Carbon Letters
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2025
·
IF 5.8
Hu Chaoshuai,Liu Yuanxin,Zhang Jian,Zhu Yaming,Yin Xitao,Zhao Xuefei
Using durian shell as a carbon source and triethanolamine as a nitrogen dopant, nitrogen-doped carbon dots (N-CDs) were prepared via the hydrothermal method. First, by exploring different reaction times, reaction temperatures, and carbon source/dopant ratios to synthesize nitrogen-doped carbon dots, it is concluded that the best process conditions are 200 ℃, reaction time being 15h, and the dopant addition amount being 2mL. Structure and characteristics of the synthesized CDs were analyzed using X-ray photoelectron spectroscopy, Fourier-transform infrared, fluorescence (FL), ultraviolet–visible absorption, and Raman spectra. The N-CDs showed blue FL with a quantum efficiency of 4.28%. The FL characteristics of the N-CDs were utilized for ion detection, which demonstrated that \({\text{MnO}}_{4}^{ - }\) and \({\text{Cr}}_{{2}} {\text{O}}_{7}^{2 - }\) ions caused distinct FL quenching through static quenching, while other ions had no significant quenching effect. The detection limits for \({\text{MnO}}_{4}^{ - }\) and \({\text{Cr}}_{{2}} {\text{O}}_{7}^{2 - }\) were 37.5 and 46.2 nM, respectively. The N-CDs were subsequently employed to detect these ions in actual water samples, producing satisfactory results. Therefore, the preparation of N-CDs using durian shell as raw material and its application in practical detection work have good application feedback, which not only provides a new way for the reuse of fruit and vegetable wastes but also provides a new detection means for environmental monitoring pollutants.
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2025
·
IF 9
Yunxiao Ban,Jingang Wang,Cong Ma
In response to the contamination of water bodies by heavy metal pollution, particularly chromium (VI), this paper proposes a novel diverging microporous curved surface micro-vortex flocculation magnetic stable bed reactor for the treatment and purification of Cr(VI). The results show that under conditions of adding 0.0996 ∼ 1.373 mg/L FeSO 4 , 70 mg/L polyaluminum chloride (PAC), and 1.5 mg/L polyacrylamide (NPAM) respectively, and with an inlet flow rate of 0.023–2.101 m3/h for the reactor’s opposed-flow water distribution with different elevations, the removal rates of Cr(VI) and turbidity reach over 97 % and 99 %, respectively. By analyzing the instantaneous velocity vectors, streamlines, and vorticity distributions within the reactor using Particle Image Velocimetry (PIV) instruments, it is found that various turbulent flow patterns such as swirling flow, annular flow pattern, spiral flow, and water tongue flow are formed within the reactor. These flow patterns correspond to the generation of vortexes, micro-vortices, and micro-holes, resulting in a cascade flocculation phenomenon with their respective solid–liquid separation mechanisms. This makes the reactor a promising candidate for the treatment of heavy metal wastewater.
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Catalysis Science & Technology
·
2025
·
IF 4.2
Huan Tang,Jiaxin Liang,Yangzi Shangguan,Hong Chen
Reduction and stabilization of hexavalent chromium (Cr(VI)) in groundwater are essential for mitigating environmental and human health risks. In this work, we demonstrate the development of FeS2/Re-ANA composites (PM/RAs), a multifunctional material that integrates the chemical and photochemical reduction function within FeS2 with the ion-exchange capacity of the red soil-converted ANA type of zeolites for effective reduction and stabilization of Cr(VI) in groundwater. The PM/RA-3 composite material obtained an impressive Cr(VI) removal rate of 98.90% in a solution with 1 mg L−1 Cr(VI), reducing the residual concentration to 0.011 mg L−1, which complies with the WHO standards for drinking water quality. A detailed mechanistic investigation reveals that FeS2 facilitates both chemical and photoreduction of Cr(VI) to Cr(III), which is subsequently either adsorbed onto the FeS2 surface or immobilized through an ion-exchange process within the zeolite microporous channels. Furthermore, fixed-bed column studies using groundwater samples contaminated with Cr(VI) from a chromate production facility double confirmed the material's effectiveness in meeting discharge standards under environmentally relevant water conditions. This work highlights the potential of employing FeS2/Re-ANA composites as a promising material for treating Cr(VI)-polluted groundwater in permeable reactive barriers, offering a significant advancement for the control of the widespread Cr(VI)-contaminated groundwater pollution.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2025
·Vol. 37
·期 1
·45
·
IF 2.8
Luo Youmei,Gao Ziwei,Zhan Jiayin,Liu Shengda,Liu Guixia
Chromium (Cr), especially Cr(VI), is a notorious heavy metal pollutant with high toxicity, posing serious threats to ecosystems and human health. Recently, biomass-derived carbon dots (B-CDs) have emerged as promising materials in the field of sensing due to their low cost, environmental friendliness, and good optical properties. Developing a simple, sensitive, selective, and portable sensing platform based on B-CDs for the efficient detection of Cr(VI) in real environmental water samples is urgently required. Here, nitrogen-doped blue-fluorescent B-CDs were successfully synthesized via a one-step hydrothermal method utilizing loofah biomass as the carbon source and ethylenediamine as the nitrogen source. The as-prepared B-CDs possess abundant surface functional groups, excellent water solubility, remarkable fluorescence stability, and high selectivity toward Cr(VI). The B-CDs exhibit a wide linear detection range for Cr(VI) from 10 to 1000 μmol L −1 with a low detection limit of 194 nmol L −1 . The quenching mechanism was determined to be an internal filter effect. This method has been effectively applied to the accurate analysis of real water samples. Furthermore, portable paper-based and hydrogel-based sensors incorporating B-CDs have been developed, enabling convenient on-site detection of Cr(VI) in practical scenarios.
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ACS Applied Materials & Interfaces
·
2021
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IF 9.229
Li Yang,Hao Wu,Liang Zhang,Gaojie Zhang,Hongda Li,Wen Jin,Wenfeng Zhang,Haixin Chang
The intrinsically nonmagnetic feature of van der Waals (vdW) layered transition-metal dichalcogenide (TMDC) semiconductors limits the spintronic applications of these semiconductors. In this paper, we demonstrate a facile Te flux strategy to induce intrinsic ferromagnetism in the vdW layered 2H-MoTe2 semiconductor by magnetic chromium (Cr) doping. The Curie temperature (Tc) and saturation magnetization (Ms) can be well tuned by adjusting the Cr doping concentration. A notable Tc up to 275 K can be achieved for the vdW layered Cr-doped 2H-MoTe2 bulk crystals, which is much higher than that of recently reported van der Waals ferromagnetic semiconductors (Tc is mostly less than 70 K), in contrast to the diamagnetic feature of the pristine MoTe2. Meanwhile, the highest Ms of the vdW layered Cr-doped 2H-MoTe2 bulk crystals can reach 4.78 emu g–1, which is stronger than most values reported for magnetic-element-doped van der Waals materials. In addition, all of the as-grown semiconducting Cr-doped 2H-MoTe2 (Cr-2H-MoTe2) single crystals display a large magnetic anisotropy with an out-of-plane easy axis of magnetization. The observed ferromagnetism in the Cr-2H-MoTe2 has intrinsic characteristics, which can be mainly attributed to the spin polarization caused by Cr doping as confirmed by the density functional theory (DFT) calculations. Our approach offers an avenue to tune the ferromagnetism in the vdW layered semiconductor and explore its diverse spintronic and magnetoelectric applications.
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Food Science & Nutrition
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2022
·Vol. 10
·期 7
·2224-2235
·
IF 3.553
Zhentao Tang,Qingrong Han,Gang Yu,Fei Liu,Yuzhu Tan,Cheng Peng
Magnetic solid-phase extraction (MSPE) strategy based on the Fe 3 O 4 @PDA/MIL-101(Cr) has been proposed to separate and purify five common mycotoxins in licorice, including aflatoxin B 1 , aflatoxin G 1 , sterigmatocystin, zearalenone, and ochratoxin A. Integrating the MSPE and solid–liquid extraction/partitioning, a modified QuEChERS was established to adapt to the complex licorice samples. The Fe 3 O 4 @PDA/MIL-101(Cr) was successfully synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption–desorption isotherms. Sorbents with superior advantages for exclusion of matrix interference and extraction of target analytes in a short time were obtained, according to their ability of magnetic separation, high surface area (287.75 m 2 /g), large pore volume (0.61 cm 3 /g), and nanosized structure with mesopores. Prior to analysis with ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), several key parameters that would affect the sorbents’ extraction efficiency were extensively investigated. Under the optimized conditions, the practicality of the developed method for analysis of mycotoxins in licorice samples was confirmed by adequate linearity ( R 2 ≥ 0.9967), high sensitivity (LODs and LOQs, respectively, in the ranges 0.01–0.09 and 0.02–0.30 μg/kg), acceptable recovery (78.53%–116.28%), satisfactory reusability, and good interbatch precision of the sorbents (RSDs in the ranges 6.70%–11.20% and 6.02%–10.35%, respectively). The results indicated that the established method was feasible and reliable for the environment-friendly and rapid screening of mycotoxins in complex licorice samples.
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高影响因子
CHEMOSPHERE
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2022
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IF 8.943
Xiao Tan,Yinjie Zhang,Meng Liu,Jinman Cao,Guilan Duan,Jun Cui,Aijun Lin
Cr(VI) contamination in aquatic systems has been a challenge for environmental science researchers. To environmental-friendly, stable, and efficiently remove Cr (VI), a novel layered double hydroxide was prepared through the ultrasonic-assisted co-precipitation method. The ultrasonic-assisted step prevented the Fe 2+ oxidation, improved the morphology and performance, and finally, the adsorption-coupled reduction capacity and stability were enhanced. By adding U–Fe/Al-LDH (1.0 g/L) for Cr(VI) (100 mg/L), the removal rate reached 82.24%. The removal data were well fitted by the pseudo-second-order kinetic and Langmuir isotherm model. Using U–Fe/Al-LDH can be performed over a wide pH range (2–10), with a theoretical maximum removal capacity of 118.65 mg/g. The Cr(VI) with high toxicity was adsorbed and reduced to low-toxicity Cr(III). In the final phase, stable Cr(III) complex precipitates were generated. After 30 days, the dynamic leaching amounts of total Cr in used U–Fe/Al-LDH-2 were 0.1052 mg/L. Combined with the results of the influence experiment of coexisting anions and oxidants and the SO 4 2− release experiment, the stability of the removal effect and the safety of U–Fe/Al-LDH were proved. In conclusion, U–Fe/Al-LDH-2 is a promising remediation agent and a feasible Cr(VI) removal method for the practical remediation.
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JOURNAL OF HAZARDOUS MATERIALS
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2019
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IF 7.65
Yan Sang,Xi Cao,Guangdong Dai,Lvxuan Wang,Yin Peng,Baoyou Geng
The construction of heterojunction system can promote the separation and transfer of photogenerated electron-hole pairs, which is conducive to the degradation of sewage. In this paper, heterostructured Bi 2 O 3 /Bi 2 S 3 nanoflowers are fabricated by a one-step hydrothermal method. The microstructure and optical absorption properties are studied through the detailed characterization of this heterojunction. The visible light photocatalytic ability of as-prepared Bi 2 O 3 /Bi 2 S 3 heterojunctions are investigated by photocatalytic removals of RhB and Cr(VI). The results of photocatalysis indicate that removal efficiencies of RhB and Cr(VI) over Bi 2 O 3 /Bi 2 S 3 heterojunction are higher than those of pure Bi 2 O 3 and Bi 2 S 3 . The improved photocatalytic performance of the Bi 2 O 3 /Bi 2 S 3 heterojunctions could be attributed to a combination of the p-n junction between the p-type Bi 2 S 3 and n-type Bi 2 O 3 , and large specific surface areas (46.31 m 2 g −1 ). Moreover, the probable photocatalytic mechanism of composite photocatalysts is explored in detail by active species trapping experiments, N 2 adsorption–desorption, the transient photovoltage electrochemical impedance spectroscopy and photoluminescence measurements. This work provides new insights into building of the efficient and novel heterogeneous photocatalysts and other energy-related devices.
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JOURNAL OF POLYMER RESEARCH
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2016
·Vol. 23
·期 9
·1-9
·
IF 1.969
Kong Zhiyun,Wu Xiaoqing,Wei Junfu,Zhang Huan,Cui Li
The hydrophilic fibers based on 2-(dimethylamino)ethyl methacrylate (DMAEMA) which could remove Cr(VI) ions rapidly were prepared by UV-irradiation induced grafting of DMAEMA through pre-coating photoinitiator on the fibers and modifying with bromoethane(BE). The FTIR, FESEM, XPS, TG-DTG and contact angle spectra manifested that DMAEMA was grafted onto the surface of PP fibers and subsequently was quaternized. The maximum grafting degree (22.9 %) and exchange capacity of DMAEMA (1.2 mmol g −1 ) was obtained when PP fibers was immersed in BP concentration of 0.3 % for 4 h, irradiated with the DMAEMA concentration of 100 % and irradiation time of 20 min, and then was modified with BE. The modified fibers of PP-g-DMAEMA with bromoethane were proved to remove Cr(VI) and As(V) with removal rate of 97.3 % and 96.2 % within 10 min, respectively. The prepared fibers have potential application for the removal of Cr(VI) and As(V) from wastewater highly and rapidly.
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CHEMICAL ENGINEERING JOURNAL
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2018
·
IF 6.735
Juan Yang,Jingyi Hao,Siyu Xu,Jun Dai,Yan Wang,Xinchang Pang
In this study, Nb 2 O 5 nanorods/graphene composites (NbO NRs/GR) are prepared by one-pot alkaline hydrothermal process, utilizing the new roles of graphene oxide (GO) as the structure-directing and morphology-controlling agent for the growth of NbO NRs. Compared to blank NbO, NbO/GR composites exhibit significantly improved photocatalytic activity for 4-CP degradation under visible-light irradiation, although 4-CP and NbO do not absorb visible light themselves. The in-situ formation of surface complexes between 4-CP and NbO and the subsequent charge transfer based on LMCT mechanism can be responsible for the visible photocatalytic activity. And meanwhile, the photoelectrons transferred to GR surface from in-situ formed complex (NbO/4-CP) via NbO NRs can initiate the synergistic Cr(VI) reduction. The GR contents and NbO crystalline phase have great effects on the photocatalytic activity of NbO/GR composites toward simultaneous 4-CP degradation and Cr(VI) reduction. The amorphous NbO/GR composite with 4.0 wt% GR (NbO-400/GR-4.0%) shows the highest photocatalytic activity. The influences of various experimental conditions (including the surface fluorination of NbO/GR, the initial concentrations of 4-CP and Cr(VI), pH, reaction atmosphere, and adding radical scavengers) on the visible photocatalytic activities are investigated in detail. According to the catalytic activity, UV-vis DRS and FT-IR spectra of NbO/4-CP or NbO/GR/4-CP, and photocurrent response in aqueous 4-CP solution, the formation of the surface complex is evidenced and the visible-light catalytic mechanism based on LMCT process is proposed.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2018
·
IF 6.735
Fei Chen,Qi Yang,Yali Wang,Fubing Yao,Yinghao Ma,Xiaoding Huang,Xiaoming Li,Dongbo Wang,Guangming Zeng,Hanqing Yu
Despite massive research efforts are devoted into wastewater treatment, the coexistence of organic compounds and heavy metals is an escalating environmental problem, especially in surface waters. In this work, a rapid reduction of Cr(VI) and oxidation of refractory ciprofloxacin (CIP) were achieved simultaneously by the Ag/AgBr decorated BiVO 4 Z-scheme heterojunction under visible light irradiation. The ternary photocatalyst was fabricated by a facile hydrothermal method, followed by photoreduction process. Superior photocatalytic performance of Ag/AgBr/BiVO 4 was not only reflected in single Cr(VI) reduction or CIP oxidation, but also displayed in simultaneous removal of two contaminants, which should be attributed to the enhanced visible light absorption, high charge carriers separation efficiency and redox of their photo-generated electrons and holes in the constructed Z-scheme heterostructure. Characterization methods including UV–vis absorption spectra (UV–vis DRS), transient photocurrent response (PC), photoluminescence spectra (PL) and electrochemical impedance spectra (EIS) were employed to confirm the mechanism. The active species trapping experiments and electron spin resonance (ESR) measurements demonstrated that h + , O 2 − and OH all participated in CIP degradation, while e − and O 2 − were the main active groups for Cr(VI) reduction. The presence of Ag facilitated a Z-scheme Ag/AgBr/BiVO 4 photocatalyst due to its electron mediator role. The CIP mineralization was verified by three-dimensional excitation-emission matrix fluorescence spectra (3D EEMs) and total organic carbon (TOC) removal. At last, the possible CIP degradation pathway was also proposed. This work will provide a new route to design the novel Z-scheme photocatalysts for the simultaneous degradation of organic pollutants and reduction of heavy metal ions in water.
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APPLIED SURFACE SCIENCE
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2012
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IF 2.103
Zhen Wang,Xinbo Ci,Hongjun Dai,Lu Yin,Huixiang Shi
A highly photoactive Ti-containing Cr-modified MCM-48 photocatalyst (Si/Ti = 3.4, Si/Cr = 50) was prepared by a facile one-step method at room temperature. A combination of various physicochemical techniques such as X-ray diffraction (XRD), N 2 physisorption, diffuse reflectance UV–vis spectra (DRS) and X-ray photoelectron spectra (XPS) were used to characterize the properties of the synthetic catalysts. The characterization and experimental results indicated that tetrahedral Ti oxide moieties as dominant Ti oxide were loaded into the mesoporous structure and there was a synergistic interaction between the Ti species anchored on the walls and the Cr ions presented in the MCM-48 framework, which was considered to be directly correlated to the photoactivity. The Ti-Cr-MCM-48 sample can remove H 2 S with the efficiency of 92% under visible light, being the Cr 6+ species primarily responsible for this photoactivity. A deactivation was observed as a consequence of sulfate accumulation on the surface of the catalyst and reduction of Cr 6+ .
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