Zinc Oxide Composites Research Articles

Enhanced degradation of crystal violet using PANI-ZnO nanocomposites: Electro-oxidation and photocatalysis studies

This work compares the transformation capabilities of crystal violet (CV), a toxic cationic dye of the triphenylmethane family, by advanced oxidation processes, especially heterogeneous photocatalysis and electrochemical oxidation, on new nanocomposite materials with a composition of zinc oxide (ZnO) and polyaniline (PANI) by chemical polymerization in solution. Concerning the synthesis of PANI, we have exploited the radical oxidative polymerization method; this latter is functional and uncomplex, as it does not require expensive equipment, using ammonium persulfate as an oxidant with a part of monomer (Aniline) to remove pollutants present in the environment. After physicochemical analyses including FTIR, SEM, and electrochemical characterizations by cyclic voltammetry and conductimetry, the results show that the photocatalytic activity of PANI-ZnO 5 % resulted in a better yield (85 %) compared to PANI alone and other composites (PANI-ZnO 10 % and PANI-ZnO 20 %). However, the electro-oxidation discoloration rates on all PANI alone and PANI-ZnO composite electrodes (5 %, 10 %, and 20 %) reached almost 99 %. To deepen our understanding, computational DFT calculations were employed, complementing experimental findings, and together, they contribute to elucidating the intricate mechanisms underlying the enhanced performance of these nanocomposite materials in both photocatalysis and electrochemical oxidation processes.

Synthesis, characterization, and humidity sensing performance of polyaniline bismuth-doped zinc oxide (PANI-Bi-ZnO) composites

Synthesis, characterization, and humidity sensing performance of polyaniline bismuth-doped zinc oxide (PANI-Bi-ZnO) composites

Efficient and stable supercapacitors using rGO/ZnO nanocomposites via wet chemical reaction

The electrochemical behaviorof metal oxide nanoparticles (NPs) can be improved by maximizing the surface area and combining materials with high electrical conductivity. The reduced graphene oxide (rGO) enables to bestow a larger surface area for intercalation and deintercalation as well as shorter paths for ion transfer, lowering ionic resistance. In the current research, hybrid composites of rGO and zinc oxide (ZnO) NPs were successfully synthesized by using a wet chemical method for the application of supercapacitors. The wet chemical technique for industrial-scale nanocomposite synthesis is easy, fast, and cost-effective and requires no specialized equipment. The size, surface morphology, and crystalline structure of the rGO/ZnO nanocomposites were characterized by using FE-SEM, HR-TEM, and XRD, respectively. By using cyclic voltammetry and Galvanostatic charge–discharge tests, it was confirmed that the capacitances of rGO/ZnO composites were significantly enhanced compared to that of pure ZnO NPs. The proposed nanocomposite could achieve significantly enhanced specific capacitance (258 Fg−1) and also, it was able to achieve a longer life cycle with maximum capacitance retention. We expect that this work provides a simple but very effective strategy for the rGO and metal oxide NP composites.

Synthesis, Characterization, and Antimicrobial Evaluation of Poly(benzaldehyde-co-thiophene)/Zinc Oxide (PBT/ZnO) Composites for Potential Applications

Synthesis, Characterization, and Antimicrobial Evaluation of Poly(benzaldehyde-co-thiophene)/Zinc Oxide (PBT/ZnO) Composites for Potential Applications

Valorization of agroindustrial orange peel waste during the optimization of activated carbon–multiwalled carbon nanotubes–zinc oxide composites used in the removal of methylene blue in wastewater

Activated carbons (AC) produced from agroindustrial orange peel (OP) wastes and/or commercial multi–walled carbon nanotubes (MWCNTs) were modified with ZnO nanoparticles in different amounts (15 and 30 wt–%) for the removal of methylene blue in aqueous solutions. The MWCNTs functionalization was carried out by typical procedure in acid medium using a ratio of 3:1 (HNO3/H2SO4). A batch adsorption analysis was carried out evaluating different parameters: MB concentration from 40 to 100 mg L–1; pH values between 4 and 10 and adsorption time that varied from 1 to 48 h. The modified materials were characterized through the techniques XRD, FTIR, BET, TGA, SEM and UV–vis. The results showed an adequate dispersion of ZnO NPs on the carbon surfaces with a typical flower–like morphology this type of shape developed micropores that facilitate adsorption phenomena. Under the evaluation conditions, 20 mg of carbon–based materials can remove up to 89.5 ± 4.47 % of MB (80 ppm) after 24 h of exposure at a regulated pH of 8. The equilibrium adsorption data were better fitted by a Langmuir isotherm (R2 = 0.9999) than the Freundlich model (R2 = 0.9366); showing in the best case a maximum adsorption capacity of 1250 mg g−1 for both materials with 30 wt–% of ZnO NPs (AC–MWCTs or MWCNTs). Experimental data also suggest that the most likely mechanism is chemisorption followed by physical adsorption. Then, the compounds with 30 wt–% metal loading (ZnO NPs), AC–MWCNTs–ZnO or MWCNTs–ZnO, displayed the most interesting properties for MB dye removal. AC–ZnO compounds can also remove about 88.75 ± 4.43 % of MB, demonstrating that it can also be a facile and low–cost method to improve the surface area in carbonaceous structures by promoting a strong interaction with the ZnO NPs, which in turn helps to remove contaminants in water efficiently.

Synthesis and characterization of fluorescent and thermochromic bifunctional composites: Polydiacetylene/zinc oxide quantum dots

Composites of polydiacetylenes (PDA) and zinc oxide (ZnO) find diverse applications in thermochromic inks, colorimetric sensors, and anticounterfeiting, albeit often with complex preparation methods, single functionality, and high color-changing temperature ranges. This study presents environmentally friendly aqueous composites exhibiting dual thermochromic and fluorescent properties, achieved by integrating ZnO quantum dots (QDs) with particle sizes below 10 nm with PDA. By varying the concentration ratio of ZnO QDs to PDA, the effects on fluorescence and thermochromic properties were systematically explored. The interaction between ZnO QDs and PDA interfaces causes alterations to the energy states in the conjugated π-orbital array within PDA molecules. In contrast to pure PDA solutions, the composite materials not only exhibit thermochromism but also fluorescence. Demonstratively, the composite was applied as functional ink or paste for writing, film production, and inkjet printing, maintaining robust thermochromic sensitivity and fluorescence properties in the resulting specimens. This methodology imparts excellent multifunctionality to composite materials, enhancing and broadening their application potential.

Thermomechanical evaluation of zinc oxide/hydroxyapatite/high‐density polyethylene hybrid composites

AbstractThis study examines the impact of zinc oxide (ZnO) on the spectral, thermal, mechanical, and morphological characteristics of developed composites of high‐density polyethylene (HDPE). Composite samples were fabricated with different compositions of ZnO (0, 5, 10, 15, and 20 wt%) along with a constant quantity of hydroxyapatite (HA, 10 wt%) in pure HDPE. The synthesized hybrid polymer composites were characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), universal testing machine (UTM), and field emission scanning electron microscopy (FESEM) methods, allowing for a thorough assessment of their spectral, thermal, mechanical, and morphological properties, repectively. FTIR analysis revealed the presence of HA and ZnO metal vibrations in the hybrid polymer samples. The thermal stability was increased by the incorporation of different amounts of ZnO, and the decomposition temperature was increased from 319.31 to 412°C for 10 wt% of ZnO hybrid composites as compared to pure HDPE. DSC findings indicated that increasing the ZnO contents, prompted the degree of crystallinity to rise to 14.81% as contrasted to neat HDPE. It was observed that yield strength and ultimate tensile strength for the 10 wt% ZnO composite increased up to 51.85% and 31.72%, respectively, compared to pure HDPE. However, at higher loading of ZnO, surface cracks were observed, which is detrimental for composite materials. Hence, the improved attributes indicated that the synthesized ZnO/HA/HDPE polymer composites can be a promising material for biomedical engineering applications.

Synthesis and characterization of highly sensitive ammonia sensor based on polyaniline/bismuth doped zinc oxide composites

AbstractHighly efficient gas sensors fabrication having low detection limits have been one of key research area due to the industrial, environmental and other technological applications. In this study, polyaniline/bismuth doped zinc oxide (PANI/Bi‐ZnO) was prepared via inverse emulsion polymerization and it was coated over a substrate with staggered electrodes to create a highly efficient ammonia (NH3) sensor. The UV/Vis investigation, fourier transformed infrared (FTIR), raman spectral analysis, and scanning electron microscopy (SEM) were used to describe the structure and morphology of prepared samples. At room temperature, the PANI/Bi‐ZnO sensor's sensitivity to various NH3 gas concentrations ranging from 20 to 100 ppm was examined. According to the experimental findings, the PANI/Bi‐ZnO film exhibits outstanding performance of response and selectivity. The response at 20 ppm NH3 was as high as ⁓100%. The response and recovery time was also calculated at 20 ppm and was 11/15 s. The contact between p‐n heterojunctions in the composite is responsible for the exceptional sensitivity of PANI/Bi‐ZnO towards NH3 sensing.Highlights Synthesis of Bi doped ZnO composites with PANI at room temperature Fabrication of highly sensitive and efficient resistive type ammonia sensor Selective and robust detection of ammonia by the fabricated sensor High sensitivity with low limit of detection offered by the sensor Response of the fabricated sensor at 20 ppm NH3 was as high as ⁓100%

Merging polymers of intrinsic microporosity and porous carbon-based zinc oxide composites in novel mixed matrix membranes for efficient gas separation

Mixed matrix membranes (MMMs) have demonstrated significant promise in energy-intensive gas separations by amalgamating the unique properties of fillers with the facile processability of polymers. However, achieving a simultaneous enhancement of permeability and selectivity remains a formidable challenge, due to the difficulty of achieving an optimal match between polymers and fillers. In this study, we incorporate a porous carbon-based zinc oxide composite (C@ZnO) into high-permeability polymers of intrinsic microporosity (PIMs) to fabricate MMMs. The dipole–dipole interaction between C@ZnO and PIMs ensures their exceptional compatibility, mitigating the formation of non-selective voids in the resulting MMMs. Concurrently, C@ZnO with abundant interconnected pores can provide additional low-resistance pathways for gas transport in MMMs. As a result, the CO2 permeability of the optimized C@ZnO/PIM-1 MMMs is elevated to 13,215 barrer, while the CO2/N2 and CO2/CH4 selectivity reached 21.5 and 14.4, respectively, substantially surpassing the 2008 Robeson upper bound. Additionally, molecular simulation results further corroborate that the augmented membrane gas selectivity is attributed to the superior CO2 affinity of C@ZnO. In summary, we believe that this work not only expands the application of MMMs for gas separation but also heralds a paradigm shift in the application of porous carbon materials.

Modified Ag-ZnO coated graphene oxide ternary composite for superior photocatalytic degradation of crystal violet dye under visible light irradiation

The enhancement of advanced nanomaterials into photocatalytic applications has preserved a significant curiosity for its potential to address environmental challenges. To address this concern, a green and eco-friendly catalyst was fabricated. In this study, we examined the enhancement of the photocatalytic activity of various synthesized composites with the modification of graphene oxide (GO) and Ag over the surface of semiconductor zinc oxide (ZnO). The simple wet chemical method was used for the synthesis of ZnO, GO(x)@ZnO, Ag2@ZnO and GO(x)Ag2-ZnO composites [x = 1,3,5 wt%]. The synthesized samples were characterized by different techniques such as XRD, SEM-EDS, DRS, Raman, and PL. Ternary GO5@Ag2-ZnO photocatalyst exhibited superior degradation efficiency up to 97 % in degrading crystal violet (CV) dye, a persistent and environmentally concerning pollutant under visible light irradiation. The significant photocatalytic activity was attributed to the surface plasmon resonance (SPR) phenomenon of Ag, whose broad absorption band was observed in DRS, better electron mobility, and a large surface area of GO facilitates the charge transfer. The highly efficient catalyst was effectively employed for five repeating cycles with only an 11 % decrease in removal rate, demonstrating that it can be easily reused. Kinetic study reveals that the prepared composite follows a pseudo-first-order reaction model with the highest rate constant value of 0.02491 min−1 respectively. The possible degradation pathway was determined using the HRMS technique.

Cobalt ferrite induced enhancement in the thermoelectric properties of zinc oxide composites

Thermoelectric (TE) material devices can be treated as an initiative to reduce global warming by scavenging waste heat and recycling it into useful electrical energy. In dual-phase materials, the energy filtering mechanism serves a significant role to enhance power factor by controlled electrical conductivity and Seebeck coefficient in connection with carrier concentration and carrier mobility. Here we performed the preparation of Cobalt Ferrite (CF) using mechanical alloying and the cf@zno composites via solid state reaction technique by varying stoichiometric weight between CF and ZnO. The magnetic, electric, and optical properties of the samples exposed the influence of CF on the TE properties of ZnO matrix. The cf7.5wt%@zno sample shows greater carrier mobility and moderate carrier concentration results the improved electrical conductivity value 4235 Sm−1 and hence achieved highest power factor 439 μWm−1K−2.

Formation of zinc oxide composites of doxycycline with high antibacterial activity based on DC-magnetron deposition of ZnO nanoscale particles on the drug surface

Formation of zinc oxide composites of doxycycline with high antibacterial activity based on DC-magnetron deposition of ZnO nanoscale particles on the drug surface

Efficient CO2 adsorption using chitosan, graphene oxide, and zinc oxide composite

This study was deeply focused on developing a novel CTS/GO/ZnO composite as an efficient adsorbent for CO2 adsorption process. To do so, design of experiment (DOE) was done based on RSM-BBD technique and according to the DOE runs, various CTS/GO/ZnO samples were synthesized with different GO loading (in the range of 0 wt% to 20 wt%) and different ZnO nanoparticle’s loading (in the range of 0 wt% to 20 wt%). A volumetric adsorption setup was used to investigate the effect of temperature (in the range of 25–65 °C) and pressure (in the range of 1–9 bar) on the obtained samples CO2 uptake capability. A quadratic model was developed based on the RSM-BBD method to predict the CO2 adsorption capacity of the composite sample within design space. In addition, CO2 adsorption process optimization was conducted and the optimum values of the GO, ZnO, temperature, and pressure were obtained around 23.8 wt%, 18.2 wt%, 30.1 °C, and 8.6 bar, respectively, with the highest CO2 uptake capacity of 470.43 mg/g. Moreover, isotherm and kinetic modeling of the CO2 uptake process were conducted and the Freundlich model (R2 = 0.99) and fractional order model (R2 = 0.99) were obtained as the most appropriate isotherm and kinetic models, respectively. Also, thermodynamic analysis of the adsorption was done and the ∆H°, ∆S°, and ∆G° values were obtained around − 19.121 kJ/mol, − 0.032 kJ/mol K, and − 9.608 kJ/mol, respectively, indicating exothermic, spontaneously, and physically adsorption of the CO2 molecules on the CTS/GO/ZnO composite’s surface. Finally, a renewability study was conducted and a minor loss in the CO2 adsorption efficiency of about 4.35% was obtained after ten cycles, demonstrating the resulting adsorbent has good performance and robustness for industrial CO2 capture purposes.

Role of Structural Decisive via Ultra‐Sonication on Photocatalytic Response of MWCNTs Intercalated ZnO Composites

AbstractIn this manuscript role of MWCNTs on the photocatalytic response of zinc oxide (ZnO) semiconductor photocatalyst is reported. Developing a cheap, stable, and effective photo catalyst is necessary for remediation of persistent organic pollutants. To address this challenge, ZnO/MWCNT composites are fabricated via sonication technique with interfacial engineering for effective photocatalytic response. X‐ray diffraction spectra confirms hexagonal structure of ZnO/MWCNT composites with the average particle size distribution of 73–80 nm. FT‐IR spectra confirms bonding structure, however SEM images confirm the homogeneous distribution of MWCNTs in the ZnO system which acts as an effective adsorbent sites. The highest degradation (90%) of methylene blue (MB) dye on ZnO95MWCNT5 composite has been observed. It is expected that MWCNTs taking part to electron transfer facilitation in spatial separation and electron–hole pairs of ZnO during photo catalysis mechanism.

Fabrication and Characterization of Eco-Friendly Polystyrene Based Zinc Oxide-Graphite (PS/ZnO-G)

One of the most significant environmental challenges nowadays is the rising manufacturing of non-biodegradable polymer wastes like polystyrene. In order purpose of manufacture environmentally friendly polystyrene that easily decomposes, a solvent approach was used to create polystyrene based zinc oxide- graphite composites. The surface morphology and materials contained in the modified polystyrene were evaluated by scanning electron microscopy-energy dispersive X-ray analysis to verify the dispersion and distribution of the nanoparticles by scanning electron microscopy and the material contents by energy dispersive X-ray analysis. While the crystal structure, chemical bonds, and functions were determined by X-ray Diffraction and Fourier transform infrared, no change in the chemical structure occurred in polystyrene. Thermogravimetric analysis was used to assess the thermal decomposition. And its results found that the temperature of the decomposition was 46.78° lower in zinc oxide and graphite-based polystyrene composites than in pure polystyrene. It came to light that the presence of zinc oxide nanoparticles causes phase separation and consequently impacts the thermal behaviour of graphite-based polystyrene composites. The phase separation was demonstrated by the Thermogravimetric curves showing two degrading steps. This satisfies the urgent demand to synthesize polystyrene that is eco-friendly and easy to thermally decomposition, as well as easy to recycle, which benefits both the environment and the commercial side.

Synergistic effect of polymer blend compositions on the structural, thermal, optical, and broadband dielectric properties of P(VDF-HFP)/PEO/ZnO polymer nanocomposites

Polymer nanocomposites (PNCs) composed of poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP))/ poly(ethylene oxide) (PEO) blend host matrix of varying compositions i.e., xP(VDF-HFP)/(100–x)PEO with x values 20, 50, and 80 wt%, and zinc oxide (ZnO) as nanofiller (2 wt%) are prepared by state-of-the-art homogenized solution cast method. The SEM micro-images of these PNC films revealed that the polymer blend compositions considerably affect the polymers miscibility, spherulitic morphologies, and crystalline phases. FTIR spectra demonstrated that the P(VDF-HFP) and PEO chain interactions in these PNCs change significantly with the polymer blend compositions. The DSC results revealed a decrease in PEO crystallite temperature and degree of crystallinity with the increase of P(VDF-HFP) amount in the blend matrix of these PNC materials. Analysis of UV-Vis spectra categorized these PNCs of wide band gap (∼ 3.1 eV) semiconductive optical materials. Broadband frequency range (20 Hz–1 GHz) dielectric dispersion demonstrated that 50P(VDF-HFP)/50PEO-2 wt% ZnO composition based nanodielectric film has a relatively high dielectric constant, whereas the chain segmental and dipolar reorientation relaxation processes are strongly polymer blend composition dependent for these PNC materials. The experimental results are discussed in detail concerning the multifunctionality of these PNCs as promising candidates for innovation in flexible optoelectronic and nanodielectric-based microelectronic devices.

Synthesis and characterisation of carbon nanotubes and zinc oxide composites: sub-millisecond UV response

Synthesis and characterisation of carbon nanotubes and zinc oxide composites: sub-millisecond UV response

Insight assessment of the morphological and photocatalytic properties of ZnO-anchored graphitic carbon nitride interlayer composite for emerging antibiotic removals in water under visible light

In this study, the effect of different zinc oxide (ZnO) compositions anchored on graphitic carbon nitride (CN) was investigated through characterization and the photocatalytic degradation performance on the antibiotics tetracycline, ciprofloxacin, cephalexin, and erythromycin A. The ZnO was prepared through the phyto-synthesis route using Garcinia mangostana pericarp extract; whilst the CN was fabricated using melamine, an organic and cheap carbon nitride source. For the ZnO-anchored CN (ZnO@CN), the composition of 15% of ZnO exhibited an adequate balance of each component effect and was determined to be superior in properties. The high-resolution transmission electron microscopy images revealed the intercalation of the nanoparticles between the sheets, greatly infusing the photocatalytic and electrochemical properties. The bandgap modification of the material showed that the overall bandgap was reduced to 2.42 eV, suitable for operating in the visible region and creating multiple free radicals. For the photocatalytic deterioration of tetracycline, the optimal conditions of 15 mg of the superior material, 50 mL of the 10-ppm concentration, and 120 min of irradiation were affirmed, which removed over 95% of the antibiotic. Further investigation into other types of antibiotics reveals the efficiency was all higher than 50%. Through the mechanism proposal, the degradation pathways were elucidated regarding the molecular structure of the antibiotic.

Preparation of nano zinc oxide composite porous membrane and its material regulation

This paper introduces various preparation methods for nanoporous membranes composed of zinc oxide composites and addresses the low light transmittance issue commonly associated with existing methods. A nanoporous composite membrane, which utilizes PEG as an auxiliary agent, has been designed to optimize light transmittance. The experimental results indicate that the specific surface area of the nano zinc oxide composite porous membrane is [51.8 m2/g, 74.65 m2/g]. Within the interval, the pore volume is greater than 0.33 cm³/g. Within the range of [50 Å, 60 Å], the gas adsorption and separation performance are relatively higher. The nano zinc oxide composite porous film prepared with PEG has a transmittance of approximately 90%, demonstrating excellent transmission performance. These findings suggest that the designed composite membrane has strong performance characteristics, offering significant potential for further development and application in this field. It also offers useful reference and guidance for material preparation and optimization.

Nano-impregnation on metakaolin backbone for enhanced removal of Cu(II) and Mn(II) ions in a binary system using fixed bed column

This paper presents a comprehensive study on the synthesis and characterization of a novel composite material composed of metakaolin (MK), cellulose nanofibers (CNF), graphene oxide (GO), and zinc oxide (ZnO) for the efficient removal of heavy metals from wastewater. The main objective of this research was to enhance the removal efficiency of Cu(II) and Mn(II) ions in a binary system using a fixed bed column adsorption technique while investigating the effect of impregnating the nanomaterials. The synthesized samples were subjected to a thorough characterization using various techniques. These analyses provided insights into the structural properties and morphology of the composite material. The adsorption performance of the MK/CNF/GO/ZnO composite was evaluated through breakthrough curve analysis and kinetic modeling. The MDR model provided good fits with R2 values of 0.962 and 0.967 for Cu(II) and Mn(II) respectively. Based on the experimental breakthrough curve data, the saturation and breakthrough capacities of the composite material were calculated to be 5.97 mg/g and 4.84 mg/g for Cu(II) and Mn(II) respectively, achieved after a saturation time of 102 min for Cu(II) and 128 min for Mn(II). The results demonstrated a synergistic effect between GO and CNF, resulting in enhanced adsorption efficiency. The incorporation of ZnO nanoparticles further improved the adsorption capacity due to their high surface area, providing additional active sites for adsorption. The results showed that combining CNF, GO, and ZnO in a composite resulted in extended breakthrough and exhaustion times compared to the combination of CNF and GO alone.