Micro-structural characteristics deterioration of intact loess under acid and saline solutions and resultant macro-mechanical properties

Hu, Wenle; Cheng, Wen-Chieh; Wang, Lin; Xue, Zhong-Fei

doi:10.1016/j.still.2022.105382

Cited by 92 publications

(11 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Heavy metal contamination in the soil and underground water seriously threatens surrounding fragile environments and human health ( Kim et al, 2001 ; Mohan et al, 2006 ; Bai et al, 2017 ; Chang et al, 2019 ; Chen et al, 2022a ; Hu et al, 2020 ; Bai et al, 2021 ; Hu et al, 2021 ; Liu et al, 2021 ; Xue et al, 2021 ; Hu et al, 2022 ; Wang et al, 2022 ). Such heavy metal contamination remediation by the traditional soil flushing measure is deemed time-consuming and costly since heavy metal ions are easily adsorbed by soil particles, and intensive industrial activities further aggravate heavy metal contamination ( Yang et al, 2014 ; An et al, 2019 ; Kumar and Dwivedi, 2019 ; Bai et al, 2021 ; Cheng et al, 2021 ; Duan et al, 2021 ; Wei et al, 2021 ; Yuan et al, 2021 ; Chen et al, 2022b ).…”

Section: Introductionmentioning

confidence: 99%

Effects of the Urease Concentration and Calcium Source on Enzyme-Induced Carbonate Precipitation for Lead Remediation

et al. 2022

Self Cite

View full text Add to dashboard Cite

Heavy metal contamination during the rapid urbanization process in recent decades has notably impacted our fragile environments and threatens human health. However, traditional remediation approaches are considered time-consuming and costly, and the effect sometimes does not meet the requirements expected. The present study conducted test tube experiments to reproduce enzyme-induced carbonate precipitation applied to lead remediation under the effects of urease concentration and a calcium source. Furthermore, the speciation and sequence of the carbonate precipitation were simulated using the Visual MINTEQ software package. The results indicated that higher urease concentrations can assure the availability of CO32− during the enzyme-induced carbonate precipitation (EICP) process toward benefiting carbonate precipitation. The calcium source determines the speciation of carbonate precipitation and subsequently the Pb remediation efficiency. The use of CaO results in the dissolution of Pb(OH)2 and, therefore, discharges Pb ions, causing some difficulty in forming the multi-layer structure of carbonate precipitation and degrading Pb remediation. The findings of this study are useful in widening the horizon of applications of the enzyme-induced carbonate precipitation technology to heavy metal remediation.

show abstract

Section: Introductionmentioning

confidence: 99%

Effects of the Urease Concentration and Calcium Source on Enzyme-Induced Carbonate Precipitation for Lead Remediation

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…Porous media like coal, rock, and clay have been used to evaluate the fractal features using the thermodynamic law-based model (Friesen and Mikula, 1987;Hu et al, 2022). According to the thermodynamic law, the results of fractal analysis of the specimens before and after collapsibility also showed a strong correlation.…”

Section: The Fractal Dimension (Dn) Determined By the Thermodynamic L...mentioning

confidence: 99%

Change in Microstructure and Fractal Characteristics of Intact and Compacted Loess due to its Collapsibility

Zhang,

Shao,

Shao

et al. 2023

Preprint

View full text Add to dashboard Cite

This work aimed to examine the fractal dimension and difference law of intact and compacted loess before and after collapse. The uniaxial compression tests were performed to obtain specimens under different vertical stresses, and mercury intrusion porosimetry (MIP) tests were conducted to determine the pore size distribution (PSD). Three models were selected to determine the fractal dimensions based on PSD. As a result, the pores were classified into ultra-micropores (d < 0.1 µm), micropores (0.1 µm < d < 2 µm), small pores (2 µm < d < 10 µm), and large pores (d > 10 µm). When the fractal dimensions were determined using the capillary pressure model, there were three fractal intervals (Ds1, Ds2, and Ds3), with only Ds1 and Ds2 meeting the definition of fractal dimension. Ds1 increased considerably after the collapse, but Ds2 declined. The thermodynamic law-based model presented the best linear fit, and there was only one fractal interval. The fractal dimension Dn increased dramatically after the specimen was wet collapsed. Combined with fractal theory, it revealed that collapse changed the pore uniformity and complexity of the loess. After collapse, the microscopic pores of the loess became coarser and more complicated.

show abstract

“…The mobility or solubility of heavy metals can transform them from the solid phase to the solution phase, thereby increasing their bioavailability ( Bolan et al, 2014 ; Bai et al, 2020 , Bai et al, 2021c ; Yang et al, 2021 ; Xue et al, 2022 ). Therefore, immobilizing heavy metals is considered to be of great necessity in order to reduce their bioavailability ( Li et al, 2013 ; Khadim et al, 2019 ; Cheng et al, 2021 ; Hu et al, 2021 ; Hu et al, 2022 ; Wang et al, 2022; Wang et al, 2022 ; Wang et al, 2022 ). To this end, chemical precipitation, electroremediation, and ion-exchange and adsorption have been widely adopted as countermeasures.…”

Section: Introductionmentioning

confidence: 99%

Effects of Bacterial Culture and Calcium Source Addition on Lead and Copper Remediation Using Bioinspired Calcium Carbonate Precipitation

Xue

Cheng

Wang

et al. 2022

Front. Bioeng. Biotechnol.

Self Cite

View full text Add to dashboard Cite

Lead and copper ions from wastewater induced by metallurgical processes are accumulated in soils, threatening plant and human health. The bioinspired calcium carbonate precipitation is proven effective in improving the cementation between soil particles. However, studies on capsulizing heavy metal ions using the bioinspired calcium carbonate precipitation are remarkably limited. The present study conducted a series of test tube experiments to investigate the effects of bacterial culture and calcium source addition on the remediation efficiency against lead and copper ions. The calcium carbonate precipitation was reproduced using the Visual MINTEQ software package to reveal the mechanism affecting the remediation efficiency. The degradation in the remediation efficiency against lead ions relies mainly upon the degree of urea hydrolysis. However, higher degrees of urea hydrolysis cause remediation efficiency against copper ions to reduce to zero. Such high degree of urea hydrolysis turns pH surrounding conditions into highly alkaline environments. Therefore, pursuing higher degrees of urea hydrolysis might not be the most crucial factor while remedying copper ions. The findings shed light on the importance of modifying pH surrounding conditions in capsulizing copper ions using the bioinspired calcium carbonate precipitation.

show abstract

Micro-structural characteristics deterioration of intact loess under acid and saline solutions and resultant macro-mechanical properties

Cited by 92 publications

References 57 publications

Effects of the Urease Concentration and Calcium Source on Enzyme-Induced Carbonate Precipitation for Lead Remediation

Effects of the Urease Concentration and Calcium Source on Enzyme-Induced Carbonate Precipitation for Lead Remediation

Change in Microstructure and Fractal Characteristics of Intact and Compacted Loess due to its Collapsibility

Effects of Bacterial Culture and Calcium Source Addition on Lead and Copper Remediation Using Bioinspired Calcium Carbonate Precipitation

Contact Info

Product

Resources

About