Gamma Irradiation-Assisted Synthesis of Silver Nanoparticle and Their Antimicrobial Applications: A Review

This review presents an introduction to the synthesis of silver nanoparticles (Ag-NPs) by gamma irradiation method. This method offers some benefits over the conventional methods because it provides fully reduced and highly pure nanoparticles free from by-products or chemical reducing agents, and is capable of controlling the particle size and structure. The nucleation and growth mechanism of metallic nanoparticles are also discussed. The competition between nucleation and growth process in the formation of nanoparticles can determine the size of nanoparticles which is influenced by certain parameters such as the choice of solvents and stabilizer, the precursor to stabilizer ratio, pH during synthesis, and absorbed dose. The present review, summarizes the gamma irradiation synthesis of Ag-NPs procedure, advantages, applications and their antibacterial properties.

Preparation of metallic cobalt powders by thermolysis of cobalt (II) acetate, oxalate and formate

The thermal decomposition of cobalt (II) formate, acetate, and oxalate was studied by synchronous thermal analysis. It is established that in all cases the final product is metallic cobalt. Thermogravi- metric analysis combined with differential scanning calorimetry and mass spectroscopy made it possi- ble to establish thermolysis schemes and gaseous products of salt decomposition. The conditions for obtaining powdered metallic cobalt from carboxylic acid salts are determined. It was determined by electron microscopy that the particle size and structure of metal powders depend on the type of initial salt.

Microwave-Assisted Synthesis of Zinc Oxide Nanoparticles on Paper

Nanostructured zinc oxide (ZnO) particles were grown on paper substrate made from Abaca hybrid 7 pulp. Microwave irradiation technique was used at power levels (180 and 540W) and exposure times (5, 10, 20 and 25 minutes). Chemical transformations were observed using Fourier Transform Infrared (FTIR) Spectroscopy. The effects of the power levels and exposure times on the morphology of the nanostructures were determined using scanning electron microscopy. FTIR spectra proved the embedment of ZnO on the paper substrate. Power levels and exposure times affected the distribution, particle size and structure of the ZnO nanoparticles. Higher power level and longer exposure resulted to the formation of more ZnO with larger particles. Grainlike and flowerlike ZnO nanostructures were formed at lower and higher levels, respectively.

Review of Research on Template Methods in Preparation of Nanomaterials

The nanomaterials have been widely used in various fields, such as photonics, catalysis, and adsorption, because of their unique physical and chemical properties. Therefore, their production methods are of utmost importance. Compared with traditional synthetic methods, the template method can effectively control the morphology, particle size, and structure during the preparation of nanomaterials, which is an effective method for their synthesis. The key for the template method is to choose different templates, which are divided into hard template and soft template according to their different structures. In this paper, the effects of different types of templates on the morphology of nanomaterials during their preparation are investigated from two aspects: hard template and soft template, combined with the mechanism of action.