SMO/G-C3N4 NANOCOMPOSITES FOR DYE INDUSTRIES WASTEWATER TREATMENT

Abstract

The present invention relates to a nanocomposite of SmO/g-C3N4 were fabricated and used as a photocatalyst for the degradation of anionic dyes, cationic dyes, and mix dyes due to their high specific surface area and outstanding photocatalytic capabilities. The photocatalytic activity of SmO/g-C3N4 nanocomposites was studied against anionic dyes (Rose bengal (RB) and Xylenol Orange (XO)), cationic dyes (Auramine O (AO) and Crystal Violet (CV)) and their mixture (Mix Dyes). The results indicated that SmO/g-C3N4 nanocomposite (SmG-1.5) exhibited superior photocatalytic activity compared to its precursors, degrading dyes at rates of Rose bengal-84.7%, Xylenol Orange-75.3%, Auramine O-82.2%, Crystal Violet-72.3%, and Mix dyes-80%. Thus, SmO/g-C3N4 nanocomposites demonstrate significant potential as an efficient photocatalyst for degrading dyes in wastewater.

Specification

Description:FIELD OF THE INVENTION
The present invention generally relates to the field of nanocomposite. The invention, particularly relates to a nanocomposite for degrading dyes comprising of Graphite Carbon Nitride (g-C3N4) and Samarium Oxide (SmO) in varying ratios. preparation method of nanocomposite of SmO and g-C3N4 is also disclosed.

BACKGROUND OF THE INVENTION
Textile wastewater has been found to contain a wide range of toxic dyes, heavy metals, such as mercury, chromium, cadmium, lead, and arsenic which are required in the production of textile dye color pigments, as well as aromatic compounds. The presence of heavy metals such as mercury, chromium, cadmium, lead, and arsenic is required in the production of textile dye color pigments. These toxic chemicals are transported over long distances together with the wastewater. They then remain in the water and soil for long periods of time, posing serious health risks to living organisms and reducing soil fertility as well as the photosynthetic activity of aquatic plants, resulting in the development of anoxic conditions for aquatic fauna and flora. Textile dyes also degrade the esthetic quality of water bodies by increasing biochemical and chemical oxygen demand, thereby impairing photosynthesis, inhibiting plant growth, entering the food chain, providing recalcitrance and bioaccumulation, and potentially promoting toxicity, mutagenicity, and carcinogenicit. The large amounts of water used in fabric manufacturing result in equally large amounts of wastewater containing high levels of dissolved solids, organics, metals, salts, and recalcitrant dyes, because of the high durability and solubility of synthetic dyes in water, conventional treatment options are frequently ineffective, while secondary pollution and inefficient removal of organic load upon discoloration necessitate the use of advanced approaches. Therefore, there is an urgent need to develop cost-effective and environmentally friendly treatment approaches for adequately treating dye-containing wastewater prior to its final disposal into the environment. Under this premise, this review will provide a detailed knowledge on the adverse impacts of dye-containing textile wastewater on natural ecosystems and living organisms along with the various existing and advanced treatment approaches for the better management of textile wastewater with a view to working towards environmental safety. The untreated effluents released by the textile industry contain a diverse range of organic pollutants, the most prevalent of which are textile dyes. Azo dyes, which contain one or more azo groups structurally, are the largest class (above 60%) among the various groups of textile dyes and the most widely used dyes in the textile industry. Inefficient textile dyeing processes cause 15-50% of azo dyes that are not bound to fibers and fabrics to be released into generated wastewater. Some textile factories treat their wastewater to degrade the free azo dyes released into the environment, while others discharge untreated industrial effluents directly into bodies of water, posing serious ecotoxicological threats as well as toxic effects on living organisms. Farmers in developing countries used to irrigate their agricultural lands with wastewater containing untreated industrial effluents, which had a negative impact on soil quality and crop germination rate.
Generally speaking, nanomaterials describe materials of which the structural components are sized (in at least one dimension) between 1 and 100?nm. Due to the nanoscale size of nanomaterials, their properties, such as mechanical, electrical, optical, and magnetic properties, are significantly different from conventional materials. A wide range of nanomaterials have the characteristics of catalysis, adsorption, and high reactivity. In the past decades, nanomaterials have been under active research and development and have been successfully applied in many fields, such as catalysis, medicine, sensing, and biology. In particular, the application of nanomaterials in water and wastewater treatment has drawn wide attention. Due to their small sizes and thus large specific surface areas, nanomaterials have strong adsorption capacities and reactivity. What is more, the mobility of nanomaterials in solution is high. Heavy metals, organic pollutants, inorganic anions, and bacteria have been reported to be successfully removed by various kinds of nanomaterials. On the basis of numerous studies, nanomaterials show great promise for applications in water and wastewater treatment. At present, the most extensively studied nanomaterials for water and wastewater treatment mainly include zero-valent metal nanoparticles, metal oxides nanoparticles, carbon nanotubes (CNTs), and nanocomposites.
A number of different types of materials and various method for synthesizing nanoparticle are available in the prior art. For example, the following patents are provided for their supportive teachings and are all incorporated by reference: A non-patent literature discloses CNF/CS composite beads were prepared by dissolving cellulose and CS in LiBr molten salt hydrate and regenerating in ethanol. This preparation method is facile and efficient, and the obtained porous CNF/CS beads with the weight ratio of 8:2 exhibited a large specific surface area, uniform micro-nano-sized pores, strong mechanical property, and water absorption-resistance. Moreover, these beads as drug (tetracycline hydrochloride, TH) carriers showed a higher encapsulation efficiency (47.4%) at the TH concentration of 5 mg/mL in 24 h, and a higher drug loading rate (12.0%) than pure CNF and other CNF/CS beads prepared with different ratios. In addition, the TH releasing behavior of CNF/CS (8:2) beads fitted well into the zero-order, first-order, and Higuchi models under an acid condition, indicating that the drug release of these pH-sensitive beads was mainly affected by drug concentration under an acid condition. Therefore, these CNF/CS beads have great potential to be used as drug carriers for medical applications.
Another prior art document, CN108940338B, discloses a potassium element doped porous carbon nitride photocatalyst, a preparation method and application thereof. The preparation method comprises the following steps: and mixing the porous carbon nitride material with a potassium salt solution, drying, and calcining the obtained mixture at high temperature to obtain the potassium-doped porous carbon nitride photocatalyst. The photocatalyst has the advantages of large specific surface area, large number of holes, high separation and migration rate of photon-generated carriers, strong light absorption capacity, high photocatalytic activity and the like, is a novel visible-light photocatalyst with novel structure and excellent photocatalytic performance, and has good use value and application value, and the preparation method has the advantages of simple process, easy operation, low cost and the like. The photocatalyst can be widely used for degrading organic pollutants, can effectively remove the organic pollutants, has the advantages of simple operation, low cost, good removal effect and the like, and has good application prospect.
Yet another prior art document, US10974230B2, discloses a composite synthesized by the steps of preparing a solution having a carbon source material and a heteroatom containing additive; evaporating the solution to yield a plurality of powders; and subjecting the plurality of powders to a heat treatment for a duration of time effective to produce a doped carbon composite.
Yet another prior art document, CN112742355A disclosed a chitosan-based composite aerogel microbead heavy metal ion adsorption material and a preparation method and application thereof. The chitosan-based composite aerogel microbead heavy metal ion adsorption material with high adsorption capacity, high adsorption efficiency and excellent mechanical properties is successfully prepared by adopting the methods of chemical crosslinking, material compounding and freeze drying, the cost is low, the raw material sources are wide, the material can be repeatedly recycled and naturally degraded for many times, and the chitosan-based composite aerogel microbead heavy metal ion adsorption material is non-toxic and harmless to the environment, green and environment-friendly and is suitable for treating various heavy metal ion water pollutions.
Yet another prior art document, US11248107B2, disclosed a method for preparing an aerogel or a foam, the method comprising: forming a reaction mixture comprising a cellulose nanofibril gel, a first solvent, and one or more crosslinking agents under conditions sufficient to crosslink the gel; and contacting the crosslinked gel with a second solvent under conditions sufficient to dry the crosslinked gel, thereby forming an aerogel or foam.
However, above mentioned references and many other similar references have one or moreof the following shortcomings: (a) Low environment friendly; (b) Hazardous; (c) synthesis from nanocellulose from different origin sources; (d) use of nanoparticles containing chitosan and other materials from tobacco; (d) Costly reagent; and (e) Take longer duration in generating nanoparticle.
The present application addresses the above mentioned concerns and short comings with regard to providing a novel formulation for dyes degradation.

SUMMARY OF THE INVENTION
In the view of the foregoing disadvantages inherent in the known methods, compositions, and formulations for dyes degradation of wastewater now present in the prior art, the present invention provides an improved nanocomposite comprising SmO and g-C3N4. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new and improved synthesis method of nanocomposites of Samarium Oxide and graphite carbon nitride for dyes degradation which has all the advantages of the prior art and none of the disadvantages.
The main object of the present invention is to provide a nanocomposite for degrading dyes comprising of Graphite Carbon Nitride (g-C3N4) and Samarium Oxide (SmO) in varying ratios.
Another object of the present invention is to provide the nanocomposite for degrading dyes, wherein ratio of Samarium oxide (SmO) to graphite carbon nitride (g-C3N4) in the ratio varying from 1:1; 1:1.5 and 1:2.
Yet another object of the present invention is to provide the nanocomposite for degrading dyes, wherein said dyes can be anionic dyes, cationic dyes, and mixture thereof.
Yet another object of the present invention is to provide the nanocomposite for degrading dyes, wherein said dyes is selected from Rose Bengal, Xylenol Orange, Auramine O, and Crystal Violet, and mixed dye.
Yet another object of the present invention is to provide A preparation method of nanocomposite of SmO and g-C3N4 comprising the following steps: (i) A Preparation of graphite Carbon nitride (g-C3N4):
(a) Heating Urea in a crucible at 550 °C at a ramp rate of 5 °C in a furnace for 3 hours; and
(b) Grinding heated Urea from step (a) for producing said graphite carbon nitride (g-C3N4);
(ii) SmO nanoparticles were synthesized via the co-precipitation method:
(p) Dissolving Sm2O3 powder in distilled water;
(q) Adding NaOH to solution of step (p), which caused the Sm2O3 to undergo hydrolysis and create Sm(OH)3;
(r) Stirring and Adding ethanol for converting Sm(OH)3 to Samarium oxide (SmO);
(iii) Mixing graphite Carbon nitride (g-C3N4) and SmO nanoparticles:
(I) Doping different molar ratios of SmO in g-C3N4 nanoparticles at a fixed ratio 1:x (where x = 1, 1.5, and 2); and
(II) The mixture of step (I) was sonicated, dried at 60°C for 24 hours, and then calcined at 500°C for 2 hours to form the SmO/g-C3N4 nanocomposite.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
Fig. 1 shows synthesis route of SmO/g-C3N4 nanocomposites, according to an embodiment herein.
Fig. 2 depicts XRD pattern of SmO/g-C3N4 nanocomposites, according to an embodiment herein.
Fig. 3 depicts Fourier Transform InfraRed FTIR Spectrum of SmO nanocomposites, according to an embodiment herein.
Fig. 4 depicts SEM morphology of two nanomaterials (a) g-C3N4, (b) SmG-1.5 nanocomposite, according to an embodiment herein.
Fig. 5 depicts TEM images of (a) g-C3N4, (b) SmG-1.5 nanocomposite, (c) SAED pattern of SmG-1.5 nanocomposite, according to an embodiment herein.
Fig. 6 depicts (a) EDX pattern of SmG-1.5 nanocomposite; (b-e) Elemental mapping of SmG-1.5 nanocomposite, according to an embodiment herein.
Fig. 7 depicts (a) wide XPS spectra of SmG-1.5 composite and g-C3N4 ; XPS spectra of (b) Ce3d; (c) C1s (d) N1s and (e) O1s, according to an embodiment herein.
Fig. 8 depicts Photoluminescence PL spectra of prepared nanocomposites, according to an embodiment herein.
Fig. 9 depicts (a) UV DRS of g-C3N4, SmO, and SmG nanocomposites. (b) Tauc plot for a bandgap of g-C3N4, SmO, and SmG nanocomposites, according to an embodiment herein.
Fig. 10 depicts (a-e): UV-Vis absorbance spectra for RB dye, (f) Photocatalytic activity comparison (g) ln(C0/Ct) degradation kinetics, according to an embodiment herein.
Fig. 11 depicts UV-Vis absorbance spectra of nanocomposites for XO dye, (f) Photocatalytic activity comparison (g) ln(C0/Ct) degradation kinetics, according to an embodiment herein.
Fig. 12 graphs depicting effect of pH on Anionic, Cationic, and Mix dyes, according to an embodiment herein.
Fig. 13 depicts (a) Investigation of dye photocatalytic degradation of dyes using SmG-1.5 nanocomposite in recycling experiments, (b-f) comparative analysis of photocatalytic degradation over 5 cycles using SmG-1.5 nanocomposite, according to an embodiment herein.
Fig. 14 graphs depicting mechanism of dye degradation using prepared nanocomposites, according to an embodiment herein.
DETAILED DESCRIPTION OF THE INVENTION
In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that the embodiments may be combined, or that other embodiments may be utilized and that structural and logical changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.
References will now be made in detail to the exemplary embodiment of the present disclosure. Before describing the detailed embodiments that are in accordance with the present disclosure, it should be observed that the embodiments reside primarily in combinations arrangement of the system according to an embodiment herein and as exemplified in FIGs. 1 to 14.
Wastewater pollution due to dyes is a significant environmental issue globally. Dealing dye-containing wastewater into water bodies can harm aquatic life, human health, and the environment. Dyes are synthetic and natural organic compounds that can cause severe damage to the ecosystem by decreasing the amount of sunlight penetration, reducing dissolved oxygen levels, and altering water pH. Additionally, some dyes contain toxic heavy metals and carcinogenic substances that can threaten human health. Therefore, the treatment of dye-containing wastewater is necessary to prevent contamination and ensure the environment's sustainability (Sharma et al, 2021. Removal of organic dyes from wastewater using Eichhornia crassipes: a potential phytoremediation option. Environ. Sci. Pollut. Res. 28, 7116-7122. https://doi.org/10.1007/s11356-020-10940-8). Photocatalysis has been identified as a sustainable and efficient technique for degrading wastewater's organic pollutants, including dyes (Rattan Paul and Nehra, Graphitic carbon nitride: a sustainable photocatalyst for organic pollutant degradation and antibacterial applications. Environ. Sci. Pollut. Res. 28, 3888-3896. https://doi.org/10.1007/s11356-020-09432-6). Using photocatalysis is a promising approach to treating wastewater, especially for breaking down organic pollutants like dyes. Compared to conventional techniques, photocatalysis utilizes a photocatalyst and light energy to initiate the degradation mechanism resulting in more rapid and efficient treatment. Another advantage of photocatalysis is that it is environmentally safe and sustainable , as it does not require harmful substances or produce toxic byproducts.
Since its discovery, owing to its remarkable features, graphitic carbon nitride (g-C3N4) has gained considerable interest as a potential photocatalyst (Ouyang et al., Synthesis of a novel Z-scheme Ag/WO3/g-C3N4 nanophotocatalyst for degradation of oxytetracycline hydrochloride under visible light. Mater. Sci. Semicond. Process. 137. https://doi.org/10.1016/j.mssp.2021.106168). Because of a small bandgap of 2.7 eV, which allows it to absorb visible light, g-C3N4 is an excellent choice for photocatalysis (Bhoyar et al., Tailoring photoactivity of polymeric carbon nitride via donor-p-acceptor network. Appl. Catal. B Environ. 310, 121347. https://doi.org/10.1016/J.APCATB.2022.121347). However, g-C3N4 's inability to separate photo-generated electron-hole pairs limits its photocatalytic activity, which can result in electron-hole recombination and decreased efficiency (g-C3N4-based nanomaterials for visible light-driven photocatalysis. Catalysts 8, 74. https://doi.org/10.3390/catal8020074). The problem can be solved by increasing g-C3N4 's photocatalytic activity by doping it with metals or metal oxides (Metal-free four-in-one modification of g-C3N4 for superior photocatalytic CO2 reduction and H2 evolution. Chem. Eng. J. 430, 132853. https://doi.org/10.1016/J.CEJ.2021.132853).
Samarium, a rare earth element, is desirable in photocatalysis due to its remarkable electrical properties. Because of its narrow bandgap energy (Liu et al., Improved activity and significant SO2 tolerance of samarium modified CeO2-TiO2 catalyst for NO selective catalytic reduction with NH3. Appl. Catal. B Environ. 244, 671-683. https://doi.org/10.1016/J.APCATB.2018.12.001), Samarium (Sm) is chosen as the doping element for graphitic carbon nitride (g-C3N4), which improves the photocatalytic activity of g-C3N4 by increasing its light absorption (Rakibuddin and Kim, Samarium (III)-doped ZnO/graphitic-C3N4 composites for enhanced hydrogen generation from water under visible light photocatalysis. J. Alloys Compd. 832, 154887. https://doi.org/10.1016/j.jallcom.2020.154887). Samarium also has superb catalytic qualities that increase the chemical stability and endurance of g-C3N4 (Liu et al., 2021). Increased surface area and pore volume, improved charge separation efficiency, better light absorption, and increased reusability are all benefits of using samarium-doped g-C3N4 for photocatalysis. As a result, samarium-doped g-C3N4 offers a practical and affordable method for reducing organic pollutants in wastewater.
The present invention discloses a novel approach to synthesizing SmO/g-C3N4 nanocomposites for degrading organic dyes, including Rose Bengal, Xylenol Orange, Auramine O, and Crystal Violet, and mixed dye under visible light irradiation. The novel aspect of this study is the cost-effective and long-lasting dye degradation solution provided by the synthesis of SmO/g-C3N4 using a simple and effective method. This study employs a distinctive photocatalyst, SmO/g-C3N4, which displays improved photocatalytic activity and excellent reusability compared to previously published work (Jourshabani et al. Synthesis and characterization of novel Sm 2 O 3 /S-doped g-C 3 N 4 nanocomposites with enhanced photocatalytic activities under visible light irradiation. Appl. Surf. Sci. 427, 375-387. https://doi.org/10.1016/j.apsusc.2017.08.051; Li et al., Sm-doped mesoporous g-C3N4 as efficient catalyst for degradation of tylosin: Influencing factors and toxicity assessment. Appl. Surf. Sci. 517, 146212. https://doi.org/10.1016/j.apsusc.2020.146212; Rakibuddin and Kim, Samarium (III)-doped ZnO/graphitic-C3N4 composites for enhanced hydrogen generation from water under visible light photocatalysis. J. Alloys Compd. 832, 154887. https://doi.org/10.1016/j.jallcom.2020.154887). The findings indicate that SmO/g-C3N4 has much potential for real-world use in wastewater treatment to degrade organic dyes.
Synthesis of SmO/g-C3nN4 nanocomposites
Synthesis of g-C3N4
Urea is used as a precursor in a hydrothermal process to synthesize graphitic carbon nitride (g-C3N4) (Fig. 1a). 10 g of urea is first heated in a crucible at 550 °C at a ramp rate of 5 °C in a furnace for 3 hours. Using an agate mortar and pestle, the finished product of the synthesis is ground into a fine powder. This synthesis method produces g-C3N4, which has a high surface area and exceptional photocatalytic activity thanks to its highly porous and layered structure.
Synthesis of SmO nanoparticles
SmO nanoparticles were synthesized via the co-precipitation method (Fig. 1b). First, 20 mL of distilled water was used to dissolve 1 g of Sm2O3 powder. Next, 4 g of NaOH was added, which caused the Sm2O3 to undergo hydrolysis and create Sm(OH)3. The mixture was stirred until the Sm(OH)3 was evenly distributed and the NaOH was completely dissolved. The Sm(OH)3 underwent dehydration and formed SmO nanoparticles after 20 mL of ethanol was gradually added to the mixture while stirring continuously. For the SmO nanoparticles to ultimately precipitate, the solution was left to sit for a few hours or overnight. After being separated by centrifugation, the SmO nanoparticles underwent a series of ethanol washes to separate any remaining impurities. The sample was then dried in hot air oven to obtain SmO nanocomposites.
Mixing and Reacting of SmO and g-C3nN4 to form nanocomposites
In (Fig. 1c), SmO/g-C3N4 nanocomposites were created efficiently by doping different molar ratios of SmO in g-C3N4 nanoparticles at a fixed ratio 1:x (where x = 1, 1.5, and 2). The resulting mixture was then sonicated at room temperature for 2 hours to ensure uniform dispersion of the SmO nanoparticles in the g-C3N4 matrix. The mixture was sonicated, dried at 60°C for 24 hours, and then calcined at 500°C for 2 hours to form the SmO/g-C3N4 nanocomposite. This method enabled the controlled growth of SmO nanoparticles on the surface of g-C3N4, yielding a well-dispersed SmO/g-C3N4 nanocomposite. The nanocomposites were abbriviated as SmG-1, SmG-1.5, and SmG-2.

The SmO/g-C3N4 composite was characterized by several analytical techniques to investigate its structural, morphological, and optical properties. On a Bruker D8 diffractometer, X-ray diffraction (XRD) analysis was carried out using Cu-K radiation ( = 1.5418 ) at 40 kV and 40 mA. The data were collected in the 2? range of 10°-80° with a scanning rate of 0.02° s-1. Fourier transforms infrared (FTIR) spectroscopy was performed on a Perkin Elmer Spectrometer instrument in the 4000-400 cm-1 using the KBr pellet technique. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) was used to analyze the morphological characteristics of the samples. JSM 7900-F was used to acquire SEM images instrument at 1m, 2m resolution, and 10,000 magnification.TEM images (100-nm resolution ) were taken on a (TEM Talos F200X instrument operating at 200 kV. On a Thermo Scientific K-Alpha XPS instrument, X-ray photoelectron spectroscopy (XPS) was performed with monochromatic Al-Ka X-rays (1486.6 eV). On a Shimadzu UV-2600 I spectrophotometer, ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS) measurements were made in the 200-800 nm range. The optical bandgap of the composite was calculated using the Taucs Equation.
Photocatalytic Activity
The photocatalytic activity of the synthesized SmO/g-C3N4 nanocomposites was evaluated using five different dyes, including anionic dyes (such as Rose Bengal and Xylenol Orange), cationic dye (including Auramine O and Crystal Violet) and Mix dyes. The degradation experiments were performed by adding 10 mg of the nanocomposites to a 100 mL aqueous dye solution with an initial ten mg/L concentration. The suspension was irradiated under a 400 W Xe lamp for 120 min, with a constant stirring rate of 600 rpm. The following equation was used to calculate the degradation efficiency:
Degradation efficiency (%) = [(C0 - Ct)/C0] × 100 - Eq.1
Where the dye's initial and final concentrations are denoted by the letters C0 and Ct, respectively. The absorption spectra of the dyes were recorded at regular intervals using a UV-Vis spectrophotometer to monitor the degradation process. The experimental setup was carefully designed to ensure the irradiation was uniform throughout the solution. Reaction conditions were optimized to maximize the dye degradation rate for each dye.
Results and Discussion
XRD data
The XRD pattern of g-C3N4 (Figure 2) displays distinct peaks at 13.2° and 27.4°, which correspond to the (100) and (111) planes (002). These peaks demonstrate that g-C3N4 has a multilayer hexagonal structure with a preferred orientation along the x-axis, perpendicular to the carbon and nitrogen atom layers. The XRD peaks of SmO nanoparticles observed at 20°, 28°, 30°, 32°, 41°, 46°, 51°, 58°, and 60° for SmO nanocomposites correspond to the (211), (222), (400), (411), (332), (134), (440), (622), and (444) planes, respectively. These peaks confirm the crystalline nature of the nanoparticles and suggest the presence of a cubic structure. These results confirm the presence of both precursors in the nanocomposite. The XRD analysis of SmO/g-C3N4 nanocomposite indicates successful nanocomposite synthesis by showing the characteristic peaks of both precursors g-C3N4 and SmO.
FTIR Data Analysis
FTIR (Fourier transform infrared) spectra of SmO nanoparticles and g-C3N4 (graphitic carbon nitride) were analyzed to study the SmO/g-C3N4 nanocomposites. In the FTIR spectrum (Fig:3) of the SmO nanoparticle, a sharp absorption band was observed at 3418 cm-1, corresponding to the tensile vibration of the O-H group. The peak observed at 788 cm-1 confirms the existence of an Sm-O bond in the crystal (Jiang et al., 2020). The FTIR spectrum of g-C3N4 showed characteristic peaks at 1640 cm^-1, attributed to the stretching vibration of C=N bonds. The peaks observed at 1560, 1400, and 1310 cm-1 are associated with the stretching vibrations of aromatic C=C bonds. The peaks observed at 1230 and 807 cm^-1 correspond to the bending vibrations of C-N bonds and the out-of-plane deformation of C-H bonds, respectively (Shoran et al., 2023). The SmG nanocomposites showed characteristic peaks of both precursors, confirming their successful synthesis. The FTIR analysis revealed the Sm-O bond and crystalline water in the SmO nanoparticle. At the same time, g-C3N4 showed characteristic peaks associated with the stretching vibrations of C=N and C=C bonds.
SEM Analysis
Scanning electron microscopy (SEM) is useful for studying material surface morphology. The SEM analysis of pure g-C3N4 in Fig.4a revealed a lamellar structure aggregation at 10,000x magnification due to the rapid breakdown of nitrates during heating.
SEM analysis of SmO nanoparticles in Figure 4b revealed only a minor amount of agglomeration, indicating the co-precipitation method's efficiency in synthesizing well-dispersed nanoparticles. The SmG-.5 nanocomposite in Figure 4c had a one-of-a-kind structure with small, irregularly shaped SmO particles distributed on the surface of the g-C3N4 nanoparticle.
TEM Analysis
In Figure 5a, TEM analysis of pure g-C3N4 revealed a layering structure with many stacking layers, typically of 2D layered material. The TEM images of SmG-1.5 nanocomposite in Figure 5b revealed a rough texture, which should improve its catalytic activity. The SmG-1.5 composite also had small, irregularly shaped SmO nanoparticles wrapped around the surface of the g-C3N4 layer giving it a distinct morphology. The selected area electron diffraction (SAED) pattern of the SmG-1.5 composites revealed bright rings of spots in Fig.5c, indicating the crystalline nature and reduced size of SmO nanoparticles. Due to the g-C3N4 matrix, isolated dots were also observed in the pattern. The image suggests that SmO nanoparticles were successfully dispersed on the surface of g-C3N4, which could lead to increased photocatalytic activity. Because of this morphology, it can provide more active sites for dye adsorption and degradation, making it an efficient photocatalyst.
EDX Analysis
The elemental composition of SmO/g-C3N4 nanocomposites was determined using energy-dispersive X-ray spectroscopy (EDX) analysis (Fig.6). The weight percentage and atomic percentage of carbon (13.07% and 46.53%), nitrogen (10.55% and 32.21%), and Sm (69.50% and 19.77%,) was determined. The EDX data confirm the presence of carbon, nitrogen, and Samarium in the SmO/g-C3N4 nanocomposite. The high percentage of Samarium indicates that the SmO nanoparticles are well dispersed in the g-C3N4 matrix. The atomic percentages of carbon and nitrogen indicate that g-C3N4 is present in the composite. X-ray diffraction (XRD) analysis also confirmed the presence of these elements. Elemental mapping was also carried out to investigate the spatial distribution of the elements in the nanocomposite. The results showed that carbon and nitrogen were uniformly distributed throughout the composite. At the same time, Samarium was mainly concentrated in specific regions, indicating that the SmO nanoparticles were dispersed in the g-C3N4 matrix with some aggregation.
XPS Analysis
A robust method for examining the elemental makeup and chemical bonds of various materials is X-ray photoelectron spectroscopy (XPS). The C1s, N1s, and O1s spectra of g-C3N4 and SmO composites were analyzed using XPS. In Fig.7b, the C1s spectrum of g-C3N4 displayed two chemical states of the carbon element. The peaks at 288.1 eV are attributed to sp2 hybrid C-(C=N), and 285.2 eV peaks are due to C-(N)3, respectively. In Fig.7c, the N1s spectrum of g-C3N4 could be fitted to two peaks, 401.0 eV and 398.7 eV. The peak at 401.0 eV was assigned to the amino functional group (N-H), mainly derived from the incomplete polymerization of urea. The peaks at 398.7 eV were identified as sp2 hybridization of N, corresponding to N of the N=C bond. In Fig.7d, the O1s spectrum of g-C3N4 displayed one prominent peak at 532.3 eV, which is attributed to the oxygen atoms bonded to carbon or nitrogen atoms in the lattice structure of the material. The C1s, N1s, and O1s spectra of the SmO composites showed similar peaks to those observed in g-C3N4. As shown in Fig. 7d, the interaction of spin orbits caused the Sm 3d high-resolution spectrum to split into two peaks at 1082.9 eV (Sm 3d 5/2) and 1105.1 eV (Sm 3d 3/2). The two dipole peaks belong to Sm3+ ions in Sm2O3, indicating no other valence state of Sm in the sample, and the doped Sm exists in the Sm (III) state. Comparing the broad spectrum of SmO and g-C3N4 composites (Fig.7a), SmO showed additional peaks corresponding to Sm3d and O1s. At the same time, g-C3N4 displayed additional peaks in the C1s and N1s regions. These results indicate that SmO nanoparticles have been successfully dispersed on the surface of g-C3N4, and the composites are formed through chemical bonding between the two materials.
Photoluminescence
Photoluminescence (PL) is the phenomenon in which material emits light after absorbing light of a different wavelength. This dimension of light is caused by the recombination of electrons and holes that are created when the material absorbs light. The wavelength of the emitted light is determined by the energy difference between the energy levels of electrons and holes. In the case of g-C3N4, the main peak in the PL spectrum is around 460 nm (Fig.8). This peak corresponds to the radiative recombination of electron-hole pairs that are created when g-C3N4 Absorbs light in the visible region of the spectrum. The PL spectrum of SmO nanoparticles typically shows two main peaks one at 440 nm, and another at 490 nm. the peak at 440 nm is attributed to the radiative recombination of electron-hole pairs that are created in the SmO lattice. the peak at 490 nm is caused by the transition between defective states in the SmO lattice. these emission peaks confirm the presence of Sm3+ ions in the SmO composite and their contribution to photoluminescence behavior. The decrease in peak intensity of SmO/g-C3N4 ¬nanocomposites in the order SmG-2, SmG-1.5, and SmG-1 can be attributed to the increased surface area to volume ratio of nanocomposites. The observed decrease in the PL intensity suggests enhanced photocatalytic activity and improved efficiency in the nanocomposite system.
UV-DRS
The UV-Vis DRS spectra of SmO/g-C3N4 nanocomposites were analyzed to investigate their optical properties. The absorption peaks observed at various wavelengths in these Spectra indicated the presence of distinct energy levels within the materials (Figure 9). The energy bandgap is a crucial parameter for investigating the electrical properties of a material that can be determined using the Tauc relation
ahv =A(h?-Eg)n -Eq 2
Equation two describes the relationship between the absorption coefficient (a), the photon energy (h?), the optical band gap (h?), and a constant value (A). The specific value of the index (n) depends on the form of transition, with the values of ½,3/2,2.0, and 3.0 corresponding to directly permitted, indirectly permitted, and end prohibited transition, respectively. Figure 9b depicts the relationship between absorbance and photon energy for the manufactured composites, with the suitable match observed at n-2, indicating the existence of a direct allowed band gap. (Rahimi-Nasrabadi et al., 2017). g-C3N4 has an absorption edge at 343nm and 2.79 eV. At 380 nm, AmO exhibited an absorption peak with a 2.63 eV energy. As the quantity of SmO added to g-C3N4 increased, the absorption shifted to longer wavelengths, resulting in a decrease in energy. SmG-1 exhibited an absorption maximum at 410 nm with a 2.48 eV energy. SmG-1.5 exhibited an absorption peak with an energy of 2.18 eV at 456 nm.SmG-2 had a maximum energy of 2.33 eV at 426 nm. The decrease in energy levels as SmO concentration increases suggests that SmO/g-C3N4 nanocomposites have a narrower bandgap, which could improve their photocatalytic activity. The lower wavelength and bandgap observed in SmG-1.5 compared to SmG-2, despite a higher molar concentration of SmO, can be attributed to various factors, including enhanced interaction and integration of SmO within the g-C3N4 matrix, potential modifications in the electronic structure and energy levels, and the size and distribution of SmO nanoparticles. The increased absorption region of SmG-1.5 suggests a higher production of electron-hole (e- h+) pairs, which can enhance its photocatalytic activity.
Photocatalytic Activity
The photocatalytic activity of SmO/g-C3N4 nanocomposites was evaluated by testing their efficiency in visible light irradiation for 120 minutes and determining the degradation of anionic, cationic dyes, and Mix dyes. Rose Bengal is an anionic dye used in the textile industry and as a biological stain. The order of photocatalytic degradation of Rose Bengal dye was found to be SMG-1.5 (84.7%) > SMG-2 (76.5%) > SMG-1 (70.2%) > g-C3N4 (65%) > SMO(48.8%). The results indicate that SmO/g-C3N4 composites are highly efficient photocatalysts for degrading Rose Bengal dye (Fig.10 a-e). SMG-1.5 exhibited the highest degradation efficiency, which can be attributed to the synergistic effect of SmO and g-C3N4. SmO nanoparticles acted as electron acceptors, and g-C3N4 acted as an electron donor, which led to efficient charge separation and enhanced photocatalytic activity.
Xylenol Orange is an anionic dye commonly used in analytical chemistry as an indicator for detecting transition metals. The order of photocatalytic degradation of Xylenol Orange dye was found to be SMG-1.5 (75.3%) > SMG-2 (62.2%) > SMG-1 (57.3%) > g-C3N4 (41.6%) > SMO(2.4%). It can be observed that the SmO/g-C3N4 composites showed much better photocatalytic activity than their respective precursors (Fig.11 a-e). Among the composites, SMG-1.5 showed the highest degradation efficiency of Xylenol Orange dye. This can be attributed to the smaller size of the SmO nanoparticles and increased interfacial contact with g-C3N4, leading to higher surface area and more active sites for photocatalytic activity.
Auramine O is a cationic dye widely used as a textile dye in the pharmaceutical business. The order of photocatalytic degradation of Auramine O dye was found to be SMG-1.5 (82.2%) > SMG-2 (76.6%) > SMG-1 (72.7%) > g-C3N4 (46.4%) > SMO(27.3%). The findings demonstrated that compared to their respective precursors, SmO/g-C3N4 composites had much higher photocatalytic activity (data not shown). SMG-1.5, among the composites, demonstrated the most incredible Auramine O dye degradation efficiency. The synergistic impact of SmO and g-C3N4, which resulted in effective charge separation and increased photocatalytic activity, is responsible for the high efficiency of SMG-1.5.
A cationic dye called Crystal Violet is employed in the textile sector and as a histology stain. According to research, the Crystal Violet dye degrades photo catalytically in the following order: SMG-1.5 (72.3%) > SMG-2 (69.7%)> SMG-1 (64.8%)> g-C3N4 (41.6%)> SMO (27.1%). The findings demonstrate that the photocatalytic activity of SmO/g-C3N4 nanocomposites was superior to that of their respective precursors. SMG-1.5 showed the best efficiency for Crystal Violet dye degradation among the composites. SMG-1.5 has a more significant surface area and more active sites for photocatalytic activity as a result of the tiny size of the SmO nanoparticles and improved interfacial contact with g-C3N4.
The mix dye is a mixture of one ratio one mixture of anionic and cationic dyes. According to the research, the degradation of mixed dyes is in the following order: SMG-1.5 (80%) > SMG-2 (73.3%)> SMG-1 (68.7%)> g-C3N4 (53.3%)> SMO (33.1%). These results highlight the synergistic effect of SmO and GCN in enhancing the photocatalytic activity, with SmG-1.5 demonstrating the highest degradation efficiency.
Table 1 shows the degradation efficiency of all nanocomposites. Overall, the findings indicate that the SmO/g-C3N4 composites exceed their precursors in photocatalytic activity for all five dyes examined. This might be explained by the composites' enhanced charge transfer effectiveness and greater surface area, which enhance charge carrier production and separation. Among the several SmO/g-C3N4 composites, SmG-1.5 had the maximum photocatalytic degradation efficiency for all five dyes. The SmG-2 composite showed decreased photocatalytic activity despite having a higher molar concentration of SmO than SmG-1.5. This might be caused by the agglomeration of SmO particles under heavier loading, which reduces surface area and prevents efficient charge transfer. As a result, an ideal SmO loading is necessary to achieve the most excellent photocatalytic activity in SmO/g-C3N4 composites. Table 2 compares the degradation efficiency of SmO/g-C3N4 composites with previously published work.
Table 1: Degradation efficiency of precursors and nanocomposites

Table 2: Comparative analysis of previously published dye degradation studies


VanDao, 2018 - Ionic liquid-assisted preparation of Ag-CeO2 nanocomposites and their improved photocatalytic activity. Mater. Des. 159, 186-194. https://doi.org/10.1016/j.matdes.2018.08.042
Shoran, 2023 - Visible light enhanced photocatalytic degradation of organic pollutants with SiO2/g-C3N4 nanocomposite for environmental applications. Environ. Sci. Pollut. Res. https://doi.org/10.1007/s11356-022-24837-1
Rattan Paul, 2021a - Graphitic carbon nitride: a sustainable photocatalyst for organic pollutant degradation and antibacterial applications. Environ. Sci. Pollut. Res. 28, 3888-3896. https://doi.org/10.1007/s11356-020-09432-6
Iliev, 2004 - Photooxidation of xylenol orange in the presence of palladium-modified TiO2 catalysts. Catal. Commun. 5, 759-763. https://doi.org/10.1016/j.catcom.2004.09.005
Murugadoss, 2021 - Silver decorated CeO2 nanoparticles for rapid photocatalytic degradation of textile rose bengal dye. Sci. Rep. 11, 1-13. https://doi.org/10.1038/s41598-020-79993-6
Shoran, 2022 - Photocatalytic dye degradation and antibacterial activities of CeO2/g-C3N4 nanomaterials for environmental applications. Environ. Sci. Pollut. Res. https://doi.org/10.1007/S11356-022-23815-X
Rattan Paul and Nehra, 2021b - Graphitic carbon nitride: a sustainable photocatalyst for organic pollutant degradation and antibacterial applications. Environ. Sci. Pollut. Res. 28, 3888-3896. https://doi.org/10.1007/s11356-020-09432-6

The apparent rate constant (ARC) is an important parameter used to evaluate the photocatalytic efficiency of nanocomposites. Langmuir-Hinshelwood's pseudo-first-order kinetic Equation can model the photocatalytic degradation of dyes,
ln (C0/Ct) = Kapp t - Eq- 3
where the rate constant (Kapp) is determined by the initial concentration of the dye (C0) and its concentration at a specific time (Ct). The ARC values for different nanocomposites were measured for five dyes: auramine O, crystal violet, rose bengal, xylenol orange, and Mix dyes, as shown in Fig. 10(f -g), 11(f -g), and presented in Table 3.
Table 3: Apparent rate constant (K min-1) for synthesized nanocomposites


For auramine O dye, the highest ARC value was observed in the following order SmG-1.5 (0.01963 K) > SmG-2 (0.01323 K min-1) > SmG-1 (0.01054 K min-1) > SmO (0.00274 K min-1) > g-C3N4 (0.0068 K min-1). These results suggest that the SmO/g-C3N4 nanocomposites have higher photocatalytic activity than the individual SmO or g-C3N4 precursors, with the SmG-1.5 nanocomposite being the most efficient. For crystal violet dye, the highest ARC value was observed in the following order SmG-1.5 (0.00983 K min-1) > SmG-2 (0.00951 K min-1) >SmG-1 (0.00856 K min-1)> SmO (0.00243 K min-1)> g-C3N4 (0.00575 K min-1). These results suggest that the SmO/g-C3N4 nanocomposites have higher photocatalytic activity than the individual SmO or g-C3N4 precursors, with the SmG-1.5 nanocomposite being the most efficient. The ARC for rose bengal dye for the nanocomposite was observed in the order: SmG-1.5 (0.01462)> SmG-2 (0.01165 K min-1)> SmG-1 (0.00966 K min-1) > g-C3N4 (0.00959 K min-1) > SmO (0.00571 K min-1).
According to these findings, SmO/g-C3N4 nanocomposites, notably the SmG-1.5 nanocomposite, show better photocatalytic activity than SmO or g-C3N4 precursors alone. For the xylenol orange dye, the highest ARC value was observed in the following order SmG-1.5 (0.01125 K min-1)>SmG-2 (0.00811 K min-1)>SmG-1 (0.00706 K min-1)>SmO (0.0034 K min-1), g-C3N4 (0.00443 K min-1). These results show that SmO/g-C3N4 nanocomposites (SmG-1.5) have higher photocatalytic activity than individual SmO or g-C3N4 precursors.
For Mix dyes, the highest ARC value was observed in the following order SmG-1.5 (0.01132 K min-1) > SmG-2 (0.01039 K min-1) > SmG-1 (0.00886 K min-1) > g-C3N4 (0.00459 K min-1) > SmO (0.00338K min-1). According to these findings, SmO/g-C3N4 nanocomposites show better photocatalytic activity than individual SmO or g-C3N4 precursors, with the SmG-1.5 nanocomposite being the most efficient.
SmO/ g-C3N4 nanocomposites displayed stronger photocatalytic activity than individual SmO or g-C3N4 precursors for all five dyes evaluated. The SmG-1.5 Nanocomposite exhibited the greatest ARC value for all five dyes, indicating that it is the most efficient nanocomposite for photocatalytic degradation of these dyes.
3.11. Statistical Analysis
In general, a high R2 Means that the experimental data and the theoretical model fit well together and that the model is a good fit for the data. The high values of R2 obtained from the first-order kinetic model (as presented in Table 4 ) demonstrate the efficacy of the SmO/ g-C3N4 nanocomposites as photocatalysts in degrading dyes (Fig.10g, 11g, 12g, 13g, 14g). The R2 Value analysis of different nanocomposites for five dyes showed that the R2 value for SmO-1.5 nanocomposite was not the highest for all dyes, but it still showed a good correlation between the data points, suggesting a good fit. Because SmO/g-C3N4 nanocomposite has a high R2 value for these dyes, it may be a good option for photocatalytic applications that degrade these dyes. Thus, the SmG-1.5 nanocomposite Showed an excellent fit for all dyes studied, indicating its potential for various photocatalytic applications.
Table 4: R2 Value for prepared nanocomposites

Effect of pH
SmG-1.5 nanocomposite was used to study the degradation of anionic, cationic, and mixed dyes at various pH levels (Fig.1). the results show that SmG-1.5 nanocomposite degrades anionic dyes like rose Bengal and xylenol orange faster at lower pH levels. Rose Bengal and xylenol orange were degraded the fastest at pH 4, with 84.7% and 75.3% degradation rates, respectively. Cationic dyes, such as crystal Violet and auramine O, degraded faster at basic pH levels. At pH 10 the highest degradation rates for crystal Violet and auramine O were observed, at 72.3% and 82.2%, respectively. Mix dyes showed maximum degradation at pH 6 with an 80% degradation rate. Because of the high H+ concentration, cationic dyes bind strongly to the nanocomposite at lower pH values. Anionic dyes, on the other hand, have weaker interactions due to H+ ion shielding. Because of the presence of OH- ions, anionic dyes have stronger interactions with the nanocomposite at higher pH values, whereas cationic dyes have weaker interactions due to OH- ion shielding. Fig. 12 depicts Effect of pH on Anionic, Cationic, and Mix dyes.
Table 5: Photocatalytic Degradation efficiency of SmG-1.5 composite at various pH conditions.

3.13. Effect of Catalyst Loading
Table 6 below shows the result of an experiment to determine the effect of catalyst concentration on the photocatalytic activity of SmG-1.5 nanocomposite. The degradation percent of rose Bengal, xylenol orange, Auramine O, Crystal Violet, and mix dyes were measured at various catalyst concentrations and pH levels. The results show a significant relationship between catalyst concentration and degradation efficiency. The highest degradation percentages were observed up to a concentration of 0.005gm/100 ml, indicating improved photocatalytic activity. This improvement is due to more active sites on the catalyst surface, facilitating the photocatalytic process. However, the degradation percentage decreased slightly at the 0.007gm/100ml concentration. This decrease can be attributed to light scattering, caused by an excess of catalyst, which prevent light from efficiently interacting with dye molecules. As a result, exceeding the optimal catalyst concentration reduces photo activity degradation efficiency.
Table 6: Degradation efficiency of photocatalysts at different concentrations

3.14. Reusability-
The study also examined the recyclability and reusability of the SmO/g-C3N4 nanocomposite for the degradation of the five dyes (Fig. 16a). The results indicated that the nanocomposite could be used for up to five cycles while maintaining high photocatalytic activity. Specifically, for Rose bengal dye, the degradation efficiency of nanocomposite remained relatively stable over 5 cycles, with a slight decrease from 96.8% to 88.4%. Similarly, the nanocomposite showed stable degradation efficiency over 5 cycles for Xylenol Orange, slightly decreasing from 91.5% to 85.2%. Auramine O's degradation efficiency decreased from it is 86.6 % to 59.7%
Moreover, the C/Co values for each dye were consistent with the previous studies, indicating that the nanocomposite maintained its high effectiveness in the long run (Fig.13 b-f). These results suggest that SmO/g-C3N4 nanocomposite is highly effective, recyclable, and reusable for the photocatalytic degradation of different types of dyes, making it a promising candidate for environmental remediation applications.
Mechanism
The photocatalytic degradation mechanism of the SmO/g-C3N4 composite involves the excitation of the valence band (VB) electrons of g-C3N4 to the conduction band (CB) under UV light (Fig. 14). This results in the generation of electron-hole pairs that migrate to the surface of the composite. The SmO nanoparticles act as electron acceptors, which trap the electrons from the CB of g-C3N4, producing superoxide radicals (•O2-) Eq.-5
O2 + e- ? •O2- Eq.-5
The highly reactive superoxide radicals can directly react with the dye molecules, leading to their degradation. Additionally, the holes generated in the VB of g-C3N4 can react with water molecules to produce hydroxyl radicals (•OH), which are also highly reactive and contribute to the degradation of the dyes Eq.-6.
H2O + h VB+ ? •OH + H+ Eq.-5
Overall, the SmO/g-C3N4 composite's photocatalytic degradation mechanism involves the generation of superoxide and hydroxyl radicals, which react with dye molecules to degrade them. The high photocatalytic activity of the composite for various dyes makes it a promising candidate for environmental remediation applications.
The facile synthesis of SmO/g-C3N4 nanocomposites using the co-precipitation method has been demonstrated in this study. The characterization tests of the prepared nanocomposites, including XRD, SEM, TEM, and XPS, revealed their successful formation and proper morphology. The results of the photocatalytic degradation of five dyes, namely Auramine O, Xylenol Orange, Crystal Violet, Rose Bengal, and Mix dyes using SmO-1.5 nanocomposite as the photocatalyst, showed excellent degradation efficiency, with degradation rates ranging from 72.3% to 84.7% and ARC values ranging from 0.00706 to 0.01054 K min-1. The highest degradation efficiency was observed for Rose Bengal, followed by Auramine O, Mix dyes, Xylenol Orange, and Crystal Violet. The superior photocatalytic activity of SmO-1.5 nanocomposite can be attributed to the efficient separation of photo-generated electron-hole pairs due to the formation of junctions between SmO and g-C3N4. The high Apparent rate constant values indicated that the nanocomposite could rapidly degrade the dyes when exposed to UV light. The pH-dependent degradation studies showed that the degradation efficiency of anionic dyes was higher at low pH values, while cationic dyes showed better degradation at high pH values. The recycling tests of the SmO-1.5 nanocomposite demonstrated its stability and reusability for up to 5 cycles.
In conclusion, the SmO-1.5 nanocomposite prepared via the co-precipitation method showed excellent photocatalytic activity for degrading dyes under UV irradiation. The superior photocatalytic performance of SmO-1.5 can be attributed to its morphology and the efficient separation of photo-generated electron-hole pairs. These results suggest that the SmO/g-C3N4 nanocomposite has excellent potential as a future photocatalyst for the degradation of various organic pollutants.
It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-discussed embodiments may be used in combination with each other. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description.
The benefits and advantages which may be provided by the present invention have been described above with regard to specific embodiments. These benefits and advantages, and any elements or limitations that may cause them to occur or to become more pronounced are not to be construed as critical, required, or essential features of any or all of the embodiments.
While the present invention has been described with reference to particular embodiments, it should be understood that the embodiments are illustrative and that the scope of the invention is not limited to these embodiments. Many variations, modifications, additions and improvements to the embodiments described above are possible. It is contemplated that these variations, modifications, additions and improvements fall within the scope of the invention.
, Claims:We Claim:
1. A nanocomposite for degrading dyes comprising of Graphite Carbon Nitride (g-C3N4) and Samarium Oxide (SmO) in varying ratios.

2. The nanocomposite for degrading dyes as claimed in claim 1, wherein ratio of Samarium oxide (SmO) to graphite carbon nitride (g-C3N4) in the ratio varying from 1:1; 1:1.5 and 1:2.

3. The nanocomposite for degrading dyes as claimed in claim 1, wherein said dyes can be anionic dyes, cationic dyes, and mixture thereof.

4. The nanocomposite for degrading dyes as claimed in claim 1, wherein said dyes is selected from Rose Bengal, Xylenol Orange, Auramine O, and Crystal Violet, and mixed dye.

5. A preparation method of nanocomposite comprising the following steps:
(i) A Preparation of graphite Carbon nitride (g-C3N4):
(a) Heating Urea in a crucible at 550 °C at a ramp rate of 5 °C in a furnace for 3 hours; and
(b) Grinding heated Urea from step (a) for producing said graphite carbon nitride (g-C3N4);
(ii) SmO nanoparticles were synthesized via the co-precipitation method:
(p) Dissolving Sm2O3 powder in distilled water;
(q) Adding NaOH to solution of step (p), which caused the Sm2O3 to undergo hydrolysis and create Sm(OH)3;
(r) Stirring and Adding ethanol for converting Sm(OH)3 to Samarium oxide (SmO);
(iii) Mixing graphite Carbon nitride (g-C3N4) and SmO nanoparticles:
(I) Doping different molar ratios of SmO in g-C3N4 nanoparticles at a fixed ratio 1:x (where x = 1, 1.5, and 2); and
(II) The mixture of step (I) was sonicated, dried at 60°C for 24 hours, and then calcined at 500°C for 2 hours to form the SmO/g-C3N4 nanocomposite.

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