Bacterial Disinfection Research Articles

Synergistic role of in-situ Zr-doping and cobalt oxide cocatalysts on photocatalytic bacterial inactivation and organic pollutants removal over template-free Fe2O3 nanorods

Herein, we synthesized in-situ Zr-doped Fe2O3 NRs photocatalyst by successive simple hydrothermal and air quenching methods. The synergistic roles of CoOx (1 wt%) and Zr-doping on bacteria inactivation and model organic pollutants over Fe2O3 NRs photocatalyst were studied in detail. Initially, rod-like Zr ((0–8) %)-doped Fe2O3 NRs were produced via a hydrothermal method. CoOx was loaded onto the Zr ((0–8) %)-doped Fe2O3 NRs) surface by a wet impregnation approach. The Zr-doping conditions and CoOx loadings were judiciously optimized, and a highly photoactive CoOx(1 wt%)/Zr(6%)-doped Fe2O3 NRs photocatalyst was developed. The CoOx(1 wt%) loaded Zr(6%)-doped Fe2O3 NRs photocatalyst revealed 99.4% inactivation efficiency compared with (0, 4 and 8)% Zr-doped Fe2O3 NRs, respectively. After CoOx(1 wt%)/Zr(6%)-doped Fe2O3 NRs photocatalyst treatment, Bio-TEM images of bacterial cells showed extensive morphological deviations in cell membranes, compared with the non-treated ones. Additionally, the optimum CoOx(1 wt%)/Zr(6%)-doped Fe2O3 NRs photocatalyst exhibited 99.2% BPA and 98.3% orange II dye degradation after light radiation for 3 h. This work will provide a rapid method for the development of photostable catalyst materials for bacterial disinfection and organic degradation.

Formation and influencing factors of disinfection by-products from bacterial materials in drinking water distribution systems

Abstract In recent years, the contribution of bacterial materials in water distribution systems to DBPs has attracted widespread attention from researchers. The risks and influencing factors of bacterial DBPs are reviewed. Factors affecting the generation of bacterial DBPs include the characteristics of bacterial materials, disinfection process, piping materials, and water quality. Among the major components of biofilms, proteins or amino acids have the greatest risk of DBPs. Among the commonly used disinfection methods, chlorine is more suitable for continuous disinfection of pipe networks than chloramine, but chlorine dioxide may be a better substitute in the future. Pipes with good biological stability, such as polyethylene (PE) pipe, should be encouraged to be used in water supply networks. Periodic removal of biofilms, reduction of organic matter and bromide ion concentrations, and maintenance of high flow rates are effective means to reduce bacterial DBPs. The control, removal and monitoring devices of tube wall biofilm need to be further developed and promoted. In the future, it is urgent to develop new disinfectants that are not easy to react with biomolecules and natural organic matter, and produce fewer or no by-products.

Repetitive Bacterial Disinfection of Respirators by Polydopamine Coating

To solve the current and future mask shortage problems, developing methods of disinfecting respirators is essential, where none of the existing methods have been successfully utilized until recently. Herein, we introduce a novel method of conferring antibacterial activity to the main filtering material (i.e., polypropylene (PP)) of a respirator through sequential polydopamine (PDA) coatings. Two-step dip-coating in dopamine solution, which corresponds to one complete cycle, produces stable PDA films at the interface of the filtering material, which subsequently locally generates H2O2 that can be further transformed into hydroxyl radicals to inactivate pathogens. Specifically, the primary dip-coating creates a scaffold PDA film that acts as a mechanical support, and anchoring dopamine, which substantially produces H2O2, is immobilized to the scaffold PDA during the subsequent secondary dip-coating process. The antibacterial activity was confirmed by bacterial tests using Escherichia coli. In short, the number of colonies after incubation of the polypropylene filter with and without the PDA coating in the bacterial solution was compared. The number of bacteria in the PDA-coated sample (0.54 × 109 CFU/mL·cm2) was significantly reduced compared to that in the original PP sample (0.81 × 109 CFU/mL·cm2), demonstrating a positive relationship with the H2O2 production. Moreover, this antibacterial ability can be maintained by simply utilizing additional PDA coatings, suggesting that the respirators can be recycled. Finally, the in vitro cytotoxicity was confirmed by the CCK-8 assay, which demonstrated that the PDA-coated PP filter is biocompatible. We believe that the newly proposed method for disinfection of respirators may substitute conventional methods and can be used to alleviate the mask shortage problem.

The Bacterial Disinfection of Water Using a Galloping Piezoelectric Wind Energy Harvester

In this study, a method for the bacterial disinfection of drinking water in the water storage systems based on the electric potential generated from a piezoelectric wind energy harvester is presented. First, an efficient galloping piezoelectric wind energy harvester is designed by adding curve- shaped attachments to the bluff body of the harvester. The simulated output voltage of the harvester is validated by performing different sets of experiments on an open environment. Later, the output voltage of the harvester is enhanced, using copper oxide nanowires (CuONWs) grown perpendicular to the surface of the center copper wire. The enhanced electric field is able to disinfect the bacterial water in a 25 min time period. The bacterial removal log efficiency of 2.33 is obtained with a supplied rms voltage of 0.1 V from the harvester. The findings of this study will help to provide alternate means to water treatment that are efficient, reliable, and also free from disinfection by-products.

A conical assembly of six plasma jets for biomedical applications

A conical assembly of six plasma jets arranged in a rectangular pattern for biomedical applications is presented. The conical configuration increases the separation distance between individual tubes within the assembly that reduces interference between individual plasma jets and enables the jets to converge at the output, facilitating more uniform treatment as opposed to plasma jet arrays operated in parallel. Electrical and optical diagnostics of the plasma discharges and measurements of H2O2 and NO2− production in de-ionized water are used to characterize the potential suitability of the device for biomedical applications. Particularly, it was found that the efficiency in H2O2 (an important bacterial disinfection agent) production by the conical assembly of six plasma jets was more than nine-fold higher compared to its single plasma jet counterpart and that this could be achieved at a biocompatible temperature of below 300 K. Therefore, the device may find use in biomedical applications, particularly where larger area treatments are required such as for certain wounds and cancer tumors that can span areas of tens of cm2.

Dual Z-scheme core-shell PANI-CeO2-Fe2O3-NiO heterostructured nanocomposite for dyes remediation under sunlight and bacterial disinfection

Nowadays, environmental pollution due to discharge of organic pollutants from food, textile, and pharmaceutical industries into clean water and development of contagious diseases due to pathogenic organisms provide impetus to material researcher to fabricate novel design for efficient photocatalyst and antimicrobial agents. In this regard, designing a core-shell heterojunction catalyst based on metal oxides is considered an auspicious approach. In present study, combating the problems of singular oxides, core-shell PANI-CeO2-Fe2O3–NiO nanocomposite (PCFN) and CeO2–Fe2O3–NiO nanocomposite (CFN) was synthesized through sol-gel and oxidative polymerization route with cetyletrimethylammonium bromide (CTAB) as surfactant. The XRD, FTIR, and Raman confirmed the formation of nanocomposites with core-shell morphology composed of PANI (shell) and oxides (Core) in PCFN with a particle size of 52 nm (TEM). Surprisingly, PCFN has lower band gap, e−/h+ recombination, and larger charge transfer character than CFN. The decomposition test using MB and MO dyes showed that PCFN degraded 99%, 98%, while CFN degraded only 73% and 54%, respectively, under 50 min sunlight illumination. The reusability was assessed up to 7th cycle for PCFN. The influence of operational parameters (catalyst dose, dye concentration, pH) was tested for PCFN. Further, the antimicrobial action against S. aureus (gram + ve), E. coli (gram -ve) were also tested. The supreme performance of PCFN has been credited to heterostructure dual Z-scheme formation and core-shell morphology supported with PANI, which suppresses the e−/h+ recombination process by promoting their separation. The present finding indicated that the PCFN is a promising modifier for bacterial disinfection and acts as a superb photocatalyst through core-shell formation with PANI support.

Adenosine triphosphate-activated prodrug system for on-demand bacterial inactivation and wound disinfection

The prodrug approach has emerged as a promising solution to combat bacterial resistance and enhance treatment efficacy against bacterial infections. Here, we report an adenosine triphosphate (ATP)-activated prodrug system for on-demand treatment of bacterial infection. The prodrug system benefits from the synergistic action of zeolitic imidazolate framework-8 and polyacrylamide hydrogel microsphere, which simultaneously transports indole-3-acetic acid and horseradish peroxidase in a single carrier while preventing the premature activation of indole-3-acetic acid. The ATP-responsive characteristic of zeolitic imidazolate framework-8 allows the prodrug system to be activated by the ATP secreted by bacteria to generate reactive oxygen species (ROS), displaying exceptional broad-spectrum antimicrobial ability. Upon disruption of the bacterial membrane by ROS, the leaked intracellular ATP from dead bacteria can accelerate the activation of the prodrug system to further enhance antibacterial efficiency. In vivo experiments in a mouse model demonstrates the applicability of the prodrug system for wound disinfection with minimal side effects.

Enhanced sunlight-absorption of Fe2O3 covered by PANI for the photodegradation of organic pollutants and antimicrobial inactivation

• Fabrication of core–shell S-scheme heterojunction Fe 2 O 3 -PANI nanocomposite via simple solution method. • Booted photodegradation of diverse organic pollutants under sunlight. • The enhanced antimicrobial characteristics against various bacterial strains. • The improved charge carrier’s kinetics via S-scheme with PANI. • A promising material against bacterial disinfection and an excellent stable photocatalyst. The current study focused on preparing S-scheme heterojunction Fe 2 O 3 -PANI nanocomposite and pristine Fe 2 O 3 using surfactant-assisted sol–gel and polymerization routes. The structural conformation was assessed through XRD diffractograms that confirmed the Fe 2 O 3 phase in both samples. FTIR data traces the metal–oxygen and carbon-related bonds. PL results showed that the recombination rate is retarded in nanocomposite. TEM images confirmed the covering of PANI over Fe 2 O 3 . EDX mapping showed that Fe, C, N, and O were present in the grown nanocomposite. XPS study revealed the binding energies of constituent atoms. The optical energy bandgap 2.8 and 2.7 eV for Fe 2 O 3 and Fe 2 O 3 -PANI was observed through UV–Vis analysis. The photocatalytic test against methyl blue (MB), eosin yellow (EY), and methyl red (MR) dyes were executed for 50 min under direct sunlight. The Fe 2 O 3 -PANI showed 99.8, 98.5, and 99.6% degradation efficiency against MB, EY, and MR dyes, respectively, which was higher than Fe 2 O 3 . The recyclability assessment confirmed the reusability upto four cycles. The antimicrobial property against E. coli, P-aeruginosa, K-pneumoniae, S. aureus, and P. vulgaris bacterial strains revealed a higher response for Fe 2 O 3 -PANI with the zone of inhibition 30, 31, 31, 30, and 30 nm, respectively. The enhanced performance of Fe 2 O 3 -PANI is being credited to S-scheme heterostructure supported with PANI, which can hinder the recombination process and support electron/hole separation. The results indicated that the as-grown nanocomposite could be a promising candidate against bacterial disinfection and an excellent stable photocatalyst.

Transition metal-doped SnO2 and graphene oxide (GO) supported nanocomposites as efficient photocatalysts and antibacterial agents.

In the present work, pristine and transition metal (TM) (W, Ag, Zn)-doped SnO2 nanocrystals using a facile sol-gel approach were synthesized. The grown products were anchored on graphene oxide (GO) sheets via a simple ultrasonication technique to fabricate binary nanocomposites. The structural, optical, and morphological properties of as-synthesized samples were studied by XRD, FTIR, Raman, EDX, UV-Visible, PL, and FE-SEM. The charge transferability of graphene oxide-based samples was investigated by EIS. The XRD exhibited the TM doping in SnO2 and the development of GO-based nanocomposite. FTIR data evidenced the existence of the metal-oxygen bonds. Raman spectra presented the optical phonon modes of SnO2 and the existence of oxygen vacancy defects. FE-SEM images demonstrated the anchoring of particles on the GO sheet, and EDX further approved the existence of desired dopants. The integration of SnO2 with TM doping remarkably reduced optical bandgap (3.65-3.10eV), which was further decreased (3.10-2.99eV) by making composite with GO. The photodegradation results exhibited that GO-based nanocomposites have the higher potential to degrade synthetic dyes (methyl red (MR), and methyl orange (MO) and SnZnO2/GO have shown superb photocatalytic performance after 80-min sunlight illumination (99.9% MR and 95.0% MO dyes) with the higher rate constant and superior stability up to 6th cycle against MR dye. The grown samples were tested for bacterial disinfection, and SnZnO2/GO sample showed a higher zone of inhibition towards S. aureus and K. pneumoniae bacteria strains. The greater charge transfer rate and lower recombination of charge carriers in GO-based composites were also observed by EIS and PL analysis. Moreover, the present article ascribed that the photocatalytic and antibacterial properties of bare SnO2 could be improved by TM doping and fabricating their composite with GO.

Fabrication of colloidal silver-peptide nanocomposites for bacterial wound healing

Increased antibiotic resistance has become a real healthcare challenge for humanity. Several novel approaches for the formation of nanomaterials have been developed to tackle different bacterial strains and wound disinfection. Short peptide modulated metal nanomaterials have gained attention because of their biocompatibility and ability to reduce metal ions in-situ to form nanoparticles. Here we have used a short peptide conjugate as a reducing and capping agent to make stabilized silver-peptide composite nanoparticles under mild UV light exposure. This photochemical method is one of the green approaches and reduces the toxic effects of chemicals that are often used in traditional synthetic strategies. These composite nanoparticles demonstrated promising activity against Escherichia coli and Staphylococcus aureus at an in-vitro level and have the ability to cure wounds disinfections in-vivo. Furthermore, these composite nanoparticles show excellent biocompatibility, and no side effects were observed in liver enzymes and organs, in a histopathology study. Such a simple strategy of sustainable supramolecular chemistry could help develop novel nanomaterials as potential antibiotic agents of the future.

ZnO nanostructures by hot water treatment for photocatalytic bacterial disinfection

ZnO nanostructures by hot water treatment for photocatalytic bacterial disinfection

Report of the Scientific Committee of the Spanish Agency for Food Safety and Nutrition (AESAN) on the safe use of two aqueous solutions of hydrogen peroxide, acetic acid and peracetic acid as processing aid for bacterial disinfection of plums, cherries and pears washing water at processing plants

Report of the Scientific Committee of the Spanish Agency for Food Safety and Nutrition (AESAN) on the safe use of two aqueous solutions of hydrogen peroxide, acetic acid and peracetic acid as processing aid for bacterial disinfection of plums, cherries and pears washing water at processing plants

2D‐Material‐Integrated Micromachines: Competing Propulsion Strategy and Enhanced Bacterial Disinfection

2Dtransition-metal-dichalcogenidematerials, such as molybdenum disulfide (MoS2 ) have received immense interest owing to their remarkable structure-endowed electronic, catalytic, and mechanical properties for applications in optoelectronics, energy storage, and wearable devices. However, 2D materials have been rarely explored in the field of micro/nanomachines, motors, and robots. Here, MoS2 with anatase TiO2 is successfully integrated into an original one-side-open hollow micromachine, which demonstrates increased light absorption of TiO2 -based micromachines to the visible region and the first observed motion acceleration in response to ionic media. Both experimentation and theoretical analysis suggest the unique type-II bandgap alignment of MoS2 /TiO2 heterojunction that accounts for the observed unique locomotion owing to a competing propulsion mechanism. Furthermore, by leveraging the chemical properties of MoS2 /TiO2 , the micromachines achieve sunlight-powered water disinfection with 99.999%Escherichia colilysed in anhour. This research suggests abundant opportunities offered by 2D materials in the creation of a new class of micro/nanomachines and robots.

Bacterial Disinfection Using Ozone Gas to Extent Spinach’s Shelf Life: The Effect of Dosage, Duration, and Spraying Frequency

Spinach (Amaranthus tricolor) is one type of leafy vegetable famous as a nutrition source in Indonesia. However, it has short shelf life due to bacterial activity, which requires an alternative preservation solution besides drying. Ozone can be used as a disinfectant that is not harmful to humans and has been applied in food and agricultural product preservation. Ozone gas spraying reduces bacterial growth so that quality degradation due to decay can be slowed. In this research, spinach is preserved by spraying ozone gas to the extent of its shelf life. Spinach is ozonated with ozone gas at various dosages of 30.72 mg/hr, 48.60 mg/hr, and 80.16 mg/hr, with the spraying frequency of once, twice, and 3 times for 15 minutes. Ozone gas spraying duration is also variated: 2 minutes, 3 minutes, and 6 minutes. Then, the sample is stored for 7 days to see the change of its characteristic. The best quality during storage is shown by spinach treated with ozonation at a dosage of 48.60 mg/hr; 6 minutes; and the frequency of 3 times. In addition to variations in duration, dosage, and frequency, the same ozone exposure with different combination of duration-frequency and duration-dosage were also observed to evaluate the optimum ozone treatment for preserving spinach, and it was found that longest duration-least frequency and moderate duration-moderate dosage are preferred in maintaining the quality of spinach during storage.

Bacterial Disinfection of Polymethyl Methacrylate (PMMA) Resin Polymer Using Low Level Microwave Irradiation and Denture Cleaning Agent

The aim was to evaluate the disinfection of E. coli, S. aureus and S. mutans cultured on Polymethyl Methacrylate (PMMA) resin polymer using microwave disinfection and sodium perborate (DC). Biofilms of E. coli, S. aureus and S. mutans were cultured on the PMMA denture base for 24, 36, 48 and 96 h. Specimens were subjected to three disinfection protocols, including microwave disinfection in distilled water (MW-DW), sodium perborate (denture cleaning tablet) with distilled water (DC-DW) and a combination of MW-DC-DW for 1 to 5 min. Colony-forming units among the study groups were analyzed using Kruskal–Wallis and Mann–Whitney tests. For E. coli and S. aureus cultured on PMMA, the MW-DC-DW group displayed complete disinfection at 2 min of exposure. However, for both bacteria, the MW-DW disinfection group showed zero CFU at 3 min. DC disinfection for E. coli and S. aureus displayed zero CFU at 5 min of exposure (p ≤ 0.05). For S. mutans, MW-DC-DW and MW-DW displayed zero CFU count at 1 min and 2 min, respectively. In DC-treated samples, CFU were significantly zero at 4 min when compared with the control at each growth time. A combination of MW irradiation with DC (sodium perborate) showed higher disinfection percentage of bacterial species on PMMA polymer denture bases compared to MW and DC alone. PMMA disinfection using DC displayed a lower antimicrobial disinfection percentage than the combined use of MW and DC as well as MW alone at 1 min or 2 min disinfection for E. coli, S. aureus and S. mutans.

Efficacy of Diode Laser Ablation and Low Level Laser Therapy on Healing and Bacterial Load Reduction at Intraoral Biopsy Site.

Statement of the Problem: Healing complications after the conventional surgical biopsy procedure along with bacterial colonization indicates scope for sophisticated techniques. Amalgamation of photo-disinfection along with healing properties of diode laser with practiced biopsy technique can help in dealing with post biopsy complications.Purpose: The present study will analyze the possibility of conjugation of conventional surgical biopsy technique with diode laser regarding its superior properties for achieving better healing and analgesia along with sterilization of the biopsy site.Materials and Method: A randomized control trial was done where punch biopsy procedure was performed for homogenous leukoplakia. Patients were randomly divided into laser group (Test group) and control group. Test group received laser ablation and low level laser therapy (LLLT) on surgical site along with warm saline rinses whereas control group was prescribed with systemic analgesic and antibiotics. Pain on visual analogue scale (VAS), erythema along with the size of defect was evaluated on day 0, 2 and 4. Swabs were collected from the biopsy site and culture was done for evaluation of bacterial load.Results: Highly statistical significant values indicating laser induced analgesia were obtained after analysis for 2nd and 4th day (p= 0.00). Erythema and biopsy defect size evaluation showed significant results for 2nd day (p value 0.023 and 0.004 respectively), which showed absence of erythema and enhancement of healing in test group compared to controls. Statistical significant results were obtained for estimation of bacterial colonization with p value as 0.00, 0.00 for 2nd and 4th day claiming laser supported bacterial disinfection. There was a significant percentage increase on 2nd (p= 0.013) and decrease on 4th post-operative day (p= 0.022).Conclusion: The results encourage the conjugation of conventional incisional punch biopsy with low level lasers to avoid systemic intervention for post biopsy complications.

Titanium-based photocatalytic coatings for bacterial disinfection: The shift from suspended powders to catalytic interfaces

Accessibility to a clean indoor environment is still an important problem in the world. Photocatalysis based on semiconductor materials was proposed as a green solution for contaminated surfaces and domestic areas. This treatment has been considered by many researchers using diverse preparation methods. Titanium dioxide (TiO2) was extensively investigated to treat dyes and microorganisms in wastewater, indoor air and even in wild environments. TiO2 showed divergent efficacy against Gram+ and Gram- bacteria, viruses (DNA-viruses, RNA-viruses, and/or reverse transcribing viruses), algae (unicellular, microalgae…) and free-floating genomic DNA. Today, photocatalysis mediating TiO2 for pollutants removal in real settings is attracting a lot of attention. TiO2 absorbs in the UV spectral region and many techniques were adopted to red shift its absorption to the visible region such as doping, coupling with other semi-conductors or decorating it with plasmonic materials. TiO2 uses started as suspended material in aqueous media. This suspension was fast faced by the difficulty to recover the catalyst after treating water. In the present review, we present the shift from the photocatalytic activity of Ti-based catalysts/photocatalysts for the disinfection of polluted water (TiO2 in suspension) to the implementation of smart indoor surfaces (supported TiO2) presenting self-sterilizing properties. In this review, we present the general context of the water issue as raised by the United Nations 2030-agenda, we show an overview of photocatalytic materials and we try to link the reported photocatalytic mechanisms for the disinfection process. At the end of this review, we stress the advantages of using supported photocatalytic thin films and the interfacial phenomena leading to bacterial killing without sacrificing the catalyst that can be easily reused.

Synergistic effect of total residual oxidants and microplastics on seawater disinfection: An ecotoxicity study

As fishery products are increasingly imported, a treatment system is required to prevent the introduction of invasive pathogens into domestic marine environments. In this study, disinfection efficiency was estimated through ozone treatment of Edwardsiella tarda, Streptococcus mitis, and Vibrio harveyi in seawater. The ecotoxicity of total residual oxidants (TROs) generated during the treatment process was evaluated based on the degree of bioluminescence variation in Aliivibrio fischeri. The interaction with microplastics according to their type and weight was compared in terms of bacterial inactivation and ecotoxicity, along with the level of TROs. In addition, morphological and chemical changes in the ozonated microplastics were analyzed through scanning electron microscopy and Fourier transform infrared spectroscopy. The optimal ozone doses for the inactivation rate of > 99.5% for E. tarda, S. mitis, V. harveyi, and the mixed bacteria were 3, 4, 4, and 5 mg O3/min, while the bioluminescence inhibition rates by TROs were 59.7%, 58.8%, 49.7%, and 54.4%, respectively. Furthermore, there was no considerable difference in bacterial disinfection in the presence of microplastics, but the concentrations of TROs and bioluminescence inhibition rates were slightly lowered owing to the consumption of oxidants.

Synthesis and Characterization of Ag/ZnO Nanoparticles for Bacteria Disinfection in Water.

In this study, two green synthesis routes were used for the synthesis of Ag/ZnO nanoparticles, using cassava starch as a simple and low-cost effective fuel and Aloe vera as a reducing and stabilizing agent. The Ag/ZnO nanoparticles were characterized and used for bacterial disinfection of lake water contaminated with Escherichia coli (E. coli). Characterization indicated the formation of a face-centered cubic structure of metallic silver nanoparticles with no insertion of Ag into the ZnO hexagonal wurtzite structure. Physicochemical and bacteriological analyses described in “Standard Methods for the Examination of Water and Wastewater” were used to evaluate the efficiency of the treatment. In comparison to pure ZnO, the synthesized Ag/ZnO nanoparticles showed high efficiencies against Escherichia coli (E. coli) and general coliforms present in the lake water. These pathogens were absent after treatment using Ag/ZnO nanoparticles. The results indicate that Ag/ZnO nanoparticles synthesized via green chemistry are a promising candidate for the treatment of wastewaters contaminated by bacteria, due to their facile preparation, low-cost synthesis, and disinfection efficiency.

Metal-Doped Graphitic Carbon Nitride Nanomaterials for Photocatalytic Environmental Applications-A Review.

In the current world situation, population and industrial growth have become major problems for energy and environmental concerns. Extremely noxious pollutants such as heavy metal ions, dyes, antibiotics, phenols, and pesticides in water are the main causes behind deprived water quality leading to inadequate access to clean water. In this connection, graphite carbon nitride (GCN or g-C3N4) a nonmetallic polymeric material has been utilized extensively as a visible-light-responsive photocatalyst for a variety of environmental applications. This review focuses on recent developments in the design and photocatalytic applications of metal-doped GCN-based nanomaterials in CO2 photoreduction, water splitting toward hydrogen production, bacterial disinfection, and organic pollutant degradation. Additionally, this review discusses various methods of using GCN-based materials to optimize dye sensitization, metal deposition, ion doping, and their environmental applications.