Catalytic Degradation Of Methylene Blue Research Articles

Photocatalytic degradation of methylene blue dye from aqueous solution using TiO2 doped Activated carbon

The effluent coming out from the textile, paper and food industries containing dye is strongly coloured and reveals very harmful effects on living beings. In order to reduce wastewater pollution, the degradation of dye into non-toxic form is desirable. The photo catalytic degradation of methylene blue is reported in the present study. The irradiation of aqueous solution of methylene blue dye in presence of photo catalyst and UV light was carried out in the batch photo reactor. Titanium dioxide TiO2 /CFAC was used as photo catalyst for the study. The rate of decolorisation was estimated from residual concentration spectrophotometrically. Effects of various operating parameters such as the irradiation time, initial pH and the amounts of catalyst on the degradation of the dyes were investigated. Results show that the degradation kinetics fitted well to pseudo second order rate law. The maximum decolorizing efficiency occurred in less than 50min with 50mg of TiO2 /CFAC catalyst dose.

Multivalent iron-based magnetic porous biochar from peach gum polysaccharide as a heterogeneous Fenton catalyst for degradation of dye pollutants

Water contamination caused by organic dyes has become a significant concern, and catalytic degradation of dye pollutants is an effective solution. However, developing an affordable, easy-to-prepare, high-catalytic-activity, and renewable catalyst has proved challenging. The current study addresses this issue by introducing an efficient heterogeneous Fenton catalyst, known as multivalent iron-based magnetic porous biochar (mFe-MPB). This catalyst comprises multiple iron species, such as Fe3O4, γ-Fe2O3, zero-valent Fe (Fe0), and Fe3C. The mFe-MPB was easily prepared by utilizing a straightforward crosslinking-pyrolysis strategy with natural peach gum polysaccharide (PGP), which has a unique structure and composition that facilitates the creation of multivalent iron species. The mFe-MPB demonstrates high catalytic activity in the degradation of an array of dyes, including cationic dyes such as methylene blue (MB) and methyl violet (MV), as well as anionic new coccine (NC) dye. Its mass standardized rate constant value for catalytic degradation of MB can reach as high as 1.65 L min−1 g−1. Additionally, the catalyst can be easily recovered through magnetic separation and possesses remarkable structural stability, enabling several reuses without compromising its efficiency. Therefore, this study offers a viable strategy to fabricate low-cost, efficient and sustainable Fenton catalyst for removal of dye pollutants from water.

Cu/Fe co-modified nitrogen self-doped biochar as a heterogeneous Fenton-like catalyst for degradation of organic pollutants: Synthesis, performance, and mechanistic study

In this work, Cu/Fe modified nitrogen self-doped cyanobacterial biochar was synthesized for the first time as a heterogeneous Fenton-like catalyst to study its catalytic degradation ability of Methylene Blue (MB) organic dye. The prepared samples were characterized by SEM, BET, XRD, and so on. The effects of pyrolysis temperature, acid treatment, heat radiation source, H2O2 concentration, initial pH, and catalyst dosage on the degradation of MB were systematically investigated. The results showed that the catalytic degradation of MB by CuFeXBC400 catalyst was as high as 99.78% within 30 min under the optimum conditions. The catalytic degradation mechanism was derived based on quenching experiments and LC-MS. Cyanobacteria not only provided a carbon source as a biochar skeleton loaded with bimetals but also provided N source to promote Fe2+ and Fe3+ cycling in the Fenton reaction. In addition to its high catalytic activity, the catalyst can still reach 90% MB removal after five runs and calcination regeneration, which has good application prospects in the removal of organic pollutants from water.

Degradation performance of methylene blue in metal nanoparticle modified 3D mesoporous wood microchannels.

Wood has a rich three-dimensional pore structure and many bottom-up nanochannels. However, the structure of wood itself has limited ability to adsorb dyes, so the effective combination of the unique structure of wood and Pd NPs was studied to achieve efficient degradation of dyes. First, the three-dimensional structure of natural wood is optimized by combining the complex pore structure of wood with Pd NPs to improve the contact process between the dye and Pd NPs. Then, Pd (II) ion can be well reduced to Pd NPs by wood lignin. In addition, Pd NPs can be fixed by hydroxyl groups on cellulose in wood. The flow state inside Pd NPs/wood film and the contact area between catalyst and dye were discussed in detail by hydrodynamic simulation, which filled the gap. It provides reference for composite structure. When Pd NPs/wood membrane was used to treat methylene blue (MB), the degradation efficiency was up to 96.7%, which was 90% higher than that of natural wood. Its TOF value was 1.82 molMBmolPd-1min-1, which was higher than that in the previous literature. Therefore, the novelty of this study is that the mechanism of catalytic degradation of MB by Pd nanoparticles/wood composites is reported for the first time. The internal flow mode and contact condition of the new material are understood, which has a good application prospect.

E-Beam and γ-rays Induced Synthesis and Catalytic Properties of Copper Nanoclusters-Deposited Composite Track-Etched Membranes.

Effective removal of toxic inorganic and organic pollutants is one of the current leading challenges of wastewater treatment. In this study, the decomposition of methylene blue (MB) under UV light irradiation was investigated in the presence of copper nanoclusters (NCs)-deposited polyethylene terephthalate (PET) track-etched hybrid membranes. PET track-etched membranes (TeMs) with an average pore size of ~400 nm were grafted by functional acrylic acid (AA) monomer under electron beam irradiation after oxidation with H2O2/UV system. The radiation dose varied between 46 and 200 kGy. For the deposition of copper NCs, poly(acrylic acid) (PAA)-grafted membranes saturated with Cu(II) ions were irradiated either by electron beam or γ-rays to obtain copper-based NCs for the catalytic degradation of MB. Irradiation to 100 kGy with accelerated electrons resulted in the formation of small and uniform copper hydroxide (Cu(OH)2) nanoparticles homogeneously distributed over the entire volume of the template. On the other hand, irradiation under γ-rays yielded composites with copper NCs with a high degree of crystallinity. However, the size of the deposited NCs obtained by γ-irradiation was not uniform. Nanoparticles with the highest uniformity were obtained at 150 kGy dose. Detailed analysis by X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed the loading of copper nanoparticles with an average size of 100 nm on the inner walls of nanochannels and on the surface of PET TeMs. Under UV light irradiation, composite membranes loaded with NCs exhibited high photocatalytic activity. It was determined that the highest catalytic activity was observed in the presence of Cu(OH)2@PET-g-PAA membrane obtained at 250 kGy. More than 91.9% of the initial dye was degraded when this hybrid membrane was employed for 180 min, while only 83.9% of MB was degraded under UV light using Cu@PET-g-PAA membrane. Cu(OH)2@PET-g-PAA membranes obtained under electron beam irradiation demonstrated a higher photocatalytic activity compared to Cu@PET-g-PAA membranes attained by γ-rays.

Improving the Photo Electro Catalytic Degradation of Methylene Blue by Modified TiO2/ITO Photo Anodes

TiO2 photoanodes have gained significant attention for the removal of organic pollutants through photoelectrocatalytic processes, with the aim of developing a cost-effective and efficient method for improving the degradation of pollutants in surface water. This study investigated the effects of adding titanium nanooxide (Degussa P25) containing 70% anatase and 30% rutile phases on the properties of nanostructured TiO2 photoanodes prepared on glass substrates (indium tin oxide (ITO)) using sol–gel/dip coating techniques The results obtained from ultraviolet–visible transmittance spectroscopy, electrochemical (EC) impedance spectroscopy, photocurrent, and atomic force microscopy analyses revealed that the addition of Degussa P25 improved the electrical conductivity of the TiO2/ITO anode and reduced the optical bandgap from 3.50 to 3.35 eV, while the size of the titanium oxide particles decreased to about 75 nm. The EC impedance spectra measurement confirms that the addition of titanium nanooxide Degussa P25 improved the electrical conductivity for TiO2/ITO anode. The photoelectrocatalysis (PEC) performance of the TiO2 photoanodes was investigated via the degradation of methylene blue (MB) under UVA light irradiation. The AB photoanode (with the addition of Degussa P25) exhibited excellent PEC performance, with 95.9% color removal efficiency and 63% total organic carbon (TOC) removal efficiency, compared to 92% color removal efficiency and 56% TOC removal efficiency for the A photoanode (without the addition of Degussa P25). The kinetic constants (k) were 134 × 10−4, 110 × 10−4 (min−1) for A and AB anodes, respectively, and the degradation of MB followed first-order kinetics for all anodes. The A and AB anodes were compared as electrodes for the degradation of MB using PEC, photocatalysis (PC), and EC technologies. Subsequently, The A and AB anodes were utilized as electrodes to compare the performance of PEC, PC, and EC technologies for the degradation of MB. The results showed that the AB anode exhibited higher efficiency in all PC technologies, with color removal (%) efficiencies of 95.9% (PEC), 33% (PC), and 21% (EC) compared to 92% (PEC), 28% (PC), and 19% (EC) for the A anode. Additionally, the photooxidation process had a 2.1% effect on the degradation of the initial MB concentration.

Preparation of Bismuth Tungstate/Preoxidized Acrylonitrile/Acrylic Acid Copolymer Composite Nanofiber Membrane and Its Photocatalytic Properties.

In this patent article, a novel bismuth tungstate/preoxidized acrylonitrile/ acrylic acid (AN/AA) copolymer composite nanofiber membrane was prepared, which was used as the visible light catalyst. AN/AA copolymer was synthesized, which was electrospun with bismuth nitrate and sodium tungstate to prepare the composite nanofiber. Then the composite nanofiber was preoxidized to prepare the bismuth tungstate/preoxidized AN/AA composite nanofiber membrane containing adsorption moiety and photocatalytic active moiety. The photocatalytic activity of bismuth tungstate/preoxidized AN/AA composite nanofiber membrane with different preoxidized temperature, heating rate, and holding time by catalytic degradation of methylene blue was investigated. The optimal preoxidized conditions were as follows: the preoxidized temperature was heated to 200 °C with the heating rate of 1°C/min and the holding time at this temperature was 12 h. The chemical structure and morphology of the composite nanofiber membrane were characterized by FTIR, XRD, and SEM. The bismuth tungstate/preoxidized AN/AA composite nanofiber membrane obtained good photocatalytic properties and reusability under visible light. The degradation rate of methylene blue by this visible light catalyst could reach 90.24% for 4.5 h, and the degradation rate remained 81.53% for 4.5 h after 5 reuses.

Acetic acid mediated fabrication of highly exposed Fe(III)/Fe(II) sites in Fe2O3/MA for enhanced peroxymonosulfate activation

The design and synthesis of efficient heterogeneous catalysts with the accessible and mixed-valence metal centers for the activation of peroxymonosulfate (PMS) is an important research topic in water pollution control. In this work, the highly efficient catalysts Fe2O3/MA have been successfully synthesized with acetate acid as an important regulating agent. Methylene blue (MB) has been applied as the organic pollution for catalysis experiments and Fe2O3/MA-1.5 can achieve 98% catalytic degradation of MB at a concentration of 10 mg/L in 100 min, showing much higher catalytic efficiency than those of single MA (acetate modified MIL-53(Fe)) (60%) and Fe2O3 (57%). Electron paramagnetic resonance (EPR) spectroscopy and radical scavenging experiments have shown that hydroxyl radical (•OH), sulfate radical (•SO4ˉ), and singlet oxygen (1O2) all participate and contribute to the degradation process. The efficient catalytic mechanisms have been carefully studied. X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and pyridine Fourier transformed infrared (py-FT-IR) have successfully proved the construction of highly exposed coordinatively unsaturated sites and the coexistence of Fe(III)/Fe(II) double catalytic centers in Fe2O3/MA-1.5, which function together with the high dispersion of Fe2O3 on MA to realize the final high activation activity for PMS. Further research shows that the initial coordination of acetic acid with Fe sites and the departure of acetic acid after vacuum treatment help construct highly exposed Fe(III)/Fe(II) double catalytic sites in Fe2O3/MA-1.5. Eventually, the intermediates produced in the reaction were analyzed by gas chromatography mass spectrometry (GC-MS), and the degradation pathway has been tentatively proposed. This study has proposed a new route to build active sites in catalysis, which shows high application potential for the effective degradation of organic pollutants in water.

Green synthesis of silver nanoparticles using Stachys spectabilis: Identification, catalytic degradation, and antioxidant activity

Nanotechnology has become the focus of scientific research due to its widespread and effective use. Silver nanoparticles (AgNPs) were produced utilizing Stachys spectabilis, and their antioxidant effect and catalytic degradation of methylene blue were investigated. The structure of ss-AgNPs was clarified by spectroscopy. FTIR demonstrated the possible functional group responsible for reducing agents. The absorption at 498 nm in the UV–Vis measurement verified the nanoparticle structure. XRD measurement demonstrated the nanoparticles to be face-centered cubic crystalline structures. TEM image proved the nanoparticles as spherical, and the size was determined as 10.8 nm. The intense signals at 2.8–3.5 keV in EDX confirmed desired product. The observation of zeta potential at −12.8 mV indicated the stability of nanoparticles. The nanoparticles can degrade the methylene blue with 54% at 40 h. The antioxidant effect of extract and nanoparticles was performed by ABTS radical cation, DPPH free radical scavenging, and FRAP assay. Nanoparticles revealed excellent ABTS activity (4.42 ± 0.10) in comparison to the standard BHT (7.12 ± 0.10). ss-AgNPs may be a promising agent for the pharmacy.

Ultrasound-enhanced catalytic degradation of simulated dye wastewater using waste printed circuit boards: catalytic performance and artificial neuron network-based simulation.

Recent developments of heterogeneous advanced oxidation for refractory organic contaminants and catalysts made of solid waste have attracted much attention. In this work, waste printed circuit board (wPCB) was used for catalytic degradation of simulated textile wastewater enhanced by ultrasound. Catalytic degradation of rhodamine B (RhB) and methylene blue (MB) was conducted in the presence of H2O2. Effect of ultrasound, wPCB, H2O2, pH, and dye concentration was investigated by single factor experiments. The growing catalytic efficiency was determined by ultrasound. The removal efficiency of MB and RhB are influenced by wPCB, H2O2, pH, and dye concentration. Degradation efficiency is accelerated with increasing wPCB dosage and H2O2 and decreasing dye concentration. Effective degradation of MB and RhB is obtained under broader pH region, attractively at neutral pH. Under optimal conditions, MB removal reaches 98.83% at 90min while RhB removal reaches 99.57% at 80min. Hydroxyl radicals play an important role in catalytic process. Tentative mechanism for catalytic degradation of MB and RhB are discussed based on multiple characterizations. Superior reusability of wPCB proves that wPCB is highly durable catalyst. Due to low cost and high efficiency, wPCB is attractive as effective catalyst for treatment of organic wastewater. Artificial neuron network-based (ANN) simulation, as a widely used artificial intelligence algorithm, was one of preferred methods for the wastewater treatment due to its unique properties in solving complex processes. An ANN model was designed for the prediction of the performance of ultrasound-enhanced catalytic degradation with a high R value (0.99).

Catalytic degradation of methylene blue by biosynthesized Au nanoparticles on titanium dioxide (Au@TiO2).

The degradation of methylene blue is a critical procedure in its wastewater remediation and thus has inspired wide catalysis research with semiconductors such as titanium dioxide (TiO2) and rare metals such as gold (Au). In this study, we report bacterial cells assisting biosynthesis for Au@TiO2 as an efficient catalyst for the catalytic degradation of methylene blue. Multiple complementary characterization for bio-Aux@TiO2 evidenced the evenly distributed Au nanoparticles (NPs) on the bio-TiO2 layers. Meanwhile, bio-Au2@TiO2 displayed the superior catalytic activity in the degradation of methylene blue with the highest kinetics constant (kapp) value of 0.195 min-1. In addition, bio-Au2@TiO2 keeps stable catalytic activity for up to 10 cycles. The origin of the catalytic activity was investigated by the hydroxyl radical fluorescence quantitative analysis and optical band gap analysis. In the bio-Au2@TiO2 catalytic system, Au NPs decreased the band gap energy of TiO2 and enabled the generation of abundant photogeneration hydroxyl radicals, resulting in an enhanced photocatalytic activity. Our microbial synthesized bio-TiO2 and bio-Aux@TiO2 study would be useful for developing green synthesis catalyst technology.

Novel in-situ synthesis of copper oxide nanoparticle in smart polymer microgel for catalytic reduction of methylene blue

The present study involves the synthesis of poly-(N-isopropylmethacrylamide-co-methacrylic acid) [p(NiPmA-mAc)] microgels for the stabilization of copper oxide nanoparticles (CuO NPs) via free radical precipitation approach and synthesized material as a catalyst for catalytic degradation of methylene blue (MB) dye. Results clearly indicate that p(NiPmA-mAc) microgel not only serves as an excellent micro-reactor but also works as an effective stabilizing / fabricating medium for the successful synthesis of CuO NPs. UV–Vis spectra of CuO-[p(NiPmA-mAc)] showed the maximum peak was observed at 400 nm. Scanning electron microscopic (SEM) and X-ray diffraction (XRD) analysis showed spherical morphology of in-situ synthesized CuO NPs with crystalline size of 20 ± 4 nm. Different parameters which affect catalytic reduction reactions such as pollutant/catalyst dose, reductant concentration and effect of time were investigated. Results showed that the apparent rate constant for catalytic reduction of MB was 0.5307 min−1. The application of the CuO NPs loaded p(NiPmA-mAc) microgel catalyst for catalytic degradation of MB has shown excellent results with complete degradation (100%) within 15 min. Further, the recyclability of the CuO-[p(NiPmA-mAc)] catalyst has shown promising results during four consecutive cycles thus, confirming its stability.

Photocatalytic Degradation of Textile Dye on Blended Cellulose Acetate Membranes.

This work aimed to investigate the degradation performance of natural cellulose acetate (CA) membranes filled with ZnO nanostructures. Photocatalytic degradation of reactive toxic dye methylene blue (MB) was studied as a model reaction using UV light. A CA membrane was previously casted and fabricated through the phase inversion processes and laboratory-synthesized ZnO microparticles as filler. The prepared membrane was characterized for pore size, ultrafiltration (UF) performance, porosity, morphology using scanning electron micrographs (SEM), water contact angle and catalytic degradation of MB. The prepared membrane shows a significant amount of photocatalytic oxidation under UV. The photocatalytic results under UV-light radiation in CA filled with ZnO nanoparticles (CA/ZnO) demonstrated faster and more efficient MB degradation, resulting in more than 30% of initial concentration. The results also revealed how the CA/ZnO combination effectively improves the membrane’s photocatalytic activity toward methylene blue (MB), showing that the degradation process of dye solutions to UV light is chemically and physically stable and cost-effective. This photocatalytic activity toward MB of the cellulose acetate membranes has the potential to make these membranes serious competitors for removing textile dye and other pollutants from aqueous solutions. Hence, polymer–ZnO composite membranes were considered a valuable and attractive topic in membrane technology.

Photocatalytic Properties of Zinc Selenide and Cobalt Selenide Nanocomposite

In recent years, the environmental pollution caused by organic dyes has become more and more serious, so the removal of organic dyes has been paid more and more attention. In this work, ZnSe/CoSe was synthesized by hydrothermal method, and the activity of the composite photocatalytic materials was detected by visible light catalytic degradation of methylene blue. The nanocomposites were characterized by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Energy Dispersive Spectrometer (EDS), X-ray Powder Diffraction (XRD), Ultraviolet Diffuse Reflection Spectrum (UV-Vis), Brunner−Emmet−Teller Measurements (BET), and X-ray Photoelectron Spectroscopy (XPS). The catalytic effect was the most obvious when the composite ratio was 1:7.5, with the removal rate reaching to 99.4 % of 20 mg/L MB within 120 min of visible light irradiation. Therefore, ZnSe/CoSe has a broader application prospect due to its high efficiency and low price.

Catalytic degradation of methylene blue using iron and nitrogen-containing carbon dots as Fenton-like catalysts

Carbon dots were modified with iron and nitrogen groups to produce specific surface groups and charge which demonstrated high efficiency for the Fenton-like degradation of methylene blue whilst markedly minimising its effluent toxicity.

Sustainable Synthesis of Silver Nanoparticles Using Marine Algae for Catalytic Degradation of Methylene Blue

Herein, Sargassum coreanum (marine algae)-mediated silver nanoparticles (AgNPs) were successfully synthesized by a simple reduction method. The synthesized AgNPs were characterized using ultraviolet-visible spectroscopy, attenuated total reflection Fourier transformed infrared spectroscopy, X-ray diffractometry, field emission scanning electron microscopy (FESEM) with energy-dispersive X-ray (EDX) spectroscopy, and high-resolution transmission electron microscopy (HR-TEM) analysis. The acquired colloidal AgNPs were strongly absorbed around 420 nm and displayed brown color under visible light. The XRD pattern of AgNPs exposed their face-centered cubic geometry along with crystalline nature. The HRTEM images of synthesized AgNPs confirmed the mean particle size of 19 nm with a distorted spherical shape, and the calculated interlayer distance (d-spacing value) was about 0.24 nm. Further, the catalytic degradation of methylene blue using sodium borohydride and AgNPs was monitored using UV–vis spectroscopy. The result revealed that AgNPs performed as a superior catalyst, which completely degraded MB in 20 min. The rate constant for MB degradation was calculated to be 0.106 min−1, demonstrating that the marine algae-mediated AgNPs had outstanding catalytic activity. This approach is easy and environmentally benign, which can be applied for environmental-based applications such as dye degradation and pollutant detoxification.

A new Cu(II) metal–organic architecture driven by ether-bridged dicarboxylate: Photocatalytic properties and Hirshfeld surface analysis

A new Cu(II) coordination polymer with formula {[Cu(L)(bbi)(H2O)]•H2O}n (1) (H2L = 1,3-bis(3ˊ-carboxylatophenoxy)benzene, bbi = 1,1′-(1,4-butanediyl)bis(imidazole)), has been prepared and characterized using microanalysis, single crystal and powder X-ray diffraction techniques. The polymer 1 possess 1D double chain, which further extends into 2D layer through packing and hydrogen bond interactions. The polymer has been used as an effective photocatalyst for the photodisintegration of aromatic dyes viz. methyl violet (MV), Rhodamine B (Rh B) and methylene blue (MB). The results suggest that 1 is best photocatalyst for MB and decomposed 84.14% MB in 100 min following pseudo-first order reaction with rate constant k 0.01873 min−1. Furthermore, the possible photocatalytic mechanism exhibited by 1 for the catalytic degradation of MB was proposed using the trapping experiments and LC-MS methodology which suggested that ·OH is the main reactive oxygen species involved in photodecomposition of MB. In addition, band gap calculations and Hirshfeld surface analysis have been done to substantiate the photocatalytic mechanism.

Sustainable synthesis of silver nanoparticles using Alstonia scholaris for enhanced catalytic degradation of methylene blue

The present work described a simple, green, and fast approach for the synthesis of silver nanoparticles using an aqueous fruit extract of Alstonia scholaris(AS-AgNPs). The role of plant extract was identified as both reducing as well as capping agent in the synthesis of AS-AgNPs. The formation of AS-AgNPs was confirmed through the visible color change from pale yellow to brown and the respective surface plasmon resonance (SPR) peak observed at 426 nm in the UV-Visible (UV-Vis) spectrum. Further, the synthesized AS-AgNPs were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy with Energy dispersive spectrum (SEM with EDS), High resolution transmission electron microscopy (HR-TEM), and Dynamic light scattering (DLS) with Zeta potential. The DLS derived average particle size and poly dispersion index (PDI) of AS-AgNPs are about 50 nm and 0.664 with Zeta potential of -22.4 mV, suggested the presence of mono and polydispersive AS-AgNPs with good stability. The synthesized AS-AgNPs were mainly distributed (56 %) as a quasi-spherical shape with size ranges from 5 to 50 nm revealed by SEM and TEM images. Moreover, the catalytic reduction of methylene blue (MB) by AS-AgNPs has been accessed via time-dependent UV-Vis spectroscopy. The UV-Vis results suggested that AS-AgNPs show enhanced catalytic activity on the reduction of MB by aqueous sodium borohydride with pseudo first-order kinetics and the calculated rate constant was about 0.7 × 10−3 s−1. Overall, the green synthesized AS-AgNPs have a great catalytic potential in the degradation of MB in water.

Fabrication of biomass-derived polymer with dopamine and Ag nanoaggregates: Prevention of the biofilm of bacteria and catalytic degradation of organic dyes

Efficacious and convenient removal of pollutants from wastewater is a worldwide challenge and a significant threat to public health and all ecosystem. Here in the present work, we synthesized a novel type of biomass-derived hollow polymer functionalized with dopamine (DA) and silver, named as (BHP@PDA/Ag) hollow catalyst. The biomass-derived hollow polymer (BHPs) was first prepared by the precipitation polymerization of trans-anethole (ANE) and maleic anhydride (MAH). After obtaining the BHP, the microspheres were modified with dopamine to obtain BHP@PDA and further incorporated with the silver nanoaggregates on its surface. The prepared BHP@PDA/Ag materials were used as a catalyst for dyes and antibacterial activates. The antibacterial activities were conducted against E. coli with different concentrations of BHP@PDA/Ag and also with laser treatment which showed a tremendous antibacterial ability. Moreover, the biofilm activity was also performed against Pseudomonas aeruginosa (PA) and E. coli. The BHP@PDA/Ag inhibited the biofilm of both bacteria strongly after exposure to bacterial culture solution at 37 °C for 24 h. In addition, BHP@PDA/Ag was used as a catalyst with the reducing agent NaBH4 and without the reducing agent for the degradation of methylene blue (MB) dye and acid red (AR) in wastewater, where an 89% degradation rate for MB and 93% for AR in 100 mg·L-1 solution with the reducing agent was achieved. While without the reducing agent, the degradation rate of 81% for MB and 78% for AR were achieved, respectively. The BHP@PDA/Ag catalyst exhibited high stability and recyclability. Kinetic studies revealed that the catalytic degradation of MB and AR proceeded according to a pseudo-first-order kinetics model. Overall, the remarkable performance of BHP@PDA/Ag catalyst makes them multifunctional materials for practical applications.

Co3O4/CoO ceramic catalyst: Bisulfite assisted catalytic degradation of methylene blue

Here in, a system of Co3O4/CoO catalyst activated with the aid of bisulfite (NaHSO3) was established for the decomposition of methylene blue (MB). The Co3O4/CoO material was designed by a two-step uniform precipitation and calcination method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) spectroscopy to detect the crystallinity, morphology, magnetic ability, element valence and the different types of free radicals, respectively. The efficient degradation of MB relies on the synergistic effect between the Co3O4/CoO catalyst and bisulfite (NaHSO3) to generate some strongly oxidizing radicals, which could achieve a MB degradation rate of 90.7% within 40 min using this novel system. Additionally, the ferromagnetic property of Co3O4/CoO catalyst is expected to supply an excellent magnetic separation ability to help separate the solid catalyst from the aqueous solution. The novel catalyst system of Co3O4/CoO/NaHSO3 may serve as a promising new system for wastewater treatment.