Method For Photocatalytic Degradation Research Articles

Comparison of ZnO Nanoparticles Prepared by Spray Pyrolysis and Consecutive Method for UV-Driven Photocatalytic Degradation of Methylene Blue

ZnO is a semiconductor material that is widely used for many applications in industries such as solar cells, dye-sensitized solar cells, food packaging, photocatalytic, anti-microbial, light-emitting diode devices, and gas sensors. In this study, ZnO nanoparticles (NPs) have been successfully synthesized using two methods, namely spray pyrolysis and a consecutive method. The consecutive method is a combination of sol-gel and spray drying methods. The objective of this study is to investigate the photocatalytic performance of ZnO fabricated using those methods. Both methods used the same precursor, zinc acetate dehydrate as a source of zinc, but with different solvents and additives. Based on the X-ray diffraction pattern, the ZnO NPs synthesized using spray pyrolysis and a consecutive method exhibited similar polycrystalline hexagonal wurtzite structures. The large crystal sizes of ZnO NPs were obtained using a consecutive method, sol-gel followed by spray drying, in comparison with those from the ZnO spray pyrolysis. In contrast, the particle size of ZnO prepared by the consecutive method was in a smaller range. The SEM analysis implied that the ZnO structures had surface defects. In the UV-driven photocatalytic degradation of methylene blue, ZnO produced by the consecutive method exhibited slightly higher degradation performance than ZnO spray pyrolysis. This performance was attributed to the larger crystal size of ZnO NPs, which provided a longer carrier movement at semiconductor surfaces and reduced electron-hole recombination. Additionally, ZnO NPs produced using the consecutive method underwent agglomeration that leads to a smaller contact surface with methylene blue, obstructing the degradation process.

Novel 3D plate-like g-C3N4/BiOCl heterojunction as a highly efficient photocatalyst for the degradation of carbofuran in wastewater under visible light irradiation

The g-C3N4/BiOCl (gCN-BCl) heterojunction photocatalyst was synthesized using a low-temperature precipitation method for effective photocatalytic degradation of carbofuran (CBF). All gCN-BCl composites demonstrate greater efficacy in removing CBF compared to its individual constituents. The synergistic effect of incorporating the 0D structured BiOCl onto the 2D structured g-C3N4 was comprehensively examined using various microscopic, X-ray, and spectroscopic analytical techniques. Additionally, optical and photoelectrochemical analyses were conducted. The findings validated that the interaction between the two semiconductors at the heterointerfaces enhanced remarkable physical and structural stability, promoted high charge separation and transfer properties, and improved photocatalytic degradation. Under optimal conditions, 5-gCN-BCl (0.25 g/L) achieved a CBF (5 mg/L) removal efficiency of 95.7 % under visible light irradiation of 120 min, achieving 3.1- and 5.9-times higher degradation rate than the pure BiOCl and g-C3N4, respectively. The radical trapping experiments indicated that the h+ and •O2− were the primary reactive species involved in the CBF degradation. Furthermore, the potential toxicity of CBF and its intermediates was assessed, revealing that the photocatalytic degradation process significantly lowered the ecotoxicity of pesticide wastewater. The potency of 5-gCN-BCl was also evaluated in tap water and real wastewater samples, with CBF degradation efficiencies of 85.8 %, 47.6 %, and 38.7 % in tap water, municipal, and pesticide industry wastewater, respectively. Additionally, artificial neural network (ANN) modeling was employed to predict and optimize the photocatalytic degradation process, providing further insights into the system’s performance. The outcomes of this work offer valuable insights into the development of heterojunction photocatalysts with superior stability and efficacy for eliminating pesticides from water bodies.

“Sunlight-driven catalytic degradation of MB dye and multi-cycle Re-usability analysis of Cu2-xSe nanoparticles”

One of the best ways to remove organic dyes based contaminant from water resources and industrial waste water is the sunlight driven photo-catalytic degradation method. The theme of the present investigation is the photocatalytic degradation of methylene blue (MB) dye using economically produced Cu2-XSe nanoparticles (NPs) catalyst under solar radiations. The Cu2-XSe NPs crystallized in the cubic structural phase with an average crystallite size around 19 nm. The direct band gap was found to be 2.1 eV. The PL spectra and corresponding CIE diagram show the Cu2-xSe NPs emitted yellow color. The SEM micrographs show that the small grains staked over others to form large grains or patches. The FTIR and EDX spectra confirmed the formation of Cu2-XSe NPs. The obtained optimum photocatalytic degradation efficiency for Cu2-XSe NPs is 90.3 %. For first cycle analysis. The pseudo-first order and second order models were used to analyze the kinetic data of Cu2-XSe NPs for varying concentrations. The multiple-cycle degradation analysis by catalyst of MB dye in one day spam for continuous four cycles were also analysed and discussed. The sun light driven multi-cycle catalytic degradation confirms the re-usability of Cu2-xSe NPs for the treatment of industrial waste water and other contaminated water bodies for the survival of aquatic life and for saving environment.

Ce-doped ZnO nanonails synthesized by a simple thermal evaporation method for photocatalytic degradation

One-dimensional (1D) nanomaterials have garnered significant scientific and technological attention due to their potential applications in electronics devices, gas sensing, energy conversion, and photocatalysis. However, the development of a simple and low-cost technique for 1D nanostructure synthesis remains a challenge. The doping of ZnO nanostructures has proven to be an effective way to improve their internal properties. In this work, one-dimensional ZnO and Ce-doped ZnO nanorods and nanonails were synthesized by a simple thermal evaporation method using different weight ratios of ZnS and CeO2 precursor powders in a catalyst-free process. The effects of cerium doping concentration on the structural, morphological, and optical properties of the as-prepared samples were investigated. XRD analysis confirmed that the crystal structure was converted from the cubic ZnS phase to the hexagonal ZnO phase with increasing annealing temperatures. The UV–Vis spectra showed that the optical absorption edge of Ce-doped ZnO samples was slightly red-shifted. Additionally, the band gap energy decreases with increasing cerium concentration. SEM images showed that the morphology of the structures obtained changed from nanorods to nanonails as the Ce content increased. The incorporation of Ce ions into the ZnO matrix has been successfully confirmed by HRTEM, Raman, and EDX analysis. Photocatalytic activity studies showed that Ce-doped ZnO samples exhibited significantly enhanced photocatalytic performance compared to pure ZnO for the degradation of rhodamine B under UV radiation. These results may suggest the use of heterogeneous photocatalysis as an efficient, cheap, and environment-friendly alternative for the removal of pollutants from water and the use of Ce-doped ZnO as a promising candidate.

Synthesis and mechanism of Bi/SnO2 for enhanced photocatalytic activity in the degradation of humic acid under visible light

Humic acid (HA) is a typical refractory organic matter, widely existing in natural water and many types of wastewaters. In this study, Bi/SnO2 composites were synthesized by a simple one-step hydrothermal method for photocatalytic degradation of HA. Due to the surface plasmon resonance (SPR) effect of Bi, the light absorption of Bi/SnO2 composites expands from UV to visible light compared to pure SnO2. Under visible light irradiation for 120 min, the UV254 removal reached 93.58 %, color number (CN) removal reached 94.41 %. The degradation rate constant of Bi/SnO2 (0.0178 min−1) is 14.83 times higher than that of SnO2 (0.0012 min−1), indicating the superior photocatalytic degradation efficiency of Bi/SnO2 composites. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was found that photocatalysis mainly degraded most CHO-containing organic matter and reduced the amount of organic matter (from 7240 to 3886). The molecular number of organic compounds with m/z of 400–500 and 500–600 exhibited a significant decrease, specifically by 1052 and 770, respectively. This observation suggests that the photocatalytic process effectively eliminates low and moderate molecular weight organics. The molecular number, aromaticity and molecular weight of dissolved organic matter (DOM) were reduced mainly by carboxylic acid reaction, dealkylation reaction and oxygen addition reaction.

Microwave-assisted hydrothermal synthesis of Ag/Bi2MoO6/ZnO heterojunction with nano Ag as electronic accelerator pump for high-efficienty photocatalytic degradation of levofloxacin

The fluoroquinolone antibiotics, as a category of emerging refractory organic pollutants, have triggered intensive attention due to their persistent ecotoxicology for aquatic environments. Herein, a novel Ag/Bi2MoO6/ZnO (Ag/BMO/ZnO) heterojunction was prepared using a two-step microwave-assisted hydrothermal method for photocatalytic degradation of levofloxacin (LFX). The optimal Ag/BMO/ZnO delivers higher photocatalytic degradation efficiency toward LFX reaching 86.4 %, which is 3 times and 7 times higher than those of neat Bi2MoO6 and ZnO, respectively. This can mainly be attributed that the existence of heterojunction between Bi2MoO6 and ZnO promotes the transmission of photogenerated charges (e−/h+). Furthermore, the introduction of Ag nanoparticles serves as an electron accelerator pump, which can also effectively accelerate the transport and separation of the photogenerated e−/h+. Both of these indirectly retard the recombination of e−/h+. The radical capture assays demonstrate that 1O2, OH, h+ and O2– are responsible for the the degradation of LFX and the 1O2 is the primary reactive oxygen species (ROS). Moreover, based on the identification of degradation intermediates via the liquid-chromatography-mass spectrometry (LC-MS) technique, the possible degradation routes of LFX were plausibly inferred. In conclusion, this work provides a new perspective toward antibiotics removal by developing novel heterojunction photocatalysts anchored with precious nanoparticles.

Photocatalytic degradation of Alizarin Red contaminant using Ag2CrO4@NiFe-LDH composite under visible light irradiation.

In this study, Ag2CrO4@NiFe-LDH nanoparticles were synthesized by hydrothermal method for photocatalytic degradation of Alizarin Red (AR) dye. Three composites with different molar percentages were prepared, among which 50%Ag2CrO4@50%NiFe-LDH composite was the best sample with a removal rate of 97.1% in AR degradation. Also, the properties, structure, and characteristics of pure Ag2CrO4 and NiFe-LDH and their composites were determined by XRD, FESEM, FTIR, EDX mapping, and UV-visible analyses. It was found that Ag2CrO4@NiFe-LDH composites with the formation of heterogeneous structure of Z-scheme, in addition to increasing the active sites and increasing the specific surface, decrease the recombination rate of pure Ag2CrO4 and NiFe-LDH. Also, the Box-Behnken design technique, which is one of the most common designs used in response surface methodology, was used to optimize the operating conditions and investigate the effect of 4 independent parameters: catalyst amount, solution concentration, pH, and light intensity. The importance of independent parameters and their interactions were determined by ANOVA. By means of numerical optimization, the optimal values of the selected parameters equal to 1.34 g/L of catalyst, concentration of 16.45 mg/L, pH = 10.74, and light intensity of 15.53 W were obtained as optimal conditions with a desirability coefficient of 1.00 and an absorption value of 89.34%. The closeness of adjusted R2 (0.9838) and predicted R2 (0.9507) values show that this model can be successfully used for prediction.

Construction of scheelite CaWO4 with natural diatomite for boosted photocatalytic degradation of tetracycline and doxycycline antibiotics under natural conditions

Fabrication of efficient and recyclable catalysts with natural supporting materials is still a challenge in the field of photocatalysis. In the present work, scheelite type calcium tungstate was successfully constructed with natural diatomite via in-situ co-precipitation method for effective photocatalytic degradation of tetracycline (TC) and doxycycline (DC) antibiotics. The as-synthesized photocatalysts were characterized by SEM-EDX, TEM, BET, XRD, XRF, XPS, FTIR, UV–vis DRS, PL and EIS techniques. The morphological and physiochemical analyses confirmed the successful hybridization of CaWO4 with natural diatomite. The optical, photoluminescence and electrochemical tests confirmed that the composite material displayed narrower band gap energy, lower recombination rate and facilitated separation of photogenerated carriers. After construction of CaWO4 with the diatomite structure, the TC and DC decomposition efficiencies were found 4.70 and 2.54 times higher than that of the pristine sample, respectively. Furthermore, the composite catalyst showed superior degradation performances (91.8 % for TC and 90.7 % for DC) in the presence of hydrogen peroxide as a Fenton-agent. The enhanced photocatalytic performance was assigned to the increased specific surface area and pore volume, decreased band gap energy, limited recombination rate of photoinduced carriers, decreased charge transfer resistance as well as the abundant of hydroxyl radicals. The degradation reaction was found to be mainly driven by photogenerated holes and superoxide radicals. The CWO@DT/Vis/Fenton catalytic system exhibited good performance at near-neutral pH, also the composite catalyst was sufficiently utilized in the presence of co-existing anions. Furthermore, the photocatalytic efficiency was also tested under natural sunlight irradiation and the TC degradation remained 71.4 % after four cycles, indicating the outstanding feature of the composite catalyst in outdoor process conditions. Under these circumstances, the present work demonstrated the utilization potential of natural diatomite for effective photocatalytic remediation of antibiotic molecules under natural sunlight irradiation.

A novel hydrogen-bonded organic framework/g-C3N4 heterojunction for improved sulfadiazine photodegradation via effective electron transfer

As one of the most widely used antibiotics, sulfamethoxazole (SDZ) poses significant health risks to the ecological environment by causing harm to aquatic organisms and accelerating evolution of antibiotic resistant bacteria. Metalloporphyrin hydrogen-bonded organic framework (PFC-72) demonstrates promising prospect in the field of photocatalysis owing to its high specific surface area, wide light harvesting range, stable physical and chemical properties, and semiconductor properties. Herein, we constructed an efficient photocatalyst PFC-72/g-C3N4 by one-step solvent thermal method for photocatalytic degradation of SDZ. When doping content of PFC-72 is 10 %, photocatalytic degradation efficiency of SDZ can reach 96.82 % after 120 min of visible light irradiation, and PFC-72/g-C3N4 exhibits excellent structural stability. The photocatalytic efficiency of SDZ is improved by increasing specific surface area, enhancing absorption range of visible light, and inhibiting recombination of photogenerated electron-hole pairs. In addition, photodegradation pathways of SDZ in PFC-72/g-C3N4 was determined by UPLC-MS/MS analysis. Finally, dominant reactive species (·O2−, hVB+, and ·OH) in the system were detected through free radical masking experiments, and photocatalytic mechanism was clarified. This work investigates a novel and efficient porphyrin-HOF based photocatalyst, which has great potential for degradation of SDZ.

Characterization of low-molecular-weight fucoidan prepared by photocatalysis degradation and its regulation effect on metabolomics of LPS-stimulated macrophages

Fucoidan (ANP) from Ascophyllum nodosum demonstrates significant anti-inflammatory activity. Because lower-molecular-weight polysaccharides usually process even better bioactivities, in the present study, the photocatalytic degradation method with TiO2 and H2O2 was used to prepare low-molecular-weight derivatives (D-ANP-1.5 and D-ANP-3.5) with molecular weight of 5.0 kDa and 2.3 kDa, respectively. The characteristics of D-ANP-1.5 and D-ANP-3.5 were identified by chemical composition analysis, high-performance gel permeation chromatography, high-performance liquid chromatography photo-diode array mass, and Fourier transform-infrared spectrum, and compared with that of original fucoidan. The sulfate group retention rates of D-ANP-1.5 and D-ANP-3.5 were over 90.0% and the fucose and total sugar contents increased. However, the uronic acid and protein contents were decreased and the functional groups were not changed during degradation. Subsequently, 7 oligosaccharides in D-ANP-3.5 were identified by high-performance liquid chromatography-electrospray ionization detector mass and 6 of them were sulfated. Moreover, D-ANP-3.5 (2.3 kDa) supplement showed stronger inhibition effect of nitric oxide production than D-ANP-1.5 and undegraded ANP in LPS-stimulated RAW 264.7 cells. In addition, metabolic profiles results indicated that arginine biosynthesis, phenylalanine, tyrosine, and tryptophan biosynthesis, the TCA cycle, purine metabolism, and glutathione metabolism, along with influencing metabolic biomarkers such as betaine, arginine, NAD+, ATP, and pyroglutamic acid, were involved in the effects of D-ANP-3.5. The superior regulation effect on metabolomics in LPS-stimulated RAW 264.7 cells of D-ANP-3.5 could be attributed to its relatively low molecular weight and high fucose content. The present study advance understanding of the mechanism for the anti-inflammation of D-ANP-3.5.

Cu–ZrO2@GO scaffold: Visible spectrum triggered caffeine degradation and microbial inactivation

Consumption of beverages with caffeine has increased in last decade and has led to increase in the concentration of caffeine in various water bodies, placing it in the category of emerging contaminants (ECs). Sewage treatment plants are incapable of completely removing ECs and therefore use of photocatalysis as tertiary treatment is the need of the hour. Reported is a visible light active Copper doped Zirconium oxide loaded Graphene oxide based (Cu–ZrO2@GO) composite using co-precipitation method for photocatalytic degradation of caffeine. The composite was characterized using physiochemical techniques such as FTIR, XPS, XRD, FE-SEM, HR-TEM, UV-DRS, PL, and BET for its successful synthesis confirming distribution of Cu–ZrO2 (5–40 nm) over GO matrix. With the band gap energy of 2.5 eV, Cu–ZrO2@GO could effectively degrade 81.18% for caffeine in 240 min (min) under optimum conditions (pH 3, dose 70 mg) due to its high surface area (80.57 m2 g−1) with pore diameter of 37.4 Ao mainly by the hydroxyl radical as reactive oxygen species (ROS). Proposed degradation mechanism for caffeine is supported by LC/MS analysis. Cu–ZrO2@GO could degrade 78% of caffeine in tea extract (real sample) as confirmed by HPLC studies. Reported composite also depicted antibacterial activity against Gram-positive staphylococcus aureus (S. Aureus) and Gram-negative Escherichia Coli (E. coli) bacteria and could be recycled upto four cycles. Cu–ZrO2@GO can effectively be used for wastewater remediation.

Enhanced photocatalytic performance of Ga2O3 hollow spheres prepared by hard template technique

Semiconductor-assisted photocatalytic treatment has been regarded as a promising technique to dispose the dye-contaminated wastewater and gained pronounced attention recently. Here, we demonstrated a kind of Ga2O3 nanometer hollow sphere photocatalysis by template-assisted technique and applied it on the degradation of Rhodamine B (RhB). It was found that the hollow spherical structure of photocatalyst can greatly enhance the photo absorption and reduce the recombination of photogenerated carriers, thus improve the photocatalytic performance. This study provides a new method for efficient photocatalytic degradation of RhB, and provides a new idea for subsequent degradation work.

BiOBr/Cu2S p-n heterojunction for efficient photodegradation of ciprofloxacin and tetracycline under visible light

With the increasing needs of people for a better life, the problem of water resources pollution has attracted wide attention. The construction of p-n heterojunction is an effective strategy to promote the removal of pollutants by photocatalysts. In this work, a series of BiOBr/Cu2S heterojunction photocatalysts with mass ratios of Cu2S have been synthesized successfully by a hydrothermal method combined with grinding method for photocatalytic degradation of tetracycline (TC) and ciprofloxacin (CIP). The results showed that BiOBr/Cu2S exhibited superior photodegradation efficiency of TC and ciprofloxacin CIP than BiOBr and Cu2S monomers. When the mass ratio of Cu2S is 0.15 %, the visible degradation of CIP and TC are 79.2 % in 90 min and 88.5% in 60 min. In addition, the effects of different inorganic ions and pH value on the photocatalytic performance of BiOBr/Cu2S were investigated. It was proved that superoxide free radical (•O2-) was the main active species by free radical trapping experiment. The photocatalytic degradation process was further evaluated by total organic carbon and mass spectrometry tests. This work provides a feasible construction strategy for photocatalysts with potential application in water resources pollutants.

Synthesis of Cerium-Doped Zinc Oxide Nanocomposites and Their Application for Photocatalytic Degradation of Lambda-Cyhalothrin in Agricultural Runoff Under Natural Solar Irradiation

Heterogenous photocatalysis is one of the promising methods of degradation of organic pollutants in the environment. This study developed a suitable and efficient method for photocatalytic degradation of Lambda-cyhalothrin LCY pesticide using Ce–ZnO nanocomposites under natural solar irradiation. Ce–ZnO was synthesized using the coprecipitation method and was ascertained through structural characterization. The crystal structure and crystallite size, surface morphology, functional groups present, and the elemental composition of the synthesized nanocomposites were determined by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray spectroscopy (EDAX), respectively. The average crystallite size of the nanocomposites was found to be 31.42 nm. The photocatalytic degradation of LCY was conducted in batches to obtain and determine the optimal conditions for the degradation of the pesticide. It was found that at optimum conditions; 100 ppm LCY initial concentration, 20 mg dose of the photocatalyst, and 10–11 UV index, Ce–ZnO were found to degrade about 92% of the initial concentration of LCY after 3 h of exposure to solar irradiation. It was found that Ce–ZnO possesses high photocatalytic activity against LCY and the kinetic of the degradation was found to fit the pseudo-first-order kinetic model.

Electronic and photocatalytic properties of N, V co-doped anatase TiO2

Photocatalytic technology has good stability and ecological friendliness which is used to treat organic pollutants in wastewater. In this paper, TiO2, 1.5%V–TiO2 and N, V co-doped TiO2 were synthesized by hydrothermal method for photocatalytic degradation of tetracycline. Meanwhile, XRD, HRTEM, SEM, FT-IR, XPS, UV–Vis DRS, PL and electrochemistry tests were used to characterize the catalysts. The results showed that the appropriate amount of N, V co-doped can cause structural changes of TiO2. The co-doped of N and V enhanced the photocurrent response of TiO2, increased the specific surface area, reduced the band gap, and improved the efficiency of photodegradation of tetracycline. Accordingly, the tetracycline photocatalytic degradation path was proposed. 6%N-1.5%V–TiO2 completely degraded tetracycline into CO2, H2O and NO3−. The calculation results show that an appropriate amount of N, V co-doped TiO2 decreased bandgap, improved the optical absorption performance of TiO2. This work demonstrated the potential of N, V co-doped to design efficient photocatalysts.

Photocatalytic Degradation of Malachite Green by Titanium Dioxide/Covalent Organic Framework Composite: Characterization, Performance and Mechanism.

In this paper, a titanium dioxide/covalent organic framework (TiO2/COF) composite was prepared and its photocatalytic removal of dye was investigated. Using tetrabutyl titanate as a titanium source, TiO2 nanomaterial was prepared by sol-gel method. In the presence of TiO2, TiO2/COF core-shell composite was prepared by solvothermal synthesis using melamine and 1,4-phthalaldehyde as ligands. The prepared materials are characterized by SEM, TEM, XPS, XRD, TG, FTIR, BET, EPR, PL, and UV-Vis-DRS techniques. Using malachite green as a model of dye wastewater, the photocatalytic degradation performance of TiO2/COF composites was investigated under the irradiation of ultraviolet light. The results show that the modification of COF significantly improves the photocatalytic efficiency of TiO2, the degradation rate increases from 69.77 % to 93.64 %, and the reaction rate constant of the first-order kinetic equation is increased from 0.0078 min-1 to 0.0192 min-1. Based on the free radical capture experiment, the photocatalytic degradation mechanism of TiO2/COF was discussed, and the feasibility of its photocatalytic degradation of malachite green was theoretically clarified. Accordingly, a simple and practical method for photocatalytic degradation of malachite green was constructed, which has potential application value in the degradation of dye wastewater.

Novel ultrasonic technology for advanced oxidation processes of water treatment.

Textile wastewater accounts for a significant proportion of industrial wastewater worldwide. In particular, dye wastewater accounts for a large proportion and consists of non-degradable dyes, which are substances resistant to biodegradation. Methylene blue is a representative example of such non-degradable dyes. It is not biologically degraded and exhibits toxicity. Various methods for their decomposition are currently being studied. Advanced oxidation processes (AOPs), which generate highly reactive hydroxyl radicals that oxidize and degrade pollutants, have been actively studied. Particularly, the photocatalytic degradation method using TiO2 nanoparticles is one of the most actively studied fields; however, there are still concerns regarding the toxicity of nanoparticles. Research is currently being conducted on AOPs using the cavitation phenomenon of ultrasonic waves. However, achieving high efficiency using existing ultrasonic equipment is difficult. Therefore, in this study, we evaluated a new water treatment technology through AOPs using a focused ultrasonic system with a cylindrical piezoelectric ceramic structure. After determining the optimal conditions for degradation, the degradation process was evaluated as a useful tool for mitigating the toxicity of methylene blue. We found that, under the optimal conditions of 100 W intensity at a frequency of 400 kHz, this system is a helpful instrument for degradation and a new water treatment technology suitable for removing ecotoxicity and genotoxicity.

Visible-light-active type-II heterojunction CdS@Cu0.5Mg2.5SnS4 composites for the efficient removal of brilliant green dye

The effect of different percentages of CdS on the structural, optical, and morphological properties of Cu0.5Mg2.5SnS4 (CMTS) synthesized using a microwave method for photocatalytic degradation of brilliant green dye.

Enhanced photocatalytic degradation of methylene blue dye using fascily synthesized g-C3N4/CoFe2O4 composite under sun light irradiation

In this work, we have reported a successful synthesis of g-C3N4/CoFe2O4 nanocomposite material using a facile co-precipitation method for photocatalytic degradation of methylene blue dye (MB). The crystalline structure, functional groups present, Surface area, Band gap energy and surface charge of the synthesized photocatalysts were investigated by powder x-ray diffraction (PXRD), Fourier transfer Infrared (FTIR) Spectroscopy, BET, UV–Vis spectroscopy and pHpzc techniques respectively. The pXRD result reveals the formation of desired phases of g-C3N4, CoFe2O4, and g-C3N4/CoFe2O4 composite. The energy band gap pure g-C3N4, CoFe2O4, and g-C3N4/CoFe2O4 materials are found to be 2.53, 2.71, and 2.35 eV respectively. The g-C3N4/CoFe2O4 composite achieved the highest surface area of 262.49 m2/g than that of single components. The photocatalytic efficiency of the synthesized materials was investigated by the degradation of MB. Among the synthesized materials, g-C3N4/CoFe2O4 showed highest photocatalytic efficiency of 97.4 % than g-C3N4 and CoFe2O4 which is possibly due to the band gap enhancement and effectively reduces the recombination rate of electron-hole pairs during the photocatalytic reaction. The photocatalytic activities of the g-C3N4/CoFe2O4 composite were also investigated at varying pH of solution, contact time, initial concentration of MB, and photocatalyst dose in order to get the optimized conditions. The reactive species were identified in the catalytic system using ammonium oxalate, ascorbic acid and methanol as hole, superoxide radical and hydroxide radical scavengers respectively. The inhibition appeared from the hole scavenger is the highest and followed by superoxide and hydroxide radicals. From the scavenger experiment, it could be understood that all the reactive species contributed to MB degradation.

Carbon dots as potential candidate for photocatalytic treatment of dye wastewater.

Water is the utmost important element for the existence of life. In recent decades, water resources have become highly contaminated by a variety of pollutants, especially toxic dyes that are harmful to both living beings and environment. Hence, there is an urgent need to develop more effective methods than traditional wastewater treatment approaches for treatment of hazardous dyes. Herein, we have addressed the various aspects related to the effective and economically feasible method for photocatalytic degradation of these dyes employing carbon dots. The photocatalysts based on carbon dots including those mediated from biomass have many superiorities over conventional methods such as utilization of economically affordable, non-toxic, rapid reactions, and simple post-processing steps. The current study will also facilitate better insight into the understanding of photocatalytic treatment of dye-polluted wastewater for future wastewater treatment studies. Additionally, the possible mechanistic pathways of photocatalytic dye decontamination, several challenges, and future perspectives have also been summarized.