Calcite Nanoparticles Research Articles

Bio-inspired synthesis of nanocrystalline calcite demonstrating significant improvement in mechanical properties of concrete: a construction-nanobiotechnology approach.

The bioinspired synthesis of construction material, known as biocement, represents a significant advancement in addressing the environmental sustainability issues associated with traditional cement use in the built environment. Biocement is produced through the process of microbially induced bio-mineralization (MIBM), which offers a promising alternative or supplement to conventional cement, potentially reducing its consumption. Despite extensive literature on the application of biocement in construction biotechnology, the fundamental mechanisms underlying its ability to enhance concrete quality remain poorly understood. This study focuses on the kinetics of biomineral synthesis by two Bacillus species; Bacillus megaterium RB05 and Bacillus foraminis DRG5, to identify the most effective strain for biomineralization. Bioconcrete specimens were created by adding inoculum containing Bacillus megaterium RB05 cells with a nutrient solution to the concrete mixture in a layer-by-layer approach. After 28days of water curing, nanoparticles of CaCO3, ranging in size from 27 to 82nm, were produced in the bioconcrete specimens. The resulting concrete, containing nanocrystalline biogenic calcite, demonstrated significant improvements in mechanical properties. Specifically, compressive and tensile strengths of the bioconcrete, tested using a universal testing machine (UTM), increased by 7.69 ± 0.08% and 22 ± 0.1%, respectively, after 72h of curing. Additionally, the biocement was found to exhibit an organic-inorganic hybrid nature, as identified by TEM, EDAX, FESEM, FTIR, and XRD analyses. The enhanced mechanical properties were attributed to the high surface-to-volume ratio and hybrid nature of the calcite nanoparticles. The findings of this investigation are encouraging, suggesting the potential development of future green and self-sustainable construction materials or bioconcrete.

Optimizing the fluoride removal from drinking water through adsorption with mesoporous magnetic calcite nanocomposites

Fluoride (F−) contamination in groundwater is a global concern arising from natural processes and human activities. This study investigates the adsorption of F− using surface-activated magnetic calcite nanocomposites (NCs) synthesized via co-precipitation assisted wet-impregnation (CP-WI). Various Fe3O4 loadings and calcination temperatures (300 °C and 500 °C) were explored to optimize synthesis parameters. Batch adsorption experiments were conducted to assess the performance of synthesized nanoparticles (NPs) and nanocomposites (NCs). BET, FTIR spectroscopy, X-ray diffraction, and SEM characterization techniques were employed to analyze the physicochemical properties, including surface functional groups, crystallite size, and morphology. The adsorption process was investigated using RSM statistical design with adsorbent dose (A) and F− concentration (B) as independent variables. 0.5Fe-C-NC-5, calcined at 500 °C, exhibited superior adsorption capacity (7.81 mg/g) compared to Fe3O4 and calcite NPs (6.57 mg/g and 6.81 mg/g, respectively). Maximum F− adsorption occurred within 10 min of contact time. NPs and NCs that were exposed to higher calcination temperatures, reaching up to 500 °C, showed an increase in crystallite development while experiencing a reduction in surface area and an enlargement of pore size compared to those treated at lower temperatures. The BET analysis revealed a narrow, slit-like mix of microporous and mesoporous surface with a type IV isotherm and H3 hysteresis loop, indicating multilayer adsorption followed by capillary condensation. The SEM images displayed columnar shapes of CaCO3 polymorph in the prepared Fe3O4-calcite NP and Fe–C NP, which can be attributed to lower calcination or synthesis temperatures.

Eggshells from agro-industrial waste for the recovery of lime, portlandite, and calcite nanoparticles through the lime cycle: A circular economic approach

This work focused on the study the lime cycle for samples obtained from agro-waste of chicken eggshells, mainly composed of calcite (CaCO3), in the context of circular economy concept and for nanotechnological applications. The thermal analysis (TGA/DSC) analyzed the transformation temperatures of the individual phases. Based on these results, the eggshells were calcined at 850 °C to ensure the complete conversion of calcite into lime (CaO). The lime was then hydrated with distilled water to convert it into portlandite (Ca(OH)2). The samples belonging to this cycle were structurally characterized using X-ray diffraction, and the vibrational states were identified using Fourier transform infrared spectroscopy. Scanning Electron Microscopy was used to study the changes in morphology and crystallite size. This showed that all compounds along the cycle are microparticles consisting of nanocrystals, which correlated with the Dynamic Light Scattering results. The Zeta potential was used to determine the surface charge of the samples and shown a variety of results due to the different transformations during the cycle and the mineral content of the eggshells as shown by the results of the ICP technique.

Microfluidics for Carbonate Rock Improved Oil Recovery: Some Lessons from Fabrication, Operation, and Image Analysis

Summary After the successful implementation of lab-on-a-chip technology in chemical and biomedical applications, the field of petroleum engineering is currently developing microfluidics as a platform to complement traditional coreflooding experiments. Potentially, microfluidics can offer a fast, efficient, low-footprint, and low-cost method to screen many variables such as injection brine composition, reservoir temperature, and aging history for their effect on crude oil (CRO) release, calcite dissolution, and CO2 storage at the pore scale. Generally, visualization of the fluid displacements is possible, offering valuable mechanistic information. Besides the well-known glass- and silicon-based chips, microfluidic devices mimicking carbonate rock reservoirs are currently being developed as well. In this paper, we discuss different fabrication approaches for carbonate micromodels and their associated applications. One approach in which a glass micromodel is partially functionalized with calcite nanoparticles is discussed in more detail. Both the published works from several research groups and new experimental data from the authors are used to highlight the current capabilities, limitations, and possible extensions of microfluidics for studying carbonate rock systems. The presented insights and reflections should be very helpful in guiding the future designs of microfluidics and subsequent research studies.

Sustainable production of nanolime using plant extracts by fermentation: A traditional approach towards conservation of heritage structures

Nanolimes have emerged as efficient consolidants for the conservation of historic and heritage structures. This research investigates an effective, economical, and sustainable way of synthesizing nanolimes using hydraulic lime and natural plant extracts. The lime is fermented with aqueous organic extract for 14 days to produce nanolimes. The fermented compounds in liquid phases and the organic extract were identified using high-performance liquid chromatography (HPLC) and gas chromatography with mass spectrometry (GC-MS). Alcohols, which are substantial fermentation byproducts, were found to aid the nanoscale dispersion of portlandite particles. The narrow size distribution and mean particle size of 130–290 nm in seven-day fermented samples were able to penetrate deeper into treated surface strata for better conservation of structures. The presence of portlandite and calcite nanoparticles observed by X-ray diffraction in nanolime assisted to fill the pores that are too big for nano-portlandite alone and intensifies its ability to hold the grains of the treated surface. The biomineralization process resulted in the development of carbonate compounds ranging in size from 0.4 to 50 nm, thus rendering nanolime as more effective and facilitating the filling of nanopores smaller than 100 nm, which eventually signifies the durability of structure. Ultimately, this research emphasizes importance of nanotechnology in resurrecting tangible heritage.

A computer simulation study of extended DLVO interactions between calcite nanoparticles and real rough surfaces

The interaction energy between calcite nanoparticles and real rough surfaces in calcium carbonate supersaturated solutions was numerically calculated according to the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory and the surface element integration method. Three different surfaces, namely polished stainless steel, plasma-treated stainless steel, and fluorine-doped diamond-like carbon film, were prepared by mechanical polishing, plasma sputtering and film deposition, and characterized by atomic force microscopy. These images were then used as inputs in numerical simulations, where particle radius, solution concentration, surface electric potential, and surface tension components were varied. A total of 4052 simulations were performed. It was obtained that smaller particles interact more strongly with the surface and therefore are more attracted or repelled by the surface than larger ones. The effect of surface roughness on the particle interaction, however, depends on the physicochemical properties of the system and, therefore, a given surface may change its fouling behavior when the set of experimental conditions is changed. The effect of particle size on particle-surface interaction was found to be dependent on the relative sizes of the particle and the typical roughness features of the surface. A new local roughness metric – the minimum distance between the south pole of the particle and the rough substrate – can be used to predict the contact energy. These results may be important to engineer better antifouling surfaces for a wide range of applications, such as oil and gas exploitation and water treatment and desalination.

Experimental measurement and modeling of asphaltene adsorption onto iron oxide and lime nanoparticles in the presence and absence of water

Asphaltene precipitation and its adsorption on different surfaces are challenging topics in the upstream and downstream of the oil industries and the environment. In this research, the phenomenon of asphaltenes adsorption in the presence and absence of water on the surface of magnetite, hematite, calcite, and dolomite nanoparticles (NPs) was investigated. Five asphaltenes of different origins, four NPs as adsorbents and Persian Gulf water were used for three-phase (asphaltene/toluene solution + NPs + water) experiments. Characterization of asphaltenes and NPs was performed using Fourier transform infrared spectroscopic (FTIR), dynamic light scattering (DLS), elemental analysis, and field emission scanning electron microscopy (FESEM). Adsorption experiments were performed in two- (asphaltene/toluene solution + NPs) and three-phase systems. The results showed that the most effective parameters for asphaltene adsorption onto these NPs are the asphaltene composition, namely nitrogen content, and the aromaticity of asphaltenes. The significant effects of these parameters were also confirmed by the relevancy factor function as a sensitivity analysis. In the competition of asphaltene adsorption capacity by NPs, iron oxide NPs had the highest adsorption (Magnetite NPs > Hematite NPs > Calcite NPs > Dolomite NPs). From the results of the experiments in the presence of water phase, it could be pointed out that the asphaltenes adsorption onto the NPs was accompanied by a decrease compared to the experiments in the absence of water. The modeling also showed that physical adsorption has a significant contribution to the asphaltenes adsorption on the surface of iron oxides and lime NPs. The results of this research can assist in a better understanding of the asphaltene adsorption phenomenon and the role of iron oxide and lime NPs in solving this problem.

Antibacterial and Antibiofilm Activity of Calcite (CaCO3) Nanoparticles Synthesized from Chicken Eggshell

Background: The Calcite Calicium Carbonate Nanoparticles (CaCO3NPs) synthesized from the chicken eggshell (CES), this was done by crushing the shell and sieving.

Molecular Insights into the Impacts of Calcite Nanoparticles on Methane Hydrate Formation

Despite the potential broad utility of nanoparticles in hydrate-related fields, there remains a paucity of studies on the impacts of nanoparticles on gas hydrate formation. In this study, massive microsecond molecular dynamics simulations were performed to investigate the roles of calcite nanoparticles on the formation processes of methane hydrate. Our results indicate that calcite nanoparticles prefer to be in the water phase close to the water/gas interface. They inhibit methane hydrate nucleation because a layer of bound water with a thickness of 0.75 nm forms around each nanoparticle which results in an extremely low methane concentration region. Thus, methane hydrate nucleates away from the nanoparticle, and no clear connection between the nucleated hydrate and the nanoparticle is observed. The nanoparticles associate easily, and a water layer with a thickness of 1.15 nm forms between the associated nanoparticles. Moreover, methane hydrate growth is not influenced by calcite nanoparticles until the growth front approaches the bound water around the nanoparticle. These molecular insights of the impacts of calcite nanoparticles on methane hydrate formation are beneficial for the application of nanoparticles in hydrate mining and hydrate-related technologies.

In Situ Characterization of Carbonate/Oil/Water Interfacial Layers Using Advanced EM Techniques for Enhanced Oil Recovery

The visualization and characterization of the interactions between injection brine, oil, and carbonate rock play a major role in understanding the causative mechanisms behind wettability alteration and enhanced oil recovery. However, conventional imaging methods fail to provide such important analysis due to limited resolution and visualization capabilities. To address this gap, a cryogenic electron microscope (EM) and liquid-cell holder have been utilized in this study. The results from each of these techniques are discussed and compared. The liquid-cell transmission electron microscope (TEM) holder with an encapsulation function feature successfully enabled the direct observation and analysis of the liquid sample close to its native conditions. Energy-dispersive spectroscopy (EDS) analyses have been simultaneously utilized to provide the chemical mapping of the rock–fluid interfaces. These results provide, for the first time, nanoscale images of oil droplets, calcite nanoparticles, and dissolved salt ions in their native environment. The compositional distribution of multiple elements and elemental mapping of the structures in solution are also presented. The presented novel nanoscale characterization provides a new insight into the rock–oil–brine interactions, and this understanding can be critical to optimize the salinity and injection water compositions used for enhanced oil recovery in carbonate reservoirs.

High-Mg calcite nanoparticles within a low-Mg calcite matrix: A widespread phenomenon in biomineralization

During the process of biomineralization, organisms utilize various biostrategies to enhance the mechanical durability of their skeletons. In this work, we establish that the presence of high-Mg nanoparticles embedded within lower-Mg calcite matrices is a widespread strategy utilized by various organisms from different kingdoms and phyla to improve the mechanical properties of their high-Mg calcite skeletons. We show that such phase separation and the formation of high-Mg nanoparticles are most probably achieved through spinodal decomposition of an amorphous Mg-calcite precursor. Such decomposition is independent of the biological characteristics of the studied organisms belonging to different phyla and even kingdoms but rather, originates from their similar chemical composition and a specific Mg content within their skeletons, which generally ranges from 14 to 48 mol % of Mg. We show evidence of high-Mg calcite nanoparticles in the cases of six biologically different organisms all demonstrating more than 14 mol % Mg-calcite and consider it likely that this phenomenon is immeasurably more prevalent in nature. We also establish the absence of these high-Mg nanoparticles in organisms whose Mg content is lower than 14 mol %, providing further evidence that whether or not spinodal decomposition of an amorphous Mg-calcite precursor takes place is determined by the amount of Mg it contains. The valuable knowledge gained from this biostrategy significantly impacts the understanding of how biominerals, although composed of intrinsically brittle materials, can effectively resist fracture. Moreover, our theoretical calculations clearly suggest that formation of Mg-rich nanoprecipitates greatly enhances the hardness of the biomineralized tissue as well.

First and efficient bio-nano composite, SnO2/Calcite based on Cypress leaves and eggshell wastes, for cytotoxic effects on HepG2 liver cancer cell lines and its antioxidant and antimicrobial activity

The present study aimed to explain the influence of novel SnO2/Calcite bio-nano composite on HepG2 cell line, and its antioxidant, and antimicrobial properties. In this study, green fabrication of SnO2/Calcite bio-nano composite was synthesized based on cypress leaves and eggshell wastes, characterized structurally by SEM, TEM, XRD, EDAX, elemental analysis, and FT-IR for more information about this composite. We study the cytotoxic potential of SnO2/Calcite bio-nano composite against human liver cancer HepG2 cell line. In vitro free radical scavenging, total antioxidant capacity, and antimicrobial activity of this bio-nano composite were investigated. SnO2/Calcite bio-nano composite was displayed anti-cancer, antioxidant, and antimicrobial properties successfully. Also, the results suggest that SnO2/Calcite bio-nano composite holds more significant potential than calcite and SnO2 nanoparticles against bacteria and fungi. These results displayed that SnO2/Calcite bio-nano composite might be used for the design of novel anti-proliferative and antimicrobial bioagents.

Effects of trace Si impurities in water on the growth of calcite nanoparticles

Si impurities act as proton buffers in water and prevent the formation of the alkaline environment required for calcite growth.

Multispectral Assessment of Sweet Pepper (Capsicum annuum L.) Fruit Quality Affected by Calcite Nanoparticles.

Sweet pepper (Capsicum annuum L.) is one of the most important vegetable crops in the world because of the nutritional value of its fruits and its economic importance. Calcium (Ca) improves the quality of sweet pepper fruits, and the application of calcite nanoparticles in agricultural practice has a positive effect on the morphological, physiological, and physicochemical properties of the whole plant. The objectives of this study were to investigate the effect of commercial calcite nanoparticles on yield, chemical, physical, morphological, and multispectral properties of sweet pepper fruits using a combination of conventional and novel image-based nondestructive methods of fruit quality analysis. In the field trial, two sweet pepper cultivars, i.e., Šorokšari and Kurtovska kapija, were treated with commercial calcite nanoparticles (at a concentration of 3% and 5%, calcite-based foliar fertilizer (positive control), and water (negative control) three times during vegetation). Sweet pepper fruits were harvested at the time of technological and physiological maturity. Significant differences were observed between pepper cultivars as well as between harvests times. In general, application of calcite nanoparticles reduced yield and increased fruit firmness. However, different effects of calcite nanoparticles were observed on almost all properties depending on the cultivar. In Šorokšari, calcite nanoparticles and calcite-based foliar fertilizers significantly increased N, P, K, Mg, Fe, Zn, Mn, and Cu at technological maturity, as well as P, Ca, Mg, Fe, Zn, Mn, Cu, and N at physiological maturity. However, in Kurtovska kapija, the treatments increased only Ca at technological maturity and only P at physiological maturity. The effect of treatments on fruit morphological properties was observed only at the second harvest. In Šorokšari, calcite nanoparticles (3% and 5%) increased the fruit length, minimal circle area, and minimal circle radius, and it decreased the fruit width and convex hull compared to the positive and negative controls, respectively. In Kurtovska kapija, calcite nanoparticles increased the fruit width and convex hull compared to the controls. At physiological maturity, lower anthocyanin and chlorophyll indices were found in Kurtovska kapija in both treatments with calcite nanoparticles, while in Šorokšari, the opposite effects were observed.

Structural and chemical variations in Mg-calcite skeletal segments of coralline red algae lead to improved crack resistance

The calcareous alga Jania sp. is an articulated coralline red seaweed that is abundant in the shallow waters of oceans worldwide. We have previously demonstrated that its structure is highly intricate and exhibits hierarchical organization across multiple length scales from the macro to the nano scale. Moreover, we have proven that the inner pores of its structure are helical, conveying the alga greater compliance as compared to a cylindrical configuration. Herein, we reveal new insights into the structure of Jania sp., particularly, its crystallographic variations and the internal elemental distribution of Mg and Ca. We show that the high-Mg calcite cell wall nanocrystals of Jania sp. are arranged in layers with alternating Mg contents. Moreover, we show that this non-homogenous elemental distribution assists the alga in preventing fracture caused by crack propagation. We further reveal that each one of the cell wall nanocrystals in Jania sp. is not a single crystal as was previously thought, but rather comprises Mg-rich calcite nanoparticles demonstrating various crystallographic orientations, arranged periodically within the layered structure. We also show that these Mg-rich nanoparticles are present in yet another species of the coralline red algae, Corallina sp., pointing to the generality of this phenomenon. To the best of our knowledge this is a first report on the existence of Mg-rich nanoparticles in algal mineralized tissue. We envisage that our findings on the bio-strategy found in the algae to enhance their fracture toughness will have an impact on the design of structures with superior mechanical properties. Statement of significanceUnderstanding the structure-property relation in biomineralized tissues is of great importance in unveiling Nature's material design strategies, which form the basis for the development of novel structural materials. Crystallographic and elemental variations in the skeletal parts of the coralline red algae and their cumulative contribution to prevention of mechanical failure are yet poorly studied. Herein, we reveal that the high-Mg calcite cell wall nanocrystals of Jania sp. are arranged in layers with alternating Mg concentrations and that this organization facilitates crack deflection, thereby preventing catastrophic fracture. We further discovered that the nanocrystals contain incoherent Mg-rich nanoparticles and suggest that they form via spinodal decomposition of the Mg-ACC precursor and self-arrange periodically throughout the alga's mineralized cell wall, a phenomenon most likely to be widespread in high-Mg calcite biomineralization.

Carbon dioxide conversion into calcium carbonate nanoparticles using membrane gas absorption

Mineral carbonation in an aqueous solution is one of the practical strategies in carbon capture utilization and storage (CCUS). The wet carbonation can be further used to produce calcium carbonate nanoparticles with vast applications. Since the slow CO2 absorption affects the carbonation reaction, membrane gas absorption (MGA) with porous membranes was used in this study to enhance the mass transfer of CO2 gas into liquid absorbent for the carbonation of calcium-rich solution. The effects of sodium dodecyl sulphates (SDS) and poly(ethylene glycol) (PEG) on the properties of CaCO3 nanoparticles formed in wet carbonation were first studied. The calcite nanoparticles with particle size smaller than 25 nm were successfully produced, as proven in X-ray diffraction analysis and the transmission electron microscope images. Calcite nanoparticles with a BET surface area of 77.17 m2/g could adsorb 91.8 % of Congo red dye. The wet carbonation with surfactant-template was subsequently integrated with MGA. The pure CO2 absorption flux through the silanized polyvinylidene fluoride (PVDF)/TiO2 membrane enabled the formation of calcite nanoparticles in a calcium-rich solution containing a surfactant-template complex. The slow CO2 absorption flux of the commercial PVDF membrane with a hydrophobic surface cause failure to produce calcite with nano size.

Structural and Chemical Variations in the Skeletal Segments of Coralline Red Algae Lead to Improved Crack Resistance

Jania sp. is an articulated coralline red alga that is abundant in the shallow waters of oceans worldwide. We have previously demonstrated that its structure is highly intricate and exhibits hierarchical organization across multiple length scales from the macro to the nano scale. Moreover, we have proven that the inner pores of its structure are helical, conveying the alga greater compliance as compared to a cylindrical configuration. Herein, we reveal new insights on the structure of Jania sp., particularly on its crystallographic variations and the internal elemental distribution of Mg and Ca. We show that the high-Mg calcite cell wall nanocrystals of Jania sp. are arranged in layers with alternating Mg contents. Moreover, we show that this non-homogenous elemental distribution assists the alga in preventing fracture caused by crack propagation. We further discover that each one of the cell wall nanocrystals in Jania sp. is not a single crystal as was previously thought, but rather comprises Mg-rich calcite nanoparticles demonstrating various crystallographic orientations, arranged periodically within the layered structure. We also show that these Mg-rich nanoparticles are present in yet another specie of the coralline red algae, Corallina sp., pointing to the generality of this phenomenon. To the best of our knowledge this is a first report on the existence of Mg-rich nanoparticles in the coralline red algae mineralized tissue. We envisage that our findings on the bio-strategy found in the alga to enhance the fracture toughness will have an impact on the design of structures with superior mechanical properties.

Synthesis and polymorph controlling of calcite and aragonite calcium carbonate nanoparticles in a confined impinging-jets reactor

In this article, a confined-impinging-jets reactor (CIJR) was designed and tested successfully for the synthesis of calcium carbonate nanoparticles using the reactive precipitation method. The proposed CIJR comprised of two opposed nozzles placed in a cylindrical chamber. Effects of various operating and design parameters such as supersaturation, feed flow rate, nozzle diameter, reactor diameter, operating temperature, and surface-active agents on the mean particle size, particle size distribution, and the polymorphs of calcium carbonate nanoparticles were investigated carefully. By changing the supersaturation, reactor diameter, jets velocity, operating temperature, and the nozzle diameter, a wide range of calcium carbonate nanoparticles with mean particle sizes of smaller than 40 nm to larger than 160 nm was synthesized. Mixing intensity and control of parameters decrease the mean particle size and increase selectivity to the synthesis of calcite or aragonite nanoparticles compared to other synthesis devices. The use of high supersaturation values and nozzle diameter of 500 μm in the presence of sodium dodecyl sulfate surfactant result in the synthesis of nanoparticles with a mean particle size of 34 nm and a weight percentage of about 80 % of aragonite phase.

Local Electronic Structure of Calcite Investigated Using X-ray Absorption Spectroscopy at Different Span of Time.

For the present work, calcite nanoparticles was synthesized from calcium nitrate by annealing precursor at 300, 400, 500 and 600°C. Ca K-edge near edge X-ray absorption fine structure measurements revealed spectral features characteristics to the amorphous phase of calcium carbonate at 300 and 400°C. At 500 and 600°C, the spectra were analogues to the calcite phase of calcium carbonate. Simulation of extended X-ray absorption fine structure spectra envisaged that both coordination number and bond distance for Ca-O bonds decreased with annealing temperature. Both parameters attained values close to standard calcite when annealed at 600°C. The spectral features at Ca L-, O K- and C K-edge near edge X-ray absorption fine structure appeared at same positions for different ages, which envisaged the occurrence of almost same local electronic structure for different span of times.

Effects of biocementation on strength parameters of silty and clayey sands

Microbially induced calcite precipitation (MICP) is a bioinspired improvement method of granular soils, as it can significantly affect their engineering characteristics. In fact, calcite nanoparticles produced through MICP increase the angle of internal friction and cohesion intercept of granular soils. As a consequence, the shear strength values of granular soils are improved following the increase in these two parameters. However, MICP is not very efficient in strengthening fine-grained soils. In this study, using Sporosarcina pasteurii for MICP treatment, the effects of biocementation and plastic and non-plastic fines (clay and silt) on the shear strength parameters of sandy soils were investigated after 7, 10 and 15 d of treatment to analyse the viability of MICP in different sand mixtures in the field. Direct-shear tests, X-ray diffraction and scanning electron microscopy were used as investigative tools. The results obtained in this study showed that there was a significant improvement in the shear strength of the samples, while noticeable modification occurred within the first 7 d of treatment and fines reduced the MICP potential for strengthening of sandy soils. Although MICP boosted the cohesion intercept and the angle of internal friction of the samples, a great amount of the gained strength was due to cohesion growth.