Skip to main content
Erschienen in: Journal of Materials Science 14/2018

23.04.2018 | Composites

Flexible electrospun MWCNTs/Ag3PO4/PAN ternary composite fiber membranes with enhanced photocatalytic activity and stability under visible-light irradiation

verfasst von: Xiao-Qiong Wu, Jiang-Shan Shen, Fei Zhao, Zai-Dong Shao, Lu-Bin Zhong, Yu-Ming Zheng

Erschienen in: Journal of Materials Science | Ausgabe 14/2018

Einloggen

Aktivieren Sie unsere intelligente Suche um passende Fachinhalte oder Patente zu finden.

search-config
loading …

Abstract

Semiconductor photocatalysis is a promising technology for removing contaminants from water. Particularly, visible-light photocatalysis has attracted much attention because of its potential to utilize solar energy. However, nano-sized visible-light-driven photocatalysts easily aggregate during water treatment. Besides, it is difficult to recycle them from treated systems. Therefore, it is of great importance to develop visible-light-responsive immobilized photocatalysts with high activity. In this work, MWCNTs/Ag3PO4/polyacrylonitrile (PAN) ternary composite fiber membranes (TCFMs) with good photocatalytic performance were fabricated by electrospinning technique combined with in situ Ag3PO4 forming reaction. Due to the addition of MWCNTs, the band gap of MWCNTs/Ag3PO4/PAN TCFMs became narrower than that of Ag3PO4/PAN binary composite fiber membranes (BCFMs), which made MWCNTs/Ag3PO4/PAN TCFMs be able to use light at longer wavelengths. Compared with Ag3PO4/PAN BCFMs, the as-prepared MWCNTs/Ag3PO4/PAN TCFMs showed enhanced photocatalytic activity and stability for degrading rhodamine B (RhB) in batch processing systems, which mainly ascribed to fast electron transfer from Ag3PO4 to MWCNTs and the resulting high electron–hole (e–h+) separation efficiency. Radical trapping experiments revealed that holes (h+) and superoxide radicals (·O2) played primary roles in RhB degradation. In addition, the flexible MWCNTs/Ag3PO4/PAN TCFMs also showed potential practical application in the continuous wastewater treatment by a suitable photocatalytic membrane reactor. This work provides a facile approach to prepare flexible supported photocatalytic membrane with visible-light response, high activity and good stability.

Sie haben noch keine Lizenz? Dann Informieren Sie sich jetzt über unsere Produkte:

Springer Professional "Wirtschaft+Technik"

Online-Abonnement

Mit Springer Professional "Wirtschaft+Technik" erhalten Sie Zugriff auf:

  • über 102.000 Bücher
  • über 537 Zeitschriften

aus folgenden Fachgebieten:

  • Automobil + Motoren
  • Bauwesen + Immobilien
  • Business IT + Informatik
  • Elektrotechnik + Elektronik
  • Energie + Nachhaltigkeit
  • Finance + Banking
  • Management + Führung
  • Marketing + Vertrieb
  • Maschinenbau + Werkstoffe
  • Versicherung + Risiko

Jetzt Wissensvorsprung sichern!

Springer Professional "Technik"

Online-Abonnement

Mit Springer Professional "Technik" erhalten Sie Zugriff auf:

  • über 67.000 Bücher
  • über 390 Zeitschriften

aus folgenden Fachgebieten:

  • Automobil + Motoren
  • Bauwesen + Immobilien
  • Business IT + Informatik
  • Elektrotechnik + Elektronik
  • Energie + Nachhaltigkeit
  • Maschinenbau + Werkstoffe




 

Jetzt Wissensvorsprung sichern!

Anhänge
Nur mit Berechtigung zugänglich
Literatur
1.
Zurück zum Zitat Ong W-J, Tan L-L, Ng YH, Yong S-T, Chai S-P (2016) Graphitic carbon nitride (g-C3N4)-based photocatalysts for artificial photosynthesis and environmental remediation: are we a step closer to achieving sustainability? Chem Rev 116:7159–7329CrossRef Ong W-J, Tan L-L, Ng YH, Yong S-T, Chai S-P (2016) Graphitic carbon nitride (g-C3N4)-based photocatalysts for artificial photosynthesis and environmental remediation: are we a step closer to achieving sustainability? Chem Rev 116:7159–7329CrossRef
2.
Zurück zum Zitat Mateo D, Esteve-Adell I, Albero J, Royo JFS, Primo A, Garcia H (2016) 111 oriented gold nanoplatelets on multilayer graphene as visible light photocatalyst for overall water splitting. Nat Commun 7:1–8CrossRef Mateo D, Esteve-Adell I, Albero J, Royo JFS, Primo A, Garcia H (2016) 111 oriented gold nanoplatelets on multilayer graphene as visible light photocatalyst for overall water splitting. Nat Commun 7:1–8CrossRef
3.
Zurück zum Zitat Zhao X, Qu J, Liu H, Hu C (2007) Photoelectrocatalytic degradation of triazine-containing azo dyes at γ-Bi2MoO6 film electrode under visible light irradiation (λ > 420 Nm). Environ Sci Technol 41:6802–6807CrossRef Zhao X, Qu J, Liu H, Hu C (2007) Photoelectrocatalytic degradation of triazine-containing azo dyes at γ-Bi2MoO6 film electrode under visible light irradiation (λ > 420 Nm). Environ Sci Technol 41:6802–6807CrossRef
4.
Zurück zum Zitat Li Y, Tang Z, Zhang J, Zhang Z (2016) Reduced graphene oxide three-dimensionally wrapped WO3 hierarchical nanostructures as high-performance solar photocatalytic materials. Appl Catal A Gen 522:90–100CrossRef Li Y, Tang Z, Zhang J, Zhang Z (2016) Reduced graphene oxide three-dimensionally wrapped WO3 hierarchical nanostructures as high-performance solar photocatalytic materials. Appl Catal A Gen 522:90–100CrossRef
5.
Zurück zum Zitat Yao W, Zhang B, Huang C, Ma C, Song X, Xu Q (2012) Synthesis and characterization of high efficiency and stable Ag3PO4/TiO2 visible light photocatalyst for the degradation of methylene blue and rhodamine B solutions. J Mater Chem 22:4050–4055CrossRef Yao W, Zhang B, Huang C, Ma C, Song X, Xu Q (2012) Synthesis and characterization of high efficiency and stable Ag3PO4/TiO2 visible light photocatalyst for the degradation of methylene blue and rhodamine B solutions. J Mater Chem 22:4050–4055CrossRef
6.
Zurück zum Zitat Lee KM, Lai CW, Ngai KS, Juan JC (2016) Recent developments of zinc oxide based photocatalyst in water treatment technology: a review. Water Res 88:428–448CrossRef Lee KM, Lai CW, Ngai KS, Juan JC (2016) Recent developments of zinc oxide based photocatalyst in water treatment technology: a review. Water Res 88:428–448CrossRef
7.
Zurück zum Zitat Liu B, Li Z, Xu S, Han D, Lu D (2014) Enhanced visible-light photocatalytic activities of Ag3PO4/MWCNT nanocomposites fabricated by facile in situ precipitation method. J Alloys Compd 596:19–24CrossRef Liu B, Li Z, Xu S, Han D, Lu D (2014) Enhanced visible-light photocatalytic activities of Ag3PO4/MWCNT nanocomposites fabricated by facile in situ precipitation method. J Alloys Compd 596:19–24CrossRef
8.
Zurück zum Zitat Martin DJ, Liu G, Moniz SJ, Bi Y, Beale AM, Ye J, Tang J (2015) Efficient visible driven photocatalyst, silver phosphate: performance, understanding and perspective. Chem Soc Rev 44:7808–7828CrossRef Martin DJ, Liu G, Moniz SJ, Bi Y, Beale AM, Ye J, Tang J (2015) Efficient visible driven photocatalyst, silver phosphate: performance, understanding and perspective. Chem Soc Rev 44:7808–7828CrossRef
9.
Zurück zum Zitat Yi Z, Ye J, Kikugawa N, Kako T, Ouyang S, Stuart-Williams H, Yang H, Cao J, Luo W, Li Z, Liu Y, Withers RL (2010) An orthophosphate semiconductor with photooxidation properties under visible-light irradiation. Nat Mater 9:559–564CrossRef Yi Z, Ye J, Kikugawa N, Kako T, Ouyang S, Stuart-Williams H, Yang H, Cao J, Luo W, Li Z, Liu Y, Withers RL (2010) An orthophosphate semiconductor with photooxidation properties under visible-light irradiation. Nat Mater 9:559–564CrossRef
10.
Zurück zum Zitat Chen Z, Wang W, Zhang Z, Fang X (2013) High-efficiency visible-light-driven Ag3PO4/AgI photocatalysts: Z-scheme photocatalytic mechanism for their enhanced photocatalytic activity. J Phys Chem C 117:19346–19352CrossRef Chen Z, Wang W, Zhang Z, Fang X (2013) High-efficiency visible-light-driven Ag3PO4/AgI photocatalysts: Z-scheme photocatalytic mechanism for their enhanced photocatalytic activity. J Phys Chem C 117:19346–19352CrossRef
11.
Zurück zum Zitat Teng W, Li X, Zhao Q, Chen G (2013) Fabrication of Ag/Ag3PO4/TiO2 heterostructure photoelectrodes for efficient decomposition of 2-chlorophenol under visible light irradiation. J Mater Chem A 1:9060–9068CrossRef Teng W, Li X, Zhao Q, Chen G (2013) Fabrication of Ag/Ag3PO4/TiO2 heterostructure photoelectrodes for efficient decomposition of 2-chlorophenol under visible light irradiation. J Mater Chem A 1:9060–9068CrossRef
12.
Zurück zum Zitat Chen X, Dai Y, Wang X (2015) Methods and mechanism for improvement of photocatalytic activity and stability of Ag3PO4: a review. J Alloys Compd 649:910–932CrossRef Chen X, Dai Y, Wang X (2015) Methods and mechanism for improvement of photocatalytic activity and stability of Ag3PO4: a review. J Alloys Compd 649:910–932CrossRef
13.
Zurück zum Zitat Bi Y, Hu H, Ouyang S, Jiao Z, Lu G, Ye J (2012) Selective growth of Ag3PO4 submicro-cubes on Ag nanowires to fabricate necklace-like heterostructures for photocatalytic applications. J Mater Chem 22:14847–14850CrossRef Bi Y, Hu H, Ouyang S, Jiao Z, Lu G, Ye J (2012) Selective growth of Ag3PO4 submicro-cubes on Ag nanowires to fabricate necklace-like heterostructures for photocatalytic applications. J Mater Chem 22:14847–14850CrossRef
14.
Zurück zum Zitat Hu H, Jiao Z, Wang T, Ye J, Lu G, Bi Y (2013) Enhanced photocatalytic activity of Ag/Ag3PO4 coaxial hetero-nanowires. J Mater Chem A 1:10612–10616CrossRef Hu H, Jiao Z, Wang T, Ye J, Lu G, Bi Y (2013) Enhanced photocatalytic activity of Ag/Ag3PO4 coaxial hetero-nanowires. J Mater Chem A 1:10612–10616CrossRef
15.
Zurück zum Zitat Peng W-C, Wang X, Li X-Y (2014) The synergetic effect of MoS2 and graphene on Ag3PO4 for its ultra-enhanced photocatalytic activity in phenol degradation under visible light. Nanoscale 6:8311–8317CrossRef Peng W-C, Wang X, Li X-Y (2014) The synergetic effect of MoS2 and graphene on Ag3PO4 for its ultra-enhanced photocatalytic activity in phenol degradation under visible light. Nanoscale 6:8311–8317CrossRef
16.
Zurück zum Zitat He Y, Zhang L, Teng B, Fan M (2015) New application of Z-scheme Ag3PO4/g-C3N4 composite in converting CO2 to fuel. Environ Sci Technol 49:649–656CrossRef He Y, Zhang L, Teng B, Fan M (2015) New application of Z-scheme Ag3PO4/g-C3N4 composite in converting CO2 to fuel. Environ Sci Technol 49:649–656CrossRef
17.
Zurück zum Zitat Bu Y, Chen Z (2014) Role of polyaniline on the photocatalytic degradation and stability performance of the polyaniline/silver/silver phosphate composite under visible light. ACS Appl Mater Interfaces 6:17589–17598CrossRef Bu Y, Chen Z (2014) Role of polyaniline on the photocatalytic degradation and stability performance of the polyaniline/silver/silver phosphate composite under visible light. ACS Appl Mater Interfaces 6:17589–17598CrossRef
18.
Zurück zum Zitat Tang C, Liu E, Wan J, Hu X, Fan J (2016) Co3O4 nanoparticles decorated Ag3PO4 tetrapods as an efficient visible-light-driven heterojunction photocatalyst. Appl Catal B Environ 181:707–715CrossRef Tang C, Liu E, Wan J, Hu X, Fan J (2016) Co3O4 nanoparticles decorated Ag3PO4 tetrapods as an efficient visible-light-driven heterojunction photocatalyst. Appl Catal B Environ 181:707–715CrossRef
19.
Zurück zum Zitat Katsumata H, Sakai T, Suzuki T, Kaneco S (2014) Highly efficient photocatalytic activity of g-C3N4/Ag3PO4 hybrid photocatalysts through Z-scheme photocatalytic mechanism under visible light. Ind Eng Chem Res 53:8018–8025CrossRef Katsumata H, Sakai T, Suzuki T, Kaneco S (2014) Highly efficient photocatalytic activity of g-C3N4/Ag3PO4 hybrid photocatalysts through Z-scheme photocatalytic mechanism under visible light. Ind Eng Chem Res 53:8018–8025CrossRef
21.
Zurück zum Zitat Xu L, Huang W-Q, Wang L-L, Huang G-F, Peng P (2014) Mechanism of superior visible-light photocatalytic cctivity and stability of hybrid Ag3PO4/graphene nanocomposite. J Phys Chem C 118:12972–12979CrossRef Xu L, Huang W-Q, Wang L-L, Huang G-F, Peng P (2014) Mechanism of superior visible-light photocatalytic cctivity and stability of hybrid Ag3PO4/graphene nanocomposite. J Phys Chem C 118:12972–12979CrossRef
22.
Zurück zum Zitat Yang X, Cui H, Li Y, Qin J, Zhang R, Tang H (2013) Fabrication of Ag3PO4-graphene composites with highly efficient and stable visible light photocatalytic performance. ACS Catal 3:363–369CrossRef Yang X, Cui H, Li Y, Qin J, Zhang R, Tang H (2013) Fabrication of Ag3PO4-graphene composites with highly efficient and stable visible light photocatalytic performance. ACS Catal 3:363–369CrossRef
23.
Zurück zum Zitat Zhang H, Huang H, Ming H, Li H, Zhang L, Liu Y, Kang Z (2012) Carbon quantum dots/Ag3PO4 complex photocatalysts with enhanced photocatalytic activity and stability under visible light. J Mater Chem 22:10501–10506CrossRef Zhang H, Huang H, Ming H, Li H, Zhang L, Liu Y, Kang Z (2012) Carbon quantum dots/Ag3PO4 complex photocatalysts with enhanced photocatalytic activity and stability under visible light. J Mater Chem 22:10501–10506CrossRef
24.
Zurück zum Zitat Xu H, Wang C, Song Y, Zhu J, Xu Y, Yan J, Song Y, Li H (2014) CNT/Ag3PO4 composites with highly enhanced visible light photocatalytic activity and stability. Chem Eng J 241:35–42CrossRef Xu H, Wang C, Song Y, Zhu J, Xu Y, Yan J, Song Y, Li H (2014) CNT/Ag3PO4 composites with highly enhanced visible light photocatalytic activity and stability. Chem Eng J 241:35–42CrossRef
25.
Zurück zum Zitat Xiang Q, Lang D, Shen T, Liu F (2015) Graphene-modified nanosized Ag3PO4 photocatalysts for enhanced visible-light photocatalytic activity and stability. Appl Catal B Environ 162:196–203CrossRef Xiang Q, Lang D, Shen T, Liu F (2015) Graphene-modified nanosized Ag3PO4 photocatalysts for enhanced visible-light photocatalytic activity and stability. Appl Catal B Environ 162:196–203CrossRef
26.
Zurück zum Zitat Ma J, Chen C, Yu F (2016) Self-regenerative and self-enhanced smart graphene/Ag3PO4 hydrogel adsorbent under visible light. New J Chem 40:3208–3215CrossRef Ma J, Chen C, Yu F (2016) Self-regenerative and self-enhanced smart graphene/Ag3PO4 hydrogel adsorbent under visible light. New J Chem 40:3208–3215CrossRef
27.
Zurück zum Zitat Ma J, Liu Q, Zhu L, Zou J, Wang K, Yang M, Komarneni S (2016) Visible light photocatalytic activity enhancement of Ag3PO4 dispersed on exfoliated bentonite for degradation of rhodamine B. Appl Catal B Environ 182:26–32CrossRef Ma J, Liu Q, Zhu L, Zou J, Wang K, Yang M, Komarneni S (2016) Visible light photocatalytic activity enhancement of Ag3PO4 dispersed on exfoliated bentonite for degradation of rhodamine B. Appl Catal B Environ 182:26–32CrossRef
28.
Zurück zum Zitat Xu JW, Gao ZD, Han K, Liu Y, Song YY (2014) Synthesis of magnetically separable Ag3PO4/TiO2/Fe3O4 heterostructure with enhanced photocatalytic performance under visible light for photoinactivation of bacteria. ACS Appl Mater Interfaces 6:15122–15131CrossRef Xu JW, Gao ZD, Han K, Liu Y, Song YY (2014) Synthesis of magnetically separable Ag3PO4/TiO2/Fe3O4 heterostructure with enhanced photocatalytic performance under visible light for photoinactivation of bacteria. ACS Appl Mater Interfaces 6:15122–15131CrossRef
29.
Zurück zum Zitat Li G, Mao L (2012) Magnetically separable Fe3O4–Ag3PO4 sub-micrometre composite: facile synthesis, high visible light-driven photocatalytic efficiency, and good recyclability. RSC Adv 2:5108–5111CrossRef Li G, Mao L (2012) Magnetically separable Fe3O4–Ag3PO4 sub-micrometre composite: facile synthesis, high visible light-driven photocatalytic efficiency, and good recyclability. RSC Adv 2:5108–5111CrossRef
30.
Zurück zum Zitat Ma J, Zou J, Li L, Yao C, Kong Y, Cui B, Zhu R, Li D (2014) Nanocomposite of attapulgite–Ag3PO4 for Orange II photodegradation. Appl Catal B Environ 144:36–40CrossRef Ma J, Zou J, Li L, Yao C, Kong Y, Cui B, Zhu R, Li D (2014) Nanocomposite of attapulgite–Ag3PO4 for Orange II photodegradation. Appl Catal B Environ 144:36–40CrossRef
31.
Zurück zum Zitat Yu H, Jiao Z, Hu H, Lu G, Ye J, Bi Y (2013) Fabrication of Ag3PO4–PAN composite nanofibers for photocatalytic applications. CrystEngComm 15:4802–4805CrossRef Yu H, Jiao Z, Hu H, Lu G, Ye J, Bi Y (2013) Fabrication of Ag3PO4–PAN composite nanofibers for photocatalytic applications. CrystEngComm 15:4802–4805CrossRef
32.
Zurück zum Zitat Yu H, Dong Q, Jiao Z, Wang T, Ma J, Lu G, Bi Y (2014) Ion exchange synthesis of PAN/Ag3PO4 core–shell nanofibers with enhanced photocatalytic properties. J Mater Chem A 2:1668–1671CrossRef Yu H, Dong Q, Jiao Z, Wang T, Ma J, Lu G, Bi Y (2014) Ion exchange synthesis of PAN/Ag3PO4 core–shell nanofibers with enhanced photocatalytic properties. J Mater Chem A 2:1668–1671CrossRef
33.
Zurück zum Zitat Panthi G, Park S-J, Chae S-H, Kim T-W, Chung H-J, Hong S-T, Park M, Kim H-Y (2017) Immobilization of Ag3PO4 nanoparticles on electrospun PAN nanofibers via surface oximation: bifunctional composite membrane with enhanced photocatalytic and antimicrobial activities. J Ind Eng Chem 45:277–286CrossRef Panthi G, Park S-J, Chae S-H, Kim T-W, Chung H-J, Hong S-T, Park M, Kim H-Y (2017) Immobilization of Ag3PO4 nanoparticles on electrospun PAN nanofibers via surface oximation: bifunctional composite membrane with enhanced photocatalytic and antimicrobial activities. J Ind Eng Chem 45:277–286CrossRef
34.
Zurück zum Zitat Liu J, Zhou P, Zhang L, Ma Z, Liang J, Fong H (2009) Thermo-chemical reactions occurring during the oxidative stabilization of electrospun polyacrylonitrile precursor nanofibers and the resulting structural conversions. Carbon 47:1087–1095CrossRef Liu J, Zhou P, Zhang L, Ma Z, Liang J, Fong H (2009) Thermo-chemical reactions occurring during the oxidative stabilization of electrospun polyacrylonitrile precursor nanofibers and the resulting structural conversions. Carbon 47:1087–1095CrossRef
35.
Zurück zum Zitat Ungár T (2004) Microstructural parameters from X-ray diffraction peak broadening. Scr Mater 51:777–781CrossRef Ungár T (2004) Microstructural parameters from X-ray diffraction peak broadening. Scr Mater 51:777–781CrossRef
36.
Zurück zum Zitat Zhao Z-P, Li J, Chen J, Chen C-X (2005) Nanofiltration membrane prepared from polyacrylonitrile ultrafiltration membrane by low-temperature plasma: 2. Grafting of styrene in vapor phase. J Membr Sci 251:239–245CrossRef Zhao Z-P, Li J, Chen J, Chen C-X (2005) Nanofiltration membrane prepared from polyacrylonitrile ultrafiltration membrane by low-temperature plasma: 2. Grafting of styrene in vapor phase. J Membr Sci 251:239–245CrossRef
37.
Zurück zum Zitat Gonzalez G, Albano C, Herman V, Boyer I, Monsalve A, Brito JA (2012) Nanocomposite building blocks of TiO2–MWCNTf and ZrO2–MWCNTf. Mater Charact 64:96–106CrossRef Gonzalez G, Albano C, Herman V, Boyer I, Monsalve A, Brito JA (2012) Nanocomposite building blocks of TiO2–MWCNTf and ZrO2–MWCNTf. Mater Charact 64:96–106CrossRef
38.
Zurück zum Zitat Zhu M, Chen P, Liu M (2011) Graphene oxide enwrapped Ag/AgX (X = Br, Cl) nanocomposite as a highly efficient visible-light plasmonic photocatalyst. ACS Nano 5:4529–4536CrossRef Zhu M, Chen P, Liu M (2011) Graphene oxide enwrapped Ag/AgX (X = Br, Cl) nanocomposite as a highly efficient visible-light plasmonic photocatalyst. ACS Nano 5:4529–4536CrossRef
39.
Zurück zum Zitat Zhai W, Li G, Yu P, Yang L, Mao L (2013) Silver phosphate/carbon nanotube-stabilized pickering emulsion for highly efficient photocatalysis. J Phys Chem C 117:15183–15191CrossRef Zhai W, Li G, Yu P, Yang L, Mao L (2013) Silver phosphate/carbon nanotube-stabilized pickering emulsion for highly efficient photocatalysis. J Phys Chem C 117:15183–15191CrossRef
40.
Zurück zum Zitat Xu Y, Xu H, Yan J, Li H, Huang L, Zhang Q, Huang C, Wan H (2013) A novel visible-light-response plasmonic photocatalyst CNT/Ag/AgBr and its photocatalytic properties. Phys Chem Chem Phys 15:5821–5830CrossRef Xu Y, Xu H, Yan J, Li H, Huang L, Zhang Q, Huang C, Wan H (2013) A novel visible-light-response plasmonic photocatalyst CNT/Ag/AgBr and its photocatalytic properties. Phys Chem Chem Phys 15:5821–5830CrossRef
Metadaten
Titel
Flexible electrospun MWCNTs/Ag3PO4/PAN ternary composite fiber membranes with enhanced photocatalytic activity and stability under visible-light irradiation
verfasst von
Xiao-Qiong Wu
Jiang-Shan Shen
Fei Zhao
Zai-Dong Shao
Lu-Bin Zhong
Yu-Ming Zheng
Publikationsdatum
23.04.2018
Verlag
Springer US
Erschienen in
Journal of Materials Science / Ausgabe 14/2018
Print ISSN: 0022-2461
Elektronische ISSN: 1573-4803
DOI
https://doi.org/10.1007/s10853-018-2334-0

Weitere Artikel der Ausgabe 14/2018

Journal of Materials Science 14/2018 Zur Ausgabe

    Marktübersichten

    Die im Laufe eines Jahres in der „adhäsion“ veröffentlichten Marktübersichten helfen Anwendern verschiedenster Branchen, sich einen gezielten Überblick über Lieferantenangebote zu verschaffen.