Displaying publications 1 - 20 of 225 in total

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  1. Rafiqul ISM, Mimi Sakinah AM, Zularisam AW
    Prep Biochem Biotechnol, 2021;51(10):1060-1070.
    PMID: 33724897 DOI: 10.1080/10826068.2021.1897840
    Enzymatic production of bioxylitol from lignocellulosic biomass (LCB) provides a promising alternative to both chemical and fermentative routes. This study aimed to assess the impacts of catalytic variables on bioxylitol production from wood sawdust using xylose reductase (XR) enzyme and to optimize the bioprocess. Enzyme-based xylitol production was carried out in batch cultivation under various experimental conditions to obtain maximum xylitol yield and productivity. The response surface methodology (RSM) was followed to fine-tune the most significant variables such as reaction time, temperature, and pH, which influence the synthesis of bioxylitol from sawdust hydrolysate and to optimize them. The optimum time, temperature, and pH became were 12.25 h, 35 °C, and 6.5, respectively, with initial xylose 18.8 g/L, NADPH 2.83 g/L, XR 0.027 U/mg, and agitation 100 rpm. The maximum xylitol production was attained at 16.28 g/L with a yield and productivity of 86.6% (w/w) and 1.33 g/L·h, respectively. Optimization of catalytic parameters using sequential strategies resulted in 1.55-fold improvement in overall xylitol production. This study explores a novel strategy for using sawdust hemicellulose in bioxylitol production by enzyme technology.
    Matched MeSH terms: Zinc Oxide/metabolism*
  2. Zhou H, Wu L, Wang HQ, Zheng JC, Zhang L, Kisslinger K, et al.
    Nat Commun, 2017 11 14;8(1):1474.
    PMID: 29133800 DOI: 10.1038/s41467-017-01655-5
    Multi-layer structure of functional materials often involves the integration of different crystalline phases. The film growth orientation thus frequently exhibits a transformation, owing to multiple possibilities caused by incompatible in-plane structural symmetry. Nevertheless, the detailed mechanism of the transformation has not yet been fully explored. Here we thoroughly probe the heteroepitaxially grown hexagonal zinc oxide (ZnO) films on cubic (001)-magnesium oxide (MgO) substrates using advanced scanning transition electron microscopy, X-ray diffraction and first principles calculations, revealing two distinct interface models of (001) ZnO/(001) MgO and (100) ZnO/(001) MgO. We have found that the structure alternatives are controlled thermodynamically by the nucleation, while kinetically by the enhanced Zn adsorption and O diffusion upon the phase transformation. This work not only provides a guideline for the interface fabrication with distinct crystalline phases but also shows how polar and non-polar hexagonal ZnO films might be manipulated on the same cubic substrate.
    Matched MeSH terms: Zinc Oxide
  3. Yu L, Lu M, Zhang W, Alarfaj AA, Hirad AH, Zhang H
    Microb Pathog, 2020 Apr;141:103960.
    PMID: 31953224 DOI: 10.1016/j.micpath.2019.103960
    BACKGROUND: Mycoplasma pneumoniae (MP) is a common cause of community-acquired pneumonia (CAP) among the children and adults that results upper and lower respiratory tract infections.

    OBJECTIVE: This study was aimed to inspect the ameliorative action of A. chinensis synthesized ZnONPs against M. pneumoniae infected pneumonia mice model.

    MATERIALS AND METHODS: ZnO NPs was synthesized from Albizia chinensis bark extract and characterized by UV-Vis spectroscopy, Fourier Transform Infrared (FTIR), Transmission Electron Microscopy (TEM), energy dispersive X-ray (EDX) and atomic force microscope (AFM) analyses. The antibacterial effectual of synthesized ZnONPs were examined against clinical pathogens. The pneumonia was induced to BALB/c mice via injecting the M. pneumoniae and treated with synthesized ZnONPs, followed by the total protein content, total cell counts and inflammatory mediators level was assessed in the BALF of experimental animals. The Histopathological investigation was done in the lung tissues of test animals.

    RESULTS: The outcomes of this work revealed that the formulated ZnONPs was quasi-spherical, radial and cylindrical; the size was identified as 116.5 ± 27.45 nm in diameter. The in vitro antimicrobial potential of formulated ZnO-NPs displayed noticeable inhibitory capacity against the tested fungal and bacterial strains. The administration of synthesized ZnO-NPs in MP infected mice model has significantly reduced the levels of total protein, inflammatory cells, inflammatory cytokines such as IL-1, IL-6, IL-8, tumour necrosis factor-alpha (TNF-a) and transforming growth factor (TGF). Besides, the histopathological examination of MP infected mice lung tissue showed the cellular arrangements were effectively retained after administration of synthesized ZnO-NPs.

    CONCLUSION: In conclusion, synthesized ZnO-NPs alleviate pneumonia progression via reducing the level of inflammatory cytokines and inflammatory cells in MP infected mice model.

    Matched MeSH terms: Zinc Oxide/chemistry*
  4. Naseem T, Bibi F, Arif S, Waseem M, Haq S, Azra MN, et al.
    Molecules, 2022 Oct 22;27(21).
    PMID: 36363976 DOI: 10.3390/molecules27217152
    In this work, graphene oxide (GO) and its reduced graphene oxide-zinc oxide nanocomposite (rGO-ZnO) was used for the removal of Cr (VI) from aqueous medium. By employing a variety of characterization techniques, morphological and structural properties of the adsorbents were determined. The adsorption study was done by varying concentration, temperature, pH, time, and amount of adsorbent. The results obtained confirmed that rGO-ZnO is a more economical and promising adsorbent for removing Cr (VI) as compared to GO. Kinetic study was also performed, which suggested that sorption of Cr (VI) follows the pseudo-first-order model. For equilibrium study, non-linear Langmuir was found a better fitted model than its linearized form. The maximum adsorption capacity calculated for GO and rGO-ZnO nanocomposite were 19.49 mg/g and 25.45 mg/g, respectively. Endothermic and spontaneous nature of adsorption was detected with positive values of ΔS (change in entropy), which reflects the structural changes happening at the liquid/solid interface.
    Matched MeSH terms: Zinc Oxide*
  5. Pang WY, Ahmad AL, Zaulkiflee ND
    J Environ Manage, 2019 Nov 01;249:109358.
    PMID: 31450197 DOI: 10.1016/j.jenvman.2019.109358
    The aim of this study is to evaluate the performance and antifouling properties of polyethersulfone (PES) membrane incorporated with dual nanofiller, zinc oxide (ZnO) and multi-walled carbon nanotube (MWCNT). The synergistic effect of the these nanofillers in PES membrane is studied by blending different ratio of ZnO/MWCNT nanofiller into the PES membrane. The fabricated membranes were characterized in terms of cross-section and surface morphology, surface hydrophilicity, pore size and porosity. The filtration performance of the membranes was tested using 50 mg/L humic acid (HA) solution as model solution. SEM image and gravimetric evaluation reported that the incorporation of both MWCNT and ZnO into the PES membrane improved porosity significantly up to 46.02%. Lower water contact angle of PES membrane incorporated with equal ratio of MWCNT and ZnO (PES 3) revealed that it has neat PES membrane properties and more hydrophilic membrane surface than single filler. PES 3 outperform other membranes with excellent HA permeate flux of 40.00 L/m2.h and rejection of 88.51%. Due to hydrophilic membrane surface, PES 3 membrane demonstrate efficient antifouling properties with lower relative flux reduction (RFR) and higher flux recovery ratio (FRR). PES 3 also showed notable antibacterial properties with less bacterial attached to the membrane compared to neat PES membrane (PES 0).
    Matched MeSH terms: Zinc Oxide*
  6. Ghazali MS, Zakaria A, Rizwan Z, Kamari HM, Hashim M, Zaid MH, et al.
    Int J Mol Sci, 2011;12(3):1496-504.
    PMID: 21673903 DOI: 10.3390/ijms12031496
    The optical band-gap energy (E(g)) is an important feature of semiconductors which determines their applications in optoelectronics. Therefore, it is necessary to investigate the electronic states of ceramic ZnO and the effect of doped impurities under different processing conditions. E(g) of the ceramic ZnO + xBi(2)O(3) + xTiO(2), where x = 0.5 mol%, was determined using a UV-Vis spectrophotometer attached to a Reflectance Spectroscopy Accessory for powdered samples. The samples was prepared using the solid-state route and sintered at temperatures from 1140 to 1260 °C for 45 and 90 minutes. E(g) was observed to decrease with an increase of sintering temperature. XRD analysis indicated hexagonal ZnO and few small peaks of intergranular layers of secondary phases. The relative density of the sintered ceramics decreased and the average grain size increased with the increase of sintering temperature.
    Matched MeSH terms: Zinc Oxide/chemistry*
  7. Barahuie F, Hussein MZ, Abd Gani S, Fakurazi S, Zainal Z
    Int J Nanomedicine, 2014;9:3137-49.
    PMID: 25061291 DOI: 10.2147/IJN.S59541
    BACKGROUND: We characterize a novel nanocomposite that acts as an efficient anticancer agent.

    METHODS: This nanocomposite consists of zinc layered hydroxide intercalated with protocatechuate (an anionic form of protocatechuic acid), that has been synthesized using a direct method with zinc oxide and protocatechuic acid as precursors.

    RESULTS: The resulting protocatechuic acid nanocomposite (PAN) showed a basal spacing of 12.7 Å, indicating that protocatechuate was intercalated in a monolayer arrangement, with an angle of 54° from the Z-axis between the interlayers of the zinc layered hydroxide, and an estimated drug loading of about 35.7%. PAN exhibited the properties of a mesoporous type material, with greatly enhanced thermal stability of protocatechuate as compared to its free counterpart. The presence of protocatechuate in the interlayers of the zinc layered hydroxide was further supported by Fourier transform infrared spectroscopy. Protocatechuate was released from PAN in a slow and sustained manner. This mechanism of release was well represented by a pseudo-second order kinetics model. PAN has shown increased cytotoxicity compared to the free form of protocatechuic acid in all cancer cell lines tested. Tumor growth suppression was extensive, particularly in HepG2 and HT29 cell lines.

    CONCLUSION: PAN is suitable for use as a controlled release formulation, and our in vitro evidence indicates that PAN is an effective anticancer agent. PAN may have potential as a chemotherapeutic drug for human cancer.

    Matched MeSH terms: Zinc Oxide/chemistry*
  8. AWANG R, SITI N.H.M. DAUD, CHI CY, MOHAMMAD HAFIZUDDIN HAJI JUMALI, ZALITA Z
    Sains Malaysiana, 2013;42:1663-1670.
    Filem nipis ZnO terdop Ga (ZnO:Ga) disediakan menggunakan teknik sol-gel dan salutan berputar. Ga didopkan kepada ZnO dengan peratusan berat (wt. %) yang berbeza iaitu 0, 2, 4, 6 dan 8 wt. %. Kesan pengedopan Ga ke atas struktur dan sifat optik filem nipis ZnO dikaji. Pencirian struktur filem nipis ini dilakukan menggunakan kaedah pembelauan sinar-X (XRD), mikroskop imbasan elektron pancaran medan (FESEM) dan mikroskop daya atom (AFM). Pencirian sifat optik filem nipis pula dilakukan menggunakan spektroskopi ultraungu cahaya nampak (UV-VIS) dan fotoluminesen (PL). Ujian XRD mengesahkan kesemua sampel berstruktur wurtzit. Saiz kristalit ZnO mengecil dengan peningkatan peratusan berat Ga seterusnya mengurangkan kekasaran permukaan filem. Pengedopan Ga menunjukkan peratus transmisi cahaya pada panjang gelombang 300 - 380 nm bertambah berbanding filem nipis ZnO tanpa dop. Nilai jurang tenaga optik, Eg dan keamatan PL filem nipis ZnO meningkat apabila pengedopan Ga dilakukan. Hasil kajian ini menunjukkan saiz kristalit yang lebih kecil memberi kesan ke atas sifat optik sampel pada peratus pengedopan Ga 0-6%. Pada peratus pengedopan Ga yang lebih tinggi, kesan transformasi struktur menjadi lebih dominan dalam mempengaruhi nilai Eg.
    Matched MeSH terms: Zinc Oxide
  9. Hutagalung, Sabar D., Eng, Siew T., Zainal A. Ahmad, Ishak Mat, Yussof Wahab
    MyJurnal
    One-dimensional nanostructure materials are very attractive because of their electronic and optical properties depending on their size. It is well known that properties of material can be tuned by reducing size to nanoscale because at the small sizes, that they behave differently with its bulk materials and the band gap will control by the size. The tunability of the band gap makes nanostructured materials useful for many applications. As one of the wide band gaps semiconductor compounds, zinc selenide (ZnSe) nanostructures (nanoparticles, nanowires, nanorods) have received much attention for the application in optoelectronic devices, such as blue laser diode, light emitting diodes, solar cells and IR optical windows. In this study, ZnSe nanostructures have been synthesized by reduction process of zinc selenate using hydrazine hydrate (N2H4.2H2O). The reductive agent of hydrazine hydrate was added to the starting materials of zinc selenate were heat treated at 500 o C for 1 hour under argon flow to form onedimensional nanostructures. The SEM and TEM images show the formation of nanocompositelike structures, which some small nanobars and nanopellets stick to the rod. The x-ray diffraction and elemental composition analysis confirm the formation of mixture zinc oxide and zinc selenide phases.
    Matched MeSH terms: Zinc Oxide
  10. Ramli M, Hussein MZ, Yusoff K
    Int J Nanomedicine, 2013;8:297-306.
    PMID: 23345976 DOI: 10.2147/IJN.S38858
    A new organic-inorganic nanohybrid based on zinc-layered hydroxide intercalated with an anti-inflammatory agent was synthesized through direct reaction of salicylic acid at various concentrations with commercially available zinc oxide. The basal spacing of the pure phase nanohybrid was 15.73 Å, with the salicylate anions arranged in a monolayer form and an angle of 57 degrees between the zinc-layered hydroxide interlayers. Fourier transform infrared study further confirmed intercalation of salicylate into the interlayers of zinc-layered hydroxide. The loading of salicylate in the nanohybrid was estimated to be around 29.66%, and the nanohybrid exhibited the properties of a mesoporous-type material, with greatly enhanced thermal stability of the salicylate compared with its free counterpart. In vitro cytotoxicity assay revealed that free salicylic acid, pure zinc oxide, and the nanohybrid have a mild effect on viability of African green monkey kidney (Vero-3) cells.
    Matched MeSH terms: Zinc Oxide/pharmacology; Zinc Oxide/chemistry
  11. Jahan S, Alias YB, Bakar AFBA, Yusoff IB
    J Environ Sci (China), 2018 Oct;72:140-152.
    PMID: 30244741 DOI: 10.1016/j.jes.2017.12.022
    The toxicity and kinetic uptake potential of zinc oxide (ZnO) and titanium dioxide (TiO2) nanomaterials into the red bean (Vigna angularis) plant were investigated. The results obtained revealed that ZnO, due to its high dissolution and strong binding capacity, readily accumulated in the root tissues and significantly inhibited the physiological activity of the plant. However, TiO2 had a positive effect on plant physiology, resulting in promoted growth. The results of biochemical experiments implied that ZnO, through the generation of oxidative stress, significantly reduced the chlorophyll content, carotenoids and activity of stress-controlling enzymes. On the contrary, no negative biochemical impact was observed in plants treated with TiO2. For the kinetic uptake and transport study, we designed two exposure systems in which ZnO and TiO2 were exposed to red bean seedlings individually or in a mixture approach. The results showed that in single metal oxide treatments, the uptake and transport increased with increasing exposure period from one week to three weeks. However, in the metal oxide co-exposure treatment, due to complexation and competition among the particles, the uptake and transport were remarkably decreased. This suggested that the kinetic transport pattern of the metal oxide mixtures varied compared to those of its individual constituents.
    Matched MeSH terms: Zinc Oxide/toxicity*; Zinc Oxide/chemistry
  12. Abdollahi Y, Abdullah AH, Zainal Z, Yusof NA
    Int J Mol Sci, 2012;13(1):302-15.
    PMID: 22312253 DOI: 10.3390/ijms13010302
    Photocatalytic degradation of p-cresol was carried out using ZnO under UV irradiation. The amount of photocatalyst, concentration of p-cresol and pH were studied as variables. The residual concentration and mineralization of p-cresol was monitored using a UV-visible spectrophotometer and total organic carbon (TOC) analyzer, respectively. The intermediates were detected by ultra high pressure liquid chromatography (UPLC). The highest photodegradation of p-cresol was observed at 2.5 g/L of ZnO and 100 ppm of p-cresol. P-cresol photocatalytic degradation was favorable in the pH range of 6-9. The detected intermediates were 4-hydroxy-benzaldehyde and 4-methyl-1,2-benzodiol. TOC studies show that 93% of total organic carbon was removed from solution during irradiation time. Reusability shows no significant reduction in photocatalytic performance in photodegrading p-cresol.
    Matched MeSH terms: Zinc Oxide/chemistry*
  13. Abdollahi Y, Abdullah AH, Gaya UI, Zainal Z, Yusof NA
    Environ Technol, 2012 Jun;33(10-12):1183-9.
    PMID: 22856288
    The effective removal of o-cresol is currently both an environmental and economic challenge. ZnO is not only an efficient photocatalyst but is also cost effective, as its photoabsorption can extend from the ultraviolet (UV) to the visible range thereby allowing the use of inexpensive visible light sources, such as sunlight. The principal objective of the present work is to investigate the visible light-driven removal of o-cresol from aqueous solution in the presence of 1.0 wt% Mn-doped ZnO. To measure the efficiency ofphotodegradation, the variables studied included the amount ofphotocatalyst, concentration of o-cresol, pH and irradiation time. The concentration ofo-cresol and residual organic carbon was monitored using a UV-visible spectrophotometer, ultra high-pressure liquid chromatography and a total organic carbon analyser. The optimum conditions under which the photodegradation of o-cresol was most favourable corresponded to 1.5 g/l ZnO, 35 ppm o-cresol and pH 9. The ZnO-1 wt% Mn photoprocess has demonstrated reusability for more than three times, which warrants its scale-up from laboratory- to in industrial-scale application.
    Matched MeSH terms: Zinc Oxide/chemistry
  14. Thong YL, Messer HH, Zain RB, Saw LH, Yoong LT
    Dent Traumatol, 2009 Aug;25(4):386-93.
    PMID: 19459923 DOI: 10.1111/j.1600-9657.2008.00631.x
    Progressive replacement resorption following delayed replantation of avulsed teeth has proved to be an intractable clinical problem. A wide variety of therapeutic approaches have failed to result in the predictable arrest of resorption, with a good long-term prognosis for tooth survival. Bisphosphonates are used in the medical management of a range of bone disorders and topically applied bisphosphonate has been reported to inhibit root resorption in dogs. This study evaluated the effectiveness of a bisphosphonate (etidronate disodium) as an intracanal medicament in the root canals of avulsed monkey teeth, placed before replantation after 1 h of extraoral dry storage. Incisors of six Macaca fascicularis monkeys were extracted and stored dry for 1 h. Teeth were then replanted after canal contamination with dental plaque (negative control) or after root canal debridement and placement of etidronate sealed in the canal space. A positive control of calcium hydroxide placed 8-9 days after replantation was also included. All monkeys were sacrificed 8 weeks later and block sections were prepared for histomorphometric assessment of root resorption and periodontal ligament status. Untreated teeth showed the greatest extent of root resorption (46% of the root surface), which was predominantly inflammatory in nature. Calcium hydroxide treated teeth showed the lowest overall level of resorption (<30% of the root surface), while the bisphosphonate-treated group was intermediate (39%). Ankylosis, defined as the extent of the root surface demonstrating direct bony union to both intact and resorbed root surface, was the lowest in the untreated control group (15% of the root surface), intermediate in the calcium hydroxide group (27%) and the highest in the bisphosphonate group (41%). Bony attachment to the tooth root was divided approximately equally between attachment to intact cementum and to previously resorbed dentin. Overall, bisphosphonate resulted in a worse outcome than calcium hydroxide in terms of both root resorption and ankylosis.
    Matched MeSH terms: Zinc Oxide-Eugenol Cement/therapeutic use
  15. Lee HB, Ginting RT, Tan ST, Tan CH, Alshanableh A, Oleiwi HF, et al.
    Sci Rep, 2016 09 02;6:32645.
    PMID: 27587295 DOI: 10.1038/srep32645
    Anion passivation effect on metal-oxide nano-architecture offers a highly controllable platform for improving charge selectivity and extraction, with direct relevance to their implementation in hybrid solar cells. In current work, we demonstrated the incorporation of fluorine (F) as an anion dopant to address the defect-rich nature of ZnO nanorods (ZNR) and improve the feasibility of its role as electron acceptor. The detailed morphology evolution and defect engineering on ZNR were studied as a function of F-doping concentration (x). Specifically, the rod-shaped arrays of ZnO were transformed into taper-shaped arrays at high x. A hypsochromic shift was observed in optical energy band gap due to the Burstein-Moss effect. A substantial suppression on intrinsic defects in ZnO lattice directly epitomized the novel role of fluorine as an oxygen defect quencher. The results show that 10-FZNR/P3HT device exhibited two-fold higher power conversion efficiency than the pristine ZNR/P3HT device, primarily due to the reduced Schottky defects and charge transfer barrier. Essentially, the reported findings yielded insights on the functions of fluorine on (i) surface -OH passivation, (ii) oxygen vacancies (Vo) occupation and (iii) lattice oxygen substitution, thereby enhancing the photo-physical processes, carrier mobility and concentration of FZNR based device.
    Matched MeSH terms: Zinc Oxide
  16. Hussein MZ, Azmin WH, Mustafa M, Yahaya AH
    J Inorg Biochem, 2009 Aug;103(8):1145-50.
    PMID: 19577306 DOI: 10.1016/j.jinorgbio.2009.05.016
    Currently the development of green chemistry approach with the use of biomaterial-based activities of microbial cells in the synthesis of various nanostructures has attracted a great attention. In this study, we report on the use of bacterium, Bacillus cereus as a biotemplating agent for the formation of zinc oxide nanoparticles with raspberry- and plate-like structures through a simple thermal decomposition of zinc acetate by maintaining the original pH of the reaction mixtures. Possible mechanism on the formation of the nanostructures is proposed based on the surface chemistry and biochemistry processes involved organic-inorganic interactions between zinc oxide and the microbial cells.
    Matched MeSH terms: Zinc Oxide/metabolism*; Zinc Oxide/chemistry
  17. Yatongchai C, Placek LM, Curran DJ, Towler MR, Wren AW
    J Biomater Appl, 2015 Nov;30(5):495-511.
    PMID: 26116020 DOI: 10.1177/0885328215592866
    Hydroxyapatite (Ca10(PO4)6(OH)2) is widely investigated as an implantable material for hard tissue restoration due to its osteoconductive properties. However, hydroxyapatite in bulk form is limited as its mechanical properties are insufficient for load-bearing orthopedic applications. Attempts have been made to improve the mechanical properties of hydroxyapatite, by incorporating ceramic fillers, but the resultant composite materials require high sintering temperatures to facilitate densification, leading to the decomposition of hydroxyapatite into tricalcium phosphate, tetra-calcium phosphate and CaO phases. One method of improving the properties of hydroxyapatite is to incorporate bioactive glass particles as a second phase. These typically have lower softening points which could possibly facilitate sintering at lower temperatures. In this work, a bioactive glass (SiO2-CaO-ZnO-Na2O-TiO2) is incorporated (10, 20 and 30 wt%) into hydroxyapatite as a reinforcing phase. X-ray diffraction confirmed that no additional phases (other than hydroxyapatite) were formed at a sintering temperature of 560 ℃ with up to 30 wt% glass addition. The addition of the glass phase increased the % crystallinity and the relative density of the composites. The biaxial flexural strength increased to 36 MPa with glass addition, and there was no significant change in hardness as a function of maturation. The pH of the incubation media increased to pH 10 or 11 through glass addition, and ion release profiles determined that Si, Na and P were released from the composites. Calcium phosphate precipitation was encouraged in simulated body fluid with the incorporation of the bioactive glass phase, and cell culture testing in MC-3T3 osteoblasts determined that the composite materials did not significantly reduce cell viability.
    Matched MeSH terms: Zinc Oxide/chemistry*
  18. Iqbal A, Saidu U, Adam F, Sreekantan S, Yahaya N, Ahmad MN, et al.
    Molecules, 2021 Apr 25;26(9).
    PMID: 33923041 DOI: 10.3390/molecules26092509
    In this work, mesoporous TiO2-modified ZnO quantum dots (QDs) were immobilised on a linear low-density polyethylene (LLDPE) polymer using a solution casting method for the photodegradation of tetracycline (TC) antibiotics under fluorescent light irradiation. Various spectroscopic and microscopic techniques were used to investigate the physicochemical properties of the floating hybrid polymer film catalyst (8%-ZT@LLDPE). The highest removal (89.5%) of TC (40 mg/L) was achieved within 90 min at pH 9 due to enhanced water uptake by the LDDPE film and the surface roughness of the hybrid film. The formation of heterojunctions increased the separation of photogenerated electron-hole pairs. The QDs size-dependent quantum confinement effect leads to the displacement of the conduction band potential of ZnO QDs to more negative energy values than TiO2. The displacement generates more reactive species with higher oxidation ability. The highly stable film photocatalyst can be separated easily and can be repeatedly used up to 8 cycles without significant loss in the photocatalytic ability. The scavenging test indicates that the main species responsible for the photodegradation was O2●-. The proposed photodegradation mechanism of TC was demonstrated in further detail based on the intermediates detected by LC-time-of-flight/mass spectrometry (LC/TOF-MS).
    Matched MeSH terms: Zinc Oxide/chemistry
  19. Nur Ain, A.R., Mohd Sabri, M.G., Wan Rafizah, W.A., Nurul Azimah, M.A., Wan Nik, W.B.
    ASM Science Journal, 2018;11(101):56-67.
    MyJurnal
    Corrosion is a natural deterioration process that destructs metal surface. Metal of highly
    protected by passivation layer such as Stainless Steel 316L also undergoes pitting corrosion
    when continuously exposed to aggressive environment. To overcome this phenomenon, application
    of epoxy based coating with addition of zinc oxide- poly (3,4-ethylenedioxythiophene)
    doped with poly (styrene sulphonate) hybrid nanocomposite additive was introduced as
    paint/metal surface coating. The compatibility between these two materials as additive
    was studied by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD),
    Field Emission Scanning Electron Microscopy/Energy-Dispersive X-ray spectroscopy (FESEM/EDX)
    and Transmission Electron Microscopy (TEM) analysis. The effect of nanocomposite
    wt.% in epoxy based coating with immersion duration in real environment on corrosion
    protection performance was analyzed through potentiodynamic polarization analysis. The
    main finding showed that addition of hybrid nanocomposite had increased corrosion protection
    yet enhanced corrosion process when excess additives was loaded into epoxy coating.
    Addition of 2 wt.% ZnO-PEDOT:PSS was found significantly provided optimum corrosion
    protection to stainless steel 316L as the corrosion rate for 0 day, 15 days and 30 days of
    immersion duration is 0.0022 mm/yr, 0.0004 mm/yr and 0.0015 mm/yr; respectively.
    Matched MeSH terms: Zinc Oxide
  20. Ng KH, Chen K, Cheng CK, Vo DN
    J Hazard Mater, 2021 05 05;409:124532.
    PMID: 33221078 DOI: 10.1016/j.jhazmat.2020.124532
    Powdered-photocatalysis of organic wastewater is widely investigated, unfortunately not industrially implemented due to its high energy requirement. Interestingly, such issue may be alleviated via the elimination of mechanical stirring required. Core-shell ZnO-based photocatalysts were developed herein, subsequently demonstrated efficient photocatalytic activities in the absence of mechanical stirring. Results show that the developed SiO2-cored ZnO photocatalyst are highly crystalline, while significantly smaller than coreless, pure ZnO due to the multi-point crystallization prompted. Additionally, it is also inherited with considerable buoyancy ability from SiO2-core in the absence of mechanical stirring, concurrently rendered with UV-active properties due to its ZnO-shell. Experimentally, 55% of particles of ZnO_0.0025 (0.0025 mol of ZnO-deposition) were found stably suspended for 60 min in liquid substrate, as opposed to the instant-settling of pure ZnO particles. In term of photocatalytic activity, ZnO_0.01 manifested the best methylene blue (MB) degradation with 150 mL/min of O2-bubbling. 67.63% of MB was degraded with photocatalyst loading of 0.2 g/L after 120 min UV-irradiation, simultaneously recorded the highest pseudo-first order reaction constant of 9.636 × 10-3 min-1. As summary, the auto-suspending photocatalysis conceptualized in current study offers a high possibility in reducing energy requirement for photo-treatment of wastewater, hence advocating its industrialization potential in near future.
    Matched MeSH terms: Zinc Oxide
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