Mechanistic insights into electric field-assisted nanofiltration for efficient lithium-magnesium separation.

Lithium, a pivotal resource in the new energy sector, demands the development of efficient and energy-saving lithium-magnesium separation technologies. This study employed electric field-assisted nanofiltration (E-NF) technology to achieve efficient lithium-magnesium separation. Compared with conventional nanofiltration, at a current density of 2 mA·cm, the rejection rate of Li⁺ decreased from -27.

The impact of stoichiometry on the initial steps of crystal formation: Stability and lifetime of charged triple-ion complexes.

Minerals form in natural systems from solutions with varying ratios of their lattice ions, yet non-stoichiometric conditions have generally been overlooked in investigations of new formation (nucleation) of ionic crystals. Here, we investigated the influence of cation:anion ratio in the solution on the initial steps of nucleation by studying positively and negatively charged triple ion complexes and subsequent particle size evolution. Our model systems are carbonates and sulfates of calcium and barium, as it was recently shown that solution stoichiometry affects the timing and rate of their nucleation.

A Database of Solution Additives Promoting Mg Dehydration and the Onset of MgCO Nucleation.

Formed via aqueous carbonation of Mg ions, the crystallization of magnesite (MgCO) is a promising route to carbon capture and reuse, albeit limited by the slow precipitation of MgCO. Although magnesite is naturally abundant, forming at low temperature conditions, its industrial production is an energy-intensive process due to the temperatures required to prevent the formation of hydrated phases. The principal difficulty in aqueous conditions arises from the very strong Mg···HO interaction, with high barriers to Mg dehydration.

Density functional theory based molecular dynamics study of solution composition effects on the solvation shell of metal ions.

We present an ab initio molecular dynamics study of the alkali metal ions Li+, Na+, K+ and Cs+, and of the alkaline earth metal ions Mg2+ and Ca2+ in both pure water and electrolyte solutions containing the counterions Cl- and SO42-. Simulations were conducted using different density functional theory methods (PBE, BLYP and revPBE), with and without the inclusion of dispersion interactions (-D3). Analysis of the ion-water structure and interaction strength, water exchange between the first and second hydration shell, and hydrogen bond network and low-frequency reorientation dynamics around the metal ions have been used to characterise the influence of solution composition on the ionic solvation shell.

Mechanism of Photoinduced Triplet Intermolecular Hydrogen Transfer between Cycloxydim and Chlorothalonil.

The possible reaction mechanisms for the experimentally observed hydrogen transfer between the herbicide cycloxydim (CD) and the triplet fungicide chlorothalonil (CT) were identified with density functional theory (DFT) and time-dependent density function theory (TDDFT) computations. Excited energy transfer (EET) calculations indicate that reactants for intermolecular hydrogen transfer were formed via energy transfer from triplet CT to ground state CD. Three possible reaction pathways after EET were identified, and hydrogen transfer from the hydroxyl group on the cyclohexane ring of CD to CT exhibited the lowest energy barrier.

Can small hydrophobic gold nanoparticles inhibit β₂-microglobulin fibrillation?

Inorganic nanoparticles stabilized by a shell of organic ligands can enhance or suppress the natural propensity of proteins to form fibrils. Functionalization facilitates targeted delivery of the nanoparticles to various cell types, bioimaging, drug delivery and other therapeutic and diagnostic applications. In this study, we provide a computational model of the effect of a prototypical thiol-protected gold nanoparticle, Au₂₅L₁₈(-) (L = S(CH₂)₂Ph) on the β₂-microglobulin natural fibrillation propensity.

Proposed alteration of images of molecular orbitals obtained using a scanning tunneling microscope as a probe of electron correlation.

Scanning tunneling spectroscopy (STS) allows us to image single molecules decoupled from the supporting substrate. The obtained images are routinely interpreted as the square moduli of molecular orbitals, dressed by the mean-field electron-electron interaction. Here we demonstrate that the effect of electron correlation beyond the mean field qualitatively alters the uncorrelated STS images.

Peptide synthesis of gold nanoparticles: the early steps of gold reduction investigated by density functional theory.

Gold nanoparticles can be synthesized by reducing chloroaurate(III) ions in the presence of peptides. Here, such reduction for serine and tyrosine is studied by density functional theory including solvent effects. We find that the formation of chloroaurate complexes of these amino acids is thermodynamically viable and facilitates the reduction of Au(III), to a greater degree for tyrosine as found in experiments.

Visualizing electron correlation by means of ab initio scanning tunneling spectroscopy images of single molecules.

Scanning tunneling microscopy (STM) has been a fundamental tool to characterize many-body effects in condensed matter systems, from extended solids to quantum dots. STM of molecules decoupled from the supporting conductive substrate has the potential to extend STM characterization of many-body effects to the molecular world as well. In this paper, we describe a many-body tunneling theory for molecules decoupled from the STM substrate, and we report on the use of standard quantum chemical methods to calculate the quantities necessary to provide the "correlated" STM molecular image.

Structure of the gas-phase glycine tripeptide.

The structural preferences of the neutral gas-phase glycine tripeptide have been investigated using a variety of strategies including a hierarchy of electronic structure theory (encompassing HF/3-21G single-point energy calculation and geometry optimisation, B3LYP/6-31G(d) geometry optimisation and MP2/6-31+G(d) single-point energy calculation and/or geometry optimisation). The structures and relative stabilities of the 20 most stable conformers identified were verified by M05-2X and mPW2-PLYP-D calculations. The most stable conformer located has a folded gamma-turn structure, with an NH.