Elaboration of porous alumina nanofibers by electrospinning and molecular layer deposition for organic pollutant removal

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.

N-Doped HNT/TiO2 Nanocomposite by Electrospinning for Acetaminophen Degradation

In this study, we combined electrospinning of a large amount of halloysite (HNT, 95%) with nitriding to produce N-HNT-TiO₂ composite nanofibers (N-H95T5 hereafter) to be used for acetaminophen (ACT) photodegradation. Investigation of the morphological and structural properties of the obtained materials did not highlight any significant difference in their morphological features and confirmed that nitrogen was evenly distributed in the samples. Photocatalytic tests under visible light showed that acetaminophen photodegraded faster in the presence of samples with nitrogen (N-H95T5) than without (H95T5 nanofibers). Moreover, the N-H95T5 nanocomposite photocatalytic activity did not change after repeated utilization (five cycles). The addition of scavengers during photocatalytic tests showed the key implication of OH^•-, O₂^•- and h⁺ radicals in acetaminophen degradation. These results indicated that N-H95T5 composite nanofibers could be considered a cheap multifunctional material for photodegradation and could open new prospects for preparing tunable photocatalysts.

α and γ Alumina Spheres for Azo Dye (Allura Red) Removal from Aqueous Media

Allura red or Red 40 (R40) is a dye widely used in the food, textile, and pharmaceutical industries; it is considered dangerous because it is soluble in water, and it has high toxicity and resistance to natural degradation. Several advanced wastewater treatments have been shown to be effective for R40 removal but some of them present disadvantages such as by-products obtention, high energy consumption, and high cost of the reactants used in the removal process. In the present work, α-Alumina (Alu) and γ-Alu spheres were synthesized by the encapsulation method. The prepared spheres were characterized by FT-IR, XRD, SEM/EDS, and SBET, and it was determined the presence of only inorganic bonds from ceramic material, and the amorphous alumina was observed in spheres with a smooth and uniform surface and with pores. R40 adsorption kinetics and isotherms were performed, as well as material regeneration for consequent sorption cycles. Sorption tests for R40 removal were carried out under different conditions of initial concentration, pH value, and the presence of interfering ions. The maximal sorption capacity of the synthetized α- and γ-Alu spheres were situated between 0.1765 and 18.9865 mg/g. Different kinetic and isothermal equations were applied and finally, the experimental data was described by Elovich and Freundlich models. The γ-Alu spheres after five heat treatment regeneration cycles showed stable behavior and potential re-use in new sorption processes with R40 removal >97.7% at pH 3 and >85.6% at $C_0$  =10 mg/L. The obtained results showed that the γ-Alu spheres are novel, alternative, and sustainable synthesized materials for the advanced treatment of wastewater by adsorption process for the removal of Allura red azo dye in aqueous media.