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1.
Chemosphere ; 352: 141297, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38296211

ABSTRACT

The ubiquitous contamination of surfactants in wastewater has raised global concerns. Photocatalysis is deemed as a promising yet challenging approach for the decomposition of surfactant residues. Herein, a novel Z-scheme heterojunction of Bi4O5Br2/Bi2S3 with covalent S-O bonds was prepared via a facile one-pot hydrothermal and subsequent annealing process. The prepared optimal Bi4O5Br2/Bi2S3 composite exhibited remarkable photo-degradation activity towards the sodium dodecylbenzene sulfonate (SDBS). The Z-scheme reaction mechanism was proposed and validated by meticulous analysis of quenching tests, ESR spectroscopy and DFT calculations. Furthermore, the presence of chemical S-O linkages between Bi4O5Br2 and Bi2S3 was identified via FT-IR and XPS analyses, which served as a distinct bridge to modify the Z-scheme route for carrier transport. The Z-scheme heterostructure, in conjunction with chemical S-O bonds, synergistically enhanced the separation rate of electron-hole pairs and thus greatly boosted the photocatalytic activity. Additionally, the possible degradation pathways of SDBS were proposed by using HR-MS technology. Moreover, real hotel laundry wastewater could be efficiently disposed by the photocatalysis of the Bi4O5Br2/Bi2S3 with a decrease in the COD value from 428 to 74 mg/L, indicating that the fabricated Z-scheme heterojunction hold great promise for effectively removing refractory surfactant contaminants from aquatic environment.


Subject(s)
Benzenesulfonates , Pulmonary Surfactants , Wastewater , Spectroscopy, Fourier Transform Infrared , Surface-Active Agents
2.
RSC Adv ; 13(12): 8227-8237, 2023 Mar 08.
Article in English | MEDLINE | ID: mdl-36922941

ABSTRACT

Reducing the recombination rate of photoexcited electron-hole pairs is always a great challenging work for the photocatalytic technique. In response to this issue, herein, a novel Z-scheme CuInS2/In2O3 with interfacial S-O linkages was synthesized by a hydrothermal and subsequently annealing method. The Fourier transform infrared (FT-IR) and X-ray photoelectron spectrometer (XPS) measurements confirmed the formation of covalent S-O bonds between CuInS2 and In2O3. The quenching and electron spin resonance (ESR) tests revealed the Z-scheme transfer route of photogenerated carriers over the CuInS2/In2O3 heterojunctions, which was further verified theoretically via density functional theory (DFT) calculations. As expected, the CuInS2/In2O3 heterojunctions showed significantly boosted photocatalytic activities for lomefloxacin degradation and Cr(vi) reduction under visible light illumination compared with the bare materials. Accordingly, a synergistic photocatalytic mechanism of Z-scheme heterostructures and interfacial S-O bonding was proposed, in which the S-O linkage could act as a specific bridge to modify the Z-scheme manner for accelerating the interfacial charge transmission. Furthermore, the CuInS2/In2O3 heterojunction also exhibited excellent performance perceived in the stability and reusability tests. This work provides a new approach for designing and fabricating novel Z-scheme heterostructures with a high-efficiency charge transfer route.

3.
J Colloid Interface Sci ; 641: 916-928, 2023 Jul.
Article in English | MEDLINE | ID: mdl-36972626

ABSTRACT

The photo-Fenton process is promising for sincerely treating contaminated water. In this work, carbon-decorated iron oxychloride (C-FeOCl) is synthesized as a photo-Fenton catalyst for removing tetracycline (TC) from water. Three actual states of carbon are identified and their different roles in enhancing photo-Fenton performance are revealed. All carbon on/in FeOCl, including graphite carbon, carbon dots and lattice carbon, enhance visible light adsorption. More importantly, a homogeneous graphite carbon on the outer surface of FeOCl accelerates the transportation-separation of photo-excited electrons along the horizontal direction of FeOCl. Meanwhile, the interlayered carbon dots offer a FeOC bridge in helping the transportation-separation of photo-excited electrons along the vertical direction of FeOCl. In this way, C-FeOCl acquires isotropy in conduction electrons to ensure an efficient Fe(II)/Fe(III) cycle. These interlayered carbon dots extend the layer spacing (d) of FeOCl to about 1.10 nm, exposing the internal iron centers. The lattice carbon significantly increases the amounts of coordinatively unsaturated iron sites (CUISs) in activating hydrogen peroxide (H2O2) to hydroxyl radical (OH). Density functional theory (DFT) calculations confirm this activation on inner and external CUISs with a significantly low activation energy of about 0.33 eV.

4.
Small ; 19(18): e2207370, 2023 May.
Article in English | MEDLINE | ID: mdl-36765447

ABSTRACT

Water pollution caused by the massive use of medicines has caused significant environmental problems. This work first reports the synthesis and characterization of the Cu7 S4 /CuCo2 O4 (CS/CCO) yolk-shell microspheres via hydrothermal and annealing methods, and then investigates their photocatalytic performance in removing organic water pollutants. The 10-CS/CCO composite with yolk-shell microspheres exhibits the highest photodegradation rate of carbamazepine (CBZ), reaching 96.3% within 2 h. The 10-CS/CCO also demonstrates more than two times higher photodegradation rates than the pure (Cu7 S4 ) CS and (CuCo2 O4 ) CCO. This outstanding photocatalytic performance can be attributed to the unique yolk-shell structure and the Z-scheme charge transfer pathway, reducing multiple reflections of the acting light. These factors enhance the light absorption efficiency and efficiently transfer photoexcited charge carriers. In-depth, photocatalytic degradation pathways of CBZ are systematically evaluated via the identification of degradation intermediates with Fukui index calculation. The insights gained from this work can serve as a guideline for developing low-cost and efficient Z-scheme photocatalyst composites with the yolk-shell structure.

5.
J Colloid Interface Sci ; 629(Pt A): 355-367, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36084443

ABSTRACT

High-efficiency separation of photogenerated charges and molecular oxygen activation is very important for photocatalytic removal of organic pollutants. However, the current understanding of the effect mechanism of metal substitution for the separation of photo-generated charges and molecular oxygen activation is still poor. Herein, efficient manganese (Mn)-doped BiOBr hollow microspheres synthesis, systematic characterizations, and theoretical calculation discovered that Mn-doping could not only induce produce oxygen vacancies (OVs), but also can act as active sites for catalytic reactions. The induced production of OVs and Mn2+/Mn3+ by Mn optimal doping introduced into BiOBr can synergistic promote the separation of photogenerated charges and molecular oxygen activation leads to significantly enhances degradation of crystal violet (CV). Upon analysis, Mn-doping introducing unsaturated d-orbital with bridging O2- formation π-donation accelerated the separation of photo-generated charges. Meanwhile, the larger overlap of Mn-3d orbitals with O2-2p orbitals forms a π-donation bond with charge transfer from metal to O2 leading to the oxygen-oxygen (OO) bond length and molecular oxygen activation. Finally, we proposed a possible mechanism to explain the highly efficient photocatalytic degradation performance of the acquired photocatalysts. This study provides not only a novel strategy for the rational design of highly active photocatalysts, but also in-depth insights into the separation of photo-generated charges and molecular oxygen activation.


Subject(s)
Environmental Pollutants , Manganese , Manganese/chemistry , Microspheres , Gentian Violet , Oxygen/chemistry
6.
J Colloid Interface Sci ; 630(Pt B): 866-877, 2023 Jan 15.
Article in English | MEDLINE | ID: mdl-36356452

ABSTRACT

The photo-Fenton performance of Fe-based metal organic frameworks (Fe-MOFs) largely depends on the amount and the local electron density of metal coordinately unsaturated sites (M CUSs). However, a majority of Fe active sites are fully bound by organic ligands leading to decreased Fe CUSs. Additionally, the symmetrical electronic distribution of iron-oxo (Fe-O) clusters and the fast electron-hole recombination are unbeneficial for the directional electron transfer and the following electron accumulation on Fe CUSs. Herein, the structure of Fe-O clusters onto the framework of MIL-88B was controllably regulated via change of Ce doping amount, among which Fe0.8Ce0.2-MIL-88B exhibited highest removal efficiency of tetracycline (TC). That was mainly ascribed to the following two points: for one, the induced ligand missing defects ameliorated the pore structures and generated more M CUSs; for another, the lower electronegativity of Ce than Fe and the role of ligand missing defects as electron trap state collectively increased the local electron density at Fe CUSs. As a result, the increased M CUSs provided more active sites for H2O2 coordination and the highly concentrated electrons density at Fe CUSs afforded the substantial electron donation towards robust H2O2 dissociation into ∙OH. Furthermore, the increased mesoporous size favored highly-efficient utilization of ∙OH. This work provides a facile strategy to improve photo-Fenton performance of Fe-MOFs.


Subject(s)
Cerium , Metal-Organic Frameworks , Metal-Organic Frameworks/chemistry , Iron/chemistry , Electrons , Hydrogen Peroxide/chemistry , Lewis Acids , Ligands
7.
Chemosphere ; 308(Pt 1): 136156, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36029866

ABSTRACT

Difficult storage of hydrogen peroxide (H2O2), low production of reactive oxygen species (ROS), and inefficient Fe(II)/Fe(III) recycling limit the application of the Fenton-like process. Calcium peroxide (CaO2) based iron oxychloride (FeOCl) system was developed for solving these deficiencies, and ciprofloxacin (CIP) was effectively degraded within 20 min treatment. 0.33 mmol/L H2O2 and 2.4 mg/L dissolved oxygen (DO) were produced via CaO2. Quenching experiments and electron paramagnetic resonance results confirmed that hydroxyl radicals (·OH) and superoxide anion (·O2-) worked as the main ROS. Density functional theory (DFT) calculations and experimental results suggested that H atoms of H2O2 adsorbed on FeOCl favored the activation of H2O2 into ·OH and DO into ·O2-, and electrophilic Cl and O coordination in FeOCl contributed to the cycle of Fe(II)/Fe(III). ·OH and·O2- were responsible for CIP degradation, and toxicity assessments demonstrated that the developed system reduced the hazard of treated solution. Clarity of FeOCl/CaO2 system triple roles, including H2O2 and O2 production, activation into ROS, and Fe(II)/Fe(III) recycling, facilitates the efficient utilization of O2 in Fenton-like system.


Subject(s)
Hydrogen Peroxide , Superoxides , Ciprofloxacin , Ferric Compounds , Ferrous Compounds , Oxidation-Reduction , Oxygen , Reactive Oxygen Species
8.
Chemosphere ; 303(Pt 1): 134973, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35588882

ABSTRACT

Construction of Z-scheme heterostructure is an effective strategy to enhance the charge carriers' separation. However, successfully achieving this on the defect heterojunction to improve the photocatalytic activity remains challenging. This work successfully obtained sulfur vacancy in the ZnIn2S4/BiOBr (SZIS/BOB) heterojunction composites with S-O covalent bonding using a hydrothermal method. As a result, they exhibited superior photocatalytic and stability performance. The optimized SZIS/BOB-10 exhibited excellent rhodamine B degradation (95.2%) and chromium (VI) reduction (97.8%) within 100 min under visible light. The enhanced composites with S-vacancies, S-O bond, and internal electric field induced the Z-scheme charge transfer mechanism. We had verified this mechanism based on the surface photovoltage spectra, electron spin response spectra, and density functional theory calculations. This work not only provides valuable insights into designing photocatalysts with a direct Z scheme heterostructure but also delineates a promising strategy for developing efficient photocatalysts to degrade organic pollutants.


Subject(s)
Chromium , Water , Bismuth , Software
9.
Nanoscale Res Lett ; 13(1): 148, 2018 May 11.
Article in English | MEDLINE | ID: mdl-29752595

ABSTRACT

The novel SrTiO3/Bi5O7I nanocomposites were successfully fabricated by a thermal decomposition approach. The as-prepared samples were characterized by XRD, XPS, SEM, EDS, FTIR, DRS and PL spectra. The results show that the SrTiO3/Bi5O7I nanocomposites are composed of perovskite SrTiO3 nanoparticles and tetragonal Bi5O7I nanorods. The SrTiO3/Bi5O7I nanocomposites exhibit an excellent photocatalytic performance for the degradation of RhB solution under simulated solar light irradiation, which is superior to that of pristine Bi5O7I and SrTiO3. In particular, the 30 wt% SrTiO3/Bi5O7I nanocomposite is found as the optimal composites, over which the dye degradation reaches 89.6% for 150 min of photocatalysis. The photocatalytic degradation rate of the 30 wt% SrTiO3/Bi5O7I nanocomposite is found to be 3.97 times and 12.5 times higher than that of bare Bi5O7I and SrTiO3, respectively. The reactive species trapping experiments suggest that [Formula: see text] and holes are the main active species responsible for the RhB degradation. In addition, the PL spectra elucidate the effective separation of photoinduced electron-hole pairs. Further, the possible photocatalytic mechanism of the SrTiO3/Bi5O7I nanocomposites is also elucidated based on the experimental evidences.

10.
RSC Adv ; 8(10): 5441-5450, 2018 Jan 29.
Article in English | MEDLINE | ID: mdl-35542406

ABSTRACT

Novel multifunctional SrTiO3/NiFe2O4 nanocomposites were successfully fabricated via a two-step route. The as-prepared samples were characterized by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), field-emission transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy and vibrating sample magnetometry (VSM). The results indicate that the SrTiO3/NiFe2O4 heterostructures are composed of SrTiO3 spheroidal nanoparticles adhered to NiFe2O4 polyhedra. The heterojunction established in the composite material accelerates the process of electron-hole pair separation and boosts the photo-Fenton reaction. Among the samples, 15 wt% SrTiO3/NiFe2O4 nanocomposites exhibit a powerful light response and excellent room temperature ferromagnetism. Subsequently, the photocatalytic degradation of RhB over the as-prepared samples was investigated and optimized, revealing that the 15 wt% SrTiO3/NiFe2O4 nanocomposites exhibit the best photocatalytic activity and stability under simulated solar light irradiation. Furthermore, according to experimental results, the possible mechanism of improved photocatalytic activity was also proposed.

11.
RSC Adv ; 8(68): 39187-39196, 2018 Nov 16.
Article in English | MEDLINE | ID: mdl-35558322

ABSTRACT

Novel porous AgBr/Bi24O31Br10 (AB/BOB) heterojunction composites were prepared by a hydrothermal calcination-ion exchange route and their physico-chemical properties were characterized by XRD, XPS, SEM, EDX, UV-vis DRS, BET and electrochemical measurements. The photocatalytic activity of the composites consisting of different AB/BOB mass ratios was evaluated by degradation of methylene blue (MB) under visible light irradiation. Compared with pure AB and BOB, the porous 20% AB/BOB composite exhibits much enhanced photocatalytic activity with good cycling stability. The significant enhancement in photoactivity is contributed to by both a high adsorption capacity and the separation efficiency of photo-generated electron-hole (e--h+) pairs via a Z-scheme mechanism. In addition, radical scavenging experiments confirm that the reactive ·OH radicals play an important role in the photocatalytic reaction. The novel (AB/BOB) heterojunction composites could have a promising application in treatment of various dyestuff wastewaters on a large scale.

12.
Di Yi Jun Yi Da Xue Xue Bao ; 22(10): 951-2, 2002 Oct.
Article in English | MEDLINE | ID: mdl-12377632

ABSTRACT

OBJECTIVE: To study the clinical and pathological features of the polypoid lesion of the gallbladder (PLG) for making decisions for surgical treatment. METHODS: The clinical, pathological and imaging data of 244 cases of PLG were retrospectively analyzed. RESULTS: There were 235 benign polyps (96.31%) and 9 malignant polyps (3.69%) in all these cases, and most of the malignant polyps had a diameter greater than 1.0 cm, which often appeared as a single lesion in the cases. CONCLUSION: Surgical removal is indicated when the polyp appears as a single lesion with a diameter over 1.0 cm in patients older than 50 years, who may also have complications such as cholecysolithiasis or are exposed to other high-risk factors.


Subject(s)
Gallbladder Neoplasms/pathology , Gallbladder/pathology , Adult , Aged , Female , Gallbladder Neoplasms/classification , Gallbladder Neoplasms/physiopathology , Gallbladder Neoplasms/surgery , Humans , Male , Middle Aged , Retrospective Studies
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