光催化去除水体中重金属离子的研究进展

doi:10.12066/j.issn.1007-2861.2245

摘要/Abstract

摘要：

重金属污染的治理是环境问题的重点和难点。光催化技术为重金属的去除提供了一条绿色、可持续的途径。二氧化钛由于独特的光、电化学性能,被视为最适合的光催化剂。然而,由于带隙大、载流子复合速率高等缺陷,限制了其在可见光和自然太阳光下的应用。全面总结了二氧化钛在水体中重金属去除的最新进展,分析了表面修饰、金属和非金属掺杂、固载化、半导体复合等改性技术对重金属去除效率的影响,并对反应机理进行了讨论。最后,对光催化去除重金属的研究现状和存在的问题进行了评述。

关键词: 重金属, 光催化, 二氧化钛

Abstract:

Treatment of heavy metal pollution is challenging, and hence, is the focus of tackling environmental problems. Photocatalysis-based technologies provide a green and sustainable route to heavy metal removal. TiO$_{2}$ is regarded as the most suitable photocatalyst because of its unique photo- and electrochemical performances. However, its application under visible light and natural sunlight is limited due to its large band gap and high carrier recombination rate. This review summarises a series of photo catalysts that have been developed in the recent years for heavy metal removal. Strategies for improving the photocatalytic activity of TiO$_{2}$, which involve surface modification, metal/non-metal doping, immobilisation, and coupling with other semiconductors, were summarised; the corresponding reaction mechanisms were also discussed. Moreover, the status and drawbacks of the current research on the photocatalytic removal of heavy metals were critically discussed.

Key words: heavy metal, photocatalysis, TiO$_{2}$

中图分类号:

许振民, 施利毅. 光催化去除水体中重金属离子的研究进展[J]. 上海大学学报(自然科学版), 2020, 26(4): 491-505.

XU Zhenmin, SHI Liyi. Review on photocatalytic removal of heavy metals from water[J]. Journal of Shanghai University（Natural Science Edition）, 2020, 26(4): 491-505.

图/表 8

图 1

图 2

图 3

图 4

图 5

图 6

图 7

图 8

参考文献 88

[1]	Ali M, Assirey E A, Abdel S M, et al. Low temperature-calcined TiO$_{2}$ for visible light assisted decontamination of 4-nitrophenol and hexavalent chromium from wastewater[J]. Scientific Reports, 2019,9(1):19354-19363. doi: 10.1038/s41598-019-55912-2 pmid: 31852968
[2]	Bi J, Huang X, Wang J, et al. Oil-phase cyclic magnetic adsorption to synthesize Fe$_{3}$O$_{4}$@C@TiO$_{2}$-nanotube composites for simultaneous removal of Pb(II) and Rhodamine B[J]. Chemical Engineering Journal, 2019,366(15):50-61. doi: 10.1016/j.cej.2019.02.017
[3]	Li S, Cai J, Wu X, et al. TiO$_{2}$@Pt@CeO$_{2}$ nanocomposite as a bifunctional catalyst for enhancing photo-reduction of Cr (VI) and photo-oxidation of benzyl alcohol[J]. Journal of Hazardous Materials, 2018,346(15):52-61. doi: 10.1016/j.jhazmat.2017.12.001
[4]	Wang H, Gao Q, Li H, et al. Hydrous titania nanosheets constructed hierarchical hollow microspheres as a highly efficient dual-use decontaminant for elimination of heavy metal ions and organic pollutants[J]. Chemical Engineering Journal, 2020,381(1):122638-122642. doi: 10.1016/j.cej.2019.122638
[5]	Chen D M, Sun C X, Liu C S, et al. Stable layered semiconductive Cu(I)-Organic framework for efficient visible-light-driven Cr(VI) reduction and H$_{2}$ evolution[J]. Inorganic Chem, 2018,57(13):7975-7981. doi: 10.1021/acs.inorgchem.8b01137
[6]	Chen S, Za J, Yang B, et al. Descriptor design in the computational screening of Ni-based catalysts with balanced activity and stability for dry reforming of methane reaction[J]. ACS Catalysis, 2020,10(5):3074-3083. doi: 10.1021/acscatal.9b04429
[7]	Chen W B, Yang Z F, Xie Z, et al. Benzothiadiazole functionalized D—A type covalent organic frameworks for effective photocatalytic reduction of aqueous chromium(VI)[J]. Journal of Materials Chemistry A, 2019,7(3):998-1004. doi: 10.1039/C8TA10046B
[8]	Du X D, Yi X H, Wang P, et al. Robust photocatalytic reduction of Cr(VI) on UiO-66-NH$_{2}$(Zr/Hf) metal-organic framework membrane under sunlight irradiation[J]. Chemical Engineering Journal, 2019,356(15):393-399. doi: 10.1016/j.cej.2018.09.084
[9]	Duresa L W, Kuo D H, Ahmed K E, et al. Highly enhanced photocatalytic Cr(VI) reduction using In-doped Zn(O,S) nanoparticles[J]. New Journal of Chemistry, 2019,43(22):8746-8754. doi: 10.1039/C9NJ01511F
[10]	Lei Z D, Xue Y C, Chen W Q, et al. The influence of carbon nitride nanosheets doping on the crystalline formation of MIL-88B(Fe) and the photocatalytic activities[J]. Small, 2018,14(35):1802045-1802053. doi: 10.1002/smll.201802045
[11]	Li H, Deng F, Zheng Y, et al. Visible-light-driven Z-scheme rGO/Bi$_{2}$S$_{3}$—BiOBr heterojunctions with tunable exposed BiOBr (102) facets for efficient synchronous photocatalytic degradation of 2-nitrophenol and Cr(VI) reduction[J]. Environmental Science: Nano, 2019,6(12):3670-3683. doi: 10.1039/C9EN00957D
[12]	Liu J M, Ye Y, Sun X D, et al. A multifunctional Zr(IV)-based metal-organic framework for highly efficient elimination of Cr(VI) from the aqueous phase[J]. Journal of Materials Chemistry A, 2019,7(28):16833-16841. doi: 10.1039/C9TA04026A
[13]	Mei Q, Zhang F, Wang N, et al. TiO$_{2}$/Fe$_{2}$O$_{3}$ heterostructures with enhanced photocatalytic reduction of Cr(VI) under visible light irradiation[J]. RSC Advances, 2019,9(39):22764-22771. doi: 10.1039/C9RA03531A
[14]	Qiao X Q, Zhang Z W, Li Q H, et al. In situ synjournal of n-n Bi$_{2}$MoO$_{6}$ & Bi$_{2}$S$_{3}$ heterojunctions for highly efficient photocatalytic removal of Cr(VI)[J]. Journal of Materials Chemistry A, 2018,6(45):22580-22589. doi: 10.1039/C8TA08294D
[15]	Ren Z, Liu X, Zhuge Z, et al. MoSe$_{2}$/ZnO/ZnSe hybrids for efficient Cr(VI) reduction under visible light irradiation[J]. Chinese Journal of Catalysis, 2020,41(1):180-187. doi: 10.1016/S1872-2067(19)63484-4
[16]	Sultana S, Mansingh S, Parida K M. Rational design of light induced self-healed Fe based oxygen vacancy rich CeO$_{2}$ (CeO$_{2}$NS-FeOOH/Fe$_{2}$O$_{3})$ nanostructure materials for photocatalytic water oxidation and Cr(VI) reduction[J]. Journal of Materials Chemistry A, 2018,6(24):11377-11389. doi: 10.1039/C8TA02539H
[17]	Wang X S, Chen C H, Ichihara F, et al. Integration of adsorption and photosensitivity capabilities into a cationic multivariate metal-organic framework for enhanced visible-light photoreduction reaction[J]. Applied Catalysis B: Environmental, 2019,253(15):323-330. doi: 10.1016/j.apcatb.2019.04.074
[18]	Wei W, Zhang Z, You G, et al. Preparation of recyclable MoO$_{3}$ nanosheets for visible-light driven photocatalytic reduction of Cr(VI)[J]. RSC Advances, 2019,9(49):28768-28774. doi: 10.1039/C9RA05644K
[19]	Wu H H, Chang C W, Lu D, et al. Synergistic effect of hydrochloric acid and phytic acid doping on polyaniline-coupled g-C$_{3}$N$_{4}$ nanosheets for photocatalytic Cr(VI) reduction and dye degradation[J]. ACS Appl Mater Interfaces, 2019,11(39):35702-35712. doi: 10.1021/acsami.9b10555 pmid: 31532604
[20]	Yang H, Jiang L, Wang W, et al. One-pot synjournal of CdS/metal-organic framework aerogel composites for efficient visible photocatalytic reduction of aqueous Cr(VI)[J]. RSC Advances, 2019,9(64):37594-37597. doi: 10.1039/C9RA08339A
[21]	Yu Y, Yang X, Zhao Y, et al. Engineering the band gap states of the rutile TiO$_{2}$ (110) surface by modulating the active heteroatom[J]. Angew Chem: Int Ed, 2018,57(28):8550-8554. doi: 10.1002/anie.v57.28
[22]	Zhang H, Li P, Wang Z, et al. Sustainable disposal of Cr(VI): adsorption-reduction strategy for treating textile wastewaters with amino-functionalized boehmite hazardous solid wastes[J]. ACS Sustainable Chemistry & Engineering, 2018,6(5):6811-6819.
[23]	Zhu C, Liu F, Song L, et al. Magnetic Fe$_{3}$O$_{4}$@polyaniline nanocomposites with a tunable core-shell structure for ultrafast microwave-energy-driven reduction of Cr(VI)[J]. Environmental Science: Nano, 2018,5(2):487-496. doi: 10.1039/C7EN01075C
[24]	Raja A, Rajase P, Selva K, et al. Efficient photoreduction of hexavalent chromium using the reduced graphene Oxide-Sm$_{2}$MoO$_{6}$-TiO$_{2}$ catalyst under visible light illumination[J]. ACS Omega, 2020,5(12):6414-6422. doi: 10.1021/acsomega.9b03923 pmid: 32258876
[25]	Vellaichamy B, Periakaruppan P, Nagulan B. Reduction of Cr(VI) from wastewater using a novel in situ-synthesized PANI/MnO$_{2}$/TiO$_{2}$ nanocomposite: renewable, selective, stable, and synergistic catalysis[J]. ACS Sustainable Chemistry & Engineering, 2017,5(10):9313-9324.
[26]	Wang D, Xu Y, Jing L, et al. In situ construction efficient visible-light-driven three-dimensional Polypyrrole/Zn$_{3}$In$_{2}$S$_{6}$ nanoflower to systematically explore the photoreduction of Cr(VI): performance, factors and mechanism[J]. Journal of Hazard Mater, 2020,384(15):121480-121489. doi: 10.1016/j.jhazmat.2019.121480
[27]	Ghafoor S, Hussain S Z, Waseem S, et al. Photo-reduction of heavy metal ions and photo-disinfection of pathogenic bacteria under simulated solar light using photosensitized TiO$_{2}$ nanofibers[J]. RSC Advances, 2018,8(36):20354-20362. doi: 10.1039/C8RA01237G
[28]	Kanakaraju D, Rusydah N, Lim Y C, et al. Concurrent removal of Cr$^{3+}$, Cu(II), and Pb(II) ions from water by multifunctional TiO$_{2}$/Alg/FeNPs beads[J]. Sustainable Chemistry and Pharmacy, 2019,14:100176-100188. doi: 10.1016/j.scp.2019.100176
[29]	Luo Z, Qu L, Jia J, et al. TiO$_{2}$ /EDTA-rich carbon composites: synjournal, characterization and visible-light-driven photocatalytic reduction of Cr(VI)[J]. Chinese Chemical Letters, 2018,29(3):547-550. doi: 10.1016/j.cclet.2017.09.025
[30]	Duan L, Liu H, Muhammad Y, et al. Photo-mediated co-loading of highly dispersed MnO$_x$-Pt on g-C$_{3}$N$_{4}$ boosts the ambient catalytic oxidation of formaldehyde[J]. Nanoscale, 2019,11:8160-8169. doi: 10.1039/c8nr08731h pmid: 30723852
[31]	Zhang H, Shi L, Zhao Y, et al. A simple method to enhance the lifetime of Ni-rich cathode by using low-temperature dehydratable molecular sieve as water scavenger[J]. Journal of Power Sources, 2019,435:226773-226779. doi: 10.1016/j.jpowsour.2019.226773
[32]	Li Y, Bian Y, Qin H, et al. Photocatalytic reduction behavior of hexavalent chromium on hydroxyl modified titanium dioxide[J]. Applied Catalysis B: Environmental, 2017,206(5):293-299. doi: 10.1016/j.apcatb.2017.01.044
[33]	Deng X, Chen Y, Wen J, et al. Polyaniline-TiO$_{2}$ composite photocatalysts for light-driven hexavalent chromium ions reduction[J]. Science Bulletin, 2020,65(2):105-112. doi: 10.1016/j.scib.2019.10.020
[34]	Hosseini F, Mohebbi S. High efficient photocatalytic reduction of aqueous Zn$^{2+}$, Pb$^{2+}$ and Cu$^{2+}$ ions using modified titanium dioxide nanoparticles with amino acids[J]. Journal of Industrial and Engineering Chemistry, 2020,85:190-195. doi: 10.1016/j.jiec.2020.01.040
[35]	Zhen M X, Ru Z, Yao C, et al. Ordered mesoporous Fe/TiO$_{2}$ with light enhanced photo-Fenton activity[J]. Chinese Journal of Catalysis, 2019,40:631-637.
[36]	Kara F, Kurban M, Coskun B, et al. Evaluation of electronic transport and optical response of two-dimensional Fe-doped TiO$_{2}$ thin films for photodetector applications[J]. Optik, 2020,210:164605-164612. doi: 10.1016/j.ijleo.2020.164605
[37]	Ghafoor S, Inayat A, Aftab F, et al. TiO$_{2}$ nanofibers embedded with g-C$_{3}$N$_{4}$ nanosheets and decorated with Ag nanoparticles as Z-scheme photocatalysts for environmental remediation[J]. Journal of Environmental Chemical Engineering, 2019,7(6):103452-103462. doi: 10.1016/j.jece.2019.103452
[38]	Liang C, Niu C G, Zhang L, et al. Construction of 2-D heterojunction system with enhanced photocatalytic performance: plasmonic Bi and reduced graphene oxide co-modified Bi$_{5}$O$_{7}$I with high-speed charge transfer channels[J]. Journal of Hazard Mater, 2019,361:245-258. doi: 10.1016/j.jhazmat.2018.08.099
[39]	Liu S X. Removal of copper (VI) from aqueous solution by Ag/TiO$_{2}$ photocatalysis[J]. Bulletin of Environmental Contamination and Toxicology, 2005,74(4):706-14. pmid: 16094885
[40]	Ravishankar T N, Vaz M O, Ramakrishnappa T, et al. Ionic liquid assisted hydrothermal syntheses of Au doped TiO$_{2}$ NPs for efficient visible-light photocatalytic hydrogen production from water, electrochemical detection and photochemical detoxification of hexavalent chromium (Cr(VI))[J]. RSC Advances, 2017,7(68):43233-43244. doi: 10.1039/C7RA04944G
[41]	Misra M, Chowdhury S R, Singh N, et al. TiO$_{2}$@Au@CoMn$_{2}$O$_{4}$ core-shell nanorods for photo-electrochemical and photocatalytic activity for decomposition of toxic organic compounds and photo reduction of Cr(VI) ion[J]. Journal of Alloys and Compounds, 2020,824:153861-153871. doi: 10.1016/j.jallcom.2020.153861
[42]	Wang S, Xie Y, Cheng W, et al. Efficient photocatalytic removal of aqueous Cr(VI) by N-F-Al tri-doped TiO$_{2}$[J]. Korean Journal of Chemical Engineering, 2017,34(9):2507-2513. doi: 10.1007/s11814-017-0161-7
[43]	Tanaka A, Nakanishi K, Hamada R, et al. Simultaneous and stoichiometric water oxidation and Cr(VI) reduction in aqueous suspensions of functionalized plasmonic photocatalyst Au/TiO$_{2}$-Pt under irradiation of green light[J]. ACS Catalysis, 2013,3(8):1886-1891. doi: 10.1021/cs400433r
[44]	Udaya B, Lakshmana N, Shankar M V, et al. One-pot synjournal of Cu-TiO$_{2}$/CuO nanocomposite: application to photocatalysis for enhanced H$_{2}$ production, dye degradation & detoxification of Cr (VI)[J]. International Journal of Hydrogen Energy, 2020,45(13):7813-7828. doi: 10.1016/j.ijhydene.2019.10.081
[45]	Zhou L, Wang L, Lei J, et al. Fabrication of TiO$_{2}$/Co-g-C$_{3}$N$_{4}$ heterojunction catalyst and its photocatalytic performance[J]. Catalysis Communications, 2017,89(10):125-128. doi: 10.1016/j.catcom.2016.09.022
[46]	Jiang W, Hu X, Yaseen M, et al. Template/surfactant free and UV light irradiation assisted fabrication of Mn-Co oxides composite nanorings: structure and synjournal mechanism[J]. Progress in Natural Science: Materials International, 2019,29:163-169. doi: 10.1016/j.pnsc.2019.02.002
[47]	Luo D, Yan R, Fu C, et al. Cu(0)/TiO$_{2}$ composite byproduct from photo-reduction of acidic Cu-containing wastewater and its reuse as a catalyst[J]. Journal of Water Process Engineering, 2019,32:100958-100969 doi: 10.1016/j.jwpe.2019.100958
[48]	Ali I, Kim J O. Visible-light-assisted photocatalytic activity of bismuth-TiO$_{2}$ nanotube composites for chromium reduction and dye degradation[J]. Chemosphere, 2018,207:285-292. pmid: 29803877
[49]	Murakami N, Chiyoya T, Tsubota T, et al. Switching redox site of photocatalytic reaction on titanium(IV) oxide particles modified with transition-metal ion controlled by irradiation wavelength[J]. Applied Catalysis A: General, 2008,348(1):148-152. doi: 10.1016/j.apcata.2008.06.040
[41]	Yan R, Luo D, Fu C, et al. Simultaneous removal of Cu(II) and Cr(VI) ions from wastewater by photoreduction with TiO$_{2}$-ZrO$_{2}$[J]. Journal of Water Process Engineering, 2020,33:101052-101063.
[51]	Zabihi S A, Koush S, Pishna M, et al. Synjournal of cellulose acetate/chitosan/SWCNT/ Fe$_{3}$O$_{4}$/TiO$_{2}$ composite nanofibers for the removal of Cr(VI), As(V), Methylene blue and Congo red from aqueous solutions[J]. International Journal of Biol Macromol, 2019,140:1296-1304. doi: 10.1016/j.ijbiomac.2019.08.214
[52]	Qiu J, Li M, Xu J, et al. Bismuth sulfide bridged hierarchical Bi$_{2}$S$_{3}$/BiOCl@ZnIn$_{2}$S$_{4}$ for efficient photocatalytic Cr(VI) reduction[J]. Journal of Hazard Mater, 2020,389(5):121858-121863. doi: 10.1016/j.jhazmat.2019.121858
[53]	Chen X, Sun H, Zhang J, et al. Synjournal of visible light responsive iodine-doped mesoporous TiO$_{2}$ by using biological renewable lignin as template for degradation of toxic organic pollutants[J]. Applied Catalysis B: Environmental, 2019,252(5):152-163. doi: 10.1016/j.apcatb.2019.04.034
[54]	Hamdy M S. One-step synjournal of M-doped TiO$_{2}$ nanoparticles in TUD-1 (M-TiO$_{2}$-TUD-1, M=Cr or V) and their photocatalytic performance under visible light irradiation[J]. Journal of Molecular Catalysis A: Chemical, 2014,393(1):39-46. doi: 10.1016/j.molcata.2014.05.039
[55]	Liu B, Liu X, Li L, et al. ZnIn$_{2}$S$_{4}$ flowerlike microspheres embedded with carbon quantum dots for efficient photocatalytic reduction of Cr(VI)[J]. Chinese Journal of Catalysis, 2018,39(12):1901-1909. doi: 10.1016/S1872-2067(18)63137-7
[56]	Wang Y, Rao L, Wang P, et al. Photocatalytic activity of N-TiO$_{2}$/O-doped N vacancy g-C$_{3}$N$_{4}$ and the intermediates toxicity evaluation under tetracycline hydrochloride and Cr(VI) coexistence environment[J]. Applied Catalysis B: Environmental, 2020,262:118308-118338. doi: 10.1016/j.apcatb.2019.118308
[57]	Xu M, Chen Y, Qin J, et al. Unveiling the role of defects on oxygen activation and photodegradation of organic pollutants[J]. Environment Science & Technology, 2018,52(23):13879-13886. doi: 10.1021/acs.est.8b03558
[58]	Bai X, Jia J, Du Y, et al. Multi-level trapped electrons system in enhancing photocatalytic activity of TiO$_{2 }$ nanosheets for simultaneous reduction of Cr(VI) and RhB degradation[J]. Applied Surface Science, 2020,503(15):144298-144307. doi: 10.1016/j.apsusc.2019.144298
[59]	Yang Y, Wang G, Deng Q, et al. Enhanced photocatalytic activity of hierarchical structure TiO$_{2}$ hollow spheres with reactive (001) facets for the removal of toxic heavy metal Cr(VI)[J]. RSC Advances, 2014,4(65):34577-34583. doi: 10.1039/c4ra04787g
[60]	Han L, Zhong Y, Lei K, et al. Carbon dot-SnS$_{2}$ heterojunction photocatalyst for photoreduction of Cr(VI) under visible light: a combined experimental and first-principles DFT study[J]. The Journal of Physical Chemistry C, 2019,123(4):2398-2409. doi: 10.1021/acs.jpcc.8b10059
[61]	Zhang Y, Zhao Y, Xu Z, et al. Carbon quantum dots implanted CdS nanosheets: efficient visible-light-driven photocatalytic reduction of Cr(VI) under saline conditions[J]. Applied Catalysis B: Environmental, 2020,262:118306-118317. doi: 10.1016/j.apcatb.2019.118306
[62]	Shi C, Qi H, Sun Z, et al. Carbon dot-sensitized urchin-like Ti$^{3+}$ self-doped TiO$_{2}$ photocatalysts with enhanced photoredox ability for highly efficient removal of Cr(VI) and RhB[J]. Journal of Materials Chemistry C, 2020,8(7):2238-2247. doi: 10.1039/C9TC05513D
[63]	Zhang Y, Xu M, Li H, et al. The enhanced photoreduction of Cr(VI) to Cr$^{3+}$ using carbon dots coupled TiO$_{2}$ mesocrystals[J]. Applied Catalysis B: Environmental, 2018,226(15):213-219. doi: 10.1016/j.apcatb.2017.12.053
[64]	Wu Y, Chen G, Wang Z, et al. In situ constructed Ag/C conductive network enhancing the C-rate performance of Si based anode[J]. Journal of Energy Storage, 2018,17:102-108. doi: 10.1016/j.est.2018.02.016
[65]	Zheng H, Wang Z, Shi L, et al. Enhanced thermal stability and lithium ion conductivity of polyethylene separator by coating colloidal SiO$_{2}$ nanoparticles with porous shell[J]. Journal of Colloid and Interface Science, 2019,554:29-38. doi: 10.1016/j.jcis.2019.06.102 pmid: 31276959
[66]	Gomaa H, Shenashen M A, Yamaguchi H, et al. Highly-efficient removal of AsV, Pb$^{2+}$, Fe$^{3+}$, and Al$^{3+}$ pollutants from water using hierarchical, microscopic TiO$_{2}$ and TiOF$_{2}$ adsorbents through batch and fixed-bed columnar techniques[J]. Journal of Cleaner Production, 2018,182:910-925. doi: 10.1016/j.jclepro.2018.02.063
[67]	Kanakaraju D, Rusydah N, Chin L Y, et al. Concurrent removal of Cr(III), Cu(II), and Pb(II) ions from water by multifunctional TiO$_{2}$/Alg/FeNPs beads[J]. Sustainable Chemistry and Pharmacy, 2019,14:100176-100185. doi: 10.1016/j.scp.2019.100176
[68]	Yong W, Chang P, Erika P O, et al. Cr(VI) adsorption on activated carbon: mechanisms, modeling and limitations in water treatment[J]. Journal of Environmental Chemical Engineering, 2020,8:104031-104038. doi: 10.1016/j.jece.2020.104031
[69]	Abbas K K, Ghaban A A. Enhanced solar light photoreduction of innovative TiO$_{2}$ nanospherical shell by reduced graphene oxide for removal silver ions from aqueous media[J]. Journal of Environmental Chemical Engineering, 2019,7(3):103168-103181. doi: 10.1016/j.jece.2019.103168
[70]	Khamb D, Srirattanl S, Tang I M, et al. TiO$_{2}$-rGO nanocomposite as a photo catalyst for the reduction of Cr(VI)[J]. Materials Research Bulletin, 2018,107:236-241. doi: 10.1016/j.materresbull.2018.07.002
[71]	Wang G, Fan W, Li Q, et al. Enhanced photocatalytic New Coccine degradation and Pb(II) reduction over graphene oxide-TiO$_{2}$ composite in the presence of aspartic acid-beta- cyclodextrin[J]. Chemosphere, 2019,216:707-714. doi: 10.1016/j.chemosphere.2018.10.199 pmid: 30391892
[72]	Yan X, Ye K, Zhang T, et al. Formation of three-dimensionally ordered macroporous TiO$_2$@nanosheet SnS$_2$ heterojunctions for exceptional visible-light driven photocatalytic activity[J]. New Journal of Chemistry, 2017,41(16):8482-8489. doi: 10.1039/C7NJ01421J
[73]	Zhang H, Wang X, Li N, et al. Synjournal and characterization of TiO$_{2}$/graphene oxide nanocomposites for photoreduction of heavy metal ions in reverse osmosis concentrate[J]. RSC Advances, 2018,8(60):34241-34251. doi: 10.1039/C8RA06681G
[74]	Vajedi F, Dehg H. The characterization of TiO$_{2}$-reduced graphene oxide nanocomposites and their performance in electrochemical determination for removing heavy metals ions of cadmium(II), lead(II) and copper(II)[J]. Materials Science and Engineering: B, 2019,243:189-198. doi: 10.1016/j.mseb.2019.04.009
[75]	Liu H, Liu X Y, Yang W W, et al. Photocatalytic dehydrogenation of formic acid promoted by a superior PdAg@g-C$_{3}$N$_{4}$ Mott-Schottky heterojunction[J]. Journal of Materials Chemistry C, 2019,7:2022-2026. doi: 10.1039/C8TC06010J
[76]	Wang Y J, Bao S Y, Liu Y Q, et al. Efficient photocatalytic reduction of Cr(VI) in aqueous solution over CoS$_{2}$/g-C$_{3}$N$_{4}$-rGO nanocomposites under visible light[J]. Applied Surface Science, 2020,510:145495-145505. doi: 10.1016/j.apsusc.2020.145495
[77]	Bao S Y, Liu H, Liu Y Q, et al. Amino-functionalized graphene oxide-supported networked Pd-Ag nanowires as highly effificient catalyst for reducing Cr(VI) in industrial efflfluent by formic acid[J]. Chemosphere, 2020,257:127245-127253. doi: 10.1016/j.chemosphere.2020.127245 pmid: 32505944
[78]	Bao S Y, Yang W W, Wang Y J, et al. PEI grafted amino-functionalized graphene oxide nanosheets for ultrafast and high selectivity removal of Cr(VI) from aqueous solutions by adsorption combined with reduction: behaviors and mechanisms[J]. Chemical Engineering Journal, 2020,399:125762-125773. doi: 10.1016/j.cej.2020.125762
[79]	Bao S Y, Yang W W, Wang Y J, et al. One-pot synjournal of magnetic graphene oxide composites as an efficient and recoverable adsorbent for Cd(II) and Pb(II) removal from aqueous solution[J]. Journal of Hazardous Materials, 2020,381:120914-120926. doi: 10.1016/j.jhazmat.2019.120914 pmid: 31351227
[80]	Wang X, Sun M, Murugananthan M, et al. Electrochemically self-doped WO$_{3}$/TiO$_{2}$ nanotubes for photocatalytic degradation of volatile organic compounds[J]. Applied Catalysis B: Environmental, 2020,260:118205-118216. doi: 10.1016/j.apcatb.2019.118205
[81]	Abidi M, Assadi A, Bouzaza A, et al. Photocatalytic indoor/outdoor air treatment and bacterial inactivation on Cu$_{x}$O/TiO$_{2}$ prepared by HiPIMS on polyester cloth under low intensity visible light[J]. Applied Catalysis B: Environmental, 2019,259:118074-118055 doi: 10.1016/j.apcatb.2019.118074
[82]	Zhang W, Li G, Liu H, et al. Micro/nano-bubble assisted synjournal of Au/TiO$_{2}$@CNTs composite photocatalyst for photocatalytic degradation of gaseous styrene and its enhanced catalytic mechanism[J]. Environmental Science: Nano, 2019,6:948-958. doi: 10.1039/C8EN01375F
[83]	Wang Z, Xie X, Wang X, et al. Difference of photodegradation characteristics between single and mixed VOC pollutants under simulated sunlight irradiation[J]. Journal of Photochemistry & Photobiology A: Chemistry, 2019,384:112029-112039.
[84]	You S Z, Hu Y, Liu X C, et al. Synergetic removal of Pb(II) and dibutyl phthalate mixed pollutants on Bi$_{2}$O$_{3}$-TiO$_{2 }$composite photocatalyst under visible light[J]. Applied Catalysis B: Environmental, 2018,232(15):288-298. doi: 10.1016/j.apcatb.2018.03.025
[85]	Yuan R, Yue C, Qiu J, et al. Highly efficient sunlight-driven reduction of Cr(VI) by TiO$_{2}$@NH$_{2}$-MIL-88B(Fe) heterostructures under neutral conditions[J]. Applied Catalysis B: Environmental, 2019,251(15):229-239. doi: 10.1016/j.apcatb.2019.03.068
[86]	Du J, Ma S, Liu H, et al. Uncovering the mechanism of novel AgInS$_{2}$ nanosheets/TiO$_{2}$ nanobelts composites for photocatalytic remediation of combined pollution[J]. Applied Catalysis B: Environmental, 2019,259(15):118062-118077. doi: 10.1016/j.apcatb.2019.118062
[87]	Bi J J, Huang X, Wang J K, et al. Oil-phase cyclic magnetic adsorption to synthesize Fe$_{3}$O$_{4}$@C@TiO$_{2}$-nanotube composites for simultaneous removal of Pb(II) and Rhodamine B[J]. Chemical Engineering Journal, 2019,366:50-61. doi: 10.1016/j.cej.2019.02.017
[88]	Zabihisahebi A, Koushkbaghis S, Pishnamazi M, et al. Synjournal of cellulose acetate/chitosan/SWCNT/Fe$_{3}$O$_{4}$/TiO$_{2}$ composite nanofifibers for the removal of Cr(VI), As(V), Methylene blue and Congo red from aqueous solutions[J]. International Journal of Biological Macromolecules, 2019,140:1296-1304. doi: 10.1016/j.ijbiomac.2019.08.214 pmid: 31465804