scholarly journals Chemical aspects of the process of concrete cracks elimination with the help of bacteria

2018 ◽  
Vol 5 (3) ◽  
Author(s):  
Vladimir Erofeev ◽  
Al-Dulaimi Salman Dawood Salman ◽  
Valery Fomichev
Keyword(s):  
Calcium Carbonate ◽  
Ph Value ◽  
Chemical Deposition ◽  
Self Healing ◽  
Promising Alternative ◽  
Carbon And Nitrogen ◽  
Natural Minerals ◽  
Urease Enzyme ◽  
Crystallization Center ◽  
Ca Ions

The article describes the chemical processes of biogenesis of calcium carbonate for self-healing of concrete, taking into account four main factors: the concentration of calcium, the concentration of soluble inorganic carbon, the pH value, the presence of the crystallization center. A number of bacteria that can be found in soil, sand and natural minerals have the ability to release calcium carbonate, both in natural and laboratory conditions. In the laboratory, calcium lactate (CaC6H10O6) was used as a starting material for the formation of calcium carbonate. In addition, urea necessary for bacteria as a source of urease enzyme and yeast extract as a source of carbon and nitrogen were added. The resulting pH was brought to 9 to avoid possible chemical deposition of calcium carbonate. To improve the production technology of biological concrete, specially selected bacteria of the genus Bacillus with a combination of nutrients were used to create a reducing agent in concrete. With the help of such self-healing concrete by means of bacteria, cracks more than 100 µm wide can be compacted. With this approach, the bacteria in the alkaline medium convert CO2 into carbonate ions, which then interact with the Ca ions from the concrete matrix. This leads to the formation of calcium carbonate crystals. In addition, CO2 directly reacts with the calcium hydroxide matrix, which leads to the formation of calcite precipitate. The appearance of calcium carbonate crystals of large size with the participation of bacteria incorporated into the self-healing concrete provides an excellent ability to self-healing compared to traditional or developed environmentally unsafe self-healing cement materials. That is why this area of research is a promising alternative to environmentally hazardous methods of repair using cement.

Optimization of HCO3- Production Reflect to CaСo3 Precipitation for Self-Healing by Bacillus sphaericus

2015 ◽  
Vol 802 ◽  
pp. 549-554 ◽  
Author(s):  
Norfaniza Mokhtar ◽  
Zhameir Shafiq Mohd Ilias ◽  
Husnul Azan Tajarudin ◽  
Megat Azmi Megat Johari
Keyword(s):  
Calcium Carbonate ◽  
Bacillus Sphaericus ◽  
Urea Concentration ◽  
Bacterial Degradation ◽  
Self Healing ◽  
Precipitate Calcium Carbonate ◽  
Urease Enzyme ◽  
Experimental Works ◽  
Metabolic Activities ◽  
Good Environment

Bacteria are able to perform metabolic activities which promote the precipitation of calcium carbonate in the form of calcite. Bacillus Sphaericus was used in this study, which is an ureolytic bacteria that can precipitate calcium carbonate in its environment by the decomposition of urea into ammonium and carbonate. The bacterial degradation of urea basically increases the pH and promotes the microbial deposition of carbonate as calcium carbonate. In this research, the capability of bacteria to influence the formation of HCO3- by the production of urease enzyme was investigated. Results of growth rate and characteristics of bacteria showed that 20g/L of urea concentration was able to provide a good environment for bacteria with sufficient amount of nutrient to survive. The formation of HCO3- was parallel with NH3 production where the formation of HCO3- increased slowly as the ammonia production decreased. Urea degradation with suitable concentration of urea by 20g/L may form high HCO3- compared to 25g/L urea concentration. The results from the experimental works indicated that the optimal urea concentration was 20g/L.

scholarly journals Efficacy of Liquid Protein Hydrolysate from Chicken Feather by Proteus sp. on Chili Plant (Capsicum annum)

2020 ◽  
Vol 2 (1) ◽  
pp. 43
Keyword(s):  
Antioxidant Activity ◽  
Ph Value ◽  
Protein Hydrolysate ◽  
Nitrogen Sources ◽  
Growth Effect ◽  
Poultry Waste ◽  
Carbon And Nitrogen ◽  
Capsicum Annum ◽  
Antibacterial And Antioxidant Activity ◽  
Test Plants

Huge amounts of feathers are discarded as wastage, and it has always been environmentally concerned as they are difficult to destroy. Feather establishes over 90% protein, which gives it a rigid structure. Biotechnological techniques can help to degrade the feathers and use as biofertilizer. The best strategy is by utilizing keratinase producing keratinolytic microorganisms from the poultry waste to deteriorate the feathers. The poultry sample was collected at the local poultry farm. Using skimmed milk agar, enriched proteolytic bacteria were isolated, and the colony morphology assessed. The isolated bacteria were assessed for keratinolytic ability by using carbon and nitrogen sources. Liquid protein hydrolysate (LPH) was prepared and added as fertilizer to determine the growth effect on Capsicum annum. The antibacterial and antioxidant activity was assessed. The isolated Proteus sp. from the poultry waste has the ability to disintegrate the feathers completely on the 10th day. The enzymatic activity from Proteus sp. was observed increased with the presence of fructose (1.435 U/mL) and yeast extract (2.045 U/mL). The optimum temperature was at 40 °C (0.664 U/mL), pH value 7 (0.871 U/mL), and feather concentration at 1.5% (1.2 U/mL). LPH promoted the growth of Capsicum annum and increased total chlorophyll content (5.7341mg/g) in test plants. The antimicrobial activity displayed that Escherichia coli is susceptible to LPH, and also increased antioxidant activity was demonstrated in the test plants. Thus, the addition of liquid protein hydrolysate exhibited that it has the capability to aid plant development.

scholarly journals Classification of brown earths based on field and laboratory properties: Problematic issues and proposition of their solution

2019 ◽  
Vol 52 (2) ◽  
pp. 225
Author(s):  
Karolina Woźnica ◽  
Agnieszka Józefowska ◽  
Justyna Sokołowska ◽  
Ryszard Mazurek ◽  
Tomasz Zaleski
Keyword(s):  
Calcium Carbonate ◽  
Main Parameter ◽  
Ph Value ◽  
Soil Classification ◽  
Base Saturation ◽  
Carbonate Content ◽  
Field Guide ◽  
Content Determination

<p class="Default">In this paper, the current problems associated with the classification of brown earths, are presented. According to the Polish Soil Classification (PSC) (1989, 2011), base saturation is the main parameter for identifying eutrophic and dystrophic brown soils. In practice, however, it is not possible to determine the base saturation value in the field. Therefore, the aim of this study was to estimate the base saturation using a regression equation and create a field guide for brown earths, based on the pH value, measured using a Hellige indicator, and the calcium carbonate content. Determination of the pH ranges enabled the classification of brown earth types in the field. These results suggest that pH can be used as a proxy for base saturation especially in the field. A change in the hierarchy of soil (sub)types is proposed for the new Polish Soil Classification.</p>

scholarly journals Bioprecipitation of calcium carbonate by Bacillus subtilis and its potential to self-healing in cement-based materials

2020 ◽  
Vol 18 (5) ◽  
Author(s):  
Héctor Ferral Pérez ◽  
Mónica Galicia García
Keyword(s):  
Bacillus Subtilis ◽  
Calcium Carbonate ◽  
Building Materials ◽  
Soil Stabilization ◽  
Amorphous Material ◽  
Crystallinity Index ◽  
Self Healing ◽  
Semi Solid ◽  
A Minor ◽  
Novel Applications

In recent years, biological mineralization has been implemented as a viable option for the elaboration of new building materials, protection and repair of concrete by self-healing, soil stabilization, carbon dioxide capture, and drug delivery. Biogenic mineralization of calcium carbonate (CaCO3) induced by bacterial metabolism has been proposed as an effective method. The objective of the present study was to characterize the bioprecipitation of CaCO3 crystals by Bacillus subtilis in a semi-solid system. The results show that CaCO3 crystals were produced by day 3 of incubation. The prevalent crystalline polymorph was calcite, and in a minor proportion, vaterite. The presence of amorphous material was also detected (amorphous CaCO3 (ACC)). Finally, the crystallinity index was 81.1%. This biogenic calcium carbonate does not decrease pH and does not yield chloride formation. Contrary, it increases pH values up to 10, which constitutes and advantage for implementations at reinforced concrete. Novel applications for biogenic calcium carbonate derived from Bacillus subtilis addressing self-healing, biocementation processes, and biorestoration of monuments are presented.  

scholarly journals Synthesis of calcium carbonate microcapsules as self-healing containers

RSC Advances ◽  
2019 ◽  
Vol 9 (41) ◽  
pp. 23666-23677 ◽  
Author(s):  
Nadeesha Maduwanthi Hettiarachchi ◽  
Rangika Thilan De Silva ◽  
M. M. M. G. Prasanga Gayanath Mantilaka ◽  
Pooria Pasbakhsh ◽  
K. M. Nalin De Silva ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Self Healing ◽  
Metal Coatings ◽  
Healing Agent

Healing agent, epoxy encapsulated calcium carbonate microcapsules were prepared using a facile method as a self-healing composite for protective metal coatings.

Preparation of Microcapsules for Self-Healing Polymers

2012 ◽  
Vol 729 ◽  
pp. 205-209
Author(s):  
Anna Czeller ◽  
Tibor Czigány
Keyword(s):  
Optical Microscopy ◽  
Ph Value ◽  
Low Ph ◽  
Wall Material ◽  
Self Healing ◽  
Reaction Conditions ◽  
Water Emulsion ◽  
Oil In Water ◽  
Oil In Water Emulsion ◽  
Polymerization Method

In this paper, melamin-formaldehyde microcapsules filled with pentaerythritol tetrakis (3-mercaptopropionate) (PETMP) or epoxy were prepared via oil-in-water emulsion polymerization method. Two different routes were chosen from literature, and applied with some changes. The effects of modification of reaction conditions on the resulting capsules were studied. It was found that too low pH value in the emulsion causes burst polymerization of the wall material, without microcapsule formation. When pH was set to 4.5 spherical microcapsules were formed. Optical microscopy was used to evaluate the microcapsules.

scholarly journals Control of the Polymorphism of Calcium Carbonate Produced by Self-Healing in the Cracked Part of Cementitious Materials

2017 ◽  
Vol 7 (6) ◽  
pp. 546 ◽  
Author(s):  
Heesup Choi ◽  
Hyeonggil Choi ◽  
Masumi Inoue ◽  
Risa Sengoku
Keyword(s):  
Calcium Carbonate ◽  
Cementitious Materials ◽  
Self Healing

scholarly journals Robust Self-Regeneratable Stiff Living Materials

2020 ◽  
Author(s):  
Avinash Manjula-Basavanna ◽  
Anna Duraj-Thatte ◽  
Neel S. Joshi
Keyword(s):  
Calcium Carbonate ◽  
Organic Solvents ◽  
Smart Materials ◽  
Building Block ◽  
Living Cells ◽  
Living Systems ◽  
Self Healing ◽  
Ambient Conditions ◽  
Microbial Cells ◽  
Living Materials

AbstractLiving systems have not only the exemplary capability to fabricate materials (e.g. wood, bone) under ambient conditions but they also consist of living cells that imbue them with properties like growth and self-regeneration. Like a seed that can grow into a sturdy living wood, we wondered: can living cells alone serve as the primary building block to fabricate stiff materials? Here we report the fabrication of stiff living materials (SLMs) produced entirely from microbial cells, without the incorporation of any structural biopolymers (e.g. cellulose, chitin, collagen) or biominerals (e.g. hydroxyapatite, calcium carbonate) that are known to impart stiffness to biological materials. Remarkably, SLMs are also lightweight, strong, resistant to organic solvents and can self-regenerate. This living materials technology can serve as a powerful biomanufacturing platform to design and develop sustainable structural materials, biosensors, self-regulators, self-healing and environment-responsive smart materials.

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