Methyl Orange Solution Research Articles

Elimination of synthetic dyes by clamshell derived photo-active hydroxyapatite

Herein, a novel designed hydroxyapatite (HAp) derived from freshly calcined clamshell waste through the wet precipitation method was synthesized. HAp has been developed as a heterogeneous photocatalyst for the anionic dye methyl orange (MO) degradation. The pH on synthesizing HAp was varied in basic conditions. The results show HAp formed at pH more than 10. The MO photodegradation was done under UV-light irradiation for 120 min. HAp catalyst showed the optimum MO degradation efficiency using rod-like structure HAp synthesized at pH 12. HAp with optimum photodegradation efficiency was optimized for the catalyst loading and the pH of the MO solution. MO at pH 6 with 0.05 g catalyst loading showed the highest degradation efficiency around 97 % using HAp prepared at pH 12 with band gap at 4.990 eV. This finding brings a new insight on natural sources materials as photo-active in sustainable of persistent water pollutants.

The Synthesis of Ag/TiO2 via the DC Magnetron Sputtering Method and Its Application in the Photocatalytic Degradation of Methyl Orange in Na2SO4 Solution

TiO2 and TiO2 films modified with Ag (Ag/TiO2) were prepared via the DC magnetron sputtering method and the degree of modification was controlled via the sputtering power and time of Ag. The microstructures and properties of these films were characterized using field emission scanning electron microscopy, X-ray diffractometry, ultraviolet–visible diffuse reflectance spectrometry, atomic force microscopy, and X-ray photoelectron spectroscopy (XPS). The results show that the prepared films have an anatase structure. Compared with pure TiO2, Ag deposition can improve the utilization of light. The three-dimensional images of Ag/TiO2 clearly show that with the increase in Ag sputtering power and sputtering time, Ag particles on the surface of the film gradually increase, and the structure of the film is relatively dense. The photocatalytic effect of Ag/TiO2 films is the best when the Ag sputtering power is 5 W and the sputtering time is 50 s. Under high-pressure mercury lamp irradiation, the photocatalytic degradation rate of methyl orange (MO) in pure MO solution with Ag/TiO2-5 W-50 s can reach 100% within 55 min, whereas that in MO-Na2SO4 mixed solution can reach 99.55% within 65 min. The results suggest that the presence of Na2SO4 in MO solution can inhibit the degradation of MO using Ag/TiO2, the result of XPS suggests that Na2SO4 accelerates the oxidation of Ag, which may lead to an increase in the recombination rate of photogenerated electron–hole pairs and a decrease in the degradation rate. During the process of recycling photocatalysts, the degradation rate of MO was apparently reduced. A possible reason is that the Ag particles have been oxidized and products of photocatalytic degradation are on the surface of the photocatalyst. The photocatalytic degradation mechanism was studied.

Preparation of DyVO4 by Sol-Gel Method and Research of Its Photocatalytic Activity

Using dysprosium oxide (Dy2O3), ammonium metavanadate (NH4VO3), nitric acid (HNO3) and citric acid (C6H8O7·H2O) as main raw materials, DyVO4 was successfully prepared by sol-gel method. DyVO4 samples were characterized by thermogravimetry differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), scanning electron microscope (SEM), diffuse reflectance spectrum (DRS) and Fourier transform infrared spectroscopy (FT-IR). Under condition of ultraviolet light, taking 10 mg/L methyl orange solution as simulated sewage, the effects of synthesis temperature and illumination time on the photocatalytic activity of DyVO4 were studied. The results show that pure tetragonal zircon DyVO4 samples can be obtained under calcination conditions of 600 °C to 900 °C. The average grain size is about 2 μm and the breadth of band gap is about 3.52 eV. The sample prepared at 800 °C has the best photocatalytic activity. Under ultraviolet light illumination for 150 min, the degradation rate of 10 mg/L methyl orange can reach nearly 100% in presence DyVO4. DyVO4 prepared by sol-gel method is a photocatalyst which has broad application prospect.

Preparation of TiO2 composite photocatalyst using amorphous SiO2 microspheres loaded with spent SCR catalysts

The products of S-SCR grinding and alkali treatment (S-SCR-T, primarily consisting of anatase TiO2 with a size less than 20 nm) were utilized as photocatalysts, while SiO2 microspheres (MS-SiO2) were used as carriers. A TiO2 composite photocatalyst (M-Si/SR-Ti) was prepared by wet mechanical grinding. The results demonstrate that in M-Si/SR-Ti, S-SCR-T was uniformly loaded on the MS-SiO2 surface in a well-dispersed state and firmly bonded at the interface with Si–O–Ti bonds. M-Si/SR-Ti prepared under optimized conditions exhibited excellent photocatalytic degradation and recycling properties for methyl orange. The degradation rate of methyl orange solution at 10 ppm for 60 min under UV irradiation was 97%, which was comparable to that of S-SCR-T, and remained unchanged after four cycles of recycling. Compared with S-SCR-T, M-Si/SR-Ti exhibited significantly improved settlement recovery performance in water. The loading of S-SCR-T on the MS-SiO2 surface, which increased the exposure of the nano-TiO2 active site and decreased the energy gap, was the mechanism responsible for improving the photocatalytic performance of M-Si/SR-Ti. This study positively impacted the effort to efficiently utilize and increase the value of S-SCR and reduce the cost of the photocatalyst.

Evaluation of the Adsorptive Performance of Rambutan-shaped γ-Al2O3 Micro-nanostructure against Wastewater Containing the Azo Dye: Methyl Orange

Aim: The aim of this study is to explore and evaluate the possibility of rambutan-shaped micro-nanostructured γ-Al2O3 material’s usage as an adsorbent in industrial wastewater processing. Background: Every year, more than 7 million tons of dyestuff-containing wastewater are produced in the industry. Although there are many adsorbents like fly ash and clays, the shortages limit their actual applications. It is still necessary to find a new cheaper adsorbent. Objective: The paper aimed to investigate the adsorption capacity and decolorization ability of rambutan- shaped γ-Al2O3 material synthesized via a composite soft template method. Methods: The rambutan-shaped γ-Al2O3 material was prepared and characterized via XRD, TEM, FE-SEM, and FT-IR (See our group’s published article in “Ming Shen*, et al., Acta Phys.-Chim. Sin. 2013, 29 (10), 2286-2294”). The methyl orange aqueous solution was selected as the model of industrial wastewater. The methyl orange solution (15.0 mg·L-1) with different pH (2~9) was exposed to a series of amounts of γ-Al2O3 powder ranging from 10.0 to 70.0 mg. Different concentrations of methyl orange solution, ranging from 5.0 to 200.0 mg·L-1 were also tested with the same amount of γ-Al2O3 powder (50.0 mg). The adsorption-calcination cycle analysis was performed with methyl orange solution (50.0 mg·L-1) and 500.0 mg of γ-Al2O3 powder at pH=3. Results: The γ-Al2O3 material exhibits excellent adsorption capacity (114.10 mg·g-1) towards acidic methyl orange aqueous solution. At the same time, the decolorization rate of the γ-Al2O3 material reaches about 88%. This material still keeps a 50% decolorization rate after 6 repeats of the adsorption- calcination cycle. Moreover, the excellent self-sedimentation ability of this material also provides an easy separation for future industrial applications. Conclusion: The γ-Al2O3 material with rambutan-like micro-nanostructure presents excellent adsorption capacity/decolorization ability and self-sedimentation ability. It can be used as a new type of adsorbent for wastewater processing. The rambutan-shaped micro-nanostructure plays an important role in maintaining the adsorption ability of the γ-Al2O3 material.

Nanoporous Au Behavior in Methyl Orange Solutions.

Nanoporous (NP) gold, the most extensively studied and efficient NP metal, possesses exceptional properties that make it highly attractive for advanced technological applications. Notably, its remarkable catalytic properties in various significant reactions hold enormous potential. However, the exploration of its catalytic activity in the degradation of water pollutants remains limited. Nevertheless, previous research has reported the catalytic activity of NP Au in the degradation of methyl orange (MO), a toxic azo dye commonly found in water. This study aims to investigate the behavior of nanoporous gold in MO solutions using UV-Vis absorption spectroscopy and high-performance liquid chromatography. The NP Au was prepared by chemical removal of silver atoms of an AuAg precursor alloy prepared by ball milling. Immersion tests were conducted on both pellets and powders of NP Au, followed by examination of the residual solutions. Additionally, X-ray photoelectron spectroscopy and electrochemical impedance measurements were employed to analyze NP Au after the tests. The findings reveal that the predominant and faster process involves the partially reversible adsorption of MO onto NP Au, while the catalytic degradation of the dye plays a secondary and slower role in this system.

Enhanced Photocatalytic and Filtration Performance of TiO2-Ag Composite-Coated Membrane Used for the Separation of Oil Emulsions

Polyvinylidene fluoride (PVDF) membranes were coated with TiO2 and TiO2-Ag to enhance their efficiency for oil-in-water emulsion separation. The photocatalytic activities of the two modified membranes and their filtration performances were compared in detail. The significantly enhanced photocatalytic activity of the TiO2-Ag composite was proved using a methyl orange (MO) solution (c = 10−5 M) and a crude oil emulsion (c = 50 mg·L−1). The TiO2-Ag-coated membrane reduced the MO concentration by 87%, whereas the TiO2-modified membrane reached only a 46% decomposition. The photocatalytic reduction in the chemical oxygen demand of the emulsion was also ~50% higher using the TiO2-Ag-coated membrane compared to that of the TiO2-coated membrane. The photoluminescence measurements demonstrated a reduced electron/hole recombination, achieved by the Ag nanoparticle addition (TiO2-Ag), which also explained the enhanced photocatalytic activity. A significant improvement in the oil separation performance with the TiO2-Ag-coated membrane was also demonstrated: a substantial increase in the flux and flux recovery ratio (up to 92.4%) was achieved, together with a notable reduction in the flux decay ratio and the irreversible filtration resistance. Furthermore, the purification efficiency was also enhanced (achieving 98.5% and 99.9% COD and turbidity reductions, respectively). Contact angle, zeta potential, scanning electron microscopy (SEM), and atomic force microscopy (AFM) measurements were carried out to explain the results. SEM and AFM images revealed that on the TiO2-Ag-coated membrane, a less aggregated, more continuous, homogeneous, and smoother nanolayer was formed due to the ~50% more negative zeta potential of the TiO2-Ag nanocomposite compared to that of the TiO2. In summary, via Ag addition, a sufficiently hydrophilic, beneficially negatively charged, and homogeneous TiO2-Ag-coated PVDF membrane surface was achieved, which resulted in the presented advantageous filtration properties beyond the photocatalytic activity enhancement.

A floating biosorbent of polylactide and carboxylated cellulose from biomass for effective removal of methylene blue from water

A floating adsorbent bead was prepared from polylactide (PLA) and maleic anhydride (MAH)-modified cellulose in a one-pot process (OP bead). Cellulose was extracted from waste lemongrass leaf (LGL) and modified with MAH in the presence of dimethylacetamide (DMAc). PLA was then added directly into the system to form sorbent beads by a phase separation process that reused unreacted MAH and DMAc as a pore former and a solvent, respectively. The chemical modification converted cellulose macrofibres (55.1 ± 31.5 μm) to microfibers (8.8 ± 1.5 μm) without the need for grinding. The OP beads exhibited more and larger surface pores and greater thermal stability than beads prepared conventionally. The OP beads also removed methylene blue (MB) more effectively, with a maximum adsorption capacity of 86.19 mg⋅g−1. The adsorption of MB on the OP bead fitted the pseudo-second order and the Langmuir isotherm models. The OP bead was reusable over five adsorption cycles, retaining 88 % of MB adsorption. In a mixed solution of MB and methyl orange (MO), the OP bead adsorbed 96 % of the cationic dye MB while repelling the anionic dye MO. The proposed method not only reduced time, energy and chemical consumption, but also enabled the fabrication of a green, effective and easy-to-use biosorbent.

Novel ceramic supports for catalyst with hierarchical pore structures fabricated via additive manufacturing-direct ink writing

The use of direct ink writing technology, combined with in-situ grown whiskers, has facilitated the development of 3D-printed ceramic catalyst supports-aluminum borate porous ceramics (ABPCs) with hierarchical pore structures. The optimal slurry consists of 0.2 wt% polycarboxylate, 19 wt% water addition, and 1.2 wt% sodium alginate. The most effective printing parameters are determined to be a 1.0 mm nozzle diameter, 10 mm/s printing speed, 4.0 kPa air pressure, and 0.4 mm layer height. After sintering at 1100 ℃, pure-phase aluminum borate (Al18B4O33) ceramics are achieved, leading to the formation of needle-like aluminum borate whiskers. The aspect ratio of whiskers, flexural strength, BET-specific surface area, and photocatalytic activity of ABPCs increase initially and then decrease with increasing sintering temperature. The ABPCs coated with a titanium oxide layer display a photocatalytic degradation rate of 83.92% for methyl orange solution. These results underscore the immense potential of ABPCs in high-temperature catalyst support applications.

Synthesis and application of natural asphalt sulfonic acid (NA-SO3H) as a novel and reusable carbonaceous super adsorbent for rapid decolorization of aqueous dye solutions

This research involves functionalizing solid natural asphalt through sulfonation in the presence of H2SO4. The resulting product, known as mildly sulfonated natural asphalt sulfonic acid (ms-NA-SO3H), was investigated and confirmed by SEM, DRS, EDX, BET, CHNOS, and FT-IR analyses. The FT-IR spectrum of ms-NA-SO3H displays distinctive absorption peaks related to the presence of asymmetric and symmetric stretching modes of SO2, which are associated with SO vibrations. These findings confirm the successful sulfonation of natural asphalt. The SEM images illustrated that the surface of natural asphalt appears relatively smooth, with minimal porosity except for occasional cracks. Conversely, the external surface of the ms-NA-SO3H adsorbent exhibits irregular pores, compared to natural asphalt. In the next step, the porous heterogeneous bituminous has been used for the decolorization of methylene blue, and methyl orange solutions. Variation of removal percent versus dye concentration showed functionalization surface groups of natural asphalt with SO3H groups have provided high activated sites for color removal from the aqueous environment. Various parameters such as solution pH, contact time, adsorbent dosage, and initial dye concentration, were examined. The results of surface adsorption analysis at different concentrations revealed that the adsorption behavior on the adsorbent could be accurately described by the Langmuir isotherm and the pseudo-second-order kinetic model. The rapid removal and high adsorption capacity of the modified asphalt indicate its efficiency in the surface adsorption processes. The reusability of the ms-NA-SO3H adsorbent was studied via a physical adsorption mechanism, using ethanol or dimethyl formamide. Obtained results showed the prepared modified asphalt is a simple, efficient, cost-effective, and environmentally friendly candidate for different pollution removal.

Increasing photocatalytic activity of magnetite NPs with the inclusion of methyl orange and Evans blue functional groups in the photoactivation of acid sites

In this paper, The photocatalytic reactions of methyl orange (MO) and Evans Blue (EB) are conducted on four distinct magnetite nanoparticles (NPs) samples. This study investigates, for the first time in literature, the impact of the inclusion of chromophores and auxochromes in the photoactivation of Brönsted and Lewis’s acid sites on the photocatalytic activity. In so doing, free functional groups of MO and EB that are not photodegraded have been analyzed using FTIR spectroscopy. This analysis leads to infer photoactivated acid site densities. FTIR analysis of initial residual solutions of MO and EB revealed lower contents of free functional groups of EB compared to MO. Based on this finding, it would be expected that EB would demonstrate better photodegradation due to the lower contents of its functional groups. However, the obtained results contradicted this assumption, indicating an opposite behavior. Moreover, FTIR analysis of final residual solutions revealed that functional groups of MO were highly photodegraded compared to EB. Also, calculated MO photodegradation capacities, yields, and kinetics constants were found to be higher than those of EB. This suggests that parameters other than band gap energy may control the photoactivation of Brönsted and Lewis’s acid sites and thus photocatalytic activity. Indeed, functional groups are involved in increasing the photocatalytic activity. The higher contents of MO functional groups lead to better increasing the photocatalytic activity of magnetite NPs.

Facile synthesis of lignin-based Fe-MOF for fast adsorption of methyl orange

To rapidly remove dyes from wastewater, iron-based metal–organic frameworks modified with phenolated lignin (NH2-MIL@L) were prepared by a one-step hydrothermal method. Analyses of the chemical structure and adsorption mechanism of the NH2-MIL@L proved the successful introduction of lignin and the enhancement of its adsorption sites. Compared with NH2-MIL-101-Fe without phenolated lignin, the modification with lignin increased the methyl orange (MO) adsorption rate of NH2-MIL@L. For the best adsorbent, NH2-MIL@L4, the MO adsorption efficiency in MO solution reached 95.09% within 5 min. NH2-MIL@L4 reached adsorption equilibrium within 90 min, exhibiting an MO adsorption capacity of 195.31 mg/g. The process followed pseudo-second-order kinetics and the Dubinin-Radushkevich model. MO adsorption efficiency of NH2-MIL@L4 was maintained at 89.87% after six adsorption-desorption cycles. In mixed solutions of MO and methylene blue (MB), NH2-MIL@L4 achieved an MO adsorption of 94.02% at 5 min and reached MO adsorption equilibrium within 15 min with an MO adsorption capacity of 438.6 mg/g, while the MB adsorption equilibrium was established at 90 min with an MB adsorption rate and capacity of 95.60% and 481.34 mg/g, respectively. NH2-MIL@L4 sustained its excellent adsorption efficiency after six adsorption-desorption cycles (91.2% for MO and 93.4% for MB). The process of MO adsorption by NH2-MIL@L4 followed the Temkin model and pseudo-second-order kinetics, while MB adsorption followed the Dubinin-Radushkevich model and pseudo-second-order kinetics. Electrostatic interactions, π-π interactions, hydrogen bonding, and synergistic interactions affected the MO adsorption process of NH2-MIL@L4.

Green synthesis of gaharu leaf extract-modified magnetite as an adsorbent for methyl orange textile dyes

Magnetite, a widely synthesized compound utilized as an adsorbent in various processes, exhibits reduced adsorption efficiency due to aggregation in aqueous solutions. Addressing this limitation, modification of magnetite is necessary to mitigate agglomeration and enhance adsorption capacity. Herein, we propose the utilization of gaharu leaf extract for magnetite modification, leveraging its abundance as a byproduct of essential oil production and rich secondary metabolite content, which serves as a stabilizing agent in synthesis processes. Magnetite (M) and gaharu leaf extract-modified magnetite (MEDG) were synthesized and evaluated as adsorbents for methyl orange (MO) textile dyes. Characterization via FTIR, PSA, SEM-EDX, XRD, and VSM revealed distinctive features of MEDG, including vibrational peaks corresponding to organic functional groups derived from the secondary metabolites present in the gaharu leaf extract. These functional groups actively participate in the adsorption process and prevent magnetite aggregation. MEDG exhibited a particle size of 4408.7 nm, compared to 4625 nm for M, with both exhibiting face-centered cubic (fcc) crystal structures. Additionally, MEDG demonstrated a crystallinity percentage of 92.49 % and saturation magnetization of 34.43 emu/g, attributed to the incorporation of gaharu leaf extract. Adsorption studies demonstrated that MEDG and gaharu leaf simplicia (SDG) achieved maximal adsorption of MO at pH 3 for 60 min and pH 4 for 70 min, respectively, with an adsorption efficiency of 95–99 % for a 5 ppm MO solution. The adsorption kinetics followed Ho’s pseudo-second-order model, and the isotherm conformed to Freundlich’s model. Furthermore, M and MEDG exhibited high reusability, with up to 5 cycles of reuse, while SDG demonstrated 3 cycles. However, the adsorption efficiency decreased to 87 % for MEDG and 85.19 % for SDG upon the fifth repetition. In conclusion, modification of magnetite with gaharu leaf extract enhances its adsorption capacity, offering economic advantages over pure magnetite due to increased surface area andactivesites.

Degrade Methyl Orange by Combining Cu2O/Al2O3 and H2O2 as Catalyst

To efficiently degrade printing and dyeing wastewater at low costs, Cu2O/Al2O3 catalyst was prepared by electrochemical method. Under its combined action with H2O2, photocatalytic degradation of methyl orange solution, as simulated wastewater, was carried out. With the aid of X-ray diffractometer, X-ray microanalysis system and scanning electron microscope, the structure and composition of catalyst film were designed by adjusting the electrochemical parameters, and the performance of photocatalyst was evaluated by the degradation rate of methyl orange. It was found that after anodizing aluminum alloy for 2 h in a 2 mol/L H2SO4 solution under a voltage of 15 V, alumina film with reasonable pore size distribution could be prepared on the alloy surface. By electroplating the film in a 0.01 mol/L CuSO4 solution at 5°C, and then hydrothermally treating it at 200°C, the Cu2O/Al2O3 photocatalyst could be obtained. The prepared Cu2O/Al2O3 and 10% H2O2 were used jointly as photocatalyst to degrade 10 mg/L methyl orange solution for 480 min, which achieved a methyl orange degradation rate of up to 82.1%.

Novel ternary PPy–ZnFe2O4/fly ash-cenosphere photocatalysts for photodegradation of methyl orange under UV light

In this study, fly ash cenospheres (FACs), characterized by their floating properties and inherent photocatalytic activity, were used as a carrier to support ZnFe2O4 material and doped with conductive polymer polypyrrole (PPy) to prepare a novel ternary PPy–ZnFe2O4/FACs (PPy–ZF) composite catalyst. X-ray diffraction, Fourier transform infrared spectroscopy, TEM, and scanning electron microscopy were used to characterize the structure, morphology, and optical properties of the samples prepared. In particular, a 20 mg/L methyl orange (MO) solution at pH 4 was given 0.075 g of PPy–ZF catalyst to add, and after 30 min of dark adsorption, followed by irradiation for 180 min, 98.54% of the MO was removed. The material was also shown to have good stability and reusability through three cycles of use. Additionally, the material exhibited good photocatalytic activity for other dyes. The results of photocatalytic experiments showed their significantly enhanced photocatalytic activity toward MO, which was mainly attributed to the synergistic effect of PPy and ZnFe2O4 on the surface of FACs, leading to a high separation efficiency and a low rate of photogenerated charge complexation. In addition, cyclic tests demonstrated the stability and reusability of the composite. The leading role in the photocatalytic degradation of MO was demonstrated by the radical trapping experiment, which showed ·O2 − and h+. The present study can significantly improve the photocatalytic performance of the floating materials of ZnFe2O4/FACs, which is beneficial to solve the current energy crisis and environmental pollution problems. It has certain reference significance to solve the problems of environmental pollution, waste recycling, and catalyst recycling in the future.

Investigation of cluster magnetorheological electro-Fenton composite polishing process for single-crystal GaN wafer based on BBD experimental method

A cluster magnetorheological (MR) electro-Fenton composite polishing technique was proposed in this work, which can realize high efficiency, ultra-smooth and damage-free of GaN wafer by the synergistic effect of electro-Fenton reaction and flexible mechanical removal of MR polishing. The key parameters of electro-Fenton were optimized through methyl orange degradation experiments based on BBD experimental method. The results showed that the decolorization rate had a strong dependence on H2O2 concentration, Fe–C concentration and pH value, where the decolorization rate had the maximum value when the H2O2 concentration of 5 wt%, Fe–C concentration of 3 wt% and pH value of 3. Compared with the Fenton reaction, the decolorization and REDOX potential of methyl orange solution were significantly improved in the electro-Fenton reaction. Furthermore, the process parameters of the cluster MR electro-Fenton composite polishing were optimized to obtain the best polishing result, which was realized under the conditions of 3 wt% diamond (grain size: 0.5 µm), a polishing gap of 0.9 mm and a polishing time of 60 min. The novel method achieved a material removal rate of 10.79 μm h−1, which was much higher than that of the conventional technique. In addition, an ultra-smooth and damage-free surface with a roughness of 1.29 nm Ra was obtained.

Preparation and enhanced photocatalytic properties of Cu31S16/Cu9S5 heterojunction composite

A heterojunction photocatalytic material Cu31S16/Cu9S5 was successfully synthesized through a facile solvothermal method by controlling the reaction temperature. The phase composition, morphology, absorbance and surface area were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffusion reflection and Brunauer–Emmett–Teller (BET). Transient photocurrent response and electrochemical impedance spectroscopy (EIS) were measured to support the generation and transfer of the photoinduced charge carriers. The heterojunction Cu31S16/Cu9S5 showed superior separation efficiency of the photoinduced charge carriers. The photocatalytic performance of the Cu31S16/Cu9S5 was evaluated through degrading high-concentration methyl orange (MO) solution under visible light. The degradation rate of MO solution increased to 94.8% in 60 min, showing the most remarkable photocatalytic ability. Moreover, a probable photocatalytic mechanism of the Cu31S16/Cu9S5 was discussed.

Graphene Nanocomposites in the Treatment of Pancreatic Cancer

The application value of titanium dioxide (TiO2)/graphene nanocomposites in photothermal therapy of pancreatic cancer (PC) was explored. Using scale graphite as raw material, graphene was obtained by Hummer oxidation method and hydrazine hydrate reduction method, and then TiO2/graphene nanocomposites were prepared by ultrasonic heating. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and degraded methyl orange solution were adopted to detect the surface structure, particle size, element morphology, and photocatalytic activity under different composite ratios, different sonication times, and different heating temperatures. Human normal pancreatic ductal epithelial cell line HPDE6-C7 and human metastatic PC cell AsPC-1 were adopted as research models. The cytotoxicity of TiO2/graphene nanocomposites and the killing effect of photothermal therapy based on TiO2/graphene nanocomposites were analyzed by water soluble tetrazolium salt colorimetric assay (WST-1) and methyl thiazolyl tetrazolium salt colorimetric assay (MTT). The results suggested that when the ratio of graphene to TiO2 was 50:1, the ultrasonic time was 100 min, and the heating temperature was 200 °C, TiO2 was better attached to the surface of graphene, the distribution of particles was relatively more uniform, and the concentration of methyl orange was relatively lowest. The XRD pattern showed that the diffraction peak of the doped TiO2/graphene nanocomposite was basically the same as that of the pure TiO2. When the ultrasonic time was 100 min, the diffraction peak intensity in the XRD pattern was the largest. As for AsPC-1 cells, the cell viability was obviously lower than 0.1/1/10/100 μm/mL when the concentration of TiO2/graphene nanocomposites was 500 μm/mL (P <0.05). For HPDE6-C7 cells, when the concentration of TiO2/graphene nanocomposites was 100 and 500 μm/mL, the cell viability was obviously lower than 0.1/1/10 μm/mL (P <0.05), and 500 μm/mL was the lowest. The cell killing rate in group D was clearly higher as against groups A, B, and C (P <0.05). Graphene: The optimal preparation conditions of TiO2/graphene nanocomposites are 50:1, 100 min of ultrasound time, and 200 μC of composite temperature. The photothermal therapy based on TiO2/graphene nanocomposites can effectively kill PC cells, and has a good potential in the field of hyperthermia for pancreatic tumors.

Characterization and fabrication of p-Cu2O/n-CeO2 nanocomposite for the application of photocatalysis

Degradation of hazardous sewage from polluted water requires the application of nanomaterial’s into industrial wastewaters. For this problem, different noble nanomaterial (Cu2O, CeO2 and Cu2O/CeO2) were prepared by using the precipitation method. They were characterised by modern techniques for instance; BET, XRD, SEM, UV/Vis, FTIR, PL, CV, and EIS instruments. In case of Cu2O/CeO2 composite, it has band gap energy of 2.01 eV and specific surface area of about 32.01 m2g−1. The degradation efficiency was analysed by comparing the decolourization of methyl orange dye solution and wastewater sample collected from Mojo Tannery Factory at 140 irradiation times. In comparisons with other counterparts Cu2O/CeO2 (1:1) exhibited high efficiency for both methyl orange (95.03%) and wastewater (56.67%) solutions. This is due to the indication of a high-quality heterojunction between CeO2 and Cu2O that stimulates the transfer of charge carriers and partition of photogenerated electron-hole pairs. The effects of scavengers confirmed that hole (h+) and superoxide anion (•O2-) trapping species play a crucial role, while hydroxyl radical (•OH-) scavengers are not a principal factor. The stability tests have shown that the nanocomposite was reasonably excellent after five cycles, with a decolorization ability of 68.55% of MO solution. Furthermore, the outcome indicates that Cu2O/Ce2O nanomaterials may be used to cure industrial pollution by eliminating toxic materials.

The Study on the Novel Complex Structure and Photocatalytic Degradation Ability of Manganese

The vigorous development of the dye industry has led to increasingly serious harm to the water environment. Currently, dye wastewater has become one of the most difficult industrial wastewater to degrade. Therefore, how to treat dye wastewater in a green and economical manner is receiving increasing attention. Photocatalytic technology has attracted much attention in the treatment of dye wastewater due to its advantages such as fast speed, no selectivity, and complete degradation. However, the current application of traditional photocatalytic materials is greatly limited due to the high recombination rate of photo generated charge carriers and the difficulty in separating and recovering powder catalysts. Therefore, it is of great significance to study the preparation and application of visible light response catalysts with high catalytic activity. The structure of the complex was characterized by X-ray single crystal diffractometer, and the manganese complex was determined by UV and IR spectroscopy, which was then used for the photocatalytic degradation of methyl orange solution.