Enhancing the efficiency of magnetically-driven carbon nitride-based nanocomposites with magnetic nanoflowers for the removal of methylene blue dye at neutral pH

doi:10.21203/rs.3.rs-3449015/v1

Download PDF

Research Article

Enhancing the efficiency of magnetically-driven carbon nitride-based nanocomposites with magnetic nanoflowers for the removal of methylene blue dye at neutral pH

https://doi.org/10.21203/rs.3.rs-3449015/v1

This work is licensed under a CC BY 4.0 License

Journal Publication

published 25 Jan, 2024

Read the published version in Environmental Science and Pollution Research →

You are reading this latest preprint version

The present survey focuses on the elaboration of magnetic nanocomposites by the in-situ incorporation of magnetite (Fe₃O₄) nanoparticles (NPs) with spherical and nanoflower-like) morphologies in graphitic carbon nitride (g-C₃N₄) sheets using two different synthetic routes. Nanomaterials are characterized by TEM, SEM, XRD, FTIR, BET, zetametry, vibrating sample magnetometry, and UV–vis absorption spectroscopy. The decoration of the carbon nitride matrix with the magnetic NPs enhanced optical and textural properties. The influence of the shape of the magnetic NPs on the adsorptive and photocatalytic properties of the nanocomposites under different pH conditions was assessed from batch tests to remove methylene blue (MB) from aqueous solutions. In extreme pH conditions, the nanocomposites exhibited lower or equivalent MB removal capacity compared to the pure g-C₃N₄. However, at neutral medium, the nanocomposite with incorporated Fe₃O₄ nanoflowers showed a significantly higher removal efficiency due to the combination of a high adsorption capacity and a good photocatalytic activity in this pH region. The proposed nanocomposite is a promising alternative to remove cationic dyes from water by magnetic assistance, since no pH adjustment of the polluted effluent is required, reducing costs and environmental impact in the dyeing industry.

carbon nitride

iron oxide

magnetic nanocomposites

nanoflowers

dye removal

The strong resumption of industrial production after the peak of the Covid-19 pandemic has regained the attention of the scientific community, especially concerning the uncontrolled emission of pollutants from different sources, which has been affecting the “green recovery” plan of many countries (Wang and Yang 2021; Manoiu et al. 2022). Particularly in the case of water pollution, the inappropriate discharge of a broad range of contaminants from industry and factory effluents may persist in the ecosystems posing serious threats to the environment and human health (Raza et al. 2023). Innovative decontamination techniques based on nano-engineered materials have been considered as promising alternatives to traditional remediation methods and to prevent the production of waste (Werkneh and Rene 2019). These materials benefit from a large and reactive surface area, which allows the removal of traces of contaminants with high selectivity and efficiency. Also, the design of tailored nanocomposites facilitates their separation from the environment, their reuse and often the recovery of the target pollutant.

Carbon nitride has proven to be an excellent candidate for environmental decontamination (Asadzadeh-Khaneghah and Habibi-Yangjeh 2020). Indeed, carbon nitride is a metal-free and visible-light-responsive photocatalyst that has shown high performance for environmental applications (Ong et al. 2016). Its graphitic form (g-C₃N₄) – commonly obtained from the pyrolysis of carbon and nitrogen-rich molecules – presents several advantages such as easy preparation, inexpensive, high efficiency, remarkable chemical stability and low toxicity (Zhu et al. 2014). Also, pure g-C₃N₄ has demonstrated efficacy in remediation against different emerging pollutants due to its high adsorption potential and impressive photocatalytic performance. However, the potential for g-C₃N₄ modification through the incorporation of diverse nanocompounds offers an opportunity to introduce novel physical and physicochemical characteristics to the resulting nanocomposites (Rosa et al. 2023; Ahmadi et al. 2023). By synergistically combining the inherent properties of g-C₃N₄ with those of the integrated phase, this approach can provide a larger array of reactive sites and heterojunctions enhancing its capacity to capture and degrade a broader spectrum of compounds. Remarkably, the decoration of g-C₃N₄ with magnetic nanoparticles (NPs) results in magneto-responsive adsorbent platforms that can be remotely manipulated by external magnetic fields, allowing easy recovery and cycling in remediation techniques (Mousavi et al. 2018).

Methylene blue MB is a toxic cationic dye used in several industrial sectors and often applied as a model in adsorption/degradation studies (Oladoye et al. 2022). Particularly, the removal of MB from aqueous solutions at different conditions has been investigated using pure g-C₃N₄ (Paul et al. 2019; Ashrafi et al. 2020; Nguyen et al. 2021) and magnetically-modified g-C₃N₄ nanocomposites (Hassani et al., 2018; Rosa et al., 2021; Sahoo et al., 2020; Waheed et al., 2023). Most of these surveys limit their investigations to low and high pH conditions despite showing these photocatalysts can remove almost 100% of MB in more acidic or more basic conditions. However, an enhanced removal capacity is highly desirable in neutral medium, especially for revery day life and scalable applications. The Global Effluent Guidelines (Global Effluent Guidelines requirements, 2007) along with the most important standards applied in the dyeing industry on many continents stipulate that the pH of treated effluents should fall within the 6 to 9 range prior to their discharge into the environment.

In this context, the main goal of this article is the elaboration of carbon nitride-derived magnetic nanocomposites based on g-C₃N₄ sheets decorated with in situ-synthesized magnetite (Fe₃O₄) NPs with spherical and nanoflower-like morphology and their use for contaminant degradation and removal at neutral pH conditions, not requiring a pH adjustment for the treatment. The detailed characterization of the nanocomposites in terms of structure, morphology, and surface composition, along with textural, optical, and electronic properties is discussed. Then, the association of the capacity of adsorption and photocatalytic activity for removal of MB from water are investigated to probe the resulting physical and physicochemical properties of magnetically-driven materials for an improved the removal of the contaminant at neutral pH.

Samples

Graphitic carbon nitride powder – gC₃N₄ (sample CN) – was obtained by the calcination of a mixture of urea and melamine (1:1 in mass) under air atmosphere using a ceramic crucible, at 5°C/min to 550°C, for 4 hours (Rosa et al. 2021).

The incorporation of the magnetic phase to form the nanocomposites was carried out via in situ chemical synthesis of Fe₃O₄ nanostructures in the carbon nitride sheets. As schematized in Fig. 1, spherical Fe₃O₄ NPs were deposited in the g-C₃N₄ templates using the traditional coprecipitation of iron salts (Rosa et al. 2021). Briefly, 185 mg of g-C₃N₄ (sample CN) were sonicated in 25 mL of ultrapure water for 50 min with 0.50 mmol of FeCl₃·6H₂O and 0.25 mmol of FeCl₂·4H₂O. Next, 1.5 mL of concentrated NH₄OH was added to the mixture at 80°C, under magnetic agitation for 30 min. The precipitate (sample S-CN) was washed with acetone and water and dried at 80°C. Magnetite nanoflowers were deposited in the g-C₃N₄ templates using a solvothermal precipitation method. In brief, 185 mg of sample CN were sonicated with 0.80 mmol of FeCl₃·6H₂O, 55.0 mg of citric acid, and 345 mg of urea in 15 mL of ethylene glycol for 30 min. Then, the mixture was heated in a Teflon-lined autoclave (150 mL) at 200°C for 18 h. The precipitate (sample NF-CN) was washed with acetone and water and dried at 80°C.

Characterization

X-ray powder diffraction (XRD) was performed using a Rigaku Miniflex 600 diffractometer at 40 kV and 30 mA (Cu Kα = 1.541 Å). Transmission Electron Microscopy (TEM) was performed using a JEOL JEM-2100 microscope. Nitrogen adsorption-desorption isotherms were obtained with a Micromeritics ASAP-2050 porosimeter. Brunauer-Emmett-Teller (BET) formalism and Barrett–Joyner–Halenda (BJH) adsorption pore distribution data were utilized to evaluate the specific surface area and the cumulative pore volume along with the average pore size respectively. Magnetization hysteresis loops of samples were recorded with a EV9-ADE (Magnetics) magnetometer at 300 K. Fourier transform infrared spectroscopy (FTIR) was performed in the 4000–400 cm^− 1 range with a IRPrestige-21(Shimadzu) Spectrophotometer, using conventional KBr pellets. The surface charge of the nanomaterials as a function of pH was characterized through zeta potential experiments using a Nano ZS Zetasizer coupled with a MPT-2 auto titrator (Malvern). Zeta potentials were obtained from electrophoretic mobilities using the Smoluchowski approximation. Photoluminescence (PL) spectra were recorded in a HORIBA Scientific FluoroLog-3 Modular spectrofluorometer with excitation wavelength = 350 nm. The band gap value of samples was calculated by the absorption spectra obtained by Diffuse Reflectance Spectra with a Varian 5000 UV- spectrophotometer, in the 300 to 700 nm range.

Adsorption and photocatalytic activity measurements

The efficiency of the nanomaterials to degrade methylene blue (MB) under different pH conditions was assessed in duplicate tests from two situations: dark adsorption for 70 min (equilibrium time set from standard experiments) and photocatalysis tests under visible light for 120 min. The batch tests were conducted at 25°C and shaking rate of 400 rpm, in three pH values (4.5; 6.9 and 10.6). In the dark adsorption step, 15 mg of the nanomaterial was added to 50 mL of MB solution (8.0 mg/L) and placed in an open reactor. At 10 min intervals, two aliquots of 1 mL were collected from the system, placed in microtubes, and submitted to centrifugation at 4000 rpm for 4 min. The concentration of the dye in the supernatant phase was analyzed by UV–vis spectroscopy (spectrophotometer Avantes, model Avalight DHS) at a maximum wavelength of 664.34 nm, using external calibration. The aliquots, after homogenization, were returned to the reactor. After the adsorption tests, the system was exposed to a visible-light source (6500 K Cool White 50 W LED, 3000 Lumens) for 120 min to perform degradation by photocatalysis. In these experiments, aliquots of 1 mL were collected in 15 min intervals.

After reaching the equilibrium, the amount (q_e) of dye adsorbed on the nanomaterials (mg/g) was determined as,

$${q}_{e}=\frac{{(C}_{0}-{C}_{e})}{m}\bullet V$$

where C₀ (mg/L) and C_e (mg/L) correspond the initial and equilibrium MB concentrations, respectively. V is the volume of solution and m is the weight of the nanomaterial. The kinetics of MB adsorption was studied using the pseudo-second-order (PSO) model in its linearized form (Tran et al. 2017)according to:

$$\frac{t}{{q}_{t}}=\frac{1}{{k}_{2}{{q}_{e}}^{2}}+\frac{t}{{q}_{e}}$$

where q_t corresponds to the amount of dye adsorbed (mg/g) at time t, while k₂ is the rate constant associated with the PSO model (g mg^− 1 min^− 1). The kinetic performance of the samples was evaluated from the 2nd-order rate index k₂q_e (min^− 1) (Wu et al. 2009).

Regarding the photocatalytic degradation, its kinetics was studied from the logarithmic form of the pseudo-first-order (PFO) model as,

$$ln\left(\frac{{C}_{t}}{{C}_{0}}\right)={-k}_{app}t$$

where C_t (mg/L) is the MB concentration at time t and k_app is the apparent PFO rate constant.

The TEM image of sample CN (Fig. 2a) shows the layered and flattened crystallites of g-C₃N₄ with irregular morphology produced through thermal polycondensation. The inset circle of Fig. 2a shows an HRTEM micrograph that highlights an in-plane arrangement, typical of g-C₃N₄ platelets. The XRD pattern (bottom of Fig. 2a) exhibits the (100) and (002) peaks, respectively at 13.1° and 27.4°, confirming that the graphitic stacking structure of g-C₃N₄ was formed through polycondensation of melamine and urea (Sunasee et al. 2019).

The TEM images depicted in Figs. 2b to 2e exhibit a uniform distribution of iron oxide magnetic NPs decorating the g-C₃N₄ sheets in the nanocomposite samples. In Fig. 2b, nearly spherical single-core Fe₃O₄ NPs (magnified in Fig. 2c) can be observed (sample S-CN). Figure 2d shows the formation of nanoflower-like Fe₃O₄ nanostructures (sample NF-CN). As expected, these nanoflowers are multicore larger structures formed by stacked smaller spherical Fe₃O₄ nanostructures (Gavilán et al. 2017), as shown in the inset of Fig. 2d and magnified in Fig. 2e.

Table 1 collects the values of average diameter (d_TEM) and polydispersity index (s) of NPs of samples S-CN and NF-CN calculated from the size-distribution curves (Fig. 2f).

After decoration with magnetic NPs, nanocomposites preserved the typical diffraction peaks of the g-C₃N₄ phase. Also, the extra peaks relative to the spinel phase (indexed and shown in Fig. 2g) confirmed the presence of the Fe₃O₄ NPs in the graphitic g-C₃N₄ template structure. Scherrer's formula was utilized to determine the crystallite size of the incorporated magnetite NPs (d_XRD) considering the (311) diffraction peak (Table 1). In the case of sample S-CN, the mean diameter agrees well with TEM results. However, the Fe₃O₄ NPs of sample NF-CN present a mean size significantly smaller than that obtained from TEM. This discrepancy is due to the fact that in nanoflowers the XRD size is related to the individual spherical NPs stacked in the flower-like structure, as shown in Fig. 2f (Gavilán et al. 2017).

Table 1

Parameters of samples characterization: mean characteristic sizes (d_TEM, d_XRD), polydispersity index (s_TEM), BET specific surface area (S_BET), pore volume (PV), average pore-size diameter (PD), band gap energy, and saturation magnetization (M_S).
Sample	d_TEM (nm)	s_TEM	d_XRD (nm)	M_S (emu/g)	band gap (eV)	S_BET (m²/g)	PV (cm³/g)	PD (nm)
CN	-	-	-	-	2.53	15.0	0.19	33.1
S-CN	14.3	0.38	13.8	14.3	1.99	52.7	0.26	19.1
NF-CN	180.3	0.44	9.0	21.9	1.85	96.6	0.31	13.8

The magnetic behavior of g-C₃N₄ samples decorated with magnetite NPs is shown in Fig. 2h. Both samples exhibit a superparamagnetic-like behavior with almost no coercivity or remanence, as seen from the hysteresis loops in low-field in the inset. The saturation magnetization (M_S) of sample NF-CN is higher than that of sample S-CN and, which can be correlated to the size of the magnetic structures in the nanocomposites (Table 1). Indeed, since the mass fraction of Fe₃O₄ determined from ICP-OES is almost the same in both nanocomposites (25% in S-CN and 27% in NF-CN), the higher saturation magnetization of sample NF-CN arises from the larger Fe₃O₄ nanoflower structures (Gavilán et al. 2017) compared to the single-core smaller magnetite nanoparticles (Sousa et al. 2005) of sample S-CN. Nonetheless, using a permanent magnet, both decorated samples can be easily separated or manipulated from the liquid media (Fig. 2h), which improve their performance in pollutant removal.

Figure 3. PL spectra (3a), N₂ adsorption/desorption isotherms (3b), FTIR spectra (3c), and pH-dependence of zeta potential of the samples (3d).

The nanocomposites and pristine g-C₃N₄ exhibit the expected optical properties of semiconductors. Sample CN shows a maximum PL peak at approximately 410 nm with a low absorption in the red-light range, which is characteristic of carbon nitride synthesized through thermal polycondensation (Zhan et al. 2017). The incorporation of iron oxide nanoparticles causes a redshift in the onset of optical absorption, resulting in a maximum PL peak at > 450 nm, suggesting an improved visible absorption of the nanocomposites. The band gaps calculated from absorption edges, as shown in Figure S1 in Supplementary Material, were around 2.53 eV, 1.99 eV, and 1.85 eV, for samples CN, S-CN and NF-CN, respectively. These results demonstrate that the incorporation of iron oxide NPs enhances the visible-light response-ability as reported elsewhere (Irfan et al. 2019).

Figure 3b shows the N₂ adsorption/desorption isotherms for all samples. It can be observed a typical IUPAC type IV pattern with h3 hysteresis loops, characteristic of mesoporous structure in the form of parallel plates (Fuentez-Torres et al. 2021). The values of BET surface area (S_BET), cumulative pore volume (PV) and pore size (PD) listed in Table 1 indicate the modification of the g-C₃N₄ template with Fe₃O₄ NPs sharply enhances the surface area of the nanocomposites.

The characteristic vibration modes assigned to the g-C₃N₄ phase can be observed in the pristine and nanocomposite samples, as seen in the FTIR spectra of Fig. 3c (Hu et al. 2014; Zhong et al. 2020). The bands observed between 800 and 900 cm^− 1 can be attributed to tri-s-triazine, suggesting that the skeletal structure of the g-C₃N₄ remained unaltered in decorated samples. The characteristic vibrations of aromatic CN heterocycles found in g-C₃N₄ can be identified as strong bands ranging from 1700 to 1200 cm^− 1. The bands observed between 3400 and 2900 cm^− 1 can be assigned to N-H residual components, which corresponds to amines (primary and secondary). The nanocomposite samples exhibit additional bands related to the presence of iron oxide nanoparticles (Rubim et al. 2001). The band at 580 cm^− 1 can be attributed to Fe − O vibrations in the tetrahedral sites of the spinel crystalline lattice of Fe₃O₄ nanoparticles. This finding confirms that the Fe₃O₄ nanoparticles were successfully integrated into the g-C₃N₄ structure.

Figure 3d exhibits the variation of the zeta potential of the samples under the different pH conditions utilized to study the adsorption-photocatalytic efficiency of the nanocomposites. For all samples, the zeta potential becomes more negative with increasing pH. In the case of CN, this behavior may be due to the substitution of ≡ C-NH₂ chemical groups on the g-C₃N₄ surface by ≡ C-OH groups, which undergo increasing deprotonation (≡ C-O⁻) with pH (Zhu et al. 2015). The zeta potential of the nanocomposite samples showed a similar pH-dependent behavior, with higher absolute values of zeta potential for pH > 7, around − 30 mV. This phenomenon may be associated with the presence of magnetite nanoparticles on the g-C₃N₄ surface, whose hydroxyl groups (≡ FeOH) are mostly deprotonated (≡ FeO⁻) in strongly alkaline medium (Palomec-Garfias et al. 2018).

The kinetics of MB adsorption during the dark stage for different pH conditions is depicted in Fig. 4. As a general trend, the adsorption rate is very fast in the first minutes, then gradually decreases reaching the equilibrium within 70 min. The adjust of the kinetic results with the PSO model is shown in Fig. S2 in Supplementary Material, and Table S1 in Supplementary Material collects the obtained adjusted parameters. Most of the R_W values lie in the range of 0.1 to 0.01 for all samples, indicating a highly curved adsorption curve and well-approaching equilibrium (Wu et al. 2009). Based on the pseudo-second-order rate index (k₂q_e), in acidic medium the MB adsorption is faster for sample CN while in neutral and alkaline media the kinetic performance is higher in the case of the nanocomposites.

To better compare the removal results obtained, a heat map with the percentage of adsorption, photodegradation and total MB removal of all nanocomposites under different pH conditions was plotted in Fig. 5, where the darker blue bars indicate the highest MB removal percentages. Concerning the equilibrium adsorption capacity, all samples exhibit a higher MB adsorption in alkaline medium (Fig. 5). This behavior may be attributed to zeta potential values, which are more negative at this pH condition, favoring electrostatic attraction between the surface sites of the nanomaterials and cationic MB species, then higher adsorption. It is noteworthy that the nanocomposites present higher adsorption capacities than the pure g-C₃N₄ in all pH conditions, due to their larger specific surface area and, therefore higher number of active sorption sites.

Unlike the adsorption capacity, incorporating the magnetic phase did not improve the activity of g-C₃N₄ towards MB photodegradation. Indeed, the photocatalytic efficiency of pure g-C₃N₄ is larger than that of nanocomposites under all pH conditions (Fig. 5). Also, the higher values of the rate constants obtained from the PFO model (Fig. S2) indicate that the MB photodegradation is faster for pure g-C₃N₄, no matter the pH of the medium (Table S1). This lower performance of the nanocomposites may result from covering a fraction of active sites of the g-C₃N₄ surface by the magnetic nanoparticles, which blocks visible light absorption, thereby decreasing photodegradation. It should be noted that MB molecules suffer photoinduced self-degradation, which is negligible in low pH, but sharply increases towards high pH conditions, as already reported (Soltani and Entezari 2013; Xu et al. 2015).

The performance of the samples on solutions discoloration (total MB removal) under the three pH conditions can be evaluated from the association of adsorption and photocatalytic capacities (Fig. 5). In acidic medium, the pure g-C₃N₄ is more efficient and can remove approximately 95% of MB molecules mainly thanks to its high photocatalytic efficiency. In alkaline medium, there is no significant difference in performance among the three nanomaterials, where the removal capacity is around 90%. However, in neutral medium, NF-CN is considerably more efficient (80.7%) than the others, which is related to its enhanced adsorption capacity in this pH region. Indeed, the decoration of the g-C₃N₄ with Fe₃O₄ nanoflowers endows the nanocomposite with more negative zeta potential and larger surface area, remarkably improving its adsorption capacity.

Depending on the photocatalyst concentration, irradiation time and lamp power, some g-C₃N₄-based photocatalysts can remove up to 100% of MB from water in low and high pH conditions, similar to the nanomaterials proposed here (Hassani et al. 2018; Paul et al. 2019; Sahoo et al. 2020; Ashrafi et al. 2020; Nguyen et al. 2021; Rosa et al. 2021; Waheed et al. 2023). However, sample NF-CN reaches a high adsorption capacity even in neutral medium, which is highly desirable for real-life applications in the dyeing industry (Global Effluent Guidelines requirements, 2007).

This survey shows the feasibility of preparing magnetically-driven nanocomposites with different adsorption and photocatalytic properties and their efficiency toward MB removal from aqueous solutions in varying pH conditions. The nanomaterials were obtained by inserting magnetic Fe₃O₄ nanoparticles with spherical and nanoflower-like morphologies, synthesized in situ by two different methods, in a same g-C₃N₄ matrix obtained by pyrolysis of carbon and nitrogen-rich molecules. The incorporation of the magnetic phase mainly improved the visible-light response-ability and the specific surface area of the nanocomposites. In alkaline region, the samples exhibited an equivalent removal capacity, while in acidic conditions the pure g-C₃N₄ was more effective. However, in neutral medium, the nanocomposite with the Fe₃O₄ nanoflowers showed a remarkable removal efficiency compared to the pure g-C₃N₄ and the sample with spherical magnetic particles thanks to a good compromise of a high adsorption capacity and a good photocatalytic activity. These findings show that the proposed g-C₃N₄ nanocomposites decorated with Fe₃O₄ nanoflowers may be a viable alternative to remove MB from water, as they can be efficiently used in neutral conditions, avoiding critical pH adjustments of the treated effluents. This is a key factor for compliance with the most important international guidelines applied to the dying industry, which establish that the pH of remediated effluents must be at 6 to 9 before releasing into the environment. Moreover, the nanocomposite can be easily separated and recovered by using magnetic assistance, ensuring its reusability, which can be extended to other types of cationic dyes. Ultimately, our results are relevant for future applications in large-scale setups and in real polluted samples, and the proposed synthesis strategy can be used as a framework to tune g-C₃N₄ matrices with magnetic nanoparticles of other shapes (cubes, nanorods) aiming for advanced photoremediation properties.

Acknowledgments

The authors gratefully acknowledge the financial support from the following Brazilian Agencies: Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and Fundação de Apoio a Pesquisa do Distrito Federal (FAPDF). M.H.S. acknowledges CNPq grant number 315627/2021-2 and FAPDF grant numbers 00193.00000767/2021-15, 00193-00001264/2021-67 and 0193.00002588/2022-01. The authors would like to thank Dr. Tatiane Oliveira dos Santos from the High-Resolution Microscopy Multi-User Laboratory at the Federal University of Goiás, Brazil, for the electron microscopy measurements.

Ethical Approval

Not applicable

Consent to Participate

Not applicable

Consent to Publish

Not applicable

Authors Contributions

The authors’ contributions to this article are as follows: Fernanda Lopes Rodovalho – Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Writing (original draft). Eliane Vieira Rosa – Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Writing (original draft). Atailson Oliveira da Silva – Formal analysis, Methodology, Writing (review & editing). Sergio Enrique Moya – Investigation, Writing (review & editing). Alex Fabiano Cortez Campos – Conceptualization, Formal analysis, Supervision, Writing (review & editing). Marcelo Henrique Sousa – Conceptualization, Formal analysis, Funding acquisition, Investigation, Project administration, Supervision, Writing (review & editing). All authors read and approved the final manuscript.

Funding

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) – Grant number 315627/2021-2 and Fundação de Apoio a Pesquisa do Distrito Federal (FAPDF) – Grant numbers 00193.00000767/2021-15, 00193-00001264/2021-67 and 0193.00002588/2022-01.

Competing Interests

The authors have no relevant financial or non-financial interests to disclose.

Ahmadi A, Hajilou M, Zavari S, Yaghmaei S (2023) A comparative review on adsorption and photocatalytic degradation of classified dyes with metal/non-metal-based modification of graphitic carbon nitride nanocomposites: Synthesis, mechanism, and affecting parameters. J Clean Prod 382:134967. https://doi.org/10.1016/j.jclepro.2022.134967
Asadzadeh-Khaneghah S, Habibi-Yangjeh A (2020) g-C3N4/carbon dot-based nanocomposites serve as efficacious photocatalysts for environmental purification and energy generation: A review. J Clean Prod 276:124319. https://doi.org/10.1016/j.jclepro.2020.124319
Ashrafi H, Akhond M, Absalan G (2020) Adsorption and photocatalytic degradation of aqueous methylene blue using nanoporous carbon nitride. J Photochem Photobiol A Chem 396:112533. https://doi.org/10.1016/j.jphotochem.2020.112533
Fuentez-Torres MO, Ortiz-Chi F, Espinosa-González CG, et al (2021) Facile Synthesis of Zn Doped g-C3N4 for Enhanced Visible Light Driven Photocatalytic Hydrogen Production. Top Catal 64:65–72. https://doi.org/10.1007/s11244-020-01298-9
Gavilán H, Sánchez EH, Brollo MEF, et al (2017) Formation Mechanism of Maghemite Nanoflowers Synthesized by a Polyol-Mediated Process. ACS Omega 2:7172–7184. https://doi.org/10.1021/acsomega.7b00975
Global Effl uent Guidelines requirements (2007) Global Effluent Guidelines (Online). Available: http://www.levistrauss.com/wp-content/uploads/2014/01/Global-Effluent-Guidelines.pdf (accessed: 04.09.2023)
Hassani A, Eghbali P, Ekicibil A, Metin Ö (2018) Monodisperse cobalt ferrite nanoparticles assembled on mesoporous graphitic carbon nitride (CoFe2O4/mpg-C3N4): A magnetically recoverable nanocomposite for the photocatalytic degradation of organic dyes. J Magn Magn Mater 456:400–412. https://doi.org/10.1016/j.jmmm.2018.02.067
Hu S, Jin R, Lu G, et al (2014) The properties and photocatalytic performance comparison of Fe3+-doped g-C3N4 and Fe2O3/g-C3N4 composite catalysts. RSC Adv 4:24863. https://doi.org/10.1039/c4ra03290j
Irfan M, Sevim M, Koçak Y, et al (2019) Enhanced photocatalytic NOx oxidation and storage under visible-light irradiation by anchoring Fe3O4 nanoparticles on mesoporous graphitic carbon nitride (mpg-C3N4). Appl Catal B 249:126–137. https://doi.org/10.1016/j.apcatb.2019.02.067
Manoiu V-M, Kubiak-Wójcicka K, Craciun A-I, et al (2022) Water Quality and Water Pollution in Time of COVID-19: Positive and Negative Repercussions. Water (Basel) 14:1124. https://doi.org/10.3390/w14071124
Mousavi M, Habibi-Yangjeh A, Pouran SR (2018) Review on magnetically separable graphitic carbon nitride-based nanocomposites as promising visible-light-driven photocatalysts. Journal of Materials Science: Materials in Electronics 29:1719–1747. https://doi.org/10.1007/s10854-017-8166-x
Nguyen TKA, Pham T-T, Nguyen-Phu H, Shin EW (2021) The effect of graphitic carbon nitride precursors on the photocatalytic dye degradation of water-dispersible graphitic carbon nitride photocatalysts. Appl Surf Sci 537:148027. https://doi.org/10.1016/j.apsusc.2020.148027
Oladoye PO, Ajiboye TO, Omotola EO, Oyewola OJ (2022) Methylene blue dye: Toxicity and potential elimination technology from wastewater. Results in Engineering 16:100678. https://doi.org/10.1016/j.rineng.2022.100678
Ong W-J, Tan L-L, Ng YH, et al (2016) Graphitic Carbon Nitride (g-C ₃ N ₄ )-Based Photocatalysts for Artificial Photosynthesis and Environmental Remediation: Are We a Step Closer To Achieving Sustainability? Chem Rev 116:7159–7329. https://doi.org/10.1021/acs.chemrev.6b00075
Palomec-Garfias AF, Jardim KV, Sousa MH, Márquez-Beltrán C (2018) Influence of polyelectrolyte chains on surface charge and magnetization of iron oxide nanostructures. Colloids Surf A Physicochem Eng Asp 549:13–24. https://doi.org/10.1016/j.colsurfa.2018.03.070
Paul DR, Sharma R, Nehra SP, Sharma A (2019) Effect of calcination temperature, pH and catalyst loading on photodegradation efficiency of urea derived graphitic carbon nitride towards methylene blue dye solution. RSC Adv 9:15381–15391. https://doi.org/10.1039/C9RA02201E
Raza T, Shehzad M, Abbas M, et al (2023) Impact assessment of COVID-19 global pandemic on water, environment, and humans. Environmental Advances 11:100328. https://doi.org/10.1016/j.envadv.2022.100328
Rosa EV, Campos AFC, Rodrigues MO, et al (2023) 4 - Nano-engineered composites based on carbon nitride as potential agents for the remediation of water with micropollutants. In: Henini M, Rodrigues MO (eds) Quantum Materials, Devices, and Applications. Elsevier, pp 87–115
Rosa E V., Fascineli ML, da Silva ICR, et al (2021) Carbon nitride nanosheets magnetically decorated with Fe3O4 nanoparticles by homogeneous precipitation: Adsorption-photocatalytic performance and acute toxicity assessment. Environ Nanotechnol Monit Manag 16:100549. https://doi.org/10.1016/j.enmm.2021.100549
Rubim JC, Sousa MH, Silva JCO, Tourinho FA (2001) Raman spectroscopy as a powerful technique in the characterization of ferrofluids. Brazilian Journal of Physics 31:402–408. https://doi.org/10.1590/S0103-97332001000300010
Sahoo SK, Padhiari S, Biswal SK, et al (2020) Fe3O4 nanoparticles functionalized GO/g-C3N4 nanocomposite: An efficient magnetic nanoadsorbent for adsorptive removal of organic pollutants. Mater Chem Phys 244:122710. https://doi.org/10.1016/j.matchemphys.2020.122710
Soltani T, Entezari MH (2013) Photolysis and photocatalysis of methylene blue by ferrite bismuth nanoparticles under sunlight irradiation. J Mol Catal A Chem 377:197–203. https://doi.org/10.1016/j.molcata.2013.05.004
Sousa EC, Alves CR, Aquino R, et al (2005) Experimental evidence of surface effects in the magnetic dynamics behavior of ferrite nanoparticles. J Magn Magn Mater 289:118–121. https://doi.org/10.1016/j.jmmm.2004.11.035
Sunasee S, Leong KH, Wong KT, et al (2019) Sonophotocatalytic degradation of bisphenol A and its intermediates with graphitic carbon nitride. Environmental Science and Pollution Research 26:1082–1093. https://doi.org/10.1007/s11356-017-8729-7
Tran HN, You S-J, Hosseini-Bandegharaei A, Chao H-P (2017) Mistakes and inconsistencies regarding adsorption of contaminants from aqueous solutions: A critical review. Water Res 120:88–116. https://doi.org/10.1016/j.watres.2017.04.014
Waheed IF, Hamad MA, Jasim KA, Gesquiere AJ (2023) Degradation of methylene blue using a novel magnetic CuNiFe2O4/g-C3N4 nanocomposite as heterojunction photocatalyst. Diam Relat Mater 133:109716. https://doi.org/10.1016/j.diamond.2023.109716
Wang Q, Yang X (2021) How do pollutants change post-pandemic? Evidence from changes in five key pollutants in nine Chinese cities most affected by the COVID-19. Environ Res 197:111108. https://doi.org/10.1016/j.envres.2021.111108
Werkneh AA, Rene ER (2019) Applications of Nanotechnology and Biotechnology for Sustainable Water and Wastewater Treatment. pp 405–430
Wu F-C, Tseng R-L, Huang S-C, Juang R-S (2009) Characteristics of pseudo-second-order kinetic model for liquid-phase adsorption: A mini-review. Chemical Engineering Journal 151:1–9. https://doi.org/10.1016/j.cej.2009.02.024
Xu H-Y, Wu L-C, Zhao H, et al (2015) Synergic Effect between Adsorption and Photocatalysis of Metal-Free g-C3N4 Derived from Different Precursors. PLoS One 10:e0142616. https://doi.org/10.1371/journal.pone.0142616
Zhan Y, Liu Z, Liu Q, et al (2017) A facile and one-pot synthesis of fluorescent graphitic carbon nitride quantum dots for bio-imaging applications. New Journal of Chemistry 41:3930–3938. https://doi.org/10.1039/C7NJ00058H
Zhong C-R, Lee T-W, Li J-A, et al (2020) Origin of the enhanced photocatalytic activity of graphitic carbon nitride nanocomposites and the effects of water constituents. Carbon N Y 167:852–862. https://doi.org/10.1016/j.carbon.2020.06.028
Zhu B, Xia P, Ho W, Yu J (2015) Isoelectric point and adsorption activity of porous g-C3N4. Appl Surf Sci 344:188–195. https://doi.org/10.1016/j.apsusc.2015.03.086
Zhu J, Xiao P, Li H, Carabineiro SAC (2014) Graphitic Carbon Nitride: Synthesis, Properties, and Applications in Catalysis. ACS Appl Mater Interfaces 6:16449–16465. https://doi.org/10.1021/am502925j

NanoflowersESPRSupplementary.pdf

Download PDF

Journal Publication

published 25 Jan, 2024

Read the published version in Environmental Science and Pollution Research →

Reviewers agreed at journal
08 Nov, 2023
Reviewers invited by journal
07 Nov, 2023
Editor assigned by journal
25 Oct, 2023
First submitted to journal
20 Oct, 2023

You are reading this latest preprint version

Enhancing the efficiency of magnetically-driven carbon nitride-based nanocomposites with magnetic nanoflowers for the removal of methylene blue dye at neutral pH

Status:

Journal Publication

Version 1

Abstract

Figures

Introduction

Material and methods

Samples

Characterization

Adsorption and photocatalytic activity measurements

Results and Discussion

Conclusions

Declarations

References

Supplementary Files

Status:

Journal Publication

Version 1