Structural Evolution of Geopolymers Incorporated with Heavy Metals: Solidification Mechanism of Pb2+ and Cd2+

Wei，Xuankun1,2; Sun，Yongqi3; Su，Yiping1; Shen，Xuehua1; Tang，Yuanyuan1; Yan，Feng1; Zhang，Zuotai1

2023

10.1021/acs.jpcc.3c03924

Journal of Physical Chemistry C   Impact Factor & Quartile

1932-7447

1932-7455

Geopolymers have emerged as a promising solution for solidifying heavy metals; however, the underlying mechanisms remain elusive. In this study, we synthesized geopolymers incorporating Pb and Cd to unravel their solidification mechanisms. Leaching analyses demonstrated superior solidification efficacy for Pb (93.6%) compared to that for Cd (65.2%). The dissimilarity in solidification mechanisms can be attributed to variances in ionic potential and covalent interactions between the cations. Furthermore, Cd exhibited a higher ionic potential, facilitating its exchange with Na in the geopolymer matrix. Triple-quantum nuclear magnetic resonance experiments revealed a weak affinity of the geopolymer structure toward Cd. Density functional theory calculations affirmed stronger interactions between Pb (−8.71 eV) and the matrix compared to those of Cd (−5.83 eV). Consequently, Pb demonstrated an enhanced covalent propensity within the geopolymer matrix, while Cd primarily underwent solidification via ion exchange. This research provides novel insights and concepts regarding the mechanisms involved in solidifying heavy metals in geopolymers.

SCI

English

First ; Corresponding

National Science Fund for Distinguished Young Scholars[52225407] ; Shenzhen Science and Technology Innovation Committee["JCYJ20200109141437586","JCYJ20200109141642225","JCYJ20200109141227141"]

Chemistry ; Science & Technology - Other Topics ; Materials Science

Chemistry, Physical ; Nanoscience & Nanotechnology ; Materials Science, Multidisciplinary

WOS:001051491600001

AMER CHEMICAL SOC

2-s2.0-85170051378

Scopus

1.School of Environmental Science and Engineering,Southern University of Science and Technology,Shenzhen,518055,China
2.College of Engineering,Peking University,Beijing,100871,China
3.School of Metallurgy and Environment and National Center for International Cooperation of Clean Metallurgy,Central South University,Changsha,410083,China

Wei，Xuankun,Sun，Yongqi,Su，Yiping,et al. Structural Evolution of Geopolymers Incorporated with Heavy Metals: Solidification Mechanism of Pb2+ and Cd2+[J]. Journal of Physical Chemistry C,2023,127(39).

Wei，Xuankun.,Sun，Yongqi.,Su，Yiping.,Shen，Xuehua.,Tang，Yuanyuan.,...&Zhang，Zuotai.(2023).Structural Evolution of Geopolymers Incorporated with Heavy Metals: Solidification Mechanism of Pb2+ and Cd2+.Journal of Physical Chemistry C,127(39).

Wei，Xuankun,et al."Structural Evolution of Geopolymers Incorporated with Heavy Metals: Solidification Mechanism of Pb2+ and Cd2+".Journal of Physical Chemistry C 127.39(2023).