Green Synthesis of Magnetite Nanoparticles Using Aqueous Leaves Extracts of <i>Azadirachta indica</i>and Its Application for the Removal of As(V) from Water

Because of various disadvantages of chemical synthesis processes, these days people are attracting towards green synthesis processes as it is devoid of toxic by-products, cost-effective and eco-friendly. In this study, a simple green synthesis method is applied for the synthesis of magnetite (Fe3O4) nanoparticles (MNPs) by co-precipitation of FeCl3·6H2O and FeSO4·7H2O in the molar ratio of 2:1 using Azadirachta indica leaves extract under nitrogen environment. FTIR, XRD, SEM etc. were used to characterize the synthesized MNPs. Batch adsorption experiments were carried out to determine adsorption equilibrium of As(V) as a function of pH, adsorbent dose, contact time and different initial concentrations. Kinetics results were best described by pseudo-second order model with rate constant value 0.0052 g/(mg·min). The equilibrium adsorption isotherm was best fitted with Langmuir adsorption isotherm model. The maximum adsorption capacity was found to be 62.89 mg/g at pH 2. MNPs showed a high affinity for As(V) and avoids filtration for solid-liquid separation, thus it would be employed as a promising material for the removal of As(V) from water.

Electron–phonon physics from first principles using the EPW code

EPW is an open-source software for ab initio calculations of electron–phonon interactions and related materials properties.The code combines density functional perturbation theory and maximally localized Wannier functions to efficiently compute electron–phonon coupling matrix elements,and to perform predictive calculations of temperature-dependent properties and phonon-assisted quantum processes in bulk solids and low-dimensional materials.Here,we report on significant developments in the code since 2016,namely:a transport module for the calculation of charge carrier mobility under electric and magnetic fields using the Boltzmann transport equation;a superconductivity module for calculations of phonon-mediated superconductors using the anisotropic multi-band Eliashberg theory;an optics module for calculations of phonon-assisted indirect transitions;a module for the calculation of small and large polarons without supercells;and a module for calculating band structure renormalization and temperature-dependent optical spectra using the special displacement method.For each capability,we outline the methodology and implementation and provide example calculations.