Degradation Of Organic Dye Pollutants Research Articles

Recyclable Mussel-Inspired Magnetic Nanocellulose@Polydopamine-Ag Nanocatalyst for Efficient Degradation of Refractory Organic Pollutants and Bacterial Disinfection.

Development of a novel strategy to tackle bacterial-contaminated complex industrial wastewaters containing refractory organic pollutants is of great demand. In this study, polydopamine (PDA)-coated magnetic cellulose nanofiber (MCNF)-loaded silver nanoparticle (AgNP) (MCNF/PDA-Ag) nanocomposites were designed and applied for efficient degradation of organic dye pollutants and inactivation of Escherichia coli (E. coli) in wastewater. In the presence of NaBH4, MCNF/PDA-Ag could achieve a high catalytic reduction rate of 6.54 min-1 for the removal of methylene blue. Similarly, it showed good catalytic reduction performance for methyl orange (0.63 min-1) and 4-nitrophenol (2.94 min-1). The MCNF/PDA-Ag nanocomposites can be easily magnetically recycled and reused with negligible loss of catalytic performance. Moreover, this nanocatalyst also exhibited excellent disinfection performance against E. coli, with more than 99% disinfection ratio at very low doses (50 μg/mL). Overall, this work provides new insights into a delicate design of advanced magnetically recyclable silver nanocomposites with ultrahigh catalytic rates and excellent antibacterial properties from sustainable nature biomass.

Construction of a ternary staggered heterojunction of ZnO/g-C3N4/AgCl with reduced charge recombination for enhanced photocatalysis.

In this study, a series of ternary composite photocatalysts ZnO/g-C3N4/AgCl(x) (x is the amount of AgCl added, x=0.05, 0.1, 0.15 g) were synthesized, and various characterization methods were used to analyze the morphology, structural, and photochemical properties of the above samples. The photocatalytic activity of the obtained samples was evaluated by degrading rhodamine B (RhB) and acid orange (AOII) under xenon lamp irradiation. The results show that the degradation rate of ZnO/g-C3N4/AgCl (0.1 g) is 99% within 60 min, which is much higher than the 38% degradation rate of g-C3N4. After five cycles, the degradation efficiency of RhB and AOII by ZnO/g-C3N4/AgCl (0.1 g) were still 85% and 94%, respectively. In addition to colored dyes, the photocatalytic degradation of colorless tetracycline hydrochloride (TCH) compounds was also investigated to understand the effect of photosensitization on the degradation process. Based on the electronic structure analysis of the DFT calculations, a staggered heterojunction structure was found between g-C3N4, ZnO, and AgCl. The enhanced photocatalytic activity of the ternary composite is mainly attributed to the efficient separation of charge carriers through the synergistic removal of photogenerated electrons in g-C3N4 by ZnO and AgCl. Radical trapping experiments confirmed that •O2- and h+ were the main active species in the reaction system. As a visible light-responsive catalyst, ZnO/g-C3N4/AgCl can be effectively applied to the degradation of organic dye pollutants and has broad application prospects.

Mechanistic Insights into Graphene Oxide Driven Photocatalysis as Co-Catalyst and Sole Catalyst in Degradation of Organic Dye Pollutants

Photocatalysis is a promising route to utilize sunlight, which has been potentially used to solve energy as well as environmental problems with an emphasis on fundamental understanding and technological applications in society. Semiconductors are excellent photocatalysts but often show less efficient activities due to the fast recombination of photogenerated charge carriers and very slow kinetics of surface photochemical reactions. However, recent advancements show promising strategies to improve their photocatalytic activities, including surface modifications using suitable co-catalysts and the development of novel efficient photocatalysts. Graphene oxide (GO) is one of such nanomaterials which shows multifarious roles in photocatalysis with a great potential to act as an independent solar-driven sole photocatalyst. In this minireview, the photochemistry of GO has been discussed in view of its multifarious roles/mechanisms in improving the photocatalytic activity of metal oxide semiconductors, plasmonic nanomaterials, and also their nanocomposites. In addition, recent advancements and applications of such GO-based photocatalysts in photocatalytic degradation of organic dye pollutants, including engineering of GO as the sole photocatalyst, have been discussed. Furthermore, the challenges and future prospects for the development of GO-based photocatalysts are discussed.

Magnetic porous carbon composites for rapid and highly efficient degradation of organic pollutants in water

A magnetic porous carbon composite (MPC) was prepared from metal−organic frameworks (MOFs) by the one-step calcination method. The MPC was characterized by SEM, TEM, TG, DTG, Raman and XPS. The adsorption and degradation performance of MPC towards four organic dyes were investigated. The maximum adsorption amount of magenta on MPC was 191.94 mg g -1 at 25 °C. Furthermore, the MPC showed remarkable stability for it can be recycled 5 times through the facile magnetic separation without obvious loss of activity. The degradation efficiency of MPC toward four kinds of organic pollutants was nearly 100% within 36 ​min, which was much higher than that previously reported. • Magnetic Porous Carbon Composites is prepared by one step carbonization with excellent adsorption and catalytic degradation performance. • Maximum adsorption capacity of magenta on MPCs is 191.94 ​mg ​g −1 and nearly 100% degradation efficiency within 36 ​min. • Ultra-fine nanocrystalline Fe 3 O 4 nanoparticles embedded in the octahedral structure, are favor of removal and degradation of organic dye pollutants. • Carbon layer in MPCs is beneficial to avoid secondary pollution in degradation and contribute the stability and recyclability of MPCs. • MPCs possesses potential green and effective application of organic pollutants treatment in complex matrix.

Boosted electron-transfer/separation of SnO2/CdSe/Bi2S3 heterostructure for excellent photocatalytic degradation of organic dye pollutants under visible light

Nowadays, the discharge of hazardous pollutants from industries into drinking water has become a significant issue worldwide. In the present work, SnO2/CdSe/Bi2S3 heterostructure photocatalyst along with pristine SnO2, CdSe, and Bi2S3 was synthesized via a facile hydrothermal route. The fabricated catalysts were characterized by different analytical techniques such as X-ray diffraction (XRD), Atomic force microscopy (AFM), Dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), UV-visible diffuse reflectance spectroscopy, and Electrochemical impedance spectroscopy (EIS) to study the structural, morphological, optical, and electrochemical properties, respectively. The XRD diffractograms confirmed the formation of nanocomposite having SnO2 (Tetragonal), CdSe (Cubic), and Bi2S3 (Orthorhombic) phases. The photocatalytic experiment results showed that the nanocomposite catalyst exhibited excellent photodegradation than individual catalysts. The nanocomposite catalyst degraded methylene blue (MB) dye entirely after 60 min in visible light illumination, considerably higher as compared to pristine SnO2 (53.8%), CdSe (78.5%), and Bi2S3 (86.3%). The nanocomposite catalyst also has the potential to degrade various pollutants such as rhodamine B (RhB), methyl orange (MO), safranin-O (SO), and methyl red (MR) dyes with efficiency 99.8, 91.7, 75.0, and 98.5 %, respectively, with superior reusability up to 5th cycles against MB dye. The narrow optical energy bandgap in the visible region (UV results), the more significant flow of charge carrier at the catalyst's surface (EIS results), and higher electron-transfer/separation achieved by the heterostructure formation responsible for the boosted photocatalytic activity of nanocomposite catalyst. Furthermore, the present finding introduced an efficient photocatalyst with improved charge carrier kinetics for water purification applications.

Facile fabrication of g-C3N4/CdS heterojunctions with enhanced visible-light photocatalytic degradation performances

The construction of heterojunction used to improve the photocatalytic performance of photocatalyst has attracted much attention in recent years. In this study, we aim to investigate the synergistic effect of g-C 3 N 4 and CdS on photocatalytic degradation of organic dye pollutants. Several g-C 3 N 4 /CdS heterojunctions with different g-C 3 N 4 contents were successfully synthesised via a simple hydrothermal reaction. Experimental measurements on photocatalytic degradation of methylene blue (MB), rhodamine B (RhB) and MB/RhB mixtures were conducted. The photodegradation results indicate that the prepared g-C 3 N 4 /CdS composites all demonstrate remarkable visible-light photocatalytic properties, and this performance is due to the formation of the g-C 3 N 4 /CdS heterojunction structures. Compared with pure g-C 3 N 4 and CdS, the g-C 3 N 4 /CdS heterojunctions not only effectively enhance the absorption of visible light but also significantly inhibit the recombination of photogenerated carriers. Thus, this condition prolongs the lifetime of active species and markedly improves their photodegradation activities. Especially, the 0.04GCS exhibits the best photocatalytic degradation performance on MB, and its degradation rate constant is up to 0.0301 min −1 within the irradiation time of 90 min, which is 9 and 3 times higher than that of the pure g-C 3 N 4 and CdS, respectively. In the meantime, the 0.12GCS also shows excellent photodegradation activity on RhB, and its degradation efficiency is nearly 2.32 and 2.97 times that of the pure g-C 3 N 4 and CdS. The different degradation behaviours of the composite photocatalysts on MB/RhB mixed pollutant were investigated. The possible reaction mechanism of the photocatalytic degradation on organic dyes by the g-C 3 N 4 /CdS heterojunctions was also explored.

Green synthesis of gold nanoparticles (Au NPs) using Rosa canina fruit extractand evaluation of its catalytic activity in the degradation of organic dye pollutants of water

The current investigation involves the novel biogenic synthesis of Au nanoparticles (Au NPs) templated over the Rosa canina fruit extract. Different phytochemicals like polyphenols, ascorbic acid, flavonoids, tannins etc contained in the plant extract facilitate the green reduction of Au ions and further stabilizations of Au NPs by encapsulation. The as synthesized sustainable material was characterized by several advanced analytical techniques. Towards its application, it was found to be an efficient catalyst in the reductive degradation of toxic water pollutant organic dyes like Methylene blue (MB), Rhodamin B (RhB) and 4-nitrophenol (4-NP) over NaBH4 at room temperature. Time dependent UV–Vis spectroscopy was used to follow up the reactions which revealed that the reactions were completed within very short time (60 sec). The nanomaterial was easily isolable from the reaction mixture and recycled several times with almost consistent reactivity.

Facile Green Fabrication of Zno Nanoparticles by Using an Aqueous Leaf Extract of Citrus Medica L. For Photocatalytic Degradation of Organic Dye Pollutant, Antibacterial and Antioxidant Activities

Facile Green Fabrication of Zno Nanoparticles by Using an Aqueous Leaf Extract of Citrus Medica L. For Photocatalytic Degradation of Organic Dye Pollutant, Antibacterial and Antioxidant Activities

Heterogeneous activation of peroxymonosulfate by stable Co-MOF for the efficient degradation of organic dye pollutants

A new Co-MOF with splendid stability can act as an excellent heterogeneous catalyst to activate peroxymonosulfate, exhibiting highly efficient organic dye degradation in aquatic environments.

Improved visible light-driven photocatalytic degradation of methylene blue and methyl red by boron-doped carbon quantum dots.

The synthesis of fluorescent carbon quantum dots (CQDs) and their applications have attracted great attention due to their excellent properties. Especially, the unique visible-light absorption and photo-induced electron transfer properties make CQDs available in photocatalytic degradation of organic dye pollutants in water resources. Herein, we synthesized nondoped CQDs and boron-doped CQDs (B-CQDs) by hydrothermal method and compared their photocatalytic degradation activity of methylene blue (MB) and methyl red (MR) dyes under visible light irradiation. The characterization outcomes showed that the optical and structural properties can be easily improved by doping with hetero-atom, thereby photocatalytic performance. As expected, the photodegradation performance of both organic dyes in model solutions by B-CQDs was higher than that of CQDs. MB and MR dyes were photodegraded over 95% by B-CQDs in 90 and 120 min visible light irradiation, respectively. Eventually, the results revealed that nondoped CQDs and B-CQDs are excellent candidates for the degradation of organic dyes because of their high photocatalytic performance under visible light illumination.

In situ deposition of silver nanoparticles on polydopamine‐coated manganese ferrite nanoparticles: Synthesis, characterization, and application to the degradation of organic dye pollutants as an efficient magnetically recyclable nanocatalyst

The present paper reports a facile in situ synthesis strategy for the production of MnFe2O4@PDA‐Ag magnetically recyclable core–shell nanospheres by the deposition of silver nanoparticles (AgNPs) to the surface of MnFe2O4@PDA nanocomposites through the reduction of silver ions by the outer polydopamine (PDA) layer. The deposition of AgNPs over MnFe2O4@PDA was validated by scanning electron microscopy–energy‐dispersive X‐ray spectroscopy (SEM‐EDX), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and vibrating sample magnetometer (VSM) analysis. The catalytic reduction performance of the obtained MnFe2O4@PDA‐Ag nanospheres were tested over model organic dye pollutants (i.e., methylene blue [MB] and 4‐nitrophenol [4‐NP]) by sodium borohydride. Notably, the as‐prepared MnFe2O4@PDA‐Ag nanocatalyst exhibited significantly enhanced catalytic activity for the reduction of MB (296.52 s−1 g−1) and 4‐NP (92.02 s−1 g−1) compared with the other types of similar Ag‐ and PDA‐based catalytic systems in the recent literature. Moreover, the MnFe2O4@PDA‐Ag nanocatalyst showed excellent recyclability, ease of magnetic separation, and rapid and higher recovery ability with insignificant loss in their catalytic efficiencies even after several cyclic uses. The PDA coating on the surface of MnFe2O4 NPs allocates the surface functionalization for the building of novel catalyst systems. This work presents a simple and practicable for the synthesis of MnFe2O4@PDA‐Ag nanospheres that could have a great potential for the treatment of organic pollutants in wastewater and variety of applications in catalysis.

Synthesis and characterization of [formula omitted] composite as photocatalyst for the degradation of organic dyes

Increasing anthropogenic and industrial activities lead to the contamination of aquatic resources with organic pollutants such as dyes. In this work, a magnetic composite photocatalyst composed of Fe3O4, BiOCl, and Cu2O was fabricated for the degradation of organic dye pollutants. The composite was synthesized via a simple co-precipitation method. FT-IR and SEM-EDX analyses confirmed the formation of Fe3O4/BiOCI/Cu2O (FBC) composite. Photocatalytic degradation was tested under UV, and visible light using model organic dyes, methyl orange (MO), and methylene blue (MB), and was monitored using UV–Vis spectroscopy. The absorbance was found to decrease corresponding to the reduction of dye concentration during photocatalytic degradation. A plot of absorbance versus irradiation time for both model dyes exhibited exponential decay; faster degradation was observed with MO than with MB. Furthermore, the degradation of both dyes using the FBC photocatalyst was more efficient under UV light.

Fabrication of CNTs-Ag-TiO2 ternary structure for enhancing visible light photocatalytic degradation of organic dye pollutant

In order to improve the catalytic efficiency of titanium dioxide (TiO2) under visible light, TiO2 nanoparticles was composed with the silver-covered carbon nanotubes (CA) to form CNTs-Ag-TiO2 (CAT) ternary structure via in situ reduction combined with sol-gel method. The composite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectra (DRS) and photoluminescence (PL) spectra. Using methylene blue (MB) as the model pollutant, photocatalytic activity of CAT was studied to investigate the influence of the composited amount of CA on the effect of photocatalysis. The results revealed that the photocatalytic activity of TiO2 under both visible light and UV light were improved by compositing with CA. When the mass ratio of CA is 15%, the degradation rare of methylene blue (MB) by CAT reached to 80.8% under visible light in 3 h, which is 16.5 times higher than that of TiO2. Accordingly, the degradation rate reached to 99.2% under UV light in 40 min, which is nearly twice as fast as that of TiO2.

Probe sonication synthesis of ZnFe2O4 NPs for the photocatalytic degradation of dyes and effect of treated wastewater on growth of plants

Today world is facing water pollution resulting from various sectors and presenting serious ecological concerns. The reusability of polluted water could be a promising study for the sustainable wastewater management strategy. In this, prepared ZnFe2O4nano-photocatalyst was employed for photocatalytic degradation of organic dye pollutants namely Acid Red 88 (AR-88), Acid Orange 8 (AO 8) and Malachite Green (MG) under Sun light and UV irradiation. The UV-induced dye degraded wastewater samples were used to examine the green assessment towards the growth of Eleusine coracana (Finger millet) and Vigna unguiculata (Black eyed beans) plant. The results showed excellent plant growth in dye degraded wastewater sample noticed in the period of 3–5 days compared to pure water as control and with retard growth observed in dye solution. Thus, present research reported that the sustainability issues related to photodegradation of contaminated dye solution using prepared nano material was tested and efficiently using treated waste water in growing plants.

Highly dispersed Mn2O3−Co3O4 nanostructures on carbon matrix as heterogeneous Fenton‐like catalyst

This work reports the synthesis of various carbon (Vulcan XC‐72 R) supported metal oxide nanostructures, such as Mn2O3, Co3O4 and Mn2O3−Co3O4 as heterogeneous Fenton‐like catalysts for the degradation of organic dye pollutants, namely Rhodamine B (RB) and Congo Red (CR) in wastewater. The activity results showed that the bimetallic Mn2O3−Co3O4/C catalyst exhibits much higher activity than the monometallic Mn2O3/C and Co3O4/C catalysts for the degradation of both RB and CR pollutants, due to the synergistic properties induced by the Mn−Co and/or Mn (Co)−support interactions. The degradation efficiency of RB and CR was considerably increased with an increase of reaction temperature from 25 to 45°C. Importantly, the bimetallic Mn2O3−Co3O4/C catalyst could maintain its catalytic activity up to five successive cycles, revealing its catalytic durability for wastewater purification. The structure–activity correlations demonstrated a probable mechanism for the degradation of organic dye pollutants in wastewater, involving •OH radical as well as Mn2+/Mn3+ or Co2+/Co3+ redox couple of the Mn2O3−Co3O4/C catalyst.

Synthesis and characterization of a novel manganese ferrite–metal organic framework MIL-101(Cr) nanocomposite as an efficient and magnetically recyclable sonocatalyst

A magnetic MnFe2O4/MIL-101(Cr) nanocomposite was synthesized and applied as a novel sonocatalyst for enhanced degradation of organic dye pollutants.

MIL-101(Cr)-cobalt ferrite magnetic nanocomposite: synthesis, characterization and applications for the sonocatalytic degradation of organic dye pollutants.

In this study, for the first time, a novel magnetically recyclable MIL-101(Cr)/CoFe2O4 nanocomposite was prepared via a facile solvothermal method. The morphology, structural, magnetic and optical properties of the nanocomposite were characterized via field emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), UV-visible spectroscopy (UV-visible) and BET surface area analysis. Furthermore, the sonocatalytic activity of the MIL-101(Cr)-based magnetic nanocomposite was explored for the degradation of organic dye pollutants such as Rhodamine B (RhB) and methyl orange (MO) under ultrasound irradiation in the presence of H2O2. Under optimized conditions, the degradation efficiency reached 96% for RhB and 88% for MO. The sonocatalytic activity of MIL-101(Cr)/CoFe2O4 was almost 12 and 4 times higher than that of the raw MIL-101(Cr) and pure CoFe2O4, respectively. The improved sonocatalytic performance of the as-prepared binary nanocomposite can be attributed to the relatively high specific surface area of MIL-101(Cr) and magnetic property of CoFe2O4, as well as the fast generation and separation of charge carriers (electrons and holes) in MIL-101(Cr) and CoFe2O4. In addition, the trapping tests demonstrated that ·OH radicals are the main active species in the dye degradation process. Moreover, the most influencing factors on the sonocatalytic activity such as the H2O2 amount, initial dye concentration and catalyst dosage were investigated. Finally, the nanocomposite was magnetically separated and reused without any observable change in its structure and performance even after four consecutive runs.

Effect of Microwave Irradiation on Physical Adsorption Accuracy and Photocatalytic Activity of Nano-ZnO Materials

Trace toxic organic compounds, such as dyes and polymer additives, can cause serious environmental pollution and threaten human health. Therefore, photocatalytic degradation of organic dye pollutants as an abiotic means has attracted much attention. In the process of preparing ZnO by precipitation method, a series of nano-ZnO materials were obtained by microwave radiation with different power. The crystal structure, morphology and surface physicochemical properties of the synthesized materials were characterized. The results show that the surface area has different degrees of increase compared with the ZnO prepared by the ordinary precipitation method. After different power microwave irradiation, the photocatalytic activity of ZnO has been improved to different extents, and is significantly higher than the commercially available P25 and ZnO without microwave irradiation.

Ag loaded B-doped-g C3N4 nanosheet with efficient properties for photocatalysis

Three material engineering strategies in the form of doping (Boron-doping), nanostructuring (nanosheet (NS) formation) and decorating with plasmonic nanoparticles (loading with Ag metal), were integrated to improve the photocatalytic activity of graphitic carbon nitride (gC3N4). Concentrations of B-doping and Ag-loading were optimized to maximize the catalytic performance in the final nanocomposite of Ag-loaded B-doped gC3N4 NS. Combined effect of all three strategies successfully produced over 5 times higher rate towards degradation of organic dye pollutant, when compared to unmodified bulk gC3N4. Detailed characterization results revealed that incorporation of B in gC3N4 matrix reduces the band gap to increase the visible light absorption, while specific surface area is significantly enhanced upon formation of NS. Decoration of Ag nanoparticles (NPs) on B-doped gC3N4 NS assists in fast transfer of photogenerated electrons from gC3N4 to Ag NPs owing to the interfacial electric field across the junctions and thus reduces the recombination process. Investigations on individual strategies revealed that decoration of Ag NPs to induce better charge separation, is the most effective route for enhancing the photocatalytic activity.

A Laboratory-based Experiment on the Efficacy of Graphitic Carbon Nitride Doped with Tungsten Chloride in the Purification of Industrial Wastewater through Degradation of Organic Dye Pollutant

Water is an essential commodity whose quantity and quality needs to be secured for easier accessibility at both the industrial, public and household levels. However, its availability in adequate quality and quantity has continued to decline worldwide. Indeed, rise in human population coupled with the climate change phenomena have greatly impacted on the quality of water resources through increased organic and inorganic pollution. Rhodamine B (RhB) dye is a common organic pollutant majorly in industrial wastewater and with numerous environmental and human health effects. The application of graphitic carbon nitride (G-C3N4) in the purification of industrial wastewater to enhance the removal of RhB is a technology of interest to most environmental quality regulators and agencies. The study was therefore aimed at investigating the performance of graphitic carbon nitride doped with tungsten chloride in the degradation of organic dye pollutant rhodamine B dye from industrial wastewater. The study showed that the as-prepared hybrid photo catalyst exhibits an improved photo degradation performance because of its synergetic effect. Indeed, the photo excited electrons from g-C3N4 were able to efficiently separate and are injected to the conductive band of WO3. The optimum photo activity occurred at the optimum ratio of 0.25WO3/g- C3N4. There was also stability and efficiency within the hybrid catalyst within the photo degradation process. Indeed, the composite indicates a high activity for degradation of RhB under visible light irradiation. The presence of g-C3N4 proved to be beneficial for enhancement in photo catalytic activity of the g-C3N4-WO3 composite and proved to be one of the best alternative modes of n the degrading organic dye pollutant Rhodamine B dye from wastewater.