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Dong, Y., Ji, X., Laaksonen, A., Cao, W., An, R., Lu, L. & Lu, X. (2019). Determination of the small amount of proteins interacting with TiO2 nanotubes by AFM-measurement. Biomaterials, 192, 368-376
Open this publication in new window or tab >>Determination of the small amount of proteins interacting with TiO2 nanotubes by AFM-measurement
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2019 (English)In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 192, p. 368-376Article in journal (Refereed) Published
Abstract [en]

Detecting the small amounts of proteins interacting effectively with the solid film electrodes surface still remains a challenge. To address this, in this work, a new approach was proposed by the combination of the adhesion forces and the molecular interaction measured with AFM. Cytochrome c (Cyt C) interacting effectively with TiO2 nanotube arrays (TNAs) was chosen as a probe. The amounts of Cyt C molecules interacting effectively on TNAs surface (CTNA) range from 5.5×10-12 to 7.0×10-12 mol/cm2 (68.2-86.8 ng/cm2) and they are comparable with the values obtained by the electrochemistry method in the literature, in evidence of the accuracy of this AFM-based approach. The reliability of the proposed approach was further verified by conducting Surface Enhanced Raman Scattering (SERS) measurements and estimating the enhancement factor (EF). This interaction-based AFM approach can be used to accurately obtain the small amounts of adsorbed substances on the solid film electrodes surface in the applications such as biosensors, biocatalysis, and drug delivery, etc.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
TiO2, nanotubes, Adsorption amount, AFM, Molecular interaction, Adhesion force, SERS
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-71860 (URN)10.1016/j.biomaterials.2018.11.013 (DOI)000456902000030 ()30476718 (PubMedID)2-s2.0-85059333773 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-12-03 (johcin)

Available from: 2018-12-03 Created: 2018-12-03 Last updated: 2019-02-22Bibliographically approved
Ma, C., Liu, C., Lu, X. & Ji, X. (2019). Erratum: Techno-economic analysis and performance comparison of aqueous deep eutectic solvent and other physical absorbents for biogas upgrading [Letter to the editor]. Applied Energy, 235, 1669-1670
Open this publication in new window or tab >>Erratum: Techno-economic analysis and performance comparison of aqueous deep eutectic solvent and other physical absorbents for biogas upgrading
2019 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 235, p. 1669-1670Article in journal, Letter (Refereed) Published
Abstract [en]

The authors regret to inform that there are errors in the vertical axis of Figs. 4 and 5 as well as corresponding text. The corrected versions are given below. (Figure presented.) Fig. 4b: the left y-axis should read “$·Nm-3 CH4” instead of “k$·Nm-3 CH4”; The corrected version of Fig. 5 is shown below. Abstract: The text at the end of Abstract: ‘For the case with …respectively’ should read: “…with AQ50wt.%DESand PC decrease by…” instead of “…with PC and AQ50wt.%DES decrease by…” Section 3.3.2: The text at the end of paragraph 5: ‘The results of specific TAC of using…than that using water, respectively. ’ should read: “…using AQ50wt.%DES and PC decrease by ….” instead of “…using PC and AQDES decrease by…” “…using AQ50wt.%DES and PC increase up to…” instead of “…using PC and AQ50wt.%DESincrease up to…” The text at the end of paragraph 6: ‘While, using…raw biogas capacity. ’ should read: “…and 25% than water…” instead of “…and 50% than water…” Conclusion: The text at the end of paragraph 2: ‘The results of specific TAC of using PC …than PC should be developed.’ should read: “…using AQ50wt.%DES and PC decrease by…” instead of “…using PC and AQ50wt.%DES decrease by…” “…using AQ50wt.%DES and PC treated with…” instead of “…using PC and AQ50wt.%DES treated with…” The above errors do not reflect any calculations errors and do not compromise the findings of the paper. The authors would like to apologize for any inconvenience caused. 

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-72798 (URN)10.1016/j.apenergy.2018.09.218 (DOI)2-s2.0-85060587157 (Scopus ID)
Note

Erratum in: Energy, Vol. 225, s. 437-447, DOI: 10.1016/j.apenergy.2018.04.112

Available from: 2019-02-06 Created: 2019-02-06 Last updated: 2019-02-06Bibliographically approved
Li, Z., Ji, X., Yang, Z. & Lu, X. (2019). Experimental studies of air-blast atomization on the CO2 capture with aqueous alkali solutions. Chinese Journal of Chemical Engineering
Open this publication in new window or tab >>Experimental studies of air-blast atomization on the CO2 capture with aqueous alkali solutions
2019 (English)In: Chinese Journal of Chemical Engineering, ISSN 1004-9541, E-ISSN 2210-321XArticle in journal (Refereed) Epub ahead of print
Abstract [en]

In this work, an air-blast atomizing column was used to study the CO2 capture performance with aqueous MEA (mono-ethanol-amine) and NaOH solutions. The effects of gas flow rate, the liquid to gas ratio (L/G), the CO2 concentration on the CO2 removal efficiency (η) and the volumetric overall mass transfer coefficient (KGav) were investigated. The air-blast atomizing column was also compared with the pressure spray tower on the studies of the CO2 capture performance. For the aqueous MEA and NaOH solutions, the experimental results show that the ηdecreases with increasing gas flow rate and CO2 concentration while it increases with increasing L/G. The effects on KGav are more complicated than those for η. When the CO2 concentration is low (3 v/v%), KGav increases with increasing gas flow rate while decreases with increasing L/G. However, when the CO2 concentration is high (9.5 v/v%), as the gas flow rate and L/G increases, KGav increases first and then decreases. The aqueous MEA solution achieves higher η and KGav than the aqueous NaOH solution. The air-blast atomizing column shows a good performance on CO2 capture.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Air-blast atomizer, CO2 capture, Aqueous alkali solutions
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-73068 (URN)10.1016/j.cjche.2019.01.021 (DOI)
Available from: 2019-02-28 Created: 2019-02-28 Last updated: 2019-02-28
Li, Z., Ji, X., Yang, Z. & Lu, X. (2019). Study of CO2 absorption/desorption behaviors in aqueous (2-hydroxyethyl)-trimethyl-ammonium (S)-2-pyrrolidine-carboxylic acid salt ([Cho][Pro]) + K2CO3 solutions. International Journal of Greenhouse Gas Control, 83, 51-60
Open this publication in new window or tab >>Study of CO2 absorption/desorption behaviors in aqueous (2-hydroxyethyl)-trimethyl-ammonium (S)-2-pyrrolidine-carboxylic acid salt ([Cho][Pro]) + K2CO3 solutions
2019 (English)In: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 83, p. 51-60Article in journal (Refereed) Published
Abstract [en]

In this work, an aqueous (2-hydroxyethyl)-trimethyl-ammonium (S)-2-pyrrolidinecarboxylic acid salt ([Cho][Pro]) + K2CO3 solution was studied as a novel absorbent for CO2 capture, and the kinetics and mechanism of the CO2 absorption/desorption process were systematically investigated. Adding [Cho][Pro] to the aqueous K2CO3 solution improved the absorption rate of the solution during the initial stage, and the apparent CO2 absorption rate increased as the concentration of [Cho][Pro] increased. Meanwhile, equilibrium was reached faster when [Cho][Pro] was added, and a tradeoff was noticed between the apparent absorption rate constant and equilibrium absorption amount. The desorption rates of the CO2-rich aqueous [Cho][Pro] + K2CO3 solutions were higher than that of the aqueous [Cho][Pro] solution at 363.15 K, and the highest apparent desorption rate constant was achieved for the aqueous 20 wt.% [Cho][Pro] + 10 wt.% K2CO3 solution. A further study on the aqueous 20 wt.% [Cho][Pro] + 10 wt.% K2CO3 solution indicated that the desorption amount increased with the increase in the temperature from 348.15 to 365.15 K. Moreover, with further increase in temperature, the desorption amount exhibited a lower increasing rate when temperature was higher than 361.15 K. The 20 wt.% [Cho][Pro] + 10 wt.% K2CO3 absorbent exhibited more stable regeneration performance after 7 cycles and lower desorption activation energy than the aqueous 30 wt.% monoethanolamine (MEA) and 30 wt.% [Cho][Pro] solutions as well as higher working capacity compared to the aqueous 30 wt.% [Cho][Pro] solution.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
CO2 capture, K2CO3, Aqueous ionic liquid
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-72902 (URN)10.1016/j.ijggc.2019.01.026 (DOI)2-s2.0-85061079546 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-02-15 (svasva)

Available from: 2019-02-15 Created: 2019-02-15 Last updated: 2019-02-15Bibliographically approved
Liu, Y., Chen, J., Song, J., Hai, Z., Lu, X., Ji, X. & Wang, C. (2018). Adjusting the rheological properties of corn-straw slurry to reduce the agitation power consumption in anaerobic digestion. Bioresource Technology, 272, 360-369
Open this publication in new window or tab >>Adjusting the rheological properties of corn-straw slurry to reduce the agitation power consumption in anaerobic digestion
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2018 (English)In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 272, p. 360-369Article in journal (Refereed) Published
Abstract [en]

Agitation power consumption (P) in the anaerobic digestion of biogas plants is a major consumer of electric energy. To reduce P by adjusting the rheological properties, in this work, the rheological properties of the corn-straw slurry were studied systematically considering the effects of TS, temperature and particle-size, and P was calculated based on the rheological behavior of the corn-straw slurry. The investigation shows that the corn-straw slurry is a non-Newtonian fluid and exhibit shear-thinning behavior, and the rheological properties can be well described with the power law model. The size-reduction is more effective compared to the option of temperature-increase to improve the agitation power efficiency, and the value of P can be reduced by up to 48.11 %. Since the size-reduction can also increase the methane yield, the reduction of the particle-size is a promising option to save P, especially at relatively high TSs and for the thermophilic AD process.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Rheological properties, Corn-straw slurry, Agitation power consumption, Anaerobic digestion
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-71317 (URN)10.1016/j.biortech.2018.10.050 (DOI)000451625700046 ()30384211 (PubMedID)2-s2.0-85055572951 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-10-30 (svasva)

Available from: 2018-10-30 Created: 2018-10-30 Last updated: 2019-01-10Bibliographically approved
Carvalho, L., Furusjö, E., Ma, C., Ji, X., Lundgren, J., Hedlund, J., . . . Wetterlund, E. (2018). Alkali enhanced biomass gasification with in situ S capture and a novel syngas cleaning: Part 2: Techno-economic analysis. Energy, 165(Part B), 471-482
Open this publication in new window or tab >>Alkali enhanced biomass gasification with in situ S capture and a novel syngas cleaning: Part 2: Techno-economic analysis
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2018 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 165, no Part B, p. 471-482Article in journal (Refereed) Published
Abstract [en]

Previous research has shown that alkali addition has operational advantages in entrained flow biomass gasification and allows for capture of up to 90% of the biomass sulfur in the slag phase. The resultant low-sulfur content syngas can create new possibilities for syngas cleaning processes. The aim was to assess the techno-economic performance of biofuel production via gasification of alkali impregnated biomass using a novel gas cleaning systemcomprised of (i) entrained flow catalytic gasification with in situ sulfur removal, (ii) further sulfur removal using a zinc bed, (iii) tar removal using a carbon filter, and (iv) CO2 reductionwith zeolite membranes, in comparison to the expensive acid gas removal system (Rectisol technology). The results show that alkali impregnation increases methanol productionallowing for selling prices similar to biofuel production from non-impregnated biomass. It was concluded that the methanol production using the novel cleaning system is comparable to the Rectisol technology in terms of energy efficiency, while showing an economic advantagederived from a methanol selling price reduction of 2–6 €/MWh. The results showed a high level of robustness to changes related to prices and operation. Methanol selling prices could be further reduced by choosing low sulfur content feedstocks.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Biomass gasification, Catalysis, Entrained-flowBio-methanol, Techno-economic analysis
National Category
Energy Systems Energy Engineering Chemical Process Engineering
Research subject
Energy Engineering; Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-68206 (URN)10.1016/j.energy.2018.09.159 (DOI)000455171600039 ()2-s2.0-85056197830 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-12-03 (johcin)

Available from: 2018-04-05 Created: 2018-04-05 Last updated: 2019-01-25Bibliographically approved
Furusjö, E., Ma, C., Ji, X., Carvalho, L., Lundgren, J. & Wetterlund, E. (2018). Alkali enhanced biomass gasification with in situ S capture and novel syngas cleaning: Part 1: Gasifier performance. Energy, 157, 96-105
Open this publication in new window or tab >>Alkali enhanced biomass gasification with in situ S capture and novel syngas cleaning: Part 1: Gasifier performance
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2018 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 157, p. 96-105Article in journal (Refereed) Published
Abstract [en]

Previous research shows that alkali addition in entrained flow biomass gasification can increase char conversion and decrease tar and soot formation through catalysis. This paper investigates two other potential benefits of alkali addition: increased slag flowability and in situ sulfur capture.

Thermodynamic equilibrium calculations show that addition of 2–8% alkali catalyst to biomass completely changes the chemical domain of the gasifier slag phase to an alkali carbonate melt with low viscosity. This can increase feedstock flexibility and improve the operability of an entrained flow biomass gasification process. The alkali carbonate melt also leads to up to 90% sulfur capture through the formation of alkali sulfides. The resulting reduced syngas sulfur content can potentially simplify gas cleaning required for catalytic biofuel production.

Alkali catalyst recovery and recycling is a precondition for the economic feasibility of the proposed process and is effected through a wet quench. It is shown that the addition of Zn for sulfur precipitation in the alkali recovery loop enables the separation of S, Ca and Mg from the recycle. For high Si and Cl biomass feedstocks, an alternative separation technology for these elements may be required to avoid build-up.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Energy Systems Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-68753 (URN)10.1016/j.energy.2018.05.097 (DOI)000440876600010 ()2-s2.0-85048465146 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-06-25 (andbra)

Available from: 2018-05-16 Created: 2018-05-16 Last updated: 2018-08-30Bibliographically approved
Zhang, Y., Ji, X. & Lu, X. (2018). Choline-based deep eutectic solvents for CO2 separation: Review and thermodynamic analysis. Renewable & sustainable energy reviews, 97, 436-455
Open this publication in new window or tab >>Choline-based deep eutectic solvents for CO2 separation: Review and thermodynamic analysis
2018 (English)In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 97, p. 436-455Article in journal (Refereed) Published
Abstract [en]

CO2 separation plays an important role in energy saving and CO2 emission reduction, both of which are necessary to address the issue of global warming. Ionic liquids (ILs) have been proposed to be “green” solvents for CO2 separation. Unfortunately, the high cost, toxicity, and poor biodegradability of these compounds limit their large-scale application. Deep eutectic solvents (DESs) were recently considered a new type of IL with additional advantages in terms of cost, environmental impact, and synthesis. DESs based on choline salts (i.e., choline-based DESs) are promising candidates for CO2 separation. In this work, the microstructures, physicochemical properties, and water effect of choline-based DESs are surveyed and compared with those of conventional ILs. The properties of choline-based DESs are similar to those of conventional ILs, but research on the latter remains limited. Further study on the microstructures, properties, and separation performance of choline-based DESs considering dynamic factors must be carried out through experimental measurements and model development. Thermodynamic analysis based on Gibbs free energy change is conducted to investigate the performances of choline-based-DESs during CO2 separation from biogas. Choline-based-DESs are screened on the basis of energy use and amount of absorbent needed. The performances of the screened choline-based-DESs are further compared with those of conventional ILs screened in our previous work, as well as commercial CO2 absorbents. Comparisons indicate that the screened DES-based absorbents show great application potential due to their nonvolatility, low energy use, or low amount required. The performances of physical choline-based-DES and 30 wt% MEA for CO2 separation from other gas streams (e.g., flue gas, lime kiln gas, and bio-syngas) are discussed. Considering the high amounts of physical absorbents required to enable separation, further study with techno-economic analysis needs to be carried out.

National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-70991 (URN)10.1016/j.rser.2018.08.007 (DOI)000448248600032 ()2-s2.0-85053406191 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-09-26 (inah)

Available from: 2018-09-26 Created: 2018-09-26 Last updated: 2018-11-15Bibliographically approved
Shen, G., Laaksonen, A., Lu, X. & Ji, X. (2018). Developing Electrolyte Perturbed-Chain Statistical Associating Fluid Theory Density Functional Theory for CO2 Separation by Confined Ionic Liquids. The Journal of Physical Chemistry C, 122(27), 15464-15473
Open this publication in new window or tab >>Developing Electrolyte Perturbed-Chain Statistical Associating Fluid Theory Density Functional Theory for CO2 Separation by Confined Ionic Liquids
2018 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, no 27, p. 15464-15473Article in journal (Refereed) Published
Abstract [en]

The electrolyte perturbed-chain statistical associating fluid theory (ePC-SAFT) classical density functional theory (DFT) was developed to describe the behavior of pure ionic liquid (IL) and CO2/IL mixture confined in nanopores, in which a new ionic functional based on the ionic term from ePC-SAFT was proposed for electrostatic free-energy contribution. The developed model was verified by comparing the model prediction with molecular simulation results for ionic fluids, and the agreement shows that the model is reliable in representing the confined behavior of ionic fluids. The developed model was further used to study the behavior of pure IL and CO2/IL mixture in silica nanopores where the IL ions and CO2 were modeled as chains that consisted of spherical segments with the parameters taken from the bulk ePC-SAFT. The results reveal that the nanoconfinement can lead to an increased CO2 solubility, and the solubility increases with increasing pressure. The averaged density of pure IL and solubility of CO2 are strongly dependent on pore sizes and geometries. In addition, the choice of IL ions is very important for the CO2 solubility. Overall, the modeling results for silica-confined systems are consistent with available molecular simulation and experimental results.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-70296 (URN)10.1021/acs.jpcc.8b04120 (DOI)000439003600046 ()
Note

Validerad;2018;Nivå 2;2018-08-09 (andbra)

Available from: 2018-08-09 Created: 2018-08-09 Last updated: 2018-08-09Bibliographically approved
Gao, Q., Zhu, Y., Ji, X., Zhu, W., Lu, L. & Lu, X. (2018). Effect of water concentration on the microstructures of choline chloride/urea (1:2) /water mixture. Fluid Phase Equilibria, 470, 134-139
Open this publication in new window or tab >>Effect of water concentration on the microstructures of choline chloride/urea (1:2) /water mixture
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2018 (English)In: Fluid Phase Equilibria, ISSN 0378-3812, E-ISSN 1879-0224, Vol. 470, p. 134-139Article in journal (Refereed) Published
Abstract [en]

Molecular dynamics was utilized to investigate the properties of ChCl/urea (1:2)/water mixtures from pure ChCl/urea to infinitely dilute solution. To further study the mechanism at molecular scale, the local microstructure variation in the mixtures with the increase of water content was analyzed in detail. Simulation results showed that neither choline cations nor chloride anions are saturated by the coordinated water molecules, even when the water molar fraction reaches 0.9. The hydration number proportions for different ions indicated that the hydration strength of chloride anion is stronger than that of choline cation, which may play greater effects on the properties of mixtures. This result is further confirmed by the analysis of interaction energy between cation (anion) and water molecules. Moreover, the ion pairing between choline cations and chloride anions is a dominant factor to affect the solution properties at lower water content, whereas the hydration turns to be the dominant factor with increasing water content. The competition between ion pairing and ionic hydration could be the intrinsic mechanism resulting in non-ideal properties.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-67531 (URN)10.1016/j.fluid.2018.01.031 (DOI)000437818000015 ()2-s2.0-85041349082 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-06-25 (andbra)

Available from: 2018-02-06 Created: 2018-02-06 Last updated: 2018-07-23Bibliographically approved
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