ACS ES&T engineeringPub Date : 2026-10-09Epub Date: 2026-09-07DOI: 10.1021/acsestengg.6c00279
Ruizhe Xu, Weiliang Bai, Aida Fica, Mircea Podar, Han Gu, Jana Safarik, Julio A. Polanco, Cynthia M. Swift, Megan H. Plumlee, Frank E. Löffler, Pedro J. J. Alvarez, Manish Kumar
{"title":"Microbial Community Dynamics in Full-Scale Water Reuse Reverse Osmosis System Revealed by Longitudinal Monitoring Using Membrane Fouling Simulators","authors":"Ruizhe Xu, Weiliang Bai, Aida Fica, Mircea Podar, Han Gu, Jana Safarik, Julio A. Polanco, Cynthia M. Swift, Megan H. Plumlee, Frank E. Löffler, Pedro J. J. Alvarez, Manish Kumar","doi":"10.1021/acsestengg.6c00279","DOIUrl":"https://doi.org/10.1021/acsestengg.6c00279","url":null,"abstract":"<p>Membrane fouling, especially biofouling,hinders theefficiencyof reverse osmosis (RO) membranes in water reuse, leading to higherenergy consumption and operating costs. Understanding biofilm microbialcommunity composition and dynamics is critical to developing biofoulingmitigation strategies, but the need to sacrifice membrane moduleshas restricted the progress and scale-up of such research. In thisstudy, membrane fouling simulators (MFSs) were adopted as an innovative,nondisruptive technique for temporal sampling and monitoring of RObiofilms, providing a reliable proxy for the dominant taxa that colonizefull-scale RO membranes. Microbial communities in the MFSs graduallystabilized, becoming highly similar across sampling points between6 months and 1 year of operation and matching samples from full-scalemodules operated over the 1-year period. Three dominant taxa wereidentified: <em>Mycobacterium</em> (biofilm-forming, disinfection-resistantbacteria), <em>Rickettsiales AB1</em> (parasitic bacteria),and <em>Nitrosomonas</em> (ammonia oxidizers), whose abundancescorrelated with water quality parameters, including temperature, ammonianitrogen, and total chlorine. Co-occurrence network analysis of theMFS biofilm microbiome revealed two apparent microbial clusters: onecentered around <em>Mycobacterium</em> and other taxa associatedwith extracellular polymeric substance (EPS) production and a secondcluster composed of parasitic and ammonia-oxidizing bacteria thatformed a separate ecological niche with weak connections to the EPS-producinggroup. These results highlight how MFSs can provide informative andfrequent insight into RO biofilm structure and dynamics that, if furthercorrelated with full-scale studies, may eliminate the need to sacrificefull-scale membrane elements.</p>","PeriodicalId":7008,"journal":{"name":"ACS ES&T engineering","volume":"6 10","pages":"2813–2823"},"PeriodicalIF":6.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS ES&T engineeringPub Date : 2026-10-09Epub Date: 2026-09-07DOI: 10.1021/acsestengg.6c00400
Francesca Angelini, Michela Sbicego, Agata Gallipoli, Stefania Angelini, Barbara Tonanzi, Barbara Casentini, Camilla Maria Braguglia, Andrea Gianico
{"title":"Thermal Hydrolysis-Driven Lactate Enrichment and Caproate Specificity in Self-Buffered Mixed Waste Fermentation: Mechanistic Insights into a Long-Term Integrated Chain Elongation and Anaerobic Digestion Process","authors":"Francesca Angelini, Michela Sbicego, Agata Gallipoli, Stefania Angelini, Barbara Tonanzi, Barbara Casentini, Camilla Maria Braguglia, Andrea Gianico","doi":"10.1021/acsestengg.6c00400","DOIUrl":"https://doi.org/10.1021/acsestengg.6c00400","url":null,"abstract":"<p>This study demonstratesa sustainable continuous productionofmedium-chain fatty acids (MCFAs) from real waste streams, achievingstable caproate synthesis without external buffering or electron donoraddition. This new process couples microbial chain elongation of mixedfood waste (FW) and waste activated sludge (WAS) with downstream anaerobicdigestion (AD), using thermal hydrolysis (TH) of WAS as a key enablingstep. Both acidogenic reactors─one fed with FW + WAS<sub>raw</sub> and one with FW + WAS<sub>TH</sub>─exhibited high and stableperformance, with acidification degrees of 79–84% and totalfatty acid (C<sub>2</sub>–C<sub>8</sub>) concentrations of12 ± 1 gCOD L<sup>–1</sup>. Notably, the TH-assisted systemachieved a consistent and selective caproate (C<sub>6</sub>) productionof 4.7 ± 0.5 gCOD L<sup>–1</sup> with 24% higher productivitycompared to the untreated condition. Process robustness was ensuredunder unbuffered conditions, with tight pH control (5.1–5.3)mitigating undissociated C<sub>6</sub> toxicity and supporting long-termstability. High-frequency monitoring revealed a rapid substrate turnoverwith a dynamic lactate-driven metabolism, where endogenous lactatesustained efficient transition to elongation, enabling continuouscarbon flux toward MCFAs. Coupling the system with AD ensured completevalorization of fermentation residues, achieving methane yields of0.43 ± 0.02 Nm<sup>3</sup> kg<sup>–1</sup> VS<sub>broth</sub> and stable operation despite the short HRT of 15 days. Metals trackingshowed that heavy metals remained largely confined to the solid phase,while Mn, Na, K, Ca, Mg, and P, mobilized during fermentation, re-precipitatedduring AD, resulting in a nutrient-rich, agriculturally safe digestate.Overall, this work demonstrates a robust, self-sustaining, and scalableplatform for urban biowaste valorization through integrated MCFAsproduction and biomethane recovery.</p>","PeriodicalId":7008,"journal":{"name":"ACS ES&T engineering","volume":"6 10","pages":"2870–2885"},"PeriodicalIF":6.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS ES&T engineeringPub Date : 2026-10-09Epub Date: 2026-09-10DOI: 10.1021/acsestengg.6c00367
Jennifer N. Jocz, Sarah R. Suffield, Sundaram Bhardwaj Ramakrishnan, Qingpu Wang, Peter J. Valdez, Chinmayee V. Subban
{"title":"Scale-Up of Laminar Coflow Method for Selective Precipitation from Micro- to Millifluidics","authors":"Jennifer N. Jocz, Sarah R. Suffield, Sundaram Bhardwaj Ramakrishnan, Qingpu Wang, Peter J. Valdez, Chinmayee V. Subban","doi":"10.1021/acsestengg.6c00367","DOIUrl":"https://doi.org/10.1021/acsestengg.6c00367","url":null,"abstract":"<p>The laminar coflow method (LCM) is a promising separationapproachthat allows selective precipitation of minerals from complex feedstocks.LCM offers unique process control, leading to high product purityand selectivity, but the method is in early stages of research withreported studies currently limited to experiments in microfluidicdevices at low flow rates. Commercial implementation of LCM for criticalmineral separation will require the scale-up of coflow reactors througha combination of numbering-up and scaling-up to meet the flow ratesrequired for industrial-scale processing. In this study, we experimentallyevaluated LCM scale-up using the selective precipitation of Mg(OH)<sub>2</sub> from seawater as a representative chemistry. We successfullydemonstrated the feasibility of scaling-up LCM from microfluidic devicesto the millifluidic scale without performance loss and provided thefirst demonstration of continuous solid collection using LCM. We usedcomputational fluid dynamics (CFD) modeling to identify the criticalscalability parameters. Our CFD model outputs showed alignment withexperimental observations and that the steep concentration gradientscharacteristic of LCM can be achieved in reactors up to 1 m in diameter.The model also identified a <5% difference in fluid densities asa design limitation for maintaining a well-defined reactive interfacefor LCM. To be industrially relevant, LCM will need further scale-upfrom millifluidics, and this is the first step toward designing largerLCM reactors.</p>","PeriodicalId":7008,"journal":{"name":"ACS ES&T engineering","volume":"6 10","pages":"2859–2869"},"PeriodicalIF":6.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Understanding Mass Transport and Reaction Environment to Optimize CO2 Electrodialysis Systems","authors":"Jintong Gao, Yusaku Nishimura, Gong Zhang, Tsuyoshi Hamaguchi, Masaoki Iwasaki, Lenan Zhang","doi":"10.1021/acsestengg.6c00435","DOIUrl":"https://doi.org/10.1021/acsestengg.6c00435","url":null,"abstract":"<p>Electrodialysis(ED) is a critical technology for decarbonization,which can be paired with direct air capture to produce a concentratedCO<sub>2</sub> stream for efficient carbon utilization and storage.Although previous studies have significantly advanced CO<sub>2</sub> ED at the process, membrane, and system levels, the coupled masstransport and reaction environment governing CO<sub>2</sub> regenerationremain insufficiently understood, limiting further improvement incurrent efficiency. Here we develop a spatially resolved modelingframework for CO<sub>2</sub> ED. Our approach captures the interplayamong concentration polarization, pH gradient, and reaction localization,thereby enabling direct prediction of CO<sub>2</sub> generation rate,proton utilization efficiency, and bubble nucleation barrier. Usingthree representative electrolytes with distinct acid–base properties,we show that buffering and acidity can substantially reshape ion distributionsand reaction zones, which produce electrolyte-specific trade-offsbetween CO<sub>2</sub> regeneration and bubble nucleation. Buildingon these mechanistic insights, we further identify ED cell geometriesand operating conditions that maximize proton utilization efficiencywhile mitigating undesirable bubble nucleation. This work elucidatesmass transport and reaction environment in CO<sub>2</sub> ED, providingtransport-informed design insights for efficient CO<sub>2</sub> regenerationpowered by renewable electricity.</p>","PeriodicalId":7008,"journal":{"name":"ACS ES&T engineering","volume":"6 10","pages":"2908–2921"},"PeriodicalIF":6.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS ES&T engineeringPub Date : 2026-10-09Epub Date: 2026-08-31DOI: 10.1021/acsestengg.6c00470
Yu Gan, Branden E. Leonhardt, Jacob G. Englander, Hao Cai, Michael Wang
{"title":"Life Cycle Greenhouse Gas Emissions Analysis of Wastewater Sludge Management Practices in the United States","authors":"Yu Gan, Branden E. Leonhardt, Jacob G. Englander, Hao Cai, Michael Wang","doi":"10.1021/acsestengg.6c00470","DOIUrl":"https://doi.org/10.1021/acsestengg.6c00470","url":null,"abstract":"<p>Publicly owned treatment works in the United States generatemorethan 12 million dry tonnes of wastewater sludge annually, underscoringthe need to evaluate current management practices, emissions burden,and sludge-to-energy potential. In this work, we developed a first-of-its-kindfacility-level database tracing ∼75% of the national wastewatersludge flow from treatment through disposal and used R&D GREETto quantify life-cycle greenhouse gas (GHG) emissions for 25 pathwayswith Monte Carlo uncertainty analysis. Emissions vary widely: landfillinguntreated or limed sludge is the most GHG-intensive pathway (2,030kg CO<sub>2</sub>e dry t<sup>–1</sup>), driven by methane releaseduring decomposition, while several pathways ending in land application,including composting plus land application (34 kg CO<sub>2</sub>edry t<sup>–1</sup>), thermal drying plus land application (110kg CO<sub>2</sub>e dry t<sup>–1</sup>), and anaerobic digestionwith combined heat and power plus digestate land application (−71kg CO<sub>2</sub>e dry t<sup>–1</sup>), exhibit markedly loweremissions. Some pathways achieve net-negative emissions through soilcarbon sequestration, electricity export, and fertilizer displacement.This study establishes standardized business-as-usual counterfactualsfor life-cycle analyses of sludge-derived fuels, identifies key driverssuch as landfill gas capture and flaring, soil carbon sequestration,and methane emissions from digestate management, and highlights theGHG mitigation potential of improved sludge management.</p>","PeriodicalId":7008,"journal":{"name":"ACS ES&T engineering","volume":"6 10","pages":"2947–2960"},"PeriodicalIF":6.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS ES&T engineeringPub Date : 2026-10-09Epub Date: 2026-09-09DOI: 10.1021/acsestengg.6c00440
Brayan D. Riascos, Bumkyu Kim, Steven D. Karlen, Jason Coplien, Dennis V. Haak, Sarada Sripada, Canan Sener, Timothy J. Donohue, K.G. Karthikeyan, Daniel R. Noguera
{"title":"Postanaerobic Digestion Manure Fibers as a Renewable Source of Lignin-Derived Aromatic Compounds for Microbial Upgrading","authors":"Brayan D. Riascos, Bumkyu Kim, Steven D. Karlen, Jason Coplien, Dennis V. Haak, Sarada Sripada, Canan Sener, Timothy J. Donohue, K.G. Karthikeyan, Daniel R. Noguera","doi":"10.1021/acsestengg.6c00440","DOIUrl":"https://doi.org/10.1021/acsestengg.6c00440","url":null,"abstract":"<p>Postanaerobic digestion manure fibers are an abundantsolid residuethat remains underutilized. The substantial lignocellulosic contentof digested manure opens the possibility of using it as a renewableresource for producing valuable products. In this study, we performedcompositional and nuclear magnetic resonance analyses to determinelignin content and aromatic composition of these fibers. Additionally,alkaline-based treatment and reductive catalytic fractionation wereevaluated as two different processes to produce aromatic-rich streams.The liquor from the alkaline treatment was subsequently utilized formicrobial upgrading to produce 2-pyrone-4,6-dicarboxylic acid (PDC).The results showed that lignin in manure fibers represents 30% ofthe biomass (dry weight basis), with a ∼26% abundance of β-ether-linkedaromatics and ∼13% <em>p</em>-coumarate moieties, indicatingthat the amount of lignin in the postanaerobic biomass is comparableto a moderately pretreated plant biomass. The alkaline treatment released5.6 g aromatics/kg fibers, while reductive catalytic fractionationproduced 14.0 g aromatics/kg fibers. A bioreactor operated in fed-batchmode produced a yield of ∼1 mol of PDC/mol measured aromaticsat a rate of 0.2 g PDC/L·h and a titer of 2.6 g PDC/L. This studydemonstrates how postanaerobic digestion manure fibers could be usedin a circular bioeconomy by harnessing their lignocellulosic contentto extract aromatic compounds and use them for obtaining valuablechemicals via microbial upgrading.</p>","PeriodicalId":7008,"journal":{"name":"ACS ES&T engineering","volume":"6 10","pages":"2922–2932"},"PeriodicalIF":6.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS ES&T engineeringPub Date : 2026-10-09Epub Date: 2026-09-08DOI: 10.1021/acsestengg.6c00413
Srikanth V, Bhanu Prakash Vellanki
{"title":"Insights into the Microbial Community Dynamics during Seeding and Its Role in Developing Biological Activated Carbon Filter for Simultaneous Biodegradation of Organics, Nitrogen, and Emerging Contaminants from Secondary Effluent","authors":"Srikanth V, Bhanu Prakash Vellanki","doi":"10.1021/acsestengg.6c00413","DOIUrl":"https://doi.org/10.1021/acsestengg.6c00413","url":null,"abstract":"<p>The study evaluates seeding granular activated carbon(GAC) withsewage and sludge inocula to understand the dynamics of the microbialcommunity over 25 days and to optimize the duration of seeding forbeneficial biofilm formation on GAC. The study also evaluates theimpact of seeding duration on conversion of GAC into biological activatedcarbon (BAC), attainment of steady-state conditions, and simultaneousdegradation of organics, nitrogen, and emerging contaminants (ECs).A 7-day seeding successfully kick-starts bacterial activity, introducingheterotrophs as well as pathogens, and exhibits a low abundance ofnitrifiers and denitrifiers. At 14 days, a balanced community of heterotrophs,nitrifiers, and denitrifiers was found. At 21 days, microbes responsiblefor producing extracellular polymeric substances (EPS) were found,which are crucial for bacterial adhesion and biofilm formation whilemaintaining a balanced microbiome. The columns loaded with 25 days(BAC-25) and 7 days (BAC-7) seeded BAC reached a steady state at 2881(30 days) and 4801 (50 days) bed volumes (BVs), respectively, whilethe control reached 20,166 BVs (210 days). BAC-25 showed a reductionin dissolved organic carbon (DOC) by 80% (<2 mg/L), meeting theUSEPA DOC recommendation for drinking water, whereas earlier studiesreported <50% reduction. NH<sub>4</sub>–N and NO<sub>3</sub>–N were lowered from 2.3 to 0.75 mg/L and 6.3 to 2.6 mg/L,respectively. Fourteen of 17 ECs were removed by >80%, at an EBCTof 15 min, while BAC-7 and control achieved only 8 and 4 ECs with>80% removal, respectively. Higher protein content in EPS improvedelectron transfer, which is positively correlated with the detectionof more transformation products and a higher abundance of functionalgenes encoding enzymes likely involved in the degradation of ECs.Over time, pathogens were also eliminated from the BAC biofilm dueto competitive disadvantage. Overall, seeding expedited the conversionof GAC into BAC, with enhanced microbial diversity and functionalroles.</p>","PeriodicalId":7008,"journal":{"name":"ACS ES&T engineering","volume":"6 10","pages":"2886–2907"},"PeriodicalIF":6.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS ES&T engineeringPub Date : 2026-10-09Epub Date: 2026-08-29DOI: 10.1021/acsestengg.6c00283
Bhavana Kanwar, Amritanshu Shriwastav, Lokesh P. Padhye, Swatantra P. Singh
{"title":"Electrochemical Degradation of PFOA Using Graphite-Sheet Electrodes: Kinetics and Mechanisms","authors":"Bhavana Kanwar, Amritanshu Shriwastav, Lokesh P. Padhye, Swatantra P. Singh","doi":"10.1021/acsestengg.6c00283","DOIUrl":"https://doi.org/10.1021/acsestengg.6c00283","url":null,"abstract":"<p>Per- and polyfluoroalkyl substances (PFAS) are persistent,bioaccumulative,and toxic contaminants characterized by highly stable fluorinatedalkyl chains. Due to their chemical resilience, PFAS are frequentlydetected in both influents and effluents of conventional wastewatertreatment plants, where they undergo minimal to no removal. Electrooxidationoffers a promising, chemical-free approach for PFAS remediation, butit typically relies on expensive, high-performance electrodes suchas boron-doped diamond (BDD) or titanium-based materials, limitingscalability and practical deployment. This study establishes the useof low-cost, unmodified, flexible graphite sheet electrodes as anodesfor the electrochemical degradation of perfluorooctanoic acid (PFOA).The degradation efficiency was assessed under varying conditions,including initial PFOA concentrations (5–1,000 μg·L<sup>–1</sup>), current densities (2.5–12.5 mA.cm<sup>–2</sup>), pH (3–9), electrolyte concentrations (0–0.05 M NaCl),and the presence of reactive radical species. Under optimized conditions(0.05 M NaCl, 10 mA.cm<sup>–2</sup>, pH ≈ 6), ∼99%PFOA degradation was achieved within 90 min at an initial concentrationof 10 μg·L<sup>–1</sup>, with a corresponding energyconsumption of 16.09 kWh.m<sup>–3</sup> per order. Hydroxylradicals and chlorine-based reactive species were identified as keycontributors to the degradation mechanism. However, degradation efficiencywas inhibited in the presence of a complex wastewater matrix, consistentwith the known limitations of radical-mediated processes. Liquid chromatography–massspectrometry (LC-MS) analysis of the 90 min sample revealed the formationof intermediate degradation products, including shorter-chain perfluoroalkylcarboxylic acids such as perfluoroheptanoic acid (PFHpA), perfluorohexanoicacid (PFHxA), perfluoropentanoic acid (PFPeA), and perfluorobutanoicacid (PFBA). Overall, the electrochemical oxidation approach demonstratedin this study offers a promising, economically attractive alternativefor the degradation of PFAS in contaminated groundwater and wastewater.</p>","PeriodicalId":7008,"journal":{"name":"ACS ES&T engineering","volume":"6 10","pages":"2824–2835"},"PeriodicalIF":6.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS ES&T engineeringPub Date : 2026-10-09Epub Date: 2026-09-08DOI: 10.1021/acsestengg.6c00526
Dongxin Yao, Kangwei Yin, Piaopiao Wei, Xianhao Gao, Peng Zhang, Jie Yu, Xuanhao Wu, Zhongbiao Wu, Hailu Fu
{"title":"Tailoring the D-Band Center of Sol-Gel-Derived Nd-Doped NiO for Ultra-Low-Temperature N2O Decomposition with Improved Impurity Resistance","authors":"Dongxin Yao, Kangwei Yin, Piaopiao Wei, Xianhao Gao, Peng Zhang, Jie Yu, Xuanhao Wu, Zhongbiao Wu, Hailu Fu","doi":"10.1021/acsestengg.6c00526","DOIUrl":"https://doi.org/10.1021/acsestengg.6c00526","url":null,"abstract":"<p>Mitigating the profound environmental impact of greenhousegasnitrous oxide (N<sub>2</sub>O) emissions necessitates the design ofhighly active, low-temperature, and impurity-tolerant decompositioncatalysts. In this work, sol-gel-derived neodymium-incorporated nickeloxide (Nd<sub><em>x</em></sub>Ni) catalysts were systematicallydeveloped for direct N<sub>2</sub>O decomposition. The optimal Nd<sub>0.06</sub>Ni achieves 90% N<sub>2</sub>O conversion (T<sub>90</sub>) at a remarkably low temperature of 275 °C. Compared to bareNiO, it exhibits a drastically suppressed apparent activation energy(<em>E</em><sub><em>a</em></sub>) declining from 97.15to 61.31 kJ/mol, and a 1.5-fold increase in turnover frequency (TOF).In the individual presence of NO, O<sub>2</sub>, or H<sub>2</sub>O,Nd<sub>0.06</sub>Ni exhibited improved impurity resistance relativeto pristine NiO, maintaining T<sub>90</sub> values within 315–360°C. However, simultaneous exposure to the three impurities substantiallysuppressed the N<sub>2</sub>O conversion, whereas the activity largelyrecovered after the impurities were removed, indicating reversibleinhibition under the present conditions. Crucially, density functionaltheory (DFT) calculations, underpinned by d-band center analysis,reveal the intrinsic catalytic mechanism: Nd incorporation shiftsthe d-band center of surface Ni sites downward from −2.41 eVto −2.56 eV. This moderate electronic modulation optimallyweakens the over-strong Ni–O bond, substantially reducing theenergy required for O<sub>2</sub> desorption (from 5.19 to 4.58 eV)and thus accelerating the Ni<sup>2+</sup>/Ni<sup>3+</sup> redox cycle.This work provides fundamental insights and a viable strategy fordesigning ultra-low-temperature catalysts with improved impurity resistancefor practical N<sub>2</sub>O abatement.</p>","PeriodicalId":7008,"journal":{"name":"ACS ES&T engineering","volume":"6 10","pages":"2992–3002"},"PeriodicalIF":6.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149124795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}