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With sugarcane bagasse as the carrier and iron chloride hexahydrate (FeCl3·6H2O) as the iron source, Fe3O4@C materials were prepared in this study. Then the adsorption properties of the prepared adsorbents were characterized by XRD, SEM and VSM analysis. The effects of adsorption time, initial pH value and initial methylene blue concentration on methylene blue adsorption performance were studied and the adsorption mechanism was discussed. The Fe3O4@C materials synergistically exerted the good adsorption capacity and magnetic properties. The adsorption process of methylene blue on Fe3O4@C adsorbent was in accordance with Freundlich isothermal equation and quasi-second-order kinetic model. The saturated adsorption capacity in the experiment of Fe3O4@C material was 270.51 mg/g. The adsorption capacity was high in both acidic and alkaline environments, especially the alkaline environment. [ABSTRACT FROM AUTHOR]

With Miyi diatomite as the carrier and ferric nitrate as the modification agent, nano-micron vanadium adsorbent was prepared in the study. Then the adsorption properties of the prepared adsorbent were characterized by XRD, XRF, SEM, and ICP-OES analysis. The effects of adsorption time, initial pH value and initial vanadium concentration on VO3− adsorption performance were studied and the adsorption mechanism was discussed. The adsorption of VO3− on Miyi diatomite was significantly improved by the modification with ferric nitrate. The adsorption process of VO3− on nano-micron vanadium adsorbent was in accordance with Langmuir isothermal equation and quasi-second-order kinetic model. The saturated adsorption capacity was 43.38 mg/g. The adsorption capacity was higher in the weak acid environment and peaked at pH = 4. [ABSTRACT FROM AUTHOR]

The nanoakaganeite (β-FeOOH) was synthesized by the hydrothermal method in the study. The structural characterization and adsorption investigation of the produced materials were performed with powder X-ray diffractometer (XRD), scanning electron microscope (SEM), and inductively coupled plasma optical emission spectrometer (ICP-OES). Moreover, the influences of hydrothermal time, Fe3+ concentration, and hydrothermal temperature on the product structure and chromium adsorption were investigated. In addition, the influence of initial Cr(VI) concentration on chromium adsorption was investigated. The investigation results confirmed the optimal synthesis conditions of β-FeOOH as follows: 72 h hydrothermal reaction, 0.20 M Fe3+, and hydrothermal temperature at 70 °C. The as-synthesized β-FeOOH was spindle-shaped akaganeite. When the initial Cr(VI) concentration increased from 9.91 mg/L to 99.47 mg/L, the adsorption capacity increased and Cr(VI) removal rate decreased. Cr(VI) adsorption on β-FeOOH was a single-molecule layer chemical adsorption, conforming to the Langmuir adsorption model. The maximum saturation adsorption was 16.35 mg/g. [ABSTRACT FROM AUTHOR]

• This study proposes a high c (LiCl)-based hydrothermal cultivation method. • Crystal structure was regenerated and fragments of gibbsite were reassembled. • Adsorption capacity increased to 5.85 mg/g after repair. This study proposes a high c (LiCl)-based hydrothermal cultivation method for the structural damage regeneration of Li/Al-LDHs. The crystal structure was regenerated and small fragments of gibbsite were reassembled into rose petal-shaped Li/Al-LDHs. The analysis of Li+ adsorption kinetics and isotherm reveals that while the structural damage of Li/Al-LDHs has no impact on the mode or rate of adsorption, it does have a substantial effect on the adsorption capacity. This study provides a reuse method of Li/Al-LDHs. [ABSTRACT FROM AUTHOR]

Due to the lack of rare earth resources, the recovery of rare earth ions from industrial wastewater has been widely concerned. In this work, NaY molecular sieve was synthesized at 50–90 °C for 3–10 h without template and guide agent by low-temperature ultrasonic gelling method, and it was examined as the adsorbent to recover and enrich La3+ and Eu3+ in synthetic rare earth liquids. The properties of the synthesized NaY crystallization at 90 °C for 5 h were determined as follows: relative crystallinity of 99.49%, average particle size of 300 nm, specific surface area of 873.66 m2/g, and average aperture of 0.5617 nm. When the adsorption temperature was 25 °C, the pH was about 7, the initial concentrations of La3+ and Eu3+ were 227.00 mg/L and 195.30 mg/L, respectively, the amount of NaY was 0.01 g, and the volume of the rare earth simulant was 10 ml, the unit adsorption capacity and adsorption efficiency of La3+ were respectively 174.12 mg/g and 75.30%, and the unit adsorption capacity and adsorption efficiency of Eu3+ were 147.47 mg/g and 75.51%, respectively. After four cycles, the unit adsorption efficiency of La3+ and Eu3+ were still respectively 93.20 mg/g and 91.00 mg/g. The adsorption process showed a closer agreement with Langmuir isotherm and quasi-second-order kinetics model. The results indicate that this NaY molecular sieve is a promising adsorbent for rare earth recycling and enrichment from wastewater. [Display omitted] • NaY molecular sieve for rare earth adsorption is rapidly synthesized. • The synthesized NaY has good adsorption and desorption effect on La3+ and Eu3+. • NaY based on its ion exchange effect shows excellent cycle performance. [ABSTRACT FROM AUTHOR]

In order to solve the pollution of heavy metals and organic antibiotic in the water environment, a novel CuBi 2 O 4 /calcined ZnAlBi layered double hydroxides (CBO/CLDHs) composite was constructed and prepared via an ultrasonic-assisted calcination method for the adsorption and photocatalysis synergetic effect. Through varying the composition ratio, pH value, initial pollutant concentration and other pollutant interference, the simultaneous removal ability including adsorption and photocatalysis of as-prepared CBO/CLDHs composites for Cr(VI) and tetracycline pollutants was discussed. In particular, the CBO/CLDHs-1/15 composite showed that the removal efficiencies of Cr(VI) (40 mg/L) and tetracycline (40 mg/L) were both above 95%. Meanwhile, the XPS results confirmed that the toxic Cr(VI) was gradually reduced to non-toxic Cr(III) under visible light irradiation. The enhanced adsorption and photocatalytic activity was mainly attributed to the uniform distribution of calcined ZnAlBi layered double hydroxides nanosheets on the CuBi 2 O 4 microrods and the formation of heterojunctions. Moreover, cycle performance results revealed that the CBO/CLDHs-1/15 composite maintained high removal activity and stable structure after 4 photocatalytic cycles, and even showed a good adaptability while applied to the actual water in production and living environments. These results exhibited that the as-prepared CBO/CLDHs-1/15 composite has excellent adsorption and photocatalytic ability for the simultaneous removal of Cr(VI) and tetracycline, with a great potential application in practical waste water treatment field. [Display omitted] [ABSTRACT FROM AUTHOR]

A convenient and effective method was developed to fabricate zirconium-based calcium sulfate whiskers (Zr-CSWs), an environmentally friendly adsorption material designed to clean excessive fluoride from wastewater. Zr-CSWs, which potentially provide high adsorption activity toward fluoride in wastewater, overcome an aggregation problem typical of Zr-based species that may block the pore structure of the supporting material and degenerate its treatment performance. The results indicate that Zr-CSWs show excellent equilibrium adsorption capacity compared to other Zr-based materials in practical water solutions with pH values of 6–7. The adsorption of fluoride on Zr-CSWs was further evaluated in accordance with the Langmuir equation and the pseudosecond-order model. Coexisting anions had a minor effect on the removal of fluoride, and a strong alkali solution regenerated the used adsorbent. Density functional theory (DFT) calculations were performed to determine the mechanism of fluoride removal. The calculations demonstrated that the removal of fluoride by Zr-CSWs was mainly achieved by ion exchange between fluoride ions and OH- on the surface of the adsorbent, where a protonation process created low-coordination Zr atoms. [Display omitted] • Zirconium decorated calcium sulfate whisker (Zr-CSW) was prepared in a simple and low-cost way. • Zr-CSW has high capacity and good selectivity for the removal of fluoride in water. • The adsorption follows Langmuir model and pseudosecond-order dynamic equation. • The mechanism for fluoride removal has been revealed by density of functional theory (DFT). [ABSTRACT FROM AUTHOR]