Sorption of uranium(VI) onto hydrous ferric oxide-modified zeolite: Assessment of the effect of pH, contact time, temperature, selected cations and anions on sorbent interactions

Nekhunguni, Pfano Mathews; Tavengwa, Nikita Tawanda; Tutu, Hlanganani

doi:10.1016/j.jenvman.2017.09.034

Cited by 62 publications

(20 citation statements)

References 45 publications

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“…Sorption kinetics can effectively reflect the diffusion and rate of sorption (Pu et al 2013). Figure 7 shows that uranium sorption onto mullite is relatively rapid within 10 h. Because sorption was equilibrated after 20 h, 48 h was identified as the connect time for uranium sorption onto mullite for the experimental reaction equilibrium (Nekhunguni et al 2017).…”

Section: Sorption Kinetics Of Uranium Onto Mullitementioning

confidence: 99%

Uranium sorption onto mullite: Characteristics of isotherms, kinetics and thermodynamics

Long

Shi

et al. 2019

J Earth Syst Sci

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The sorption of uranium onto mullite influenced by pH, initial adsorbate concentration, sorption dose and reaction duration was probed utilising batch techniques. X-ray powder diffraction was used to characterise mullite. Sorption isotherms, sorption kinetics and thermodynamic characteristics were also investigated. The Freundlich isotherm model could best depict experimental data, suggesting that the sorption mechanism of uranium onto mullite may be multi-layer adsorption. The E value obtained from the Dubinin-Radushkevich model implied that uranium sorption onto mullite is a chemical process. The pseudo-second-order model successfully depicted uranium sorption onto mullite, indicating that the sorption rate is mainly controlled by chemical sorption. The thermodynamic parameters computed showed that entropy and enthalpy under the trial conditions were positive and that values of DG H were negative. Thermodynamics illustrated that the sorption process was endothermic and spontaneous. The results achieved in this study are intended to further a deeper comprehension of uranium migration in silicate minerals.

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Section: Sorption Kinetics Of Uranium Onto Mullitementioning

confidence: 99%

Uranium sorption onto mullite: Characteristics of isotherms, kinetics and thermodynamics

Long

Shi

et al. 2019

J Earth Syst Sci

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“…Freundlich assumes that adsorption occurs on a heterogeneous surface [9,26]. The freundlich isotherm model can be expressed by Eq.…”

Section: Adsorption Kineticmentioning

confidence: 99%

“…Uranium once released into the natural environment, it will lead to long-time potential precipitate to the soils, surface water and groundwater [7]. The World Health Organization (WHO) has classified uranium as a human cancercausing agent and its concentration in water should not exceed 15 µg/L [8,9]. Uranium waste is a very dangerous waste, therefore it needs to be processed so that it is not polluted to humans and the environment.…”

Section: Introductionsmentioning

confidence: 99%

“…This property is responsible for great adsorbent power of bentonite, especially toward ions in solution [19]. Cationic or anionic contaminants accumulate on bentonite surfaces leading to their immobilisation through the process of ion excange, coordination, electrostatic attraction, ion-dipole interaction, H-bonding, van der Waals interactions or hydrophobic bonding [9,20]. However for practical application bentonite as adsorbent need improvement in sorption capacity.…”

Section: Introductionsmentioning

confidence: 99%

“…The clay pillaring process involves exchange of the interlayer cations with large inorganic polymeric oxy-hydroxy cationic species, which prop open the silicate layers [9]. Thus, the interlayer and specific area increase.…”

Section: Introductionsmentioning

confidence: 99%

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Adsorption of Uranium Simulation Waste Using Bentonite:titanium Dioxide

Basuki¹,

Hasnowo

Jamayanti³

2019

urania

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ADSORPTION OF URANIUM SIMULATION WASTE USING BENTONITE TANIUM DIOXIDE. Bentonite is a clay material of high surface area that have galleries within its structure. Bentonite that is modified with TiO2 will have high adsorption capability. In this study, natural bentonite and bentonite:TiO2 were characterized with FTIR, XRD and BET instruments to determine functional group, basal spacing, and specific surface area. This study also investigates the adsorption of bentonite:TiO2 in various environmental factors, such as pH (pH 1, 3, 5, and 8), contact time (10, 20, 30, 40, 50, 60, 70, 90, and 120 min), and initial uranium concentration (20, 40, 60, 80 ppm), and their influences on adsorption capacity, and determine the kinetics equation and adsorption isotherm. Based on FTIR analysis, a decrease in the band of O-H bond from water molecule was observed, which indicates the presence of TiO2 in bentonite interlayer structure. The XRD characterization of bentonite:TiO2 does not show diffraction peak in 001 plane. This is due to delamination of bentonite interlayer structure. Delamination is caused by the presence of TiO2 in large quantities, thus damaging the bentonite interlayer structure into irregular sheets. Bentonite as sheets will cause the basal spacing to increase and it is anticipated that XRD will find it difficult in detecting the 001 plane at a low 2 theta angle. The surface area of bentonite:TiO2 has increased by 12.04 m2/g. The maximum adsorption capacity of U(VI) took place at pH 5.0 for 70 minutes contact time and uranium concentration of 60 ppm. In this study, the adsorption kinetic and adsorption isotherm are pseudo second-order kinetic and Langmuir isotherm. The kinetic constant and maximum adsorption capacity of bentonite:TiO2 are 0.075 g/mg.min and 5.848 mg/g respectively.Keywords: Bentonite, TiO2, Adsorption, Uranium

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A Simple Naphthamido‐based Fluorescent Chemoprobe for the Detection of Uranyl Ions

Heo

Choi

Park

et al. 2018

Bulletin Korean Chem Soc

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One of the most important challenges facing the nuclear field is the management of waste generated in the production of nuclear power. Radioactivity occurs inherently in the environment from the past several decades of anthropogenic pursuit including uranium mining, extraction, milling, and nuclear materials production, which has led to the generation and concentration of radioactive materials. 1-3 Heavy metal ions, such as uranium, lead, mercury, and arsenic, are exceptionally toxic elements that can pose a serious risk to human health and the environment. 4-6 Among these, uranium is a significant contaminant of water and soil, which has the most harmful consequence of human health. It can enter into the human body from food, water, and air, and cause serious health problems such as kidney damage, brain injury, and interruption of child's behavior. 7,8 Generally, uranium can exist in four different oxidation states, +3, +4, +5, and +6, but the most relevant form is the linear trans-uranyl ion (UO 2 2+ ). 9,10 Identification and quantification of UO 2 2+ play a significant role in nuclear scientific studies, as this information provides insight into the origin and threat caused by these materials. Therefore, considerable interest has been given to human health and environmental science to improve sensitive methods of selectively detecting and quantifying UO 2 2+ levels in an aqueous solution. Recently, researchers have developed efficient methods for the study of selective and sensitive UO 2 2+ detection, such as atomic emission spectroscopy, 11 total reflection X-ray fluorescence spectrometry, 12 surfaceenhanced Raman spectroscopy, 13 and cathodic stripping voltammetry. 14 However, these techniques include expensive instruments, and sample preparation is tedious and time-consuming. Therefore, it is necessary to develop facile and appropriate techniques for recognizing UO 2 2+ ions in an aqueous environment. In addition, chemical probes for the detection of UO 2 2+ were reported little. Herein, we report the development of a fluorescent probe for the determination of UO 2 2+ ions in the aqueous solution. Among various methods, fluorescence analysis recognizes more attraction due to its extraordinary quantum yield, emission at long wavelengths, high selectivity, good biocompatibility, and stability.

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Sorption of uranium(VI) onto hydrous ferric oxide-modified zeolite: Assessment of the effect of pH, contact time, temperature, selected cations and anions on sorbent interactions

Cited by 62 publications

References 45 publications

Uranium sorption onto mullite: Characteristics of isotherms, kinetics and thermodynamics

Uranium sorption onto mullite: Characteristics of isotherms, kinetics and thermodynamics

Adsorption of Uranium Simulation Waste Using Bentonite:titanium Dioxide

A Simple Naphthamido‐based Fluorescent Chemoprobe for the Detection of Uranyl Ions

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