Study of Corrosion Protection of Concrete in Sewage Systems with Magnesium Hydroxide Coatings

The purpose of the present work was to study the corrosion protection that relatively low-cost magnesium hydroxide coatings offer to concrete by stabilizing the surface pH. To facilitate the material’s adhesive ability, methyl-cellulose and carboxymethyl-cellulose were used as environmentally friendly additives in three different concentrations, 1, 0.4 and 0.1 wt.% of solids, respectively. The coatings were applied on the surface of concrete blocks, in two different coating thicknesses. A sulfuric acid solution was used to simulate the biologically produced acid in sewer pipes. Sulfuric acid was sprayed on the specimens, while the total amount of acid sprayed was calculated, in order to correspond to a specific reaction’s stoichiometry daily. The surface pH of coated specimens was monitored daily with a surface pH meter. The gypsum production was studied with X-ray diffraction, to evaluate the coatings’ protection. The experimental time period that coatings were consumed was compared with the theoretically consumption time.

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Comparison of Different Magnesium Hydroxide Coatings Applied on Concrete Substrates (Sewer Pipes) for Protection against Bio-Corrosion

Water ◽

10.3390/w13091227 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1227

Author(s):

Domna Merachtsaki ◽

Eirini-Chrysanthi Tsardaka ◽

Eleftherios K. Anastasiou ◽

Haris Yiannoulakis ◽

Anastasios Zouboulis

Keyword(s):

Sulfuric Acid ◽

Magnesium Hydroxide ◽

Concrete Surface ◽

Sem Analysis ◽

Acid Attack ◽

Sewer Pipes ◽

Surface Ph ◽

Adhesion Ability ◽

Coating Mass ◽

Surface Morphologies

Several coatings and linings have been examined and used for the protection of sewer concrete pipes, against mainly biogenic-provoked corrosion due to the production of bio-sulfuric acid, leading to the degradation of the pipes’ structure and eventually, to their collapse and need for costly replacement. This study aimed to examine the potential differences between five different magnesium hydroxide coatings, prepared from powders presenting different purity, surface area and pore size distribution, when applied as corrosion protection agents. These coatings were tested by using accelerated sulfuric acid spraying tests, both in dry and wet coating conditions. The coating adhesion ability and their microstructure were examined by the application of pull-off measurements and of SEM analysis, respectively and were found to present certain differences, regarding the adhesion ability and the surface morphologies. During the acid spraying procedure, the surface pH and the mass change of coated concrete specimens were recorded daily. The surface pH was reduced towards acidic values and the mass reduction approached almost −20% in comparison with the initial coating mass for certain cases. Additionally, the hardness and roughness of concrete surface under the coating layer (i.e., the interface between the coating and the surface) after four days of acid spraying, exhibited much smaller changes (due to protection) in contrast to the uncoated concrete specimens (used as blank/comparison experiments), which were found to be highly affected/corroded. The formation of concrete corrosion and coating by-products, as noticed after the respective chemical reactions, was recorded by X-ray diffraction (XRD) measurements and the respective quantification of obtained results. In all the coated specimens only very small amounts of the major by-product (gypsum) was observed, indicating that the concrete surface was sufficiently protected from sulfuric acid attack.

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Properties and Performance of Novel Mg(OH)2-Based Coatings for Corrosion Mitigation in Concrete Sewer Pipes

Materials ◽

10.3390/ma13225291 ◽

2020 ◽

Vol 13 (22) ◽

pp. 5291

Author(s):

Domna Merachtsaki ◽

Georgios Fytianos ◽

Efthimios Papastergiadis ◽

Petros Samaras ◽

Haris Yiannoulakis ◽

...

Keyword(s):

Sulfuric Acid ◽

Magnesium Hydroxide ◽

Low Cost ◽

Concrete Surface ◽

Initial Surface ◽

Acid Attack ◽

Sewer Pipes ◽

Surface Samples ◽

Protected Surface ◽

And Performance

The biological activity occurring in urban sewerage systems usually leads to the (biogenic) corrosion of pipe infrastructure. Anti-corrosion coating technology was developed in an effort to protect sewer pipes from degradation. This study evaluates a new class of relatively low-cost magnesium hydroxide-based coatings, regarding their ability to adhere efficiently onto the concrete surface, and offer efficient corrosion protection. Six magnesium hydroxide-based coatings were prepared with the addition of two different types of cellulose, used as adhesion additives, and these were applied on concrete specimens. Pull-off measurements showed that the addition of higher amounts of cellulose could improve the coating adhesion onto the concrete surface. An accelerated sulfuric acid spraying test was used to evaluate the consumption time of the applied coatings and their efficiency in maintaining over time slightly alkaline pH values (above 8) on the coated/protected surfaces. At the end of spraying test, a mineralogical analysis of surface samples was performed, indicating that the formation of corrosion by-products (mainly gypsum) was increased when the added amount of cellulose was lower. Hardness and roughness measurements were also conducted on the concrete surfaces, revealing that the coatings helped the concrete surface to preserve its initial surface properties, in comparison to the uncoated specimens. A SEM/microstructure analysis showed that aggregates were formed (possibly consisting of Mg(OH)2), affecting the reactivity of the protected surface against sulfuric acid attack.

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Evaluation of the Protection Ability of a Magnesium Hydroxide Coating against the Bio-Corrosion of Concrete Sewer Pipes, by Using Short and Long Duration Accelerated Acid Spraying Tests

Materials ◽

10.3390/ma14174897 ◽

2021 ◽

Vol 14 (17) ◽

pp. 4897

Author(s):

Domna Merachtsaki ◽

Eirini-Chrysanthi Tsardaka ◽

Eleftherios Anastasiou ◽

Anastasios Zouboulis

Keyword(s):

Sulfuric Acid ◽

Magnesium Hydroxide ◽

Xrd Analysis ◽

Sem Analysis ◽

Health Issues ◽

X Ray Diffraction ◽

Corrosion Properties ◽

Sewer Pipes ◽

Adhesion Ability ◽

Long Duration

The Microbiologically Induced Corrosion (MIC) of concrete sewer pipes is a commonly known problem that can lead to the destruction of the system, creating multiple public health issues and the need for costly repair investments. The present study focuses on the development of a magnesium hydroxide coating, with optimized properties to protect concrete against MIC. The anti-corrosion properties of the respective coating were evaluated by using short and long duration accelerated sulfuric acid spraying tests. The coating presented satisfying adhesion ability, based on pull-off and Scanning Electron Microscopy (SEM) analysis measurements. The surface pH of the coated concrete was maintained at the alkaline region (i.e., >8.0) throughout the duration of all acid spraying tests. The consumption of the coating, due to the reaction (neutralization) with sulfuric acid, was confirmed by the respective mass and thickness measurements. The protection ability of this coating was also evaluated by recording the formation of gypsum (i.e., the main corrosion product of concrete) during the performed tests, by X-ray Diffraction (XRD) analysis and by the Attenuated Total Reflectance (ATR) measurements. Finally, a long duration acid spraying test was additionally used to evaluate the behavior of the coating, simulating better the conditions existing in a real sewer pipe, and the obtained results showed that this coating is capable of offering prolonged protection to the concrete substrate.

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In Situ Synthesis of B4C / TiB2 Composites from Low Cost Sugar Based Precursor

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.297-301.52 ◽

2010 ◽

Vol 297-301 ◽

pp. 52-56 ◽

Cited By ~ 4

Author(s):

E. Çakır ◽

Celaletdin Ergun ◽

Filiz Çinar Şahin ◽

İ. Erden

Keyword(s):

Sulfuric Acid ◽

Low Cost ◽

X Ray Diffraction ◽

X Ray ◽

Heat Treated ◽

Precursor Material

In the present study, a method based on sulfuric acid dehydration of sugar was developed to synthesis a precursor material, which can yield B4C/ TiB2 composites at much lower temperatures compared to traditional carbothermal methods. The precursor material for pure B4C and B4C / TiB2 composites were heat treated at 1650oC under Ar and Ar+H2 atmosphere. Then the samples were characterized by X-ray diffraction (XRD) and crystallized B4C and B4C / TiB2 composites can be obtained at 1650oC

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High Quality, Low Cost Continuous Poly-GaN Film on Si and Glass Substrates Produced by Spin Coating

MRS Proceedings ◽

10.1557/proc-831-e8.2 ◽

2004 ◽

Vol 831 ◽

Author(s):

Huaqiang Wu ◽

Athanasios Bourlinos ◽

Emmanuel P. Giannelis ◽

Michael G. Spencer

Keyword(s):

Spin Coating ◽

Low Cost ◽

Methyl Cellulose ◽

Colloidal Dispersions ◽

X Ray Diffraction ◽

High Quality ◽

Light Emitting ◽

Light Emitting Devices ◽

Glass Substrates ◽

Strong Luminescence

ABSTRACTPolycrystalline GaN layers have been produced on generic substrates via spin coating. Based on X-ray diffraction and SEM analyses, the GaN particles appear to be highly oriented on the surface. Strong luminescence from these layers has been demonstrated by cathodoluminescence. The source material was high purity, high quality GaN powder produced in our laboratory. Methyl cellulose was successfully used to disaggregate GaN particles in the dispersion. The colloidal dispersions were spun onto different substrates: Si, sapphire and glass. The dispersant was removed by annealing the sample at 500°C. The layer thickness was controlled by varying the number of spin coatings. Applications for spindeposited GaN layers include the fields of light emitting devices and random lasers.

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Study of Magnesium Hydroxide Protective Coating against Corrosion, Applied on Poly(methyl methacrylate) Plates, By Using the Sulfuric Acid Attack Acceleration Test

Materials Proceedings ◽

10.3390/materproc2021005004 ◽

2021 ◽

Vol 5 (1) ◽

pp. 4

Author(s):

Domna Merachtsaki ◽

Eirini-Chrysanthi Tsardaka ◽

Eleftherios Anastasiou ◽

Anastasios Zouboulis

Keyword(s):

Sulfuric Acid ◽

Methyl Methacrylate ◽

Magnesium Hydroxide ◽

Concrete Surface ◽

X Ray Diffraction ◽

Acid Attack ◽

Poly Methyl Methacrylate ◽

Concrete Pipes ◽

Custom Made ◽

Microbiologically Induced Corrosion

Microbiologically induced corrosion (MIC) leads to the degradation/deterioration of concrete pipes, due to the formation of gypsum. Magnesium hydroxide powders may protect the concrete surface by maintaining alkaline pH values at the surface, or by neutralizing the biogenic produced sulfuric acid. An accelerated sulfuric acid spraying test in a custom-made spraying chamber used to examine the consumption of magnesium hydroxide coating, which was applied on poly (methyl methacrylate) plates, instead of applying it on concrete substrates. In that way, only the magnesium hydroxide coating can interact with the acid and can be examined separately. Surface pH measurements and the mass changes were daily conducted, during the four-day accelerated spraying test. The mineralogical phases of the surface were determined by using X-ray Diffraction (XRD) measurements.

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Preparation of Zn-MOFs by microwave-assisted ball milling for removal of tetracycline hydrochloride and Congo red from wastewater

Green Processing and Synthesis ◽

10.1515/gps-2021-0020 ◽

2021 ◽

Vol 10 (1) ◽

pp. 125-133

Author(s):

Qinhui Ren ◽

Fuhua Wei ◽

Hongliang Chen ◽

Ding Chen ◽

Bo Ding

Keyword(s):

Ball Milling ◽

Congo Red ◽

Low Cost ◽

Metal Organic Framework ◽

Tetracycline Hydrochloride ◽

Infrared Spectrometry ◽

X Ray Diffraction ◽

Wastewater Purification ◽

Microwave Assisted ◽

Metal Organic

Abstract In this study, we prepared Zn-MOFs as an ordinary, low-cost, and efficiency method taking advantage of zinc(ii) acetate monohydrate and 1,3,5-benzenetricarboxylic acid in microwave-assisted ball milling. The Zn-MOFs were measured via scanning electron microscopy, infrared spectrometry, X-ray diffraction, and thermogravimetry. We explored its use as a photocatalyst for the degradation of tetracycline hydrochloride and Congo red from aqueous solutions. The results demonstrate that the kinetic model was appropriate for the removal of organic pollutants. In general, it is feasible, inexpensive, and effective to use metal organic framework (MOF) to treat waste liquid. Therefore, our findings indicate that Zn-MOFs have broad application vista in wastewater purification.

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Multidimensional Ln-Aminophthalate Photoluminescent Coordination Polymers

Materials ◽

10.3390/ma14071786 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1786

Author(s):

Carla Queirós ◽

Chen Sun ◽

Ana M. G. Silva ◽

Baltazar de Castro ◽

Juan Cabanillas-Gonzalez ◽

...

Keyword(s):

Water Content ◽

Coordination Polymers ◽

Metal Ion ◽

Low Cost ◽

Microwave Assisted Synthesis ◽

X Ray Diffraction ◽

X Ray ◽

Wide Range ◽

Ft Ir ◽

Ft Ir Spectroscopy

The development of straightforward reproducible methods for the preparation of new photoluminescent coordination polymers (CPs) is an important goal in luminescence and chemical sensing fields. Isophthalic acid derivatives have been reported for a wide range of applications, and in addition to their relatively low cost, have encouraged its use in the preparation of novel lanthanide-based coordination polymers (LnCPs). Considering that the photoluminescent properties of these CPs are highly dependent on the existence of water molecules in the crystal structure, our research efforts are now focused on the preparation of CP with the lowest water content possible, while considering a green chemistry approach. One- and two-dimensional (1D and 2D) LnCPs were prepared from 5-aminoisophthalic acid and Sm3+/Tb3+ using hydrothermal and/or microwave-assisted synthesis. The unprecedented LnCPs were characterized by single-crystal X-ray diffraction (SCRXD), powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM), and their photoluminescence (PL) properties were studied in the solid state, at room temperature, using the CPs as powders and encapsulated in poly(methyl methacrylate (PMMA) films, envisaging the potential preparation of devices for sensing. The materials revealed interesting PL properties that depend on the dimensionality, metal ion, co-ligand used and water content.

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Flame Retardant Polyamide 6 Composites Using NMH or NMH/MCA/APP

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.1208 ◽

2011 ◽

Vol 189-193 ◽

pp. 1208-1211 ◽

Cited By ~ 1

Author(s):

Yan Shen ◽

Shao Guo Wen ◽

Ji Hu Wang ◽

Hong Bo Liu ◽

Hai Liang Qi ◽

...

Keyword(s):

Flame Retardant ◽

Magnesium Hydroxide ◽

Flame Retardants ◽

Polyamide 6 ◽

X Ray Diffraction ◽

Upward Trend ◽

Orthorhombic Crystal ◽

Orthorhombic Crystal Structure ◽

Orthogonal Experiments ◽

Nitrogen Phosphorus

In this paper, flame retardant Polyamide 6 (PA6) composites were prepared by nano-magnesium hydroxide (NMH) or its composites with melamine cyanurate(MCA) and ammonium polyphosphate(APP). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to analyze the structure of nano-magnesium hydroxide. The properties including tensile properties, molten index (MFI), rockwell hardness and density of flame retardant PA6 were analyzed. Orthogonal experiments were used to study flame retardancy of PA6 with NMH, MCA and APP. The results showed NMH had hexagonal orthorhombic crystal structure with size of 300×200×100nm. Density of polyamide 6 showed an upward trend when the content of NMH was increasing, the mechanical properties and hardness changed little while processing performance serious declined. The flame retardance of nitrogen-phosphorus -inorganic flame retardants was not desirable.

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Sensing Performance of Al and Sn Doped ZnO for Hydrogen Detection

Proceedings ◽

10.3390/proceedings2019014039 ◽

2019 ◽

Vol 14 (1) ◽

pp. 39

Author(s):

Zahira. El khalidi ◽

Maryam Siadat ◽

Elisabetta. Comini ◽

Salah. Fadili ◽

Philippe. Thevenin

Keyword(s):

Zinc Oxide ◽

Chemical Sensor ◽

Low Cost ◽

Zinc Powder ◽

Health Condition ◽

Vibration Modes ◽

X Ray Diffraction ◽

Grain Sizes ◽

Pure Oxide ◽

Doped Zno

Chemical gas sensors were studied long ago and nowadays, for the advantageous role they provide to the environment, health condition monitoring and protection. The recent studies focus on the semiconductors sensing abilities, especially of non toxic and low cost compounds. The present work describes the steps to elaborate and perform a chemical sensor using intrinsic and doped semiconductor zinc oxide. First, we synthesized pure oxide using zinc powder, then, two other samples were established where we introduced the same doping percentage of Al and Sn respectively. Using low cost spray pyrolysis, and respecting the same conditions of preparation. The obtained samples were then characterized by X Ray Diffraction (XRD) that revealed the hexagonal wurzite structure and higher crystallite density towards the direction (002), besides the appearance of the vibration modes related to zinc oxide, confirmed by Raman spectroscopy. SEM spectroscopy showed that the surface morphology is ideal for oxidizing/reduction reactions, due to the porous structure and the low grain sizes, especially observed for the sample Sn doped ZnO. The gas testing confirms these predictions showing that the highest response is related to Sn doped ZnO compared to ZnO and followed by Al doped ZnO. The films exhibited responses towards: CO, acetone, methanol, H2, ammonia and NO2. The concentrations were varied from 10 to 500 ppm and the working temperatures from 250 to 500°C, the optimal working temperatures were 350 and 400 °C. Sn doped ZnO showed a high response towards H2 gas target, with a sensitivity reaching 200 at 500 ppm, for 400 °C.

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