Effect of imposed electrical gradient on removal of toxic salt contaminants from alkali-saline low permeable soil during electrokinetic remediation

2020 ◽  
Vol 13 (14) ◽  
Author(s):  
Mohammed Mustapha Bessaim ◽  
Oznur Karaca ◽  
Hanifi Missoum ◽  
Karim Bendani ◽  
Nadia Laredj ◽  
...  
Author(s):  
S.M.P.A Koliyabandara ◽  
Chamika Siriwardhana ◽  
Sakuni M. De Silva ◽  
Janitha Walpita ◽  
Asitha T. Cooray

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2663
Author(s):  
Hyun Jun Woo ◽  
Ji Yeong Yang ◽  
Pyeongjae Lee ◽  
Jong-Bae Kim ◽  
Sa-Hyun Kim

Helicobacter pylori (H. pylori) produces urease in order to improve its settlement and growth in the human gastric epithelium. Urease inhibitors likely represent potentially powerful therapeutics for treating H. pylori; however, their instability and toxicity have proven problematic in human clinical trials. In this study, we investigate the ability of a natural compound extracted from Zingiber zerumbet Smith, zerumbone, to inhibit the urease activity of H. pylori by formation of urease dimers, trimers, or tetramers. As an oxygen atom possesses stronger electronegativity than the first carbon atom bonded to it, in the zerumbone structure, the neighboring second carbon atom shows a relatively negative charge (δ−) and the next carbon atom shows a positive charge (δ+), sequentially. Due to this electrical gradient, it is possible that H. pylori urease with its negative charges (such as thiol radicals) might bind to the β-position carbon of zerumbone. Our results show that zerumbone dimerized, trimerized, or tetramerized with both H. pylori urease A and urease B molecules, and that this formation of complex inhibited H. pylori urease activity. Although zerumbone did not affect either gene transcription or the protein expression of urease A and urease B, our study demonstrated that zerumbone could effectively dimerize with both urease molecules and caused significant functional inhibition of urease activity. In short, our findings suggest that zerumbone may be an effective H. pylori urease inhibitor that may be suitable for therapeutic use in humans.


2021 ◽  
Vol 11 (4) ◽  
pp. 1799
Author(s):  
Claudio Cameselle ◽  
Susana Gouveia ◽  
Adrian Cabo

The electrokinetic remediation of an agricultural soil contaminated with heavy metals was studied using organic acids as facilitating agents. The unenhanced electrokinetic treatment using deionized water as processing fluid did not show any significant mobilization and removal of heavy metals due to the low solubilization of metals and precipitation at high pH conditions close to the cathode. EDTA and citric acid 0.1 M were used as facilitating agents to favor the dissolution and transportation of metals. The organic acids were added to the catholyte and penetrated into the soil specimen by electromigration. EDTA formed negatively charged complexes. Citric acid formed neutral metal complexes in the soil pH conditions (pH = 2–4). Citric acid was much more effective in the dissolution and transportation out of the soil specimen of complexed metals. In order to enhance the removal of metals, the concentration of citric acid was increased up to 0.5 M, resulting in the removal of 78.7% of Cd, 78.6% of Co, 72.5% of Cu, 73.3% of Zn, 11.8% of Cr and 9.8% of Pb.


2021 ◽  
Vol 413 ◽  
pp. 125274
Author(s):  
Jamie M. Purkis ◽  
Phil E. Warwick ◽  
James Graham ◽  
Shaun D. Hemming ◽  
Andrew B. Cundy

Author(s):  
Kristine B. Pedersen ◽  
Ahmed Benamar ◽  
Mohamed T. Ammami ◽  
Florence Portet‐Koltalo ◽  
Gunvor M. Kirkelund

2000 ◽  
Vol 42 (7-8) ◽  
pp. 335-343 ◽  
Author(s):  
S. Shiba ◽  
S. Hino ◽  
Y. Hirata ◽  
T. Seno

The operational variables of electrokinetic remediation have not been cleared yet, because this method is relatively new and is an innovative technique in the aquifer remediation. In order to investigate the operational variables of the electrokinetic remediation, a mathematical model has been constructed based on the physico chemical mass transport process of heavy metals in pore water of contaminated aquifer. The transport of the heavy metals is driven not only by the hydraulic flow due to the injection of the purge water but also by the electromigration due to the application of the electric potential gradient. The electric potential between anode and cathode is the important operational variable for the electrokinetic remediation. From the numerical simulations with use of this model it is confirmed that the remediation starts from the up stream anode and gradually the heavy metal is transported to the down stream cathode and drawn out through the purge water.


Chemosphere ◽  
2014 ◽  
Vol 117 ◽  
pp. 673-678 ◽  
Author(s):  
Sivasankar Annamalai ◽  
Manikandan Santhanam ◽  
Maruthamuthu Sundaram ◽  
Marta Pazos Curras

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