Modified alumina nanofiber membranes for protein separation

Alumina Ceramic Nanofibers: An Overview of the Spinning Gel Preparation, Manufacturing Process, and Application

As an important inorganic material, alumina ceramic nanofibers have attracted more and more attention because of their excellent thermal stability, high melting point, low thermal conductivity, and good chemical stability. In this paper, the preparation conditions for alumina spinning gel, such as the experimental raw materials, spin finish aid, aging time, and so on, are briefly introduced. Then, various methods for preparing the alumina ceramic nanofibers are described, such as electrospinning, solution blow spinning, centrifugal spinning, and some other preparation processes. In addition, the application of alumina ceramic nanofibers in thermal insulation, high-temperature filtration, catalysis, energy storage, water restoration, sound absorption, bioengineering, and other fields are described. The wide application prospect of alumina ceramic nanofibers highlights its potential as an advanced functional material with various applications. This paper aims to provide readers with valuable insights into the design of alumina ceramic nanofibers and to explore their potential applications, contributing to the advancement of various technologies in the fields of energy, environment, and materials science.

Wetting Property Modification of Al2O3 by Helium Ion Irradiation: Effects of Beam Energy and Fluence on Contact Angle

In imparting wetting properties, a fabrication process without the addition of new compounds and deposition of coating layers would be the most desirable because it does not introduce additional complexities. Hence, the ion beam irradiation technique is used as it enables the chemistry of materials to be modified through simple adjustments of irradiation parameters such as the type of accelerated particles, beam energy, and fluence. In this study, the hydrophilicity of alumina surfaces was weakened by irradiating He ion beams of different energy levels (200 keV and 20 MeV). These transitions become more pronounced as the total beam fluence increases. In low-energy irradiation, the effect of irradiation is predominant near the surface, and hydrophilicity is weakened by the increase in carbon adsorption and suppression of dissociative adsorption of water molecules owing to the introduction of oxygen vacancies. In contrast, nuclear transmutations are induced by irradiation with high-energy beams. Consequently, fluorine is generated, and hydrophobic functional groups are formed on the surface. By varying the beam conditions, the wetting properties of the target ceramic can be controlled to the desired level, which is required in various industries, via appropriate adjustments of the beam parameters. In addition, the beam irradiation technique may be applicable to all ceramic materials, including lattice oxygen and alumina.

Selective Adsorption and Separation of Proteins by Ligand-Modified Nanofiber Fabric

Electrospun polyvinyl alcohol (PVA) nanofiber fabric was modified by Cibacron Blue F3GA (CB) to enhance the affinity of the fabric. Batch experiments were performed to study the nanofiber fabric's bovine hemoglobin (BHb) adsorption capacity at different protein concentrations before and after modification. The maximum BHb adsorption capacity of the modified nanofiber fabric was 686 mg/g, which was much larger than the 58 mg/g of the original fabric. After that, the effect of feed concentration and permeation rate on the dynamic adsorption behaviors for BHb of the nanofiber fabric was investigated. The pH impact on BHb and bovine serum albumin (BSA) adsorption was examined by static adsorption experiments of single protein solutions. The selective separation experiments of the BHb-BSA binary solution were carried out at the optimal pH value, and a high selectivity factor of 5.45 for BHb was achieved. Finally, the reusability of the nanofiber fabric was examined using three adsorption-elution cycle tests. This research demonstrated the potential of the CB-modified PVA nanofiber fabric in protein adsorption and selective separation.

Effective separation of water-DMSO through solvent resistant membrane distillation (SR-MD)

The treatment of organic waste or wastewater with high organic solvent content has been challenging in industries as it cannot be done effectively using conventional wastewater treatment technologies such as biodegradation and advanced oxidation process. Solvent resistant membrane distillation (SR-MD) was proposed as an energy-efficient alternative to treat these waste streams but its application is hampered by the lack of solvent-resistant membranes, and there is a research gap in studying the feeds with water-solvent mixtures. In this work, ceramic tubular membranes with different pore sizes and structures were molecularly grafted with 1H,1H,2H,2H-perfluorodecyltriethoxysilane to obtain hydrophobic ceramic membranes for SR-MD. The modified membranes exhibited excellent hydrophobicity and solvent resistant properties, and they were tested for SR-MD performance with a wide range of dimethyl sulfoxide (DMSO) feed concentrations, from 3.5 to 85 wt%. The membranes exhibited a high DMSO rejection of >98% and the separation factor of >170, with permeation flux >4.4 kg m^-2 h^-1 when the DMSO concentration in feed was below 65 wt%. The separation performance was found strongly dependent on the evaporation step and the vapour-liquid equilibrium near the interface. The DMSO rejection was also comparable to pervaporation while the permeation flux was much higher at the feed concentration of 50 wt%. This study establishes the strategy of using SR-MD as a promising membrane process in treating complex industrial wastes with high organic solvent content.

Preparation of Alumina Nanorods from Chromium-Containing Alumina Sludge

Alumina nanorods were prepared from chromium-containing alumina sludge, and the effects of doping elements, such as Cr, Fe, and Mg, were researched. The results show that the crystal transformation of alumina is restricted by the doped Cr and facilitated by the doped Fe and Mg, which is transformed from θ-Al₂O₃ to α-Al₂O₃ in the calcination process. Meanwhile, the crystal transformation of alumina is strongly restrained by co-doped elements from the chromium-containing alumina sludge. The doped elements change the course of phase structure transformation and slightly transform the chemical bond of the alumina nanorods. The impure elements are doped in the alumina crystal and restrain the crystalline growth of alumina nanorods according to the rules. In the sample prepared from chromium-containing alumina sludge, more Cr and Mg but fewer Fe are doped, and most Cr are existed as Cr(III). It is possible that the Fe-doping is confined by the competition of Cr and Mg. Moreover, the lattice imperfection of alumina is caused by doped ions, such as Cr, Fe, and Mg, and the chemical state of O and Al are affected. The findings by these experiments provide essential information for eliminating pollution and promoting comprehensive utilization of the chromium-containing alumina sludge.

Covalent Surface Modification of Silicon Oxides with Alcohols in Polar Aprotic Solvents

Alcohol-based monolayers were successfully formed on the surfaces of silicon oxides through reactions performed in polar aprotic solvents. Monolayers prepared from alcohol-based reagents have been previously introduced as an alternative approach to covalently modify the surfaces of silicon oxides. These reagents are readily available, widely distributed, and are minimally susceptible to side reactions with ambient moisture. A limitation of using alcohol-based compounds is that previous reactions required relatively high temperatures in neat solutions, which can degrade some alcohol compounds or could lead to other unwanted side reactions during the formation of the monolayers. To overcome these challenges, we investigate the condensation reaction of alcohols on silicon oxides carried out in polar aprotic solvents. In particular, propylene carbonate has been identified as a polar aprotic solvent that is relatively nontoxic, readily accessible, and can facilitate the formation of alcohol-based monolayers. We have successfully demonstrated this approach for tuning the surface chemistry of silicon oxide surfaces with a variety of alcohol containing compounds. The strategy introduced in this research can be utilized to create silicon oxide surfaces with hydrophobic, oleophobic, or charged functionalities.

Antifungal activity of fabricated mesoporous alumina nanoparticles against root rot disease of tomato caused by Fusarium oxysporium

BACKGROUND

The present work involved the synthesis and characterisation of mesoporous alumina sphere (MAS) nanoparticles to evaluate their biological activity against tomato root rot caused by Fusarium oxysporium, as compared with the recommended fungicide, tolclofos-methyl, under laboratory and greenhouse conditions. The effects of MAS nanoparticles on the growth of tomato plants were also evaluated and compared with those of tolclofos-methyl.

RESULTS

The physical characteristics and structural features of MAS nanoparticles, such as their large surface-area-to-volume ratio, active surface sites and open channel pores, caused high antifungal efficacy against F. oxysporium. MAS nanoparticles presented an antifungal potential similar to that of tolclofos-methyl and much greater than that of the control under both laboratory and greenhouse conditions. The highest growth parameters were recorded in tomato plants treated with MAS nanoparticles, followed by those treated with tolclofos-methyl.

CONCLUSIONS

Our study demonstrated the possible use of cylindrically cubic MAS nanoparticles as an effective alternative for the control of Fusarium root rot in tomato. © 2016 Society of Chemical Industry.

Green synthesis and antifungal activity of Al2O3NPs against fluconazole-resistant Candida spp isolated from a tertiary care hospital

Antifungal activity of ecofriendly and cost effectively prepared Al₂O₃NPs onCandia alibicans.

Synthesis and characterization of poly(γ-glutamic acid)-based alumina nanoparticles with their protein adsorption efficiency and cytotoxicity towards human prostate cancer cells

Protein adsorption and cytotoxicity of poly(γ-glutamic acid) functionalized nanoalumina.

Ultrathin γ-Al2O3 nanofibers with large specific surface area and their enhanced thermal stability by Si-doping

Ultrathin boehmite nanofibers were synthesized via a parallel flow co-precipitation method and then transformed into γ-Al₂O₃ nanofibers by calcination.