Catalytic Degradation Of Methyl Orange Research Articles

Eco-friendly synthesis of N- cholyl mercapto histidine capped silver nanoparticles and its sensing of mercury (II) ions and photo catalytic degradation of methyl orange

In this report, we have developed highly water soluble and stable silver nanoparticles (Ag NPs) utilizing N-Cholyl Mercapto Histidine (NCMH) as a reducing and stabilizing agent with near the primary critical micellar concentration (CMC) under ambient sunlight irradiation. Moreover, The NCMH was firstly synthesized by demonstrating the reaction between cholic acid and 2- Mercapto Histidine through a simple acid amine coupling approach. The primary and secondary CMC of NCMH surfactant was measured by pyrene (1 × 10−6 M) as a fluorescent probe, and values were found to be 3.2 and 13.1 mM respectively. The synthesized Ag NPs showed at neutral pH and highly stable for more than one year without any noticeable aggregation. The TEM analysis displays the synthesized Ag NPs having a spherical shape and average size of 9.6 ± 0.5 nm. The synthesis of stabilized Ag NPs was used for ultra-sensitive and selective detection of Hg2+ ions in aqueous medium were monitored by Uv–visible spectrometer and naked eyes with a lowest limit of detection (LOD) 7 nM. The photo-catalytic degradation of methyl orange (MO) by utilizing Ag NPs as nano-catalyst exhibits a potential degradation within a study period of 180 min. Concluding that, facile and cost effective green synthesis of NCMH capped Ag NPs possess excellent reducing ability towards the selective detection of Hg2+ ions along with photo-catalytic degradation of MO dye. These true findings detached an innovative pathway of Ag NPs towards the reactivity against the catalytic activity of dye degradation and selective sensing of Hg2+ ions. Thus it paves the way for extensive range of novel potential applications of Ag NPs in various environment friendly approaches of sensitive and analytical protocol in the future.

Oxidovanadium(IV) Salicylidene Glycine Complex with Phenanthroline as Co-ligand: Synthesis, Characterization, and Catalytic Degradation of Methyl Orange with H2O2

Oxidovanadium(IV) Salicylidene Glycine Complex with Phenanthroline as Co-ligand: Synthesis, Characterization, and Catalytic Degradation of Methyl Orange with H2O2

Efficient Catalytic Degradation of Methyl Orange by Various ZnO-Doped Lignin-Based Carbons.

Herein, a series of ZnO-doped lignin-based carbons (LC/ZnO) were successfully prepared from different types of lignin and used for methyl orange (MO) photocatalytic degradation. The apparent morphology, internal structure, and photoelectric properties of prepared LC/ZnO composites and their effects on subsequent MO photocatalytic degradation were investigated by various characterization techniques. The results showed that the LC/ZnO composites that were prepared in this work mainly consisted of highly dispersed ZnO nanoparticles and lignin-based carbon nano-sheets, which were beneficial for subsequent photogenerated electrons and holes formation, dispersion, and migration. The MO could be significantly degraded with various ZnO-doped lignin-based carbons, especially over the LCSL/ZnO, and the maximum degradation rate was 96.9% within 30 min under the simulated 300w sunlight exposure. The experiments of free radical elimination showed that the photocatalytic degradation of MO over LC/ZnO were a result of the co-action of multiple free radicals, and h+ might play the predominant roles in MO degradation. In addition, the pH of the solution had little effect on MO degradation, and the MO could be effectively degraded even in an alkaline solution of pH = 12.0. The cycling experiments showed that the prepared LC/ZnO had a good stability for MO photodegradation, especially for LCSL/ZnO, even after 5 times recycling, and the degradation rate of MO only dropped from 97.0% to 93.0%. The research not only provided a fundamental theory for the efficient photocatalytic degradation of MO by LC/ZnO composites, but also offered a new insight into lignin valorization.

Synthesis, Crystal Structure, and Photocatalytic Properties of Two Isoreticular Ce(IV)-MOFs with an Infinite Rod-Shaped Inorganic Building Unit.

The use of the V-shaped linker molecules 4,4'-oxydibenzoic acid (H2ODB) and 4,4'-carbonyldibenzoic acid (H2CDB) led to the discovery of two isoreticular Ce(IV)-based metal-organic frameworks (MOFs) of composition [CeO(H2O)(L)], L = ODB2-, CDB2-, denoted CAU-58 (CAU = Christian-Albrechts-University). The recently developed Ce-MOF synthesis approach in acetonitrile as the solvent proved effective in accessing Ce(IV)-MOF structures with infinite rod-shaped inorganic building units (IBUs) and circumventing the formation of the predominantly observed hexanuclear [Ce6O8] cluster. For the structure determination of the isoreticular MOFs, three-dimensional electron diffraction (3D ED) and powder X-ray diffraction (PXRD) data were used in combination with density functional theory (DFT) calculations. [CeO(H2O)(CDB)] shows reversible H2O adsorption by stirring in water and thermal treatment at 190 °C, which leads to a unit cell volume change of 11%. The MOFs feature high thermal stabilities (T > 290 °C), which exceed those of most Ce(IV)-MOFs and can be attributed to the infinite rod-shaped IBU. Surface and bulk oxidation states of the cerium ions were analyzed via X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge spectroscopy (XANES). While Ce(III) ions are observed by the highly surface-sensitive XPS method, the bulk material contains predominantly Ce(IV) ions according to XANES. Application of the MOFs as catalysts for the catalytic degradation of methyl orange in aqueous solutions was also studied. While degradation activity for both MOFs was observed, only CAU-58-ODB revealed enhanced photocatalytic activity under ultraviolet (UV) light. The photocatalytic mechanism likely involves a ligand-to-metal charge transfer (LMCT) from the linkers to the Ce(IV) centers. Analyses by XANES and inductively coupled plasma-optical emission spectroscopy (ICP-OES) demonstrate that leaching of Cerium ions as well as partial reduction of Ce(IV) to Ce(III) takes place during catalysis. At the same time, PXRD data confirm the structural stability of the remaining MOF catalysts.

Fenton-like degradation of methyl orange over CeO2 loaded on porous Al2O3: Catalyst preparation, efficiency and mechanism

In this work, the CeO2/Al2O3 composites were prepared by in situ growth method and developed as the heterogeneous Fenton-like catalyst for efficiently catalytic degradation of methyl orange (MO). Porous Al2O3 was firstly prepared by an evaporation-sintering method, and then the CeO2/Al2O3 composites were constructed by the in situ growth of CeO2 onto porous Al2O3. The phases and morphologies of the porous Al2O3 and CeO2/Al2O3 composites were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and specific surface area and pore size analyzer. The results indicated that the higher amount of the porogenic agent (NH4Cl) could make the specific surface area of porous Al2O3 larger and the Fenton-like reaction efficiency of CeO2/Al2O3 better. Free radical trapping experiments showed that the singlet oxygen (1O2) was the main reactive oxygen species responsible for the MO degradation. Finally, the possible mechanism of the Fenton-like reaction catalyzed by CeO2/Al2O3 was proposed and discussed.

A facile synthesis of K3PMo12O40/WO3 crystals for effective sonocatalytic performance.

Proper treatment of hazardous contaminants in the air, land, and water is crucial to environmental remediation. Sonocatalysis, by using ultrasound and suitable catalysts, has shown its potential in organic pollutant removal. In this work, K3PMo12O40/WO3 sonocatalysts were fabricated via a facile solution method at room temperature. Techniques such as powder X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy, and X-ray photoelectron spectroscopy were used to characterize the structure and morphology of the products. By using the K3PMo12O40/WO3 sonocatalyst, an ultrasound-assisted advanced oxidation process has been developed for the catalytic degradation of methyl orange and acid red 88. Almost all dyes were degraded within 120 min of ultrasound baths, proving that the K3PMo12O40/WO3 sonocatalyst has the advantage of speeding up the decomposition of contaminants. The impacts of key parameters, including catalyst dosage, dye concentration, dye pH, and ultrasonic power were evaluated to understand and reach optimized conditions in sonocatalysis. The remarkable performance of K3PMo12O40/WO3 in the sonocatalytic degradation of pollutants provides a new strategy for the application of K3PMo12O40 in sonocatalysis.

Catalytic degradation of methyl orange using bimetallic nanoparticles loaded into poly(N-isopropylmethacrylamide) microgels

The health of living organisms is greatly endangered by the rising concentration of hazardous substances in water, such as organic dyes. A catalytic system containing bimetallic nanoparticles loaded in polymer microgels was designed to degrade the organic dyes in aqueous medium. First, the poly( N -isopropylmethacrylamide) [P(NM)] microgel particles were synthesized using free radical precipitation polymerization method, and then Ag/Co nanoparticles were incorporated into the crosslinked network of P(NM) using the in-situ reduction via NaBH 4 . The P(NM) microgels and Ag/Co nanoparticles encapsulated in P(NM) microgels were characterized by TGA, FTIR, EDX, UV-Vis. and STEM results. The catalytic efficiency of Ag/Co-P(NM) towards degradation of methyl orange (MeOr) was evaluated under various reaction conditions. It was found that Ag/Co-P(NM) had remarkable catalytic efficiency. The catalytic efficiency of Ag/Co-P(NM) was found to be 90% even after recycling process. • The silver and cobalt nanoparticles loaded into microgels have been synthesized successfully. • Catalytic activity of metal nanoparticles loaded microgels were also studied in detail. • pH responsive behavior of hybrid microgels was also studied. • Catalytic efficiency of Ag/Co nanoparticles loaded microgels was observed after recycling.

Catalytic Degradation of Anionic Organic Dye on Greenly Synthesized CuO/ZnO Nanocomposites

CuO/ZnO nanocomposites were greenly prepared and tested for the catalytic degradation of methyl orange. The XRD analysis confirmed the existence of CuO and ZnO with crystallite sizes within the range of 15–30 nm. TEM and SEM images showed different morphological properties. The TGA analysis revealed a good thermal stability of the nanocomposite, with a total loss of less than 18% at a temperature of 700 °C. The nanocomposites were tested for the catalytic degradation of methyl orange under mild conditions with a catalyst mass/wastewater volume of 10 g/3 L, an initial dye concentration of 40 ppm, a pH of 4.5, and a degradation time of 3 h. The best efficiency of 49.1% was achieved by CuO nanoparticles (C), followed by 47.6%, which was obtained by 1C1Z. The degradation efficiency of ZnO (Z) was 16.4%, and it was increased by increasing the CuO precursor in the synthesis mixture, while adding ZnO to the CuO, resulting in a decrease in its catalytic performance.

Catalytic degradation of MO and MB dyes under solar and UV light irradiation using ZnO fabricated using Syzygium Cumini leaf extract

Abstract Zinc oxide nanoparticles (ZnO NPs) were fabricated using Syzygium cumini leave extract as a reducing and capping agent. The ZnO NPs were characterized using various techniques including scanning electron microscopy, UV-Visible and energy dispersive X-ray (EDX) techniques. The ZnO nanoparticles size was in 0.2–1 µm range and spherical in shape. Photocatalytic efficiency of ZnO NPs for the removal of MB (methylene blue) and MO (methyl orange) was investigated under solar and UV light expire. Photocatalytic efficiency of ZnO NPs was promising, which was found to be high under UV irradiation versus solar light. The ZnO NPs was confirmed as appropriate photocatalytic agent with significant potential for the removal of dye from wastewater.

Preparation of BiOClxBryIz Composite Catalysts and Its Visible Light Catalytic Degradation of Methyl Orange

Preparation of BiOClxBryIz Composite Catalysts and Its Visible Light Catalytic Degradation of Methyl Orange

Coordination and space confined preparation of nickel sub-nanoparticles within a metal-organic framework for catalytic degradation of methyl orange

Nickel nanoparticles are a kind of promising heterogeneous catalysts. However, highly dispersed Ni sub-nano particles (SNPs) encapsulated in carbon composites are rarely reported due to their tendency to aggregate and the lack of strong interactions between Ni2+ precursors and carbon materials. In this work, we present a facile coordination-space confinement strategy to prepare Ni SNPs@carbon composites by using a metal organic framework of UiO-67-NN as support. Utilizing the coordination interaction between Ni2+ ions and 2,2′-bipyridine-5,5′-dicarboxylate (NN-bpdc) ligands from the supports, the impregnated Ni2+ ions were stoichiometrically fixed and then in-situ transferred into NiO SNPs in the first pyrolysis process. Owing the space-confinement of UiO-67-NN, these NiO SNPs were then in-situ reduced into Ni SNPs with the size around 1∼2 nm, which were uniformly dispersed in the carbon composite derived from UiO-67-NN. Detailed studies revealed that the coordination-space confinement also played a vital role in the in-situ pyrolysis process of Ni2+→ NiO → Ni0. The degradation percentage of methyl orange dye in the presence of Ni@UiO-67-NN-P composite was higher than those reference catalysts prepared in conditions without either coordination or space confinement. The present work provides a potential strategy for the preparation of metallic SNPs catalysts with high efficiency.

Enhanced visible light photocatalytic activity of Fe2O3 modified TiO2 prepared by atomic layer deposition

In this work, commercial anatase TiO2 powders were modified using ultrathin Fe2O3 layer by atomic layer deposition (ALD). The ultrathin Fe2O3 coating having small bandgap of 2.20 eV can increase the visible light absorption of TiO2 supports, at the meantime, Fe2O3/TiO2 heterojunction can effectively improve the lifetime of photogenerated electron–hole pairs. Results of ALD Fe2O3 modified TiO2 catalyst, therefore, showed great visible light driven catalytic degradation of methyl orange compared to pristine TiO2. A 400 cycles of ALD Fe2O3 (~ 2.6 nm) coated TiO2 powders exhibit the highest degradation efficiency of 97.4% in 90 min, much higher than pristine TiO2 powders of only 12.5%. Moreover, an ultrathin ALD Al2O3 (~ 2 nm) was able to improve the stability of Fe2O3-TiO2 catalyst. These results demonstrate that ALD surface modification with ultrathin coating is an extremely powerful route for the applications in constructing efficient and stable photocatalysts.

Enhanced photo catalytic degradation of methyl orange using p–n Co3O4-TiO2 hetero-junction as catalyst

Abstract Photo catalytic degradation of pollutants is one of the techniques used for treatment of dye contaminated wastewater. TiO2 has attracted much attention as photo catalyst for treatment of contaminated water. In this study, the photo catalytic performance of TiO2 has been enhanced by formation of p–n Co3O4-TiO2 hetero-junction. The p–n Co3O4-TiO2 hetero-junction was prepared by wet incipient impregnation method and characterized by various techniques. The photo catalytic activity of prepared composite was evaluated by photo degradation of methyl orange. The as prepared Co3O4-TiO2 composite was found as effective catalyst than Co3O4 and TiO2. The higher photo catalytic activity was attributed to p–n junction formed between Co3O4 and TiO2. The degradation data was analyzed according to Eley–Rideal mechanism in terms of 1st and 2nd order kinetics.

Valorization of Pichia spent medium via one-pot synthesis of biocompatible silver nanoparticles with potent antioxidant, antimicrobial, tyrosinase inhibitory and reusable catalytic activities.

The purpose of this study was to determine the feasibility of a novel biogenic synthesis of silver nanoparticles using Pichia pastoris spent medium - a major waste product from heterologous protein expression as the sole reducing and capping agent, with potential biological, antimicrobial and wastewater remediation applications. Using UV-vis spectroscopy, TEM, XRD, EDX, FTIR, SEM we demonstrated the successful bio-fabrication of Pichia spent medium encapsulated silver nanoparticles (PSM-AgNPs). PSM-AgNPs displayed substantial antiradical activity against DPPH and ABTS. The antiradical activity against ABTS was similar to that of the control, ascorbic acid. PSM-AgNPs also revealed potent anti-tyrosinase and antibacterial activity against some common foodborne pathogenic microbes. Human erythrocyte hemolytic and embryonic colon Caco-2 cell viability assays suggest that PSM-AgNPs was biocompatible. In addition, PSM-AgNPs, was also effective in the catalytic degradation of methyl orange and Congo red dyes with pseudo first order rate constants of 0.2301min-1 and 4.7×10-3s-1, respectively. These results present a clean, convenient, and inexpensive approach for the biosynthesis of silver nanoparticles with potential implications in the eco-friendly, safe and effective utilization of waste culture media, mitigation of pathogenic bacteria and management of industrial effluents.

Fabrication of ultralight 3D graphene/Pt aerogel via in situ gamma-ray irradiation and its application for the catalytic degradation of methyl orange

In this work, we reported a facile and environmentally friendly approach for the preparing of 3D graphene/Pt aerogel by gamma irradiation at room temperature. Graphene oxide (GO) and platinum ion are simultaneously reduced and self-assembled into a three-dimensional (3D) macro porous structure. Pt NPs with diameter between 2.3 and 5.5 nm were homogeneously attached onto the graphene sheets of the 3D network structure. The catalytic efficiency towards the degradation of methyl orange (MO) of the 3D GA/Pt composite is 108 times higher than that of the pure Pt NPs under the same experimental conditions.

Synthesis of Active MFe2O4/γ-Fe2O3 Nanocomposites (Metal = Ni or Co) for Reduction of Nitro-Containing Pollutants and Methyl Orange Degradation

Metal-ferrite/maghemite nanocomposites (NiFe2O4/***[Formula: see text]-Fe2O3 and CoFe2O4/[Formula: see text]-Fe2O[Formula: see text] were synthesized via doping maghemite with metal salt (NiCl2 or CoCl[Formula: see text] followed by reduction of metal ions using NaBH4. The synthesized metal-ferrite/maghemite nanocomposites were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), Fourier transform infrared (FTIR) and the amounts of the dopant-metal (Ni/Co) were determined using ICP-OES technique. Results showed that this synthetic route produced nanocomposites with highly active ferrite phases MFe2O4. The synthesized nanocomposites exhibited exceptional catalytic activities for the reduction of 4-nitrophenol and 2-nitroaniline as well as the catalytic degradation of methyl orange. Specific activity parameter of NiFe2O4/[Formula: see text]-Fe2O3 and CoFe2O4/[Formula: see text]-Fe2O3 toward reduction of 4-NP reached 993.9 and 929.8[Formula: see text]s[Formula: see text][Formula: see text]g[Formula: see text], respectively. These high values of specific activities are higher than most reported metal-ferrite composites prepared via traditional co-precipitation methods. Besides, strong magnetic properties of the prepared metal-ferrite/maghemites facilitates easy separation process for several reuses.

Comparative Study on the Catalytic Degradation of Methyl Orange by Silver Nanoparticles Synthesized by Solution Combustion and Green Synthesis Method

Nanosized silver nanoparticle (Ag-NP) powder has been synthesized using solution combustion synthesis method and green biological reduction method. The percentage yield and purity inspection of the synthesized powder was performed and compared by UV–Vis, XRD and SEM. Catalytic activities of the synthesized Ag nanoparticles toward methyl orange dye degradation in the presence of NaBH4 are analyzed and have been compared in terms of percentage reduction, reaction time and apparent reaction rate. Silver nanoparticles synthesized by solution combustion synthesis method showed 94% catalytic degradation and a rate of 0.0725 min−1. The apparent kinetic rate of silver nanoparticles synthesized by solution combustion synthesis method was found to be twelve times faster than that of silver nanoparticles synthesized by green synthesis method.

Two New Sandwich‐Type Phosphomolybdates: Thermal Decomposition and Photocatalytic Degradation Behavior of a UV‐Excited Solid‐Phase Fenton Catalyst

Although classical homogeneous Fenton reaction systems (FeII + H2O2) are widely used for organic pollutant degradation, this technology has important shortcomings such as waste generation and difficult Fe2+ recycling. These shortcomings originate secondary pollution issues and make it difficult to control the reactions. Polyoxometalates (POMs) are characterized by bearing large electron‐donating conjugate systems able to stabilize Fe2+. To explore a new kind of heterogeneous Fenton reagent, we prepared a new‐type of stable heterogeneous Fenton reagent, (H3O)3.5(H3DETA)3.5{FeII[H4MoV6O15(PO4)4]2} (DETA = diethylenetriamine) (1) by inserting FeII into the POMs. The sandwich‐type 1 was excited by ultraviolet (UV) light, showed high efficiency as a solid‐phase Fenton catalyst, and can be potentially recycled to control the reactions. The coordinating reaction mechanisms for the catalytic degradation of methyl orange (MO) over the 1 + H2O2 reaction system was studied, including photocatalysis and Fenton oxidation effects. As a contrast, another new phosphomolybdate, (H3DETA)4{ZnII[H5MoV6O15(PO4)4]2}·7.5H2O (2), which has the same sandwich‐type polyanion but ZnII acting as the sandwich‐atom, has also been synthesized, characterized. The comparative study of photocatalytically degrading MO has also been carried out. In addition, by studying the thermal decomposition behavior of 1, we revealed, for the first time, the presence of Mo4P3 as a decomposition residue of 1.

Enhanced photo-Fenton degradation performance over multi-metal co-supported SAPO-18 zeolites by promoted active species yield

Fe, Mn co-supported SAPO-18 zeolite was synthesized via ion-exchange method and exhibited high performance in catalytic degradation of methyl orange (MO). The bimetallic Fe-Mn/SAPO-18 catalyst showed almost 100% MO (50 mg/L) removal within 20 min, which was superior to the MO degradation efficiency over monometallic Fe or Mn catalysts. The hydroxyl group (OH) generated in the photo-Fenton catalysis was determined by fluorescence probe and the corresponding reaction mechanism was explored. We proposed that the light and synergistic effect of bimetal promote the conversion of metal ion valence, thereby enhancing the generation of the active species and the degradation efficiency of MO. Furthermore, the influences of some essential factors on MO degradation rate were investigated. The results indicated that the pH of the solution plays an important role in Fenton degradation of MO. 100% MO degradation is achieved within 10 min when the initial pH is set at 2–3 under UV for Fe-Mn/SAPO-18. Moreover, it also shows good performance under neutral conditions, thus exhibits considerable activity at expanded pH range. And the concentrations of H2O2 and MO solution and the dosage of catalysts can influence the degradation rate of dyes. This work not only made significant progress on the development of high-performance catalysts for the degradation of MO, but also provided a direction for the study of organic contaminant degradation.

Functional Janus Particles Modified with Ionic Liquids for Dye Degradation

Snowman-like silica@PDVB/PS Janus particles were fabricated via seeded emulsion polymerization and modified with hydrophilic ionic liquid moieties. The Janus particles can readily be further modified by incorporating new functionalities through simple anion exchange. PW12O403– as a catalytically active species for dye degradation was introduced into the Janus particles, and the performance in the catalytic degradation of methyl orange was evaluated.