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•A thiophene was successfully introduced to a reticulated polyamide with tri(4-aminophenyl)benzene.•The polyamide containing thiophene and tri(4-aminophenyl)benzene exhibits high ...selectivity and reproducibility for Hg2+.•Spectroscopic techniques and DFT calculations revealed the main adsorption mechanism of TPPA on Hg2+.
In this study, the thiophenyl polyamide (TPPA) derived from tri(4-aminophenyl) benzene was synthesized for the removal of Hg2+ from the aqueous solution. The adsorbent was characterized by the Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscopy, nitrogen adsorption–desorption, thermogravimetric analysis and differential scanning calorimetry. The adsorption capacity of Hg2+ is 518.7 mg g−1 at a dose of 1.1 g/L of adsorbent. TPPA was shown to have the following advantages: (i) the high selectivity for the excess metal ions Hg2+, (ii) the stability in the pH values ranging between 2 and 6, and (iii) the proper recyclability (87 % of Hg2+ can be removed in 5 adsorption–desorption cycles). Our analysis suggests the models of the pseudo-second-order kinetics and the Langmuir isotherm are suitable for the description of the adsorption of Hg2+ on the thiophene network polyamide. Our experimental and theoretical results reveal the relationship between the structures and the adsorption capacities of TPPA, identifying the oxygen atom (amide) and the sulphur atom (thiophene) as the most important chemical-reaction sites.
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•A novel 2D/2D WO3/BiOBr S-scheme heterojunction has been prepared.•The synergistic effect of photocatalysis and PMS activation based on WO3/BiOBr heterojunction was ...explored.•WO3/BiOBr can remove 98% of TC and 87% of ENR in 60 min with PMS assisting under visble light.•The internal electric field and band edge bending are explained based on the results of DFT calculation.••O2−, h+ and 1O2 were the main radicals for TC and ENR degradation.
The Sulfate-mediated photocatalysis (SR-photo) technology was considered to be a rapid, efficient and green environmental treatment technology. In this study, the two-dimensional/two-dimensional WO3/BiOBr S-scheme heterojunction (2D/2D WOB) were prepared through the hydrothermal method. Subsequently, multiple characterization techniques confirmed that WO3 was successfully loaded on the surface of BiOBr nanosheets and an intimate interaction was formed. Tetracycline (TC) and enrofloxacin (ENR) were used as target pollutants to evaluate the degradation performance of the WOB/SR-photo system. The 1:2 WOB heterojunction exhibited the highest degradation activity, and the remove rate of TC and ENR reached 98% and 87%, respectively, within 60 min. Moreover, radical quenching experiments and electron paramagnetic resonance (EPR) results implied that the 1O2, h+, and ·O2 − played critical roles in the WOB/SR-photo system. The intermediate products of TC degradation were analyzed by liquid chromatography-mass spectrometer (LC-MS), and three possible degradation pathways were inferred. The photoelectrochemical measurement, photoluminescence (PL) and time-resolved PL confirmed that 1:2 WOB composite exhibited the highest transfer rate of charge carriers. Finally, based on the results of UV-DRs, Mott-Schottky curve and Density functional theory (DFT) calculations, the S-scheme WOB heterostructure was determined, and the degradation mechanism of the WOB/SR-photo system was also clarified. This study confirmed the superiority of the SR-photo system and brought dawn to the application of numerous photocatalysts with insufficient performance.
Transition metal doped ZnO (TM-ZnO) nanoparticles with 3% dopant content are successfully prepared via a simple solvothermal route. This work highlights Mn, Fe, Co, Ni or Cu ions as the dopant ...transition metals. The as-prepared samples are wurtzite phase ZnO crystals, and the average sizes of undoped ZnO and TM-ZnO nanoparticles range from 200 nm to 400 nm. XPS studies confirm that the transition metal ions are successfully doped into the crystal lattice of ZnO. The band gaps of the undoped ZnO and TM-ZnO crystals are calculated by using UV-DRS spectroscopic measurements. The visible light response of ZnO nanomaterials is improved by doping transition metal ions. For investigating the influence of transition metal doping on the photocatalytic performance of ZnO, the photodegradation rate of methylene blue (MB) is investigated under simulated sunlight irradiation. The photocatalytic properties of ZnO doped with transition metals are improved at different degrees, among which Cu-doped ZnO exhibits the best photocatalytic performance. Based on density functional theory (DFT) calculation result, a possible photocatalytic mechanism is proposed. Furthermore, the antibacterial performance of Cu-doped ZnO is investigated by selecting E. coli, under simulated sunlight irradiation and remarkable sterilization of E. coli is achieved.
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•Transition metal doped ZnO nanoparticles were successfully prepared.•The visible light response of ZnO nanomaterials was improved.•The photocatalytic activities of ZnO doped with transition metals were improved.•Cu-doped ZnO shows remarkable sterilization of E. coli.
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•The dual Z-scheme photocatalysts with phase junction WO3 and CdS were fabricated.•The 75CW has the best photocatalytic rate of imidacloprid degradation.•The Fukui indexes were ...exploited to predict reactive sites.•The reliable degradation pathways of imidacloprid were proposed.
The construction of dual Z-scheme photocatalysts is an effective way to promote the separation and migration of electrons-holes as well as retain their high redox abilities. Herein, a distinctive dual Z-scheme photocatalyst based on phase junction WO3 and CdS (CW) was successfully fabricated via hydrothermal method and in-situ precipitation process. The as-prepared materials showed the advantages of both phase junction and dual Z-scheme mechanism (promoted utilization of carriers and improved redox potential). As a result, the kapp value of 75CW (0.05237 min−1) was 29.8 times that of phase junction WO3 (0.00176 min−1) and 2.9 times that of CdS (0.01799 min−1) in terms of imidacloprid (IMD) degradation. Trapping experiment and electron spin resonance (ESR) proved the dual Z-scheme mechanism, the key to significantly improve photocatalytic degradation efficiency of WO3/CdS nanocomposites. Combined the analysis of liquid chromatography-mass spectrometry (LC-MS) with density functional theory (DFT) calculation, rational degradation pathways of IMD were put forward in detail. This work is excepted to provide new horizons for the construction of dual Z-scheme system with phase junction and the photodegradation of IMD.
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•In-situ construction of Co(OH)2 nanoparticles decorated urchin-like WO3 was obtained.•Co(OH)2/WO3 showed high catalytic activity for removing SCP by PMS activation.•Co(OH)2/WO3 ...induced formation of the key PMS activation species CoOH+.•SCP atoms with high Fukui index (f−) were easily attacked by the SO4•− and HO•.
Sulfachloropyridazine (SCP) was commonly used as a broad-spectrum sulfonamide antibiotic and hard to be removed through traditional sewage treatment process. In this study, we developed a simple and controllable strategy to realize in-situ construction of Co(OH)2 nanoparticles decorated urchin-like WO3 (Co(OH)2/WO3), which could efficiently remove SCP through peroxymonosulfate (PMS) activation. Some tiny nanoparticles of Co(OH)2 decorated on the spines/nanorods or surfaces of urchin-like WO3 by transmission electron microscopy (TEM) analysis. The obtained 10 wt% Co(OH)2/WO3 realized completely removal of SCP (degradation efficiency 100%) with a high reaction rate constant (k1) of 0.88 min−1 within 3 min at optimal pH 7. That was because the urchin-like WO3 with numerous adsorption functional groups on its surface (e.g., W = O and –OH bonds) could adsorb the Co2+ easily to form CoOH+, which was perceived the rate-limiting step for PMS activation and generating radicals. Radical quenching experiments indicated that SO4•− played a more significant role than HO• radicals. Density functional theory (DFT) calculation revealed that the atoms of SCP with high Fukui index (f−) were active sites, which preferred to be attacked by the electrophilic SO4•− and HO• radicals. The toxicity of the intermediates by SCP degradation was evaluated by quantitative structure–activity relationship (QSAR) prediction through Toxicity Estimation Software Tool (T.E.S.T.). The possible degradation pathway and catalytic mechanism for SCP removal were proposed. Considering the good catalytic properties of Co(OH)2/WO3-PMS, the material will show great application potential in the removal of emerging contaminants in water.
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•Four hundred low-energy isomers of Rh6NO+ were found and characterized using density functional theory calculations.•They were classified based on the geometry of Rh6, the adsorption ...form and site of NO, and the spin state.•For molecular adsorption of NO on Rh6+, on-top binding is dominant, which is consistent with the experimental IR spectrum.•Dissociative adsorption leads to significant influence on the geometry, expressed by a large number of isomers with low energy barriers connecting them.
The adsorption of an NO molecule on a Rh6+ gas phase cluster was investigated based on a wide screening of the geometrical and spin isomers by density functional theory calculations. For molecular adsorption, several different on-top adsorption forms were found in a wider energy range. For dissociative adsorption, a characteristic adsorption form was found, which has many more geometrical and spin isomers than the other adsorption forms. These isomers can exist because of the relative flexible geometric structure, in which a Rh atom is connected to pyramidal Rh5 through two hinge-like connections formed by the N and O atoms.
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•Optimum proportion of benzoic acid for synthesis of more defects UiO-67.•Defects, methyl and benzene ring enhance π-π interaction to promote VOCs adsorption.•Multiple experiments and ...DFT calculation analyze interaction between VOCs and MOFs.
The harm that is caused by volatile organic compounds (VOCs) has attracted worldwide attention. In production, industrial processes such as fossil fuel combustion, plastics, and paints have caused complex and diverse VOCs emissions. Therefore, studying the phenomenon and influencing factors of typical VOCs adsorption is of practical significance for the treatment of multicomponent VOCs. In this work, defective UiO-67 was prepared by changing the amount of benzoic acid. Then, the adsorption performance was tested, and the adsorption kinetics were considered. The experimental results showed that the 67-ben-10 sample (for which the molar ratio of Zr4+ to benzoic acid was 1:10) achieved the maximum toluene adsorption capacity (480 mg g−1), which was due to the presence of more adsorption sites, higher benzoate content, strong π-π stacking and excellent adsorption diffusion behavior. In addition, the adsorption properties of the 67-ben-10 benzene series (BTX: benzene, toluene, o-xylene, p-xylene and m-xylene) and acetone were further investigated. The results showed that the adsorption performance was related to the polarizability of the VOCs molecules, the method of pore entry and the molecular size. Finally, through desorption experiments, density functional theory (DFT) and kinetics, the binding energy was confirmed to play an important role in adsorption and diffusion.
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In this paper, a simple solvothermal synthesis method was proposed for the preparation of metal organic framework/graphene oxide hybrid nanocomposite (UiO-67/GO). A series of ...UiO-67/GO composites were prepared by varying the addition forms and amounts of GO, and the optimal synthesis conditions were screened. The composites were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), transmission Electron Microscope (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopic (XPS), water contact angles (CA) and thermogravimetric analysis (TGA). The adsorption capacity and the adsorption process of toluene were investigated by dynamic adsorption and adsorption kinetics, respectively. The results indicated that 67/GO-0.5% reached the maximum adsorption capacity (876 mg g−1), which far exceeded the other adsorbents. Kinetic model and the Weber-Morris model correlated satisfactorily to the experimental data. The improved adsorption performance was attributed to GO, which enhanced π-π interaction, promoted defect generation and provided more adsorption sites. Finally, the excellent regeneration performance of the adsorbent was verified by temperature programmed desorption (TPD) and cyclic adsorption–desorption experiments. Moreover, the adsorption mechanism was further revealed. Combined with the related adsorption experiments and the density functional theory (DFT) analysis, the efficient removal of toluene by UiO-67/GO was attributed to the cooperation of defects, π-π interaction and hydrogen bonding.
