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Phenol is a priority pollutant that presents a significant threat to human health and natural systems when discharged directly into the environment. Consequently, numerous technologies have been used and developed to eliminate phenol from wastewater streams. These technologies can be categorized into physical, chemical, and biological methods. While conventional treatment methods are highly efficient in phenol removal; some of these techniques are not environmentally friendly and others are expensive. Therefore, sustainable, and green technologies are being employed and taken into consideration in the treatment of phenol wastewater due to their effectiveness, affordability, and environmental compatibility. This review aims to highlight efficient green physiochemical and biological methods of water treatment and demonstrate the mechanisms of phenol removal in these technologies. Particular emphasis will be given to the use of low-cost adsorbents prepared from industrial and agricultural wastes for the efficient removal of phenol from wastewater as adsorption processes show the highest cost-effectiveness among all the treatment technologies. [ABSTRACT FROM AUTHOR]

The current study investigated the structural, mechanical, electronic, and optical properties of new perovskite hydrides XSnH 3 (X = Rb, Cs, and Fr) for hydrogen storage applications using a first-principles study with the GGA-PBE approach. The calculated lattice constants form optimized cubic crystal have 4.40 Å, 4.49 Å and 4.53 Å for RbSnH 3 , CsSnH 3 , and FrSnH 3 hydrides, respectively. These materials were found to be thermodynamically and mechanically stable structures owing to their negative cohesive energy and elastic constants. Additionally, molecular dynamics (MD) calculations were performed to study the thermal stability of the current materials. These results indicate that the considered materials were stable and exhibited no structural deformation. The electronic band structure and density of states confirmed that the current materials exhibit metallic behavior via overlapping of the valence and conduction bands with a zero-energy band gap. It was found these compounds have anisotropic and rigid in nature. The Poisson's ratio, Pugh's ratio (B/G), and Cauchy pressure (C P) values indicate that the current compounds have ionic bonding and brittle behavior. Different optical parameters were calculated for these materials, such as the conductivity, dielectric function, loss energy, refractive index, and adsorption. Interestingly, these optical parameters indicate that XSnH 3 is promising for optoelectronic, photonic, and energy storage applications. Finally, the calculated hydrogen storage capacities for RbSnH 3, CsSnH 3, and FrSnH 3 are 1.45 wt%, 1.18 wt %, and 0.87 wt %respectively. These results show that current materials have the potential and promise for hydrogen storage applications, and devices. [Display omitted] • Three novel perovskite hydrides are examined for hydrogen storage using DFT. • XSnH 3 (X = Rb, Cs, and Fr) hydrides are mechanically and thermodynamically stable. • XSnH 3 perovskites are metallic in nature. • Hydrogen storage capacities of XSnH 3 (X = Rb, Cs, and Fr) hydrides are 1.45 wt%, 1.18 wt %, and 0.87 wt %respectively. [ABSTRACT FROM AUTHOR]

We conducted a comprehensive investigation into the structural, mechanical, electronic, magnetic, thermodynamic, optical, and hydrogen storage properties of the novel XScH 3 (X: Ca and Mg) perovskite hydrides by using density functional theory (DFT). Our calculations of the cohesive energy and elastic constants demonstrated that XScH 3 compounds exhibit both thermal and mechanical stability. The metallic nature of current materials is based on the investigation of the electronic band structure and total density states. The analysis of Pugh's ratio (B/G) indicated that these hydrides were ductile materials. Furthermore, it was found that their bonding type was primarily ionic. These substances have been classified as conductors with antiferromagnetic qualities in terms of their magnetic properties. Furthermore, these materials exhibited promising effects on optical properties such as conductivity, absorption, dielectric function, and refractive index. Our predictions revealed that CaScH 3 was found to be optically superior hydride. The dynamic stability of these crystals was assessed by analyzing their phonon dispersion curves and by molecular dynamics simulations. Additionally, we studied their thermal properties, including heat capacity, entropy, energy, and free energy, as functions of temperature. Furthermore, our study investigated the hydrogen storage capacity of XScH 3 compounds, with CaScH 3 and MgScH 3 , demonstrating hydrogen storage capacities of 3.43 wt% and 4.18 wt%, respectively. This study marks the first exploration of XScH 3 perovskite hydrides and offers new options for hydrogen storage materials. • Three novel perovskite hydrides are examined for hydrogen storage using DFT. • XScH 3 (X: Ca and Mg) hydrides are mechanically and thermodynamically stable. • XScH 3 perovskites are metallic in nature. • Hydrogen storage capacities of XScH 3 (X: Ca and Mg) hydrides are 3.43 wt% and 4.18 wt%, respectively. [ABSTRACT FROM AUTHOR]