Chelation ion chromatography of alkaline earth and transition metals a using monolithic silica column with bonded N-hydroxyethyliminodiacetic acid functional groups

Bridging Hydrometallurgy and Biochemistry: A Protein-Based Process for Recovery and Separation of Rare Earth Elements

The extraction and subsequent separation of individual rare earth elements (REEs) from REE-bearing feedstocks represent a challenging yet essential task for the growth and sustainability of renewable energy technologies. As an important step toward overcoming the technical and environmental limitations of current REE processing methods, we demonstrate a biobased, all-aqueous REE extraction and separation scheme using the REE-selective lanmodulin protein. Lanmodulin was conjugated onto porous support materials using thiol-maleimide chemistry to enable tandem REE purification and separation under flow-through conditions. Immobilized lanmodulin maintains the attractive properties of the soluble protein, including remarkable REE selectivity, the ability to bind REEs at low pH, and high stability over numerous low-pH adsorption/desorption cycles. We further demonstrate the ability of immobilized lanmodulin to achieve high-purity separation of the clean-energy-critical REE pair Nd/Dy and to transform a low-grade leachate (0.043 mol % REEs) into separate heavy and light REE fractions (88 mol % purity of total REEs) in a single column run while using ∼90% of the column capacity. This ability to achieve, for the first time, tandem extraction and grouped separation of REEs from very complex aqueous feedstock solutions without requiring organic solvents establishes this lanmodulin-based approach as an important advance for sustainable hydrometallurgy.

Optimization of copper detection based on polarization-resolved laser-induced breakdown spectroscopy

In order to obtain stable spectral data of copper plasma, a detection platform of polarization-resolved laser-induced breakdown spectroscopy (PRLIBS) was built. The PRLIBS characteristic function of copper was constructed by combining the spectral path of plasma discrete spectrum and contact spectrum. The system can not only measure the original data, but also obtain the polarization information in the spectral data. By analyzing the extraction method of spatial polarized light information, the characteristic model of S-wave intensity information in PRLIBS was derived. The results show that in the decay process of plasma energy, the anisotropy of plasma recombination under local thermal equilibrium makes the number of deflected particles of atoms and electrons different in unit time, which leads to the polarization of radiation. The polarization characteristics of the plasma spectrum decreased with the increase of laser energy density. The S-wave was very active, and the polarization of continuous media was much stronger than that of discrete line emission. The advantages were helpful to obtain more stable characteristic peak signals. As a plasma element identification method, PRLIBS makes up for the deficiency of plasma detection technology, and can provide a scientific basis for the safety and non-destructive detection of heavy metals.

Water-Soluble Carbon Quantum Dots Modified by Amino Groups for Polarization Fluorescence Detection of Copper (II) Ion in Aqueous Media

Industrialization is serious for changing the environment and natural water composition, especially near cities and manufacturing areas. Logically, the new ultrasensitive technology for precise control of the quality and quantity of water sources is needed. Herein, an innovative method of polarization fluorescence analysis (FPA) was developed to measure the concentration of heavy metals in water. The approach was successfully applied for precise tests with reduced analysis time and increased measurement efficiency among laboratory methods. Based on this work, the investigations established the new type of carbon quantum dots (CQDs) with controllable fluorescence properties and functionalized amino—groups, which is appropriate for FPA. The parameters of one and two-step microwave synthesis routes are adjusted wavelength and fluorescence intensity of CQDs. Finally, under optimized conditions, the FPA is showed the detection of copper (2+) cations in water samples below European Union standard (2 mg/L). Moreover, in comparison with fluorescence quenching, polarization fluorescence is proved as a convenient, simple, and rapid test method for effective water safety analysis.

A facile size tunable one-pot synthesis of dipicolinate@nZVI core–shell nanoparticles: material properties for trace cadmium ion removal

Dipicolinic acid capped iron nanoparticles were obtained by a facile one-pot chemical synthesis and the ellipsoidal forms of PDCA@nZVI nanoparticles showed enhanced adsorption of cadmium ions at trace levels.

Recent Progress in Monolithic Silica Columns for High-Speed and High-Selectivity Separations

Monolithic silica columns have greater (through-pore size)/(skeleton size) ratios than particulate columns and fixed support structures in a column for chemical modification, resulting in high-efficiency columns and stationary phases. This review looks at how the size range of monolithic silica columns has been expanded, how high-efficiency monolithic silica columns have been realized, and how various methods of silica surface functionalization, leading to selective stationary phases, have been developed on monolithic silica supports, and provides information on the current status of these columns. Also discussed are the practical aspects of monolithic silica columns, including how their versatility can be improved by the preparation of small-sized structural features (sub-micron) and columns (1 mm ID or smaller) and by optimizing reaction conditions for in situ chemical modification with various restrictions, with an emphasis on recent research results for both topics.

Enhancement mechanisms behind exclusive removal and selective recovery of copper from salt solutions with an aminothiazole-functionalized adsorbent

The aminothiazole-functionalized adsorbent (CEAD) could exclusively remove and to selectively recover copper. The adsorption and separation properties of Cu(II) onto CEAD from aqueous media, with or without salts such as NaNO3, Ca(NO3)2 and Ni(NO3)2, were systematically compared by carrying out single, binary and multiple component static and dynamic experiments. In binary systems, the adsorption capacities of Cu(II) were obviously increased by 39.47%, 47.37% and 57.89% with Ni(NO3)2, NaNO3 and Ca(NO3)2, respectively. Besides, simulation study was performed to selectively recover Cu(II) from multi-component aqueous media, with the separation factor of only 54.91 in aqueous media without salts. The separation factor became infinite in the presence of NaNO3 and the enhancement ratio for Cu(II) was raised by 126.31%. Dynamic adsorption could separate Cu(II) and Ni(II) completely and the amount of effluent for pure Ni(II) increased to 127 BV with the help of NaNO3. In the predominant chelating mode simulated by density functional theory calculation, a metal ion coordinated with three nitrogen atoms and formed a chelating complex with two five-membered rings, and Cu(II) showed stronger coordinating ability than Ni(II) did. Meanwhile, anions exerted significant beneficial effects by electrostatic screening, and thus strengthened the exclusive removal and selective recovery of Cu(II).