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In this study, zinc oxide-activated carbon nanocomposite was used as the adsorbent for the remediation of dieldrin in aqueous media. Zinc oxide nanoparticles (ZNPs) were synthesized from Cissus quadrangularis (C. quadrangularis) leaf extract, and activated carbon was derived from maize cobs. Nanocomposites were formulated by mixing the ZNPs with th...
Citations
... N-TiO 2 -PVDF uniquely indicated a peak at a region close to 1743 cm − 1 . This indicated the presence of carboxylic groups [54]. This vibration was caused by glutaraldehyde used in the cross-linking [29]. ...
The increasing presence of microbial and emerging organic contaminants pose detrimental effects on the environment and ecosystem such as diseases, pandemics and toxicity. Most of these synthetic pollutants are biorecalcitrant and therefore persist in the environment. Conventional water treatment methods are not effective thereby necessitating the development of advanced techniques such as photocatalysis and membrane processes. In this study, visible light-driven photocatalytic membrane was synthesized through the immobilization of nitrogen-doped nanoparticles onto the polyvinylidene fluoride (PVDF) membrane and performance evaluated with E.coli microbial contaminant removal. Characterization was done using Fourier transform infrared spectra, X-ray diffraction (XRD), water contact angle, Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX). The Nitrogen-doping of titanium dioxide red-shifted the light absorption to a visible range of 440 nm from 400 nm. Nitrogen dopant was detected at 1420 cm⁻¹and 1170 cm⁻¹ for nitrogen doped nanoparticles and 1346-1417 cm⁻¹ for nitrogen doped titanium dioxide PVDF membrane. SEM-EDX confirmed presences of nitrogen in nitrogen doped titanium dioxide nanoparticles on membrane surface with nitrogen elemental composition of 0.01 % wt. The water contact angle reduced by 81.39o from 120.14o to 38.75o because of PVA immobilization of nitrogen-doped titanium dioxide and glutaraldehyde crosslinking. Nitrogen doping resulted in visible light active photocatalytic membranes with better hydrophilicity and fouling resistance. 8.42 E.coli log removal and a relative flux of 0.35 was obtained within 75 min. The developed photocatalytic membrane enables the use of sunlight hence a less costly method for decontamination of wastewater.
... Upon examination of the spectra, it became abundantly evident that the ZnO nanobars nanocomposites displayed a pattern that was indicative of hexagonal nanobars. The agglomeration that was seen in the composite that was manufactured is an investigation into the successful inclusion of ZnO nanotubes and AC, respectively [30]. In addition to this, it was discovered that most of the particles are nanobars that are hexagonal in shape, where dark particles of ZnO NBs were anchored with the surface of the AC. ...
In this present work, synthesize Zinc Oxide Nanobars (ZnO NBs) and Activated carbon (ZnO NBs/AC) nanocomposites using a simple sol–gel technique. The prepared samples were studied with various characterization techniques to determine the structure’s structural, optical, and electrical properties, including X-ray diffraction, UV-visible, HR-SEM, FTIR, and cyclic voltammetry. The XRD results revealed that the intensities of all crystal planes in bare ZnO NBs are higher than in ZnO NBs/AC composites. The average crystallite size of ZnO NBs and their composite was 10 and 30 nm, respectively. The band gap of the ZnO NBs and ZnO NBs/AC nanocomposite was calculated to be 3.3 eV and 2.8 eV. HR-SEM analysis shows the ZnO NBs are hexagonal, whereas the ZnO NBs/AC composite contains hexagonal ZnO NBs incorporated in AC. The FTIR analysis found the functional groups of ZnONBs and ZnO NBs/AC nanocomposites. The specific capacitance of ZnO NBs/AC was found to be six times higher than that of pure ZnO NBs, as revealed by cyclic voltammetry-based electrochemical analysis.
Graphical Abstract
... A Scanning Electron Microscope (SEM, JSM-7600F, Japan) was used to study the surface morphology of biochar (Details on SEM analysis have already been reported by [43]). The 8 samples for SEM analysis were the same as for FT-IR analysis above: NA-WB500-BA, NA-W-B500-AA, A-WB500-BA, A-WB500-AA, NA-MB350-BA, NA-MB350-AA, A-MB350-BA and A-MB350-AA. ...
... Characterization of the prepared ZnO-CR NPs was conducted using a comprehensive suite of analytical techniques. X-ray diffraction (XRD) was utilized to assess crystallinity, scanning electron microscopy (SEM) was employed to analyze size and morphology, and Fourier-transform infrared spectroscopy (FTIR) was utilized to examine surface functional groups [23][24][25]. ...
Background
Kappaphycus alvarezii, a marine red algae species, has gained significant attention in recent years due to its versatile bioactive compounds. Among these, κ-carrageenan (CR), a sulfated polysaccharide, exhibits remarkable antimicrobial properties. This study emphasizes the synergism attained by functionalizing zinc oxide nanoparticles (ZnO NPs) with CR, thereby enhancing its antimicrobial efficacy and target specificity against dental pathogens.
Methods
In this study, we synthesized ZnO-CR NPs and characterized them using SEM, FTIR, and XRD techniques to authenticate their composition and structural attributes. Moreover, our investigation revealed that ZnO-CR NPs possess better free radical scavenging capabilities, as evidenced by their effective activity in the DPPH and ABTS assay.
Results
The antimicrobial properties of ZnO-CR NPs were systematically assessed using a zone of inhibition assay against dental pathogens of S. aureus, S. mutans, E. faecalis, and C. albicans, demonstrating their substantial inhibitory effects at a minimal concentration of 50 μg/mL. We elucidated the interaction between CR and the receptors of dental pathogens to further understand their mechanism of action. The ZnO-CR NPs demonstrated a dose-dependent anticancer effect at concentrations of 5 μg/mL, 25 μg/mL, 50 μg/mL, and 100 μg/mL on KB cells, a type of Human Oral Epidermal Carcinoma. The mechanism by which ZnO-CA NPs induced apoptosis in KB cells was determined by observing an increase in the expression of the BCL-2, BAX, and P53 genes.
Conclusion
Our findings unveil the promising potential of ZnO-CR NPs as a candidate with significant utility in dental applications. The demonstrated biocompatibility, potent antioxidant and antiapoptotic activity, along with impressive antimicrobial efficacy position these NPs as a valuable resource in the ongoing fight against dental pathogens and oral cancer.
... The majority of the functional group may have been pyrolyzed as a result of treatment at high temperature. The bands centered at 1463 cm -1 are assigned to C=C bonds in activated carbon [38]. For the AC/ZnO samples, the bands in the range 3100-3450 cm -1 can be observed, suggesting the presence of the O-H groups. ...
Due to the rapid growth of various industrial activities, huge quantities of harmful water contamination are continuously discharged into the water sources causing a series of environmental hazards and problems. Among the most hazardous pollutants of aquatic environment is wastewater containing colored substances that resist biodegradation. Therefore, sufficient and cost-effective techniques is necessary to reduce the pollution risks of the aquatic environment. In the present work, activated carbon (AC) samples were synthesized from Pontederia crassipes leaves and then incorporated with zinc oxide nanoparticles (ZnO NPs) for removing Congo red (CR) dye from aqueous solutions. The morphology, phase structure, surface texture, chemical composition, and optical properties of synthesized nanomaterials were investigated using XRD, FTIR, EDS, FESEM, TEM, RAMAN, and DRS. The results exhibited that inclusion of different AC ratios into ZnO nanostructure had significant effects on structural, morphological, optical, and photodegradation properties. The ZnO/AC(15%) nanocomposite showed the highest photocatalytic performance in terms of photodegradation efficiency as PDE% = 99.17 under optimum conditions ([CR] = 100 ppm, pH = 3, catalyst dose = 1.4 g/L and irradiation time = 180 min). The kinetics study showed that the dye’s photocatalytic degradation reaction was fitted to a pseudo-first-order reaction. The reusability study showed that the ZnO/AC (15%) photocatalyst exhibited a promising photostability, where it retained 82% of its initial photocatalytic activity after successive five cycles. The scavenging study showed that the major active species are responsible for photocatalytic degradation of CR dye are h⁺ and ˙OH. The most significant reduction of photocatalytic activity was caused by the addition of non-ionic surfactants. Results showed that the treatment of CR solution by ZnO/AC (15%)-H2O2 system increased PDE% more than 44% after 60-min irradiation.
Due to their long-term environmental persistence and propensity to cause serious health issues, “dirty dozen” chemicals (DDCs) are a big concern when found in marine environments. With the urgent need to remove them from water, this work presents an extensive evaluation of the adsorption technique for removing DDCs from aqueous environments. From review, the physicochemical characteristics of the adsorbent, the pH of the solution, and the DDCs property are the key factors that affect adsorption chemistry. The highest reported adsorption capacity for DDCs is 967 mg/g for H3PO4 activated carbon derived from wood observed in the removal of 2-monochlorinated biphenyl. The key mechanisms for DDCs uptake was observed to be complexation, π-π interactions, hydrophobic contacts, electrostatic interactions, hydrogen bonding, and pore filling. Most DDCs uptake is favoured in the neutral pH range which is ideal for potential scaled-up operations as acidification can have significant cost implications. DDCs are efficiently eluted from spent adsorbents using organic solvents (ethanol, methanol and hexane) and most adsorbents are reusable for 3–10 cycles. Future studies can focus on developing a better understanding of the cost performance of adsorption for DDCs removal, an area not fully explored currently. It is surmised that adsorption is ideal for DDCs removal and avenues for scalable application of the technology to be explored.
BACKGROUND
Conventional treatment processes and existing photocatalysts have proven insufficient in efficiently removing aldrin and dieldrin. Consequently, this study aimed to investigate the removal of aldrin and dieldrin from surface water using a titanium dioxide/graphene oxide/copper ferrite (TiO₂/GO/CuFe₂O₄) nanocomposite.
RESULTS
The highest photodegradation efficiencies for aldrin (100%) and dieldrin (99%) were achieved with a TiO₂/GO/CuFe₂O₄ nanocomposite dosage of 1.3 mg L⁻¹, at a sunlight intensity of 9 W m⁻² and an optimal photodegradation time of 25 min. The maximum UV absorption wavelength of the TiO₂/GO/CuFe₂O₄ nanocomposite was observed at 365 nm. The quantum yield of the nanocomposite was recorded as 2.69 × 10² mol einstein⁻¹, and its bandgap energy was determined to be 3.31 eV. The first‐order kinetic rate constants for aldrin and dieldrin were calculated as 0.05 and 0.047 min⁻¹, respectively. X‐ray diffraction analysis confirmed the crystal structure of CuFe₂O₄/TiO₂, while Fourier transform infrared spectroscopy detected carboxylic, epoxy, carbonyl and other oxygenated groups within the TiO₂/GO/CuFe₂O₄ nanocomposite. Scanning electron microscopy and transmission electron microscopy images revealed that CuFe₂O₄ was situated on the outer layer of GO. Energy‐dispersive X‐ray analysis identified the elemental composition of the TiO₂/GO/CuFe₂O₄ nanocomposite as comprising GO, C, Cu, Fe, Ti and O. A reusability study demonstrated that the nanocomposite maintained excellent performance, achieving 99% removal efficiency after 79 cycles and 97% after 100 cycles.
CONCLUSIONS
The TiO₂/GO/CuFe₂O₄ nanocomposite effectively removed aldrin and dieldrin from surface water. This nanocomposite holds promise for the remediation of other aquatic ecosystems, such as bays, rivers and ocean waters. © 2024 The Author(s). Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).
The fruit extract of Buchanania Obovata and the eutectic-based ionic liquid were utilized, in an eco-friendly, inexpensive, simple method, for synthesizing zinc oxide nanoparticles (ZnO NPs). The influence of the reducing, capping and stabilizing agents, in both mediums, on the structure, optical, and morphological properties of ZnO NPs was extensively investigated. The surface plasmon resonance peaks were observed at 340 nm and 320 nm for the fruit-based and the eutectic-based ionic liquid mediums, respectively, indicating the formation of ZnO NPs. XRD results confirmed the wurtzite structure of the ZnO NPs, exhibiting hexagonal phases in the diffraction patterns. The SEM and TEM images display that the biosynthesized ZnO NPs exhibit crystalline and hexagonal shape, with an average size of 40 nm for the fruit-based and 25 nm for the eutectic-based ionic liquid. The BET surface area analysis, revealed a value ~13 m2 g−1 for ZnO NPs synthesized using the fruit extract and ~29 m2 g−1 for those synthesized using the eutectic-based ionic liquid. The antibacterial activity of the biosynthesized ZnO NPs was assessed against clinically isolated Gram-negative (E. coli) and Gram-positive (S. aureus) bacterial strains using the inhibition zone method. The ZnO NPs produced from the eutectic-based ionic liquids confirmed superior antibacterial activity against both S. aureus and E. coli compared to those mediated by the utilized fruit extract. At a concentration of 1000, the eutectic-based ionic liquid mediated ZnO NPs displayed a maximum inhibition zone of 16 mm against S. aureus, while against E. coli, a maximum inhibition zone of 15 mm was observed using the fruit extract mediated ZnO NPs. The results of this study showed that the biosynthesized ZnO NPs can be utilized as an efficient substitute to the frequently used chemical drugs and covering drug resistance matters resulted from continual usage of chemical drugs by users.
