scholarly journals Nanoporous zirconia microspheres prepared by salt-assisted spray drying

2020 ◽  
Vol 2 (5) ◽  
Author(s):  
M. Skovgaard ◽  
M. Gudik-Sørensen ◽  
K. Almdal ◽  
A. Ahniyaz

Abstract Nanoporous zirconia with high surface area and crystallinity has a wide range of industrial applications, such as in inorganic exchangers for ion exchange columns, catalyst substrates, and packing material for HPLC. Spherical particles of crystalline nanoporous zirconia are highly desired in various industries due to easy handling of the materials in a fluidized bed. Here, spray drying was adopted to produce spherical nanoporous zirconia powders in both laboratory scale and pilot plant scale. Effect of salts on spray-dried ZrO2 powders and their crystallization behavior was studied. It was found that addition of salts to the zirconia precursors has a huge effect on the crystallization of nanoporous zirconia powders. These results have a great impact on the development of microspheres of nanocrystalline ZrO2 and potentially open up a new opportunity to the low-cost production of porous ceramic microspheres with the salt templating method, in general.

2016 ◽  
Vol 852 ◽  
pp. 1455-1462
Author(s):  
Jie Zhang ◽  
Yong Heng Zhu ◽  
Shi Zao Kang ◽  
Xiang Qing Li ◽  
Jia Qiang Xu

In this paper, different SBA-15 molecular sieves were prepared in a facile sol-gel method by using a low-cost sodium silicate as silicon source at different ripening temperature. The materials were characterized by small-angle XRD, TEM, nitrogen adsorption–desorption test. The results showed that ripening temperature can affect the pore size and mesostructure of SBA-15. High surface area SBA-15 can be obtained at low ripening temperature, and plugged mesostructure can be prepared at high temperature. The gravimetric humidity sensing property of the materials were tested based on a transducer of quartz crystal microbalance. The test results revealed that all the samples showed high response in the wide range of relative humidity. The sensors based on that prepared at 35°C show a good stability and linearity in the range of 11.3%RH to 98%RRH along with fast response (12s) and recovery time (8s), ultrahigh sensitivity and low hysteresis, implying that has a great potential for humidity detection.


1993 ◽  
Vol 330 ◽  
Author(s):  
Peter D. Unger ◽  
Ronald P. Rohrbach

ABSTRACTThe technology to manufacture rigid, highly porous materials of very low density that are suitable for use in a wide range of industrial applications has recently been developed in this laboratory. These materials, derived from naturally occurring polymers, have many useful physical characteristics including very large pore volume, pore size distribution in a useful range, and high surface area. These characteristicsw, hen combinedw ith their robust mechanicals trength, make them potentially useful as support matrices for various complexing agents. One demonstrated application of this material is as a polymeric carrierfo r selective liquid metal extractants in hydrometallurgicalp rocesses. We have successfully impregnated our porous matrix with several selective metal extractants, and demonstrated retention of the basic metal binding properties of the immobilized agent. Results of bench scale pilot studies using a copper selective impregnated resin indicate excellent capacity, and good selectivity and extraction/elution kinetics.


2021 ◽  
Author(s):  
José Arnaldo Santana Costa ◽  
Vinicius Câmara Costa ◽  
Matheus Lima de Mello ◽  
Caio Marcio Paranhos

Abstract This study describes the sustainable and eco-friendly synthesis of the silica-based mesoporous structure from the use of alternative amorphous silica extracted from rice husk ash (RHA). The mesoporous material was called MCM-48 (RHA) and its application as adsorbent to the antimony (Sb) remediation in wastewater was tested. The adsorbent was prepared by an efficient and sustainable hydrothermal method, which exhibited an amorphous framework with type IV isotherms and type H1 hysteresis, high surface area (820.94 m2 g−1) and total pore volume (0.55 cm3 g−1) with a narrow mesopores distribution, uniform spherical particles, and well-defined architecture. Multivariate optimization using a factorial design (24) was employed in the adsorption tests of Sb. The variables evaluated and the conditions selected were: adsorbent mass (45 mg); adsorption time (60 min); pH (ranged from 2 to 10); and concentration of the Sb standard (8 mol L−1). The adsorbent material proposed in this study proved to be efficient for Sb remediation in aqueous media, mainly because it is a material with easy access, low-cost, and eco-friendly.


2008 ◽  
Vol 368-372 ◽  
pp. 1706-1708
Author(s):  
Ruo Bing Han ◽  
Chun Lei Wan ◽  
Hui Wu ◽  
Wei Pan

A novel templating method for preparing nanoporous materials has been developed. Spherical nickel phosphate particles synthesized through a homogeneous precipitation method were used as templates after annealing to fabricate porous metals. Effort of annealing temperature on the morphology of the spherical particles and the structure of outcome materials were studied. Hierarchical nanoporous metal with a high surface area was obtained using a template annealed at 200 oC.


Química Nova ◽  
2021 ◽  
Author(s):  
Luiza Mercante ◽  
Rafaela Andre ◽  
Juliana Macedo ◽  
Adriana Pavinatto ◽  
Daniel Correa

ELECTROSPUN NANOFIBERS AND THEIR APPLICATIONS: ADVANCES IN THE LAST DECADE. In recent years there has been an increasing interest in the development of nanomaterials with improved properties compared to their counterparts at the micro- and macroscopic scale. In this context, nanofibers obtained by electrospinning technique are highly attractive due to the unique combination of high surface area/volume ratio, porosity, flexibility, mechanical performance, simple processing and relatively low cost. In addition, the possibility to buildup nanofibers with different compositions, structures and properties allows the design of nanostructures for a wide range of applications. In this review, we will discuss the advances of the last decade in the use of the electrospinning to obtain nanofibers with different compositions and morphologies for varied applications. Specifically, we are interested in providing an overview of the state of the art in relation to the application of nanofibers in different areas, including healthcare, environment, sensing and energy. Finally, we will discuss the real perspective in terms of industrial application and future trends that have been pursued to improve the performance of electrospun nanofibers. This review will help researchers to understand the evolution and challenges of the area and will also stimulate even more interest in the development of new devices based on electrospun nanofibers


RSC Advances ◽  
2021 ◽  
Vol 11 (33) ◽  
pp. 20601-20611
Author(s):  
Md. Mijanur Rahman ◽  
Kenta Inaba ◽  
Garavdorj Batnyagt ◽  
Masato Saikawa ◽  
Yoshiki Kato ◽  
...  

Herein, we demonstrated that carbon-supported platinum (Pt/C) is a low-cost and high-performance electrocatalyst for polymer electrolyte fuel cells (PEFCs).


Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 657
Author(s):  
Geul Han Kim ◽  
Yoo Sei Park ◽  
Juchan Yang ◽  
Myeong Je Jang ◽  
Jaehoon Jeong ◽  
...  

Developing high performance, highly stable, and low-cost electrodes for the oxygen evolution reaction (OER) is challenging in water electrolysis technology. However, Ir- and Ru-based OER catalysts with high OER efficiency are difficult to commercialize as precious metal-based catalysts. Therefore, the study of OER catalysts, which are replaced by non-precious metals and have high activity and stability, are necessary. In this study, a copper–cobalt oxide nanosheet (CCO) electrode was synthesized by the electrodeposition of copper–cobalt hydroxide (CCOH) on Ni foam followed by annealing. The CCOH was annealed at various temperatures, and the structure changed to that of CCO at temperatures above 250 °C. In addition, it was observed that the nanosheets agglomerated when annealed at 300 °C. The CCO electrode annealed at 250 °C had a high surface area and efficient electron conduction pathways as a result of the direct growth on the Ni foam. Thus, the prepared CCO electrode exhibited enhanced OER activity (1.6 V at 261 mA/cm2) compared to those of CCOH (1.6 V at 144 mA/cm2), Co3O4 (1.6 V at 39 mA/cm2), and commercial IrO2 (1.6 V at 14 mA/cm2) electrodes. The optimized catalyst also showed high activity and stability under high pH conditions, demonstrating its potential as a low cost, highly efficient OER electrode material.


Author(s):  
Guru Venkatesan ◽  
Andy Sarles

Droplet-based biomolecular arrays form the basis for a new class of bioinspired material system, whereby decreasing the sizes of the droplets and increasing the number of droplets can lead to higher functional density for the array. In this paper, we report on a non-microfluidic approach to form and connect nanoliter-to-femtoliter, lipid-coated aqueous droplets in oil to form micro-droplet interface bilayers (μDIBs). Two different modes of operation are reported for dispensing a wide range of droplet sizes (2–200μm radius). Due to the high surface-area-to-volume ratios of microdroplets at these length scales, droplet shrinking is prominent, which affects the stability and lifetime of the bilayer. To better quantify these effects, we measure the shrinkage rates for 8 different water droplet/oil compositions and study the effect of lipid placement and lipid type on morphological changes to μDIBs.


2016 ◽  
Vol 75 (2) ◽  
pp. 350-357
Author(s):  
Graham Dawson ◽  
Wei Chen ◽  
Luhua Lu ◽  
Kai Dai

The adsorption properties of two nanomorphologies of trititanate, nanotubes (TiNT) and plates (TiNP), prepared by the hydrothermal reaction of concentrated NaOH with different phases of TiO2, were examined. It was found that the capacity for both morphologies towards methylene blue (MB), an ideal pollutant, was extremely high, with the TiNP having a capacity of 130 mg/g, higher than the TiNT, whose capacity was 120 mg/g at 10 mg/L MB concentration. At capacity, the well-dispersed powders deposit on the floor of the reaction vessel. The two morphologies had very different structural and adsorption properties. TiNT with high surface area and pore volume exhibited exothermic monolayer adsorption of MB. TiNP with low surface area and pore volume yielded a higher adsorption capacity through endothermic multilayer adsorption governed by pore diffusion. TiNP exhibited a higher negative surface charge of −23 mV, compared to −12 mV for TiNT. The adsorption process appears to be an electrostatic interaction, with the cationic dye attracted more strongly to the nanoplates, resulting in a higher adsorption capacity and different adsorption modes. We believe this simple, low cost production of high capacity nanostructured adsorbent material has potential uses in wastewater treatment.


2021 ◽  
Author(s):  
Nuray Kizildag

Ceramic materials are well known for their hardness, inertness, superior mechanical and thermal properties, resistance against chemical erosion and corrosion. Ceramic nanofibers were first manufactured through a combination of electrospinning with sol–gel method in 2002. The electrospun ceramic nanofibers display unprecedented properties such as high surface area, length, thermo-mechanical properties, and hierarchically porous structure which make them candidates for a wide range of applications such as tissue engineering, sensors, water remediation, energy storage, electromagnetic shielding, thermal insulation materials, etc. This chapter focuses on the most recent advances in the applications of ceramic nanofibers.


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