Experimental Study of EICP Combined with Organic Materials for Silt Improvement in the Yellow River Flood Area

Yuan, Hua; Ren, Guanzhou; Kang, Liu; Wei, Zheng; Zhao, Zhongwei

doi:10.3390/app10217678

Cited by 37 publications

(20 citation statements)

References 41 publications

(67 reference statements)

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“…Canavalia ensiformis is a known plant to be rich in urease enzyme (Yuan et al, 2020). In the present work, urease enzyme was extracted from Canavalia ensiformis.…”

Section: Urease Extractionmentioning

confidence: 99%

The Effect of Calcium Source on Pb and Cu Remediation Using Enzyme-Induced Carbonate Precipitation

Wang

Cheng

Xue

2022

Front. Bioeng. Biotechnol.

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Heavy metal contamination not only causes threat to human health but also raises sustainable development concerns. The use of traditional methods to remediate heavy metal contamination is however time-consuming, and the remediation efficiency may not meet the requirements as expected. The present study conducted a series of test tube experiments to investigate the effect of calcium source on the lead and copper removals. In addition to the test tube experiments, numerical simulations were performed using Visual MINTEQ software package considering different degrees of urea hydrolysis derived from the experiments. The remediation efficiency degrades when NH4+ and OH− concentrations are not sufficient to precipitate the majority of Pb2+ and Cu2+. It also degrades when CaO turns pH into highly alkaline conditions. The numerical simulations do not take the dissolution of precipitation into account and therefore overestimate the remediation efficiency when subjected to lower Pb(NO3)2 or Cu(NO3)2 concentrations. The findings highlight the potential of applying the enzyme-induced carbonate precipitation to lead and copper remediations.

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“…Canavalia ensiformis is a known plant to be rich in urease enzyme (Yuan et al, 2020). In the present work, urease enzyme was extracted from Canavalia ensiformis.…”

Section: Urease Extractionmentioning

confidence: 99%

The Effect of Calcium Source on Pb and Cu Remediation Using Enzyme-Induced Carbonate Precipitation

Wang

Cheng

Xue

2022

Front. Bioeng. Biotechnol.

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“…The rates of carbonate precipitation and preparation method affect strength gain in the EICP technique. In general, the efficiency of EICP is lower than the MICP method [45]. Furthermore, the cost of EICP is another concern when using it in practice [46].…”

Section: Introductionmentioning

confidence: 99%

Strength and Durability of Cement-Treated Lateritic Soil

et al. 2021

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The transportation infrastructure, including low-volume roads in some regions, needs to be constructed on weak ground, implying the necessity of soil stabilization. Untreated and cement-treated lateritic soil for low-volume road suitability were studied based on Malaysian standards. A series of unconfined compressive strength (UCS) tests was performed for four cement doses (3%, 6%, 9%, 12%) for different curing times. According to Malaysian standards, the study suggested 6% cement and 7 days curing time as the optimum cement dosage and curing time, respectively, based on their 0.8 MPa UCS values. The durability test indicated that the specimens treated with 3% cement collapsed directly upon soaking in water. Although the UCS of 6% cement-treated specimens decreased against wetting–drying (WD) cycles, the minimum threshold based on Malaysian standards was still maintained against 15 WD cycles. On the contrary, the durability of specimens treated with 9% and 12% cement represented a UCS increase against WD cycles. FESEM results indicated the formation of calcium aluminate hydrate (CAH), calcium silicate hydrate (CSH), and calcium aluminosilicate hydrate (CASH) as well as shrinking of pore size when untreated soil was mixed with cement. The formation of gels (CAH, CSH, CASH) and decreasing pore size could be clarified by EDX results in which the increase in cement content increased calcium.

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“…The decrease of sand porosity is considered the main factor for the decrease of brittleness of fiber-reinforced EICP-treated sand [ 35 , 36 , 37 ]. By absorbing a large amount of CaCO 3 crystals, the fiber weakens the characteristic of equal thickness distribution of CaCO 3 on the surface of sand particles [ 38 ], forming a system of “fiber–CaCO 3 –sand particles” [ 39 ]. At the same time, some pores between sand particles were filled with spherical CaCO 3 , which was due to the large amount of soybean urease solution stored between fiber and sand particles, where CaCO 3 crystallization was regulated by organic matter.…”

Section: Discussionmentioning

confidence: 99%

Effect of Incorporating Polyvinyl Alcohol Fiber on the Mechanical Properties of EICP-Treated Sand

et al. 2021

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Enzyme-induced calcium carbonate precipitation (EICP) technology can improve the strength of treated soil. But it also leads to remarkable brittleness of the soil. This study used polyvinyl alcohol (PVA) fiber combined with EICP to solidify sand. Through the unconfined compressive strength (UCS) test, the effect of PVA fiber incorporation on the mechanical properties of EICP-solidified sand was investigated; the distribution of CaCO3 in the sample and the microstructure of fiber-reinforced EICP-treated sand were explored through the calcium carbonate content (CCC) test and microscopic experiment. Compared with the sand treated by EICP, the strength and stiffness of the sand reinforced by the fiber combined with EICP were greatly improved, and the ductility was also improved to a certain extent. However, the increase of CCC was extremely weak, and the inhomogeneity of CaCO3 distribution was enlarged; the influence of fiber length on the UCS and CCC of the treated sand was greater than that of the fiber content. The improvement of EICP-solidified sand by PVA fiber was mainly due to the formation of a “fiber–CaCO3–sand” spatial structure system through fiber bridging, not the increase of CCC.

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Experimental Study of EICP Combined with Organic Materials for Silt Improvement in the Yellow River Flood Area

Cited by 37 publications

References 41 publications

The Effect of Calcium Source on Pb and Cu Remediation Using Enzyme-Induced Carbonate Precipitation

The Effect of Calcium Source on Pb and Cu Remediation Using Enzyme-Induced Carbonate Precipitation

Strength and Durability of Cement-Treated Lateritic Soil

Effect of Incorporating Polyvinyl Alcohol Fiber on the Mechanical Properties of EICP-Treated Sand

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