Abstract
Abstract: As a recycled material, flue gas desulfurization gypsum has been used to prepare calcium sulfate hemihydrate whisker (CSHW) through hydrothermal synthesis for several decades. However, the subsequent utilization of this resultant material has not yet received considerable attention. In the present research, CSHW was successfully synthesized at a certain region, and was used for the adsorption of lead ions from aqueous solutions, thereby broadening the research field for the practical application of CSHW. Its adsorption capacity was significantly influenced by various parameters, particularly, the pH level and initial lead concentration. The pH value highly affected the hydrolysis degree of lead ions and dominated the adsorption of lead. The equilibrium isotherms under two different temperatures were simulated using Langmuir, Freundlich, and Temkin models. Both Langmuir and Temkin models showed a good fit to the data. Combined with the well-fitted pseudo-second-order model, the adsorption mechanism was thought to be a chemisorption process that was enforced by the ion exchange reaction. In addition, the specific crystal structure of CSHW revealed that ion exchange reaction occurred on the (010) and (100) facets due to their preferential growth and negatively charged property. The residual solid phase after adsorption was collected and detected using X-ray diffraction and scanning electron microscopy with energy dispersive X-ray spectroscopy. Results revealed that PbSO4 was formed on the surface of CSHW. The alkaline condition introduced the tribasic lead sulfate, and thus reduced the stability of the adsorption system.
Highlights
Wet limestone–gypsum wet flue gas desulfurization (WFGD) has already been recognized as a relatively mature and efficient desulfurization technology for FGD treatment, and its actual application rate is approximately 90% worldwide [1]
calcium sulfate hemihydrate whisker (CSHW) was successfully prepared from FGD gypsum through hydrothermal synthesis under the atmospheric pressure
The calcium sulfate hemihydrate whisker was considered as a favorable adsorbent for lead uptake in aqueous solutions
Summary
Wet limestone–gypsum wet flue gas desulfurization (WFGD) has already been recognized as a relatively mature and efficient desulfurization technology for FGD treatment, and its actual application rate is approximately 90% worldwide [1]. Adsorption technology exhibits sufficient advantages, such as easy operation, low cost, secondary pollution-free, and extensive application scope Some natural materials, such as active carbon, kaolin, olive cake, sawdust, and fly ash, may serve as cost-effective sorbents for lead adsorption [24,26]. Gypsum-based materials, such as CSHW, received considerable attention as alternative absorbents in the field of environmental governance This material possesses great potential value in research and application, due to the remarkable characteristics of its crystal surface and chemical components. The absorption performance was characterized and contrasted by data fitting using equilibrium isotherms and kinetic models, and the mechanism was proposed in detail
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
