Elemental distributions of solid waste collected from the germanium extraction process.

The solid waste produced from the germanium extraction process has attached much attention to its potential germanium sources. However, the elemental distribution of solid waste is still unclear. Therefore, the solid waste was studied using a sequential extraction procedure and characterizations including XRD, FTIR, XPS, SEM-EDS, and XAFS.

Immobilization mechanism of cesium in geopolymer: Effects of alkaline activators and calcination temperature.

Geopolymer is always regarded as a promising material for the immobilization of radioactive waste. In the present study, the stabilization of Cs in geopolymers activated by NaOH and NaSiO solutions and calcined at various temperatures was studied via toxicity characteristic leaching procedure (TCLP), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope and energy dispersive spectroscopy (SEM-EDS), solid-state nuclear magnetic resonance (SSNMR), and N adsorption-desorption isotherm. For both NaOH-activated and NaSiO-activated geopolymers, the leaching concentrations of Cs decreased with the increase of calcination temperature.

Influence of aluminate and silicate on selenate immobilization using alkaline-earth metal oxides and ferrous salt.

Effects of aluminate and silicate species on the SeO immobilization using alkali-earth metal oxides and ferrous species have not been clearly elucidated. In the present study, Al and Si species were separately added into MgO/Fe(II) and CaO/Fe(II) reactions containing SeO, studied by toxicity characteristic leaching procedure (TCLP), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray absorption fine structure (XAFS), and PHREEQC simulation. Approximately 42 % of SeO was reduced to SeO for MgO/Fe(II) reaction in the presence of Al species, being consistent with the case without Al species.

Associations of Gangue Minerals in Coal Flotation Tailing and Their Transportation Behaviors in the Flotation Process.

The mass production of flotation tailings has become a serious risk to the environment. Re-concentration of tailings is one of the best ways to solve this problem, which requires a better understanding of flotation tailings. In the present work, flotation kinetics, timed-release flotation, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and solid-state nuclear magnetic resonance (SSNMR) were used to analyze the properties of flotation tailings with different particle sizes and densities, the occurrence and binding state of gangue minerals in tailing, and the transportation behaviors in the re-flotation process.

Application of Geopolymer in Stabilization/Solidification of Hazardous Pollutants: A Review.

Geopolymers, as a kind of inorganic polymer, possess excellent properties and have been broadly studied for the stabilization/solidification (S/S) of hazardous pollutants. Even though many reviews about geopolymers have been published, the summary of geopolymer-based S/S for various contaminants has not been well conducted. Therefore, the S/S of hazardous pollutants using geopolymers are comprehensively summarized in this review.

A Bibliometric Analysis of Research Progress and Trends on Fly Ash-Based Geopolymer.

The objective of this work is to present the research progress and applications of fly ash-based geopolymer, and summarize the future research hotpots. Since 1998, scholars have made important contributions to the study of fly ash-based geopolymer, and a large number of research studies have been published. Therefore, a bibliometric analysis for the determination of the research status, trend, and history of fly ash-based geopolymer was conducted in the present study.

The Carboxyl Functionalized UiO-66-(COOH) for Selective Adsorption of Sr.

Efficient and selective removal of Sr is an important process for the safe use of nuclear energy. Herein, we investigate and assess the Sr adsorption properties of a metal-organic framework UiO-66-(COOH) functionalized by non-bonded carboxylic groups. This MOF is an exciting class of free carboxylic functionalized MOFs that combine chemical stability with gas sorption, dye elimination, and conductivity.

Immobilization of strontium in geopolymers activated by different concentrations of sodium silicate solutions.

Sodium silicate is always used as an activator for the synthesis of geopolymer. However, the effect of sodium silicate concentration on the geopolymer used as adsorbent was still unclear. Therefore, the immobilization of Sr in geopolymers activated by different concentrations of sodium silicate was studied through kinetic and isotherm modeling and solid characterizations including XRD, FTIR, TG, SEM-EDS, and N adsorption-desorption isotherm.