INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2019
·
IF 3.375
Qian Chen,Yi Feng,Rongrong Tian,Jinghang Chen,Anqing Wang,Jianfeng Yao
Photosensitization is a promising way to make UiO-66 visible light responsive. In this work, zirconium (Zr) precursors and synthetic methods (solvent-assisted or nonsolvent-assisted) were found to significantly affect the electric charge and the defect sites of UiO-66. UiO-66 with enhanced adsorption and photosensitized photocatalytic ability was then obtained. When ZrOCl2·8H2O was applied as Zr-precursor in a nonsolvent method, defect rich UiO-66 (UiO–OCl–N) was achieved with higher Cr(VI) adsorbing ability and improved photosensitized photocatalytic ability. Moreover, with the coexistence of Rhodamine B in Cr(VI) solution, photocatalytic performance of UiO-66 can be further enhanced.
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CHEMICAL PHYSICS
·
2019
·
IF 1.822
Tong-Tong Zhang,Xiang-Dong Gao,Yong-Qing Wu,Jing-Nan Yang,Xiao-Min Li
Cr-doped BaSnO 3 (BaSn 1-x Cr x O 3 , BSCO-x, x = 0–0.15) thin films with nanoporous structure were deposited on fluorine-doped tin oxide substrates via a colloidal solution route. The BSCO-x films exhibited single cubic perovskite phase and nanoporous feature, with the typical specific surface area of 18.98 m 2 /g and pore size of 10.75 nm (BSCO-0.15). The lowest band gap of 2.68 eV and a high transparency (above 70% in 500–800 nm) were realized in BSCO-0.15 film. This work paves a way toward perovskites with tunable band gap and nanoporous structures for varied photo and photoelectric devices.
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CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Jichi Zhang,Hongsen Zhang,Qi Liu,Dalei Song,Rumin Li,Peili Liu,Jun Wang
Hollow metal-organic frameworks (MOFs) have attracted wide interest because of their unique core-shell structure. As a novel uranium adsorbent, diaminomaleonitrile (DAMN) functionalized double-shelled hollow (DSHM) metal-organic framework of chromium(III) terephthalate was prepared by a post-synthetic method of grafting amino group onto coordinatively unsaturated sites (CUS). TEM, XRD, nitrogen sorption and FT-IR spectrometry were used to characterize the obtained DAMN functionalized hollow MOF. The maximum capacity of uranium adsorption is 601 mg g −1 , which exceeds all known functionalized MIL-101 uranium adsorption materials. The optimal adsorption pH is 8 which is close to the pH of seawater. Furthermore, the high selectivity of uranium and high adsorption rate in simulated seawater provide a promising prospect to introduce DSHM-DAMN for the extraction of uranium from seawater. In this work, we first applied hollow MOF for uranium adsorption, which greatly improves the uranium adsorption performance of MOF materials; we also explored the practical application of hollow MOF materials.
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FUEL PROCESSING TECHNOLOGY
·
2019
·
IF 4.507
Siquan Xu,Donghui Pan,Feng Hu,Yuanfeng Wu,Huazheng Wang,Yuan Chen,Hui Yuan,Lijing Gao,Guomin Xiao
In the presented work, a series of Cr/β zeolites were prepared and used as bifunctional catalysts with Brønsted and Lewis acidity in the conversion of biomass-derived carbohydrates to 5‑hydroxymethylfurfural (HMF). The physicochemical properties of all catalysts were characterized by ICP-AES, N 2 physisorption , solid-state 27 Al NMR, XRD, SEM-EDX, UV–Vis, XPS , Raman, NH 3 -TPD and Py-FTIR techniques. It was found that the catalysts with appropriate total acidity, ratio of Lewis to Brønsted acid sites and acid density appear to be beneficial for HMF formation. Under mild reaction conditions, a superior 72% HMF yield with 83% selectivity was achieved from glucose in the H 2 O/THF biphasic system by using the 0.4-Cr/β zeolite catalyst. Moreover, the results of the stability evaluation showed that the catalytic activity of the 0.4-Cr/β zeolite was not significantly lost after four consecutive cycles, and the framework remained intact. Therefore, the catalytic approach proposed in this study is believed to provide potential prospects for the production of HMF from biomass material refining in the future.
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CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Hang Liu,Shengqiang Song,Andrie M. Garbers-Craig,Zhengliang Xue
Cr 2 O 3 is a well-known corrosion resistant oxide used in refractory applications. However, it can oxidize into toxic and water-soluble Cr(VI) compounds upon reaction with calcium aluminate cement phases in the presence of oxygen, which subsequently causes disposal problems after use. This study describes the extent to which chromium in the spinel Mg(Al,Cr) 2 O 4 phase can be oxidized to Cr(VI) when it reacts with the calcium aluminate cement phases C 12 A 7 , CA, CA 2 and free CaO at 1300 °C in air, using XRD, XPS and leaching tests (TRGS 613 standard) as analytical tools. On reaction with CaO, the Mg(Al,Cr III ) 2 O 4 spinel mainly transformed into hauyne (Ca 4 Al 6 Cr VI O 16 ) and Ca 5 Cr 3 O 12 which contains both Cr(IV) and Cr(VI). The reaction of C 12 A 7 and CA with the spinel phase also resulted in the formation of Ca 4 Al 6 CrO 16 . Conversely, the reaction of Mg(Al,Cr III ) 2 O 4 spinel with CA 2 resulted in the formation of only a trace amount of Cr(VI). Water-soluble Cr(VI) leached in large quantities (>100 mg/L) from samples where the Mg(Al,Cr III ) 2 O 4 reacted with either C 12 A 7 or CA. Almost no Cr(VI) leached from the sample when Mg(Al,Cr III ) 2 O 4 reacted with CaO, using the standard TRGS 613 leach test, but a significant amount of Cr(VI) was released into solution when leached with a HCl solution for 12 h. Both Cr(IV) and Cr(VI) present in the Ca 5 Cr 3 O 12 dissolved into acidic solution. Only a small amount of Cr(VI) leached from the sample that resulted when spinel was reacted with CA 2 , even after a prolonged HCl leach. Cr(III) in spinel Mg(Al,Cr) 2 O 4 is very stable and does not leach in either distilled water or acidic solution.
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Nanomaterials
·
2018
·Vol. 8
·期 4
·263
·
IF 3.504
Jin Liu,Huihui Gan,Hongzhang Wu,Xinlei Zhang,Jun Zhang,Lili Li,Zhenling Wang
Porous hollow Ga2O3nanoparticles were successfully synthesized by a hydrolysis method followed by calcination. The prepared samples were characterized by field emission scanning electron microscope, transmission electron microscope, thermogravimetry and differential scanning calorimetry, UV-vis diffuse reflectance spectra and Raman spectrum. The porous structure of Ga2O3nanoparticles can enhance the light harvesting efficiency, and provide lots of channels for the diffusion of Cr(VI) and Cr(III). Photocatalytic reduction of Cr(VI), with different initial pH and degradation of several organic substrates by porous hollow Ga2O3nanoparticles in single system and binary system, were investigated in detail. The reduction rate of Cr(VI) in the binary pollutant system is markedly faster than that in the single Cr(VI) system, because Cr(VI) mainly acts as photogenerated electron acceptor. In addition, the type and concentration of organic substrates have an important role in the photocatalytic reduction of Cr(VI).Keywords:Ga2O3;porous;Cr(VI);organic pollutants
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高影响因子
Catalysts
·
2018
·Vol. 8
·期 9
·394
·
IF 3.465
Tian Zhao,Ming Dong,Ling Yang,Yuejun Liu
Nowadays, the controllable synthesis of stable hierarchical metal–organic frameworks (MOFs) is very important for practical applications, especially in catalysis. Herein, a well-known chromium–benzenedicarboxylate metal–organic framework, MIL-101(Cr), with a stable hierarchical structure, was produced by using phenylphosphonic acid (PPOA) as a modulator via the hydrothermal method. The presence of phenylphosphonic acid could create structural defects and generate larger mesopores. The synthesized hierarchical MIL-101(Cr) possesses relatively good porosity, and the larger mesopores had widths of 4–10 nm. The hierarchical MIL-101(Cr) showed significant improvement for catalytic activity in the oxidation of indene. Further, the presence of a hierarchical structure could largely enhance large dye molecule uptake properties by impregnating.Keywords:MIL-101(Cr);phenylphosphonic acid;hierarchical;enhanced catalytic activity;large molecule uptake
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RSC Advances
·
2018
·Vol. 8
·期 49
·27623-27630
·
IF 2.936
Xiaoli Huang,Qi Hu,Lei Gao,Qirui Hao,Peng Wang,Dongli Qin
A metal–organic framework, MIL-101(Cr), was used to adsorb sulfamethoxazole (SMZ) in water and activated persulfate (PS) oxidation was investigated to regenerate SMZ-saturated MIL-101(Cr). Adsorption and oxidation were combined in this study. MIL-101(Cr) was characterized by SEM, BET, XPS and FT-IR analyses. Effects of various operating parameters on adsorption efficiency were studied. The dosages of persulfate for SMZ desorption and oxidation were investigated. The results showed that the recommended pH was 6–8 for SMZ adsorption and optimum MIL-101(Cr) dosage was 0.1 g L−1. SMZ adsorption by MIL-101(Cr) was a spontaneous process and nearly exothermic. Saturation adsorption capacity was achieved in 180 s and the adsorption followed the pseudo-second-order model. The maximum adsorption amount of MIL-101(Cr) to SMZ was 181.82 mg g−1 (Langmuir). MIL-101(Cr) also showed good adsorption capacities for sulfachloropyridazine (SCP), sulfamonomethoxine (SMM), and sulfadimethoxine (SDM). Persulfate was helpful for SMZ desorption from the surface of saturated MIL-101(Cr) and sufficient persulfate could simultaneously oxidize the SMZ. XPS analysis showed that the structure of MIL-101(Cr) was stable after the persulfate oxidation process. Regenerated MIL-101(Cr) had the same level of adsorption capacity as fresh MIL-101(Cr). An adsorption–oxidation combined process may be set up based on the results. This study provides basic data for the deep treatment of organic micropollutants in urban water bodies.
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ELECTROCHIMICA ACTA
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2013
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IF 3.777
Ruizhuo Ouyang,Wangyao Zhang,Shilin Zhou,Zi-Ling Xue,Lina Xu,Yingying Gu,Yuqing Miao
We report here the successful fabrication of an improved Bi film wrapped single walled carbon nanotubes modified glassy carbon electrode (Bi/SWNTs/GCE) as a highly sensitive platform for ultratrace Cr(VI) detection through catalytic adsorptive cathodic stripping voltammetry (AdCSV). The introduction of negatively charged SWNTs extraordinarily decreased the size of Bi particles to nanoscale due to electrostatic interaction which made Bi(III) cations easily attracted onto the surface of SWNTs in good order, leading to higher quality of Bi film deposition. The obtained Bi/SWNTs composite was well characterized with electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), the static water contact angle and the voltammetric measurements. The results demonstrate the improvements in the quality of Bi film deposited on the surface of SWNTs such as faster speed of electron transfer, more uniform and smoother morphology, better hydrophilicity and higher stripping signal. Using diethylene triaminepentaacetic acid (DTPA) as complexing ligand, the fabricated electrode displays a well-defined and highly sensitive peak for the reduction of Cr(III)–DTPA complex at −1.06 V (vs. Ag/AgCl) with a linear concentration range of 0–25 nM and a fairly low detection limit of 0.036 nM. No interference was found in the presence of coexisting ions, and good recoveries were achieved for the analysis of a river sample. In comparison to previous approaches using Bi film modified GCE, the newly designed electrode exhibits better reproducibility and repeatability toward aqueous detection of trace Cr(VI) and appears to be very promising as the basis of a highly sensitive and selective voltammetric procedure for Cr(VI) detection at trace level in real samples.
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CHINESE JOURNAL OF CHEMISTRY
·
2014
·Vol. 32
·期 5
·434-442
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IF 1.04
Changhua Song,Hui Liu,Yuan Li,Shuai Ge,Hongwei Wang,Wenshuai Zhu,Yonghui Chang,Changri Han,Huaming Li
A series of metal-Al 2 O 3 catalysts were prepared simply by the conventional impregnation with Al 2 O 3 and metal chlorides, which were applied to the dehydration of fructose to 5-hydroxymethylfurfural (HMF). An agreeable HMF yield of 93.1% was achieved from fructose at mild conditions (100°C and 40 min) when employing Cr(III)-Al 2 O 3 as catalyst in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl). The Cr(III)-Al 2 O 3 catalyst was characterized via XRD, DRS and Raman spectra and the results clarified the interaction between the Cr(III) and the alumina support. Meanwhile, the reaction solvents ([Bmim]Cl) collected after 1 st reaction run and 5 th reaction run were analyzed by ICP-OES and LC-ITMS and the results confirmed that no Cr(III) ion was dropped off from the alumina support during the fructose dehydration. Notably, Cr(III)-Al 2 O 3 catalyst had an excellent catalytic performance for glucose and sucrose and the HMF yields were reached to 73.7% and 84.1% at 120°C for 60 min, respectively. Furthermore, the system of Cr(III)-Al 2 O 3 and [Bmim]Cl exhibited a constant stability and activity at 100°C for 40 min and a favorable HMF yield was maintained after ten recycles.
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Journal of the Taiwan Institute of Chemical Engineers
·
2017
·
IF 4.217
Ran Li,Qing-Da An,Bing-Qi Mao,Zuo-Yi Xiao,Shang-Ru Zhai,Zhan Shi
Employing mussel-inspired concept, a controllable “Sol-Gel-like” condensation of dopamine (DA) and aminosilane coupling agents (A1, A2, A3 represent APTMS, TSPED and TPDA, respectively) was undertaken to synthesize magnetic hollow composites (Fe 3 O 4 @A/PDA), aiming for removing Cr(VI) from wastewater. Compared to reported magnetic amino-functionalized composites for heavy metal removal, it is a new green process via post-grafting pathways that can avoid using organic solvents and high-temperature treatment. Structural characterization and batch experiments are correlated to illustrate the adsorption performance of resultant composites. Upon screening resultant adsorbents, Fe 3 O 4 @A2/PDA exhibited the highest adsorption capacity; the maximum Cr(VI) removal amount could be up to 284.1 mg g −1 at 298 K and pH 2.0. The pseudo-second-order and Langmuir model preferably fitted the adsorption process , besides, the activation energy is 7.17 kJ/mol −1 . The hollow composites could be easily separated from solutions by a magnet, and over 70% Cr(VI) could be removed even after five cycles. Electrostatic attraction and reduction reaction could be used to explain the adsorption mechanism that on the basis of XPS analysis. According to thermodynamic analysis, the adsorption is a spontaneous endothermic process. The high Cr(VI) adsorption capacity, fast adsorption kinetics and easy separation properties of hollow Fe 3 O 4 @A2/PDA composites make it be potential to alleviate Cr-containing aqueous solutions.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2016
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IF 3.782
Nannan Qin,Ya Zhang,Hongjian Zhou,Zhigang Geng,Gang Liu,Yunxia Zhang,Huijun Zhao,Guozhong Wang
The reactivity of zero valent iron (Fe 0 ) for removing Cr(VI) is self-inhibiting under neutral and alkaline conditions, due to the precipitation of ferrous hydroxide on the surface of Fe 0 . To overcome this difficulty, we incorporated a second metal (Co) into Fe 0 to form FeCo bimetallic nanoparticles (FeCo BNPs), which can achieve higher activity and significant improvement in the reaction kinetics for the removal of Cr(VI) compared with Fe 0 . The FeCo BNPs were synthesized by a hydrothermal reduction method without using any templates. The characterization analysis indicated that the products were highly uniform in large scale with 120–140 nm size in diameter. The obtained FeCo BNPs exhibited a remarkable removal ability for Cr(VI) in the pH range of 5.3–10.0. Especially, FeCo BNPs were able to reduce trace Cr(VI) (1.0 mg L −1 , pH = 7.5) down to about 0.025 mg L −1 within 1 h. XPS analysis confirmed that Cr(VI) was reduced to Cr(III) by FeCo BNPs, while Fe and Co was oxidized, implying a chemical reduction process. The enhanced removal of trace Cr(VI) could be originated from the introduction of Co, which not only served as a protecting agent against surface corrosion by galvanic cell effect, but also enhanced the efficient flow of electron transfer between iron and Cr(VI). All the results primarily imply that FeCo BNPs can be employed as high efficient material for wastewater treatment.
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