Application of porous ceramic membranes for separation and purification of carbon quantum dots

CHEN Yishan1 CAI Yifeng1 ZHANG Ming1 XUE Fan1 GU Tianyu1 CHEN Xianfu1 QIU Minghui1 FAN Yiqun1

(1.State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu, China 210009)

【Abstract】Carbon quantum dots with uniform size distribution have broad application prospects in the fields of optoelectronic devices, ion detection, nano-sensors, biological imaging and catalysts due to their good optoelectronic properties. An “ultrafiltration-nanofiltration” bi-membrane method was proposed for the separation and purification of carbon quantum dots (CQDs). The molecular weight cutoff (MWCO) of ceramic ultrafiltration (UF) and nanofiltration (NF) membranes was 2000 and 800 and the corresponding Stocks-Einstein sizes were 2.3 nm and 1.4 nm, respectively. The pure water fluxes of UF and NF membranes were 140 and 70 L·(m2·h)−1, respectively. The effects of pH on the fluorescence intensity and particle size distribution of CQDs were studied. At pH = 3, the CQDs were well dispersed and the fluorescence intensity was high. The ceramic UF membrane could effectively reject the large grained impurities. The average size of the CQDs in the permeate was about 2 nm with good dispersion and no agglomeration. The ceramic NF membrane played a great role in the rejection properties to CQDs. Small molecular impurities could be further removed in the concentration and washing process by using NF membrane. After bi-membrane treatment, the emission spectrum changed from multimodal to monomodal distribution, and the peak width narrowed. The luminous purity of CQDs was significantly improved.

【Keywords】 membrane; nanofiltration; ultrafiltration; nanoparticles; carbon quantum dots; purification;


【Funds】 National Natural Science Foundation of China (91534108, 21506093, 21706115) National High Technology Research and Development Program of China (2012AA03A606) Project of Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) “Peak Specialists in Six Industries” High-level Specialist Fund of Jiangsu Province (2012JNHB016)

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(Translated by KANG GD)


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This Article


CN: 11-1946/TQ

Vol 69, No. 10, Pages 4284-4291+4497

October 2018


Article Outline


  • Introduction
  • 1 Experimental
  • 2 Results and discussion
  • 3 Conclusions
  • References