Phosphogypsum conversion under conditions of SC-CO2

Tokpayev, Rustam; Khavaza, Tamina; Ibraimov, Zair; Kishibayev, Kanagat; Atchabarova, A. A.; Abdimomyn, Saken; Abduakhytova, Dinara; Nauryzbayev, Mikhail

doi:10.1016/j.jcou.2022.102120

Cited by 5 publications

(6 citation statements)

References 31 publications

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“…Additionally, bending vibrations of [OH -] in water molecules and vibrations of water molecules themselves are detected at 3480 cm −1 and 1640 cm −1[30,31], indicating significant amounts of free and bound water in the adsorption products. Characteristic peaks of hydrocerussite at 1410 cm −1 and 685 cm −1 are observed in P-CSH/Pb and P-CSH/Pb+Cd samples, while peaks for otavite are found at 869 cm −1 and 834 cm −1[52,53], corroborating with the XRD findings presented in Figure9.Figure12bdisplays the29 Si MAS NMR spectra of P-CSH before and after adsorption, illustrating notable changes in the chemical environment of Si within the material[35,36,54]. Before adsorption, the Si exhibits a predominant chemical shift at −85.48 ppm, suggesting its configuration predominantly in the form of Qp 2 bridging Si-O tetrahedra.…”

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confidence: 85%

“…Figure 12b displays the 29 Si MAS NMR spectra of P-CSH before and after adsorption, illustrating notable changes in the chemical environment of Si within the material [35,36,54]. Before adsorption, the Si exhibits a predominant chemical shift at −85.48 ppm, suggesting its configuration predominantly in the form of Qp 2 bridging Si-O tetrahedra.…”

Section: Adsorption Mechanismmentioning

confidence: 99%

“…Changes in the surface functional groups of the solid samples were analyzed using Fourier-Transform Infrared Spectroscopy (FT-IR, Nicolet 670, Madison, USA) within a wavenumber range of 400-4000 cm −1 . Finally, high-resolution Solid-State Nuclear Magnetic Resonance (MAS NMR, AVANCE II 400M, Bruker, Switzerland) was used to explore the 29 Si MAS NMR spectra of P-CSH before and after adsorption, utilizing a 4 mm probe and a spinning rate of 10 kHz.…”

Section: Characterizationmentioning

confidence: 99%

“…This research comprehensively explored the adsorption kinetics, isotherms, and the impact of both competitive or synergistic adsorption, as well as the presence of coexisting ions on the performance of P-CSH in capturing Pb(II) and Cd(II). Detailed analyses utilizing XRD, SEM-EDS, FT-IR, and 29 Si MAS NMR characterization methods elucidated the adsorption mechanisms. By converting phosphogypsum into a high-performance adsorbent, this study achieved the dual objectives of "waste treating waste" and "turning waste into treasure", offering innovative strategies for the resourceful use of phosphogypsum and the remediation of heavy metalcontaminated wastewater.…”

Section: Introductionmentioning

confidence: 99%

“…Figure 12. (a) FT-IR spectra of P-CSH and adsorption products following both individual and simultaneous adsorptions of Pb(II) and Cd(II); (b)29 Si MAS NMR spectra of P-CSH before and after adsorption.…”

mentioning

confidence: 99%

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Conversion of Phosphogypsum into Porous Calcium Silicate Hydrate for the Removal and Recycling of Pb(II) and Cd(II) from Wastewater

Wang,

Chen,

et al. 2024

Molecules

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The discharge of lead and cadmium wastewater, along with the pollution caused by phosphogypsum, represents a particularly urgent environmental issue. This study employed a straightforward hydrothermal method to convert phosphogypsum into porous calcium silicate hydrate (P-CSH), which was then used to remove and recover Pb(II) and Cd(II) from wastewater. The adsorption capacities of P-CSH for Pb(II) and Cd(II) were notably high at 989.3 mg/g and 290.3 mg/g, respectively. The adsorption processes adhered to the pseudo-second-order kinetics model and the Langmuir isotherm model. Due to identical adsorption sites on P-CSH for both Pb(II) and Cd(II), competitive interaction occurred when both ions were present simultaneously. Additionally, the adsorption efficacy was minimally impacted by the presence of common coexisting cations in wastewater. The dominant mechanisms for removing Pb(II) and Cd(II) via P-CSH were chemical precipitation and surface complexation. Moreover, the adsorbed heavy metals were efficiently separated and reclaimed from the wastewater through a stepwise desorption process. The primary components of the residue from stepwise desorption were quartz and amorphous SiO2. Following dissolution via pressurized alkaline leaching, this residue could be recycled for synthesizing P-CSH. This research offered a new strategy for the resourceful use of phosphogypsum and heavy metal wastewater.

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