查找使用阿拉丁产品的科研文献

Recyclable UiO-66-NH2@Chitosan/Loofah fiber composite for efficient strontium capture

Xiangtao Tang,Lihong Lu,Fang Yang,Xingyu Zhong,Hongfa Shi,Wenqing Zhang,Lingfan Zhang

The treatment of radioactive wastewater containing 90 Sr required advanced adsorbents to address the limitations of the recyclable usage. In this study, a UiO-66-NH 2 @Chitosan/Loofah Fiber Composite (UNCL) was synthesized using an impregnation strategy, enabling easy separation from the solution and efficient Sr 2+ removal. By integrating the good adsorption activity of UiO-66-NH 2 , interfacial modification capability of chitosan, and macrostructural advantages of loofah fiber, the composite achieved enhanced mass transfer efficiency and structural stability. UNCL achieved adsorption equilibrium within 120 min, demonstrating rapid and efficient strontium capture capability. The material demonstrated robust performance under alkaline conditions, and retained high efficacy in real river water and seawater environments. Adsorption behavior aligned with the Sips isotherm model (R 2  = 0.999) and pseudo-second-order kinetics (R 2  = 0.995) with maximum adsorption capacity of 7.64 mg/g, confirming monolayer chemisorption. Mechanistic investigations, supported by FT-IR and XPS analyses, revealed a synergistic mechanism involving ion exchange, surface complexation and electrostatic interactions at multiple active sites. UNCL maintained approximately 90 % removal efficiency after five adsorption–desorption cycles and enabled facile separation from aqueous solutions through simple mechanical retrieval. These results demonstrated that UNCL combined adsorption ability, reusability, and environmental adaptability, positioning it as a promising and practical solution for Sr 2+ remediation.

Conversion of ethyl levulinate to γ-valerolactone catalyzed by Pd/UiO-66-NH2

Ying Gao,Jinxing Long

Conversion of ethyl levulinate to GVL was proposed using Pd 4 /UiO-66-NH 2 . • Pd 4 /UiO-66-NH 2 was constructed via a post-synthetic modification strategy. • Synergistic effects between Pd species and acidic sites drive superior performance. • GVL yield of 90% with 98.9% selectivity was achieved under 170 ℃ and 1.0 MPa H 2 . • The catalyst shows good recyclability, and can be reused for at least five runs. An efficient strategy is proposed for direct hydrogenation of ethyl levulinate (EL) to γ-valerolactone (GVL) using a highly dispersed palladium nanoparticles supported on the UiO-66-NH 2 framework (Pd/UiO-66-NH 2 ), which was prepared via a facile post-synthetic modification by anchoring palladium (Pd) nanoparticles on the framework's native -NH 2 groups. Under optimized conditions (170 °C, 1.0 MPa H 2 ), 90% yield and 98.9% selectivity of GVL were shown when the reaction was catalyzed by Pd 4 /UiO-66-NH 2 in cyclohexane. Catalyst characterization using XRD, N 2 adsorption-desorption, FT-IR, TEM, TGA, XPS and H 2 -TPR, confirmed that an intensive synergistic effect existed between the Pd and the acidic sites, which is responsible for the superior performance of Pd@UiO-66-NH 2 . The solvent effect and the feedstock adaptability were also investigated. Furthermore, the catalyst of Pd 4 /UiO-66-NH 2 demonstrated good stability and reusability, where no significant activity loss was shown even after five consecutive cycles. Therefore, this study provides new insights for efficient upgrading biochemical. Download: Download high-res image (188KB) Download: Download full-size image

Adsorption of phosphate on UiO-66-NH2 prepared by a green synthesis method

Xiaoting Zhang,Mingyu Liu,Runping Han

In this study, a zirconium-based metal organic framework (UiO-66-NH 2 ) was prepared with a green synthetic method for removal of phosphate from solution. Several characterization methods were performed and the adsorption property of UiO-66-NH 2 toward phosphate was explored in batch mode. There was a good adsorption performance for phosphate with a wide range of pH (pH = 2–11) with a slight effect of salinity . The adsorption capacity was up to 43.9 mg·g –1 at 303 K from experiments. The adsorption isotherms can be better described by Langmuir, Temkin, and Koble-Corrigan model while adsorption kinetics can be well fitted by Pseudo-second-order, Double Constant and Elovich model. The process was spontaneous and exothermic and the major mechanism of phosphate adsorption was complexation. The spent adsorbent can be well regenerated using 0.01 mol·L –1 NaOH. The study shows that UiO-66-NH 2 has the potential to remove phosphate from solution.

Biomimetic photocatalyst Ce/TCPP-UiO-66-NH2 for NADH regeneration and CO2 activation

Hao Guo,Likun Luan,Jinde Cai,Xiuling Ji,Haijun Yu,Yuhong Huang

CO 2 activation and conversion by enzymes to produce value-added multi-carbon compounds under mild conditions show significant impact on carbon neutrality. However, the enzyme co-factor NADH is expensive and the regeneration is still challenging for the enzyme reaction process. Inspired by natural photosynthesis, this study successfully developed a biomimetic photocatalyst Ce/TCPP-UiO-66-NH 2 (TCPP: meso-tetrakis (4-carboxyphenyl) porphine) for NADH regeneration and CO 2 activation. Structure analysis and spectra showed that the co-doping of Ce and TCPP reduced the band gap width of UiO-66-NH 2 , improved the separation efficiency of photo-generated carriers, and endowed it with excellent photocatalytic performance. The synthesized biomimetic photocatalyst Ce/TCPP-UiO-66-NH 2 was then applied for NADH regeneration. The regeneration efficiency of NADH can reach up to 95 % after 3 h of light reaction, which was about 1.6 times higher than that of the control group. Ultra-fast femtosecond time-resolved transient absorption (fs-TA) showed that Ce/TCPP-UiO-66-NH 2 possessed the shortest average decay time ( τ ¯ $\overline{\tau }$  = 1.12 ps), indicating shorter average life-time of carriers after Ce doping, thus suppressing hole-electron recombination. Finally, the key enzyme formate dehydrogenase (FDHPa) for CO 2 activation was immobilized on the membrane, combining with light regeneration of NADH for CO 2 production to formate. The formate yield (3.1 mM) was 16 times higher than that of the control group (0.19 mM). This work provided an effective strategy and efficient photocatalyst for the biomimetic photocatalytic activation of CO 2 to formate, which is an indispensable bridge for the further high-valuable C n compounds production by biocatalysis.

Effective toluene adsorption over defective UiO-66-NH2: An experimental and computational exploration

Xiaoyu Shi,Xiaodong Zhang,Fukun Bi,Zenghui Zheng,Lijun Sheng,Jingcheng Xu,Zhong Wang,Yiqiong Yang

In this thesis, defective UiO-66-NH 2 using cetyltrimethylammonium bromide (CTAB) as a template was successfully synthesized. The toluene adsorption-desorption properties were studied using breakthrough experiments and temperature programmed desorption (TPD). Modified UiO-66-NH 2 showed a high toluene increase due to the increased specific surface area and total pore volume and extra accessible adsorption sites generated by defects. Additionally, adsorption mechanisms were discussed at micro and molecule levels in light of density functional theory (DFT) calculations. By calculation, the amino hydrogen bonding gave rise to a higher toluene adsorption over UiO-66-NH 2 . In terms of the modified UiO-66-NH 2 with the most deficiencies, synergistic effects among π-π, -NH 2 , OH-CH 3 and OH-π hydrogen bonding strength also significantly intensified toluene adsorption. Furthermore, it could be noted that the OH-π interaction was stronger than the two bonded μ 3 -OH mechanisms. Notably, TPD and binding energies (BEs) depicted that defective UiO-66-NH 2 had a weaker toluene affinity than did UiO-66-NH 2 . Thus, gas toluene was easy to desorb with defective UiO-66-NH 2 at 298 K under atmospheric pressure. Finally, the repetitive regeneration experiment showed that the reproducibility of the materials was excellent.

Adsorption of Cr (VI) onto Attapulgite/UiO-66-NH2 Composites from Aqueous Solution

Peiyi Bao,Haiying Du,Xiangning Xu,Junya Li,Yao Wu,Shaojiang Zhou,Lingyun Li,Ningfei Lei

TiO2-UiO-66-NH2 nanocomposites as efficient photocatalysts for the oxidation of VOCs

Jinhui Zhang,Yun Hu,Junxian Qin,Zhenxiang Yang,Mingli Fu

TiO 2 -UiO-66-NH 2 nanocomposites with different mass ratios were successfully prepared by a simple solvent evaporation method for photocatalytic oxidation of toluene and acetaldehyde under UV light condition. The experimental results revealed that the nanocomposites exhibited superior removal efficiency for toluene and acetaldehyde than the pure TiO 2 , UiO-66-NH 2 and other TiO 2 -based porous materials during a 720 min of long-term evaluation under flowing conditions. The as-prepared 75TiO 2 -25UN nanocompoites exhibited the highest photocatalytic activity and CO 2 selectivity. The conversion of 75TiO 2 -25UN for toluene and acetaldehyde were 72.7% and 70.74% respectively, which was about 9.7 and 10.5 times higher than that of UiO-66-NH 2 , respectively. In addition, the CO 2 production of 75TiO 2 -25UN for toluene and acetaldehyde were 21.1 and 14.3 times higher than that of pure UiO-66-NH 2 , respectively. N 2 adsorption-desorption and SEM results revealed that high surface area could enhance the dispersion of TiO 2 and efficient contact to the VOCs. Photoelectrochemical properties indicated that photoinduced carriers can be efficiently separated and transferred via the interface of two components. The outstanding deactivation resistance was achieved over 75TiO 2 -25UN sample due to the efficient charge transfer and oxygen-rich condition. The possible mechanism of VOCs oxidation was proposed based on radical scavenger experiments, which proved that O 2 − and h + are the main active species. This work clearly demonstrated that MOF-based composite can be used as efficient photocatalysts for the application of VOCs oxidation.

Fabrication of cellulose nanofibrils/UiO-66-NH2 composite membrane for CO2/N2 separation

Xiong-Fei Zhang,Yi Feng,Zhongguo Wang,Mingmin Jia,Jianfeng Yao

Incorporating metal-organic frameworks into cellulose matrix to prepare composite membranes is promising in gas-separation applications. In this study, UiO-66-NH 2 (Zr-based MOF) nanoparticles are wrapped into the densely packed cellulose nanofibrils (CNF-COOH) via a facile vacuum filtration process. The existence of acid-base interactions and electrostatic forces between UiO-66-NH 2 and CNF-COOH renders ideal interfacial morphology. Results show that UiO-66-NH 2 is cross-linked by -COOH groups and well-dispersed in the CNF matrix. The porous UiO-66-NH 2 strengthens the diffusion process of CO 2 molecules, thus elevating the permeation flux and separation factor simultaneously. The optimum separation performance is achieved over CM-1 membrane with a CO 2 permeability of 139 Barrer and a CO 2 /N 2 selectivity ratio of 46.

Defective UiO-66-NH2 modified TCPP enhanced the photocatalytic reduction of Cr(VI)

Z.H.A.O.-X.U.A.N. Jiang

In this investigation, UiO-66-NH 2 was effectively synthesized through a solvothermal approach, utilizing benzoic acid and hydrochloric acid (HCl) as modulating agents. This synthesis process intentionally introduced defects mediated by benzoic acid, and the degree of these defects was precisely adjusted by the concentration of HCl. Subsequently, the material underwent a covalent modification process through an amidation reaction, resulting in the attachment of tetrakis (4-carboxyphenyl) porphyrin (TCPP). The results demonstrated a significant improvement in the photocatalytic reduction of Cr(VI), showcasing a 125 % elevation in reduction efficiency as compared to the unmodified UiO-66-NH 2 material serving as the baseline. The performance enhancement is due to the synergistic effect of the defect structure and TCPP modification, which enhances the light absorption, promotes charge transfer and separation, reduces the recombination rate, and improves the adsorption capacity and light absorption efficiency of Cr(VI). This research introduces an innovative approach and a highly effective catalyst, offering a novel solution for modifying metal-organic frameworks (MOFs) and enhancing their photocatalytic performance in the reduction of Cr(VI).

Efficient phosphate capture of Fe3O4/UiO-66-NH2/CeO2 in wide pH spectrum

Liyu Yang,Xiangcheng Shan,Yumeng Zhao,Zuoyi Xiao,Qingda An,Shangru Zhai

Eutrophication has long been one of the environmental pollution problems, and excess phosphate in water bodies is the main cause of this phenomenon. To solve this problem, magnetic adsorbent with Fe/Ce-loaded zirconium-based metal-organic framework (Fe 3 O 4 /UiO-66-NH 2 /CeO 2 ) was prepared by co-precipitation, microwave assisted and hydrothermal method . The results showed that different molar ratios of cerium and zirconium were the main influencing factors for phosphate adsorption, and the adsorbent exerted its maximum capturing capacity of 260.8 mg/g of phosphate when Ce:Zr = 4:1. The newly synthesized Fe 3 O 4 /UiO-66-NH 2 /CeO 2 was characterized by SEM, XRD , FT-IR, XPS, VSM and TGA . The adsorption process was found to be consistent with the Langmuir adsorption isotherm model and the pseudo-second-order model by batch experiments, indicating that the monolayer chemisorption dominated the adsorption process. Thermodynamic parameters obtained from temperature experiments proved that the phosphate adsorption process is a spontaneous endothermic absorption process and the adsorption experiments with coexisting ions (F − , Cl − , NO 3 − , SO 4 2− , HCO 3 − ) showed that the adsorbent has a unique selectivity for phosphate. Unlike most adsorbents previously studied, Fe 3 O 4 /UiO-66-NH 2 /CeO 2 exhibited consistently efficient adsorption performance over the pH spectrum tested (2 < pH < 10). After five cycles, the adsorbent still maintained favourable adsorption performance. Mechanism of Fe 3 O 4 /UiO-66-NH 2 /CeO 2 adsorption on phosphate was attributed to electrostatic attraction, ligand exchange and inner-sphere complexation. Therefore, the prepared Fe 3 O 4 /UiO-66-NH 2 /CeO 2 with wide pH suitability will be a promising option for capturing phosphate from wastewater.

Room-temperature hydrogen adsorption in Pd nanoparticle decorated UiO-66-NH2 via spillover

Jingchuan Wang,Junhong Luo,Yong Yao,Jiangfeng Song,Yan Shi

To improve room-temperature hydrogen storage, palladium (Pd) nanoparticles were innovatively decorated by carbon bridge onto the amino-group functioned Zr-terephthalate metal-organic framework (MOF) UiO-66 to reduce the diffusion energy barrier and then improve the hydrogen spillover effect. Powder X-ray diffraction shows broad Pd peak and retained UiO-66-NH 2 integrity after Pd decoration. The hydrogen uptake capacity show that UiO-66-NH 2 -Pd exhibits best hydrogen storage performance than UiO-66-NH 2 and pristine UiO-66. The hydrogen up taken in Pd decorated UiO-66 (UiO-66-NH 2 -1Pd) was close to 4 wt% under 20 MPa at room temperature. Density functional theory (DFT) calculations show that hydrogen adsorption energy of UiO-66-NH 2 -Pd was −0.5897 eV, which was much lower than that of UiO-66-NH 2 (−0.3716 eV) and UiO-66 (−0.2975 eV). Ultimately, Pd decorated NH 2 group functioned UiO-66 enable improve storage capacities through hydrogen spillover under ambient conditions which could satisfy the demand for sustainable energy, especially for the long-term storage energy media.

Preparation of KH560-UiO-66-NH2/Pebax mixed matrix membranes and CO2 separation

Wei Zhao,Hongjing Liu,Chengpeng Zhang,Yuyang Cao,Yuying Xu,Xueli Liu,Zhen Lu

Metal–organic frame UiO-66-NH 2 was modified by 3-glycidyl ether oxypropyl trimethoxysilane (KH560), and KH560-UiO-66-NH 2 was synthetized and added to Pebax to prepare KH560-UiO-66-NH 2 /Pebax mixed matrix membranes (MMMs). The epoxy group of KH560 had an amine-epoxidation reaction with the  NH 2 in UiO-66-NH 2 , which prevented UiO-66-NH 2 from agglutinating in the MMMs. In addition, the N  H bond and  OH bond of KH560-UiO-66-NH 2 could theoretically form hydrogen bonds with CO and N  H bonds in the main chain of polymerization, respectively, so as to improve the interfacial compatibility between fillers and polymers. The structure and properties of the filler particles and MMMs were evaluated by Fourier transform infrared spectrometer, x-ray diffraction, scanning electron microscopy, and thermogravimetric analyzer. The results showed that the filler particles were successfully synthesized, and had good crystallinity, uniform size distribution, and good thermal stability. The inorganic and organic interfaces of MMMs had no obvious interface defects. The obtained KH560-UiO-66-NH 2 /Pebax MMMs showed CO 2 permeability of 111.52 Barre and CO 2 /N 2 selectivity of 92.16, which were 85.65% and 88.73% higher than that of pristine membranes, respectively. The gas separation performance of MMMs was significantly improved, exceeding the upper bound of 2008 Robeson.