Organic Pollutant Rhodamine Research Articles

Tetragonal/orthorhombic phase Bi2WO6 homojunction for photoelectrochemical degradation of rhodamine B with high efficiency

Photoelectrochemical (PEC) degradation of organic pollutants to CO2 and H2O is a promising strategy to solve the growing environmental problems. Bismuth tungstate (Bi2WO6) has attracted much attention due to its good chemical stability and moderate conduction band valence band position. However, the PEC activity of Bi2WO6 catalysts is greatly limited due to its rapidly complex electron-hole. This article reports a rational low-cost design that successfully prepares tetragonal/orthorhombic Bi2WO6 homojunction on FTO conductive glass substrates through a simple two-step solvothermal method, significantly enhancing the PEC performance. The study investigated the effectiveness of photoelectrochemical degradation of the recalcitrant organic pollutant Rhodamine B (RhB) and conducted an in-depth exploration of the photoelectrocatalytic reaction process and mechanism. The experimental results indicate that the homojunction achieves a degradation rate of up to 100 % for the recalcitrant organic pollutant RhB within 30 minutes, significantly surpassing that of single-phase Bi2WO6, and at the same time the sample maintains good stability after five cycles of operation. Further analysis of the capture experiments indicates that holes (h+) and superoxide radicals (·O2⁻) are the primary active species responsible for RhB degradation. This study not only provides new insights into the design of high-efficiency photoelectrode, but also offers new solutions for environmental pollution control.

Economical, one-pot, and green synthesis of plant-based carbon quantum dots for efficient visible-light photocatalytic dye degradation and water purification

BackgroundGreen, in-situ, one-pot, facile, and economical synthesis of efficient photocatalysts to destroy emerging aqueous contaminants is essential. MethodBiocompatible carbon quantum dots (CQDs) photocatalysts were successfully synthesized from a plant source called garden thyme as a low-cost precursor by one-step calcination method. CQDs were synthesized in both pure form and co-doped with fluorine and boron indicating size of <10 nm and favorable quantum yield of 40%. Four key factors including synthesis temperature, synthesis time, fluorine and boron weight ratios, and CQDs size were investigated on removal rates of organic pollutant Rhodamine B (RhB). Significant findings10%F-10%B co-doped CQDs with synthesized at 400 ºC for 5 h with a size of <10 nm, showed the highest photocatalytic RhB degradation performances of 86.1% and 89% within 40 and 60 min, respectively. This improved performance was originated from synergetic influences of quantum size, co-doping, promising quantum yield, and great visible light harvesting, that satisfactorily separated and transported light-created electron-hole pair. Trapping experimental data approved that hydroxyl radicals were dominant reactive species that oxidized RhB on F,B co-doped CQDs catalysts upon visible light radiation. Overall, CQDs could be easily synthesized as a green and super-cheap photocatalyst and would be effective for wastewater treatments.

Design of Environmental-Friendly Carbon-Based Catalysts for Efficient Advanced Oxidation Processes.

Advanced oxidation processes (AOPs) represent one of the most promising strategies to generate highly reactive species to deal with organic dye-contaminated water. However, developing green and cost-effective catalysts is still a long-term goal for the wide practical application of AOPs. Herein, we demonstrated doping cobalt in porous carbon to efficiently catalyze the oxidation of the typically persistent organic pollutant rhodamine B, via multiple reactive species through the activation of peroxymonosulfate (PMS). The catalysts were prepared by facile pyrolysis of nanocomposites with a core of cobalt-loaded silica and a shell of phenolic resin (Co-C/SiO2). It showed that the produced 1O2 could effectively attack the electron-rich functional groups in rhodamine B, promoting its molecular chain breakage and accelerating its oxidative degradation reaction with reactive oxygen-containing radicals. The optimized Co-C/SiO2 catalyst exhibits impressive catalytic performance, with a degradation rate of rhodamine B up to 96.7% in 14 min and a reaction rate constant (k) as high as 0.2271 min-1, which suggested promising potential for its practical application.

Efficient and stable immobilization of TiO2-based composite photocatalytic system for separation and purification of organic pollutants in wastewater under solar light

Photocatalytic removal of organic pollutants emerging from untreated industrial and aquaculture wastewater are still limited by catalytic efficiency and stability in practical application. In this study, we report the development of a silicone-immobilized, PEG-assisted Ag-doped TiO2 composite for efficient and sustainable removal of organic pollutants under solar irradiation. Firstly, a silicone-immobilized pristine TiO2 (S-TiO2) photocatalytic system was developed, demonstrating superior and stable removal of the organic pollutant Rhodamine B (Rh B) compared to PVA-TiO2 and dip-coated TiO2. Subsequently, pristine TiO2 was modified with the surfactant PEG, Ag species (Ag2O, Ag3PO4), and synthesized using the hydrothermal method, immobilized on silicone (S-H-PEG/PAgT). The S-H-PEG/PAgT, characterized by SEM, XRD, UV–Vis, and WCA revealed surface roughness, crystalline phase, excellent light absorption in the visible region, a narrow band gap, and hydrophobicity. The S-H-PEG/PAgT showed enhanced catalytic performance than S-TiO2 (Control) in the removal of tetracycline, a representative emerging organic contaminant. Furthermore, it displayed remarkable stability over 10 cycles and practicability in environmental conditions. Mechanism analysis revealed •O2– and h+ as the dominant active species involved in the catalytic reaction. Notably, a synergistic effect of surface hydrophobicity, roughness, and photocatalytic activity contributed to the reduction of pollutants. Therefore, the developed novel solar light driven S-H-PEG/PAgT photocatalytic system shows great promise for practical purification of organics pollutants in wastewater.

Porous rod-shaped Fe2O3/Ag/BP: a novel substrate for highly sensitive SERS detection of persistent organic pollutants

A surface enhanced Raman scattering (SERS) substrate of porous rod-shaped ferric oxide (Fe2O3) combined with silver nanoparticles (Ag NPs) and black phosphorus (Fe2O3/Ag/BP) was fabricated to detect the persistent organic pollutants (POPs) at low concentration. The organic pollutant Rhodamine 6G (R6G) was used as the probe molecule to study the performances of Fe2O3/Ag/BP, and 4-chlorobiphenyl (PCB-3) was the target of detection. The limit of detection (LOD) of R6G based on this novel SERS substrate Fe2O3/Ag/BP was as low as 1.0 × 10−15 M, which was five orders of magnitude lower than that of Fe2O3/Ag (10−10 M). The enhancement factor (EF) of Fe2O3/Ag/BP was 6.44 × 108, which was 3.1 times higher than that of porous rod-shaped Fe2O3/Ag (2.08 × 108). The Raman signal of R6G based on Fe2O3/Ag/BP had a good homogeneity, and the relative standard deviation (RSD) of Raman signal intensities of R6G at 1643 cm−1 was only 5.97%. Furthermore, the Fe2O3/Ag/BP substrate exhibited a recyclability through the photocatalytic degradation of R6G. The LOD of PCB-3 based on Fe2O3/Ag/BP was 10−9 M. Besides, Fe2O3/Ag/BP had a high SERS activity even it was kept in a centrifuge tube without requiring complicated treatment. These results highlight the potential application of Fe2O3/Ag/BP for ultra-trace detection of POPs in the environment.

Boosting Peroxymonosulfate Activation via CoS/MXene Nanocomposite for Rhodamine B Degradation under Simulated Sunlight Irradiation.

Cobalt-based heterogeneous catalysts have been demonstrated as an effective PMS activator for pollutant degradation. However, the limited active sites on their surface lead to an unsatisfactory catalytic efficiency. Immobilizing the catalysts on the support material can be a promising modification strategy to solve this problem. MXene has been considered as an ideal support material due to its unique morphology and physicochemical properties. Therefore, in this work, the CoS-loaded Ti3 C2 MXene (CoS/Ti3 C2 MXene) catalyst for peroxymonosulfate (PMS) activation was successfully synthesized through a solvothermal method. Under the simulated sunlight irradiation, the CoS/Ti3 C2 MXene+PMS system achieved an impressive efficiency in removing the organic pollutant rhodamine B (97.2 % in 10 min). Among the tested catalysts, 30 %-CoS-TC stood out, exhibited a broad pH tolerance from 5 to 9 and maintained robust degradation performance over cycles. Upon detailed analysis, the degradation mechanism revealed the collaborative action dominated by singlet oxygen, and supplemented by photogenerated holes and superoxide radicals in the process. Notably, the sandwich-like structure of MXene played a pivotal role, not only dispersing the CoS particles evenly on the surface of catalysts, but also providing ample space for the active sites, thus accelerating the PMS activation for the degradation of rhodamine B. Overall, this study developed an innovative MXene-based catalyst for the application of environmental remediation.

Preparation and characterization of Ag3PO4@g-C3N4 photocatalysts for dye wastewater treatment under visible-light irradiation

Ag3PO4@g-C3N4 photocatalyst was successfully prepared via a workable liquid phase deposition strategy. The Ag3PO4 particles were anchored intimately on the surface of g-C3N4 by the chemical bonding interactions. The obtained Ag3PO4@g-C3N4 heterojunction catalysts exhibit outstanding enhanced photodegradation performance and good stability for the removal of organic pollutants rhodamine B (RhB) and methyl orange (MO). And the as-synthesized Ag3PO4@g-C3N4 also displayed excellent stability for the photodegradation activity of RhB and MO in wastewater, and the performance remained above 90% after six cycles. The significant improvement of photocatalytic performance is attributed to the hereojunction structures derived from the interaction between Ag3PO4 and g-C3N4. The mechanism of the photocatalytic removal of RhB and MO dye was also investigated by the capture experiments and ESR spectra. Based on the research results, a new simple and feasible way for the preparation of Ag3PO4@g-C3N4 photocatalyst is provided for the degradation of organic pollutants in wastewater.

A facile synthesis of Bi2O3/SnS2 and Ag@Bi2O3/SnS2 nanostructures and their enhanced photodegradation application toward RhB

In this study, the binary Bi2O3/SnS2 (2 & 4 wt%) and ternary Ag (2, 4 & 6 wt%)@Bi2O3/SnS2 (2 wt%) nanostructures were prepared by the facile precipitation and deposition method. The synthesized materials were characterized by using several analytical methods such as X-ray diffraction, field emission scanning electron microscopy, energy dispersive X-ray, ultraviolet visible diffuse reflectance specctroscopy, photoluminescence, and X-ray photoelectron spectroscopy. The organic pollutant Rhodamine B (RhB) was used to determine the photocatalytic efficiency of prepared nanocomposites. Bi2O3/SnS2 and Ag@Bi2O3/SnS2 nanocomposites showed the maximum photocatalytic activity in acidic medium. As photocatalyst, ternary nanocomposite Ag (4 wt%)@Bi2O3/SnS2 (2 wt%) exhibited admirable performance (99.85% degradation in 40 min) in comparison to binary Bi2O3/SnS2 (2 wt%) nanocomposite for the degradation of RhB (98.95% degradation in 40 min). The enhanced activity was ascribed to the fabrication of Z-type heterojunctions which are beneficial for the effective separation of photoinduced charged species and decrease the recombination rate of charge carrier species. Also, the Ag (4 wt%) @ Bi2O3/SnS2 (2 wt%) photocatalyst showed magnificent stability after five cycles, in which the efficiency dropped by 5.31% only. The role of scavengers involved during the degradation reaction was conducted, and from this experimentation, the superoxide anion radicals and holes are found responsible dominant active species for the RhB degradation. This research work highlights the enhanced photocatalytic abilities and performance ofAg@Bi2O3/SnS2 for the elimination of organic pollutants such as RhB dye and it would exhibit the potential application in wastewater treatment.

A versatile nature of effective photocatalytic activity for degradation of the organic pollutant Rhodamine-B dye by PVA/ZnO/CuO nanocomposite

The photocatalytic degradation of dyes using metal oxides and their nanocomposites has been shown to be a smart technique for the detoxification of pollutants from the wastewater system. The desired PVA/ZnO/CuO nanocomposite was synthesized by the chemical precipitation method and characterized with XRD, FTIR, FESEM and UV–Visible spectroscopy. The X-ray diffraction depicts that the composite has poly-crystalline properties with multiphase heterojunctions. FTIR spectroscopy depicts the presence of functional groups of the polyvinyl alcohol polymer and metal oxides for the nanocomposite. FESEM depicts the surface morphology of the synthesized nanocomposite and the UV–Visible spectrum depicts photo-harvesting in the visible light region with a band gap of 1.68 eV for the catalyst. The photocatalyst degradation activity was examined against the organic pollutant Rhodamine B, which concluded a maximum efficiency of 71% degradation; the dynamic profile reached 0.28 (a.u.) in 90 min and the kinetic profile depicted a pseudo first order kinetic reaction rate R2=0.996. The results revealed that the synthesized PVA/ZnO/CuO nanocomposite showed enhanced effective photocatalytic activity under visible light.

Preparation of hierarchical self-assembled SiO2/ZnO composite by low-temperature hydrothermal approach for enhanced adsorption of 4-nitrophenol and dyes

Here, we initially fabricated the hierarchical SiO2/ZnO nanospheres via a facile low temperature (LT) 90 °C hydrothermal approach and the prepared SiO2/ZnO nanospheres show an excellent surface area of about 1280.8 m2/g. The prepared composite has been investigated for the removal of mixture of cationic (rhodamine B, crystal violet, methylene blue) and anionic dyes (congo red, methyl orange) to understand the industrial point of view. On the basis of the selectivity test, a detailed study has been carried out for the removal of organic pollutant Rhodamine B, and the effect of pH, contact time, initial dye concentration, and adsorbent dosage were among the optimal parameters that led to the maximum RhB adsorption (pH-11, 10 min, and 5 mg of adsorbent). It has been noticed that SiO2/ZnO shows an impressive adsorbent property for basic cationic dyes. The ability of the SiO2/ZnO adsorbent to be reproduced and reused was evaluated. Furthermore, the produced adsorbent was known to adhere to pseudo-second-order kinetics and the Langmuir isotherm with R2 = 0.96 and R2 = 0.98, respectively. The catalytic property of the prepared material was also tested for 4-nitrophenol reduction using NaBH4. The adsorption capacity (max.) for the removal of RhB was reported to be 83.33 mg/g, and on the other hand, 4-NP was 89% removed by the prepared adsorbent. The experiments confirmed that the processed nanocomposite can successfully eliminate organic pollutants, implying the practical applicability of the material for waste-water remediation.

Facile synthesis of activated biochar/BiVO4 heterojunction photocatalyst to enhance visible light efficient degradation for dye and antibiotics: applications and mechanisms

The applications of biochar in catalysis have become a research hotspot, but studies using activated biochar (ACB) and enhanced mechanisms are limited. To improve the photocatalytic performance of BiVO4, the nano-photocatalyst (ACB-BiVO4) was synthesized via a facile hydrothermal reaction. Various characterization techniques were performed, and the adsorption-photodegradation of the organic pollutants rhodamine B (RhB), tetracycline (TC), norfloxacin (NOR), and chloramphenicol (CAP) under visible light were investigated. Meanwhile, the effects of loading ratios, initial concentrations, recycling tests, more enhancement strategies, actual wastewater treatment, and disinfection effects on photocatalysis of ACB-BiVO4 were comprehensively evaluated. The results confirmed that the tetragonal phase BiVO4 was successfully composited onto the support ACB forming heterojunction, which displayed the best performance at a mass ratio of 1:0.62. The degradation rate by ACB-BiVO4 reached 84.52% for RhB at a kinetic constant of 0.0133 min−1, which was 5.78 times higher than pure BiVO4. ACB-BiVO4 completely removed RhB and TC from the investigated surface water and removed more than 73.50% of RhB and TC from industrial wastewater. ACB-BiVO4 had excellent disinfection effects on E. coli and Staphylococcus aureus with a sterilization rate of over 99% at 12 h ·OH and holes were dominant active species and the enhancement mechanism is associated with the heterojunction. ACB-BiVO4 expanded the visible light (∼545 nm) absorption and reduced the band gap (2.26 eV), and effectively inhibited the photogenerated carriers recombination. The unique structure (defects) and surface properties (functional groups and environmentally persistent free radicals) of ACB were found to play a critical role.

Facile hydrothermal synthesis of co-glycerate as an efficient peroxymonosulfate activator for rhodamine B degradation

Sulfate radical based advanced oxidation processes (SR-AOPs) are regarded as a promising technology to degrade organic pollutants in water. Here, hydrothermally synthesized Co-glycerate (Co-G) microspheres are proposed as an efficient heterogeneous catalyst to activate peroxymonosulfate (PMS) for degradation of refractory organic pollutant rhodamine B (RhB) in aqueous solution. The presence of Co-G microspheres enhanced the degradation rate significantly with a short full degradation time (8 min) and a total organic carbon (TOC) removal exceeding 41% (10 min), thus implying the excellent catalytic performance of Co-G microspheres for PMS activation. Furthermore, the effects of PMS and catalyst concentration, initial pH value and co-existing ions on RhB degradation were investigated. Radical quenching and EPR tests identify that active species including SO4-·, HO·, O2-· and 1O2 are involved in the degradation process. Additionally, a possible reaction mechanism of PMS activation by Co-G microspheres for RhB degradation was suggested. This study can provide a new insight for design of cobalt-based heterogeneous catalysts as activators to activation PMS for pollutants degradation.

The stable and elastic graphitic carbon nitride/polyvinyl alcohol photocatalytic composite sponge: Simple synthesis and application for wastewater treatment

Nanosized photocatalysts have the obvious disadvantages in recovering and recycling process during the wastewater treatment. To overcome the above shortcomings, graphitic carbon nitride/polyvinyl alcohol (g-C3N4/PVA) photocatalytic composite sponge was prepared simply by introducing graphitic carbon nitride (g-C3N4) photocatalyst into polyvinyl alcohol (PVA) sponge via copolymerization method during the cross-linking process. The characterization results indicated that the g-C3N4/PVA composite sponge has the porous structure and g-C3N4 nanoparticles have been attached uniformly and tightly throughout the porous structure of the PVA sponge. Furthermore, the composite sponge has excellent elastic deformation property and can be easily tailored into designed shapes without destroying the structure of the sponge. Thirdly, the composite sponge shows efficient adsorption and photodegradation properties for removing of organic pollutants rhodamine B (RhB) and tetracycline (TC) from wastewater. It is worth to note that the prepared g-C3N4/PVA composite sponge can be easily recovered from the wastewater solution and shows stable recycling property. Our method to combine g-C3N4 photocatalysts into PVA sponge provides a facile technique to construct stable photocatalysts with recyclable and photocatalytic degradation properties in the field of wastewater treatment.

Construction of black phosphorus nanosheets and Ag nanoparticles co-sensitized TiO2 nanorod arrays as high-performance SERS substrate and photocatalyst

In this study, high-performance surface-enhanced Raman scattering (SERS) substrates and photocatalysts based on TiO2 nanorod (TNR) arrays co-sensitized with black phosphorus (BP) nanosheets and Ag nanoparticles were successfully synthesized. The detection limit of the organic pollutant rhodamine 6G (R6G) on this novel SERS substrate was as low as 1.0 × 10−14 M. The calculated enhancement factor (EF) was as high as 3.81 × 105. These results prove the excellent SERS sensitivity of the BP/Ag/TNR substrate. Furthermore, a good uniformity of the signals was observed during the detection process. The relative standard deviation of the intensity of the Raman fingerprint peak of R6G at 1650 cm−1 was only 8.41%. Moreover, the BP/Ag/TNR substrate exhibited self-cleaning abilities through the photocatalytic degradation of the adsorbed R6G molecules. The BP/Ag/TNR substrate exhibited a maximum rate of 93.5% for the photocatalytic degradation of R6G. The corresponding photodegradation rate constant was 34.2 × 10−3 min−1, which was approximately 3.98 and 2.01 times higher than those of the TNR and Ag/TNR arrays. The improved SERS performance and excellent photocatalytic activity of the BP/Ag/TNR substrate was due to the formation of high-density hot spots, expansion of the optical capture abilities, and enhancement of the charge transfer properties.

Impact of bandgap tuning on ZnS for degradation of environmental pollutants and disinfection.

The materials showing multiple applications are appealing for their practical use and industrial production. To realize the suitable property for various applications, we have produced ZnS (sf-ZnS) and metal-doped ZnS nanoflakes (sf-m-ZnS; where m = Cu, Ni, Cd, Bi, or Mn) and correlated their activity with bandgap variation. We obtained all these materials via hexamethyldisilazane (HMDS)-assisted synthetic method without using any surfactants, polymers, or template molecules and characterized them thoroughly using various techniques. Photocatalytic, as well as antibacterial, activities of these materials showed their bifunctional utility. We have demonstrated the effect of doping and consequent extension of absorption band to the visible region and resultant improved photocatalytic activity under sunlight. Thus, the change in bandgap influenced their performance as photocatalysts. Among all materials produced, sf-Cd-ZnS provided superior results as a photocatalyst while degrading two organic pollutants-rhodamine B (RhB) and methylene blue (MB) in water. The antibacterial activity of sf-ZnS and sf-m-ZnS against Gram-positive bacteria, i.e., Staphylococcus aureus (S. aureus), was examined by the zone of inhibition method, wherein sf-Ni-ZnS showed maximum activity. The enhanced activity of these ZnS materials can be attributed to the free surface of nanoparticles without any capping by organic molecules, which provided an intimate interaction of inorganic semiconductor material with organic and biomolecules. Thus, we have demonstrated modification of properties both by bandgap tuning of materials and providing the opportunity for intimate interaction of materials with substrates. The photocatalytic activity and antibacterial action of metal-doped ZnS produced by our method exhibited their potential for environmental remediation, specifically water purification.

Effluent degradation capability of polygonal MnCo2O4 spinel fabricated using guava leaf extract as green fuel

This work reports green synthesis of heterometalic MnCo2O4 nano-cobaltite using Psidium guajava leaf extract as chelating agent as well as reducing agent. An eco-friendly pathway is adopted for microstructural, optical and effluent degradation properties of the synthesized nano-polygonal material. Microstructural and optical characterization of the prepared material was done using X-Ray Diffractometer, FESEM and UV–Vis spectroscopy. XRD pattern confirms successful formation of the phase pure sample and Rietveld analysis of the XRD gives different microstructural parameters (lattice parameter, crystallite size and microstrain). FESEM micrograph shows polygonal morphology of the nano-particles and UV–Vis spectra analysis confirms its band gap value within the semiconducting range. To examine the photocatalytic degradation capability of the prepared bio-sample, fabricated nano-material is used as catalyst for degradation of model organic pollutant Rhodamine B. Fabricated MnCo2O4 bio-sample shows excellent catalytic efficiency of ∼ 85.83% for solution of Rhodamine B pollutant in 140 min under visible light irradiation. This non-toxic, eco-friendly green approach to fabricating MnCo2O4 has potential application and effectiveness as suitable catalyst in organic effluent degradation released from textile industries.

Enhanced photocatalytic performance of cauliflower-like CeO2-TiO2 nanocomposite for the RhB dye degradation under visible light

This work has investigated the photocatalytic activity of the CeO2-TiO2 nanocomposites synthesized by mechanical alloying with different molar ratios of CeO2:TiO2 powders within 5 h of milling. The structure, microstructure and content of all crystalline phases identified in the milled nanocomposites are revealed by analyzing the XRD patterns employing the Rietveld refinement technique and FTIR spectra. The morphology of the nanocomposites is investigated by analyzing FESEM images. The UV–vis absorbance spectra of the samples have revealed the optical bandgaps and photocatalytic behaviours of all prepared nanocomposites. The photodegradation of a model organic pollutant Rhodamine B (RhB) has been investigated using a UV–vis spectrophotometer under visible light illumination. About 63% of RhB has been degraded under visible light in the presence of the 20CeO2-80TiO2 (2Ce8Ti-5 h) nanocomposite within 240 min. The multicycle test of the 2Ce8Ti-5 h nanocomposite shows the reusability of the as-prepared photocatalyst. Thus, this nanocomposite can be used as an effective photocatalytic for removing organic dye from wastewater.

Highly Luminescent, Stable, and Red-Emitting CsMgxPb1-xI3 Quantum Dots for Dual-Modal Imaging-Guided Photodynamic Therapy and Photocatalytic Activity.

In this study, for the first time, red-emitting CsMgxPb1-xI3 quantum dots (QDs) are prepared by doping with magnesium (Mg) ions via the one-pot microwave pyrolysis technique. The X-ray diffraction and X-ray photoelectron spectroscopy results have confirmed partial substitution of Pb2+ by Mg2+ inside the CsPbI3 framework. The as-synthesized CsMgxPb1-xI3 QDs have exhibited excellent morphology, higher quantum yield (upto ∼89%), better photostability and storage stability than undoped CsPbI3. Next, the bioavailability of as-synthesized hydrophobic CsMgxPb1-xI3 QDs is improved by encapsulating them into gadolinium-conjugated pluronic 127 (PF127-Gd) micelles through hydrophobic interactions (PQD@Gd). The optical properties of perovskite quantum dots (PQDs) and the presence of Gd could endow the PQD@Gd with fluorescence imaging, magnetic resonance imaging (MRI), and phototherapeutic properties. Accordingly, the MRI contrasting effects of PQD@Gd nanoagents are demonstrated by employing T1 and T2 studies, which validated that PQD@Gd nanoagents had superior MR contrasting effect with a r2/r1 ratio of 1.38. In vitro MRI and fluorescence imaging analyses have shown that the PQD@Gd nanoagents are internalized into the cancer cells via a caveolae-mediated endocytosis pathway. The PQD@Gd nanoagents have exhibited excellent biocompatibility even at concentrations as high as 450 ppm. Interestingly, the as-prepared PQD@Gd nanoagents have efficiently produced cytotoxic reactive oxygen species in the cancer cells under 671 nm laser illumination and thereby induced cell death. Moreover, the PQD@Gd nanoagent also demonstrated excellent photocatalytic activity toward organic pollutants under visible light irradiation. The organic pollutants rhodamine b, methyl orange, and methylene blue were degraded by 92.11, 89.21, and 76.21%, respectively, under 60, 80, and 100 min, respectively, irradiation time. The plausible mechanism for the photocatalytic activity is also elucidated. Overall, this work proposes a novel strategy to enhance the optical properties, stability, and bioapplicability of PQDs. The multifunctional PQD@Gd nanoagents developed in this study could be the potential choice of components not only for cancer therapy due to dual-modal imaging and photodynamic therapeutic properties but also for organic pollutant or bacterial removal due to excellent photocatalytic properties.

Fluorinated inverse opal carbon nitride combined with vanadium pentoxide as a Z-scheme photocatalyst with enhanced photocatalytic activity

In this work, Z-scheme V2O5 loaded fluorinated inverse opal carbon nitride (IO F-CN/V2O5) was synthesized as a product of ternary collaborative modification with heterostructure construction, element doping and inverse opal structure. The catalyst presented the highest photocatalytic activity and rate constant for degradation of typical organic pollutants Rhodamine B (RhB) and was also used for the efficient removal of antibiotics, represented by norfloxacin (NOR), sulfadiazine (SD) and levofloxacin (LVX). Characterizations confirmed its increased specific surface area, narrowed bandgap, and enhanced visible light utilization capacity. Further mechanism study including band structure study and electron paramagnetic resonance (EPR) proved the successful construction of Z-scheme heterojunction, which improved photo-generated charge carrier migration and provide sufficient free radicals for the degradation process. The combination of different modifications contributed to the synergetic improvement of removal efficiency towards different organic pollutants.

Metal free benzothiadiazole-diketopyrrolopyrrole-based conjugated polymer/g-C3N4 photocatalyst for enhanced sterilization and degradation in visible to near-infrared region

In recent years, photocatalytic technology has attracted wide attention in environmental treatment, exploring non-toxic and metal-free photocatalysts is imminent to meet sustainable development. However, semiconductors with wide spectral response are rarely studied and applied in the field of photocatalysis. Herein, a new narrow band-gap polymer PFBDT-DPP (P3) with wide absorption from 500 to 860 nm was synthesized and further constructed heterostructure with g-C3N4 for photocatalytic sterilization and degradation of organic pollutant Rhodamine B (RhB). The optimal antibacterial rate for Escherichia coli reached 99.8% after 190 min of light irradiation and for Staphylococcus aureus reached 96.8% after 120 min of irradiation, and the highest degradation efficiency of RhB by P3/g-C3N4 was 98.9% within 60 min light irradiation, while g-C3N4 displayed an unsatisfactory sterilization and photodegradation performance. This is mainly attributed to the broadened light absorption range and enhanced carrier separation efficiency of P3/g-C3N4. This work could provide a new strategy to fabricate metal-free photocatalysts with high utilization of sunlight and excellent photocatalytic performance.