Journal of Radioanalytical and Nuclear Chemistry

, Volume 319, Issue 1, pp 147–158 | Cite as

Characteristics and mechanism of uranium photocatalytic removal enhanced by chelating hole scavenger citric acid in a TiO2 suspension system

  • Mingxue LiuEmail author
  • Lang Luo
  • Faqin DongEmail author
  • Hongfu Wei
  • Xiaoqin Nie
  • Wei Zhang
  • Wenyuan Hu
  • Congcong Ding
  • Pingping Wang


Polycarboxylic acid acts as hole scavenger and chelating agent, which is essential for the photocatalytic removal of multivalent metal ions. The photocatalytic uranium removal, role of chelating hole scavenger citric acid (CA), and removal mechanism were investigated in a TiO2 suspension system. The results show that chelating agent CA is an efficient hole scavenger. The maximum removal efficiency of U(VI) reaches up to 98.6%. The uranium-bearing precipitates contains Na[(UO2)(Cit)], UO2, or UO4·2H2O. The mechanisms for the photocatalytic removal of U(VI) and the role of CA are discussed. These results suggest that proper chelating hole scavengers can promote and regulate the photocatalytic removal of multivalent metal ions.


Photocatalytic removal Uranium Citric acid Chelating hole scavenger Mechanism 



The authors thank the National Basic Research Program of China (973 Program: 2014CB846003), National Key R&D Program of China (2016YFC0502204), National Nature Science Foundation of China (Grant numbers: 41272371, 41502316), and Longshan Academic Talent Research Supporting Program of SWUST (18LZX507).

Supplementary material

10967_2018_6237_MOESM1_ESM.doc (866 kb)
Supplementary material 1 (DOC 865 kb)
10967_2018_6237_MOESM2_ESM.doc (86 kb)
Supplementary material 2 (DOC 86 kb)
10967_2018_6237_MOESM3_ESM.doc (47 kb)
Supplementary material 3 (DOC 47 kb)


  1. 1.
    Lu C, Zhang P, Jiang S, Wu X, Song S, Zhu M, Lou Z, Li Z, Liu F, Liu Y, Wang Y, Le Z (2017) Photocatalytic reduction elimination of UO2 2+ pollutant under visible light with metal-free sulfur doped g-C3N4 photocatalyst. Appl Catal B Environ 200:378–385CrossRefGoogle Scholar
  2. 2.
    He H, Zong M, Dong F, Yang P, Ke G, Liu M, Nie X, Wei Ren, Bian L (2017) Simultaneous removal and recovery of uranium from aqueous solution using TiO2 photoelectrochemical reduction method. J Radioanal Nucl Chem 313:59–67CrossRefGoogle Scholar
  3. 3.
    Lovley DR, Phillips EJP, Gorby YA, Landa ER (1991) Microbial reduction of uranium. Nature 350:413–416CrossRefGoogle Scholar
  4. 4.
    Selli E, Eliet V, Spini MR, Bidoglio G (2000) Effects of humic acids on the photoinduced reduction of U(VI) in the presence of semiconducting TiO2 particles. Environ Sci Technol 34:3742–3748CrossRefGoogle Scholar
  5. 5.
    Salomone VN, Meichtry JM, Schinelli G, Leyva AG, Litter MI (2014) Photochemical reduction of U(VI) in aqueous solution in the presence of 2-propanol. J Photochem Photobiol A: Chem 277:19–26CrossRefGoogle Scholar
  6. 6.
    Kabra K, Chaudhary R, Sawhney RL (2007) Effect of pH on solar photocatalytic reduction and deposition of Cu(II), Ni(II), Pb(II) and Zn(II): speciation modeling and reaction kinetics. J Hazard Mater 149:680–685CrossRefGoogle Scholar
  7. 7.
    Kim G, Igunnu ET, Chen GZ (2014) A sunlight assisted dual purpose photoelectrochemical cell for low voltage removal of heavy metals and organic pollutants in wastewater. Chem Eng J 244:411–421CrossRefGoogle Scholar
  8. 8.
    Chen J, Ollis DF, Rulkens WH, Bruning H (1999) Photocatalyzed deposition and concentration of soluble uranium(VI) from TiO2 suspensions. Coll Surf A 151:339–349CrossRefGoogle Scholar
  9. 9.
    Song S, Huang S, Zhang R, Chen Z, Wen T, Wang S, Hayat T, Alsaedi A, Wang X (2017) Simultaneous removal of U(VI) and humic acid on defective TiO2−x investigated by batch and spectroscopy techniques. Chem Eng J 325:576–587CrossRefGoogle Scholar
  10. 10.
    Amadelli R, Maldotti A, Sostero S, Carassiti V (1991) Photodeposition of uranium oxides onto TiO2 from aqueous uranyl solutions. J Chem Soc, Faraday Trans 87:3267–3273CrossRefGoogle Scholar
  11. 11.
    Eliet V, Bidoglio G (1998) Kinetics of the laser-induced photoreduction of U(VI) in aqueous suspensions of TiO2 particles. Environ Sci Technol 32:3155–3161CrossRefGoogle Scholar
  12. 12.
    Odoh SO, Pan QJ, Shamov GA, Wang F, Fayek M, Schreckenbach G (2012) Theoretical study of the reduction of uranium(VI) aquo complexes on titania particles and by alcohols. Chem Eur J 18:7117–7127CrossRefGoogle Scholar
  13. 13.
    Kim YK, Lee SH, Ryu JH, Park HW (2015) Solar conversion of seawater uranium (VI) using TiO2 electrodes. Appl Catal B Environ 163:584–590CrossRefGoogle Scholar
  14. 14.
    O’Regan B, Grätzel M (1991) A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films. Nature 353:737–739CrossRefGoogle Scholar
  15. 15.
    Selli E, De Giorgi A, Bidoglio G (1996) Humic acid sensitized photoreduction of Cr(VI) on ZnO particles. Environ Sci Technol 30:598–604CrossRefGoogle Scholar
  16. 16.
    Wang YQ, Zhang HM, Wang RH (2008) Investigation of the interaction between colloidal TiO2 and bovine hemoglobin using spectral methods. Colloids Surf B Biointerfaces 65:190–196CrossRefGoogle Scholar
  17. 17.
    Karunakaran C, Jayabharathi J, Jayamoorthy K (2013) Benzimidazole derivative vs. different phases of TiO2-physico-chemical approach. Spectrochim Acta A Mol Biomol Spectrosc 114:303–308CrossRefGoogle Scholar
  18. 18.
    Yamazaki S, Iwai S (2001) Kinetic Studies of reductive deposition of copper(II) ions photoassisted by titanium dioxide. J Phys Chem A 105:11285–11290CrossRefGoogle Scholar
  19. 19.
    Wang G, Zhen J, Zhou L, Wu F, Deng N (2015) Adsorption and photocatalytic reduction of U(VI) in aqueous TiO2 suspensions enhanced with sodium formate. J Radioanal Nucl Chem 304:579–585CrossRefGoogle Scholar
  20. 20.
    Salomone VN, Meichtry JM, Zampieri G, Litter MI (2015) New insights in the heterogeneous photocatalytic removal of U(VI) in aqueous solution in the presence of 2-propanol. Chem Eng J 261:27–35CrossRefGoogle Scholar
  21. 21.
    Salomone VN, Meichtry JM, Litter MI (2015) Heterogeneous photocatalytic removal of U(VI) in the presence of formic acid: U(III) formation. Chem Eng J 270:28–35CrossRefGoogle Scholar
  22. 22.
    Jia H, Chen H, Nulaji G, Li X, Wang C (2015) Effect of low-molecular-weight organic acids on photo-degradation of phenanthrene catalyzed by Fe(III)-smectite under visible light. Chemosphere 138:266–271CrossRefGoogle Scholar
  23. 23.
    Lin L, Liu G, Lv W, Qintie L, Kun Y, Zhang Yu (2013) Removal of chelated copper by TiO2 photocatalysis: synergetic mechanism between Cu(II) and organic ligands. Iran J Chem Chem Eng 32:103–112Google Scholar
  24. 24.
    Martínez A, Vargas R, Galano A (2018) Citric acid: a promising copper scavenger. Comput Theor Chem 1133:47–50CrossRefGoogle Scholar
  25. 25.
    Meichtry JM, Brusa M, Mailhot G, Grela MA, Litter MI (2007) Heterogeneous photocatalysis of Cr(VI) in the presence of citric acid over TiO2 particles: relevance of Cr(V)-citrate complexes. Appl Catal B Environ 71:101–107CrossRefGoogle Scholar
  26. 26.
    Kabra K, Chaudhary R, Sawhney RL (2008) Solar photocatalytic removal of Cu(II), Ni(II), Zn(II) and Pb(II): speciation modeling of metal-citric acid complexes. J Hazard Mater 155:424–432CrossRefGoogle Scholar
  27. 27.
    Marinho BA, Cristóvão RO, Loureiro JM, Boaventura RAR, Vilar VJP (2016) Solar photocatalytic reduction of Cr(VI) over Fe(III) in the presence of organic sacrificial agents. Appl Catal B Environ 192:208–219CrossRefGoogle Scholar
  28. 28.
    Marinho BA, Cristóvão RO, Djellabi R, Loureiro JM, Boaventura RAR, Vilar VJP (2017) Photocatalytic reduction of Cr(VI) over TiO2 -coated cellulose acetate monolithic structures using solar light. Appl Catal B Environ 203:18–30CrossRefGoogle Scholar
  29. 29.
    Meichtry JM, Quici N, Mailhot G, Litter MI (2011) Heterogeneous photocatalytic degradation of citric acid over TiO2: II. Mechanism of citric acid degradation. Appl Catal B Environ 102:555–562CrossRefGoogle Scholar
  30. 30.
    Liu M, Dong F, Yan X, Zeng W, Hou L, Pang X (2010) Biosorption of uranium by Saccharomyces cerevisiae and surface interactions under culture conditions. Bioresour Technol 101:8573–8580CrossRefGoogle Scholar
  31. 31.
    Zhang LP, Xiao CM (2005) Determination citric acid with discoloration spectrophtometry. J Sichuan Univ Sci Eng (Nat Sci Ed) 18:6–8Google Scholar
  32. 32.
    Zong M, He H, Dong F, He P, Sun S, Liu M, Nie X (2016) Electrochemical electron transfer and crystallization process of uranium(IV) in sodium salt solution. Chem J Chin U 37:1701–1709Google Scholar
  33. 33.
    Rajeshwar K, Osugi ME, Chanmanee W, Chenthamarakshan CR, Zanoni MVB, Kajitvichyanukul P, Krishnan-Ayer R (2008) Heterogeneous photocatalytic treatment of organic dyes in air and aqueous media. J Photochem Photobio C Photochem Rev 9:171–192CrossRefGoogle Scholar
  34. 34.
    Benguella B, Benaissa H (2002) Cadmium removal from aqueous solutions by chitin: kinetic and equilibrium studies. Water Res 36:2463–2474CrossRefGoogle Scholar
  35. 35.
    Bai J, Wu X, Fan F, Tian W, Yin X, Zhao L, Fan F, Li Z, Tian L, Qin Z, Guo J (2012) Biosorption of uranium by magnetically modified Rhodotorula glutinis. Enzyme Microb Technol 51:382–387CrossRefGoogle Scholar
  36. 36.
    Yang L, Xiao Y, Liu S, Li Y, Cai Q, Luo S, Zeng G (2010) Photocatalytic reduction of Cr(VI) on WO3 doped long TiO2 nanotube arrays in the presence of citric acid. Appl Catal B Environ 94:142–149CrossRefGoogle Scholar
  37. 37.
    Ohyoshi E, Oda J, Ohyoshi A (1975) Complex formation between the uranyl ion and citric acid. Bull Chem Soc Jpn 48:227–229CrossRefGoogle Scholar
  38. 38.
    Bailey EH, Mosselmans JFW, Schofield PF (2005) Uranyl-citrate speciation in acidic aqueous solutions-an XAS study between 25 and 200 °C. Chem Geol 216:1–16CrossRefGoogle Scholar
  39. 39.
    Mckinley JP (1995) The influence of uranyl hydrolysis and multiple site-binding reactions on adsorption of U(VI) to montmorillonite. Clay Clay Miner 43:586–598CrossRefGoogle Scholar
  40. 40.
    Bonato M, Ragnarsdottir KV, Allen GC (2012) Removal of uranium(VI), lead(II) at the surface of TiO2 nanotubes studied by X-ray photoelectron spectroscopy. Water Air Soil Poll 223:3845–3857CrossRefGoogle Scholar
  41. 41.
    Cahill AE, Burkhart LE (1990) Continuous precipitation of uranium with hydrogen peroxide. Metall Trans B 21:819–826CrossRefGoogle Scholar
  42. 42.
    Allen GC, Trickle IR, Tucker PM (1981) Surface characterization of uranium metal and uranium dioxide using X-ray photoelectron spectroscopy. Philos Mag B 43:689–703CrossRefGoogle Scholar
  43. 43.
    Riba O, Scott TB, Ragnarsdottir KV, Allen GC (2008) Reaction mechanism of uranyl in the presence of zero-valent iron nanoparticles. Geochim Cosmochim Acta 72:4047–4057CrossRefGoogle Scholar
  44. 44.
    Quici N, Morgada ME, Gettar RT, Bolte M, Litter MI (2007) Photocatalytic degradation of citric acid under different conditions: TiO2 heterogeneous photocatalysis against homogeneous photolytic processes promoted by Fe(III) and H2O2. Appl Catal B Environ 71:117–124CrossRefGoogle Scholar
  45. 45.
    Jiang D, Zhao H, Zhang S, John R (2004) Kinetic study of photocatalytic oxidation of adsorbed carboxylic acids at TiO2 porous films by photoelectrolysis. J Catal 223:212–220CrossRefGoogle Scholar
  46. 46.
    Meichtry JM, Quici N, Mailhot G, Litter MI (2011) Heterogeneous photocatalytic degradation of citric acid over TiO2: I. Mechanism of 3-oxoglutaric acid degradation. Appl Catal B Environ 102:454–463CrossRefGoogle Scholar
  47. 47.
    Regazzoni AE, Mandelbaum P, Matsuyoshi M, Schiller S, Bilmes SA, Blesa MA (1998) Adsorption and photooxidation of salicylic acid on titanium dioxide: a surface complexation description. Langmuir 14:868–874CrossRefGoogle Scholar
  48. 48.
    Mao Y, Schoeneich C, Asmus KD (1991) Identification of organic acids and other intermediates in oxidative degradation of chlorinated ethanes on titania surfaces en route to mineralization: a combined photocatalytic and radiation chemical study. J Phys Chem 95:10080–10089CrossRefGoogle Scholar
  49. 49.
    Ding CC, Cheng WC, Sun YB, Wang XK (2015) Effects of Bacillus subtilis on the reduction of U(VI) by nano-Fe0. Geochim Cosmochim Acta 165:86–107CrossRefGoogle Scholar
  50. 50.
    Dan H, Ding Y, Lu X, Chi F, Yuan S (2016) Adsorption of uranium from aqueous solution by mesoporous SBA-15 with various morphologies. J Radioanal Nucl Chem 310:1107–1114CrossRefGoogle Scholar
  51. 51.
    El-Maghrabi HH, Abdelmaged SM, Nada AA, Zahran F, El-Wahab SA, Yahea D, Hussein GM, Atrees MS (2017) Magnetic graphene based nanocomposite for uranium scavenging. J Hazard Mater 322:370–379CrossRefGoogle Scholar

Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2018

Authors and Affiliations

  1. 1.Life Science and Engineering CollegeSouthwest University of Science and TechnologyMianyangPeople’s Republic of China
  2. 2.Key Laboratory of Solid Waste Treatment and Resource RecycleMinistry of Education of ChinaMianyangPeople’s Republic of China
  3. 3.Fundamental Science on Nuclear Wastes and Environmental Safety LaboratorySouthwest University of Science and TechnologyMianyangPeople’s Republic of China

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