Fabrication of zinc oxide nanorods modified activated carbon cloth electrode for desalination of brackish water using capacitive deionization approach

Nanomaterial grafted polymorphous activated carbon cloth surface for antibacterial, capacitive deionization and oil spill cleaning applications

Brackish water desalination by capacitive deionization using zinc oxide micro/nanostructures grafted on activated carbon cloth electrodes

Zinc oxide (ZnO) is an emerging optoelectronic material in large area electronic applications that are due to its various functional behaviors. We present the fabrication and characterizations of ZnO nanorods. The ZnO nanorods were synthesized using sol-gel hydrothermal technique on oxidized silicon (Si) substrates. In the fabrication of ZnO nanorods, the oxidized Si substrates were immersed in ZnO aqueous solution for different durations ranging from 3 hours to 5 hours. The surface morphologies of the ZnO nanorods were examined using scanning electron microscope (SEM). In order to investigate the structural properties, the ZnO nanorods were measured using X-ray diffractometer (XRD). The optical properties were measured using ultraviolet-visible (UV-Vis) spectroscopy. The effect of the immerse duration on the material properties of the realized ZnO nanorods will be revealed and discussed in this paper.

Unravelling the key contribution of a modified zinc oxide nanostructures on activated carbon cloth material for removal of Cu2+ in different configurations of capacitive deionization system

Removal of heavy metal ions by capacitive deionization: Effect of surface modification on ions adsorption

The zinc oxide (ZnO) nanorods (NRs) (4 hours) and nanowires (NWs) (12 and 24 hours) were synthesized on the magnesium ZnO (MgZnO) seed layer by using sol-gel immersion method. The ZnO NRs and NWs were characterized by FESEM, XRD, UV-Vis and four-point probe measurement. The FESEM images showed uniform, dense and vertically aligned structure. The smallest diameter observed in ZnO NWs (24 hours) in the range ∼ 47.6-99.2 nm. The XRD spectra also presented the c-axis growth of ZnO NRs and NWs. The ZnO NWs (24 hours) demonstrated higher transmittance and electrical conductivity of ∼77.8% and 2.6 × 10−1 S cm−1 as compared to ZnO NRs of 66.7% and 1.1 ×10−2 S cm−1, respectively. Therefore, the ZnO NWs (24 hours) showed a good structure to be applied in solar cells and UV sensor applications.

In this study, homojunction light-emitting diodes (LEDs) based on n-type zinc oxide (ZnO) nanorods (NRs)/silver (Ag)-doped p-type ZnO NRs were successfully fabricated by low-temperature solution process. Here, the Ag thin film used as a template and dopant source for the growth of p-type ZnO NRs as well as a bottom electrode. The Ag-doped p-type ZnO NRs were synthesized using an ammonium hydroxide solution, which possesses a high pH value of 11.6 to dissolve the Ag film and form Ag+ ions in the solution. Using these Ag-doped p-type ZnO NRs as a template, n-type ZnO NRs were epitaxially grown on top of them at 90 °C to form ZnO NRs p–n homojunction. These ZnO NRs p–n homojunction LEDs showed a typical rectifying behavior with a turn-on voltage of 3.5 V and a high rectifying ratio of 1.5 × 105 at 5 V. Furthermore, under a forward bias of 9 V, the LED exhibited a wide yellow electroluminescence emission centered at 645 nm, which was attributed to the various emission sites of ZnO deep-level defects. This stu...

Methicillin-resistant Staphylococcus aureus (MRSA) causes life-threatening infections. Zinc oxide is well known as an effective antibacterial drug against many bacterial strains. We investigated the performance of zinc oxide nanorods synthesized by Albmiun as a biotemplate as an antibacterial drug in this study; the fabrication of zinc oxide nanorods was synthesized by sol-gel methods. We performed physicochemical characterization of zinc oxide nanorods by physiochemical techniques such as FTIR spectroscopy, X-ray diffraction, and TEM and investigation of their antimicrobial toxicity efficiency by MIC, ATPase activity assay, anti-biofilm activity, and kill time assays, as well as the mecA, mecR1, blaR1, blaZ, and biofilm genes (ica A, ica D, and fnb A) by using a quantitative RT-PCR assay and the penicillin-binding protein 2a (PBP2a) level of MRSA by using a Western blot. The data confirmed the fabrication of rod-shaped zinc oxide nanorods with a diameter in the range of 50 nm, which emphasized the formation of zinc oxide nanoparticles with regular shapes. The results show that zinc oxide nanorods inhibited methicillin-resistant S. aureus effectively. The MIC value was 23 μg/mL. The time kill of ZnO-NRs against MRSA was achieved after 2 h of incubation at 4MIC (92 μg/mL) and after 3 h of incubation at 2MIC (46 μg/mL), respectively. The lowest concentration of zinc oxide nanorods with over 75% biofilm killing in all strains tested was 32 μg/mL. Also, we examined the influence of the zinc oxide nanorods on MRSA by analyzing mecA, mecR1, blaR1, and blaZ by using a quantitative RT-PCR assay. The data obtained revealed that the presence of 2× MIC (46 μg/mL) of ZnO-NRs reduced the transcriptional levels of blaZ, blaR1, mecA, and mecR1 by 3.4-fold, 3.6-fold, 4-fold, and 3.8-fold, respectively. Furthermore, the gene expression of biofilm encoding genes (ica A, ica B, ica D, and fnb A) was tested using quantitative real-time reverse transcriptase-polymerase chain reaction (rt-PCR). The results showed that the presence of 2× MIC (46 μg/mL) of ZnO-NRs reduced the transcriptional levels of ica A, ica B, ica D, and fnb A. Also, the PBP2a level was markedly reduced after treatment with ZnO-NRs.

This work focuses on Zinc Oxide (ZnO) nanorods as the photoanode in Dye-Sensitized Solar Cell (DSSC). The photoanode protects the dye molecules and enables the energetic absorption of photogenerated electrons from the active state of the natural dye. The primary goals are the fabrication of ZnO nanorods on ITO, the investigation of the structural, optical and electrical properties of the synthesized ZnO nanorods, and the performance evaluation of the ZnO nanorods-based DSSC. The hydrothermal process is used to produce ZnO nanorods at an annealing temperature of 90°C. For structural characterization, a scanning electron microscope (SEM) with specific field ranges and magnification utilized to analyze and evaluate the composition of ZnO nanotubes. X-ray diffraction measurements with data processing are carried out in order to classify the crystalline process of the materials and provide information on cell unit size. Alternatively, UV analysis is used to demonstrate optical characteristics. Ruthenium was implemented as a natural dye, and four samples of ZnO nanorods with different development durations were tested for current density and voltage using an automated multimeter and UV irradiation. Calculations are performed for both current and voltage outputs of the DSSC.

In this study, the zinc oxide (ZnO) nanorods (NRs) arrays were synthesized and applied in field-effect transistors (FET). The single crystalline ZnO NRs arrays were synthesized on p+-Si substrate without seed layer by using the low-cost and low-temperature hydrothermal method. The substrate surface was functionalized by hydrofluoric acid (HF) and self-assembled monolayer (SAM) of octadecyltrimethoxysilane [(CH 3 (CH 2 ) 17 Si(OCH 3 ) 3 , ODS]. ZnO NRs were characterized by x-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM). The results of FESEM and XRD indicate that it is possible to grow high-isotropic one-dimensional ZnO NRs arrays on the functionalized p+-Si surface. The fabrication and characteristics of single ZnO NR FET was done. The ZnO NR is n-type semiconductor material determined by FET operation mode. The single ZnO NRs FET possesses the electron mobility, electron concentration, and resistivity of 40.16 cm2/Vs, 1.06×1015 cm−3, and 1.46×102 Ω-cm, respectively.

Capacitive deionization (CDI) is a promising and cost-effective technology that is currently being widely explored for removing dissolved ions from saline water. This research developed materials based on activated carbon (AC) materials modified with zinc oxide (ZnO) nanorods and used them as high-performance CDI electrodes for water desalination. The as-prepared electrodes were characterized by cyclic voltammetry, and their physical properties were studied through SEM and XRD. ZnO-coated AC electrodes revealed a better specific absorption capacity (SAC) and an average salt adsorption rate (ASAR) compared to pristine AC, specifically with values of 123.66 mg/g and 5.06 mg/g/min, respectively. The desalination process was conducted using a 0.4 M sodium chloride (NaCl) solution with flow rates from 45 mL/min to 105 mL/min under an applied potential of 1.2 V. Furthermore, the energy efficiency of the desalination process, the specific energy consumption (SEC), and the maximum and minimum of the effluent solution concentration were quantified using thermodynamic energy efficiency (TEE). Finally, this work suggested that AC/ZnO material has the potential to be utilized as a CDI electrode for the desalination of saline water.

Zinc oxide (ZnO) nanorod arrays were fabricated on ZnO:Al seeded Si substrates with various reaction temperatures using a low temperature hydrothermal method. The morphology and structure of ZnO nanorod arrays were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). It reveals that the ZnO nanorods grow vertically on Si surface with (002) preferential orientation. The transmittance spectra show the ZnO nanorod arrays fabricated at low temperatures have high transmittance in the visible region and decrease with reaction temperature increasing. Moreover, the same trend was also observed in the reflectance spectra of the ZnO nanorod arrays. The optimal reaction temperature is of 120 °C for ZnO nanorod arrays with high transmittance (~80%) and low reflectance (~10%) in the visible region. The superior optical properties make ZnO nanorod arrays promising for applications as transparent electrodes.

Improved desalination by zinc oxide nanorod induced electric field enhancement in capacitive deionization of brackish water

Vertically aligned zinc oxide (ZnO) nanorods (NRs) were grown by the low-temperature hydrothermal method on graphene oxide (GO) coated FTO substrates, where GO was directly deposited on fluorine doped tin oxide (FTO) substrates using hydrogen (H(2), 65 sccm) and methane (CH(4), 50 sccm) through hot filament chemical vapor deposition (HFCVD) technique. The vertically aligned ZnO NRs were applied as effective photoanode for the fabrication of efficient dye sensitized solar cells (DSSCs). Highly uniform ZnO NRs were grown on GO deposited FTO substrate with the average length of ∼2-4 μm and diameter of ∼200-300 nm. The possible mechanism of grown ZnO NRs clearly revealed the significant role of GO on FTO in architecting the aligned growth of ZnO NRs. The grown vertically aligned ZnO NRs possessed a typical wurtzite hexagonal crystal structure. The structural and the optical studies confirmed the formation of partial hydrogen bonding between surface functional groups of GO and ZnO NRs. A solar-to-electricity conversion efficiency of ∼2.5% was achieved by DSSC fabricated with ZnO NRs deposited on graphene oxide (GO-ZnO NRs) thin film photoanode. The presence of GO on FTO substrate expressively increased the surface area of GO-ZnO photoanode, which resulted in high dye loading as well as high light harvesting efficiency and thus ensued the increased photocurrent density and the improved performance of DSSCs.

Improvement in capacitive deionization function of activated carbon cloth by titania modification