Inhibition effect of dissolved organic matter in secondary-treated municipal wastewater on corrosion of N80 carbon steel

2019 ◽  
Vol 19 (6) ◽  
pp. 1653-1660 ◽  
Author(s):  
Zhanhui Shen ◽  
Shuzhan Zhang ◽  
Xingyi Dong ◽  
Jialu Shi ◽  
Jing Fan ◽  
...  

Abstract Secondary-treated municipal wastewater (MWW) is the alternative water source in recirculating cooling water systems. Municipal wastewater treatment plant (WWTP) effluent was collected and four fractions including hydrophobic acidic (HPOA), hydrophobic alkaline (HPOB), weakly hydrophobic (WHPO) and hydrophilic (HPI) organics were isolated from the effluent by using DAX-8/XAD-4 resin. We used potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) to investigate corrosion characteristics of N80 carbon steel in the different water samples and control samples. In contrast with control samples, the corrosion rate of N80 carbon steel decreased 41%, 23%, 18% and 4% in the presence of HPOA, HPOB, WHPO and HPI, respectively. The results were further confirmed by the EIS test. In the presence of the four fractions (especially HPOA), the radius of the semicircle in the Nyquist plot was much larger than that for the control samples, which indicated that the impedance in the EIS test of the HPOA sample was much higher than that of the control sample. The dissolved organic matter (DOM) could adsorb onto the surface of the electrode and form a protective film, which could inhibit electron transfer and increase the electrochemical impedance of the electrochemical test system.

2013 ◽  
Vol 67 (11) ◽  
pp. 2412-2417 ◽  
Author(s):  
Zhanhui Shen ◽  
Hongqiang Ren ◽  
Ke Xu ◽  
Jinju Geng ◽  
Lili Ding

Secondary-treated municipal wastewater (MWW) could supply a viable alternative water resource for cooling water systems. Inorganic salts in the concentrated cooling water pose a great challenge to corrosion control chemicals. In this study, the inhibition effect of 1-hydroxy ethylidene-1,1-diphosphonic acid (HEDP), trimethylene phosphonic acid (ATMP) and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) on corrosion of carbon steel in secondary-treated MWW was investigated by the means of potentiodynamic polarization and electrochemical impedance spectroscopy. The inhibition effect increased with increasing concentration of inhibitors. The corrosion rates of carbon steel were 1.5, 0.8, 0.2 and 0.5 mm a–1 for blank, HEDP, ATMP and PBTCA samples at 50 mg L–1, respectively. The phosphorus-based chemicals could adsorb onto the surface of the carbon steel electrode, form a coat of protective film and then protect the carbon steel from corrosion in the test solution.


Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1992
Author(s):  
Luis Cáceres ◽  
Yohana Frez ◽  
Felipe Galleguillos ◽  
Alvaro Soliz ◽  
Benito Gómez-Silva ◽  
...  

The implementation of corrosion engineering control methods and techniques is crucial to extend the life of urban and industrial infrastructure assets and industrial equipment affected by natural corrosion. Then, the search of stable and environmentally friendly corrosion inhibitors is an important pending task. Here, we provide experimental evidence on the corrosion inhibitory activity of aqueous extracts of Skytanthus acutus Meyen leaf, a native plant from the Atacama Desert in northern Chile. Skytanthus extracts as a powder should be prepared at 55 °C to avoid thermal decomposition and loss of corrosion inhibitory activity. Corrosion of carbon steel AISI1020 immersed in 0.5 M NaCl was evaluated in the presence of different doses of Skytanthus extract by complementary and simultaneous linear polarization, electrochemical impedance spectroscopy, and weight-loss technique under high hydrodynamic conditions. Mixed Potential Theory was applied to confirm the electrochemical activity of the extract inhibitory capabilities. The Skytanthus extracts reached a 90% corrosion inhibitory efficiency when tested at 100 to 1200 ppm in a time span of 48 h, through an electrochemical interaction between the extract inhibitor component and the carbon steel surface. The corrosion inhibition activity observed in Skytanthus dry extracts involves a protective film formation by a mechanism that includes an iron dissolution at the expense of either oxygen reduction and/or hydrogen evolution, followed by a ferrous-ferric iron cycling, the formation of an iron complex and adsorption to the metal surface, and, finally, desorption or degradation of the protecting film. The water-soluble plant extract was subjected to HPLC-MS analyses that rendered 14 major signals, with quinic acid, protocatechuic acid, chlorogenic acid isomers, vanillic acid hexoside, and patuletin 3-methoxy-7-glucoside as the most abundant components. Then, we propose that a phenolic derivative is responsible for the corrosion inhibitory activity found in Skytanthus extracts.


2020 ◽  
Vol 1012 ◽  
pp. 390-394
Author(s):  
C. Vieira ◽  
D. Borges ◽  
D.C.S. Oliszeski ◽  
L.F.G. Larsson ◽  
E.P. Banczek

Carbon steel is one of the most commonly used alloys in industrial applications due to its physicochemical properties and low cost. However, the use of this metal material may become limited due to its vulnerability to corrosion. Thus, it is necessary to use methods that inhibit corrosion. Organic compounds with heteroatoms possess the characteristic of inhibiting corrosion by forming a protective film. The corrosion protection of SAE 1020 carbon steel, promoted by the aqueous extract of Persea pyrifolia (PP) bark, was evaluated in this work at extract concentrations of 5% and 10% v/v, in order to replace an inhibitor of synthetic origin with an ecologically benign inhibitor. Plant extracts are generally inexpensive and can be obtained through simple extraction processes. The objective of this work was to study the use of PP peel extract as a carbon steel corrosion inhibitor (SAE 1020). The electrochemical response was determined by measurements including electrochemical impedance spectroscopy (EIS) and anodic potentiodynamic polarization (PPA) in a 0.5 M sodium chloride medium. The samples were characterized by optical microscopy to evaluate the type of corrosion.


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