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In the study, MgAl binary water talc (MgAl-CO3-LDHs) was firstly synthesized by a steady-state co-precipitation method and then characterized by XRD, SEM and ICP-OES methods. The effects of n(Mg2+)/n(Al3+) in mixed salt solutions, pH and roasting temperature on the properties of MgAl-CO3-LDHs were mainly explored. The optimal adsorption condition of VO3- on MgAl-CO3-LDHs was determined as synthesis temperature of 25 °C, n(Mg2+)/n(Al3+) ratio of 3:1, pH 8 ± 0.1 and roasting temperature of 517 °C. The adsorption characteristics of MgAl-CO3-LDHs on VO3- were better fitted with Langmuir's isothermal equation and quasi-secondary kinetic equation. The adsorption mechanism was close to the monolayer adsorption with a saturated adsorption capacity of 53.73 mg/g. [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]

Adsorption is a simple and efficient phosphorus removal method used to control the eutrophication of water bodies. A simple and gentle atmospheric pressure hydrothermal method by adjusting the dosage of ammonium chloride and sodium hydroxide was used to synthesize amorphous, monoclinic, and tetragonal zirconia nano-powders with high specific surface areas (383.91 m2/g, 330.01 m2/g, and 234.36 m2/g) and particle size of about 40 nm for phosphate adsorption. When pH = 6.3, the phosphate adsorption capacity of the amorphous monoclinic phase and the tetragonal phase respectively reached 102.58 mg P/g, 68.11 mg P/g, and 37.25 mg P/g and the adsorption process of the three crystal forms of zirconia powders conformed to the Langmuir adsorption model. In the first 2 min of rapid adsorption, amorphous zirconia completed 76.23% of the adsorption process and the monoclinic phase also completed more than 60%. The adsorption process of the three crystal forms of zirconia was completed within 240 min and conformed to the pseudo-second-order kinetic model. Their adsorption characteristics of the three crystal forms of zirconia decreased with the increase in pH. While the pH was above than the isoelectric point of the solution, the adsorption capacity was significantly reduced. The large specific surface area and high hydroxyl content of the zirconia nano-powder made a great contribution to the adsorption process. [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]