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The goal of this study is to identify the optical, magnetic, and structural properties of alpha-Fe 2 O 3 /MgO & MgO/ alpha-Fe 2 O 3 nanocomposites and use them to purify water contaminated by harmful dyes. The economical hydrothermal approach was utilized to create nanocomposites, resulting in weight ratios of alpha-Fe 2 O 3 : MgO (1:1, 2:1 and 1:2). The synthesized materials containing alpha-Fe 2 O 3 and MgO phases were identified by XRD pattern. XPS spectra were used to identify lattice defects and oxygen vacancies. The magnetic investigations show that pure alpha-Fe 2 O 3 has a greater magnetic character than other synthesized materials, with a maximum magnetization of 0.14 x 10 -2 emu/gm. In just 90 min, alpha-Fe 2 O 3 /MgO nanocomposites degrade Rose Bengal dye by 90.01 %, demonstrating their superior photocatalytic activity. The combined action of alpha-Fe 2 O 3 and MgO, which prevents the formation of highly active radical species (OH center dot and O 2 center dot radicals) and photo -generated charge carrier recombination, is responsible for the increased photocatalytic activity. Furthermore, the magnetic nature of these nanocomposites enables them for the reusability process.

The present work reports the synthesis of pure and Zr-doped hematite nanoparticles from the thermally induced polymorphic transformation from magnetite nanoparticles. The microstructural phases and parameters of the nanoparticles were investigated with X-ray diffraction. It is found that transformation from magnetite to hematite is delayed with increasing Zr content. The absence of X-ray diffraction peaks related to metallic Zr and its oxide in the doped samples indicates the dopant was uniformly distributed in the host hematite matrix. Fourier transform infrared spectroscopy and diffuse reflectance spectroscopy were carried out to investigate the optical properties of the nanoparticle samples. The decrease in IR absorbance intensity and shifting of the absorption bands to a lower frequency was observed with Zr doping in hematite, indicating a reduction in crystallinity and substitutional doping with the host element, respectively. It was found that the Zr doping improves the visible light absorption and decreases the band gap of hematite nanoparticles. X-ray photoelectron spectroscopy results confirmed the + 4 oxidation state of Zr dopant in the host lattice, and Zr-doped hematite nanoparticles indicated a decrease in octahedral coordination with an increase in tetrahedral coordination of Fe3+ oxidation state. Room-temperature magnetic properties were investigated with the vibrating sample magnetometer. A significant improvement in photocatalytic properties of hematite was found with Zr doping.

In this study, pure and Y 3 + substituted Hematite (alpha-Fe 2 O 3 ) nanostructure with various compositions, alpha-Fe 2-x Y x O 3 (x = 0.00, 0.02, 0.05, 0.08 & 0.10), synthesized by using the Sol -Gel method. The X-ray diffraction (XRD) patterns of both pure and Y -substituted alpha-Fe 2 O 3 samples revealed a rhombohedral phase with the R 3 c space group, having crystallite sizes ranging from 23 to 48 nm. Moreover, the XRD findings align closely with Raman observations. The variation in grain size observed via FE-SEM correlates well with the crystallite size and strain determined by XRD measurements. The resistivity plots exhibited two distinct regions corresponding to two different conduction mechanisms. Analysis of the resistivity data suggests the presence of variable range hopping and nearest -neighbour hopping conduction mechanisms within temperature ranges of 100 K to 300 K and 300 K to 400 K, respectively. The dielectric and magnetic properties exhibit a fluctuating behaviour with the increasing concentration of the Y 3 + doping. We observed a shift towards weakly ferromagnetic conduct -like behaviour with the introduction of Y 3 + into the hematite nanostructures.

The need for pharmaceuticals for their use as medicines is rapidly increasing. Consequently, the pharmaceutical industries are springing up quickly to meet the demand. There are many factors that contribute to the production of increasingly inventive pharmaceuticals, including the continual progress of medicinal science, improvements in research and development, and large investments in healthcare. However, the widespread use of pharmaceuticals and their improper release into bodies of water have badly contaminated the water resources and consequently adversely affected the marine life. This is due to the high persistence of several pharmaceuticals and their metabolites, which prevent their breakdown for long time in the aquatic environments. The most common growing pharmaceutical contaminants are analgesics, β-blockers, lipid-lowering pharmaceuticals, antiepileptics, anti-inflammatories, and antibiotics. As a result, the degradation of emerging pharmaceutical pollutants in wastewater is one of the current major global concerns in order to meet the demand for safe water and safeguard aquatic life. Many techniques have been developed recently for pharmaceutical pollutants removal, but at the present time, the photocatalysis approach is the most efficient for eradicating newly emerging pharmaceutical contaminants. It is because the photocatalysis approach has various advantages such as the higher catalytic efficiencies, rapid reaction, no secondary hazardous products, low cost, reusable, complete degradation, and use of sustainable solar energy to trigger catalyst for pharmaceuticals eradication. Various visible light–driven photocatalysts for pharmaceutical pollutants degradation are explored in this chapter along with degradation reaction mechanisms and adverse effects of these pollutants.