scholarly journals Synthesis and Characterization of Zn–Organic Frameworks Containing Chitosan as a Low-Cost Inhibitor for Sulfuric-Acid-Induced Steel Corrosion: Practical and Computational Exploration

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 228
Author(s):  
Mohamed Gouda ◽  
Mai M. Khalaf ◽  
Kamal Shalabi ◽  
Mohammed A. Al-Omair ◽  
Hany M. Abd El-Lateef

In this work, a Zn–benzenetricarboxylic acid (Zn@H3BTC) organic framework coated with a dispersed layer of chitosan (CH/Zn@H3BTC) was synthesized using a solvothermal approach. The synthesized CH/Zn@H3BTC was characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), thermal gravimetric analysis (TGA), and Brunauer, Emmett, and Teller (BET) surface area. The microscopic observation and the analysis of the BET surface area of CH/Zn@H3BTC nanocomposites indicated that chitosan plays an important role in controlling the surface morphology and surface properties of the Zn@H3BTC. The obtained findings showed that the surface area and particle size diameter were in the range of 80 m2 g−1 and 800 nm, respectively. The corrosion protection characteristics of the CH/Zn@H3BTC composite in comparison to pristine chitosan on duplex steel in 2.0 M H2SO4 medium determined by electrochemical (E vs. time, PDP, and EIS) approaches exhibited that the entire charge transfer resistance of the chitosan- and CH/Zn@H3BTC-composite-protected films on the duplex steel substrate was comparatively large, at 252.4 and 364.8 Ω cm2 with protection capacities of 94.1% and 97.8%, respectively, in comparison to the unprotected metal surface (Rp = 20.6 Ω cm2), indicating the films efficiently protected the metal from corrosion. After dipping the uninhabited and protected systems, the surface topographies of the duplex steel were inspected by FESEM. We found the adsorption of the CH/Zn@H3BTC composite on the metal interface obeys the model of the Langmuir isotherm. The CH/Zn@H3BTC composite revealed outstanding adsorption on the metal interface as established by MD simulations and DFT calculations. Consequently, we found that the designed CH/Zn@H3BTC composite shows potential as an applicant inhibitor for steel protection.

2019 ◽  
Vol 12 (01) ◽  
pp. 1850099 ◽  
Author(s):  
Avtar Singh ◽  
Davinder Kumar ◽  
Anup Thakur ◽  
Raminder Kaur

This paper reports the effect of surface morphology on the electrochemical performance of electrodeposited manganese oxide films. These films were deposited on stainless steel substrate by chronoamperometry for different deposition time (30[Formula: see text]s, 60[Formula: see text]s, and 120[Formula: see text]s). Morphology of deposited films were studied by scanning electron microscopy and decrease in surface area was observed with variation in deposition time. Cyclic voltammetry revealed decrease in specific capacitance with decrease in surface area of films. This effect was analyzed by electrochemical impedance spectroscopy (EIS) study. Further, the EIS data were fitted with equivalent circuit of electrochemical capacitor electrode and investigating electrolyte ion interaction with electrode during charge storage process. EIS fitted data were analyzed to study the electrode characteristics such as series resistance, double layer charge storage and charge transfer resistance. The variation in these characteristics was due to change in diffusion length with increased deposited electrode material content on substrate.


2019 ◽  
Author(s):  
Charlys Bezerra ◽  
Géssica Santos ◽  
Marilia Pupo ◽  
Maria Gomes ◽  
Ronaldo Silva ◽  
...  

<p>Electrochemical oxidation processes are promising solutions for wastewater treatment due to their high efficiency, easy control and versatility. Mixed metal oxides (MMO) anodes are particularly attractive due to their low cost and specific catalytic properties. Here, we propose an innovative thermal decomposition methodology using <a>polyvinyl alcohol (PVA)</a> as a solvent to prepare Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes. Comparative anodes were prepared by conventional method employing a polymeric precursor solvent (Pechini method). The calcination temperatures studied were 300, 400 and 500 °C. The physical characterisation of all materials was performed by X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy, while electrochemical characterisation was done by cyclic voltammetry, accelerated service lifetime and electrochemical impedance spectroscopy. Both RuO<sub>2</sub> and IrO<sub>2</sub> have rutile-type structures for all anodes. Rougher and more compact surfaces are formed for the anodes prepared using PVA. Amongst temperatures studied, 300 °C using PVA as solvent is the most suitable one to produce anodes with expressive increase in voltammetric charge (250%) and accelerated service lifetime (4.3 times longer) besides reducing charge-transfer resistance (8 times lower). Moreover, the electrocatalytic activity of the anodes synthesised with PVA toward the Reactive Blue 21 dye removal in chloride medium (100 % in 30 min) is higher than that prepared by Pechini method (60 min). Additionally, the removal total organic carbon point out improved mineralisation potential of PVA anodes. Finally, this study reports a novel methodology using PVA as solvent to synthesise Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes with improved properties that can be further extended to synthesise other MMO compositions.</p>


2019 ◽  
Vol 9 (19) ◽  
pp. 3980 ◽  
Author(s):  
Saowanee Wijitkosum ◽  
Preamsuda Jiwnok

For an agricultural country such as Thailand, converting agricultural waste into biochar offers a potential solution to manage massive quantities of crop residues following harvest. This research studied the structure and chemical composition of biochar obtained from cassava rhizomes, cassava stems and corncobs, produced using a patented locally-manufactured biochar kiln using low-cost appropriate technology designed to be fabricated locally by farmers. The research found that cassava stems yielded the highest number of Brunauer-Emmett-Teller (BET) surface area in the biochar product, while chemical analysis indicated that corncobs yielded the highest amount of C (81.35%). The amount of H in the corncob biochar was also the highest (2.42%). The study also showed biochar produced by slow pyrolysis was of a high quality, with stable C and low H/C ratio. Biochar’s high BET surface area and total pore volume makes it suitable for soil amendment, contributing to reduced soil density, higher soil moisture and aeration and reduced leaching of plant nutrients from the rhizosphere. Biochar also provides a conducive habitat for beneficial soil microorganisms. The findings indicate that soil incorporation of biochar produced from agricultural crop residues can enhance food security and mitigate the contribution of the agricultural sector to climate change impacts.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Chikkur B. Pradeep Kumar ◽  
Kikkeri N. Mohana

Achyranthes aspera (AA) extracts were studied as corrosion inhibitor for mild steel (MS) in industrial water medium using mass loss and electrochemical techniques. The results of the study revealed that AA extracts inhibit MS corrosion through adsorption process following Langmuir adsorption isotherm model. The protection efficiency increased with increase in inhibitor concentration and decreased with temperature. The electrochemical impedance spectroscopy (EIS) measurements showed that the charge transfer resistance increases with increase in the concentration of AA extracts. The polarization curves obtained indicate that AA extracts act as mixed type of inhibitor. Scanning electron microscopy (SEM) was used to analyze the surface adsorbed film.


2020 ◽  
Vol 4 (1) ◽  
pp. 9-16
Author(s):  
FS Nworie ◽  
EC Oroke ◽  
II Ikelle ◽  
JS Nworu

AbstractStudies on the adsorption of Pb(II) on plantain peels biochar (PPB) was conducted. The carbonized and activated, biochar was characterized using Braunauer-Emmett-Teller (BET) surface area and x-ray diffraction crystallography (XRD). BET analysis of the PPB indicated that the pore size (cc/g) and pore surface area (m2/g) was 8.79 and 16.69 respectively. Result of the XRD evaluated through Debye-Scherrer equation, showed a nanostructure with crystallite size of 14.56 nm. Effects of initial metal ion concentration, pH, and contact time were studied in a batch reaction process. Results showed that the adsorption of lead from aqueous solution increased with an increase in pH and initial concentration. Equilibrium modeling studies suggested that the data fitted mainly to the Langmuir isotherm. Adsorption kinetic data tested using various kinetic models fitted the Weber and Morris intraparticle diffusion model implicating pore diffusion as the main rate limiting step. The sorption studies indicated the potential of plantain peel biochar as an effective, efficient and low cost adsorbent for remediating lead (II) ions contaminated environment.


Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 115
Author(s):  
Suxing Luo ◽  
Meizhi Yang ◽  
Yuanhui Wu ◽  
Jiang Li ◽  
Jun Qin ◽  
...  

Owing to its ubiquity in natural water systems and the high toxicity of its accumulation in the human body, it is essential to develop simple and low-cost electrochemical sensors for the determination of 3,3′,5,5′-tetrabromobisphenol A (TBBPA). In this work, Fe3O4–activated biochar, which is based on excess sludge, was prepared and characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and BET analysis to analyze its basic features. Subsequently, it was used to fabricate an electrochemical sensor for the detection of TBBPA. The electrochemical test results revealed that the Fe3O4–activated biochar film exhibited a larger active surface area, a lower charge transfer resistance and a higher accumulation efficiency toward TBBPA. Consequently, the peak current of TBBPA was significantly enhanced on the surface of the Fe3O4–activated biochar. The TBBPA sensing platform developed using the Fe3O4–activated biochar composite film, with relatively a lower detection limit (3.2 nM) and a wider linear range (5–1000 nM), was successfully utilized to determine TBBPA levels in water samples. In summary, the effective application of Fe3O4–activated biochar provided eco-friendly and sustainable materials for the development of a desirable high-sensitivity sensor for TBBPA detection.


2021 ◽  
Author(s):  
Zohreh Razmara

Abstract A 2D heterometallic copper(II)–sodium(I) complex based on pyridine 2,6-dicarboxylato (dipic2-) formulated as [Cu(μ-dipic)2{Na2(µ-H2O)4}]n. 2nH2O (1) has been synthesized. Thermal stability of complex 1 was studied by thermo gravimetric analysis (TGA) and differential thermal analysis (DTA). Single-crystal X-ray diffraction (SC-XRD) analysis showed that the parallelepiped colorless crystal of complex 1 crystallizes in a monoclinic system with the space group P2/c . A highly dispersed truncated octahedral catalyst formulated as Cu-Na/Al2O3 (CNM) was prepared by thermal decomposition of complex 1. Besides, the reference catalyst of Cu-Na/Al2O3 (CNR) was prepared by impregnation conventional method. The catalysts were examined by FT-IR, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area, and subjected to water-gas shift (WGS) reaction in the temperature range of 150-400 °C. The catalysts showed strong surface structure-activity dependence in WGS reaction. Improved catalytic performance during the water-gas shift reaction was observed for CNM compared to CNR due to its high dispersion, smaller particle size, and higher BET specific surface area.


Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6563
Author(s):  
Md. Mahbubur Rahman

Novel nickel nitroprusside (NNP) nanoparticles with incorporated graphene nanoplatelets (NNP/GnP) were used for the first time as a low-cost and effective counter electrode (CE) for dye-sensitized solar cells (DSSCs). NNP was synthesized at a low-temperature (25 °C) solution process with suitable purity and crystallinity with a size range from 5 to 10 nm, as confirmed by different spectroscopic and microscopic analyses. The incorporation of an optimized amount of GnP (0.2 wt%) into the NNP significantly improved the electrocatalytic behavior for the redox reaction of iodide (I-)/tri-iodide (I3-) by decreasing the charge-transfer resistance at the CE/electrolyte interface, lower than the NNP- and GnP-CEs, and comparable to the Pt-CE. The NNP/GnP nanohybrid CE when applied in DSSC exhibited a PCE of 6.13% (under one sun illumination conditions) with the Jsc, Voc, and FF of 14.22 mA/cm2, 0.628 V, and 68.68%, respectively, while the PCE of the reference Pt-CE-based DSSC was 6.37% (Jsc = 14.47 mA/cm2, Voc = 0.635 V, and FF = 69.20%). The low cost of the NNP/GnP hybrid CE with comparable photovoltaic performance to Pt-CE can be potentially exploited as a suitable replacement of Pt-CE in DSSCs.


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