scholarly journals Revealing the Enhancement and Degradation Mechanisms Affecting the Performance of Carbonate Precipitation in EICP Process

2021 ◽  
Vol 9 ◽  
Author(s):  
Wenle Hu ◽  
Wen-Chieh Cheng ◽  
Shaojie Wen ◽  
Ke Yuan
Keyword(s):  
Chinese Culture ◽  
Test Tube ◽  
Carbonate Precipitation ◽  
Magnesium Ions ◽  
Degradation Mechanisms ◽  
Nw China ◽  
Leading Role ◽  
Urease Enzyme ◽  
Heritage Buildings ◽  
Potential Use

Given that acid-rich rainfall can cause serious damage to heritage buildings in NW China and subsequently accelerate their aging problem, countermeasures to protect their integrity and also to preserve the continuity of Chinese culture are in pressing need. Enzyme-induced carbonate precipitation (EICP) that modifies the mechanical properties of the soil through enhancing the interparticle bonds by the precipitated crystals and the formation of other carbonate minerals is under a spotlight in recent years. EICP is considered as an alternative to the microbial-induced carbonate precipitation (MICP) because cultivating soil microbes are considered to be challenging in field applications. This study conducts a series of test tube experiments to reproduce the ordinary EICP process, and the produced carbonate precipitation is compared with that of the modified EICP process subjected to the effect of higher MgCl2, NH4Cl, and CaCl2 concentrations, respectively. The modified EICP, subjected to the effect of higher MgCl2 concentrations, performs the best with the highest carbonate precipitation. The enhancement mechanism of carbonate precipitation is well interpreted through elevating the activity of urease enzyme by introducing the magnesium ions. Furthermore, the degradation of carbonate precipitation presents when subjected to the effect of higher NH4Cl concentration. The decreasing activity of urease enzyme and the reverse EICP process play a leading role in degrading the carbonate precipitation. Moreover, when subjected to the effect of higher CaCl2 concentrations, the slower rate of urea hydrolysis and the decreasing activity of urease enzyme are primarily responsible for forming the “hijacking” phenomenon of carbonate precipitation. The findings of this study explore the potential use of the EICP technology for the protection of heritage buildings in NW China.

scholarly journals Biocementation of Calcareous Beach Sand Using Enzymatic Calcium Carbonate Precipitation

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 888 ◽  
Author(s):  
Ahmed Miftah ◽  
Hamed Khodadadi Tirkolaei ◽  
Huriye Bilsel
Keyword(s):  
Test Tube ◽  
Beach Sand ◽  
Ammonium Concentration ◽  
Carbonate Content ◽  
Carbonate Precipitation ◽  
Calcium Carbonate Precipitation ◽  
Time Intervals ◽  
Urease Enzyme ◽  
Sodium Magnesium ◽  
Chloride Sulfate

Beach sands are composed of a variety of minerals including quartz and different carbonate minerals. Seawater in beach sand contains several ions such as sodium, magnesium, calcium, chloride, sulfate, and potassium. These variations in mineralogy and the presence of salts in beach sand may affect the treatment via enzyme-induced carbonate precipitation (EICP). In this study, set test tube experiments were conducted to evaluate the precipitation kinetics and mineral phase of the precipitates in the presence of zero, five, and ten percent seawater (v/v). The kinetics were studied by measuring electrical conductivity (EC), pH, ammonium concentration, and carbonate precipitation mass in EICP solution at different time intervals. A beach sand was also treated using EICP solution containing zero and ten percent seawater at one, two, and three cycles of treatment. Unconfined compressive strength (UCS), carbonate content, and mineralogy of the precipitates in the treated specimens were evaluated. The kinetics study showed that the rate of urea hydrolysis and the rate of precipitation for zero, five, and ten percent seawater were similar within the first 16 h of the reaction. After 16 h, it was observed that the rates dropped in the solution containing seawater, which might be attributed to the faster decay rate of urease enzyme when seawater is present. All the precipitates from the test tube experiments contained calcite and vaterite, with an increase in vaterite content by increasing the amount of seawater. The presence of ten percent seawater was found to not significantly affect the UCS, carbonate content, and mineralogy of the precipitates of the treated beach sand.

scholarly journals Architectural Models and Their Contexts in China’s 20th-Century Architectural Heritage: An Overview

2019 ◽  
Vol 3 (4) ◽  
pp. 1-13 ◽  
Author(s):  
Qing Chang
Keyword(s):  
Chinese Culture ◽  
Morphological Evolution ◽  
Late Modernism ◽  
Architectural Heritage ◽  
Tiananmen Square ◽  
Heritage Buildings ◽  
Modernist Architecture ◽  
Treaty Ports ◽  
Post Industrial ◽  
The Impact

AbstractThe article explores the morphological evolution of China’s 20th-century architecture chronologically. Chinese Neoclassicism has played a major role in forming the 20th-century heritage buildings surviving today. The phenomenon of Neoclassicism emerged because of the late arrival of China’s modernisation and industrialisation process compared with the West. In turn, in accepting and contesting Western culture, the Chinese elite have consciously relied upon architecture as a vehicle to uphold visible symbols of national Chinese identity and traditional Chinese culture. Meanwhile, in the foreign settlements of the treaty ports such as Shanghai, the Western Neoclassical style, along with other imported construction trends, also forms part of China’s 20th-century architectural heritage. Western Neoclassicism’s influence on China’s new architecture became even more evident in the mid-20th century, with the modern architectural heritage in Tiananmen Square as its exemplar. Nevertheless, the impact of Western modernist architecture on China’s architecture was minimal. It was not until the 1980s, as China reopened to the world, that various schools of thought from the post-industrial West flowed into China, which significantly enriched the types and sources of China’s 20th-century architectural heritage. Modern Classicism, late Modernism and Postmodernism all found their way into China’s contemporary architecture.

Utilization of Soybeans as Bio-Catalyst in Calcite Precipitation Method for Repairing Cracks in Concrete

2021 ◽  
Vol 23 (2) ◽  
pp. 104-113
Author(s):  
Rama Zaky Rahmawan ◽  
Muhammad Fauzan ◽  
Heriansyah Putra
Keyword(s):  
Compressive Strength ◽  
Precipitation Method ◽  
Carbonate Precipitation ◽  
Self Healing ◽  
Soybean Flour ◽  
Injection Solution ◽  
Calcite Precipitation ◽  
Soybean Extract ◽  
Urease Enzyme ◽  
Lower Tensile Strength

Concrete is a material that has high compressive strength. However, concrete has a lower tensile strength than its compressive strength. As a result, the concrete often cracks and allows the entry of harmful substances such as  dan   causing corrosion of the reinforcement. Therefore, the repair method began to shift from the conventional way to the concept of self-healing concrete which involves the deposition of CaCO3. Precipitation can be done by the enzymatically – induced carbonate precipitation (EICP) method through a combination of urease, urea, and CaCl2 into a solution. This research used soybean extract as a substitute for pure urease enzyme. Variations in the concentration of soybean flour used as injection solution were variations in the content of soybean flour 15 g/L because it produced an optimum calcite mass of 2.62 grams. As a result, there was an increase in the compressive strength of BI against BR. In addition, there was a decreased value of permeability and porosity and the number of injections carried out. The increase in compressive strength, decrease in permeability, and decrease in porosity in concrete is due to CaCO3 deposition in the concrete which can cover the pores and cracks in the concrete.

scholarly journals Synergy of Mg2+ and poly(aspartic acid) in additive-controlled calcium carbonate precipitation

CrystEngComm ◽  
2015 ◽  
Vol 17 (36) ◽  
pp. 6857-6862 ◽  
Author(s):  
Stefan L. P. Wolf ◽  
Kathrin Jähme ◽  
Denis Gebauer
Keyword(s):  
Calcium Carbonate ◽  
Aspartic Acid ◽  
Synergistic Effects ◽  
Carbonate Precipitation ◽  
Magnesium Ions ◽  
Calcium Carbonate Precipitation

Distinct synergistic effects of poly(aspartic acid) and magnesium ions found during CaCO3 precipitation are important for biomineralisation and antiscaling strategies.

Electrode Properties of Todorokite-type Tunnel-structured Manganese Oxide for Calcium Secondary Batteries

2016 ◽  
Vol 19 (2) ◽  
pp. 051-055 ◽  
Author(s):  
Shinya Suzuki ◽  
Tsubasa Kato ◽  
Hidetoshi Kawabata ◽  
Masaru Miyayama
Keyword(s):  
Manganese Oxide ◽  
Manganese Oxides ◽  
Reversible Capacity ◽  
Magnesium Ions ◽  
Charge Capacity ◽  
X Ray ◽  
Large Current ◽  
Large Current Density ◽  
X Ray Absorption ◽  
Potential Use

The electrode properties of todorokite-type tunnel-structured manganese oxides (TodMO) were examined for their potential use as cathode materials in calcium batteries. TodMO with a chemical composition of Mg0.19Na0.07MnO2·0.37H2O was prepared through hydrothermal treatment of layer-structured manganese oxide using magnesium ions as interlayer guest ions. The TodMO exhibited a dis-charge and charge capacity of 100 and 80 mAh g−1, respectively, at a relatively large current density of 100 mA g−1. The reaction mecha-nism was studied in detail using X-ray absorption spectroscopy measurements. Consequently, it became clear that the newly formed Mn3+-compound converted from TodMO is responsible for the reversible capacity.

scholarly journals The Potential Use of Resveratrol for Cancer Prevention

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4506 ◽  
Author(s):  
Dominique Vervandier-Fasseur ◽  
Norbert Latruffe
Keyword(s):  
Cancer Prevention ◽  
Test Tube ◽  
New Drugs ◽  
Preclinical Studies ◽  
Clinical Protocol ◽  
Established Cell Lines ◽  
Established Cell ◽  
And Control ◽  
Potential Use ◽  
Methods Of Application

In addition to the traditional treatments of cancer and cancer prevention, the use of natural compounds, especially those found in food, should be considered. To clarify if resveratrol has the potential for cancer prevention and the possibility of use in therapy, the following must be taken into account: data from epidemiology, clinical protocol (case and control), preclinical studies (lab animals), use of established cell lines as models of cancer cells, test tube assays (enzymes activities), and requirements of nanotechnologies in order to discover new drugs to fight cancer. From this perspective and future expected advances, more information is needed such as improved efficacy, methods of application, and the synergistic sensitization of resveratrol as an adjuvant. In addition, resveratrol nanoformulation is considered to overcome its weak bioavailability.

scholarly journals Potential of fungi to produce bioconcrete

2020 ◽  
Vol 5 ◽  
pp. 157-162
Author(s):  
Carolina Martuscelli ◽  
Célia Soares ◽  
Nelson Lima ◽  
Aires Camões
Keyword(s):  
Electron Microscopy ◽  
Penicillium Chrysogenum ◽  
Chemical Constituents ◽  
Carbonate Precipitation ◽  
Self Healing ◽  
Calcium Carbonate Precipitation ◽  
Sustainable Solutions ◽  
Induction Process ◽  
Potential Use ◽  
Scanning Electron

The cracks in concrete reduce their resistance capacity and allow the entry of harmful agents both for their microstructure and for the reinforcements located inside the structure. Several studies have been done to promote sustainable solutions for this problem. The microbiologically induced calcium carbonate precipitation (MICCP) is an alternative to traditionally used methods and a way to reduce the environmental impact of using more cement and polymers. Most of the biocementation studies to fill cracks or to promote bio self-healing on concrete present bacteria as the microorganisms responsible for the CaCO3 induction process. Fungi are potentially better for the biocementation process because they have more biomass and some develop filaments that can be used as microfibers on materials. Thus, the present work proposes the development of a methodology to analyse the potential use of two urease-positive fungi (Penicillium chrysogenum MUM 9743 and Neurospora crassa MUM 9208) to produce bioconcrete. The microstructure and chemical constituents of biocrystals formed due to MICCP were observed under Scanning Electron Microscopy (SEM). SEM showed fungal mycelia as bio-based fiber in bioconcrete and clusters of probable calcite crystals on and around mycelia. Both fungi were able to promote biocimentation of sand.

scholarly journals Optimisation of chemical constituents on enzyme-induced carbonate precipitation in test-tube and soil

2021 ◽  
pp. 1-19
Author(s):  
Isaac Ahenkorah ◽  
Md Mizanur Rahman ◽  
Md Rajibul Karim ◽  
Simon Beecham
Keyword(s):  
Chemical Constituents ◽  
Test Tube ◽  
Carbonate Precipitation

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.

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