Conventional in-situ light non-aqueous phase liquid (LNAPL) remediation techniques often face challenges of high costs and limited efficiency, leaving residual hydrocarbons trapped in soil pores. This study investigates the efficiency of an alcohol-in-biopolymer emulsion for enhancing diesel-contaminated soil remediation. The emulsion, formulated with xanthan gum biopolymer, sodium dodecyl sulfate surfactant, and the oil-soluble alcohol 1-pentanol, was evaluated through rheological tests, interfacial tension measurements, and onedimensional sand-column experiments under direct injection and post-waterflooding scenarios. The emulsion exhibited non-Newtonian shear-thinning behavior with high viscosity, ensuring stable propagation and efficient delivery of 1-pentanol to mobilize trapped diesel ganglia. It achieved 100 % diesel recovery within 1.2 PV during direct injection, outperforming shear-thinning polymer-only and polymer-surfactant solutions, which achieved recovery factors of 83.4-92.9 %. Post-waterflooding experiments also demonstrated 100 % diesel recovery within 1.3 PV, regardless of initial diesel saturation. Key mechanisms include reduced interfacial tension, diesel swelling and mobilization induced by 1-pentanol, and uniform displacement facilitated by the emulsion's viscosity. Additionally, the emulsion required lower injection pressures compared to more viscous alternatives, enhancing its injectability into the soil and reducing energy demands. These findings highlight the emulsion's potential to overcome conventional remediation limitations, offering a highly effective and sustainable solution for diesel-contaminated soils and groundwater.
Expansive clay soil is known to cause damage to pavements due to its volume fluctuations with changes in moisture content, a phenomenon observed globally in many countries. Implementing suitable stabilisation treatments is crucial for improving the mechanical and hydraulic properties of the expansive clay subgrade. While cement and lime have traditionally been widely used as soil stabilisers, there is a growing emphasis on sustainable engineering due to increased awareness of global warming. Seeking alternative green and sustainable materials for soil stabilisation is demanded now, and one such alternative is using ethylene-vinyl acetate (EVA) copolymer emulsion. However, the use of EVA copolymer emulsion for stabilising expansive clay has been relatively underexplored in existing studies. This study evaluates the feasibility of utilising EVA copolymer emulsion for stabilising expansive clay subgrade through comprehensive laboratory tests to assess the mechanical (compaction, unconfined compressive strength, California bearing ratio, resilient modulus, and direct shear), hydraulic (soil-water retention curve and swellshrinkage), and micro-chemical (thermogravimetric analyses and scanning electron microscopic) performance of the soil. The experimental results indicate that the inclusion of 1 % EVA copolymer emulsion into the expansive clay provided the highest mechanical properties, resulting in an increase in the unconfined compressive strength, soaked California bearing ratio, resilient modulus, and cohesion by 8.8 %, 177.8 %, 35.8 % and 19.4 %, respectively. Swell-shrinkage behaviour was also improved with the addition of EVA copolymer, with 1 % EVA copolymer presenting the lowest swell-shrinkage index of 3.19 %/pF (14 % decrease in shrink-swell potential compared to the untreated clay).
Conventional pump-and-treat technologies have demonstrated limited effectiveness in remediating soils contaminated with light non-aqueous phase liquids (LNAPLs), such as petroleum hydrocarbons. Nonconventional in-situ flushing with shear-thinning fluids, such as polymers, offers a promising alternative. However, even with polymer flushing, residual LNAPL ganglia may remain trapped in porous media, requiring further improvement of the flushing fluid to enhance remediation efficiency. In this study, we present a novel alcohol-in-biopolymer emulsion developed to enhance the recovery of residual diesel oil from porous media. Batch experiments were conducted to evaluate the partitioning behavior of fifteen different alcohols between the aqueous and diesel phases. The results revealed that 1-pentanol preferentially partitions into the diesel phase rather than the aqueous phase, leading to an increase in diesel oil volume via a swelling mechanism. Furthermore, 1-pentanol forms a stable and homogeneous emulsion when combined with an aqueous solution of the biopolymer xanthan gum, and the surfactant sodium dodecyl sulfate. The emulsion demonstrated high stability for over 30 days, ensuring its suitability for prolonged remediation processes. Rheological experiments confirmed the emulsion's shear-thinning behavior, which ensures stable and uniform displacement within porous media. A two-dimensional cell packed with silica sand was used to evaluate the efficiency of the emulsion in removing residual diesel oil. The results demonstrated that the emulsion propagates uniformly throughout the porous media, effectively achieving complete removal of residual diesel within 1.15 pore volumes of injection. Porescale visualizations revealed the swelling and subsequent mobilization of entrapped diesel ganglia induced by the emulsion, further confirming its efficacy. These findings highlight the potential of this novel alcohol-inbiopolymer emulsion to significantly improve diesel oil recovery from contaminated soils.
The pervasive use of petroleum-based food packaging has caused significant ecological damage due to their unsustainability and non-biodegradability. Polysaccharide-based biodegradable materials are promising alternatives, but low hydrophobicity and functional properties limit their practical applications which can be overcome by incorporation of phytochemical(s). Therefore, by leveraging the strong antioxidant and antibacterial potential of pterostilbene (PTB), we have developed PTB nanoemulsion (NE) incorporated chitosan/sodium alginate (CS/SA) film for food packaging applications. The PTBNE was prepared by high pressure homogenization and characterized for particle size distribution and morphology via DLS, TEM and AFM. The PTBNE CS/SA film was developed by solvent casting method and demonstrated improved mechanical, optical, water resistance and oxygen barrier properties as compared to native CS/SA film. The films were characterized via SEM, 3D optical profilometry, FTIR, XRD and TGA analysis to assess morphological and structural variations. Notably, incorporation of PTBNE in CS/SA matrix significantly enhanced the antioxidant and antibacterial potential of film along with biocompatibility in fibroblast cells. The developed PTBNE CS/SA film demonstrated comparable results with polythene in post harvested shiitake mushroom preservation up to 10 days with rapid soil degradation. Overall, the findings suggested that PTBNE CS/SA film can be a promising alternative to conventional petroleum-based packaging materials.
Chilled meat is prone to microbial contamination during storage, resulting in a shortened shelf life. This study developed multifunctional biodegradable aerogel with water absorption, antibacterial, and sustained release properties as a preservation pad for meat, using corn straw cellulose nanocrystals (CSCNCs) and acetylated starch (AS) as the structural skeleton and thymol (TMO) nanoemulsions as antimicrobials. The effects of different mass ratios of CSCNCs/AS on the morphology, structure, physical properties, and release behavior of aerogels were systematically analyzed. Additionally, their antibacterial properties, biocompatibility, and biodegradability were investigated. The results showed that the aerogels with CSCNC/AS mass ratio of 1:5 had a tailored structure for loading TMO nanoemulsions, as well as excellent water absorption, mechanical properties, and thermal stability. Due to strong hydrogen bonding and a porous structure, the TMO in the aerogels was continuously and uniformly released into high-water-activity and fatty food simulants, mainly controlled by Fickian diffusion. Furthermore, it exhibited superior antibacterial properties and biocompatibility. The application of aerogels for chilled beef preservation extended the shelf life from 8 days to approximately 12 days, which was superior to commercially available preservation pads. Notably, the aerogels exhibited superior biodegradability in soil. Therefore, the prepared aerogel preservation pads showed great potential in preserving chilled meat.
In order to investigate the mechanism of mechanical performance enhancement and the curing mechanisms of acrylate emulsion (AE) in cement and magnesium slag (MS) composite-stabilized soil (AE-C-M), this study has conducted a comprehensive analysis of the compressive strength and microstructural characteristics of AE-C-M stabilized soil. The results show that the addition of AE significantly improves the compressive strength of the stabilized soil. When the AE content is 0.4%, the cement content is 3%, and the magnesium slag content is 3% (AE4-C3M3), the strength of the formula reaches 4.21 MPa, which meets the requirements of heavy traffic load conditions in the construction of high-speed or main road base layers. Some reactive groups on the polymer side chains (-COOH) engage in bridging with Ca2+ and RCOO- to form a chemically bonded interpenetrating network structure, thereby enabling the acrylate emulsion to enhance the water damage resistance of the specimens. The notable improvement in strength is attributed to the film-forming and solidifying actions of AE, the binding and filling effects of C-S-H gel, and the reinforcing effect of straw fibers. FT-IR and TG-DSC analysis reveals the presence of polar electrostatic interactions between AE and the soil matrix. AE enhances the bonding among soil particles and facilitates the attachment of C-S-H gel onto the surfaces of the straw fibers, thereby increasing the strength and toughness of the material. The application of MS in conjunction with straw fibers within polymer-modified stabilized soil serves to promote the recycling of waste materials, thereby providing an environmentally friendly solution for the engineering application of solid waste.
The alarming issue of food waste, coupled with the potential risks posed by petroleum-based plastic preservation materials to both the environment and human health necessitate innovative solutions. In this study, we prepared nanoemulsions (NEs) of chitosan (CS) and ginger essential oil (GEO) and systematically evaluated the effects of varying NEs concentrations (0, 10 %, 30 %, 50 %) on the physicochemical properties and biological activities of gelatin films. These films were subsequently applied to blueberry preservation. The scanning electron microscopy confirmed that the NEs were well-integrated with the Gel matrix, significantly enhancing the performance of the Gel films, including improvements of mechanical properties (tensile strength from 7.71 to 19.92 MPa; elongation at break from 38.55 to 113.65 %), thermal, and barrier properties (water vapor permeability from 1.52 x 10(-9)to 6.54 x 10(-10) g & sdot;m/Pa & sdot;s & sdot;m(2)). The films exhibited notable antibacterial and antioxidant activities due to the gradual release of GEO, thereby extending the storage life of blueberries. Moreover, the prepared composite films demonstrated excellent biodegradability and environmental friendliness, with the majority of the material decomposing within 30 days under soil microbial action. In conclusion, the active films loaded with NEs exhibit superior performance and hold significant potential for developing biodegradable materials for food preservation.
Clay-based mortars are susceptible to water intake and exhibit low mechanical strength, presenting challenges in their application within the construction sector. This research addresses these vulnerabilities by investigating the combination of alkali activators with waterproofing agents, specifically a nano-clay and an acrylic emulsion, to enhance the properties of clay mortars. Alkali-activated materials are known for their superior mechanical properties and sustainable potential, especially when derived from low-cost by-products. Recent studies have focused on alkali activation using clays and soils as precursors to improve their physical and mechanical properties while increasing durability. However, the high absorbency of these mortars remains a concern, as it can lead to matrix degradation. Therefore, to address these problems, this research studied the combination of a highly alkaline activator (potassium metasilicate) with hydrophobic agents, such as a nano-clay and an acrylic emulsion, using two different clayey soils. The results indicated that potassium metasilicate (PO) enhanced the mechanical properties and stability for both aluminosilicate systems, while nano-clay (PONC) significantly reduced the capillary absorption through time, especially in A2 systems. The addition of acrylic emulsion (POD) proved highly effective in both systems, significantly improving durability. By integrating these agents, the mortar systems were protected against water intake, while durable construction materials were formed.
Mexico is the cradle of great ancient civilizations that promoted earth-based architecture (cob, mud-brick, structure fills). Nowadays, such earth-based materials are widely investigated to understand their composition, mechanical properties and its resistance to aging. The present study evaluates the effect of composition on flexural and impact properties as well as water absorption capabilities. Soil was used from pre-Columbian site of la Joya, in Mexico, to manufacture experimental mud-bricks emulating the ancient technique using cut grass and asphalt emulsions. It was found that mechanical stabilization and material cohesion are in function of the additive's nature. Flexural and impact strengths of samples were examined and results were correlated to damage mechanisms by using acoustic emission technique exhibiting the onset, propagation and fracture. Mechanical properties were found to be higher in samples with synthetic additives, compared to control samples.
The stabilization of asphalt pavement bases with granular soil and aggregates emulsified with asphalt is a widely used technique in road construction and maintenance. It aims to improve the mechanical properties and durability of the lower pavement layers. Currently, there is no consensus on the most suitable method for designing emulsified granular aggregates with reclaimed asphalt pavement (RAP), as it is very complex. Therefore, the methodology is generally based on compliance with one or more volumetric or mechanical parameters established in the highway regulations for conventional asphalt mixtures, which does not guarantee the optimization and characterization of the recycled mixture in the base course. In this study, granular mixtures were developed, including five with emulsion and one emulsion-free as a control mix. Granular RAP mixes were designed in this study, including five with emulsion and one emulsion-free as a control mix. The five mixes ranged from 1% to 5% emulsion and were characterized by multi-stage triaxial tests with repeated load resilient modulus (RM) and permanent deformation (PD) to evaluate their mechanical behavior. The results showed that the mixes had RM values between 350 and 500 MPa, consistent with literature values. However, they showed similar levels of accumulated deformation to the control mix without RAP emulsion. The sample with 1 % RAP emulsion exhibited a satisfactory RM value and better performance in PD than the control mix (5 mm) and showed accumulated PD values of up to 4 mm. In contrast, the other samples exhibited deformations of up to 6 mm. In this study, the multi-stagge triaxial RM and PD tests were found to be an effective predictive method for characterizing the behavior of RAP materials in base courses, regardless of the types of admixtures contained. Multi-stage resilient modulus and PD tests can be considered as a predictive method for the behavior of milled material in base courses. They were able to provide initial data for interpreting the behavior of ETB mixtures.