Abstract:Chitosan is a natural polymer that has been widely utilized for many purposes in the food, textile, agriculture, water treatment, cosmetic and pharmaceutical industries. Based on its characteristics, including biodegradability, non-toxicity and antimicrobial properties, it has been employed effectively in wound healing applications. Importantly, however, it is necessary to improve chitosan's capacities by combination with zinc oxide (ZnO), titanium dioxide (TiO 2 ) and silver (Ag) nanoparticles (NPs). In this review of many of the latest research papers, we take a closer look at the antibacterial effectiveness of chitosan combined with ZnO, TiO 2 and Ag NPs and also evaluate the specific wound healing application potentials.

Microalgae have been considered as one of the most promising biomass feedstocks for various industrial applications such as biofuels, animal/aquaculture feeds, food supplements, nutraceuticals, and pharmaceuticals. Several biotechnological challenges associated with algae cultivation, including the small size and negative surface charge of algal cells as well as the dilution of its cultures, need to be circumvented, which increases the cost and labor. Therefore, efficient biomass recovery or harvesting of diverse algal species represents a critical bottleneck for large-scale algal biorefinery process. Among different algae harvesting techniques (e.g., centrifugation, gravity sedimentation, screening, filtration, and air flotation), the flocculation-based processes have acquired much attention due to their promising efficiency and scalability. This review covers the basics and recent research trends of various flocculation techniques, such as auto-flocculation, bio-flocculation, chemical flocculation, particle-based flocculation, and electrochemical flocculation, and also discusses their advantages and disadvantages. The challenges and prospects for the development of eco-friendly and economical algae harvesting processes have also been outlined here.

To enhance the performance of lithium-ion batteries, zinc oxide (ZnO) has generated interest as an anode candidate owing to its high theoretical capacity. However, because of its limitations such as its slow chemical reaction kinetics, intense capacity fading on potential cycling, and low rate capability, composite anodes of ZnO and other materials are manufactured. In this study, we introduce binary and ternary composites of ZnO with other metal oxides (MOs) and carbon-based materials. Most ZnO-based composite anodes exhibit a higher specific capacity, rate performance, and cycling stability than a single ZnO anode. The synergistic effects between ZnO and the other MOs or carbon-based materials can explain the superior electrochemical characteristics of these ZnO-based composites. This review also discusses some of their current limitations.

No abstract

No abstract

Titanium dioxide nanoparticles (TiO2 NPs) have some limitations, such as their low surface area, high bandgap energy, and low recycling ability. To overcome these limitations, TiO2 can be prepared in microscale/macroscale structures. TiO2 microscale structures, in comparison with TiO2 nanopowder, have higher surface areas, more tunable pore structures, and better top photocatalytic activity. In contrast, for TiO2 macroscale structures, although the surface area is lower than TiO2 nanopowder in many cases, they still achieve similar or better photocatalytic performance due to their unique properties. Moreover, both TiO2 microscale and macroscale structures can be easily recovered from reaction media. The difference between these two types of TiO2 structures is a function not only of size but also of the preparation process. Every type of TiO2 structure has its own advantages and disadvantages, as will be discussed further in the following pages. Future perspectives on this research field also will be discussed.

No abstract

MgAC-Fe 3 O 4 /TiO 2 hybrid nanocomposites were synthesized in different ratios of MgAC-Fe 3 O 4 and TiO 2 precursor. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray fluorescence spectrometry (XRF), electron spin resonance spectrometry (ESR), Brunauer-Emmett-Teller (BET), photoluminescence (PL), and UV photoelectron spectroscopy (UPS) were used to characterize the nanocomposites. The increase of MgAC-Fe 3 O 4 , in the hybrid nanocomposites’ core-shell structure, led to the decrease of anatase TiO 2 peaks, thus reducing the photo-Fenton and photocatalytic activities. According to the obtained data, MgAC-Fe 3 O 4 [0.05 g]/TiO 2 showed the best photo-Fenton and photocatalytic activities, having removed ~93% of MB (photo-Fenton reaction) and ~80% of phenol (photocatalytic reaction) after 20 and 80 mins, respectively. On the pilot scale (30 L), MgAC-Fe 3 O 4 [0.05 g]/TiO 2 was completely removed after 27 and 30 hours by the photo-Fenton and photocatalytic activities, respectively. The synergistic effect gained from the combined photo-Fenton and photocatalytic activities of Fe 3 O 4 and TiO 2 , respectively, was credited for the performances of the MgAC-Fe 3 O 4 /TiO 2 hybrid nanocomposites.