Photocatalytic Degradation Process Research Articles

Electrospinning preparation of TPU/TiO2/PANI fiber membrane with enhanced dye degradation and photocatalytic Cr(VI) reduction

The efficient elimination of toxic dye and Cr(VI) from wastewater by photocatalysis is still a challenge due to the unsatisfactory photocatalytic efficiency and difficult separation of the photocatalyst. Herein, the thermoplastic polyurethane (TPU) fiber membrane was prepared by electrospinning and then titanium dioxide (TiO2) nanoparticles were loaded on the fiber membrane by ultrasonic-assisted method, followed by in-situ polymerizations of polyaniline (PANI) on the surface of the membrane. The synergistic effect of TiO2 and PANI results in faster charge migration and more efficient separation of photogenerated charge carriers. Photocatalytic experiments revealed that TPU/TiO2/PANI fiber membranes were highly efficient for dye degradation and Cr(VI) reduction under visible light irradiation. 99.7 % of Congo red was degraded by TPU/TiO2/PANI membrane within 30 min, and the reaction rate reached 0.2 min−1. The Cr(VI) reduction efficiency was up to 99.0 % within 25 min with a reaction rate of 0.128 min−1. Additionally, the TPU/TiO2/PANI membrane exhibited a low loss in catalytic activity even after recycling 10 times, suggesting superior recycling stability compared to TPU/TiO2 membrane. The result of the electron spin resonance (ESR) experiment showed that superoxide radicals (-O2-) and hydroxyl radicals (-OH-) were involved in the photocatalytic degradation process. The prepared TPU/TiO2/PANI fiber membrane combined with excellent photocatalytic capacity, good stability and easy recovery makes it a good candidate for removing dye and Cr(VI) from wastewater.

Sustainable and energy-efficient photocatalytic degradation of textile dye assisted by ecofriendly synthesized silver nanoparticles

In this study, we have touched on two goals of sustainable development, namely, the provision of clean water and sanitation and clean energy at acceptable prices, hoping for good health for all ages. A green economical method was used to prepare silver nanoparticles from chitosan biopolymer. AgNPs were fully characterized using UV–Vis, FTIR, XRD, HR-TEM, and EDX analysis. Different concentrations (0.02–0.18 g/L) of the nanoparticles were integrated into a mixture of heterogeneous nano photocatalysts TiO2 and ZnO (1:1 weight ratio) under UV irradiation for the photocatalytic degradation of Acid Red 37 textile dye to obtain clean water. The kinetic description of the performed photocatalytic process was presented assuming a pseudo-first-order reaction. The data revealed that increasing the concentration of AgNPs in the catalytic mixture showed a high apparent rate constant (kapp) accompanied by an increase in the apparent quantum yield (%Qapp), followed by dye destruction after a very short time (t0.5 = 3 min). Since the photocatalytic degradation process consumes electrical energy, the electrical energy per order (EE/O) was calculated, showing a low value of 20 kWh/m3/order, using 0.18 g/L AgNPs, indicating that the elicited photocatalytic degradation method is a sustainable one for the mineralization of the targeted dye.

In-Depth Insight into the Ag/CNQDs/g-C3N4 Photocatalytic Degradation of Typical Antibiotics: Influence Factor, Mechanism and Toxicity Evaluation of Intermediates.

In this paper, the photocatalytic degradation efficiency of typical antibiotics (norfloxacin (NOR), sulfamethoxazole (SMX) and tetracycline hydrochloride (TCH)) by Ag/CNQDs/g-C3N4 under visible light irradiation was studied. Various strategies were applied to characterize the morphology, structure and photochemical properties of the Ag/CNQDs/g-C3N4 composites. The superior photocatalytic activity of Ag/CNQDs/g-C3N4 was attributed to the wide light response range and the enhancement of interfacial charge transfer. At the same time, the effect of the influence factors (pH, Humic acid (HA) and coexisting ions) on the antibiotics degradation were also investigated. Furthermore, the electron spin resonance (ESR) technology, free radical quenching experiments, LC/MS and DFT theoretical calculations were applied to predict and identify the active groups and intermediates during the photocatalytic degradation process. In addition, Ag/CNQDs/g-C3N4 exhibited the obvious antibacterial effect to Escherichia coli due to the addition of Ag NPs. This study develops a new way for the removal of emerging antibiotic pollution from wastewaters.

Visible-light-driven photocatalytic degradation of tetracycline hydrochloride by Z-scheme Ag3PO4/1T@2H-MoS2 heterojunction: Degradation mechanism, toxicity assessment, and potential applications

Residual antibiotics in wastewater threaten living organisms and the ecosystem, while the photocatalytic process is recognized as one of the most eco-friendly and promising technologies for the treatment of antibiotic wastewater. In this study, a novel Z-scheme Ag3PO4/1T@2H-MoS2 heterojunction was synthesized, characterized, and used for the visible-light-driven photocatalytic degradation of tetracycline hydrochloride (TCH). It was found that Ag3PO4/1T@2H-MoS2 dosage and coexisting anions had significant effects on the degradation efficiency, which could reach up to 98.9 % within 10 min under the optimal condition. Combing experiments and theoretical calculations, the degradation pathway and mechanism were thoroughly investigated. The excellent photocatalytic property of Ag3PO4/1T@2H-MoS2 was achieved attributed to the Z-scheme heterojunction structure, which remarkably inhibited the recombination of photoinduced electrons and holes. The potential toxicity and mutagenicity for TCH and generated intermediates were evaluated, which revealed the ecological toxicity of antibiotic wastewater was reduced effectively during the photocatalytic degradation process.

Synergistically enhanced photocatalytic degradation of tetracycline hydrochloride by Z-scheme heterojunction MT-BiVO4 microsphere/P-doped g-C3N4 nanosheet composite

The elimination of tetracycline hydrochloride (TC-HCl) from water has attracted extensive research attention. This study hydrothermally synthesized composite photocatalysts composed of BiVO4 microspheres containing coexisting phases of monoclinic scheelite (M-BiVO4) and tetragonal zircon (T-BiVO4), i.e., MT-BiVO4, loaded onto P-doped g-C3N4 nanosheets (PCNS). Furthermore, their morphology, structure, and photoelectrochemical properties were comprehensively characterized, and the performance and stability of photocatalytic degradation of TC-HCl were examined. Additionally, the effects of humic acid (HA), coexisting anions/cations, and actual water samples on the degradation efficiency of TC-HCl were investigated, and the degradation mechanism and pathways were examined. The findings indicated that the percentage of M-BiVO4 in MT-BiVO4 considerably influences the photocatalytic activity of the composite catalyst. Furthermore, the excellent photocatalytic performance of 5% BVO/PCNS was attributed to the synergistic effects of P-doping the modified g-C3N4, MT-BiVO4 isotype heterojunction effects, and the Z-scheme heterojunction constructed from MT-BiVO4 and PCNS, which can enhance the absorption range of the visible light and accelerate the transfer and separation of charge carriers between catalysts. The free radical capture experiments and electron spin resonance tests indicated that holes and O2- were the dominant active species in the photocatalytic degradation process. With high reusability and stability, the 5% BVO/PCNS composite has great potential for practical wastewater treatment applications. This study offers a new approach for preparing photocatalysts synergized by isotype and Z-scheme heterojunctions.

Adsorption and photocatalytic degradation process of oxytetracycline using mesoporous Fe-TiO2 based on high-resolution mass spectrometry

In this study, the adsorption and photocatalytic degradation of oxytetracycline (OTC) were systematically investigated using different metal-doped anatase-phase mesoporous TiO2 nanocatalysts (M−TiO2, M = Fe, Co, Ni, Cr). The results showed that doping with different metals had a significant effect on the ability of TiO2 to adsorb and degrade OTC. Comparing the photoelectric properties of four photocatalysts (Fe-TiO2, Co-TiO2, Ni-TiO2 and Cr-TiO2), it was observed that the mutual synergy between the separation ability of the photogenerated carriers and the adsorption ability of pollutants was the fundamental reason for the excellent photocatalytic performance of Fe-TiO2. The relative intensities of the high-resolution mass spectrometry (HRMS) peaks were used to track and analyse the degradation products of pollutants at different adsorption or light-irradiation times during the photocatalytic process. The ability of the pollutants to undergo dark-state adsorption significantly influenced their degradation paths and products. The possible mechanism of the photocatalytic decomposition of pollutants using Fe-TiO2 along different paths was proposed according to the Fukui function calculation and MS results. To the best of our knowledge, this is the first time that quantitative HRMS results have been used to assess the degradation pathways of pollutants.

Orange peel-derived Cu2O/RGO nanocomposite: Mesoporous binary system for degradation of doxycycline in water.

The online version contains supplementary material available at 10.1007/s10668-022-02895-2.

Removal of ceftriaxone sodium antibiotic from pharmaceutical wastewater using an activated carbon based TiO2 composite: Adsorption and photocatalytic degradation evaluation

The water pollution becomes a serious concern for the sustainability of ecosystems due to the existence of pharmaceutical products (ceftriaxone (CEF) antibiotic). Even in low concentration of CEF has lethal effects on ecosystem and human health. To remove CEF, TiO2 is considered as an effective and efficient nanoparticles, however its performance is reduced due to wider energy gap and rapid recombination of charge carriers. In this study, activated carbon based TiO2 (ACT-X) heterogeneous nanocomposites were synthesized to improve the intrinsic properties of TiO2 and their adsorption-photocatalytic performance for the removal of CEF. The characterization results revealed that ACT-X composites have slower recombination of charge carriers, lower energy band gap (3.05 eV), and better light absorption under visible region of light. From ACT-X composites, the ACT-4 photocatalyst has achieved highest photocatalytic degradation (99.6%) and COD removal up (99.2%). The results of radical scavengers showed that photocatalytic degradation of CEF is mainly occurred due to superoxide and hydroxyl radicals. Meanwhile, the reusability of ACT-4 up to five cycles shows more than 80% photocatalytic degradation, which make the process more economical. The highest experimental adsorption capacity is achieved up to 844.8 mg g−1 using ACT-4. The favorable and multilayer heterogeneous adsorption is carried out according to the well-fitted data with pseudo-second-order and Freundlich models, respectively. These results indicate that the carbon-based TiO2 composites can be used as a green, stable, efficient, effective, reusable, renewable, and sustainable photocatalyst to eliminate the pharmaceutical pollutants (antibiotics) via adsorption and photocatalytic degradation processes.

The preparation of Ag@AgCl photocatalytic material based on the photocatalysis material CA+ and degradation of tetracycline

In this paper, the photocatalysis material CA+, which uses calcium alginate as carrier and cetyltrimethylammonium bromide as surfactant, was studied. The morphology and structure of the prepared CA+ were characterised by SEM, TEM, FT-IR and Raman spectroscopy. The surface electrical properties and stability of the catalytic materials were evaluated by Zeta potential and cycling performance measurements, and the data were analyzed and processed according to the principle of degradation kinetics. The results show that Ag@AgCl Nanoparticles are distributed on the cross-linked structure of CA in the form of clusters. The prepared CA+ photocatalyst material has good adsorption performance and photocatalytic activity for tetracycline (TC). Temperature has a significant effect on the degradation of TC by photocatalytic materials. The photocatalytic degradation rate is the highest at 40 °C, and the photocatalytic reaction rate was 0.08276 min−1. The photocatalytic degradation process at different temperatures conforms to the quasi first-order reaction kinetics. Adding a certain amount of H2O2 can produce more active species O2 −. The photocatalytic material has the advantages of good stability, short photocatalytic degradation time, high catalytic efficiency, and can be used for the degradation of actual tetracycline polluted wastewater.

Synthesis of Graphene oxide/Porphyrin Nanocomposite for Photocatalytic Degradation of Crystal Violet Dye

AbstractA novel nanocomposite was synthesized by covalent functionalization of graphene oxide (GO) with 5,10,15,20‐tetrakis(4‐hydroxyphenyl)porphyrinatoiron (III) chloride (Fe−THPP) via an ester linkage. The synthesized nanocomposite was characterized by various techniques such as XPS, Raman spectroscopy, BET, IR, UV‐Visible, TGA, SEM, and EDX. The synthesized nanocomposite exhibited appreciable interaction with crystal violet (CV) dye with a detection limit of 2.6×10−6 μg/mL and binding constant of 35.93×103 ppm−1 which ensured the high concentration of CV dye on the surface of synthesized photocatalyst. The nanocomposite was effectively utilized in the photo‐degradation of CV dye under visible light irradiation. The photo‐degradation efficiency was remarkably high (93.45 %) with a low catalytic dosage of 0.4 mg/L within 80 minutes. The nanocomposite exhibited good stability and reusability and thereby can be used in the photocatalytic degradation processes to treat wastewater.

Magnetically retrievable Fe3O4@SiO2@ZnO piezo-photocatalyst: Synthesis and multiple catalytic properties

The piezo-/photocatalytic effects of ZnO have been in the limelight because of their great potential in environmental remediation and energy conversion. However, the poor recyclability of the suspended catalysts can cause inevitable secondary pollution, which is one of the major issues that limit the practical application of these materials. To address this problem, a magnetically retrievable Fe3O4@SiO2@ZnO nanocomposite was designed and successfully synthesized by multi-step reactions. The ZnO nanorods were vertically grown on the surface of the magnetic Fe3O4@SiO2 microspheres, while SiO2 served as an insulator to protect the inner core and to inhibit charge transfer across the core/shell interface. The Fe3O4@SiO2@ZnO nanocomposite can be easily collected and separated by using a magnetic field. Along with the good recyclability, the material also exhibited high efficiencies in piezocatalytic, photocatalytic and piezo-photocatalytic dye degradation processes. The rate constant of piezo-photocatalysis reached 95.9 × 10−3 min−1, which was 2.2 and 6.1 times that of the individual piezocatalysis and photocatalysis, respectively. The present result confirmed the existence of a synergetic effect between piezo- and photocatalytic processes. Hereby, we demonstrated that incorporation of a magnetic carrier is a feasible strategy to achieve retrievable and highly efficient piezo-/photocatalyst.

Comparative Photocatalytic Activity and Total Organic Carbon Removal Efficiency of TiO2 And ZnO for Reactive Black 5 Photodegradation

AbstractThe photocatalytic performance of TiO2 and ZnO was comparatively studied for photocatalytic degradation of reactive black 5 (RB5) under artificial UVC irradiation. The effect of initial solution pH, catalyst concentration, initial RB5 concentration, purging oxygen rate, stirring rate, and process temperature on the degradation process by TiO2 and ZnO was investigated. In addition, total organic carbon (TOC) analysis has been employed for each parameter to detect the presence of organic intermediates and the photodegradation performance of catalysts simultaneously with the photocatalytic degradation process. The RB5 photodegradation was more rapid in the aqueous medium by TiO2 under UVC irradiation compared to the catalysis by ZnO. On the other hand, the slower photocatalysis by ZnO resulted in generating more organic intermediates. The structural and morphological analyses of photocatalysts TiO2 and ZnO were performed using XRD and FE‐SEM techniques. The UV‐vis spectroscopy measurements supported that the TiO2 demonstrated evidently better photocatalytic activity than ZnO for RB5 degradation.

Construction of a Bi2WO6/BiVO4 photocatalytic system for efficient visible light degradation of tetracycline drugs.

A Bi2WO6/BiVO4 composite photocatalytic material was synthesized by the hydrothermal method, and achieved the effective degradation of oxytetracycline (OTC) and tetracycline (TC) under visible light. The compositions, structures, chemical states and optoelectronic properties of Bi2WO6, BiVO4 and Bi2WO6/BiVO4 composites were characterized by systematic characterization. The results show that the existence of the heterojunction interface facilitates the separation of photogenerated carriers. Compared with the pure catalyst of Bi2WO6 and BiVO4, the Bi2WO6/BiVO4 composite material significantly improves the degradation efficiency of OTC and TC. The degradation rate is 6.22 and 3.02 times higher than that of Bi2WO6 and BiVO4, respectively. Through the free radical quenching experiments, it is known that photogenerated holes (h+) and superoxide anion free radicals (·O2 -) are the main active substances in the degradation of OTC. By analyzing the process of photocatalytic degradation of OTC, there are mainly six intermediates during the process. Their possible degradation pathways are also inferred in this paper.

Insights into the formation of environmentally persistent free radicals during photocatalytic degradation processes of ceftriaxone sodium by ZnO/ZnIn2S4

At present, the researches on photocatalysis were mainly focused on the design, improvement and development of catalysts, and less attention was paid to the existing characteristics of environmentally persistent free radicals (EPFRs) during the process of photocatalytic oxidation. In this study, A flower-like Z-type heterojunction ZnO/ZnIn2S4 (ZnO/ZIS) and typical antibiotic ceftriaxone sodium (CS) were taken as study objects, concentrating on the generation characteristics of EPFRs during the degradation of CS by ZnO/ZIS, and clarifying the degradation mechanism of CS in which EPFRs participated. The results showed that the degradation efficiency of 10 mg/L CS by 0.40 g/L ZnO/ZIS reached 85.3% in 150 min under the irradiation of 500 W xenon lamp. It was clear that ·O2− and h+ play major roles in CS degradation by ZnO/ZIS under visible light, and ·OH plays an auxiliary role. Furthermore, the formation mechanism of EPFRs during photocatalytic degradation processes of CS by ZnO/ZIS were first investigated thoroughly via experimental analysis and density functional theory (DFT) calculations. The concentration level of EPFRs centered on oxygen atoms is 1011 spin/mm3, which were generated in the process of degradation of CS by ZnO/ZIS under visible light. The production of EPFRs chiefly includes two procedures: chemical adsorption and transfer of electrons. The adsorption energy of precursor P8 on ZnIn2S4 side is −1.91 eV, the electrons transferred from precursor P8 and P11 to ZnO/ZnIn2S4 heterojunction. Surprisingly, EPFRs have little negative effects on the degradation process of CS by ZnO/ZIS. The study was not only a key field in the development of photocatalysis technology, but also a new way to study the removal mechanism of antibiotics.

Physicochemical and Photocatalytic Properties of 3D-Printed TiO2/Chitin/Cellulose Composite with Ordered Porous Structures.

In this study, we printed three-dimensional (3D) titanium dioxide (TiO2)/chitin/cellulose composite photocatalysts with ordered interconnected porous structures. Chitin microparticles were mixed with cellulose in the N-methylmorpholine-N-oxide (NMMO) solution to prepare the printing "ink". TiO2 nanoparticles were embedded on the chitin/cellulose composite in the NMMO removal process by water before the freeze-drying process to build the 3D cellulosic photocatalysts with well-defined porous structures. The 3D-printed TiO2/chitin/cellulose composites were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Disperse Spectroscopy (EDS). The XRD and FTIR analyses showed that chitin had an interference effect on the crystal regeneration of cellulose and resulted in a large amount of amorphous phase. The SEM images show that the printed cellulosic strands had a hollow structure, and the EDS analysis showed that TiO2 nanoparticles were embedded on the chitin/cellulose composite surfaces. In the photocatalytic degradation process of methylene blue (MB) dye in an aqueous solution, the TiO2/chitin/cellulose 3D composite photocatalysts demonstrated efficient MB degradation activities with excellent reusability and stability, in which the chitin content performed the function of adjusting the MB degradation efficiency.

Photocatalytic pathway toward real time control of tetracycline from industrial wastewater mediated by hetero-structure CuFe2O4-SnS2

Finding a more effective, long-lasting method to remove antibiotics from wastewater has become more important due to the growth of multi-resistant bacteria by the wide spread of antibiotics. Amidst, photocatalytic degradation process is vital in elimination of contaminants of emerging concern. In this work, CuFe2O4 (CF) coupled with SnS2 (SS), for the first time, was systematically synthesized (CFSS) and the photocatalytic performances were investigated by the photodegradation of tetracycline (TC) under irradiation. The physicochemical features of the nano-photocatalyst were characterized using various spectroscopic and microscopic techniques. The as-developed CFSS (1:2) (k – 0.042 min−1) exhibited exceptional ability towards visible light- mediated TC degradation with an efficiency (η) of almost 98%, which was 6.8 and 11.99 times greater than the pristine CF and SS. The photocatalytic ability of CFSS was further explored by employing the catalyst in real time control of TC from pharmaceutical plant effluent, with degradation efficiency (η) of 87.4%. CFSS has the desirable qualities of an ideal photocatalyst including affordability, improved mineralization efficiency of TC and its recyclability upto six runs (η ∼ 93%). This new nano-photocatalyst with reasonable reusability and stability, aims to offer fresh ideas for improving the photocatalytic decontamination of persistent emerging contaminants.

Enhanced photocatalytic efficiency of TiO2/CdS nanocomposites by manipulating CdS suspension on TiO2 nanoparticles

• TiO 2 /CdS nanocomposites are synthesized at different concentrations of cadmium and sulphur precursors. • The Cd and S precursors ratios affect the size and morphologies of resulting nanocomposites. • Photocatalytic activities are influenced by the precursor ratio. • Stepwise de-ethylation for RhB is observed during visible light photocatalysis. Titanium Dioxide (TiO 2 ) has long been found to be a promising photocatalyst in the ultraviolet region, although it faces several limitations in the visible range. Various attempts for overcoming these shortcomings have shown that TiO 2 nanocomposites offer excellent results for visible area photocatalysis. In the present work, three different samples of TiO 2 /CdS nanocomposites are synthesized using simple and cost-effective hydrothermal method, based on different concentrations of cadmium and sulphur precursors and a comparison is made among them. Characterization techniques like Scanning Electron Microscopy (SEM), Photoluminescence (PL) spectroscopy, UV-visible spectroscopy, X-Ray Diffraction (XRD), Energy Dispersive X-Ray Analysis (EDX) and Fourier Transform Infrared (FTIR) spectroscopy are employed to study morphological, optical, structural, and elemental properties of the as-synthesized nanocomposites. SEM analysis shows that change in concentration of precursors caused morphological changes in the resulting samples. XRD characterization shows that the crystallite size gets modified at different concentrations ranging from approximately 21 nm to 5 nm. As per the UV-Vis spectroscopy, the band gap of TiO 2 /CdS nanocomposites has substantially decreased, making it highly suitable for photocatalytic application in the visible region in comparison to pure TiO 2 . Photocatalytic degradation processes for as-synthesized TiO 2 /CdS nanocomposites are studied for methylene blue (MB) and rhodamine B (RhB) dyes under visible light exposure. Results demonstrate that degradation results for MB dye are better in comparison to RhB dye for all the three synthesized photocatalysts. Futher, it is concluded that TiO 2 /CdS nanocomposite with a 1:1 molar ratio of cadmium and sulphur precursors has the optimum photocatalytic performance for dye degradation.

Enhanced photocatalytic activity of three-dimensional TiO2/reduced graphene oxide aerogel by efficient interfacial charge transfer

TiO2 is one of the most widely used photocatalytic semiconductors. However, the rapid recombination of photogenerated electron-hole pairs severely weakens its photocatalytic activity. Herein, a three-dimensional TiO2/reduced graphene oxide (TiO2-rGO) aerogel with enhanced interfacial charge transfer was synthesized by a facile hydrothermal method, and its photocatalytic degradation of Methylene Blue (MB) and Reactive Red 24 (RR24) dyes was investigated. The photocatalytic results showed that TiO2–rGO aerogel possesses excellent photocatalytic activity, and its photocatalytic degradation rate towards dyes is more than 3.8 times that of pure TiO2 and more than 2.7 times that of TiO2-GO aerogel. Characterization results indicated that the significantly enhanced photocatalytic activity of TiO2-rGO aerogel could be attributed to the enhanced π–conjugated structure of rGO, which can effectively increase interfacial charge transfer and inhibit electron-hole pairs recombination. The mechanism suggested that OH and O2− are the active species in the photocatalytic degradation process. Our findings can provide an important reference for the preparation of high-performance TiO2-based photocatalysts.

Photocatalytic Degradation of 4-tert-butylphenol Using Solar Light Responsive Ag2CO3

In this work, Ag2CO3 was prepared via a solution-based method and was further characterized by XRD, Raman spectroscopy, SEM/EDS analysis, and UV-VIS spectroscopy. SEM results revealed the formation of micro-sized particles with a rectangular shape. The photocatalytic activity of the catalyst was evaluated in the degradation of 4-tert-butylphenol (4-t-BP) under simulated solar light irradiation. The effects of 4-t-BP initial concentration (2.5–10 ppm), catalyst dosage (100–300 mg/L), different types of lamp sources, and water matrix were investigated. Complete 4-t-BP (5 ppm) degradation was achieved after 60 min by Ag2CO3 (200 mg/L). The effect of anions such as CO32−, HCO3−, NO3−, and Cl- in the concentration range of 100–300 mg/L was also studied. CO32− promoted the photocatalytic degradation process, while HCO3− and NO3− exhibited an inhibition effect, which was marked with increasing HCO3− and NO3− concentrations. The presence of Cl− at the concentration of 100 mg/L increased 4-t-BP degradation, but higher concentrations inhibited the photocatalytic reaction. Cyclic experiments showed that the catalyst practically retained its catalytic activity toward 4-t-BP degradation after three successive experimental runs.

Facile preparation and characterization of nanostructured ZnS/PbS heterojunction thin films for enhanced microbial inhibition and photocatalytic degradation

In the present study, we report for the first time the elaboration of n-ZnS/p-PbS heterojunction thin film by spin-coating method and its antimicrobial and photocatalytic activities. The resulting films were characterized using XRD, XPS, FESEM, and EDS. The FESEM results revealed uniform nanostructures films with small spherical shapes and slight variation in diameter. XRD and XPS analysis confirmed the growth of crystalline ZnS and PbS thin films. Photocatalytic degradation of organic dyes was investigated with the elaborated nanocomposite ZnS/PbS under sunlight. The degradation rates of 91.2, 87.1 68.6, and 34.4% were achieved for methylene blue, malachite green, red congo, and methyl orange, respectively. The utilization of heterojunction thin layers assembly enhances the photocatalytic degradation process. The antibacterial and antifungal activities of the coated ZnS/PbS films exhibited considerable behaviour against Staphylococcus aureus, Escherichia coli, and Candida albicans.The present work has not only offered a simple method for the degradation of organic pollutants, but it presents an answer to reduce the rate of microbial contamination.