查找使用阿拉丁产品的科研文献

In situ preparation of visible-light-driven carbon quantum dots/NaBiO3 hybrid materials for the photoreduction of Cr(VI)

Yixiao Wu,Chunlong Chen,Shu He,Xuesong Zhao,Shaobin Huang,Gongchang Zeng,Yingying You,Ying Cao,Lishan Niu

In this study, different carbon quantum dots (CQDs)/NaBiO 3 hybrid materials were synthesized as photocatalysts to effectively utilize visible light for the photocatalytic degradation of contaminants effectively. These hybrid materials exhibit an enhanced photocatalytic reduction of hexavalent chromium (Cr(VI)) in the aqueous medium. Zero-dimensional nanoparticles of CQDs were embedded within the two-dimensional NaBiO 3 nanosheets by the hydrothermal process. Compared with that of the pure NaBiO 3 nanosheets, the photocatalytic performance of the hybrid catalysts was significantly high and 6 wt.% CQDs/NaBiO 3 catalyst exhibited better photocatalytic performance. We performed the first-principles density functional theory calculations to study the interfacial properties of pure NaBiO 3 nanosheets and hybrid photocatalysts, and confirmed the CQDs played an important role in the CQDs/NaBiO 3 composites. The experimental results indicated that the enhanced reduction of Cr(VI) was probably due to the high loading of CQDs (electron acceptor) on NaBiO 3, which made NaBiO 3 nanomaterials to respond in visible light and significantly improved their electron-hole separation efficiency.

Removal of Cr(VI) and Ag(I) by grafted magnetic zeolite/chitosan for water purification: Synthesis and adsorption mechanism

Xiaoqi Liu,Yanyun Zhang,Yan Liu,Ting'an Zhang

In this paper, a novel grafted zeolite/Fe 3 O 4 /chitosan (ZMC-MAH-TEPA) adsorbent was greenly synthesized and evaluated for the removal of Cr(VI) and Ag(I) in single and bi-component solutions. The characterization data of XRF , XRD, FT-IR, VSM, TGA , BET and SEM showed the successful fabrication of the adsorbent with abundant -NH 2 and -NH- as well as great recovery properties (11.70 emu/g). The effects of experimental parameters, including pH value, initial concentration, temperature, time, and coexisting ions on single and bi-component adsorption, were investigated. The results demonstrated that the adsorption capacities increased with the enhanced shaking time and concentration until equilibrium was reached. The optimum pH value was 3 for Cr(VI) adsorption and 5 for Ag(I) adsorption. The maximum adsorption capacities for Cr(VI) and Ag(I) ions, obtained by the Langmuir model, were 50.75 and 70.12 mg·g −1 in single metal solutions and 45.45 and 58.94 mg·g −1 in bi-component metal solutions (Cr(VI)/Ag(I) = 1:1), respectively. Additionally, the adsorption mechanism of Cr(VI) and Ag(I) was explained in terms of electrostatic interaction and hydrogen bonding between metal ions and -NH 2 and -NH- in ZMC-MAH-TEPA. Taken together, this study provides a clean approach to synthesizing chitosan-based adsorbents for the efficient removal of Cr(VI) and Ag(I) ions.

Enhanced Cr(VI) removal in the synergy between the hydroxyl-functionalized ball-milled ZVI/Fe3O4 composite and Na2EDTA complexation

Chunfeng Wang,Yufan Wu,Tongxu Qu,Shasha Liu,Yunqing Pi,Jinyou Shen

The application of zero-valent iron (ZVI) for Cr(VI) removal often presents limitations due to its easy passivation. In this study, a column packed with hydroxyl-functionalized ball-milled ZVI/Fe 3 O 4 (HFB-ZVI/Fe 3 O 4 ) composite, assisted with Na 2 EDTA complexation, was developed to achieve sustainable treatment of Cr(VI)-containing wastewater. The results showed that at influent Cr(VI) concentration of as high as 50 mg/L, effluent Cr(VI) concentration below 0.5 mg/L was sustained for bed volume of as high as 1271 BV along with 2 g/L Na 2 EDTA concentration. Through the hydroxyl-functionalized treatment, FeOOH coating containing surface-adhering Fe(II) on the composite surface can be formed. Hydrolysis and auto-reduction of Fe(II)/Fe(III) species caused proton accumulation, resulting in remarkable attraction of anionic Cr(VI) via electrostatic interaction and exchange. Therefore, the reduction of Cr(VI) to Cr(III) was considerably enhanced. On the other hand, Na 2 EDTA complexation suppressed the growth of passivation layer and generated fresh corrosion products, thereby providing additional reactive sites for Cr(VI) removal. Additionally, Na 2 EDTA recovery and spent column regeneration were successfully proven. The remarkable effectiveness of Cr(VI) removal from actual electroplating wastewater confirmed the potential of the HFB-ZVI/Fe 3 O 4 composite-packed column and Na 2 EDTA assistance-coordinated system in full-scale application.

Rapid simultaneous adsorption and SERS detection of acid orange II using versatile gold nanoparticles decorated NH2-MIL-101(Cr)

Qinzhi Wang,Zhan Shi,Zhi Wang,Yijian Zhao,Jianuo Li,Huifan Hu,Yaowen Bai,Zhihao Xu,Hui Zhangsun,Li Wang

Acid orange II (AO II), a typical azo pigment, is strictly controlled by legislation and prohibited in foodstuffs. Herein, we prepared gold nanoparticles decorated amino-functionalized Cr-based metal-organic frameworks [NH 2 -MIL-101(Cr)@Au] via an in-situ reduction method as a surface-enhanced Raman scattering (SERS) substrate for simultaneous adsorption and detection of AO II. Gold nanoparticles are uniformly dispersed on the surface of NH 2 -MIL-101(Cr) owing to its three-dimensional (3D) structure and the interaction between –NH 2 and Au ions , providing more SERS-active “hot spots”. These NH 2 -MIL-101(Cr)@Au nanocomposites exhibited selective and high adsorption performance (419.85 mg g −1 ) for AO II, and could be used as superior SERS substrates for the detection of AO II with a low limit of detection (LOD) of 0.05 mg L −1 and wide detection range of 0.05–50 mg L −1 using portable Raman spectrometer. Furthermore, this SERS assay has been successfully used to determine AO II in orange juice and chili powder with good sensitivities.

Study on Adsorption and Desorption Performances of Trace C4–C6 Alkane Mixture on MIL-101(Cr) and WS-480

Tao Wang,Jing Gu,Qun Cui,Haiyan Wang

A deep purification treatment of trace volatile organic compounds (VOCs) in the tail gas emitted from the top of oil storage tanks was performed. Metal organic framework MIL-101(Cr) (hereinafter referred to as MIL-101) was used to remove trace C4–C6 alkane mixture in the tail gas. Compared with the commercial activated carbon, adsorption and desorption processes of trace C4–C6 alkane mixture as well as the adsorption thermodynamic property of n-hexane on MIL-101 were analyzed. Results demonstrate that the adsorption isosteric heat of n-hexane on MIL-101 is 48–52 kJ/mol, 9 kJ/mol lower than that on activated carbon. Trace C4–C6 alkanes on MIL-101 were desorbed by a nitrogen purge at 393 K, and the desorption efficiency of MIL-101 was up to 98.9%, which is 35% higher than that of activated carbon (∼64.3%). After 10 adsorption/desorption cycles, the desorption efficiency of MIL-101 exceeds 97%, indicating good cycle stability. The desorption process is affected by the spatial fit between the molecular configurations of alkanes and the three-dimensional tetrahedral cage of MIL-101 or by the one-dimensional slit pore of activated carbon. For alkanes with the same carbon, n-alkanes are preferentially desorbed on MIL-101, whereas isoalkanes are preferentially desorbed on activated carbon. Rich mesopores connected with the tetrahedral cages of MIL-101 are beneficial for desorption of trace C4–C6 alkanes. It provides basic data for the deep treatment of VOCs in the tail gas of oil storage tanks.

A cellulose-based adsorbent with pendant groups of quaternary ammonium and amino for enhanced capture of aqueous Cr(VI)

Xingtang Liang,Bin Liang,Jinyu Wei,Shuming Zhong,Ruirui Zhang,Yanzhen Yin,Yanjuan Zhang,Huayu Hu,Zuqiang Huang

As a promising candidate of Cr(VI) decontamination, cellulose is limited in the Cr(VI) uptake due to its poor accessibility. Herein, We describe the synthesis of a novel cellulose-based adsorbent (PQC, where P and QC designate the polyethylenimine and quaternized cellulose, respectively) with functional groups of quaternary ammonium and amino for enhanced capture of Cr(VI) from water. For preparing PQC, cellulose is first quaternized homogeneously, followed by grafting and/or cross-linking with polyethylenimine in the presence of epichlorohydrin. The PQC follows the Langmuir isotherm and presents a maximum Cr(VI) uptake capacity of 490.3 mg/g at 30 °C and initial pH about 2.0, much higher than many other reported cellulose-based adsorbents. The adsorption of PQC is spontaneous and endothermic, which follows the pseudo-second-order kinetic model and achieves the equilibrium after contacting about 50 min. Furthermore, the PQC, with favorable reusability, can work well in a high coexisting anion concentration. These excellent absorption performances are attributed to its physicochemical properties such as the robust porous structure and high density of functional groups including quaternary ammonium, amino and hydroxyl, which improve the availability to capture or reduce Cr(VI). This work demonstrates the significant potential of cellulose-based adsorbent for remediating aqueous Cr(VI).

Enhanced catalytic activity of NiM (M = Cr, Mo, W) nanoparticles for hydrogen evolution from ammonia borane and hydrazine borane

Kangkang Yang,Qilu Yao,Wei Huang,Xiangshu Chen,Zhang-Hui Lu

In this work, a series of Ni 1-x M x (M = Cr, Mo, W) nanoparticles (NPs) have been successfully synthesized via a simple surfactant-aided co-reduction method and employed as highly efficient and cost effective catalysts for hydrogen generation from aqueous solution of ammonia borane (NH 3 BH 3 , AB) at room temperature . It is found that the as-synthesized NiM NPs (M = Cr, Mo, W) exhibit much higher catalytic performance for the hydrolysis of AB as compared to that of pure Ni NPs. In addition, among all the Ni 1-x M x (M = Cr, Mo, W) NPs, the Ni 0.9 Cr 0.1 , Ni 0.9 Mo 0.1 , and Ni 0.8 W 0.2 NPs show the highest catalytic activities with the turnover frequency (TOF) values of 10.7, 27.3 and 25.0 mol H 2 (mol metal min) −1 , respectively. Remarkably, these optimized NiM catalysts can also perform efficiently in the hydrolysis of hydrazine borane (N 2 H 4 BH 3 , HB). The present low-cost and high-performance of the NiM catalysts system may encourage the practical application of AB and HB as the promising chemical hydrogen storage materials .

Fe/C materials prepared by one-step calcination of acidified municipal sludge and their excellent adsorption of Cr(VI)

Ruixue Shi,Tianbao Liu,Jing Lu,Xiangjing Liang,Andrei Ivanets,Junqin Yao,Xintai Su

Biochar derived from municipal sludge can be applied to adsorption. But it usually requires activation and pickling due to the generation of impurities such as metal oxide particles, which is uneconomical. Here, a facile strategy, acidification-one-step calcination, was developed and sludge-based Fe–C materials with good Cr(VI) removal effect were obtained by regulating the amount of hydrochloric acid . The results show that the adsorption capacity of Fe/C-5 (the best sample) for Cr(VI) was 150.84 mg g −1 . According to the Langmuir isotherm and pseudo-second-order kinetic model, the removal of Cr(VI) by Fe/C-5 is spontaneous and endothermic chemisorption process. In addition, Fe/C-5 has good ability to remove Cr(VI) under the interference of coexisting ions, and has good cycle stability. The removal of Cr(VI) by Fe/C-5 is considered to be synergistic process of adsorption and reduction. The Fe atoms were highly dispersed in Fe/C-5 and tightly bonded with C atoms, which not only strengthened the Cr(VI) adsorption by electrostatic attraction, but also activated the C atoms in the biochar material, so that the C atoms can reduce Cr(VI) to Cr(III) under acidic conditions. This may be due to the fact that acid pretreatment converted the iron in municipal sludge in the form of Fe–O/OH to free Fe 3+ and entered the C lattice during the calcination process. In this work, Fe–C materials with excellent Cr(VI) adsorption capacity were prepared by one-step calcination method, which has important reference significance for the resource utilization of municipal sludge.

A Novel Graphene Oxide Functionalized Hydrocalumite/Cellulose Composite for the Selective and Simultaneous Removal of Tetracycline and Cr(VI)

Soodamani Periyasamy,Jun Hou,Natrayasamy Visawanathan,Yang Li,Zijun Yang,Guoxiang You

Tetracycline antibiotic and hexavalent chromium removal from the wastewater is crucial for preventing future environmental trouble. This study aimed to develop an eco-friendly biocomposite made from an enhanced graphene oxide-functionalized hydrocalumite/cellulose composite for co-adsorbative removal of TC antibiotic and toxic Cr(VI). The synthesized GO@CellHC composite was characterized using various microscopic techniques. The GO@CellHC composite possessed the superior removal for TC and Cr(VI), achieving 27.4 and 42.6 mg/g in single systems, and 24.8 and 39.6 mg/g in binary systems, all within 40 minutes. In pH results, the maximum removal was observed at an acidic pH of 3 for Cr(VI) and 5 for TC, respectively. The co-ions results demonstrated that the composite efficiently removed both pollutants, except in the presence of PO 4 3- and CO 3 2- . The Langmuir isotherm indicated the strongest adsorption capacity and favored both systems. Thermodynamic studies revealed that the adsorption of both systems onto the GO@CellHC composite removes TC and Cr(VI) by endothermic and spontaneous system. Kinetic results demonstrated that TC adsorption shows a higher rate constant k 2 (single: 0.01676 min -1 and binary: 0.0138 min -1 ) compared to Cr(VI) adsorption (single: 0.01478 min -1 and binary: 0.01007 min -1 ). The GO@CellHC composite retained more than 80 % after three cycles, and field results suggesting that the biocomposite can be utilized for the removal of binary water pollutants.

Cr-leaching induced in-situ surface reconstruction of trimetallic CoFeCr-hydroxide on Ni foam for highly efficient water oxidation

Xiaorui Wang,Lingxing Zan,Hongling Zhang,Kun Tian,Dan Zhu,Jian Li,Qiang Weng,Cuicui Wang,Qingbo Wei,Wenlin Zhang,Xiangyang Hou,Feng Fu

s Rationally regulating the inevitable dynamic evolution of the catalyst surface structure towards high efficiency for water electrolysis remains a significant challenge. Here, the ternary cobalt-iron-chromium double hydroxide (DH) was synthesized on nickel foam as a monolithic catalytic electrode (CoFeCr-DH/NF) for the oxygen evolution reaction (OER) via a simple electrodeposition technique. The optimized Co 0.7 Fe 0.3 Cr-DH/NF electrode exhibited remarkable catalytic activity and stability. The overpotential at the current density of 100 mA cm −2 is only 281 mV, far exceeding those of other monolithic catalytic electrodes. Furthermore, we elucidated the variations in the valence states of metals during the OER process and found the electrochemical oxidation of Co 2+ to Co 3+ and leaching of Cr. Importantly, Cr-leaching can induce surface reconstruction, which not only optimizes the surface electronic structure to enhance the intrinsic activity but also increases the surface irregularity to enlarge the electrochemically active surface area, thereby significantly improving the OER performance. Theoretical calculations revealed that OER preferentially occurred at the adjacent Cr-leached Co sites and confirmed that the Cr-leached trimetallic CoFeCr-DH performs an outstanding OER performance.

Nano zero-valent iron supported by macroporous styrene ion exchange resin for enhanced Cr(VI) removal from aqueous solution

Wei Gao,Dengjie Zhong,Yunlan Xu,Han Luo,Sijing Zeng

Microwave-assisted synthesis of Zr-based metal-organic polyhedron: Serving as efficient visible-light photocatalyst for Cr(VI) reduction

Yu-Teng Zhang,Juan Zhu,Zhao-Yang Liu,Shuang-Bao Li,He Huang,Bao-Xu Jiang

For the first time, a microwave-assisted synthesis approach was used to prepare an amino-functionalized Zr-based metal–organic polyhedron (denoted as MW-ZrT-1-NH 2 ). The reaction time was shortened from 12 h to 2 min when compared to the traditional solvothermal method, resulting in crystalline products with good yield and purity. Herein, MW-ZrT-1-NH 2 was utilized as a photocatalyst for the catalytic reduction of Cr(VI) under visible-light irradiation. The results revealed that MW-ZrT-1-NH 2 exhibits better photocatalytic performance for Cr(VI) reduction. Furthermore, a plausible photocatalytic mechanism was proposed via electron spin resonance (ESR) measurements and radical trapping tests.