In-situ synthesis of Al2O3-TiO2 nanocomposite with enhanced adsorption performance to uranium(VI) from aqueous solution

Construction of montmorillonite-based materials for highly efficient uranium removal: adsorption behaviors and mechanism

In this work, Fe3+-doped and -NH2-grafted montmorillonite-based material was prepared and the adsorption ability for uranium(VI) was verified. The microstructure and pore size distribution of the montmorillonite-based material were investigated by N2 adsorption-desorption analyzer and scanning electron microscopy. The surface groups and composition were analyzed by Fourier transform infrared spectrometer, X-ray photoelectron spectrometer and X-ray diffractometer, which proved the successful doping of Fe3+ and grafting of -NH2. In the adsorption study, the adsorption reached equilibrium within 100 min with a maximum adsorption capacity of 661.2 mg/g at pH = 6 and a high adsorption efficiency of 99.4 % at low uranium(VI) concentration (pH = 6, m/V = 0.5 g/L). The mechanism study showed that the strong synergistic complexation of -OH and -NH2 for uranium(VI) played a decisive role in the adsorption process and the transport function of interlayer bound water could also enhance the adsorption probability of uranium(VI) species. These results were far superior to other reported similar materials, which proved that the Fe3+-doped and -NH2-grafted montmorillonite-based material possessed an extremely high application potential in adsorption, providing a new route for the modification of montmorillonite.

Low-Temperature Hydrotreatment of C4/C5 Fractions Using a Dual-Metal-Loaded Composite Oxide Catalyst

C4 and C5 fractions are significant by-products in the ethylene industry, with considerable research and economic potential when processed through hydrogenation technology to enhance their value. This study explored the development of hydrotreating catalysts using composite oxides as carriers, specifically enhancing low-temperature performance by incorporating electronic promoters and employing specialized surface modification techniques. This approach enabled the synthesis of non-noble metal hydrogenation catalysts supported on Al2O3-TiO2 composite oxides. The catalysts were characterized using various techniques, including X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, X-ray photoelectron spectroscopy, ammonia temperature-programmed desorption, infrared spectroscopy, and transmission electron microscopy. Mo-Ni/Al2O3-TiO2 catalysts were optimized for low-temperature hydrotreating of C4 and C5 fractions, demonstrating stable performance at inlet temperatures far below those typically required. This finding enables a shift from traditional gas-phase to gas-liquid two-phase reactions, eliminating the need for high-pressure steam in industrial settings. As a result, energy consumption is reduced, and operational stability is significantly improved.

Enhancing Uranium Removal with a Titanium-Incorporated Zirconium-Based Metal-Organic Framework

The urgent need to efficiently and rapidly decontaminate uranium contamination in aquatic environments underscores its significance for ecological preservation and environmental restoration. Herein, a series of titanium-doped zirconium-based metal-organic frameworks were meticulously synthesized through a stepwise process. The resultant hybrid bimetallic materials, denoted as NU-Zr-n%Ti, exhibited remarkable efficiency in eliminating uranium (U (VI)) from aqueous solution. Batch experiments were executed to comprehensively assess the adsorption capabilities of NU-Zr-n%Ti. Notably, the hybrid materials exhibited a substantial increase in adsorption capacity for U (VI) compared to the parent NU-1000 framework. Remarkably, the optimized NU-Zr-15%Ti displayed a noteworthy adsorption capacity (∼118 mg g-1) along with exceptionally rapid kinetics at pH 4.0, surpassing that of pristine NU-1000 by a factor of 10. This heightened selectivity for U (VI) persisted even when diverse ions exist. The dominant mechanisms driving this high adsorption capacity were identified as the robust electrostatic attraction between the negatively charged surface of NU-Zr-15%Ti and positively charged U (VI) species as well as surface complexation. Consequently, NU-Zr-15%Ti emerges as a promising contender for addressing uranium-laden wastewater treatment and disposal due to its favorable sequestration performance.

Recent advancement in nanomaterials for the detection and removal of uranium: A review

Uranyl ions U(VI), are the common by-product of nuclear power plants and anthropogenic activities like mining, excess utilization of fertilizers, oil industries, etc. Its intake into the body causes serious health concerns such as liver toxicity, brain damage, DNA damage and reproductive issues. Therefore, there is urgent need to develop the detection and remediation strategies. Nanomaterials (NMs), due to their unique physiochemical properties including very high specific area, tiny sizes, quantum effects, high chemical reactivity and selectivity have become emerging materials for the detection and remediation of these radioactive wastes. Therefore, the current study aims to provide a holistic view and investigation of these new emerging NMs that are effective for the detection and removal of Uranium including metal nanoparticles, carbon-based NMs, nanosized metal oxides, metal sulfides, metal-organic frameworks, cellulose NMs, metal carbides/nitrides, and carbon dots (CDs). Along with this, the production status, and its contamination data in food, water, and soil samples all across the world are also complied in this work.

Ultrasonic spray pyrolysis synthesis of TiO2/Al2O3 microspheres with enhanced removal efficiency towards toxic industrial dyes

Developing low-cost and highly effective adsorbent materials to decolorate wastewater is still challenging in the industry. In this study, TiO₂-modified Al₂O₃ microspheres with different TiO₂ contents were produced by spray pyrolysis, which is rapid and easy to scale up. Results reveal that the modification of γ-Al₂O₃ with TiO₂ reduced the crystallite size of Al₂O₃ and generated more active sites in the composite sample. The as-synthesized Al₂O₃-TiO₂ microspheres were applied to remove anionic methyl orange (MO) and cationic rhodamine B (RB) dyes in an aqueous solution using batch and continuous flow column sorption processes. Results show that the Al₂O₃ microspheres modified with 15 wt% of TiO₂ exhibited the maximum adsorbing capacity of ∼41.15 mg g^-1 and ∼32.28 mg g^-1 for MO and RB, respectively, exceeding the bare γ-Al₂O₃ and TiO₂. The impact of environmental complexities on the material's reactivity for the organic pollutants was further delineated by adjusting the pH and adding coexisting ions. At pH ∼5.5, the TiO₂/Al₂O₃ microspheres showed higher sorption selectivity towards MO. In the continuous flow column removal, the TiO₂/Al₂O₃ microspheres achieved sorption capacities of ∼31 mg g^-1 and ∼19 mg g^-1 until the breakthrough point for MO and RB, respectively. The findings reveal that TiO₂-modified Al₂O₃ microspheres were rapidly prepared by spray pyrolysis, and they effectively treated organic dyes in water in batch and continuous flow removal processes.

In situ synthesis of magnesium-doped hydroxyapatite aerogel for highly efficient U(VI) separation with ultra high adsorption capacity and excellent recyclability

Mg-doped HAP aerogel (MHAPA) was firstly in situ prepared via freeze-drying-calcination technology to capture U(VI). The U(VI) removal capacity by MHAPA even arrived 2685.6 mg g^-1, which was about 2 times over purchased HAP, illustrating that the incorporation of Mg ions could greatly enhance the U(VI) removal capacity. Compared with HAP, MHAPA also showed better anti-ion interference ability and dynamic removal performances. In comparison with other HAP-based adsorbents, MHAPA possessed good recyclability and its desorption rate was up to 93.4% in the first cycle. The excellent U(VI) removal performances of MHAPA might be owing to its low crystallinity and grain size, fast ion exchange rate and partial ionization under acidic conditions, which would accelerate the process of electrostatic attraction, ion-exchange, and complexation to immobilize U(VI). To sum up, the prepared MHAPA was expected to be an environmentally friendly, recyclable and effective adsorbent to immobilize U(VI) in actual wastewater.