scholarly journals Copper corrosion inhibitors based on polyvinyl alcohol and silver nanoparticles

2019 ◽  
Vol 25 (3) ◽  
pp. 267-275 ◽  
Author(s):  
Roxana Grecu ◽  
Adriana Samide ◽  
Gabriela Iacobescu ◽  
Nicoleta Cioateră ◽  
Alexandru Popescu

Polyvinyl alcohol (PVA) and silver nanoparticles/poly(vinyl) alcohol system (nAg/PVA) were investigated as copper corrosion inhibitors in hydrochloric acid solution by electrochemical measurements, such as potentiodynamic polarization and cyclic voltammetry associated with the atomic force microscopy (AFM) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS) analysis. The potentiodynamic curves processed as a semilogarithmic diagram were employed for corrosion current density (icorr) computing that reached the highest value for copper corrosion in uninhibited hydrochloric acid solution and the lowest value in nAg/PVA inhibitor presence, resulting in a picked-up inhibition performance, greater than 95%. Recording ten cycles of CV, the initiation, development and stability of upper-layer formed on the copper surface in the presence of inhibitors was confirmed. It can be asserted that PVA acts by the adsorption of Cu(II)-PVA complexes or crosslinked PVA-copper aggregates and additionally, in the presence of nAg/PVA of some compounds involving silver attached to PVA. AFM 3D images showed completely different morphologies of the copper surface layers formed in the absence and presence of inhibitors. Just like AFM, a more regular and uniform arrangement of the surface layer, due to the silver interconnected to PVA macromolecular chain, was displayed by scanning electron microscopy (SEM) images.

1999 ◽  
Vol 23 (5) ◽  
pp. 299-299
Author(s):  
Rita Giovannetti ◽  
Vito Bartocci ◽  
Laura Petetta

The effect of Li+, K+, NH+4, Ca2+ or Sr2+ in the extraction of mercury(II) as chloro-complexes from solutions in hydrochloric acid with dibenzo-18-crown-6 (DB18C6) into benzene and the stoichiometries of the reactions have been studied. The crystalline extracted species were characterized by morphological and microanalysis measurements by scanning electron microscopy and energy dispersive X-ray spectrometry respectively.


2013 ◽  
Vol 690-693 ◽  
pp. 1029-1032
Author(s):  
Xiao Qiang Li ◽  
Li Juan Lan

Active carbon modified by hydrochloric acid was prepared with impregnation method. The synthesized material was characterized by scanning electron microscopy. It was proved that plenty of pores with diameter of about 5-10μm were exist on the surface of active carbon. The adsorption process with toluene was performed over the modified active carbon to investigate the adsorptive efficiency. For comparison, other porous materials were also performed the adsorption experiment. The results showed that active carbon modified by hydrochloric acid has high adsorptive efficiency for toluene. The results proved that adsorptive performance of active carbon increased with the hydrochloric acid concentration.


Author(s):  
S C Joshi ◽  
Utkarsh Kaushik ◽  
Aproova Upadhyaya ◽  
Priyanka Sharma

ABSTRACTObjective: The synthesis of nanoparticles from biological processes is evolving a new era of research interests in nanotechnology. Silver nanoparticlesare usually synthesized by chemicals and physical method, which are quite toxic and flammable in nature. This study deals with an environmentfriendly biosynthesis process of antibacterial silver nanoparticles using Momordica charantia fruit.Methods: AgNO3 (5 mM) was allowed to react with fruit extract of M. charantia. Biosynthesis of AgNPs was optimized by changing temperature,pH, and solvent. The silver nanoparticles so formed were characterized using ultraviolet-visible (UV-VIS) spectroscopy, Fourier transform infraredspectroscopy (FTIR), dynamic light scattering (DLS), atomic force microscope (AFM), and scanning electron microscopy (SEM).Results: UV-VIS spectra show absorption peak between 420 and 430 nm. The FTIR analysis showed the alcoholic, lactam, and nitro group presentin the plant extract, which were responsible for the reduction in AgNPs. The SEM images showed the size distribution of the nanoparticles and theaverage size was found to be 50-100 nm. By DLS analysis and AFM analysis, average sizes of the silver nanoparticles were of 150 nm. The results ofthese analyses confirmed the formation of silver nanoparticles. Silver nanoparticles were tested against Bacillus cereus and Staphylococcus epidermidisstrains using disc diffusion method and were found to be effective.Conclusion: Silver nanoparticles so synthesized in this study using fruit extract of M. charantia are simple, easy, and effective technique of nanoparticlesproduction.Keywords: Silver nanoparticles, Momordica charantia, Optimization, Antibacterial, Atomic force microscope, Scanning electron microscopy.


Nanomedicine ◽  
2019 ◽  
Vol 14 (21) ◽  
pp. 2783-2798
Author(s):  
Ajmal Khan ◽  
Ahmed Al-Harrasi ◽  
Najeeb Ur Rehman ◽  
Rizwana Sarwar ◽  
Touqeer Ahmad ◽  
...  

Aim: Acetyl-11-keto- β-boswellic acid (AKBA) is a potent anti-inflammatory compound limited by its low water solubility and bioavailability. To load AKBA on silver nanoparticles (AgNPs) to improve bioavailability and water solubility of the compound. Materials & methods: AKBA-AgNPs were chemically synthesized and characterized by UV–Vis spectrophotometry, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. AKBA and AKBA-Ag were studied for their sedative-hypnotic and anti-inflammatory efficacies. Results: Pretreatment with AKBA or AKBA-Ag caused significant dose-dependent sedative-hypnotic effects at 5 and 10 mg/kg intraperitoneal. The effects of AKBA-loaded AgNPs caused pronounced changes in mice compared with those of AKBA, and the AKBA-AgNPs demonstrated anti-inflammatory effects that were superior to those of AKBA. Conclusion: The loading of AKBA on nanoparticles improved its pharmacokinetic effects, and capacity for drug delivery.


2018 ◽  
Vol 930 ◽  
pp. 224-229
Author(s):  
Marcos Antônio Guerra ◽  
Jeferson Prado Swerts ◽  
Mei Abe Funcia ◽  
Neide Aparecida Mariano ◽  
Maria Gabriela Nogueira Campos

Polyethylene terephthalate (PET) fiber is a very versatile fiber that can be produced with different properties, such as antimicrobial activity. This study aims to synthesize antimicrobial PET filaments incorporated with silver nanoparticles immobilized in silica (NPAg-Si) by bulk additive method. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) characterized the obtained filaments at concentrations (w/w) of 0.008%, 0.016%, 0.032%, 0.047% and 0.063% NPAg-Si, in order to identify the nanoparticles and analyze their dispersion in the polymeric matrix. Moreover, thermogravimetric analysis (TGA) was carry out to confirm the presence and concentration of the silver nanoparticles in the filaments as well as the thermal stability of the nanocomposites. The bulk addition method was efficient to produce PET-Silver filaments with silver nanoparticles homogeneously dispersed in the PET matrix.


2013 ◽  
Vol 33 (3) ◽  
pp. 257-263 ◽  
Author(s):  
Sreekumar Parambathmadhom Appu ◽  
Sadhan Kumar De ◽  
Massihullah J. Khan ◽  
Mamdouh A. Al-Harthi

Abstract Starch plasticized with glycerol and blended with polyvinyl alcohol (PVA) is recommended for use as a biodegradable material. The present article reports the results of studies of the natural weather ageing of starch/PVA blends having various amounts of glycerol in natural weather conditions of Saudi Arabia, with special reference to morphology and thermal behavior. Neat PVA has been used as a control to understand its behavior in its blend with starch. Differential scanning calorimeter studies indicated that an increase in the exposure time of samples to natural environment increases the crystallinity of PVA due to the breakage of intermolecular hydrogen bonding, thus facilitating the removal of the amorphous portion of the polymers in the blend. Thermogravimetric analysis revealed that an increase in glycerol content enhanced the degradation of the polymer, which is corroborated with the findings from the surface morphology using scanning electron microscopy and Fourier transfer infrared spectroscopy analyses.


1976 ◽  
Vol 55 (1) ◽  
pp. 107-110 ◽  
Author(s):  
Abraham Abramovich ◽  
Ricardo L. Macchi ◽  
Lucía M. Ribas

The surface of tooth enamel that had been left in contact with a phosphoric acid solution or a zinc phosphate cement mix was studied by scanning electron microscopy. Both treatments modified enamel surface topography. The modifications were represented by cavities of varying extension and depth.


Author(s):  
Gabriel N. Chukwueze ◽  
Christian O. Asadu ◽  
Chijioke E. Onu ◽  
Innocent S. Ike

The inhibitive ability of pawpaw, neem and curry leaf extracts on corrosion of mild steel in sulfuric acid solution were investigated in this work. The extracts obtained from their respective leaves, were characterized to determine their phytochemical constituents as well as functional groups present using Fourier Transform Infrared Spectroscopy (FTIR) technique. Weight loss techniques was employed to evaluate the corrosion inhibition efficiency of the leaf extracts. The Scanning Electron Microscopy (SEM) was used to study the morphology of the mild steel before and after corrosion experiments. The process factors studied was exposure time, concentration of leaf extracts (inhibitor) and temperature. The results revealed that the phytochemical constituents of the leaves are capable of inhibiting corrosion due to high concentration of tannins which is responsible for the corrosion inhibition of mild steel. The rate of corrosion decreased with increase in the concentration of the extracts while the inhibition efficiency increased with increase in the concentration of the extracts. Scanning Electron Microscopy (SEM) revealed that the corroded mild steel in the presence of the extracts had smoother surfaces than corroded mild steel in the absence of the extracts. Also, neem leaf extract demonstrated higher potential as corrosion inhibitor than pawpaw and curry leaf extracts.


2020 ◽  
Vol 21 (1) ◽  
pp. 30
Author(s):  
Dewi Mustika Rahim ◽  
Netti Herawati ◽  
Hasri Hasri

ABSTRAK Telah dilakukan penelitian tentang sintesis nanopartikel perak menggunakan bioreduktor ekstrak daun teh hijau (Camellia Sinensis) dengan iradiasi microwave. yang untuk mengetahui pengaruh waktu sintesis dan pengaruh pH stabilizer terhadap sintesis nanopartikel perak ekstrak daun teh hijau dengan iradiasi microwave serta karakterisasinya. Larutan AgNO3 3 mM direduksi menggunakan ekstrak daun teh hijau dan di iradiasi microwave pada variasi waktu sintesis 1-5 menit. Penentuan waktu sintesis optimal menggunakan spektrofotometer UV-Vis diukur setiap 1 menit. Nanopartikel dengan waktu sistesis 4 menit, pH stabilizer menggunakan asam sitrat dan NaOH dengan pH 6-9. Karakterisasi nanopartikel menggunakan instrumen SEM-EDS (Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy) dan PSA (Particle Size Analyzer). Hasil penelitian menunjukkan bahwa waktu sintesis optimal adalah 4 menit. Morfologi nanopatikel perak yang dikarakterisasi menggunakan SEM (Scanning Electron Microscopy) yang dihasilkan cenderung beragregasi. Adanya kecenderungan nanopartikel untuk beragregasi menyebabkan ukuran atau diameter nanopartikel tidak seragam. Ukuran dan distribusi ukuran nanopartikel perak dikarakterisasi menggunakan PSA(Particle Size Analyzer) dihasilkan pada pH 6 antara 31,01 – 402,44 nm dengan rata-rata ukuran sebesar 91 nm, pH 7 antara 35,03 – 740,899 nm dengan rata-rata ukuran sebesar 106,3 nm, pH 8 antara 39,58 – 193,48 nm dengan rata-rata ukuran 71,7, dan pH 9 antara 35,03 – 171,25 nm dengan rata-rata ukuran sebesar 64,4 nm. Disimpulkan bahwa hasil sintesis nanopartikel perak terkecil diperoleh pada pH 9 dan waktu sintesis 4 menit. Kata kunci: Ekstrak Daun Teh Hijau, Nanopartikel Perak, Iradiasi Microwave ABSTRACT Research has been carried out on the synthesis of silver nanoparticles using a bioreductor of green tea leaf extract (Camellia Sinensis) by irradiation microwave.This research aimed to determine the effect of synthesis time and pH stabilizer on the synthesis of silver nanoparticles of green tea leaf extract by microwave irradiation and it’s characterization. The 3 mM AgNO3 solution was reduced using green tea leaf extract and microwave irradiated in a variation of the synthesis time 1-5 minutes. The determining optimum of sythesis time was done by analysis of UV-Vis spectrum for every minutes. Nanoparticles with a synthesis time of 4 minutes, the stabilizer of silver nanoparticles used citric acid and NaOH with a pH of 6-9. Characterization of nanoparticles using SEM-EDS instrument (Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy) and PSA (Particle Size Analyzer). The results showed that the optimal synthesis time was 4 minutes. The morphology of silver nanopaticles characterized using SEM produced tends to aggregate. The tendency of nanoparticles to aggregate causes size or diameter of nanoparticles was random. The size and distribution of size silver nanoparticles characterized using PSA were produced at pH 6 between 31.01 - 402.44 nm with an average size of 91 nm, pH 7 between 35.03 - 740,899 nm with an average size amounting to 106.3 nm, pH 8 between 39.58 - 193.48 nm with an average size of 71.7, and pH 9 between 35.03 - 171.25 nm with an average size of 64.4 nm. It was concluded that the synthesis of the smallest silver nanoparticles was obtained at pH 9 and synthesis time of 4 minutes. Keywords: Green Tea Leaf Extract, Silver Nanoparticles, Microwave Irradiation


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