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Titanium dioxide nanoparticles are used in various applications, including environmental photocatalysis, solar cells and memory devices. In this study, we present the photodegradation of Rhodamine 6G and phenol red, employing heterogeneous photocatalytic process under solar irradiation. The experiments were carried out to study the effects of vario...
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Precious metals doped anatase titanium dioxide nanoparticles are used in various applications including environmental photocatalysis and solar cells. In this work we present the synthesis of Au- doped and Pt-doped TiO2 nanoparticles employing sol-gel methodology. The doping procedures based on reduction by UV photodeposition. The morphology, compos...
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... Even though the permutation score for the pH (PS = 0.98) was lower in comparison to the other input variables. The pH presents importance for the prediction of the m/z by the ANN model due to its influence in the charge of the active sites for photodegradation and protonation of the Rh6G dye [85]. ...
... The DNA capping enhances nanoparticle stability and facilitates controlled self-assembly, promoting conditions for efficient lasing. This technology has potential implications for compact, tunable, and highly customizable laser sources in fields like sensing, imaging, and communications [18,19]. ...
Deoxyribonucleic acid (DNA) capped silver nanoparticles are exceptional nanomaterials, featuring precise size and shape control enabled by DNA as a capping agent. DNA stabilizes these nanoparticles’ role leading to uniform structures for diverse applications. These nanoparticles are excellent in photonics and medical applications, enhancing fluorescence and medical imaging. In this study, we explore the multifaceted applications of DNA-capped silver nanoparticles, delving into their optical, photocatalytic, antibacterial, cytotoxic, and bioimaging properties. Employing UV–visible absorption spectroscopy and scanning electron microscopy, we provide an analysis of confirmation of silver nanoparticles. The investigation demonstrates substantial photocatalytic efficacy, photodegradation of methylene blue is higher than rhodamine 6G. The presence of silver nanoparticles enhances the fluorescence of rhodamine 6G doped sol–gel glasses. Furthermore, our findings illustrate significant antibacterial effects, encompassing both Gram-positive and Gram-negative bacteria, with DNA-capped silver nanoparticles exhibiting antibacterial activity. Cytotoxicity assessments on HeLa cells reveal concentration-dependent effects, with an LC50 value of 47 µL. Additionally, the in vitro experiments with HeLa cells suggest the promising utility of DNA-capped silver nanoparticles for bioimaging applications. This comprehensive analysis highlights the multifunctionality and potential of DNA-capped silver nanoparticles, offering promising avenues for further exploration and innovation within various scientific domains, particularly in the realm of nanomaterial research.
... CeO 2 is a n-type semiconductor metal oxide, it has limited properties like TiO 2 , e.g. cheap, photo stability, chemical inactivity and non-toxicity [12][13][14]. The conversion of Ce 4+ to Ce 3+ plays a crucial role in the performance of ceria-based materials. ...
Rare-earth doped cerium oxide nanostructures have garnered significant attention among researchers due to
their exceptional optical, magnetic and catalytic properties. In this work, Gd-doped CeO2 nanoparticles have
been developed by a cost-effective and facile chemical synthesis followed by calcination process. Raman and
XRD analysis confirm that single crystalline phase with a cubic fluorite unit cell is formed. XPS reveals the ex
istence of mixed valence states (Ce3+ and Ce4+). These mixed valence states contribute to formation of new
networks, such as Ce3+-O-Ce4+, Gd3+-O-Ce4+, and Ce3+-O-Ce3+.The absorption spectra of Gd3+ doped CeO2 nanoparticles shifted red related to pure CeO2 nanoparticles. It has been found that 8 % Gd showed highest magnetic characteristics while 6 % Gd shows highest photocatalytic activity towards degradation of rose bengal dye under UV light that may be attributed to the increase in interplanar distance, fast electron transfer, better electron–hole pair separation, and large surface area.
... The UV-vis-NIR spectra of phenol red dye in different pH media are presented in figure 7. Typical UV-Vis spectra of phenol red in natural water (pH= 7) shows three absorption bands which are located at 263, 431, and 570 nm. The band located at 263 nm is assigned to benzoic ring while the main two visible region bands which are located at 431 and 570 nm, attributed to the chromophoric structure [40]. Actually the molecular structure of some pollutant agents includes phenol red dye changes with the pH of the medium. ...
... Therefore, pH changes can influence the adsorption of phenol red dye molecules onto the ZnS-rGO surfaces. The evolution of the molecular structure of phenol red dye with pH of the solution was reported by Asiri et al [40] and Tamura and Maeda [41]. ...
The photocatalytic properties of reduced graphene oxide decorated ZnS nanocomposite was employed for photodegradation of phenol red as a chemical agent in water. ZnS nanocomposite was synthesized by hydrothermal method. Reduced graphene oxide decorated ZnS nanocomposite was produced by pulsed laser ablation of graphite bulk in the solution of ZnS nanocomposite. Variety of spectroscopic and imaging diagnostics including X-ray diffraction (XRD), UV-Vis absorption spectroscopy, transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were used to characterize the synthesized nanostructures. Water treatment was carried out in a closed handmade reactor. The concentration of the phenol red pollutant as the chemical agent, was extracted from the absorption spectra of treated water. Dependence of the behaviors of phenol red dye on the pH of the medium was studied in detail. Effects of UV radiation intensity, treatment time, pH of the polluted water, and aging on the efficiency of the treatment were investigated. Results show that even in the dark condition rGO-ZnS nanocomposite is an effective material to remove phenol red pollutant from water. The highest efficiency of treatment after 120 minutes was achieved in neutral pH water. Furthermore, after 7 days, with nanostructures and without UV radiation, the removal process in the polluted water was continued.
... rGO has a similar, though thinner, sheet-like morphology that aggregates randomly with distinct edges, wrinkled surfaces, and folds (Shalaby et al., 2015). N-TiO 2 appeared spherical in shape (Asiri et al., 2011). Small spherical particles can be seen adhering irregularly and non-homogenously to the subjacent surface. ...
This work provides a first-time comparative study examining the photocatalytic activity of functionalized TiO2-based composites to eliminate naphthol blue in Batik wastewater. Reduced graphene oxide (RGO) was synthesized by oxidizing solid graphite using the Hummers' method followed by sonication and reduction. N-doped TiO2 (N-TiO2) was synthesized from titanium tetrachloride (TiCl4) and urea (CH₄N₂O) precursors by the sol-gel method. N-TiO2 modified RGO (RGO/NT) was synthesized using a hydrothermal method from N-TiO2 and RGO. Prepared TiO2-based composites and commercial TiO2, for comparison were characterized using Fourier transform infrared spectrometer (FTIR), X-Ray diffractometer (XRD), scanning electron microscope-energy dispersive X-ray (SEM-EDX), and UV-Vis diffuse reflectance spectrometer (UV-Vis DRS). FTIR characterization indicated Ti-N bonding in N-TiO2 and RGO/NT. XRD patterns showed that commercial TiO2 had a rutile phase, while N-TiO2 and RGO/NT had an anatase phase with crystal sizes of 30.09, 16.28, and 12.02 nm, respectively. SEM results displayed the presence of small and glossy white N-TiO2 dispersed on the surface of RGO. Characterization using UV-Vis DRS showed that the band gap energy values for TiO2, N-TiO2, and RGO/NT were 3.25, 3.12, and 3.08 eV with absorption regions at the wavelengths of 382, 398, and 403 nm, respectively. The highest photocatalytic activity for RGO/NT for degrading naphthol blue was obtained at pH 5, with a photocatalyst mass of 60 mg, and an irradation of 15 min. Photocatalytic degradation by RGO/NT on Batik wastewater under visible light showed higher effectivity than under UV light.
... Thus, the CR photodegradation can be explained by the sight of this band structure. When the Cu 2 O@Gr composite is photoexcited, an (e − − h + pair is formed, and then the photoreaction between the dye and water species begins [46,[54][55][56]. According to the band structure of Figure 9b, the photoexcited electrons are allowed to transfer to the graphene conduction band, which may increase the photocatalysis performance of the doped graphene. ...
... Thus, the CR photodegradation can be explained by the sight of this band structure. When the Cu2O@Gr composite is photoexcited, an ( − ℎ ) pair is formed, and then the photoreaction between the dye and water species begins [46,[54][55][56]. According to the band structure of Figure 9b, the photoexcited electrons are allowed to transfer to the graphene conduction band, which may increase the photocatalysis performance of the doped graphene. ...
This work comprehensively studies both the photocatalytic degradation and the adsorption process of Congo red dye on the surface of a mixed-phase copper oxide–graphene heterostructure nanocomposite. Laser-induced pristine graphene and graphene doped with different CuO concentrations were used to study these effects. Raman spectra showed a shift in the D and G bands of the graphene due to incorporating copper phases into the laser-induced graphene. The XRD confirmed that the laser beam was able to reduce the CuO phase to Cu2O and Cu phases, which were embedded into the graphene. The results elucidate incorporating Cu2O molecules and atoms into the graphene lattice. The production of disordered graphene and the mixed phases of oxides and graphene were validated by the Raman spectra. It is noted from the spectra that the D site changed significantly after the addition of doping, which indicates the incorporation of Cu2O in the graphene. The impact of the graphene content was examined with 0.5, 1.0, and 2.0 mL of CuO. The findings of the photocatalysis and adsorption studies showed an improvement in the heterojunction of copper oxide and graphene, but a significant improvement was noticed with the addition of graphene with CuO. The outcomes demonstrated the compound’s potential for photocatalytic use in the degradation of Congo red.
... rGO has a similar, though thinner, sheet-like morphology that aggregates randomly with distinct edges, wrinkled surfaces, and folds (Shalaby et al., 2015). N-TiO 2 appeared spherical in shape (Asiri et al., 2011). Small spherical particles can be seen adhering irregularly and non-homogenously to the subjacent surface. ...
Methylene blue (MB) and hexavalent chromium Cr(VI) are hazardous pollutants in textile waste and cannot be completely removed using conventional methods. So far, there have been no specific studies examining the synthesis and activity of N-TiO2/rGO as a photocatalyst for removing MB and Cr(VI) from textile wastewater. This work especially highlights the synthesis of N-TiO2/rGO as a photocatalyst which exhibits a wider range of light absorption and is highly effective for simultaneous removal of MB-Cr(VI) under visible light. Titanium tetrachloride (TiCl4) was used as the precursor for N-TiO2 synthesis using the sol-gel method. Graphite was oxidized using Hummer's method and reduced with hydrazine to produce rGO. N-TiO2/rGO was synthesized using a hydrothermal process and then analyzed using several characterization instruments. The X-ray diffraction pattern (XRD) showed that the anatase N-TiO2/rGO phase was detected at the diffraction peak of 2θ = 25.60°. Scanning electron microscopy and transmission electron microscopy (SEM-EDS and TEM) dispersive X-ray spectrometry images show that N-TiO2 particles adhere to the surface of rGO with uniform size and N and Ti elements are present in the N-TiO2/rGO combined investigated. Gas absorption analysis data (GSA) shows that N-TiO2/rGO had a surface area of 77.449 m2/g, a pore volume of 0.335 cc/g, and a pore size of 8.655 nm. The thermogravimetric differential thermal analysis (TG-DTA) curve showed the anatase phase at 500-780 °C with a weight loss of 0.85%. The N-TiO2/rGO composite showed a good photocatalyst application. The photocatalytic activity of N-TiO2/rGO for textile wastewater treatment under visible light showed higher effectiveness than ultraviolet light, with 97.92% for MB and 97.48% for Cr(VI). Combining N-TiO2 with rGO is proven to increase the light coverage in the visible light region. Removal of MB and Cr(VI) can be carried out simultaneously and results in a removal efficiency of 95.96%.
... As shown in Figure 14B, the intensity of the absorption bands regarding various functional groups, including the -OH group (3400 cm −1 ) in cross-linked chitosan support, decreased after the adsorption of dye on the surface, and broadened bands with lower intensity were obtained. Besides that, the characteristic bands attributed to the benzene ring, -OH, carbonyl (-C=O), C-O and sulphonate (SO 3 − ) groups in phenol red dye molecule also disappeared, and this can be attributed to the homogeneous distribution of dye over the surface of cross-linked chitosan support [38,45]. ...
... regarding various functional groups, including the -OH group (3400 cm ) in cross-link chitosan support, decreased after the adsorption of dye on the surface, and broaden bands with lower intensity were obtained. Besides that, the characteristic bands attribu to the benzene ring, -OH, carbonyl (-C=O), C-O and sulphonate (SO3 − ) groups in phe red dye molecule also disappeared, and this can be attributed to the homogeneous dis bution of dye over the surface of cross-linked chitosan support [38,45]. To examine the reduction of the adsorbed dye, NaBH4 was duly added to the react mixture after the adsorption of dye over cross-linked chitosan support. ...
... Here, the adsorption a desorption of dye before and after the addition of the reducing agent, respectively, can chitosan support, decreased after the adsorption of dye on the surface, and bro bands with lower intensity were obtained. Besides that, the characteristic bands att to the benzene ring, -OH, carbonyl (-C=O), C-O and sulphonate (SO3 − ) groups in red dye molecule also disappeared, and this can be attributed to the homogeneou bution of dye over the surface of cross-linked chitosan support [38,45]. To examine the reduction of the adsorbed dye, NaBH4 was duly added to the r mixture after the adsorption of dye over cross-linked chitosan support. ...
In this study, glutaraldehyde cross-linked chitosan support, as well as the catalysts obtained after loading Ag metal (Ag/Chitosan), were synthesised and applied for adsorption and reduction of phenol red dye in an aqueous solution. The Ag/chitosan catalysts were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis techniques. The catalytic reduction and adsorption performance of phenol red dye with Ag/chitosan and cross-linked chitosan, respectively, was performed at ambient reaction conditions. The reduction of dye was carried out using sodium borohydride (NaBH4) as the reducing agent, while the progress of adsorption and reduction study was monitored with ultraviolet-visible (UV-vis) spectrophotometry technique. The reduction of the phenol red dye varied with the amount of catalyst, the concentration of NaBH4, Ag metal loading, reaction temperature, phenol red dye concentration and initial pH of the dye solution. The dye solution with a nearly-neutral pH (6.4) allowed efficient adsorption of the dye, while acidic (pH = 4) and alkaline (pH = 8, 11, 13.8) solutions showed incomplete or no adsorption of dye. The reusability of the Ag/chitosan catalyst was applied for the complete reduction of the dye, where no significant loss of catalytic activity was observed. Hence, the applicability of cross-linked chitosan and Ag/catalyst was thus proven for both adsorption and reduction of phenol red dye in an aqueous solution and can be applied for industrial wastewater treatment.
... In their study, it took 300 min to degrade 94% of PR. Asiri et al. fabricated TiO 2 nanocrystals with an average size of 77 nm that showed lower degradation time than 5 nm commercialized nanoparticles, which exhibited a higher photodegradation percentage of 95.2% during 100 min [24]. Other photocatalysts such as La-substituted bismuth ferrite (Bi 1-x La x FeO 3 ) and oxyhydroxide of Fe (III) (Goethite) have been used in the photodegradation of PR [25,26]. ...
... Hence, it can show how the presence of KBrO3 fostered the degradation of phenol red. Based on the advanced oxidation process, the phenomenon of phenol red degradation because of photocatalysis has been defined in some literature [24,37]. When the TiO2 compound is photoexcited, forming a pair of electron holes ℎ , the photolysis of the dye in water begins, as follows: ...
... Hence, it can show how the presence of KBrO 3 fostered the degradation of phenol red. Based on the advanced oxidation process, the phenomenon of phenol red degradation because of photocatalysis has been defined in some literature [24,37]. When the TiO 2 compound is photoexcited, forming a pair of electron holes (e − − h + ), the photolysis of the dye in water begins, as follows: ...
In this study, the enhanced photodegradation of a high-concentration phenol red (PR) using very fine TiO2 nanocrystals by adding a KBrO3 electron acceptor was reported for the first time. The structural study on TiO2 nanocrystals using HRTEM, XRD, Raman, and EDX was performed and it confirmed the anatase phase of TiO2 nanocrystals. UV–Vis absorbance of 20 mg.L−1 PR was measured and the photodegradation was extracted. The KBrO3 concentration effects exhibited an important enhancement in the degradation of PR dye. The efficiency of PR was increased during 110 min from 75% of pure TiO2 to 92% and 98% of TiO2 with 1 mg and 5 mg KBrO3, respectively. For different samples, a first-order kinetic of dye degradation is confirmed. The instantaneous amount of degraded dye increased from 150 to 180 and 197 mg/g TiO2 with 1 mg and 5 mg KBrO3, respectively. The mechanism of the photodegradation reaction confirms the effect of OH- radicals on increasing the photocatalytic activities. The addition of electron acceptors KBrO3 improved the photocatalysis rate, where it prevented e-h recombination through conduction band electron capture, which increases the concentration of hydroxyl radicals. The proposed mechanism and results were supported by photocurrent measurements and a Raman spectra analysis of the final photodegraded products. The photocurrent of TiO2 was observed at 1.2 µA, which was significantly improved up to 13.2, and 21.3 µA with the addition of 1 mg and 5 mg of KBrO3. The Raman spectra of the final products confirmed that SO42− and carbons are byproducts of PR degradation.
... For example, rhodamine 6G (R6G) is a highly stable laser dye that is very difficult to degrade under normal environment. Also, R6G dye is widely used in textile industry, causing serious pollution to the environment [29][30][31]. Therefore, in this study, a recognized tool of photocatalytic water remediation is performed to decompose the R6G dye pollutant under UV irradiation by using the CdS nanoparticles as photocatalyst. ...
Cubic-phase cadmium sulfide (CdS) nanoparticles were formulated through dropwise precipitation. XRD analysis shows that the CdS has an average nanocrystallite size of approximately 3.36 nm. FTIR results reveals that a strong band appeared around 600 cm-1 is due to Cd-S bonds. SEM image demonstrates that many tiny spherical nanoparticles are homogeneously distributed on the sample surface. The CdS nanoparticles show a prominent UV-Vis absorption peak at 506 nm with a direct band gap of 2.24 eV. CdS nanoparticles has induced remarkable photobleaching effect on the highly stable R6G dye solution under UV illumination, which is applicable for future wastewater treatment.
