support was observed. The SSM-supported PSZB coating
Figure 6. Dependence of WCAs and chloroform/water separation efficiencies (a) and chloroform fluxes and residual oil contents in water (b) of SSM-supported PSZB coatings on high-temperature treatments. 8047
DOI: 10.1021/acs.iecr.9b00046 Ind. Eng. Chem. Res. 2019, 58, 8044−8049
Article
Industrial & Engineering Chemistry Research
Figure 8. WCAs and the chloroform/water separation efficiencies (a) and chloroform fluxes and residual oil contents in water (b) of SSMsupported PSZB coatings measured with respect to ultrasonic time in chloroform solvent.
■
ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.iecr.9b00046.
■
Figure 9. SEM images of SSM-supported PSZB coatings after sonication for (a) 20, (b) 40, and (c) 60 min. Scale bar: 50 μm.
Materials and chemicals (PDF)
AUTHOR INFORMATION
Corresponding Author
*Tel./Fax: +86 2285356517; E-mail: [email protected]. ORCID
showed the similar surface morphology to the pristine sample (Figure 3a) and maintained intact surface microstructure after ultrasonication, demonstrating robust adhesion of the PSZB coating on the substrate. It is noteworthy that SSM-supported PSZB coatings could be synthesized under microwave-assisted heating to substantially reduce the crystallization time.25 The template-free fabrication of zeolite beta layers could lower the feedstock cost remarkably.26−28 The adoption of these synthesis methods might achieve an energy- and cost-effective way for production of SSM-supported PSZB coatings and will be explored in the future.
Baoquan Zhang: 0000-0001-7571-8103 Notes
The authors declare no competing financial interest.
■
ACKNOWLEDGMENTS We are grateful for the financial support from the National Natural Science Foundation of China (Grant 21136008).
■
REFERENCES
(1) Xue, Z. X.; Cao, Y. Z.; Liu, N.; Feng, L.; Jiang, L. Special wettable materials for oil/water separation. J. Mater. Chem. A 2014, 2, 2445−2460. (2) Jiang, Z. R.; Ge, J.; Zhou, Y. X.; Wang, Z. Y. U.; Chen, D. X.; Yu, S. H.; Jiang, H. L. Coating sponge with a hydrophobic porous coordination polymer containing a low-energy CF3-decorated surface for continuous pumping recovery of an oil spill from water. NPG Asia Mater. 2016, 8, No. e253. (3) Hou, L. L.; Wang, N.; Wu, J.; Cui, Z. M.; Jiang, L.; Zhao, Y. Bioinspired superwettabilityelectrospun micro/nanofibers and their applications. Adv. Funct. Mater. 2018, 28, 1801114. (4) Yang, X.; Cheng, M. J.; Zhang, L. N.; Zhang, S.; Liu, X. L.; Shi, F. Electricity generation through light-responsive diving-surfacing locomotion of a functionally cooperating smart device. Adv. Mater. 2018, 30, 1803125. (5) Song, M. M.; Cheng, M. J.; Xiao, M.; Zhang, L. N.; Ju, G. N.; Shi, F. Biomimicking of a swim bladder and its application as a minigenerator. Adv. Mater. 2017, 29, 1603312. (6) Ma, Q. L.; Cheng, H. F.; Fane, A. G.; Wang, R.; Zhang, H. Recent development of advanced materials with special wettability for selective oil/water separation. Small 2016, 12, 2186−2202. (7) Feng, L.; Zhang, Z. Y.; Mai, Z. H.; Ma, Y. M.; Liu, B. Q.; Jiang, L.; Zhu, D. B. A super-hydrophobic and super-oleophilic coating mesh film for the separation of oil and water. Angew. Chem., Int. Ed. 2004, 43, 2012−2014.
4. CONCLUSIONS SSM-supported PSZB coatings with superhydrophobic characteristics were fabricated by using secondary growth method. The durability and stability of the SSM-supported PSZB coating have been investigated thoroughly under various treatment conditions. The SSM-supported PSZB coating possessed excellent mechanical durability, corrosion resistance, and thermal stability. It could maintain superhydrophobicity with WCAs of over 150° and exhibit high separation efficiencies of above 99% with trace amount of residual oil contents in water when exposed to abrasion, corrosive media, and high-temperature environments. Meanwhile, these treatments have negligible influence on chloroform fluxes of the SSM-supported PSZB coating. In addition, the PSZB coating has shown a strong attachment to the SSM surface and retained its superhydrophobicity even after exposure to 250 °C and ultrasonic environments for 1 h. It can be expected that the robust zeolite-coated SSMs with superior durability and stability would fulfill actual applications in oil/water separation. 8048
DOI: 10.1021/acs.iecr.9b00046 Ind. Eng. Chem. Res. 2019, 58, 8044−8049
Article
Industrial & Engineering Chemistry Research (8) Li, j; Yan, L.; Ouyang, Q. L.; Zha, F.; Jing, Z. J.; Li, X.; Lei, Z. Q. Facile fabrication of translucent superamphiphobic coating on paper to prevent liquid pollution. Chem. Eng. J. 2014, 246, 238−243. (9) Jiang, B.; Zhang, H. J.; Zhang, L. H.; Sun, Y. L.; Xu, L. D.; Sun, Z. N.; Gu, W. H.; Chen, Z. X.; Yang, H. W. Novel one-step, in situ thermal polymerization fabrication of robust superhydrophobic mesh for efficient oil/water separation. Ind. Eng. Chem. Res. 2017, 56, 11817−11826. (10) Li, J.; Kang, R. M.; Tang, X. H.; She, H. D.; Yang, Y. X.; Zha, F. Superhydrophobic meshes that can repel hot water and strong corrosive liquids used for efficient gravity-driven oil/water separation. Nanoscale 2016, 8, 7638−7645. (11) Long, Y. F.; Shen, Y. Q.; Tian, H. F.; Yang, Y. X.; Feng, H.; Li, J. Superwettablecoprinuscomatus coated membranes used toward the controllable separation of emulsified oil/water mixtures. J. Membr. Sci. 2018, 565, 85−94. (12) Li, J.; Xu, C. C.; Guo, C. Q.; Tian, H. F.; Zha, F.; Guo, L. Underoil superhydrophilic desert sand layer for efficient gravitydirected water-in-oil emulsions separation with high flux. J. Mater. Chem. A 2018, 6, 223−230. (13) Li, H.; Zheng, M. J.; Ma, L.; Zhu, C. Q.; Lu, S. Twodimensional ZnO nanoflakes coated mesh for the separation of water and oil. Mater. Res. Bull. 2013, 48, 25−29. (14) Jing, X. S.; Guo, Z. G. Biomimetic super durable and stable surfaces with superhydrophobicity. J. Mater. Chem. A 2018, 6, 16731− 16768. (15) Lew, C. M.; Cai, R.; Yan, Y. S. Zeolite thin films: from computer chips to space stations. Acc. Chem. Res. 2010, 43, 210−219. (16) Jon, H.; Lu, B. W.; Oumi, Y.; Itabashi, K.; Sano, T. Synthesis and thermal stability of beta zeolite using ammonium fluoride. Microporous Mesoporous Mater. 2006, 89, 88−95. (17) Mitra, A.; Wang, Z. B.; Cao, T. G.; Wang, H. T.; Huang, L. M.; Yan, Y. S. Synthesis and corrosion resistance of high-silica zeolite MTW, BEA, and MFI coatings on steel and aluminum. J. Electrochem. Soc. 2002, 149, B472−B478. (18) Wen, Q.; Di, J. C.; Jiang, L.; Yu, J. H.; Xu, R. R. Zeolite-coated mesh film for efficient oil−water separation. Chem. Sci. 2013, 4, 591− 595. (19) Liu, R. C.; Dangwal, S.; Shaik, I.; Aichele, C.; Kim, S. J. Hydrophilicity-controlled MFI-type zeolite-coated mesh for oil/water separation. Sep. Purif. Technol. 2018, 195, 163−169. (20) Zeng, J. W.; Guo, Z. G. Superhydrophilic and underwater superoleophobic MFI zeolite-coated film for oil/water separation. Colloids Surf., A 2014, 444, 283−288. (21) Li, Y.; Shang, X. Z.; Zhang, B. Q. One-step fabrication of the pure-silica zeolite beta coating on stainless steel mesh for efficient oil/ water separation. Ind. Eng. Chem. Res. 2018, 57, 17409−17416. (22) Guo, D. Y.; Hou, K.; Xu, S. P.; Lin, Y. G.; Li, L.; Wen, X. F.; Pi, P. H. Superhydrophobic-superoleophilic stainless steel meshes by spray-coating of a POSS hybrid acrylic polymer for oil−water separation. J. Mater. Sci. 2018, 53, 6403−6413. (23) Mitra, A.; Cao, T. G.; Wang, H. T.; Wang, Z. B.; Huang, L. M.; Li, S.; Li, Z. J.; Yan, Y. S. Synthesis and evaluation of pure-silicazeolite BEA as low dielectric constant material for microprocessors. Ind. Eng. Chem. Res. 2004, 43, 2946−2949. (24) Dong, J. H.; Lin, Y. S.; Hu, M. Z. C.; Peascoe, R. A.; Payzant, E. A. Template-removal-associated microstructural development of porous-ceramic-supported MFI zeolite membranes. Microporous Mesoporous Mater. 2000, 34, 241−253. (25) Muraza, O.; Rebrov, E. V.; Chen, J. Y.; Putkonen, M.; Niinistö, L.; de Croon, M. H. J. M.; Schouten, J. C. Microwave-assisted hydrothermal synthesis of zeolite Beta coatings on ALD-modified borosilicate glass for application inmicrostructured reactors. Chem. Eng. J. 2008, 135, S117−S120. (26) Reuss, S.; Sanwald, D.; Schülein, M.; Schwieger, W.; AlThabaiti, S. A.; Mokhtar, M.; Basahel, S. N. Supported zeolite beta layers via an organic template-free preparation route. Molecules 2018, 23, 220−231.
(27) Tang, Y. T.; Liu, X. F.; Nai, S. F.; Zhang, B. Q. Template-free synthesis of beta zeolite membranes on porous h-Al2O3 supports. Chem. Commun. 2014, 50, 8834−8837. (28) Xie, B.; Song, J. W.; Ren, L. M.; Ji, Y. Y.; Li, J. X.; Xiao, F. S. Organotemplate-free and fast route for synthesizing beta zeolite. Chem. Mater. 2008, 20, 4533−4535.
8049
DOI: 10.1021/acs.iecr.9b00046 Ind. Eng. Chem. Res. 2019, 58, 8044−8049