二维材料MXene在水处理领域的应用

doi:10.11868/j.issn.1001-4381.2021.000097

摘要
图/表
参考文献
相关文章
Metrics

全文: PDF(15426 KB)

HTML ( 3 )
输出: BibTeX | EndNote (RIS)

摘要

MXene是一类新兴二维（2D）结构的过渡金属碳/氮化物材料，具有独特的层状结构、亲水性、高导电性和催化活性等特点，在水处理领域受到越来越多的关注。首先介绍了MXene及其合成方法，综述了MXene在吸附、光催化和膜分离等方面的应用。其次讨论了MXene的结构调控、表面改性以及复合等对MXene吸附性能的影响机制和有效异质结的形成、活性晶面的暴露以及贵金属沉积等对MXene基光催化剂催化性能的影响机制；详述了构建高效分离污染物、淡化海水的MXene基分离膜的方法。最后归纳并分析了目前MXene在水处理领域应用中存在的问题，对如何设计性能优异的MXene基水处理材料提出了展望。

	服务

	把本文推荐给朋友
	加入引用管理器
	E-mail Alert
	RSS
	作者相关文章
	张文娟
	寇苗

关键词 ：吸附, 光催化, 膜分离, 水处理

Abstract：

MXene, very recently emerging family of two-dimensional (2D) transition metal carbides and/or nitrides, have attracted a wide range of attention due to unique layered structure, hydrophilicity, high conductivity and catalytic activity.First, synthesis and various applications of MXene in adsorption, photocatalysis and membrane separation were summarized in this review.Then, the effects of structure control, surface modification and composite of MXene on the adsorption performance of MXene and the formation of effective heterojunction, the exposure of active crystal face and the deposition of precious metals on the catalytic performance of MXene based photocatalysts were discussed.The approaches of constructing MXene based separation membrane for separating pollutants and desalinating seawater were described in detail.Finally, the existing problems in the applications of MXene in the field of water treatment were summarized and analyzed, and the prospects of designing MXene based water treatment materials with excellent performance were put forward.

Key words： adsorption photocatalysis membrane separation water treatment

收稿日期: 2021-02-01 出版日期: 2021-09-17

中图分类号:

TQ174

基金资助:国家自然科学基金(51703088);甘肃省高等学校科研项目(2017A-010);兰州理工大学红柳青年基金(061805);2018年高分子材料重点实验室开放基金项目(KF-18-03);博士科研启动基金(061602)

通讯作者: 张文娟 E-mail: wenjuanzhang86@163.com

作者简介: 张文娟(1986-), 女, 副研究员, 博士, 主要从事磁性材料及多孔材料应用研究工作, 联系地址: 甘肃省兰州市七里河区兰工坪路287号兰州理工大学校本部(730050), E-mail: wenjuanzhang86@163.com

引用本文:

张文娟, 寇苗. 二维材料MXene在水处理领域的应用[J]. 材料工程, 2021, 49(9): 14-26.
Wen-juan ZHANG, Miao KOU. Applications of two dimensional material MXene in water treatment. Journal of Materials Engineering, 2021, 49(9): 14-26.

链接本文:

http://jme.biam.ac.cn/CN/10.11868/j.issn.1001-4381.2021.000097 或 http://jme.biam.ac.cn/CN/Y2021/V49/I9/14

Fig.1 Ti₃C₂(OH)₂的三种构型^[18]

Fig.2 Ti₃C₂T_x纳米片去除重金属的性能及机理
(a)ML-Ti₃C₂T_x和DL-Ti₃C₂T_x对Cu的吸附对比^[17]；(b)Ti₃C₂T_x纳米片去除Cr⁶⁺的机理图^[4]

Fig.3 ELF和形成能^[18]
(a)Ti₃C₂(OH)_xF_2-x的ELF；(b)Ti₃C₂(O₂H_2-x-2mF_xPb_m)的ELF；(c)在不同覆盖度下，Ti₃C₂F₂的F原子被—OH官能团取代以及Ti₃C₂(OH)₂的H原子被Li，Na和K离子取代的形成能

Fig.4 MX-SA_4∶20壳体上Hg²⁺吸附的示意图^[23]

Fig.5 (001) TiO₂/Ti₃C₂的光催化活性^[31]
(a)(001)TiO₂/Ti₃C₂上的电荷转移过程；(b)(001)TiO₂/Ti₃C₂界面的能带排列和电荷流示意图；(c)不同水热时间制备的(001)TiO₂/Ti₃C₂T_x和TiO₂/Ti₃C₂T_x的光催化降解速率常数(k)；(d)(001)TiO₂/Ti₃C₂-160 ℃-12 h在紫外光照射下降解MO的循环实验

Fig.6 Ti₃C₂T_x基海水淡化膜^[32]
(a)未经处理的Ti₃C₂T_x膜(MXMs)分别在干燥状态下以及浸泡在去离子水和各种盐溶液(0.2 mol·L^-1)中的层间距；(b)Al³⁺插层的MXMs分别在干燥状态下以及浸泡在去离子水和各种盐溶液(0.2 mol·L^-1)中的层间距；(c)Al³⁺插入两个相邻Ti₃C₂T_x层固定层间距的示意图；(d)未经处理的MXMs和Al³⁺插层的MXMs的离子渗透速率

Fig.7 Ti₃C₂T_x基太阳能脱盐膜^[35]
(a)亲水DL-Ti₃C₂T_x膜在24 h太阳能脱盐之前的光学照片；(b)亲水DL-Ti₃C₂T_x膜在24 h太阳能脱盐之后的光学照片；(c)疏水DL-Ti₃C₂T_x膜在24 h太阳能脱盐之前的光学照片；(d)疏水DL-Ti₃C₂T_x膜在24 h太阳能脱盐之后的光学照片；(e)循环实验中的蒸发速率；(f)太阳能热转换效率；(g)太阳能脱盐前后四种离子盐度的测定；(h)10 mg负载的DL-Ti₃C₂T_x疏水膜在一次太阳光照射下蒸发的实时海水失重

Fig.8 Ti₃C₂T_x基净水膜
(a)多孔膜的制备^[36]；(b)多孔膜表面的SEM照片(插图：宏观照片)^[36]；(c)AAO支撑的多孔膜横截面图的高倍SEM照片(插图：层状结构的呈现)^[36]；(d)室温下M1，Ti₃C₂T_x和Fe(OH)₃的复合膜(M2)和多孔膜分离EB分子的性能比较^[36]；(e)Ti₃C₂T_x膜的SEM横截面照片^[37]；(f)21%Ag@Ti₃C₂T_x膜的SEM横截面照片^[37]

1	SANTHOSH C , VELMURUGAN V , JACOB G , et al. Role of nanomaterials in water treatment applications: a review[J]. Chemical Engineering Journal, 2016, 306, 1116- 1137. doi: 10.1016/j.cej.2016.08.053
2	RASOOL K , PANDEY R P , RASHEED P A , et al. Water treatment and environmental remediation applications of two-dimensional metal carbides (MXenes)[J]. Materials Today, 2019, 30, 80- 102. doi: 10.1016/j.mattod.2019.05.017
3	ZHANG X , ZHAO X D , WU D H , et al. High and anisotropic carrier mobility in experimentally possible Ti₂CO₂ (MXene) monolayers and nanoribbons[J]. Nanoscale, 2015, 7 (38): 16020- 16025. doi: 10.1039/C5NR04717J
4	YING Y L , LIU Y , WANG X Y , et al. Two-dimensional titanium carbide for efficiently reductive removal of highly toxic chromium(Ⅵ) from water[J]. ACS Applied Materials & Interfaces, 2015, 7 (3): 1795- 1803.
5	陈平平. 高通量二维层状膜通道的可控构建[D]. 郑州: 郑州大学, 2018.
5	CHEN P P. The controllable construction of nanochannel in two-dimensional lamellar membrane for high permeance[D]. Zhengzhou: Zhengzhou University, 2018.
6	GUO X , ZHANG X T , ZHAO S J , et al. High adsorption capacity of heavy metals on two-dimensional MXenes: an ab initio study with molecular dynamics simulation[J]. Physical Chemistry Chemical Physics, 2016, 18 (1): 228- 233. doi: 10.1039/C5CP06078H
7	WU L X , LU X B , DHANJAI , et al. 2D transition metal carbide MXene as a robust biosensing platform for enzyme immobilization and ultrasensitive detection of phenol[J]. Biosensors and Bioelectronics, 2018, 107, 69- 75. doi: 10.1016/j.bios.2018.02.021
8	KARAHAN H E , GOH K , ZHANG C F , et al. MXene materials for designing advanced separation membranes[J]. Advanced Materials, 2020, 32 (29): 1906697. doi: 10.1002/adma.201906697
9	郑伟, 杨莉, 陈坚, 等. 二维材料MXene的储能性能与应用[J]. 材料导报, 2018, 32 (8): 2513- 2537.
9	ZHENG W , YANG L , CHEN J , et al. Energy storage and application for 2D nano-material MXenes[J]. Materials Review, 2018, 32 (8): 2513- 2537.
10	ANASORI B , LUHATSKAYA M R , GOGOTSI Y , et al. 2D metal carbides and nitrides(MXenes) for energy storage[J]. Nature Reviews Materials, 2017, 2, 16098. doi: 10.1038/natrevmats.2016.98
11	ALHABEB M , MALESKI K , ANASORI B , et al. Guidelines for synthesis and processing of two-dimensional titanium carbide(Ti₃C₂T_x MXene)[J]. Chemistry of Materials, 2017, 29 (18): 7633- 7644. doi: 10.1021/acs.chemmater.7b02847
12	LI M , LU J , LUO K , et al. Element replacement approach by reaction with lewis acidic molten salts to synthesize nanolaminated MAX phases and MXenes[J]. Journal of the American Chemical Society, 2019, 141, 4730- 4737. doi: 10.1021/jacs.9b00574
13	KAMYSBAYEV V , FILATOV A S , HU H C , et al. Covalent surface modifications and superconductivity of two-dimensional metal carbide MXenes[J]. Science, 2020, 369 (6506): 979- 983. doi: 10.1126/science.aba8311
14	SI C , ZHOU J , SUN Z M . Half-metallic ferromagnetism and surface functionalization-induced metal-insulator transition in graphene-like two-dimensional Cr₂C crystals[J]. ACS Applied Materials & Interfaces, 2015, 7, 17510- 17515.
15	彭超. 二维过渡金属碳化物(MXene)基光催化剂的制备、性能与催化机理的研究[D]. 广州: 华南理工大学, 2017.
15	PENG C. Synthesis, performance and mechanism of 2-Dimensional transition metal carbide(MXene) drived photocatalysts[D]. Guangzhou: South China University of Technology, 2017.
16	LI X G , MA X L , SUN J , et al. Powerful reactive sorption of silver(Ⅰ) and mercury(Ⅱ) onto poly(o-phenylenediamine) microparticles[J]. Langmuir, 2009, 25 (3): 1675- 1684. doi: 10.1021/la802410p
17	SHAHZAD A , RASOOL K , MIRAN W , et al. Two-dimensional Ti₃C₂T_x MXene nanosheets for efficient copper removal from water[J]. ACS Sustainable Chemistry & Engineering, 2017, 5 (12): 11481- 11488.
18	GUO J X , PENG Q M , FU H , et al. Heavy-metal adsorption behavior of two-dimensional alkalization intercalated MXene by first-principles calculations[J]. The Journal of Physical Chemistry C, 2015, 119 (36): 20923- 20930. doi: 10.1021/acs.jpcc.5b05426
19	PENG Q M , GUO J X , ZHANG Q R , et al. Unique lead adsorption behavior of activated hydroxyl group in two-dimensional titanium carbide[J]. Journal of the American Chemical Society, 2014, 136 (11): 4113- 4116. doi: 10.1021/ja500506k
20	ZHENG W , ZHANG P G , TIAN W B , et al. Alkali treated Ti₃C₂T_x MXenes and their dye adsorption performance[J]. Materials Chemistry and Physics, 2018, 206, 270- 276. doi: 10.1016/j.matchemphys.2017.12.034
21	NIGHTINGALE E R J . Phenomenological theory of ion solvation.effective radii of hydrated ions[J]. The Journal of Physical Chemistry, 1959, 63 (9): 1381- 1387. doi: 10.1021/j150579a011
22	SHAHZAD A , RASOOL K , MIRAN W , et al. Mercuric ion capturing by recoverable titanium carbide magnetic nanocomposite[J]. Journal of Hazardous Materials, 2018, 344, 811- 818. doi: 10.1016/j.jhazmat.2017.11.026
23	SHAHZADA A , NAWAZ M , MOZTAHIDA M , et al. Ti₃C₂T_x MXene core-shell spheres for ultrahigh removal of mercuric ions[J]. Chemical Engineering Journal, 2019, 368, 400- 408. doi: 10.1016/j.cej.2019.02.160
24	ZOU G D , GUO J X , PENG Q M , et al. Synthesis of urchin-like rutile titania carbon nanocomposites by iron-facilitated phase transformation of MXene for environmental remediation[J]. Journal of Materials Chemistry A, 2016, 4 (2): 489. doi: 10.1039/C5TA07343J
25	PANDEY R P , RASOOL K , RASHEED P A , et al. Reductive sequestration of toxic bromate from drinking water using lamellar 2D Ti₃C₂T_x(MXene)[J]. ACS Sustainable Chemistry & Engineering, 2018, 6 (6): 7910- 7917.
26	ZHANG Q R , TENG J , ZOU G D , et al. Efficient phosphate sequestration for water purification by unique sandwich-like MXene/magnetic iron oxide nanocomposites[J]. Nanoscale, 2016, 8 (13): 7085- 7093. doi: 10.1039/C5NR09303A
27	LI K K , ZOU G D , JIAO T F , et al. Self-assembled MXene-based nanocomposites via layer-by-layer strategy for elevated adsorption capacities[J]. Colloids and Surfaces A, 2018, 553, 105- 113. doi: 10.1016/j.colsurfa.2018.05.044
28	WANG L , YUAN L Y , CHEN K , et al. Loading actinides in multilayered structures for nuclear waste treatment: the first case study of uranium capture with vanadium carbide MXene[J]. ACS Applied Materials & Interfaces, 2016, 8 (25): 16396- 16403.
29	CHENG L , LI X , ZHANG H W , et al. Two-dimensional transition metal MXene-based photocatalysts for solar fuel generation[J]. Journal of Physical Chemistry Letters, 2019, 10 (12): 3488- 3494. doi: 10.1021/acs.jpclett.9b00736
30	GAO Y P , WANG L B , ZHOU A G , et al. Hydrothermal synthesis of TiO₂/Ti₃C₂ nanocomposites with enhanced photocatalytic activity[J]. Materials Letters, 2015, 150, 62- 64. doi: 10.1016/j.matlet.2015.02.135
31	PENG C , YANG X F , LI Y H , et al. Hybrids of two-dimensional Ti₃C₂ and TiO₂ exposing {001} facets toward enhanced photocatalytic activity[J]. ACS Applied Materials & Interfaces, 2016, 8 (9): 6051- 6060.
32	DING L , LI L B , LIU Y C , et al. Effective ion sieving with Ti₃C₂T_x MXene membranes for production of drinking water from seawater[J]. Nature Sustainability, 2020, 3 (4): 296- 302. doi: 10.1038/s41893-020-0474-0
33	REN C E , ALHABEB M , BYLES B W , et al. Voltage gated ions sieving through 2D MXene Ti₃C₂T_x membranes[J]. ACS Applied Nano Materials, 2018, 1 (7): 3644- 3652. doi: 10.1021/acsanm.8b00762
34	LI R Y , ZHANG L B , SHI L , et al. MXene Ti₃C₂: an effective 2D light-to-heat conversion material[J]. ACS Nano, 2017, 11 (4): 3752- 3759. doi: 10.1021/acsnano.6b08415
35	ZHAO J Q , YANG Y W , YANG C H , et al. A hydrophobic surface enabled salt-blocking 2D Ti₃C₂ MXene membrane for efficient and stable solar desalination[J]. Journal of Materials Chemistry A, 2018, 6 (4): 16196- 16204.
36	DING L , WEI Y Y , WANG Y J , et al. A two-dimensional lamellar membrane: MXene nanosheet stacks[J]. Angewandte Chemie, 2017, 56 (7): 1825- 1829. doi: 10.1002/anie.201609306
37	PANDEY R P , RASOOL K , MADHAVAN V E , et al. Ultrahigh-flux and fouling-resistant membrane based on layered silver/MXene(Ti₃C₂T_x) nanosheets[J]. Journal of Materials Chemistry A, 2018, 6 (8): 3522- 3533. doi: 10.1039/C7TA10888E
38	KANG M K , KIM D W , REN C E , et al. Selective molecular separation on Ti₃C₂T_x-graphene oxide membranes during pressure-driven filtration: comparison with graphene oxide and MXenes[J]. ACS Applied Materials & Interfaces, 2017, 9 (51): 44687- 44694.
39	李猛, 姚宇健, 张轩, 等. 薄层复合膜的纳米改性: 设计、制备及应用[J]. 化工进展, 2018, 38 (1): 365- 381.
39	LI M , YAO Y J , ZHANG X , et al. Nanomaterials for enhancing thin-film composite: design, fabrication, and application[J]. Chemical Industry and Engineering Progress, 2018, 38 (1): 365- 381.
40	吴艺. MXene膜的制备及其液体分离性能研究[D]. 广州: 华南理工大学, 2019.
40	WU Y. Preparation and application in liquid separation of MXene membrane[D]. Guangzhou: South China University of Technology, 2019.
41	RASOOL K , HELAL M A , ALI A , et al. Antibacterial activity of Ti₃C₂T_x MXene[J]. ACS Nano, 2016, 10 (3): 3674- 3684. doi: 10.1021/acsnano.6b00181
42	周璇, 郑云飞, 贾绮林, 等. 新型二维层状纳米材料的抗菌研究进展[J]. 材料工程, 2021, 49 (1): 55- 64.
42	ZHOU X , ZHENG Y F , JIA Q L , et al. Advances in antibacterial research based on two-dimensional nano-materials[J]. Journal of Materials Engineering, 2021, 49 (1): 55- 64.
43	RASOOL K , MAHMOUD K A , JOHNSON D J , et al. Efficient antibacterial membrane based on two-dimensional Ti₃C₂T_x(MXene) nanosheets[J]. Scientific Reports, 2017, 7 (1): 1598. doi: 10.1038/s41598-017-01714-3
44	RASHEED P A , PANDEY R P , RASOOL K , et al. Ultra-sensitive electrocatalytic detection of bromate in drinking water based on Nafion/Ti₃C₂T_x(MXene) modified glassy carbon electrode[J]. Sensors and Actuators B, 2018, 265, 652- 659. doi: 10.1016/j.snb.2018.03.103
45	ZHU X L , LIU B C , HOU H J , et al. Alkaline intercalation of Ti₃C₂ MXene for simultaneous electrochemical detection of Cd(Ⅱ), Pb(Ⅱ), Cu(Ⅱ) and Hg(Ⅱ)[J]. Electrochimica Acta, 2017, 248, 46- 57. doi: 10.1016/j.electacta.2017.07.084
46	LIU H , DUAN C Y , YANG C H , et al. A novel nitrite biosensor based on the direct electrochemistry of hemoglobin immobilized on MXene-Ti₃C₂[J]. Sensors and Actuators B, 2015, 218, 60- 66. doi: 10.1016/j.snb.2015.04.090
47	ZHANG R Y , LIU J , LI Y C . MXene with great adsorption ability toward organic dye: an excellent material for constructing a ratiometric electrochemical sensing platform[J]. ACS Sensors, 2019, 4, 2058- 2064. doi: 10.1021/acssensors.9b00654
48	OREN Y . Capacitive deionization(CDI) for desalination and water treatment—past, present and future(a review)[J]. Desalination, 2008, 228 (1/3): 10- 29.
49	XIE X Q , ZHAO M Q , ANASORI B , et al. Porous heterostructured MXene/carbon nanotube composite paper with high volumetric capacity for sodium-based energy storage devices[J]. Nano Energy, 2016, 26, 513- 523. doi: 10.1016/j.nanoen.2016.06.005
50	LEVI M D , LUKATSKAYA M R , SIGALOV S , et al. Solving the capacitive paradox of 2D MXene using electrochemical quartz-crystal admittance and in situ electronic conductance measurements[J]. Advanced Energy Materials, 2015, 5 (1): 1- 11.
51	SUSS M E , PRESSER V . Water desalination with energy storage electrode materials[J]. Joule, 2018, 2 (1): 10- 15. doi: 10.1016/j.joule.2017.12.010
52	SRIMUK P , KAASIK F , KRÜNER B , et al. MXene as a novel intercalation-type pseudocapacitive cathode and anode for capacitive deionization[J]. Journal of Materials Chemistry A, 2016, 4 (47): 18265- 18271. doi: 10.1039/C6TA07833H
53	BAO W Z , TANG X , GUO X , et al. Porous cryo-dried MXene for efficient capacitive deionization[J]. Joule, 2018, 2 (4): 778- 787. doi: 10.1016/j.joule.2018.02.018
54	SRIMUK P , HALIM J , LEE J , et al. Two-dimensional molybdenum carbide(MXene) with divacancy ordering for brackish and seawater desalination via cation and anion intercalation[J]. ACS Sustainable Chemistry & Engineering, 2018, 6 (3): 3739- 3747.
55	GUO L , WANG X F , LEONG Z Y , et al. Ar plasma modification of 2D MXene Ti₃C₂T_x nanosheets for efficient capacitive desalination[J]. FlatChem, 2018, 8, 17- 24. doi: 10.1016/j.flatc.2018.01.001

[1]	张林琳, 顾学林, 向笑笑, 刘会娥, 陈爽. 石墨烯-羧甲基纤维素复合气凝胶的制备及吸油性能评价[J]. 材料工程, 2022, 50(9): 43-51.
[2]	刘源, 赵华, 李会鹏, 蔡天凤, 王禹程. 碳氯共掺杂介孔g-C₃N₄的气泡模板法制备及光催化性能[J]. 材料工程, 2022, 50(9): 70-77.
[3]	李思骏, 邵兰兴, 冯丽, 程琥, 庄金亮. 二维Ce-MOFs纳米片的合成及可见光介导脱羧氧化性能[J]. 材料工程, 2022, 50(9): 89-96.
[4]	张铭泰, 余少彬, 李希成, 冯萃敏, 石梦童, 汪长征, 王强. 新型复合纳米材料用于光催化降解染料废水的研究进展[J]. 材料工程, 2022, 50(7): 59-68.
[5]	赵卫峰, 郝宁, 张改, 钱慧锦, 马爱洁, 周宏伟, 陈卫星. 苝四羧酸二酰亚胺修饰增强g-C₃N₄光催化性能[J]. 材料工程, 2022, 50(3): 98-106.
[6]	雷铭, 刘岳林, 谢水波, 葛玉杰, 刘迎九. ZnO/g-C₃N₄复合光催化剂的制备及光催化还原U (Ⅵ)[J]. 材料工程, 2022, 50(10): 157-164.
[7]	张建民, 刘宇琦, 李红玑. 活化凹凸棒石合成多级孔钛硅分子筛及其光催化性能研究[J]. 材料工程, 2022, 50(10): 165-171.
[8]	杨泛明, 黎丽君, 肖浪, 廖敏, 张可意, 谭伟石, 贺国文. 聚醚P123和四乙烯五胺双功能化Fe-Zr的CO₂吸附性能[J]. 材料工程, 2021, 49(9): 158-166.
[9]	褚召冉, 陈功, 赵雪伶, 林东海, 陈诚. 光子晶体在光催化领域的研究进展[J]. 材料工程, 2021, 49(8): 43-53.
[10]	李华鹏, 董旭晟, 孙彬, 周国伟. TiO₂/MXene纳米复合材料的可控制备及在光催化和电化学中的应用研究进展[J]. 材料工程, 2021, 49(8): 54-62.
[11]	霍晓文, 于守武, 肖淑娟, 谭小耀. 金属有机框架材料在吸附分离领域的研究进展[J]. 材料工程, 2021, 49(7): 10-20.
[12]	晏秘, 薛云, 申妍铭, 程琥, 庄金亮. 分级结构苯并噻二唑聚合物应用于可见光诱导硫醚选择性氧化[J]. 材料工程, 2021, 49(7): 64-70.
[13]	葛玉杰, 吴姣, 何志强, 王国华, 刘金香. g-C₃N₄基异质耦合光催化剂制备及在环境污染物去除领域的研究进展[J]. 材料工程, 2021, 49(4): 23-33.
[14]	王海博, 李春燕, 李金玲, 王顺平, 寇生中. Fe基非晶合金粉末的研究进展[J]. 材料工程, 2021, 49(4): 34-51.
[15]	向小倩, 廖小刚, 李纲, 胡学步, 田甜. 分级微/纳结构ZnO的制备及其光催化性能[J]. 材料工程, 2021, 49(4): 150-158.

Viewed

Full text

Abstract

Cited

Shared

Discussed