Selective and fast recovery of rare earth elements from industrial wastewater by porous β-cyclodextrin and magnetic β-cyclodextrin polymers

François Nkinahamira; Alaaeddin Alsbaiee; Qiaoting Zeng; Yan Li; Yiqing Zhang; Meiling Feng; Chang-Ping Yu; Qian Sun

doi:10.1016/j.watres.2020.115857

Selective and fast recovery of rare earth elements from industrial wastewater by porous β-cyclodextrin and magnetic β-cyclodextrin polymers

Water Res. 2020 Aug 15:181:115857. doi: 10.1016/j.watres.2020.115857. Epub 2020 May 20.

Authors

François Nkinahamira¹, Alaaeddin Alsbaiee², Qiaoting Zeng³, Yan Li¹, Yiqing Zhang¹, Meiling Feng⁴, Chang-Ping Yu⁵, Qian Sun⁶

Affiliations

¹ CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, China; University of Chinese Academy of Sciences, China.
² Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA.
³ CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, China.
⁴ State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, China.
⁵ CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, China; Graduate Institute of Environmental Engineering, National Taiwan University, Taiwan.
⁶ CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, China. Electronic address: qsun@iue.ac.cn.

PMID: 32497755
DOI: 10.1016/j.watres.2020.115857

Abstract

Recovery of rare earth elements (REEs) from industrial wastewater has drawn great attention due to their potential environmental toxicity, as well as their high demand in modern technologies. In this study, we developed a magnetic composite based on the high surface area porous β-cyclodextrin polymer (P-CDP), namely P-CDP@Fe₃O₄. Both P-CDP and P-CDP@Fe₃O₄ rapidly sequester REEs such as Nd, Gd, Eu, and Y, reaching equilibrium in less than 10 min and fitting the Langmuir isotherm model with maximum adsorption capacities ranging from 7.76 to 9.59 mg/g at 25 °C when the highest initial concentration was 100 mg/L. Besides, the recovery of these REEs was not affected by competitive alkali, alkaline earth, and transition metal ions in model studies and industrial wastewater as revealed by the recovery efficiencies, which ranged from 62% to 100% indicating an excellent selectivity on both adsorbents. In addition, both adsorbents can be fully regenerated under mildly acidic conditions for at least five consecutive cycles. Moreover, P-CDP@Fe₃O₄ can be easily isolated by an external magnetic field which simplifies its synthesis and usability. It also overcomes the clogging and high backpressure issues of P-CDP, which facilitates its application for REEs recovery as compared with P-CDP. These characteristics demonstrate the promise of P-CDP and P-CDP@Fe₃O₄ for the pollution control and recovery of REEs.

Keywords: Adsorption; Magnetic composite; Rare earth elements (REEs); Recovery; Selectivity.

MeSH terms

Magnetic Phenomena
Polymers
Porosity
Wastewater*
beta-Cyclodextrins*

Substances

Polymers
Waste Water
beta-Cyclodextrins