Hanlin Ding,Xiaonuo Zhang,Hao Yang,Xuegang Luo,Xiaoyan Lin
In this paper, a facile immobilization method was applied to load alginate , ferric oxide and dopamine onto fungal mycelium to prepare a series of spherical composites as potential adsorbents for the separation and removal of thorium from aqueous solution. The structure and chemical properties of the as-prepared adsorbents were characterized in detail via scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared spectrometry (FT-IR), X-ray photoelectron spectroscopy (XPS), pH value at the point of zero charge (pH PZC ) and thermogravimetric (TG) analysis. Based on the adsorption studies, the magnetic gamma-ferric oxide (γ-Fe 2 O 3 ) and polydopamine (PDA) cofunctionalized fungal microspheres (FPFMs) exhibited excellent adsorption performance for thorium and could represent convenient agents for the removal and recovery of thorium. The equilibrium adsorption data for the FPFMs were well fitted by the Langmuir model, and a high maximum thorium adsorption capacity of 326.346 mg·g −1 was obtained. The thermodynamic parameter values (Δ H 0 > 0, Δ S 0 > 0, Δ G 0 < 0) demonstrated that the thorium adsorption process was feasible, endothermic and spontaneous in nature. This work indicated that FPFMs have great potential to be employed as effective adsorbents for practical industrial water pollution treatment . Importantly, the possible mechanism of thorium adsorption on the homogeneous surface of FPFMs represented a combination of chelation interactions, coordination and ion exchange.
The capture and separation of uranium and thorium from acidic nuclear waste streams are imperative for safeguarding the environment and human well-being. Metal-organic frameworks (MOFs), an emerging class of porous materials, offer considerable potential for U(VI)/Th(IV) adsorption owing to their customizable pore size and processability. Nonetheless, the development of MOFs with robust adsorption capabilities for U(VI)/Th(IV) in acidic conditions poses a significant challenge. In this study, we introduce a feasible MOF design approach: the integration of high-valent metal centers with oxygen-rich organic ligands. Employing this strategy, we have successfully engineered a novel MOF adsorbent, SU-102(Hf), comprising hafnium-based metal clusters and ellagic acid as the organic linker. In a 0.3 M nitric acid environment, SU-102(Hf) demonstrates outstanding chemical stability and exhibits a high adsorption capacity for both uranium (27.38 mg g −1 ) and thorium ions (32.03 mg g −1 ), which represent a record of simultaneous adsorption capacity of uranium and thorium binary components by MOFs in a highly acidic environment (0.3 M HNO 3 ). Simultaneously, SU-102(Hf) also displays rapid adsorption kinetics, excellent selectivity, and recyclability for U(VI)/Th(IV) separation at pH = 3. Experimental investigations and theoretical calculations further unravel the adsorption mechanisms and key differences for Th(IV) and U(VI) ions.
Daqian Liu,Zuohai Liu,Min Huang,Taoyuan Xiu,Yun Wang,Zhirong Liu
A novel type of modified pyrolytic carbon (TOPO@PyC) was successfully prepared through incorporating tri-n-octyl phosphine oxide (TOPO). The adsorption behavior of TOPO@PyC for Th (IV) under strongly acidic conditions was investigated. The TOPO@PyC exhibited rapid Th(IV) adsorption rate with equilibrium time of 40 min. In 0.1–8 mol/l HNO 3 , the Th(IV) adsorption capacity reached between 43 and 50 mg/g. The adsorption kinetics and adsorption process of TOPO@PyC for Th(IV) can be well explained through the pseudo-second-order kinetic and Langmuir isothermal adsorption model. The temperature exhibited only a minor influence on Th(IV) adsorption capacity. The microstructure and adsorption mechanism of TOPO@PyC was characterized and elucidated through various techniques including SEM-EDS, BET, TGA, FT-IR, XPS and DFT calculations. By coordinating with O atom on TOPO, Th(IV) was successfully complexed on TOPO@PyC in a ratio of 1:3. Furthermore, TOPO@PyC manifested good thermal stability and acid resistance. After five times, the Th(IV) adsorption and desorption efficiency of TOPO@PyC still exceeded 95 %. Additionally, TOPO@PyC exhibited stronger selectivity towards Th(IV) from mixed solutions. Remarkably, it recovered over 90 % of thorium and uranium from the leachate of tantalum slag. Consequently, TOPO@PyC holds considerable promise in the treatment of strongly acidic wastewater containing thorium and uranium.
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