{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,11]],"date-time":"2026-01-11T02:20:36Z","timestamp":1768098036966,"version":"3.49.0"},"reference-count":43,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2025,7,17]],"date-time":"2025-07-17T00:00:00Z","timestamp":1752710400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Research Start-up Fund Project of Shandong Institute of Petroleum and Chemical Technology","award":["2023SS017"],"award-info":[{"award-number":["2023SS017"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Enhanced oil recovery (EOR) via CO2 flooding is a promising strategy for improving hydrocarbon recovery and carbon sequestration, yet the influence of pH on solid\u2013liquid interfacial interactions in quartz-dominated reservoirs remains poorly understood. This study employs molecular dynamics (MD) simulations to investigate the pH-dependent adsorption behavior of crude oil components on quartz surfaces and its impact on CO2 displacement mechanisms. Three quartz surface models with varying ionization degrees (0%, 9%, 18%, corresponding to pH 2\u20134, 5\u20137, and 7\u20139) were constructed to simulate different pH environments. The MD results reveal that aromatic hydrocarbons exhibit significantly stronger adsorption on quartz surfaces at high pH, with their maximum adsorption peak increasing from 398 kg\/m3 (pH 2\u20134) to 778 kg\/m3 (pH 7\u20139), while their alkane adsorption peaks decrease from 764 kg\/m3 to 460 kg\/m3. This pH-dependent behavior is attributed to enhanced cation\u2013\u03c0 interactions that are facilitated by Na+ ion aggregation on negatively charged quartz surfaces at high pH, which form stable tetrahedral configurations with aromatic molecules and surface oxygen ions. During CO2 displacement, an adsorption\u2013stripping\u2013displacement mechanism was observed: CO2 first forms an adsorption layer on the quartz surface, then penetrates the oil phase to induce the detachment of crude oil components, which are subsequently displaced by pressure. Although high pH enhances the Na+-mediated weakening of oil-surface interactions, which leads to a 37% higher diffusion coefficient (8.5 \u00d7 10\u22125 cm2\/s vs. 6.2 \u00d7 10\u22125 cm2\/s at low pH), the tighter packing of aromatic molecules at high pH slows down the displacement rate. This study provides molecular-level insights into pH-regulated adsorption and CO2 displacement processes, highlighting the critical role of the surface charge and cation\u2013\u03c0 interactions in optimizing CO2-EOR strategies for quartz-rich reservoirs.<\/jats:p>","DOI":"10.3390\/molecules30142999","type":"journal-article","created":{"date-parts":[[2025,7,17]],"date-time":"2025-07-17T10:33:47Z","timestamp":1752748427000},"page":"2999","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Mechanistic Study of Oil Adsorption Behavior and CO2 Displacement Mechanism Under Different pH Conditions"],"prefix":"10.3390","volume":"30","author":[{"given":"Xinwang","family":"Song","sequence":"first","affiliation":[{"name":"Shandong Key Laboratory of Green Electricity & Hydrogen Science and Technology, School of Chemical Engineering, Shandong Institute of Petroleum and Chemical Technology, Dongying 257061, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3589-1160","authenticated-orcid":false,"given":"Yang","family":"Guo","sequence":"additional","affiliation":[{"name":"Shandong Key Laboratory of Green Electricity & Hydrogen Science and Technology, School of Chemical Engineering, Shandong Institute of Petroleum and Chemical Technology, Dongying 257061, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yanchang","family":"Chen","sequence":"additional","affiliation":[{"name":"Shandong Key Laboratory of Green Electricity & Hydrogen Science and Technology, School of Chemical Engineering, Shandong Institute of Petroleum and Chemical Technology, Dongying 257061, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shiling","family":"Yuan","sequence":"additional","affiliation":[{"name":"Shandong Key Laboratory of Green Electricity & Hydrogen Science and Technology, School of Chemical Engineering, Shandong Institute of Petroleum and Chemical Technology, Dongying 257061, China"},{"name":"School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"130292","DOI":"10.1016\/j.cej.2021.130292","article-title":"Molecular insights into carbon dioxide enhanced multi-component shale gas recovery and its sequestration in realistic kerogen","volume":"425","author":"Wang","year":"2021","journal-title":"Chem. Eng. J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1016\/j.neures.2020.06.004","article-title":"Pim1 kinase provides protection against high glucose-induced stress and apoptosis in cultured dorsal root ganglion neurons","volume":"169","author":"Liu","year":"2021","journal-title":"Neurosci. Res."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"612","DOI":"10.1016\/j.jngse.2016.01.041","article-title":"Nanopores to megafractures: Current challenges and methods for shale gas reservoir and hydraulic fracture characterization","volume":"31","author":"Clarkson","year":"2016","journal-title":"J. Nat. Gas Sci. Eng."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"135060","DOI":"10.1016\/j.fuel.2025.135060","article-title":"A review of chemical methods and testing techniques for enhanced oil recovery in shale reservoirs","volume":"394","author":"Dordzie","year":"2025","journal-title":"Fuel"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"106174","DOI":"10.1016\/j.petrol.2019.06.038","article-title":"A comparative study of CO2 and N2 huff-n-puff EOR performance in shale oil production","volume":"181","author":"Li","year":"2019","journal-title":"J. Pet. Sci. Eng."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"145","DOI":"10.1016\/j.fuel.2016.11.041","article-title":"Experimental and numerical evaluation of CO2 huff-n-puff processes in Bakken formation","volume":"190","author":"Song","year":"2017","journal-title":"Fuel"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"28857","DOI":"10.1039\/C9RA05347F","article-title":"Experimental investigation of shale oil recovery from Qianjiang core samples by the CO2 huff-n-puff EOR method","volume":"9","author":"Li","year":"2019","journal-title":"RSC Adv."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"119583","DOI":"10.1016\/j.ijheatmasstransfer.2020.119583","article-title":"Static and dynamic behavior of CO2 enhanced oil recovery in nanoslits: Effects of mineral type and oil components","volume":"153","author":"Fang","year":"2020","journal-title":"Int. J. Heat Mass Transf."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"6949","DOI":"10.1038\/ncomms7949","article-title":"Subcontinuum mass transport of condensed hydrocarbons in nanoporous media","volume":"6","author":"Falk","year":"2015","journal-title":"Nat. Commun."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"11890","DOI":"10.1038\/ncomms11890","article-title":"Activated desorption at heterogeneous interfaces and long-time kinetics of hydrocarbon recovery from nanoporous media","volume":"7","author":"Lee","year":"2016","journal-title":"Nat. Commun."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"135978","DOI":"10.1016\/j.colsurfa.2024.135978","article-title":"Molecular simulation of quartz wetting in crude oil\/brine system at reservoir conditions using a novel protocol for contact angle calculation","volume":"708","author":"Khovental","year":"2025","journal-title":"Colloids Surf. A Physicochem. Eng. Asp."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"213640","DOI":"10.1016\/j.geoen.2024.213640","article-title":"Molecular insights into CO2 enhanced oil recovery and CO2 storage in quartz nanopores","volume":"246","author":"Li","year":"2025","journal-title":"Geoenergy Sci. Eng."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"105011","DOI":"10.1016\/j.earscirev.2024.105011","article-title":"Quartz types, formation mechanism, and its effect on shale oil and gas enrichment: A review","volume":"261","author":"Nie","year":"2025","journal-title":"Earth-Sci. Rev."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"134418","DOI":"10.1016\/j.colsurfa.2024.134418","article-title":"Solvent-responsive switching wettability of superoleophobic\/superhydrophilic quartz sand filter medium facilitates rapidly oil\/water separation and demulsification","volume":"697","author":"Zhang","year":"2024","journal-title":"Colloids Surf. A Physicochem. Eng. Asp."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"127032","DOI":"10.1016\/j.molliq.2025.127032","article-title":"Effects of mineral type on competitive adsorption and miscibility of CO2-oil system in tight reservoirs: A molecular dynamics study","volume":"423","author":"Qu","year":"2025","journal-title":"J. Mol. Liq."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"126865","DOI":"10.1016\/j.molliq.2025.126865","article-title":"The critical role of temperature on the CO2 replacement characteristics within inorganic minerals in shale oil reservoirs","volume":"421","author":"Tang","year":"2025","journal-title":"J. Mol. Liq."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"110818","DOI":"10.1016\/j.jece.2023.110818","article-title":"pH-regulated superhydrophobic quartz sands for controllable oil-water separation","volume":"11","author":"Lin","year":"2023","journal-title":"J. Environ. Chem. Eng."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"213766","DOI":"10.1016\/j.geoen.2025.213766","article-title":"Quantitative macro and micro analysis on enhanced oil recovery (EOR) mechanisms of multi-component composite steam flooding (MCCSF) based on image recognition algorithm","volume":"249","author":"Hong","year":"2025","journal-title":"Geoenergy Sci. Eng."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"134985","DOI":"10.1016\/j.fuel.2025.134985","article-title":"Confined transport property of multi-polar mixed shale oil components induced by interfacial effects within kerogen nanopores","volume":"393","author":"Zhang","year":"2025","journal-title":"Fuel"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"157421","DOI":"10.1016\/j.cej.2024.157421","article-title":"Dynamics of impure CO2 and composite oil in mineral nanopores: Implications for shale oil recovery and gas storage performance","volume":"500","author":"Wang","year":"2024","journal-title":"Chem. Eng. J."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"170537","DOI":"10.1016\/j.scitotenv.2024.170537","article-title":"Insights into the pH-dependent interactions of sulfadiazine antibiotic with soil particle models","volume":"917","author":"Yuan","year":"2024","journal-title":"Sci. Total Environ."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2647","DOI":"10.1021\/cm500365c","article-title":"Force Field and a Surface Model Database for Silica to Simulate Interfacial Properties in Atomic Resolution","volume":"26","author":"Emami","year":"2014","journal-title":"Chem. Mater."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"15837","DOI":"10.1021\/acsami.9b22189","article-title":"Brine\u2013Oil Interfacial Tension Modeling: Assessment of Machine Learning Techniques Combined with Molecular Dynamics","volume":"12","author":"Kirch","year":"2020","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"123243","DOI":"10.1016\/j.molliq.2023.123243","article-title":"Promising combination of CO2 enhanced oil recovery and CO2 sequestration in calcite nanoslits: Insights from molecular dynamics simulations","volume":"391","author":"Xue","year":"2023","journal-title":"J. Mol. Liq."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"100394","DOI":"10.1016\/j.engeos.2025.100394","article-title":"Hybrid CO2 thermal system for post-steam heavy oil recovery: Insights from microscopic visualization experiments and molecular dynamics simulations","volume":"6","author":"Lu","year":"2025","journal-title":"Energy Geosci."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/j.fluid.2018.03.022","article-title":"Molecular dynamics study of interfacial properties in CO2 enhanced oil recovery","volume":"467","author":"Wang","year":"2018","journal-title":"Fluid Phase Equilibria"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"125593","DOI":"10.1016\/j.molliq.2024.125593","article-title":"Microscopic mechanism of enhancing shale oil recovery through CO2 flooding- insights from molecular dynamics simulations","volume":"410","author":"Liu","year":"2024","journal-title":"J. Mol. Liq."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"277","DOI":"10.1021\/acs.jpcb.8b09777","article-title":"Molecular Dynamics Simulation of Surfactant Flooding Driven Oil-Detachment in Nano-Silica Channels","volume":"123","author":"Tang","year":"2019","journal-title":"J. Phys. Chem. B"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2667","DOI":"10.1021\/acs.jpcc.5b09841","article-title":"Molecular Dynamics Simulation of the Oil Detachment Process within Silica Nanopores","volume":"120","author":"Yan","year":"2016","journal-title":"J. Phys. Chem. C"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"5020","DOI":"10.1021\/acs.jpcc.6b11763","article-title":"Adsorption of a Polyaromatic Compound on Silica Surfaces from Organic Solvents Studied by Molecular Dynamics Simulation and AFM Imaging","volume":"121","author":"Xiong","year":"2017","journal-title":"J. Phys. Chem. C"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"6244","DOI":"10.1021\/ja211307u","article-title":"Chemistry of Aqueous Silica Nanoparticle Surfaces and the Mechanism of Selective Peptide Adsorption","volume":"134","author":"Patwardhan","year":"2012","journal-title":"J. Am. Chem. Soc."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"8540","DOI":"10.1021\/acs.energyfuels.4c06408","article-title":"A Molecular Simulation Study on Selective Adsorption of CO2 from an Industrial Ternary Gas Mixture inside Porous Silica and Kaolinite Adsorbents","volume":"39","author":"Kumar","year":"2025","journal-title":"Energy Fuels"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"10251","DOI":"10.1021\/acsaem.4c00376","article-title":"Molecular Insights into Effects of Methanol Additive on CO2 Enhanced Oil Recovery in the Dead-End Nanopore","volume":"7","author":"Zhang","year":"2024","journal-title":"ACS Appl. Energy Mater."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"7558","DOI":"10.1021\/acs.energyfuels.2c01547","article-title":"Supercritical CO2 Breaking Through a Water Bridge and Enhancing Shale Oil Recovery: A Molecular Dynamics Simulation Study","volume":"36","author":"Liu","year":"2022","journal-title":"Energy Fuels"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"978","DOI":"10.1021\/acs.est.4c10047","article-title":"Molecular Mechanisms of Humic Acid in Inhibiting Silica Scaling during Membrane Distillation","volume":"59","author":"Yuan","year":"2025","journal-title":"Environ. Sci. Technol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"18281","DOI":"10.1021\/ja107519d","article-title":"Self-Accumulation of Aromatics at the Oil\u2212Water Interface through Weak Hydrogen Bonding","volume":"132","author":"Kunieda","year":"2010","journal-title":"J. Am. Chem. Soc."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"643","DOI":"10.1016\/j.ijheatmasstransfer.2019.06.083","article-title":"Molecular insight into the miscible mechanism of CO2\/C10 in bulk phase and nanoslits","volume":"141","author":"Fang","year":"2019","journal-title":"Int. J. Heat Mass Transf."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1016\/j.fuel.2016.11.019","article-title":"Enhanced oil recovery mechanism of CO2 water-alternating-gas injection in silica nanochannel","volume":"190","author":"Yan","year":"2017","journal-title":"Fuel"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1306\/13391706M1023584","article-title":"Pore Size Distribution and Morphology in the Horn River Shale, Middle and Upper Devonian, Northeastern British Columbia, Canada","volume":"102","author":"Dong","year":"2013","journal-title":"Electron Microsc. Shale Hydrocarb. Reserv."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1157","DOI":"10.1002\/jcc.20035","article-title":"Development and testing of a general amber force field","volume":"25","author":"Wang","year":"2004","journal-title":"J. Comput. Chem."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"014101","DOI":"10.1063\/1.2408420","article-title":"Canonical sampling through velocity rescaling","volume":"126","author":"Bussi","year":"2007","journal-title":"J. Chem. Phys."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1463","DOI":"10.1002\/(SICI)1096-987X(199709)18:12<1463::AID-JCC4>3.0.CO;2-H","article-title":"LINCS: A linear constraint solver for molecular simulations","volume":"18","author":"Hess","year":"1997","journal-title":"J. Comput. Chem."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1016\/0263-7855(96)00018-5","article-title":"VMD: Visual molecular dynamics","volume":"14","author":"Humphrey","year":"1996","journal-title":"J. Mol. Graph."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/30\/14\/2999\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:11:07Z","timestamp":1760033467000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/30\/14\/2999"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,7,17]]},"references-count":43,"journal-issue":{"issue":"14","published-online":{"date-parts":[[2025,7]]}},"alternative-id":["molecules30142999"],"URL":"https:\/\/doi.org\/10.3390\/molecules30142999","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,7,17]]}}}