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Spinel-type lithium ion sieves exhibit many advantages. We report a gallium ion-doped precursor LiGa0.1Mn1.9O4 prepared by co-precipitation and hydrothermal method. The optimal synthetic parameters were determined by the orthogonal design experiments. The precursor was then transformed into the corresponding ion sieve HGa0.1Mn1.9O4 by pickling. The dissolution loss of Mn3+ for HGMO (4.65%) is less than that of the pristine ion sieve without Ga3+ doping (6.59%), which proves that the doped Ga3+ inhibits the dissolution loss effect. The equilibrium adsorption capacity Qe of HGMO is 25.30 mg∙g−1 and the adsorption curve of HGMO for Li+ fits well with the pseudo-second-order kinetic model, indicating that the adsorption process is chemical adsorption. The adsorption isotherm conforms to the Langmuir model, and the adsorption process is monolayer adsorption. By the analysis of the adsorption enthalpy change (∆H), Gibbs free energy (∆G) and entropy (∆S) change of HGMO at different temperatures, the adsorption process of HGMO for Li+ was confirmed as endothermic and spontaneous. [ABSTRACT FROM AUTHOR]

Abstract: Owing to broad applications of boron products in many industries, boron waste pollutes the groundwater and leads to a chain of environment and health problems. In this research, a new kind of chelating resins with pyrocatechol functional group was developed, which could be used in various conditions for boron removal from aqueous solutions. Their boron uptake capacities, adsorption kinetics, ion-exchange isotherms, and regeneration ability were studied in the experiments. The equilibrium time of the resins for boron adsorption process was 12h. According to Langmuir isotherm analysis, the maximum sorption capacity of resins was 4.54mg/g at 25°C. The loaded resins could be eluted by 10% AcOH and there was no decrease in boron removal capacity after three times of recycles. [Copyright &y& Elsevier]

Highlights: [•] Introduce importance and relevant problem of boron. [•] Update study on removal of boron dissolved in water. [•] Present solutions for boron pollution. [ABSTRACT FROM AUTHOR]

• A Fe 3 O 4 -doped magnetic lithium ion-sieve were prepared to extract lithium from brine. • The morphological properties of LMO/FO were investigated by XRD, SEM, TEM and XPS. • The adsorption behavior, selectivity and dissolution loss of LMO/FO were investigated. Spinel lithium manganese oxide ion-sieve is considered the most promising adsorbents to extract lithium from brine. Here, we report a Fe 3 O 4 -doped magnetic lithium ion-sieve prepared by a facile hydrothermal method. The Fe 3 O 4 -doped lithium manganese oxide (LMO/FO) was first synthesized as the magnetic ion-sieve precursor. The chemical and morphological properties of LMO/FO were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that Fe 3 O 4 was uniformly dispersed in the precursor. Doping Fe 3 O 4 into LMO led to the increase of the average valence for Mn in the precursor from +3.48 to +3.53, which helps improve its structural stability. The equilibrium adsorption capacity of acid-treated LMO/FO (i.e. HMO/FO) was 29.33 mg/g which was greater than that of the undoped (i.e. HMO). Moreover, the adsorption behavior of the both ion-sieves well fitted with pseudo-second-order kinetic model. In 0.05 mol/L HCl solution, the desorption equilibrium could be achieved after 30 min. The dissolution loss of manganese and iron were 6.22% and 4.14%, respectively. The saturation magnetization value (Ms) of LMO/FO is 2.5 emu/g and the solid-liquid separation can be achieved by a magnet. In addition, the magnetic ion-sieve demonstrated excellent adsorption selectivity to Li+ in a mixed solution containing Li+, Na+, K+, Mg2+ and Ca2+. [ABSTRACT FROM AUTHOR]

• The micropores of fusain are extremely developed, especially the pores with D = 0.33–0.38 nm. • Aromatic interlamellar pores are important components of the fusain micropore structure. • The Langmuir volume (V L) under dry conditions is much larger than that under wet conditions. • The micropore volume and surface area of fusain did not positively correlate with the V L. • The blocking effect of water molecules resulted in the decrease of methane adsorption. Fusain is widely distributed in coal seams and studying its porosity and adsorption capabilities helps clarify the physical properties of coal reservoirs and gas adsorption mechanisms. The microporous structure characteristics and gas adsorption mechanism of fusain in lignite were studied based on methane and CO 2 adsorption experiments, combined with nuclear magnetic resonance (13NMR) and high-resolution transmission electron microscopy (HRTEM) measurements. Numerous micropores were found in the sample, and the pore volume and specific surface area were relatively large, which is similar to the results of the micropore test for meta-anthracite. The adsorption capacity of fusain was higher under dry base conditions but significantly lower under air-dry base and equilibrium water conditions. The chemical structure analysis results indicate that the micropores of fusain are mainly the interlamellar pores of the aromatic layers and the pore channels formed by them. Under dry conditions, the water in the microporous structure was removed, which provides an effective space for gas adsorption, resulting in more micropores for CO 2 adsorption and a higher methane adsorption capacity. Under wet conditions, the water occupies the adsorption site of methane, which hinders the gas entering the microporous channel of the fusain, resulting in a low adsorption capacity. On comparing the pore structure characteristics of fusain and meta-anthracite, it was found that despite possessing similar chemical structure characteristics of high polycondensation and similar micropore structure, there were clear differences in pore size, and their adsorption properties for methane were different. [ABSTRACT FROM AUTHOR]