Investigating molecular conformation and packing of oxidized asphaltene molecules in presence of paraffin wax

Samieadel, Alireza; Oldham, Daniel; Fini, Elham H.

doi:10.1016/j.fuel.2018.02.031

Cited by 41 publications

(36 citation statements)

References 34 publications

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“…Some of these observations/conclusions have been demonstrated by other research groups as well (Dutta Majumdar et al 2017;Headen et al 2017;Samieadel et al 2018;Biktagirov et al 2017). In any case, the rational and consistent modification of the asphaltenes molecular structures and the conditions to which they are submitted to allow us to establish the structure-function link we intend to determine.…”

Section: Introductionmentioning

confidence: 57%

Asphaltene aggregation studied by molecular dynamics simulations: role of the molecular architecture and solvents on the supramolecular or colloidal behavior

et al. 2019

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Asphaltene aggregation is a subject under vivid discussion: There are several parameters one needs to determine before its behavior can be mastered and better target solutions can be tailored. The nature of asphaltene aggregation (colloidal or supramolecular) and the role of solvents and their mixtures are among the least understood parameters in asphaltene science. This paper addresses molecular dynamic simulations to correlate the aggregation properties of asphaltenes, their molecular structure and the concentration of these solvents. We show that the formation of the nanoaggregate depends, primarily, on the size of the conjugated core and on the eventual presence of polar groups capable of forming H-bonds. Heteroatoms on the conjugated core do not change their shape or type of aggregation but may induce stronger π − π interactions. The macroaggregation formation depends upon the length of the lateral chains of asphaltenes and also on the presence of polar groups at its end. Moreover, n-heptane and water may interact selectively with asphaltenes in function of their molecular architecture. Given this fact and the aggregation behavior observed, we advocate toward the assumption that a colloidal behavior of asphaltenes might be a particular case of a more general model, based on a supramolecular description.

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Section: Introductionmentioning

confidence: 57%

Asphaltene aggregation studied by molecular dynamics simulations: role of the molecular architecture and solvents on the supramolecular or colloidal behavior

et al. 2019

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“…To facilitate comparing studied scenarios, the sum of the two indexes was calculated at each aging interval and referred to as the chemical aging index (CAI), following the method used by other researchers. 28 − 30 The asphalt sample without biochar showed a CAI of 22% after 50 h and 40% after 200 h of aging ( Table 7 ). Among all asphalt samples with biochar, the sample containing algal biochar (100–0 scenario) had the lowest CAI value of 17% after 50 h and 26% after 200 h of aging.…”

Section: Resultsmentioning

confidence: 99%

“…When asphalt samples were exposed to UV aging, their carbonyl index and sulfoxide index increased, with the largest increase happening in the first 50 h. Asphalt samples without biochar showed a higher increasing rate than asphalt samples with biochar. To facilitate comparing studied scenarios, the sum of the two indexes was calculated at each aging interval and referred to as the chemical aging index (CAI), following the method used by other researchers. − The asphalt sample without biochar showed a CAI of 22% after 50 h and 40% after 200 h of aging (Table ). Among all asphalt samples with biochar, the sample containing algal biochar (100–0 scenario) had the lowest CAI value of 17% after 50 h and 26% after 200 h of aging.…”

Section: Resultsmentioning

confidence: 99%

“…It should be noted that the crossover values (frequencies at which storage modulus and loss modulus are equal) are reported to be reliable measures to track changes in the polydispersity of bitumen . Considering that progressive aging leads to significant changes in polydispersity as asphaltene molecules forms nanoaggregates, , crossover values are deemed appropriate to not only track the evolution of bitumen during aging but also rejuvenation . Provided the crossover frequency and corresponding crossover moduli are measured at the same temperature for all bitumen specimens in comparison, the crossover values can properly detect and compare the extent of aging and in this study extent of delay in aging. in which where γ max = maximum strain, τ max = maximum stress, T = maximum applied torque, r = radius of the sample, θ = deflection (rotational) angle, and h = height of the sample.…”

Section: Experiments Planmentioning

confidence: 99%

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Inherently Functionalized Carbon from Lipid and Protein-Rich Biomass to Reduce Ultraviolet-Induced Damages in Bituminous Materials

Rajib

Fini

2020

ACS Omega

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This paper examines the merits of using an inherently functionalized carbon, referred to as biochar as a free radical scavenger. The biochar was made from thermochemical liquefaction of a blend of algae (rich in protein and nucleic acids) and manure (rich in lipid). Here, we studied biochar’s efficacy as a free-radical scavenger and ultraviolet blocker to qualify it as an anti-aging additive in construction, including roofing shingles made from the bituminous composite. The study’s results show that the addition of biochar to bitumen significantly reduced the aging of bitumen. All tested biochars made from various relative proportions of algae and swine manure were found to be effective at reducing the extent of aging; however, the biochar made from algae alone was the most effective. The algal biochar was found to be an effective antiaging additive delaying aging up to 36%, as evidenced by lower rheology and the chemistry-based aging index compared to those of control bitumen after being exposed to the same aging protocol. Algal biochar was found to be more effective than other studied biochar scenarios owing to its inherently functionalized nature. The latter result could be attributed to the high surface area and rich phenol functional groups in algal biochar, turning it into an effective free-radical scavenger. The study outcome highlights the applicability of this inherently functionalized carbon referred to as biochar in construction to enhance sustainability while promoting the circular economy and the biomass value chain.

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“… 2 − 4 Due to the introduction of polar functional groups in asphaltene molecules, the polar binding forces such as hydrogen bond, van der Waals force, and Coulomb interaction increase, resulting in further molecular agglomeration and the formation of nano-aggregates. 5 − 7 The nano-aggregation has been implicated in the undesirable high stiffness and brittleness of aged asphalt binder. 8 …”

Section: Introductionmentioning

confidence: 99%

Research on the Ability of Bio-rejuvenators to Disaggregate Oxidized Asphaltene Nanoclusters in Aged Asphalt

Zheng

et al. 2022

ACS Omega

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A real rejuvenator must have the ability to disaggregate oxidized asphaltene nanoclusters. However, few studies pay attention to the topic, and there is a lack of comparison of the disaggregation ability of different rejuvenators. Thus, the disaggregation ability and regeneration mechanism of three bio-rejuvenators (waste cooking oil (WCO), waste wood oil (WWO), and straw liquefied residue oil (SLRO)) on oxidized asphaltene nanoclusters were studied in this paper. Laboratory tests and molecular dynamics (MD) simulation were used to compare the effectiveness of the three bio-rejuvenators and reveal its corresponding mechanism. It is found that these bio-rejuvenators have a softening effect on aged asphalt binder, but not all of them can disaggregate oxidized asphaltene nanoclusters. The introduction of WWO and WCO can effectively disturb the nanoclusters caused by the increase of polar functional groups during the oxidation process. The effect of WWO is more significant, but neither of them can restore the asphaltene dispersion to the virgin asphalt binder. SLRO has an adverse effect on the disaggregation of oxidized asphaltene nanoclusters. WCO, WWO, and SLRO showed different disaggregation mechanisms, including ″pull-out, intercalation, and compression″, respectively. WCO and WWO can increase the activation energy reduced by aging in a short aging time, and SLRO makes the activation energy lower. Such findings can help enterprises screen more reasonable rejuvenators to facilitate the recycling of reclaimed asphalt pavement (RAP) materials and promote the sustainable development of the construction industry.

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Investigating molecular conformation and packing of oxidized asphaltene molecules in presence of paraffin wax

Cited by 41 publications

References 34 publications

Asphaltene aggregation studied by molecular dynamics simulations: role of the molecular architecture and solvents on the supramolecular or colloidal behavior

Asphaltene aggregation studied by molecular dynamics simulations: role of the molecular architecture and solvents on the supramolecular or colloidal behavior

Inherently Functionalized Carbon from Lipid and Protein-Rich Biomass to Reduce Ultraviolet-Induced Damages in Bituminous Materials

Research on the Ability of Bio-rejuvenators to Disaggregate Oxidized Asphaltene Nanoclusters in Aged Asphalt

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