scholarly journals The Application of Chitosan-Based Compounds against Metallic Corrosion

2021 ◽  
Author(s):  
Brahim El Ibrahimi ◽  
Lei Guo ◽  
Jéssica Verger Nardeli ◽  
Rachid Oukhrib

Biopolymers-based compounds were used by different manners for metal protection toward corrosion phenomena, namely via inhibiting additive and coating strategies. In the last decade, the application of these compounds or their chemically modified forms as effective replacements for toxic inorganic and organic inhibitors attracts more attention. Additionally to their intrinsic chemical stability, biodegradability, eco-friendly, low cost and renewability, biopolymers set were shown the remarkable effect to control the dissolution of several metallic materials in various corrosive environments. Among a large variety of available biopolymers, chitosan and its functionalized form, as well as its nanoparticle composites, have been reported and widely used as good anti-corrosion compounds for different metal/medium systems. In this context, the current chapter aims to shed more light on this subject.

Alloy Digest ◽  
2020 ◽  
Vol 69 (12) ◽  

Abstract Outokumpu Moda 410L/4003 is a weldable, extra low carbon, Cr-Ni, ferritic stainless steel that is best suited for mildly corrosive environments such as indoors, where the material is either not exposed to contact with water or gets regularly wiped dry, or outdoors, where some discoloration and superficial rusting are acceptable. It is a low-cost alternative to low-carbon non-alloy steels in certain applications. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-1330. Producer or source: Outokumpu Oyj.


2019 ◽  
Vol 32 (1) ◽  
pp. 73-78
Author(s):  
P. Janaki ◽  
R. Sudha ◽  
T.S. Sribharathi ◽  
P. Anitha ◽  
K. Poornima ◽  
...  

The adsorption performance of sulphuric acid treated low cost adsorbent synthesized by using Citrus limettioides peel as an effective raw material for the removal of cadmium(II) from water. The batch adsorption method was carried out to optimize some parameters like contact time, pH and adsorbent dose. The nonlinear isotherm equations were used to calculate the different isotherm constant of five isotherm models namely Freundlich, Langmuir, Dubinin-Radushkevich, Redlich-Peterson and Sips. The Langmuir monolayer adsorption capacity of chemically modified Citrus limettioides peel was found to be 287.60 mg g-1. The negative values of ΔGº and ΔHº showed that the adsorption process is spontaneous and exothermic.


2017 ◽  
Author(s):  
Marco Tadeu Gomes Vianna ◽  
Marcia Marques

The excessive release of phosphorus (P) by discharge of domestic and industrial effluents is directly associated with the eutrophication of water bodies. Therefore, an efficient removal of P from effluents is required. The method most commonly used for P removal from wastewater is chemical precipitation. However, this technique is relatively expensive and demands a proper disposal for the sludge. Therefore, the development of new materials with low cost but high P removal efficiency has been investigated. The introduction of exotic species in aquatic environments is considered a serious environmental problem in different parts of the world. Considering that, many of these species have high concentrations of carbonates in their exoskeleton composition, which is potentially useful in water treatment, particularly for P removal the use of such material as adsorbent has been tested. The present study aimed to investigate the capacity of the exoskeleton of exotic species in powder form to remove orthophosphates from water comparing the raw material (RCS), with physically modified (CSA) and chemically modified (CSC) material. To study the orthophosphates removal efficiency, a factorial design with central composite rotational design (CCRD) was applied. In order to optimize the P removal, the influence of the independent variables adsorbent/adsorbate ratio, pH and temperature was investigated with the kinetic control associate at each configuration obtained by CCRD. The P removal capacity of RCS varied from 125.0 mgP kg-1 to 1002.5 mgP kg-1; the removal capacity of CSA varied from 237.5 mgP kg-1 to 1540.0 mgP kg-1. The removal capacity of CSC varied from 5212.5 mgP kg-1 to 12672.5 mgP kg-1. Based on the preliminary results, the exoskeleton powder showed to be a potentially sustainable alternative as adsorbent material (mostly the chemically modified form CSC) useful in several applications, such as the treatment of urban and industrial wastewaters to prevent eutrophication of water bodies and population control of exotic species due to the commercial exploitation. 


Author(s):  
Anupma Gupta ◽  
Paras Chawla ◽  
Ankush Kansal ◽  
Kulbir Singh

: A defected ground antenna with dielectric reflector is designed and investigated for breast tumour diagnosis. Ultra-wide band resonance (3.1 to 10.6 GHz) is achieved by etching two slots and adding a narrow vertical strip in a patch antenna. A high dielectric constant substrate is added below the antenna, which shows remarkable effect on performance. Antenna performance is verified experimentally on an artificially fabricated breast tissue and tumour. Malignant tissue has different dielectric properties than the normal tissue, that causes deviation in the scattered antenna power. Average value of backscattered signal variation and ground penetrating radar (GPR) algorithm is used to localize the tumour of radius 4mm in breast tissue.


mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Karen N. Barnard ◽  
Brian R. Wasik ◽  
Justin R. LaClair ◽  
David W. Buchholz ◽  
Wendy S. Weichert ◽  
...  

ABSTRACT Sialic acids (Sia) are widely displayed on the surfaces of cells and tissues. Sia come in a variety of chemically modified forms, including those with acetyl modifications at the C-7, C-8, and C-9 positions. Here, we analyzed the distribution and amounts of these acetyl modifications in different human and canine cells. Since Sia or their variant forms are receptors for influenza A, B, C, and D viruses, we examined the effects of these modifications on virus infections. We confirmed that 9-O-acetyl and 7,9-O-acetyl modified Sia are widely but variably expressed across cell lines from both humans and canines. Although they were expressed on the cell surfaces of canine MDCK cell lines, they were located primarily within the Golgi compartment of human HEK-293 and A549 cells. The O-acetyl modified Sia were expressed at low levels of 1 to 2% of total Sia in these cell lines. We knocked out and overexpressed the sialate O-acetyltransferase gene (CasD1) and knocked out the sialate O-acetylesterase gene (SIAE) using CRISPR/Cas9 editing. Knocking out CasD1 removed 7,9-O- and 9-O-acetyl Sia expression, confirming previous reports. However, overexpression of CasD1 and knockout of SIAE gave only modest increases in 9-O-acetyl levels in cells and no change in 7,9-O-acetyl levels, indicating that there are complex regulations of these modifications. These modifications were essential for influenza C and D infection but had no obvious effect on influenza A and B infection. IMPORTANCE Sialic acids are key glycans that are involved in many different normal cellular functions, as well as being receptors for many pathogens. However, Sia come in diverse chemically modified forms. Here, we examined and manipulated the expression of 7,9-O- and 9-O-acetyl modified Sia on cells commonly used in influenza virus and other research by engineering the enzymes that produce or remove the acetyl groups.


2019 ◽  
Vol 48 (5) ◽  
pp. 464-471
Author(s):  
Fatma Abdelghaffar ◽  
Rehab A. Abdelghaffar ◽  
Safia A. Mahmoud ◽  
Badria M. Youssef

Purpose This paper aims to improve the adsorption capacity of sugarcane bagasse (SCB) as a low-cost, attractive and effective adsorbent for dye removal from wastewater. Design/methodology/approach SCB is a cellulosic material; it was chemically modified with compounds containing cationic groups. The adsorption efficiency of unmodified and modified SCB was investigated with anionic dyes by studying various factors that affect modified SCB and adsorption. Findings X-ray diffraction, FT-IR spectra and nitrogen content were used to confirm the effect of existence of quaternary ammonium groups on modified SCB. The morphological structure of the modified and unmodified SCB has been demonstrated using electronic scanning microscopy. Research limitations/implications The modified SCB was chemically treated by Quat 188, which is commercially available in the solution of 3-chloro-2-hydroxypropyltrimethyl ammonium chloride. Practical implications Grafting cationic function groups on the surface of sugarcane by cationization treatment enhances its adsorption efficiency for anionic dyes. Originality/value The main value of this research was indicating a clear difference in the appearance of unmodified and modified SCB surfaces. Furthermore, it can be determined that the modified SCB absorbs more of the dyes.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Marko Chigondo ◽  
Fidelis Chigondo

Traditionally, reduction of corrosion has been managed by various methods including cathodic protection, process control, reduction of the metal impurity content, and application of surface treatment techniques, as well as incorporation of suitable alloys. However, the use of corrosion inhibitors has proven to be the easiest and cheapest method for corrosion protection and prevention in acidic media. These inhibitors slow down the corrosion rate and thus prevent monetary losses due to metallic corrosion on industrial vessels, equipment, or surfaces. Inorganic and organic inhibitors are toxic and costly and thus recent focus has been turned to develop environmentally benign methods for corrosion retardation. Many researchers have recently focused on corrosion prevention methods using green inhibitors for mild steel in acidic solutions to mimic industrial processes. This paper provides an overview of types of corrosion, corrosion process, and mainly recent work done on the application of natural plant extracts as corrosion inhibitors for mild steel.


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