Removal Of Tetracycline Hydrochloride Research Articles

Synergistic effect of iron and nitrogen on porous carbon to improve electron transfer efficiency resulting in the enhancement of tetracycline hydrochloride removal

Developing transition metal/nitrogen carbon catalysts for efficient pollutant removal presented an attractive option for water environment remediation. In this work, the iron (Fe), nitrogen (N) co-doped porous carbon nanoparticles (FeN/C) were prepared for heterogeneous activation of peroxymonosulfate and efficient oxidation of tetracycline hydrochloride (TC). Fe nanoparticles were encapsulated in the carbon to reduce the loss of Fe during the catalysis processes. As a catalyst, the sample of 20FeN/C exhibited an excellent catalytic activity of tetracycline hydrochloride with a removal rate of 91.2 % and a rate constant of 0.6653 min−1 in peroxymonosulfate (PMS) system. And the prepared catalysts presented the strong adaptability, which was worked efficient in a wide range pH and some anions solution. The high efficiency could attribute to the interaction of Fe and N, which effectively improved the electron transfer efficiency in this 20FeN/C activated PMS system. Combining with the results of electron paramagnetic resonance (EPR), in-situ Raman spectra, and X-ray photoelectron spectroscopy (XPS), electrons transfer was confirmed as a dominating non-radical process of TC degradation. It was confirmed that the doping of iron and nitrogen could collectively promote the electron transfer between material and PMS, and the activated PMS* reacted with TC via electron-rich nitrogen active sites of the material surface, then the TC degradation was enhanced. The received finding is of great significance to supplement the mechanism of electron transfer and provides a new idea on the synthesis of iron/nitrogen co-doped carbon catalysts to achieve high efficiency of TC removal.

Covalently grafting porphyrin on SnO2 nanorods for hydrogen evolution and tetracycline hydrochloride removal from real pharmaceutical wastewater with significantly improved efficiency

The sensitization of a wide-gap oxide semiconductor with a strong visible-light-absorbing porphyrin has been evidenced as a promising approach to craft highly efficient photocatalysts towards photocatalytic hydrogen evolution and environmental remediation. However, the practical utilization of porphyrins-sensitized oxide catalysts relies on the integration mode between porphyrins and metal oxide. Herein, a novel high-performance porphyrin-sensitized oxide catalyst is constructed via covalent assembling of copper porphyrin derivative of 5-(4-azidophenyl)-10,15,20-triaminoporphyrin (CuTPP–N3) on SnO2 nanorods by click reaction for the first time. The optimized 10 %CuTPP-N3/SnO2 hybrid demonstrates remarkably enhanced photocatalytic activity in H2 evolution of 658.6 μmol g−1h−1. It is almost 78 times higher than that of pristine SnO2. It also exhibits great potential for eliminating tetracycline hydrochloride (TCH) from various aqueous solutions with high durability under visible-light irradiation. Its removal rates in deionized water, tap water and real pharmaceutical wastewater are 90.5%, 72.2% and 85%, respectively. It is almost 13 times higher than that of pristine SnO2 nanorods in deionized water. The experimental evidence indicates that the highly conjugated linker between CuTPP–N3 and SnO2 plays a critical role for facilitating photoinduced electron transfer ability. This forms an efficient Z-scheme carrier transmission system in the hybrid. Therefore, the present work affords a well-designed molecule-engineered chromophore/oxide hybrid for highly efficient application in hydrogen evolution and environmental remediation.

Facile fabrication of Eu-based metal–organic frameworks for highly efficient capture of tetracycline hydrochloride from aqueous solutions

The tetracycline hydrochloride (TCH) removal from wastewater is important for the environment and human health yet challenging. Herein, the Eu-based MOF, Eu(BTC) (BTC represents 1,3,5-trimesic acid) was prepared by an efficient and environmental-friendly strategy, and then was used for the TCH capture for the first time. The Eu(BTC) was characterized by different methods such as X-ray diffraction, scanning electron microscopy and Fourier-transform infrared spectroscopy. The TCH uptake of Eu(BTC) was investigated systematically. The influences of experiment conditions such as solution pH value, adsorption time and initial concentration on TCH capacity of Eu(BTC) were also studied. The Eu(BTC) obtained exhibited remarkable TCH uptake (qm was up to 397.65 mg/g), which was much higher than those of most materials such as UiO-66/PDA/BC (184.30 mg/g), PDA-NFsM (161.30 mg/g) and many carbon-based materials reported till now. Besides, the TCH adsorption behavior on Eu(BTC) was explored by Freundlich and Langmuir equations, and the adsorption mechanism was further analyzed. The experimental results suggested that the TCH adsorption mechanism of Eu(BTC) included the π–π interaction, electrostatic interaction and coordinate bonds. The excellent TCH adsorption performance and the efficient fabrication strategy make the Eu(BTC) prepared promising in TCH removal.

3D/2D CuBi2O4@Bi2O2CO3 Z-scheme heterojunction: The construction of adsorption-photocatalytic synergistic effect for tetracycline hydrochloride removal

To solve the contamination of organic antibiotics in water environment, the 3D/2D CuBi2O4@Bi2O2CO3 (CBO@BOC) hierarchical structure was constructed through the in situ growth of Bi2O2CO3 nanosheets on the surface of CuBi2O4 microspheres. The performance of the as-prepared CBO@BOC composites for the removal of tetracycline hydrochloride (TCH) was investigated by varying the composition ratio, pH of the reaction system, initial pollutant concentration and anion interference. With the synergistic effects of adsorption and photocatalysis, the removal efficiency of CBO@BOC hierarchical composites was significantly improved, which achieved 90% for 20 mg/L TCH. In addition, the CBO@BOC composite also maintained excellent removal ability for TCH in different actual environments and exhibited good cycling stability. In the photocatalytic process,·O2- and h+ acted as the main active components to fully oxidize TCH, which constructed Z-scheme heterojunction photocatalysis mechanism. This work pointed out a new perspective on hierarchical heterostructure for the effective removal of organic antibiotic contaminants via synergistic adsorption and photocatalysis effect.

Removal of tetracycline hydrochloride by N, P co-doped carbon encapsulated Fe2P activating PMS: A non-radical pathway dominated by singlet oxygen

Metal phosphides are effective in environmental catalysis to remove pollutants. Herein, a novel magnetic material of Fe2P nanoparticles encapsulated in N, P-doped carbon (Fe/P-NPGC) was successfully fabricated as a peroxymonosulfate (PMS) activation catalyst. Benefiting from the electron-donating ability of Fe2P, Fe/P-NPGC consistently maintains over 90% removal rate of tetracycline hydrochloride (TCH) over a wide pH range. Based on quenching experiments and characterizations, we propose that Fe2P not only activates PMS to generate reactive oxygen species but also promotes Fe (II) regeneration, thus improving the activation efficiency of PMS and generating an efficient non-radical pathway dominated by 1O2. Both Fe2P and graphitic N have excellent interfacial electron transfer efficiency, which improves the self-decomposition activation of PMS to generate 1O2. The catalyst has excellent stability and adaptability under inorganic ions interference and real water environment, indicating that it has excellent potential for practical wastewater treatment.

Visible-light-driven AgI/Bi4O5I2 S-scheme heterojunction for efficient tetracycline hydrochloride removal: Mechanism and degradation pathway

The existence of excessive tetracycline hydrochloride (TCH) in the ecological environment has seriously threatened human health, so there is an urgent need to develop a high-performance photocatalyst that can efficiently and greenly remove TCH. Currently, most photocatalysts have the problems of fast recombination of photogenerated charge carriers and low degradation efficiency. Herein, S-scheme AgI/Bi4O5I2 (AB) heterojunctions was constructed for TCH removal. Compared with the single component, the apparent kinetic constant of the 0.7AB is 5.6 and 10.2 time as high as the AgI and Bi4O5I2, and the photocatalytic activity only decreases by 3.0% after four recycle runs. In addition, to verify the potential practical application of the fabricated AgI/Bi4O5I2 nanocomposite, the photocatalytic degradation of TCH was performed under different conditions by regulating the dosage of photocatalyst, the TCH concentration, pH, and the existence of various anions. Systematical characterizations are conducted to investigate the intrinsic physical and chemical properties of the constructed AgI/Bi4O5I2 composites. Based on the synergetic characterizations by in situ X-ray photoelectron spectroscopy, band edge measurements, as well as reactive oxygen species (ROS) detections, the S-scheme photocatalytic mechanism is proved. This work provides a valuable reference for developing efficient and stable S-scheme AgI/Bi4O5I2 photocatalyst for TCH removal.

Natural coal gangue activated persulfate for tetracycline hydrochloride degradation: Mechanisms, theoretical calculations, and comparative study

The development of catalysts with low-cost and high-efficiency for advanced oxidation process is the key issue to remove organic pollutants. In this work, natural coal gangue (CG) was used to activate potassium monopersulfate (PMS) for the removal of tetracycline hydrochloride (TC). For comparison, sodium persulfate (PS), potassium persulfate (PDS), and hydrogen peroxide (H2O2) were also activated by CG to remove TC. The active species in the TC degradation processes in PMS/CG, PS/CG, PDS/CG, and H2O2/CG systems were investigated by capture experiments and electron spin resonance (ESR) tests. DFT calculation indicated that PMS was more easily adsorbed by CG in comparison with PS, PDS, and H2O2. In addition, Fukui function was adopted to determine how electrophilic, nucleophilic and free-radical attacks occurred on sites of TC molecules in detail. Mechanism investigation showed that the surface-bonded and structural hydroxyl groups of natural CG were favorable for the adsorption of PMS molecules onto the CG surface and thus facilitated the generation of active species, which were crucial in the TC degradation process. This paper sheds new light for natural minerals or solid wastes to participate in advanced oxidation process (AOPs) for wastewater treatment.

Construction of plum-branch-like BiOI/NH2-MIL-68(In) Z-scheme heterojunctions for removal of tetracycline hydrochloride from wastewater via synergistic adsorption-photocatalysis process

The synergistic adsorption-photocatalysis process has been considered as a novel, green and effective way in the field of environmental remediation, in which adsorption would facilitate the photocatalysis process by strengthening the link between the contaminant and the catalyst. In this paper, a series of Z-scheme heterojunction adsorption photocatalysts of BiOI/NH2-MIL-68(In) with plum-branch-like morphology were designed and constructed. The adsorption process on BiOI/NH2-MIL-68(In) is heterogeneous and multilayer, and the as-formed chemical adsorption is mainly attributed to the effects of electrostatic attraction, π-π conjugation and hydrogen bonding. Such produced high adsorption capacity would be conducive to the further photocatalytic degradation of tetracycline hydrochloride (TC). The removal efficiency on 1.5-BiOI/NML reaches 90.04 % after an hour dark reaction following 30 min visible light irradiation, which is 5.08 and 8.61 times than that of the original BiOI and NH2-MIL-68(In). The mechanism of TC removal and the possible pathway of photocatalytic degradation are reasonably proposed. This study provides some enlightenment for the design and construction of visible light responsive adsorbents in the field of wastewater treatment.

Preparation of TiO2/Fe-MOF n‒n heterojunction photocatalysts for visible-light degradation of tetracycline hydrochloride

Visible-light-assisted photocatalysis has been recognized as an effective solution to the degradation of various pollutants including antibiotics, pesticides, herbicides, microplastics, and organic dyes. Herein, an n-n heterojunction TiO2/Fe-MOF photocatalyst is reported, designed via solvothermal synthesis route. TiO2/Fe-MOF photocatalyst was characterized by XPS, BET, EIS, EDS, DRS, PL, FTIR, XRD, TEM, SEM and HRTEM techniques. Inspired by XRD, FTIR, XPS, EDS, TEM, SEM, and HRTEM analyses, the successful synthesis of n-n heterojunction TiO2/Fe-MOF photocatalysts was proved. The migration efficiency of the light-induced electron-hole pairs was confirmed by the PL and EIS tests. TiO2/Fe-MOF exhibited a significant performance for tetracycline hydrochloride (TC) removal under visible light irradiation. TC removal efficiency for TiO2/Fe-MOF (15%) nanocomposite reached 97% within 240 min, ca. 11 times higher than pure TiO2. The photocatalytic enhancement of TiO2/Fe-MOF could be attributed to the broadening the light response range, forming an n-n junction between Fe-MOF and TiO2 components, suppressing charge recombination. Based on recycling experiments, TiO2/Fe-MOF had a good potential to be used in consecutive TC degradation tests.

Synthesis of Carnation-Like ZnO for Photocatalytic Degradation of Antibiotics, Including Tetracycline Hydrochloride

ZnO has been known to be an excellent photocatalyst and production of suitable morphology by cheap methods to increase catalytic efficiency is important in practical applications. In this study, a fast precipitation method was used to produce the carnation-like morphology to improve the performance of ZnO in the removal of tetracycline hydrochloride (TCH). The precursor of zinc nitrate, precipitation agents of sodium hydroxide, and trisodium were used to control the morphology of ZnO. The characterization of as-prepared material was confirmed by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, diffuse reflectance ultraviolet-visible, and N2 adsorption/desorption isotherms. As a result, the ZnO appeared with a regular and uniform three-dimensional carnation-like morphology and consisted of numerous nanosheets with a thickness of 0.013 μm. The average size of the ZnO flowers was 5 μm. In addition, the plausible formation mechanism of nanoflower with time was proposed. The effects of reaction conditions on the catalytic performance of ZnO were thoroughly examined, and its performance was compared with those of other ZnO forms and other materials. As-prepared ZnO showed to efficiently decompose TCH with the decompose efficiency and rate constant of 89.92% and 0.038 min−1, respectively. Moreover, the •O2− and h+ were key active species in the decomposition of the TCH process.

Enhanced solar-induced photocatalytic removal of antibiotics over molecularly reconstituted graphitic carbon nitride

Promoting the photocatalytic performance of graphitic carbon nitride (g–C3N4) for efficient removal of organic contaminants like antibiotics from wastewater has gained much consideration due to its metal-free uniqueness and environmental friendliness. In this work, the photocatalytic activity of g–C3N4 is greatly enhanced via a hydrothermally molecular dissociation and subsequent calcination reconstitution, which endows g–C3N4 with a large specific surface area, rapid separation of photogenerated electron/holes and strong redox ability. The apparent kinetic constant (k) of tetracycline hydrochloride (TCH) for the sample obtained under the optimal preparation conditions (CN–C–12) is 4.5 times that of pristine g–C3N4, companied with a stable cycling photocatalytic activity. The possible degradation pathways and the toxicological evaluation of the intermediates were analyzed by LC-MS and ECOSAR. Superoxide radicals (∙O2–) and singlet oxygen (1O2) are detected to be the primary reactive species in the photocatalytic degradation of TCH. Additionally, the practical application of CN–C–12 for TCH removal in actual sunlight and treatment of domestic printing and dyeing wastewater was also investigated. This work shows a potential application of the molecular reconstituted g–C3N4 in the photo-catalytically environmental purification.

Hollow BiOI/Bi5O7I hierarchical microsphere with S-scheme heterostructure for efficiently removal of tetracycline hydrochloride

The problem of environmental pollution caused by the frequent use of antibiotics has attracted extensive attention. The heterojunction composed of various bismuth oxyiodide (such as BiOI, Bi4O5I2, Bi5O7I, etc.) were widely used in the treatment of antibiotic wastewater. Herein, a hollow BiOI/Bi5O7I hierarchical microsphere was constructed in-situ by annealing BiOI precursors synthesized by the solvothermal method. The phase transition temperature for the formation of heterojunctions has been investigated in detail. The obtained products were characterized by various technologies including transmission electron microscope (TEM), X-ray photon-electron spectroscopy (XPS), and so on. Experimental results suggested that 390-BiOI/Bi5O7I microsphere with hollow structure exhibits the optimal performance and maximum photocurrent response under visible light irradiation. The efficiency for degradation of tetracycline hydrochloride (TH) was up to 83 % in 100 min. The value still maintained at 95 % after the catalyst has been reused for four times. The capture experiment indicates that produced ·O2− played the most important role. But formed h+ and ·OH played a secondary role. The degradation intermediates were analyzed by Liquid Chromatography-Mass Spectrometry (LC-MS). Accordingly, the possible degradation pathways are proposed. An S-scheme based heterostructure photocatalytic mechanism is proposed aiming to explain the enhanced catalytic performance. The BiOI/Bi5O7I heterojunction with exceptional activity and stability is bound to expand applications in the field of water treatment.

Tetracycline hydrochloride degradation by activation of peroxymonosulfate with lanthanum copper Ruddlesden-Popper perovskite oxide: Performance and mechanism

ABO3-type perovskite oxides have been regarded as a kind of potential catalyst for peroxymonosulfate (PMS) activation. But some limitations such as specific pH conditions and coexisting ion interference restrict its practical application. Herein, a lanthanum copper Ruddlesden-Popper perovskite oxide (La2CuO4) was successfully synthesized through the sol-gel process and applied in the activation of PMS. And for the first time the La2CuO4/PMS system was used for tetracycline hydrochloride (TC-HCl) degradation. Results showed that La2CuO4 was a potential PMS activation catalyst in the removal of antibiotics. At optimized condition (0.2 g/L catalysts, 1 mM PMS, pH0 6.9), 96.05% of TC-HCl was removed in 30 min. In experiments of debugging control conditions, over a wide pH range of 3–11, more than 90% of TC-HCl can be removed. In the natural water treatment process, TC-HCl removal rates of about 84.2% and 70.3% were obtained in tap water and River water, respectively. According to the reusability and stability tests and the results of FTIR and XPS analysis, La2CuO4 had high structural and chemical stability. Electron paramagnetic resonance (EPR) suggested that the active species including ·OH, SO4−· and 1O2 were detected in degradation reaction. Finally, reasonable reaction mechanisms and possible degradation pathways of TC-HCl were proposed. These results indicate that La2CuO4 can act as a potential catalyst for PMS activation to degrade TC-HCl in water.

Mechanochemically Synthesized Solid Solutions La1−xCexFeO3+x/2 for Activation of Peroxydisulfate in Catalytical Reaction for Tetracycline Degradation

The synthesis of orthoferrites of the type La1−xCexFeO3+x/2, x = 0.00, 0.01, 0.03, 0.05, and 0.07, by applying a simple and effective mechanochemical transformation from the constituent oxides is presented. Physicochemical methods such as powder X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–Vis spectroscopy, and Brunauer–Emmett–Teller (BET) adsorption were applied to gain information about the effect of Ce4+ content on the structural, textural, and optical properties of the samples. The catalytic activity of the samples for water decontamination was determined in a photo-Fenton-like activation of persulfate for removal of tetracycline hydrochloride as model pollutant. The presence of persulfate, PDS, considerably increased the removal efficiency under visible light illumination.

Architecture and active motif engineering of N–CoS2@C yolk–shell nanoreactor for boosted tetracycline removal via peroxymonosulfate activation: Performance, mechanism and destruction pathways

Rational construction of yolk-shell architecture with regulated binding configuration is crucially important but challengeable for antibiotic degradation via peroxymonosulfate (PMS) activation. In this study, we report the utilization of yolk-shell hollow architecture consisted of nitrogen-doped cobalt pyrite integrated carbon spheres (N–CoS2@C) as PMS activator to boost tetracycline hydrochloride (TCH) degradation. The creation of yolk-shell hollow structure and nitrogen-regulated active site engineering of CoS2 endow the resulted N–CoS2@C nanoreactor with high activity for PMS activating toward TCH degradation. Intriguingly, the N–CoS2@C nanoreactor exhibits an optimal degradation performance with a rate constant of 0.194 min−1 toward TCH via PMS activation. The 1O2 and SO4•− species are demonstrated as the dominant active substances for TCH degradation through quenching experiments and electron spin resonance characterization. The possible degradation mechanism, intermediates and degradation pathways for TCH removal over the N–CoS2@C/PMS nanoreactor are unveiled. Graphitic N, sp2−hybrid carbon, oxygenated group (C–OH) and Co species are verified as the possible catalytic sites of N–CoS2@C for PMS activation toward TCH removal. This study offers a unique strategy to engineer sulfides as highly efficient and promising PMS activators for antibiotic degradation.

Powder-precursor integrated 3D-printed TiO2 photocatalyst and adsorption-degradation synergy effect

The practicability of nano-powder photocatalyst is limited by the difficulty of its recovery. 3D monolithic TiO2 photocatalyst (MTP) was printed by direct ink writing (DIW) using TiO2 nanoparticles as solutes of tetrabutyl titanate precursor to configure printing slurry to achieve integrated regulation of microscopic and macroscopic pore structure. The SEM verified that the surfaces of skeleton-TiO2 particles were uniformly covered by the TiO2 nanoparticles derived from calcining gel. And a highly connected hierarchical pore structure was formed by the skeleton-TiO2 particles and the designed 3D printing macroscopic pores, which laid the foundation for rapid capture and efficient in situ degradation of antibiotics. The nano TiO2 powders prepared by calcined gel have narrow band gap width, which is easier to generate electrons and holes and have low recombination rate. Therefore, the core-shell structure constructed by nanoparticles derived from gel and commercial TiO2 can effectively optimize the photocatalytic performance of MTP. The removal of tetracycline hydrochloride (TCCH) in water by MTP was used to verify the application effect of macro structure in practice, and the synergistic effect of adsorption and degradation kinetics was summarized. The dynamic adsorption effect of MTP reached 97.44 % at pH 7 for 5 h. Under simulated sunlight, MTP exhibited a synergistic adsorption-degradation effect, reaching equilibrium at 210 min. The cycle test shows that the removal rate of TCCH by MTP remains 91 % after 4 cycles. This strategy provides a good reference for the assembly of nanosemiconductor materials into environmentally friendly 3D structured systems.

Meta-kaolinite/LaFeCoO3 microsphere catalyst for photocatalytic persulfate activation: Enhanced removal of tetracycline hydrochloride

In this study, modified intercalated kaolinite was uniformly anchored on the surface of monodisperse LaFe0.5Co0.5O3 microspheres through a two-step approach. The tetracycline hydrochloride (TCH) removal efficiency of the samples was evaluated under a combined visible light/peroxodisulfate (Vis/PS) system. The meta-kaolinite/LaFe0.5Co0.5O3 (MK/LFCO) composite afforded enhanced photocatalytic activation of PS because of the rapid electron transfer, increased number of surface reactive sites, and enhanced specific surface area and pore volume caused by LFCO and MK. Density functional theory calculations revealed that Co doping could alter the charge distribution and accelerate localized charge separation. Additionally, the photogenerated carriers could be captured by the O vacancies and Co/Fe active sites, facilitating the separation of photogenerated carrier separation and FeIII/FeII interconversion. Based on electron paramagnetic resonance spectroscopy and radical quenching experiments indicated that SO4•− was the key radical species under the Vis/PS system. This work comprehensively reveals the mechanism of MK/LFCO-catalyzed TCH degradation, while providing novel insights regarding kaolinite-based catalysts for wastewater treatment under Vis/PS systems.

Reactive Ceramic Membrane for Efficient Micropollutant Purification with High Flux by LED Visible-Light Photocatalysis: Device Level Attempts

Micropollutants (MPs) are widely occurring in surface water all over the world with extremely low concentrations, and their treatment requires high energy consumption and efficiency. In this study, a large-sized planar photocatalytic reactive ceramic membrane (PRCM) was prepared using the facile dip-coating method with nitrogen-doped TiO2 (N-TiO2-CM) for the purification of tetracycline hydrochloride (TC) as a model MP. The N-TiO2 nanoparticles and the as-prepared N-TiO2-CM were characterized by SEM/EDS, TEM, XPS, UV–Vis DRS, and FT-IR. A fixed bed reactor integrated N-TiO2-CM, and visible LED light was fabricated for the new PRCM water treatment system for the removal of TC with a comprehensive consideration of the degradation rate and permeate flux. The SEM/EDS results indicated that the N-TiO2 was uniformly and tightly loaded onto the flat CM, and the pure water flux could reach over 2000 L/(m2 × h) under a trans-membrane pressure (TMP) of −92 kPa. The fixed bed PRCM water treatment system is extremely suited for MP purification, and the removal efficiency of TC was as high as 92% with 270 min even though its initial concentration was as low as 20 mg/L. The degradation rate and permeate flux of N-TiO2-CM was 2.57 and 2.30 times as high as that of the CM, indicating its good self-cleaning characteristics. The quenching experiments illustrated that the reactive radicals involved in the PRCM process, •OH and •O2−, were responsible for TC degradation. This research also provides a utilization proposal for a scale-up N-TiO2-CM system for water and wastewater treatment.

Perylene diimide/iron phthalocyanine Z-scheme heterojunction with strong interfacial charge transfer through π-π interaction: Efficient photocatalytic degradation of tetracycline hydrochloride

The development of an all-organic Z-scheme heterojunction photocatalyst with the matched band structure, efficient electron transfer and excellent photocatalytic performance is valuable for a sustainable future. A novel perylene diimide/phthalocyanine iron (PDI/FePc) heterojunctions with strong π-π interaction were synthesized by a self-assembled method, which exhibited strong visible-light-driven photocatalytic degradation activities of tetracycline hydrochloride (TC). The TC removal rate over PDI/FePc was achieved three times and 87.5 times higher than that of PDI and FePc. PDI/FePc (131.1 mv·dec−1) presented a lower Taffel slope than that of PDI (228.6 mv·dec−1) for the oxidation. This may be due to the strong π-π interactions between PDI and FePc, which can reduce the layer spacing of the supramolecular structure and facilitate the separation and transfer of photogenerated carriers in the built-in electric field. In addition, radical quenching tests revealed that superoxide radicals (•O2−) acted as a dominant role in photocatalytic oxidation. An increscent specific surface area of PDI decorated by FePc also gave the rapid pathway for charge transfer and enhanced the adsorption ability. This provides a new idea for the formation of heterojunction to improve the photocatalytic activity of organic supramolecular materials.

Insight into the improved photocatalytic removal of tetracycline hydrochloride by constructing cobalt doping in 2D/2D (BiO)2CO3/BiOCl type-II heterojunctions

Element doping coupled with heterojunction construction and morphology control is an efficient way to improve the properties of photocatalytic materials. Here, a thiourea-modified 2D/2D cobalt-doped (BiO)2CO3/BiOCl heterojunction photocatalyst (denoted as Co-(BC/BL)Tu) was constructed by a simple one-pot hydrothermal method. The photocatalytic property of Co-(BC/BL)Tu product was evaluated by the photocatalytic degradation of tetracycline hydrochloride (TC-HCl). Compared with the pure (BiO)2CO3 sample, the as-prepared Co-(BC/BL)Tu product displayed outstanding visible-light-driven photodegradation property. The photodegradation rate constant k value of the Co-(BC/BL)Tu product was 5.2 times higher than that of pure (BiO)2CO3, which was the result of the synergistic effect of the 2D/2D structure, cobalt doping and type-Ⅱ heterostructures. It could simultaneously boost the visible light harvesting of the photocatalytic system as well as charge separation. This study provides a facile and promising strategy for constructing a high-effective photocatalytic system by combining morphology control engineering, doping engineering, and heterostructure engineering.