CHEMICAL ENGINEERING JOURNAL
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2023
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IF 15.1
Tong Zhang,Yuan Chen,Yurong Zhang,Bin Liu,Yuanyuan Liu,Jianwei Zhao
Cr(VI) and catechol are common pollutants in wastewaters of tannery industry. Cr(VI) reduction by catechol results in accumulation of Cr(V)-complex and toxic o -benzoquinone. Cr(VI) reduction can be enhanced by accelerating the electron transfer from catechol to Cr(VI) using Fe(III). This electron transfer allows the continuous production of reactive oxygen species (ROS) in advanced oxidation processes, which further degrades catechol. However, the effects of catechol on Fe(III)-based Cr(VI) reduction and ROS production are not clear. In this study, the electron transfer pathway between catechol, Fe(III) and Cr(VI) was investigated along with the catechol degradation by ROS. Results show that the process of Cr(VI) reduction follows well a pseudo-second-order kinetic model, and the activation energy decreases by 4189 J/mol after electrons are transferred by Fe(III). Aqueous chromium (50 mg/L) was completely precipitated as Cr(OH) 3 , Fe x Cr 1-x (OH) 3 or Fe(OH) 3 -Cr(OH) 3 at Fe(III) concentration of 10 mmol/L. Residual catechol and Fe(II) in wastewater activated percarbonate, thereby producing OH for over 480 min at pH 3.0 and generating OH and CO 3 − for over 5 min at pH 10.0. Catechol was degraded by these ROS to butenedioic, oxalic, and formic acids, which were then mineralized to H 2 O and CO 2 . Catechol (2 mmo/L) was fully removed from wastewater with TOC removal of 37%, and the degradation was not affected by SO 4 2− and Cl − . This study provides new insights into the removal of pollutants from wastewaters via electron transfer mediated by Fe(III), and may aid in controlling the toxic effects of Cr(VI) and catechol-like organics in natural and engineered aquatic systems.
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BOLETIN DE LA SOCIEDAD ESPANOLA DE CERAMICA Y VIDRIO
·
2023
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IF 3.4
Feng Jiang,Junling Yu,Guo Feng,Tao Wang,Xiaojun Zhang,Quan Zhang,Rongchi Zhang,Qian Wu,Qing Hu,Yun Yu,Jianmin Liu
Novel (Cr,V)-ZrSiO 4 jewel green pigments with near-infrared reflection performance were prepared at a low temperature of 900 °C. Effects of Cr/Si mole ratio on phase composition, microstructure, Vis–NIR reflection performance, optical properties and thermal stability were studied. The results show that with the increase of Cr/Si mole ratio from 0 to 0.4, the color of the pigment changes from blue to jewel green and then to dark green. When the Cr/Si mole ratio is 0.2, the (Cr,V)-ZrSiO 4 jewel green pigment shows the best comprehensive properties, which has rendering performance ( L * = 56.69, a * = −18.52, b * = −9.28), thermal stability, and near-infrared reflection performance. The properties especially excellent near-infrared reflection performance make it promising functional pigment in heat insulation. Resumen Se prepararon nuevos pigmentos verde joya (Cr,V)-ZrSiO4 con rendimiento por reflejo en el infrarrojo cercano a una temperatura baja de 900 ̊C. Se estudiaron los efectos de la relación molar Cr/Si sobre la composición de fase, la microestructura, el rendimiento de reflexión Vis-NIR, las propiedades ópticas y la estabilidad térmica. Los resultados muestran que con el aumento de la relación molar Cr/Si de 0 a 0,4, el color del pigmento cambia de azul a verde joya y luego a verde oscuro. Cuando la relación molar Cr/Si es 0.2, el pigmento verde joya (Cr,V)-ZrSiO4 muestra las mejores propiedades integrales, que tiene rendimiento de renderizado (L* = 56.69, a* = -18.52, b* = -9.28), estabilidad térmica y rendimiento de reflexión en el infrarrojo cercano. Las propiedades especialmente excelente rendimiento de reflexión en el infrarrojo cercano lo convierten en un pigmento funcional prometedor en el aislamiento térmico.
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TRIBOLOGY INTERNATIONAL
·
2023
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IF 6.2
Hongming Wei,Gangwen Feng,Xiaoya Li,Wenyi Zhan,Feiyang Li,Yanzhang Dai,Jianpeng Zou
Cu/graphite composites are widely used in various fields as friction materials . However, their tribological properties are limited by the inadequate wettability between Cu and graphite and the insufficient strength of the Cu matrix. To strengthen Cu/graphite composites and improve their interface bonding, this investigation employed Cr 2 AlC to modify Cu/graphite composites fabricated by spark plasma sintering (SPS). The microstructure, interface characteristics, and tribological properties of the composites were thoroughly examined. The results show that the composites exhibit favorable tribological properties, which improved with the increase in sintering temperature . Specifically, as the sintering temperature increases from 800 °C to 980 °C, the friction coefficient of the composites decreases from 0.170 to 0.138, while the wear rate decreases from 9.92 × 10 −7 mm 3 /N·m to 1.86 × 10 −7 mm 3 /N·m.
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Polymer-Plastics Technology and Materials
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2023
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IF 2.7
Qianyong Liang,Ying Pan,Jia Du,Dong Zhang,Yan Zhang,Zhishun Zhong,Hongting Zhao
Carbon sphere@layered double hydroxides filled cellulose nanofibers (ACS@LDHs/CNF) aerogel was successfully synthesized. The removal rate of Cr(VI) using ACS@LDHs/CNFs aerogel at a solid-liquid ratio of 1 g/L was 89.4%, which was higher compared to the removal rate of 65.2% using LDHs alone. The adsorption capacity of ACS@LDHs/CNFs for Cr(VI) was determined to be 44.9 mg/g. The adsorption kinetics followed the pseudo-second-order kinetic equation, and the isotherm data showed good agreement with the Langmuir model. The adsorption mechanism of Cr(VI) onto ACS@LDHs/CNFs aerogel was also investigated. Additionally, the ACS@LDHs/CNFs aerogel demonstrated consistent high adsorption efficiency over 4 consecutive cycles of adsorption-regeneration.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2023
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IF 5.2
Wei Zhang,Ping Xiong,Qiao Li,Jiansheng Li,Jinyou Shen,Pengyu Zhu,Xiuyun Sun,Jingyu Lu,Ya Hu
EDTA-complexed heavy metals (EDTA-CHMs), one of the typical contaminants in industrial effluents , present challenges for wastewater purification because of their stability and high solubility over a wide pH range. Selective adsorption of various EDTA-CHMs coexisting in industrial wastewater is crucial for the recovery of heavy metal resources. Hence, investigating the competitive behavior and selective adsorption mechanisms of coexisting EDTA-CHMs during the effluent removal process is worthwhile. In this study, we chose Ferrihydrite (Fh) as the adsorbent and focused on the competitive adsorption behavior of two common EDTA-CHMs (EDTA-Cu(Ⅱ) and EDTA-Cr(Ⅲ)) on the Fh surface, as well as their removal mechanisms. For binary systems (EDTA-Cu(Ⅱ) and EDTA-Cr(Ⅲ)), the maximum adsorption capacity of Fh for EDTA-Cu(Ⅱ) was 17.32 mg/g, but because of the coexisting EDTA-Cu(Ⅱ), adsorption of EDTA-Cr(Ⅲ) by Fh was severely inhibited. In a competition experiment with binary contaminants of different EDTA complexes, Fh consistently exhibited stronger adsorption performance on EDTA-Cu(Ⅱ) when the ratio and addition order of EDTA-Cu(Ⅱ) and EDTA-Cr(Ⅲ) in the coexisting system was changed, and the valence state of the EDTA-CHMs was the key factor. The adsorption mechanism indicated that Fh could directly adsorb EDTA-CHMs through electrostatic interaction and surface complexation. The recycling rate of EDTA-Cu(Ⅱ) was still approximately 70.63% after five cycles of treatment with Na 2 SO 4 solution. This study provides new insights into the adsorption behavior of coexisting EDTA-CHMs on adsorbents and the selective removal of related pollutants.
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Polymers
·
2023
·Vol. 15
·期 13
·2918
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IF 5
Cheng Tang,Tao Hu,Chengzhen Du,Ziqin Liao,Wenyan Cheng,Fen Wang,Xiaoli Hu,Kunpeng Song
A Fe-N conjugated organic polymer (SMP-Fr-Py) was prepared from ferrocene and pyrrole using a Scholl coupling reaction, which significantly improved the performance of Cr(VI) removal compared to the polymer (HCP-Fr-Py) prepared by adding the cross-linker formaldehyde dimethyl acetal (FDA). The results showed that at a pH of 2 and at 25 °C, the removal of Cr(VI) reached 90% for SMP-Fr-Py and only 58% for HCP-Fr-Py after 20 min of reaction. Subsequently, 99% and 78% were achieved after 120 min of reaction, respectively. The test results showed that the removal reaction followed a pseudo-second-order kinetic model. The removal efficiency decreased with increasing solution pH and initial Cr(VI) concentration, but increased with increasing SMP-Fr-Py dosage, reaching three cycles. The characterization of the reaction complexes and measurements of Cr species conversion revealed the near absence of Cr(VI) species in the solution. Approximately 38% of Cr(VI) was found to be adsorbed on the material surface, with another fraction present in solution (24%) and on the material surface (38%) in the form of Cr(III). The overall study showed that the direct connection of ferrocene and pyrrole in SMP-Fr-Py through C-C bonding increased the conjugated structure of the polymer backbone, which facilitated electron transfer and transport. Furthermore, the Fe-N elements worked synergistically with each other more easily, which improved the removal performance of Cr(VI) and provided a reference for the subsequent work.Keywords:organic polymers;Fe-N co-doping;Cr(VI) removal;conjugate structure
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PubMed
高影响因子
Separations
·
2023
·Vol. 10
·期 6
·358
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IF 2.6
Xiangfen Cui,Juan Wang,Qun Zhao,Chen Li,Jianhong Huang,Xuewei Hu,Jie Li,Mantao Li
Biochar adsorption has emerged as a favorable and environmentally friendly approach for removing metals such as chromium (Cr) from wastewater. However, the use of pristine biochar (PBC) is limited due to its finite adsorptive capacity, selectivity, and potential for secondary pollution. In this study, a novel bifunctionalized magnetic biochar (BMBC) was fabricated by incorporating cystamine as a ligand and glutaraldehyde as a crosslinker into alkali-treated magnetic biochar (MBC). This chemical modification introduced numerous amino groups and disulfide bonds onto the surfaces of BMBC. The biochar adsorbents’ surface morphologies, crystal structures, and texture properties were characterized using SEM, XRD, and N2adsorption-desorption techniques. The specific surface area was determined using the BET method. Furthermore, the surface functional groups and elemental compositions before and after adsorption were analyzed using FTIR and XPS, respectively. The results demonstrated higher Cr(VI) removal efficacy of BMBC (100%) than MBC (72.37%) and PBC (61.42%). Optimal conditions for Cr(VI) removal were observed at a solution pH of 2, a temperature of 50 °C, a reaction time of around 1440 min, and an initial adsorbate concentration of 300 mg/L. The sorption process followed a chemical mechanism and was controlled by monolayer adsorption, with a maximum adsorption capacity of 66.10 mg/g at 50 °C and a pH of 2, as indicated by the larger fitting values of the pseudo–second-order and Langmuir models. The positive ∆Hoand ∆Sovalues and negative ∆G0 values suggested a spontaneous and endothermic Cr(VI) adsorption process with high randomness at the solid/liquid interface. The removal of Cr(VI) was attributed to the reduction of Cr(VI) into Cr(III) facilitated by the introduced amino acids, sulfur, and Fe(II), electrostatic interaction between Cr(VI) in the solution and positive charges on the adsorbent surface, and complexation with functional groups. The presence of co-existing cations such as Cu(II), Cd(II), Mn(II), and K(I) had little effect on Cr(VI) removal efficiency. At the same time, the co-existence of anions of Cl−, NO3−, SO42−, and HPO42−resulted in a 7.58% decrease in the Cr(VI) removal rate. After five consecutive adsorption/desorption cycles, BMBC maintained a high Cr(VI) removal rate of 61.12%. Overall, this novel BMBC derived from rice straw shows great promise as a biosorbent for treating Cr(VI) in wastewater.Keywords:magnetic biochar;bifunctionalization;chemical modification;hexavalent chromium;adsorption
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Molecular Catalysis
·
2023
·
IF 4.6
Yi Liu,Shuangjiang Li,Xiaojian Yu,Ying Chen,Xiaoning Tang,Tianding Hu,Lan Shi,Manoj Pudukudy,Shaoyun Shan,Yunfei Zhi
For the simultaneous attainment of the utilization of renewable biomass resources and the mitigation of greenhouse effects, it is very promising to develop a green, recyclable, and highly efficient heterogeneous catalyst for the synthesis of cyclic carbonates by CO 2 cycloaddition reaction with epoxides. Herein, novel cellulose nanofibers (CNF) supported (Salen)Cr(Ⅲ) complex was effectively synthesized for the aforementioned reaction. The cellulose nanofibers (CNF) were firstly modified with (3-aminopropyl) triethoxysilane (APTES), and then its Schiff base with salicylaldehyde was synthesized, which further subjected to coordination treatment with chromium chloride to form a novel heterogeneous catalyst, labelled as CNF-(Salen)Cr(Ⅲ). The catalytic performance of the catalysts shown that CNF-(Salen)Cr(Ⅲ) and co-catalyst TBAB can synergistically catalyze the cycloaddition of CO 2 with epichlorohydrin (ECH) at mild reaction conditions, and the yield of chloropropene carbonate (CPC) reached up to 97.8% with high selectivity. The CNF-(Salen)Cr(Ⅲ) complex maintained high catalytic activity after six cycles of repeated runs and has acceptable catalytic effect on other series of epoxies. Based on density functional theory (DFT) calculations, a reaction mechanism including adsorption activation of epoxides, epoxides ring opening, CO 2 insertion, and the formation of cyclic carbonate, was proposed for the CNF-(Salen)Cr(Ⅲ) complex catalyzed cycloaddition of CO 2 with epoxides.
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FUEL PROCESSING TECHNOLOGY
·
2023
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IF 7.5
Jie Xu,Xiaowei Liu,Rui Li,Boxiong Shen,Zijian Zhou,Lidan Deng,Lei Liu,Xinbo Zhu
Converting CO 2 into renewable fuel via photocatalysis is of significance to solving the energy crisis and climate change. However, the limited electron transfer in single catalysts always limits the reduction reaction. In this work, a p-n heterojunction was constructed between Cr doped MgAl–LDH (abbreviated as LDH) and Co 3 O 4 for visible-light-driven fuel production. Since LDH and Co 3 O 4 both have the sufficient potentials to drive CO 2 photoreduction, the constructed type-II heterojunction is more favorable for electron utilization efficiency. The optimal Co 3 O 4 /LDH heterojunction exhibited the highest CO evolution rate of 7.42 μmol•g −1 •h −1 and a CO selectivity of 90.5% with TEOA as sacrificial agent . The further characterizations highlight that the addition of Co 3 O 4 greatly improves the light absorption and the heterojunction effectively promotes the reverse migration of electrons and holes. This work investigates and verifies the designed type-II heterojunction based on MgAl–LDH, which has the guidance for the design of heterojunction catalysts and promotes the practical application of MgAl–LDH in photocatalytic region.
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FUEL PROCESSING TECHNOLOGY
·
2019
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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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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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