Exploration of rice husk ash as a green corrosion inhibitor immersed in NH4Cl 7.5 % solution.

The study reports the development of a liquid smoke solution of rice husk ash (RHA) as a green corrosion inhibitor in NH4Cl solution in approaching corrosion protection for refinery facilities. The recent utilization of RHA has a partial solution to address the possible chemical to form a filming layer to disconnect bare metal and their environment. This work prepared the RHA solution by condensing the RHA vapor before adding it to various concentrations. The corrosion test of potentiodynamic and electrochemicals intends to discover the inhibitor's corrosion resistance before examining the electronic transition corresponding to the contribution of several functional groups using Ultraviolet Visible (UV-Vis) and Fourier-Transform Infrared Spectroscopy (FTIR). Surface evaluation intends to unveil the nature of the corrosion by utilizing the Scanning Electronic and Atomic Force Microscope. The corrosion test result shows the depression of corrosion rate to 0.120 mmpy with high efficiency beyond 96 % in the addition of 7.5 ppm RHA inhibitor. The greater Nyquist semicircle diameter at high concentrations increases the adsorption of the RHA on the surface of C1018. The electronic transition of n-π* and π -π* shows an extensive contribution of C[bond, double bond]C, C[bond, double bond]O, and -OH based on the UV-Vis and FTIR test. The formation of a complex compound of Fe-(NH4Cl-RHA)n blocks the corrosion active sites to reduce the corrosion. This study paves the way for using RHA as an organic compound under NH4Cl conditions, such as in a refinery process facility.

Graphene oxide doping in tropical almond (terminalia catappa L.) fruits extract mediated green synthesis of TiO2 nanoparticles for improved DSSC power conversion efficiency.

The power conversion efficiency (PCE) of a dye-sensitized solar cell (DSSC) device depends on its semiconductor characteristics. Titanium dioxide (TiO2) nanoparticles are a semiconductor material commonly used in the DSSC device whose characteristics depend on the synthesis process. There are many routes to synthesize TiO2, however, they typically involve hazardous approaches, which may cause risk to the environment. Green synthesis is an environmentally friendly alternative method using ecological solvents that eliminates toxic waste and reduces energy consumption. In this work, tropical almond (Terminalia catappa L.) was used as a natural capping agent in the green synthesis to control the growth of TiO2. In addition, graphene oxide (GO) was used as a dopant to increase the performance of DSSC device. The results are convincing, in which the addition of 0.0017 % GO doping in tropical almond extract mediated green synthesis of TiO2 improved the PCE from 0.85 % to 1.72 %. These results suggest that GO-modified TiO2 nanoparticles green synthesized using tropical almond extract have great potential in the fabrication of DSSC devices with good PCE, low cost, and low environmental impact.

Selective non-enzymatic uric acid sensing in the presence of dopamine: electropolymerized poly-pyrrole modified with a reduced graphene oxide/PEDOT:PSS composite.

A highly selective electrochemical sensor based on a molecularly imprinted polymer (MIP) to be developed for uric acid detection in the presence of dopamine as an interference molecule was demonstrated in this study. This non-enzymatic uric acid sensor was developed by electropolymerizing poly-pyrrole onto a composite of electrochemically reduced graphene oxide (ErGO) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) on a glassy carbon electrode (GCE) to give MIP/ErGO/PEDOT:PSS electrodes. The structural properties, surface morphology, and electrochemical interface of this fabricated uric acid sensor was then characterized using infrared spectroscopy, scanning electron microscopy, atomic force microscopy, and electrochemical impedance spectroscopy. This fabricated non-enzymatic electrochemical sensor (MIP/ErGO/PEDOT:PSS modified GCE) also showed excellent analytical performance at the optimum ratio of monomer/template concentration and optimized electropolymerization conditions, for example in the low concentration range of 0.1-100 µM with a detection limit of 0.05 µM towards uric acid detection in the presence of dopamine. Furthermore, this fabricated uric acid sensor also exhibited good reproducibility and stability for uric acid measurements in the presence of dopamine for 5 consecutive days. In addition, this sensor demonstrates highly selective detection of uric acid in the presence of several interfering species such as dopamine, urea, glucose, magnesium ions, and ascorbic acid. This fabricated uric acid sensor ultimately showed satisfactory uric acid measurement in samples of human urine and is expected to be used in early-stage disease diagnosis.

ZnO-based antimicrobial coatings for biomedical applications.

Rapid transmission of infectious microorganisms such as viruses and bacteria through person-to-person contact has contributed significantly to global health issues. The high survivability of these microorganisms on the material surface enumerates their transmissibility to the susceptible patient. The antimicrobial coating has emerged as one of the most interesting technologies to prevent growth and subsequently kill disease-causing microorganisms. It offers an effective solution a non-invasive, low-cost, easy-in-use, side-effect-free, and environmentally friendly method to prevent nosocomial infection. Among antimicrobial coating, zinc oxide (ZnO) stands as one of the excellent materials owing to zero toxicity, high biocompatibility to human organs, good stability, high abundancy, affordability, and high photocatalytic performance to kill various infectious pathogens. Therefore, this review provides the latest research progress on advanced applications of ZnO nanostructure-based antibacterial coatings for medical devices, biomedical applications, and health care facilities. Finally, future challenges and clinical practices of ZnO-based antibacterial coating are addressed.