Arsenic removal by iron hydroxides, produced by enhanced corrosion of iron

2002 ◽  
Vol 2 (2) ◽  
pp. 237-245 ◽  
Author(s):  
K. Karschunke ◽  
M. Jekel
Keyword(s):  
Drinking Water ◽  
Corrosion Rate ◽  
Arsenic Removal ◽  
Galvanic Corrosion ◽  
Iron Hydroxides ◽  
Copper Release ◽  
Iron Copper ◽  
Oxygenated Water ◽  
Fine Iron ◽  
Corrosion Of Iron

Results of lab-scale experiments for arsenic removal from drinking water are presented. Arsenate(V)-ions were adsorbed on ferric hydroxides which were formed in-situ by corrosion of elemental iron in oxygenated water. Natural corrosion of fine iron wool was suitable to remove effectively high but realistic arsenic concentrations of 500 μg/L from drinking water. As the corrosion rate decreased significantly in time, two different methods to enhance the corrosion were tested and evaluated: galvanic corrosion using iron-copper contact elements and the application of an external voltage. The iron-copper contact elements showed promising results (a high and stable corrosion rate) but were bearing the risk of copper release when the contact broke down. The application of voltage led to an enhanced release of iron-ions but was coupled with a cathodic formation of hydrogen from water. The generation of hydrogen is a very undesirable effect for any practical application. Irrespective of the mode of corrosion, a post-treatment step (sand filtration) was required to remove the arsenic loaded rust particles from the effluent. In the final effluent, drinking water quality was reached by all the methods.

scholarly journals Corrosion Study of Iron and Copper Metals and Brass Alloy in Different Medium

2011 ◽  
Vol 8 (s1) ◽  
pp. S344-S348 ◽  
Author(s):  
Memon Samina ◽  
Abdul Karim ◽  
A. Venkatachalam
Keyword(s):  
Corrosion Rate ◽  
Brass Alloy ◽  
Corrosion Study ◽  
Iron Copper ◽  
Corrosion Of Iron

The corrosion of iron, copper and brass alloy has been investigated in different mediumi.e. HNO3, H3PO4, H2SO4, HCl, CH3COOH. The study reveals that corrosion rate increases in the order iron > copper > brass and for the medium the corrosion follows the order HNO3> H3PO4> H2SO4> HCl > CH3COOH. The rate of corrosion increases with increasing concentration of acid and with increase in time.

Effects of Velocity on Corrosion

CORROSION ◽  
1960 ◽  
Vol 16 (2) ◽  
pp. 86t-92t ◽  
Author(s):  
H. R. COPSON
Keyword(s):  
Corrosion Rate ◽  
Copper Alloy ◽  
Iron Copper ◽  
Erosion Corrosion ◽  
Velocity Effect ◽  
Corrosion Of Iron

Abstract Discusses effects of velocity of fluids on corrosion rate of metals. Explains relation between corrosion rate factors and velocity and velocity effect on corrosion of iron and other metals. Also discusses galvanic effects produced by changes in velocity. Includes discussion of erosion corrosion of iron, copper alloy and other alloys plus explanation of cavitation corrosion. 3.5.11

Copper corrosion control in the Netherlands

2001 ◽  
Vol 1 (3) ◽  
pp. 75-82 ◽  
Author(s):  
P.G.G. Slaats ◽  
H. Brink ◽  
T.J.J. van der Hoven
Keyword(s):  
Drinking Water ◽  
The Netherlands ◽  
Treatment Techniques ◽  
Copper Pipe ◽  
Copper Release ◽  
Average Intake ◽  
Split Treatment ◽  
New Treatment ◽  
Monitoring Protocols ◽  
Copper Solubility

Copper is the most commonly used material for pipes in domestic installations in the Netherlands. Depending on the composition of the water the copper pipes can add a significant amount of copper to drinking water. In the new European Drinking Water Directive (98/83/EC) the parametric value for copper in drinking water is decreased from 3 to 2 mg/l. The new directive also stipulates that copper levels should be determined on the basis of a sample ‘taken at the consumers' tap’ representative of the weekly average intake by humans. Harmonisation of monitoring protocols for copper in the European member states is necessary. In the Netherlands about 45% of the drinking water is already softened or de-acidified in order to decrease copper concentrations in drinking water. In the Netherlands two new treatment techniques have been studied for their impact on copper release; these are Reverse Osmosis (RO) and the addition of inhibitors. Copper pipe rig tests have shown that RO treatment decreases copper release. Split treatment of water with RO reduces copper solubility of drinking water through a decrease in both total inorganic carbon (TIC) and sulphate level. Remarkable was the relatively small decrease in copper release after split treatment with RO, compared to previous experiences in the Netherlands, suggesting an effect of natural organic matter. A new promising technique in the Netherlands is the addition of the inhibitor carbonate-activated silicate. At the test sites, the reduction in copper solubility due to the use of carbonate-activated silicate was 15 to 35%.

scholarly journals Corrosion resistance of metalized layers on steel parts in ventilation mill

10.30544/340 ◽  
2018 ◽  
Vol 24 (2) ◽  
pp. 123-132
Author(s):  
Bore V. Jegdic ◽  
Bojana M. Radojković ◽  
Biljana M. Bobić ◽  
Marija M. Krmar ◽  
Slavica Ristić
Keyword(s):  
Corrosion Rate ◽  
Base Metal ◽  
Galvanic Corrosion ◽  
Thermal Power ◽  
Electrochemical Techniques ◽  
General Corrosion ◽  
Hvof Process ◽  
The Difference ◽  
Local Dissolution ◽  
Oxygen Fuel

Corrosion behavior of metalized layers, obtained by Plasma Transferred Arc (PTA) process and by High-Velocity Oxygen Fuel (HVOF) process with the purpose to improve the wear resistance of vital parts of ventilation mill in a thermal power plant, has been tested. The test is performed using three electrochemical techniques, in a solution containing chloride and sulfate ions. It is shown that the steel surface (base metal) dissolves uniformly, without pitting or other forms of local dissolution. Morphology of metalized layers surface indicates that dissolution is non-uniform, but it still can be considered as general corrosion. The corrosion rate of base metal and metalized layer obtained by PTA process is rather low, while the corrosion rate of the metalized layer obtained by HVOF process is much higher. Also, the difference in corrosion potentials between the base metal and the HVOF layer is pretty high but slightly less than maximum allowed difference (prescribed by the standard), to avoid excessive galvanic corrosion. The values of corrosion rate obtained by different electrochemical techniques are in excellent agreement.

Strain Enhanced Corrosion in the Iron-Caustic System

CORROSION ◽  
1976 ◽  
Vol 32 (9) ◽  
pp. 353-357 ◽  
Author(s):  
RONALD B. DIEGLE ◽  
DAVID A. VERMILYEA
Keyword(s):  
Steady State ◽  
Corrosion Rate ◽  
Strain Rate ◽  
Electrolyte Concentration ◽  
Applied Strain ◽  
Crack Advance ◽  
Film Rupture ◽  
Applied Strain Rate ◽  
Corrosion Of Iron ◽  
Kinetics Of

Abstract Straining electrode experiments were performed to investigate the nature of strain enhanced corrosion of iron in caustic electrolyte. The strain enhanced corrosion rate was generally linearly dependent on applied strain rate, and its potential dependence paralleled that of steady-state polarization behavior on non-straining electrodes. Data was presented as ratios, in which is the corrosion rate in cm/s and is the corresponding strain rate. This ratio, which was shown in a previously published theory to be numerically equal to the crack advance per film rupture event during film rupture SCC, depended on electrochemical variables such as electrolyte concentration and temperature in a manner similar to the kinetics of caustic cracking. Conditions which are known to be marginal in producing caustic cracking resulted in values for of about 10−7 cm, in excellent agreement with a previously developed theory. It was concluded that strain enhanced corrosion in this system results from repetitive film rupture and repair during straining.

Development of a low-waste technology for arsenic removal from drinking water

2003 ◽  
pp. 491-501 ◽  
Author(s):  
József Hlavay ◽  
Klára Polyák ◽  
János Molnár ◽  
Kornél Gruber ◽  
Pál Medgyesi ◽  
...  
Keyword(s):  
Drinking Water ◽  
Arsenic Removal

scholarly journals Nanofiltration for Arsenic Removal: Challenges, Recent Developments, and Perspectives

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1323 ◽  
Author(s):  
TA Siddique ◽  
Naba K. Dutta ◽  
Namita Roy Choudhury
Keyword(s):  
Drinking Water ◽  
Arsenic Removal ◽  
Environmental Concern ◽  
Low Cost ◽  
Inorganic Arsenic ◽  
Water Security ◽  
Polymer Nanocomposite ◽  
Life Forms ◽  
Current Status ◽  
The Status

Arsenic (As) removal is of major significance because inorganic arsenic is highly toxic to all life forms, is a confirmed carcinogen, and is of significant environmental concern. As contamination in drinking water alone threatens more than 150 million people all over the world. Therefore, several conventional methods such as oxidation, coagulation, adsorption, etc., have been implemented for As removal, but due to their cost-maintenance limitations; there is a drive for advanced, low cost nanofiltration membrane-based technology. Thus, in order to address the increasing demand of fresh and drinking water, this review focuses on advanced nanofiltration (NF) strategy for As removal to safeguard water security. The review concentrates on different types of NF membranes, membrane fabrication processes, and their mechanism and efficiency of performance for removing As from contaminated water. The article provides an overview of the current status of polymer-, polymer composite-, and polymer nanocomposite-based NF membranes, to assess the status of nanomaterial-facilitated NF membranes and to incite progress in this area. Finally, future perspectives and future trends are highlighted.

Orthophosphate removal from aqueous solutions using drinking-water treatment sludge

2013 ◽  
Vol 68 (8) ◽  
pp. 1757-1762 ◽  
Author(s):  
Krzysztof Piaskowski
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Low Cost ◽  
Drinking Water Treatment ◽  
Cost Effective ◽  
Underground Water ◽  
Iron Hydroxides ◽  
Water Treatment Sludge ◽  
Main Component ◽  
Static Conditions

Drinking-water treatment sludge (DWTS) is a by-product generated during the production of drinking water where iron hydroxides are the main component of the sludge. The aim of the study presented here was to determine the effectiveness of using ferric sludge from two underground water treatment stations to remove orthophosphates from a model solution. The analyses were performed in static conditions. The sludge was dosed in a dry and suspended form. Using sludge dried at room temperature and preparing the suspension again proved to be much less effective in orthophosphate removal than using a suspension brought directly from the station. An increase in process effectiveness with a decreasing pH was observed for all the analysed sludge. Due to the low cost and high capability, DWTS has the potential to be utilised for cost-effective removal of phosphate from wastewater.

Sign in / Sign up

Export Citation Format

Share Document