Oxidizing agent impacting on growth of ZnO tetrapod nanostructures and its characterization.

In this paper, the fabrication of ZnO tetrapod was investigated. It was synthesized by the thermal oxidation technique using metal zinc powder mixed with oxidizing agents such as hydrogen peroxide (H2O2) and ammonium persulfate ((NH4)2S2O8). The furnace heating temperature reached at 1000 °C in the air. The average diameter and length of a tetrapod leg for mixture with H2O2 from SEM were 45.3 nm and 1.57 µm, respectively. The oxygen vacancy (36%) of ZnO tetrapod with H2O2 was higher than 33% of ZnO tetrapod with only Zn. Growth mechanism of ZnO tetrapod was processed via the formation of Zn nucleus and growing the wurtzite structure. The growing directions of ZnO crystal conformed with the [0001] direction. ZnO tetrapod showed up the high resolution TEM image with the lattice spacing 0.252 nm. From these results, this work was indicated that H2O2 solution was a better oxidizing reaction helper to make ZnO tetrapod nanostructures than anything else.

Synthesis of hierarchically structured ɤ-Fe2O3-PPy nanocomposite as effective adsorbent for cationic dye removal from wastewater.

Industrial dye effluents, which are a major wastage component that enter the natural environment, pose a significant health risk to human and aquatic life. Therefore, the effective removal of dye effluents is a major concern. Against this backdrop, in this study, a low-cost, earth-abundant, and ecofriendly ɤ-Fe2O3-PPy nanocomposite was prepared employing the conventional hydrothermal method. The morphology, functional groups, and elemental composition of ɤ-Fe2O3-PPy were characterized by XRD, SEM, XPS, and FTIR studies. Under optimized conditions, the prepared novel ɤ-Fe2O3-PPy nanocomposite showed a high methylene blue (MB) adsorption capacity of 464 mg/g, which is significantly higher than that of existing adsorbents such as CNTs and polymer-modified CNTs. The adsorption parameters such as pH, adsorbent dosage, and ionic strength were optimized to enhance the MB adsorption capacity. The adsorption results revealed that MB is adsorbed onto the adsorbent surface via electrostatic interactions, hydrogen bonding, and chemical binding interactions. In terms of practical application, the adsorbent's adsorption-desorption ability in conjunction with magnetic separation was investigated; the prepared ɤ-Fe2O3-PPy nanocomposite exhibited excellent adsorption and desorption efficiencies over more than seven adsorption-desorption cycles.