scholarly journals Cementation of Sand With Enzyme-Induced Carbonate Precipitation (EICP) Using Concrete-Extracted Calcium

2022 ◽  
Vol 9 ◽  
Author(s):  
Jia He ◽  
Xunyu Mao ◽  
Yundong Zhou ◽  
Qiang Tang
Keyword(s):  
Calcium Carbonate ◽  
Microscopic Analysis ◽  
Cost Effective ◽  
Carbonate Precipitation ◽  
Calcium Carbonate Precipitation ◽  
X Ray ◽  
Urease Enzyme ◽  
Crystal Type ◽  
Comparative Results ◽  
Better Than

Calcium carbonate precipitation and crystallization induced by urease enzyme to solidify soil is known as biocement technology. The uses of waste and cheap materials can make this technology more cost-effective and practical for applications. In this study, calcium ions were obtained by dissolving waste concretes in acidic liquid. Sand columns were treated by enzyme-induced carbonate precipitation (EICP) with either concrete-extracted calcium or reagent calcium for comparison. Compressive strengths, calcium carbonate contents, and microscopic analysis on the treated sand were carried out. It was found that the compressive strength of the former could reach 833 kPa in the dry state and 204 kPa in the wet state after 5 times of EICP treatment, both of which were higher than that of the latter. The calcium carbonate contents could reach 2–3% after 3–5 times of treatment. Based on the scanning electron microscope (SEM) and X-ray diffractometer (XRD) analyses, the crystal type of calcium carbonate produced in sand was calcite. The comparative results showed that the treatment effect using concrete-extracted calcium was similar or better than that using reagent calcium.

scholarly journals Role of Na-Montmorillonite on Microbially Induced Calcium Carbonate Precipitation

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6211
Author(s):  
Guowang Tang ◽  
Cangqin Jia ◽  
Guihe Wang ◽  
Peizhi Yu ◽  
Haonan Zhang
Keyword(s):  
Calcium Carbonate ◽  
Sandy Soil ◽  
Carbonate Precipitation ◽  
Soil Consolidation ◽  
X Ray Diffraction ◽  
Calcium Carbonate Precipitation ◽  
X Ray ◽  
Significant Attention ◽  
Previous Reaction

The use of additives has generated significant attention due to their extensive application in the microbially induced calcium carbonate precipitation (MICP) process. This study aims to discuss the effects of Na-montmorillonite (Na-MMT) on CaCO3 crystallization and sandy soil consolidation through the MICP process. Compared with the traditional MICP method, a larger amount of CaCO3 precipitate was obtained. Moreover, the reaction of Ca2+ ions was accelerated, and bacteria were absorbed by a small amount of Na-MMT. Meanwhile, an increase in the total cementing solution (TCS) was not conducive to the previous reaction. This problem was solved by conducting the reaction with Na-MMT. The polymorphs and morphologies of the CaCO3 precipitates were tested by using X-ray diffraction and scanning electron microscopy. Further, when Na-MMT was used, the morphology of CaCO3 changed from an individual precipitate to agglomerations of the precipitate. Compared to the experiments without Na-MMT in the MICP process, the addition of Na-MMT significantly reduced the hydraulic conductivity (HC) of sandy soil consolidated.

scholarly journals Study of the physico-chemical quality of the water of irrigation in Biougra circle along with highlighting the effectiveness of an inhibitor of calcium carbonate precipitation

2018 ◽  
Vol 7 (4) ◽  
pp. 272-285 ◽  
Author(s):  
Abdallah Hadfi ◽  
Said Ben Aazza ◽  
M'barek Belattar ◽  
Said Mohareb ◽  
Ali Driouiche
Keyword(s):  
Calcium Carbonate ◽  
Irrigation Water ◽  
Carbonate Precipitation ◽  
Chemical Quality ◽  
Calcium Carbonate Precipitation ◽  
X Ray ◽  
Water Pipes ◽  
Physico Chemical ◽  
Calcium And Magnesium

Localized irrigation is characterized by localized frequent and continuous water supply. It ensures the efficient use of water. However, this fertigation system suffers from the problem of clogging of the distributors. The present study aims to study the physico-chemical quality of the water of irrigation within the Biougra circle; analyze of the type of scale deposited in the water pipes and the highlight of the effectiveness of an inhibitor of calcium carbonate precipitation. This study was carried out at a temperature of 25°C, using the technical "LCGE". Indeed, the classification of irrigation water, according to Piper, revealed that the analyzed waters are characterized by calcium and magnesium bicarbonate facies with a slight tendency to migrate to the calcium and magnesium chloride and sulfate facies. The characterization of the scale collected in the irrigation water pipes of Biougra circle by X-ray fluorescence, X-ray diffraction and thermal analysis (ATD-ATG) made it possible to prove that the scale is mainly formed of calcium carbonate with calcite variety. The inhibition of calcium carbonate precipitation by a food inhibitor was obtained with a concentration of 0.6 mg/L.

Application of Bacteria as Self-Healing Agent for the Concrete and Microscopic Analysis of the Microbial Calcium Precipitation Process

2020 ◽  
Vol 846 ◽  
pp. 237-242
Author(s):  
Zdeněk Prošek ◽  
Pavla Ryparová ◽  
Pavel Tesárek
Keyword(s):  
Culture Media ◽  
Microscopic Analysis ◽  
Precipitation Process ◽  
Carbonate Precipitation ◽  
Self Healing ◽  
Calcium Carbonate Precipitation ◽  
Cement Pastes ◽  
X Ray ◽  
Healing Agent ◽  
Calcium Precipitation

Cracks affect the durability of concrete by increasing its permeability. Self-healing materials can begin repairing themselves immediately after creating a crack. This is a big advantage of self-healing materials. In this study, effect of self-healing agents based on calcium carbonate precipitation for concrete is monitored for three months. Bacillus pseudofirmus was chosen as a self-healing agent and was tested on old cement pastes. Calcium precipitation was analyzed by scanning electron microscope with Energy-dispersive X-ray spectroscopy. The effect of added spontaneous calcination, culture media, bacteria and Ca2+ was monitored.

scholarly journals Agricultural by-products and oyster shell as alternative nutrient sources for microbial sealing of early age cracks in mortar

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Minyoung Hong ◽  
Indong Jang ◽  
Yongjun Son ◽  
Chongku Yi ◽  
Woojun Park
Keyword(s):  
Calcium Carbonate ◽  
Calcium Ions ◽  
Oyster Shell ◽  
Carbonate Precipitation ◽  
Sporulation Medium ◽  
Calcium Carbonate Precipitation ◽  
X Ray ◽  
Sesame Meal ◽  
Calcium Sources ◽  
By Products

AbstractBio-concrete using bacterially produced calcium carbonate can repair microcracks but is still relatively expensive due to the addition of bacteria, nutrients, and calcium sources. Agricultural by-products and oyster shells were used to produce economical bio-concrete. Sesame meal was the optimal agricultural by-product for low-cost spore production of the alkaliphilic Bacillus miscanthi strain AK13. Transcriptomic dataset was utilized to compare the gene expressions of AK13 strain under neutral and alkaline conditions, which suggested that NaCl and riboflavin could be chosen as growth-promoting factors at alkaline pH. The optimal levels of sesame meal, NaCl, and riboflavin were induced with the central composite design to create an economical medium, in which AK13 strain formed more spores with less price than in commercial sporulation medium. Calcium nitrate obtained from nitric acid treatment of oyster shell powder increased the initial compressive strength of cement mortar. Non-ureolytic calcium carbonate precipitation by AK13 using oyster shell-derived calcium ions was verified by energy-dispersive X-ray spectroscopy and X-ray diffraction analysis. Stereomicroscope and field emission scanning electron microscopy confirmed that oyster shell-derived calcium ions, along with soybean meal-solution, increased the bacterial survival and calcium carbonate precipitation inside mortar cracks. These data suggest the possibility of commercializing bacterial self-healing concrete with economical substitutes for culture medium, growth nutrient, and calcium sources.

scholarly journals Insights into the influence of cell concentration in design and development of microbially induced calcium carbonate precipitation (MICP) process

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254536
Author(s):  
Raja Murugan ◽  
G. K. Suraishkumar ◽  
Abhijit Mukherjee ◽  
Navdeep K. Dhami
Keyword(s):  
Calcium Carbonate ◽  
Bacterial Cell ◽  
Cell Concentration ◽  
Carbonate Precipitation ◽  
Precipitation Kinetics ◽  
Calcium Carbonate Precipitation ◽  
Design And Development ◽  
Engineering Applications ◽  
X Ray ◽  
Cell Numbers

Microbially induced calcium carbonate precipitation (MICP) process utilising the biogeochemical reactions for low energy cementation has recently emerged as a potential technology for numerous engineering applications. The design and development of an efficient MICP process depends upon several physicochemical and biological variables; amongst which the initial bacterial cell concentration is a major factor. The goal of this study is to assess the impact of initial bacterial cell concentration on ureolysis and carbonate precipitation kinetics along with its influence on the calcium carbonate crystal properties; as all these factors determine the efficacy of this process for specific engineering applications. We have also investigated the role of subsequent cell recharge in calcium carbonate precipitation kinetics for the first time. Experimental results showed that the kinetics of ureolysis and calcium carbonate precipitation are well-fitted by an exponential logistic equation for cell concentrations between optical density range of 0.1 OD to 0.4 OD. This equation is highly applicable for designing the optimal processes for microbially cemented soil stabilization applications using native or augmented bacterial cultures. Multiple recharge kinetics study revealed that the addition of fresh bacterial cells is an essential step to keep the fast rate of precipitation, as desirable in certain applications. Our results of calcium carbonate crystal morphology and mineralogy via scanning electron micrography, energy dispersive X-ray spectroscopy and X-ray diffraction analysis exhibited a notable impact of cell number and extracellular urease concentration on the properties of carbonate crystals. Lower cell numbers led to formation of larger crystals compared to high cell numbers and these crystals transform from vaterite phase to the calcite phase over time. This study has demonstrated the significance of kinetic models for designing large-scale MICP applications.

Sign in / Sign up

Export Citation Format

Share Document