Ultrafast and highly efficient Cd(II) and Pb(II) removal by magnetic adsorbents derived from gypsum and corncob: Performances and mechanisms

Yang, Yuhong; Han, Tongtong; Wang, Jing

doi:10.1016/j.ecoenv.2024.116265

Cited by 3 publications

(1 citation statement)

References 53 publications

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“…Consequently, pollution involving both Pb(II) and Cd(II) is commonly reported [ 4 , 6 , 7 ]. Various methods have been deployed to extract heavy metals from wastewater, such as chemical precipitation [ 8 ], coagulation [ 9 ], electrochemical techniques [ 10 ], membrane filtration [ 11 ], and adsorption [ 12 ]. Of these, adsorption is particularly noteworthy due to its cost-effectiveness, low-energy-requirement, high removal efficiency, and capability to recover heavy metals from wastewater [ 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

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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Section: Introductionmentioning

confidence: 99%

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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A Review of Fluoride Removal from Phosphorous Gypsum: A Quantitative Analysis via a Machine Learning Approach

Jin,

Wang,

et al. 2024

Materials

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This review comprehensively explores fluoride removal from phosphogypsum, focusing on its composition, fluorine-containing compounds, characterization methods, and defluorination techniques. It initially outlines the elemental composition of phosphogypsum prevalent in major production regions and infers the presence of fluorine compounds based on these constituents. The study highlights X-ray photoelectron spectroscopy (XPS) as a pivotal method for characterizing fluorine compounds, emphasizing its capability to determine precise binding energies essential for identifying various fluorine species. Additionally, the first-principle density functional theory (DFT) is employed to estimate binding energies of different fluorine-containing compounds. Significant correlations are observed between the total atomic energy of binary fluorides (e.g., of alkali metals, earth metals, and boron group metals) and XPS binding energies. However, for complex compounds like calcium fluorophosphate, correlations with the calculated average atomic total energy are less direct. The review categorizes defluorination methods applied to phosphogypsum as physical, chemical, thermal, and thermal-combined processes, respectively. It introduces neural network machine learning (ML) technology to quantitatively analyze and optimize reported defluorination strategies. Simulation results indicate potential optimizations based on quantitative analyses of process conditions reported in the literature. This review provides a systematic approach to understanding the phosphogypsum composition, fluorine speciation, analytical methodologies, and effective defluorination strategies. The attempts of adopting DFT simulation and quantitative analysis using ML in optimization underscore its potential and feasibility in advancing the industrial phosphogypsum defluorination process.

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Aniline-p-Phenylenediamine Copolymer for Removal of Hexavalent Chromium from Wastewater

Li,

Chen,

Tan

et al. 2024

Separations

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Hexavalent chromium, one of the heavy metal pollutants in water, harms the ecological environment and human health. In this work, an aniline-p-phenylenediamine copolymer has been prepared by chemical oxidative polymerization to remove the hexavalent chromium (Cr(VI)) from wastewater. The results show that when the initial Cr(VI) concentration is 1.5 mg·L−1, the removal percentage (RP%) of Cr(VI) could reach 94.84% after 180 s of treatment. The RP% of Cr(VI) increases with the dosage of copolymers and decreases with an increase in the initial Cr(VI) concentration. Additionally, the RP% of Cr(VI) removal reaches a maximum of 97.70% with a pH value of 1.0. The Cr(VI) removal kinetics of the copolymers follows a pseudo-first-order chemical reaction model. The X-ray photoelectron spectroscopy (XPS) results demonstrate that the Cr(VI) removal mechanism by the aniline-p-phenylenediamine copolymer is a redox reaction. The positive value of ΔH° and negative value of ΔG° affirm that the Cr(VI) removal process by aniline-p-phenylenediamine copolymer is endothermic, thermodynamically achievable, and spontaneous.

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Ultrafast and highly efficient Cd(II) and Pb(II) removal by magnetic adsorbents derived from gypsum and corncob: Performances and mechanisms

Cited by 3 publications

References 53 publications

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

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

A Review of Fluoride Removal from Phosphorous Gypsum: A Quantitative Analysis via a Machine Learning Approach

Aniline-p-Phenylenediamine Copolymer for Removal of Hexavalent Chromium from Wastewater

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