Publications by authors named "Zhiwu Lei"

In this research, a new synthesis approach was developed for an adsorbent, namely the phosphorylated ZIF-8/bamboo charcoal/chitosan/tannic acid (P-ZBCT) composite, for the efficient adsorption of uranyl ions from wastewater at low dosages. Impressively, the uranium adsorption rate of P-ZBCT reaches up to 98 % at a low dosage of 0.056 g/L in a 10-mg/L uranium solution, outperforming most reported uranium adsorption materials.

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In order to recover and effectively remove beryllium from beryllium-containing wastewater and relieve the environmental pressure caused by waste batteries. In this study, the gel material was synthesized based on the modified graphite material separated from the waste battery, and the graphite-@chitosan composite gel (CWBG@CH) was designed and synthesized. Interestingly, CWBG@CH has a maximum fitted adsorption capacity (Q) of 83.

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A novel environmentally-friendly porous hydrogel adsorbent (GHPN) is firstly designed and prepared using dextran, phosphate, and calcium hydroxide for the adsorption of Be(II). GHPN shows good adsorption selectivity for Be(II) (K = 1.53 × 10 mL/g).

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A novel polyvinyl alcohol-carbon nanotube containing an imidazolyl ionic liquid/chitosan composite hydrogel (termed CBCS) was prepared for highly selective uranium adsorption from seawater. The results show that CBCS has good adsorption properties for uranium within the pH range of 5.0-8.

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Land-based uranium resources are becoming scarce because of the widespread development and use of nuclear energy. Therefore, to make up for the shortage of uranium resources, a new chitosan/carboxymethyl-β-cyclodextrin/quaternary ammonium salt-functionalized amidoxime carbon adsorbent (CSAOCF) was designed and synthesized for extracting uranium from seawater. Experimental studies show that the adsorption of uranium by CSAOCF is a spontaneous endothermic reaction and chemical adsorption.

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In order to improve the removal rate of uranium and reduce the harm of radioactive pollution, a physically crosslinked polyvinyl alcohol/phosphorylated chitosan (PPP) hydrogel electrode was designed by freezing thawing method. The results show that PPP hydrogel has a good adsorption effect on uranium, and 200 mL of uranium tailings leachate is absorbed, and the treatment efficiency reaches 100 % within 15 min. PPP hydrogel can adapt to a wide range of pH conditions and exhibit excellent adsorption efficiency in the range of 3-9.

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Uranium mining, smelting, and nuclear industries generate a considerable amount of wastewater containing uranium. To treat this wastewater effectively and inexpensively, a novel hydrogel material (cUiO-66/CA) was developed by co-immobilizing UiO-66 with calcium alginate and hydrothermal carbon. Batch tests were conducted to determine the optimal adsorption conditions for uranium using cUiO-66/CA, and the adsorption behavior was spontaneous and endothermic, confirming the quasi-second-order dynamics model and the Langmuir model.

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The treatment of beryllium wastewater has become a major problem in industry. In this paper, CaCO is creatively proposed to treat beryllium-containing wastewater. Calcite was modified by an omnidirectional planetary ball mill by a mechanical-chemical method.

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A novel chitosan-based porous composite adsorbent with multifunctional groups, such as phosphoric acid, amidoxime, and quaternary ammonium groups, was prepared to improve the adsorption rate and competitive uranium‑vanadium adsorption of amidoxime group adsorbents. The maximum uranium adsorption capacity of PACNC was 962.226 mg g at 308 K and pH = 7.

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Aimed at the problem of excessive concentration of Fe and Mn in acidic mining wastewater during mining and utilization, a new rapid oxidative removal technology of Fe and Mn by a new-type biofilter system was designed and tested. The new-type biofilter system was constructed using a bioreactor filled with special mature bioceramic pellets after continuous biofilm cultivation as the filter layers. The results indicated that the biofilter system could efficiently treat five times its volume of wastewater per hour.

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Article Synopsis
  • - A new porous composite adsorbent called SPCCHC was created using chitosan and chlorella hydrothermal charcoal, which effectively adsorbs uranium (U(VI)).
  • - The adsorbent has a maximum capacity of 579.27 mg/g at 288 K and pH 6.5, showing that its adsorption process is spontaneous and exothermic.
  • - SPCCHC demonstrates strong selectivity for uranium over vanadium and can be recycled well, making it a promising candidate for extracting uranium from seawater.
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Article Synopsis
  • Researchers created Fe-activated carbon (Fe-AC) from lotus leaf using HNO activation, achieving a maximum adsorption capacity of 45.68 mg/g at specific conditions.
  • The adsorption performance of Fe-AC was found to be optimal under neutral pH, showing enhanced selectivity compared to alkaline and acidic conditions.
  • Characterization techniques indicated that the modification improved pore volume and surface area while reducing functional groups, which facilitated ion exchange for beryllium adsorption through a spontaneous and endothermic chemical process.
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The effects of surface heterogeneities on bubble-particle interactions have received little attention although heterogeneities are common for varieties of substance surfaces. In this work, heterogeneous surfaces consisting of discrete hydrophilic dots on a hydrophobic background were fabricated. The interactions between air bubbles and heterogeneous surfaces with different hydrophilic area fractions were investigated using a high-sensitivity microbalance coupled with a high-speed video camera.

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In order to remove and recover uranium from acidic uranium-bearing wastewater in uranium mining and metallurgy. Herein, a novel chitosan/Chlorella pyrenoidosa composite adsorbent bearing phosphate ligand (CSP/CP) was designed and synthesized, demonstrating a high uranium adsorption capacity at a pH of 5 and excellent selectivity in an aqueous solution with eight coexisting ions. The CSP/CP exhibits a maximum adsorption capacity (1393.

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Uranyl carbonate (UC(VI)) is a stable form of uranyl (U(VI)) that widely coexists with amorphous colloidal silica (ACSi) and humic acid (HA) in carbonate-rich U-contaminated areas. In this context, the cotransport behavior and mechanism of UC(VI) with ACSi (100 mg L) and HA colloids in saturated porous media were systematically investigated. It was found that the ACSi and strip-shaped HA have a strong adsorption capacity for UC(VI), and their adsorption distribution coefficient (K) is 4-5 orders of magnitude higher than that of quartz sand (QS).

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Uranyl carbonate (UC) and silica colloids (cSiO) are widely distributed in carbonate-rich subsurface environments associated with uranium pollution. Mobile colloids such as cSiO can affect uranium's transport efficiency in the groundwater environment. Therefore, elucidating the mechanism of UC and cSiO co-transport in a saturated porous medium with different ionic strength (IS), pH, and UC concentration is essential for the prevention and control of groundwater radioactive pollution.

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The goal of this study is aimed to develop a novel process to recycle the ferrous sulfate, the by-product of titanium dioxide industry. Zinc sulfate was added in the process of milling ferrous sulfate with calcium carbonate (CaCO). The sulfates were transformed into carbonates to serve as slow-release fertilizers by co-grinding the starting materials of FeSO·7HO, ZnSO·7HO, and CaCO with small amounts of water in a planetary ball mill.

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