Sustainable Remediation Processes Based on Zeolites

A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Environmental and Green Processes".

Deadline for manuscript submissions: closed (15 February 2021) | Viewed by 24756

Special Issue Editor


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Guest Editor
Institute of Methodologies for Environmental Analysis - National Research Council - IMAA-CNR, 7-00185 Roma, Italy
Interests: zeolite synthesis from wastes and natural sources; processes for the remediation of polluted soils and water; X-ray diffraction methodologies for mineralogical analysis; clay minerals

Special Issue Information

Dear Colleagues,

Zeolites are crystalline hydrated aluminosilicates characterised by a three-dimensional network of tetrahedral (Si,Al)O4 units that form a system of interconnected pores, which makes these minerals very useful in many applications. Natural and synthetic zeolites can be used for mine water remediation and the treatment of acid mine drainage as well as the removal of ammonium from contaminated solutions and heavy metals from polluted water. Several remediation technologies based on zeolites have also been developed in order to clean up contaminated soils. Some techniques lean towards heavy metal immobilization through the addition of these reactive minerals that alter solid-phase partitioning of the metal contaminant, thus reducing their bioavailability.

This Special Issue on “Sustainable Remediation Processes Based on Zeolites” invites research or review papers focused on the development or application of natural and synthetic zeolites for soil and water remediation. It aims to collect manuscripts describing up-to-date advances in remediation processes based on these very useful minerals as well as to show recent experimental works within this area.

Dr. Claudia Belviso
Guest Editor

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Keywords

  • natural and synthetic zeolite
  • environmental risk assessment
  • water and soil remediation
  • organic and inorganic pollution

Published Papers (7 papers)

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Editorial

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3 pages, 190 KiB  
Editorial
Special Issue “Sustainable Remediation Processes Based on Zeolites”
by Claudia Belviso
Processes 2021, 9(12), 2153; https://doi.org/10.3390/pr9122153 - 29 Nov 2021
Viewed by 1063
Abstract
Zeolites are microporous tectosilicates characterized by a three-dimensional network of tetrahedral (Si, Al)O4 units with the general formula: Mx+Ly2+[Al(x+2y)Si1−(x+2y)O2n]·mH2O where M+ and L2+ are monovalent and divalent cations [...] Full article
(This article belongs to the Special Issue Sustainable Remediation Processes Based on Zeolites)

Research

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25 pages, 7045 KiB  
Article
Preparation and Characterization of the Sulfur-Impregnated Natural Zeolite Clinoptilolite for Hg(II) Removal from Aqueous Solutions
by Marin Ugrina, Martin Gaberšek, Aleksandra Daković and Ivona Nuić
Processes 2021, 9(2), 217; https://doi.org/10.3390/pr9020217 - 25 Jan 2021
Cited by 9 | Viewed by 2626
Abstract
Sulfur-impregnated zeolite has been obtained from the natural zeolite clinoptilolite by chemical modification with Na2S at 150 °C. The purpose of zeolite impregnation was to enhance the sorption of Hg(II) from aqueous solutions. Chemical analysis, acid and basic properties determined by [...] Read more.
Sulfur-impregnated zeolite has been obtained from the natural zeolite clinoptilolite by chemical modification with Na2S at 150 °C. The purpose of zeolite impregnation was to enhance the sorption of Hg(II) from aqueous solutions. Chemical analysis, acid and basic properties determined by Bohem’s method, chemical behavior at different pHo values, zeta potential, cation-exchange capacity (CEC), specific surface area, X-ray powder diffraction (XRPD), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), as well as thermogravimetry with derivative thermogravimetry (TG-DTG) were used for detailed comparative mineralogical and physico-chemical characterization of natural and sulfur-impregnated zeolites. Results revealed that the surface of the natural zeolite was successfully impregnated with sulfur species in the form of FeS and CaS. Chemical modification caused an increase in basicity and the net negative surface charge due to an increase in oxygen-containing functional groups as well as a decrease in specific surface area and crystallinity due to the formation of sulfur-containing clusters at the zeolite surface. The sorption of Hg(II) species onto the sulfur-impregnated zeolite was affected by the pH, solid/liquid ratio, initial Hg(II) concentration, and contact time. The optimal sorption conditions were determined as pH 2, a solid/liquid ratio of 10 g/L, and a contact time of 800 min. The maximum obtained sorption capacity of the sulfur-impregnated zeolite toward Hg(II) was 1.02 mmol/g. The sorption mechanism of Hg(II) onto the sulfur-impregnated zeolite involves electrostatic attraction, ion exchange, and surface complexation, accompanied by co-precipitation of Hg(II) in the form of HgS. It was found that sulfur-impregnation enhanced the sorption of Hg(II) by 3.6 times compared to the natural zeolite. The leaching test indicated the retention of Hg(II) in the zeolite structure over a wide pH range, making this sulfur-impregnated sorbent a promising material for the remediation of a mercury-polluted environment. Full article
(This article belongs to the Special Issue Sustainable Remediation Processes Based on Zeolites)
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15 pages, 10013 KiB  
Article
The Potential Use of Zeolite, Montmorillonite, and Biochar for the Removal of Radium-226 from Aqueous Solutions and Contaminated Groundwater
by Fahad I. Almasoud, Abdullah S. Al-Farraj, Mohammad I. Al-Wabel, Adel R.A. Usman, Yousef J. Alanazi and Zaid Q. Ababneh
Processes 2020, 8(12), 1537; https://doi.org/10.3390/pr8121537 - 25 Nov 2020
Cited by 3 | Viewed by 2611
Abstract
The present work investigated the potential of using zeolite (clinoptilolite), montmorillonite (Swy2), and Conocarpus biochar as adsorbents to remove 226Ra from aqueous solution. The effect of the initial 226Ra concentrations on sorbents’ equilibrium activity concentrations and sorbents’ radium removal efficiency were [...] Read more.
The present work investigated the potential of using zeolite (clinoptilolite), montmorillonite (Swy2), and Conocarpus biochar as adsorbents to remove 226Ra from aqueous solution. The effect of the initial 226Ra concentrations on sorbents’ equilibrium activity concentrations and sorbents’ radium removal efficiency were investigated. The results showed that zeolite has a higher removal efficiency for 226Ra in comparison with the efficiencies of montmorillonite and biochar. In addition to the linear isotherm model, the Freundlich model, followed by Temkin’s model, provided a better description of the adsorption process than the Langmuir model. Kinetic studies indicated that a pseudo-second-order kinetic model could be the best fit for the adsorption of 226Ra onto the three investigated sorbents, which suggests that the mechanism of adsorption of 226Ra by sorbents was chemisorption. The intraparticle diffusion model indicated that adsorption of 226Ra onto the sorbents involves a multistep process: (i) boundary layer diffusion and (ii) intraparticle diffusion. Moreover, the remediation of groundwater samples polluted with 226Ra was assessed using the investigated sorbents; the results showed that zeolite also has the highest removal efficiency among other sorbents. Thus, the low cost, availability, and the high adsorption efficiency of zeolite can be a promising sorbent on 226Ra removal from aqueous solutions and groundwater remediation. Full article
(This article belongs to the Special Issue Sustainable Remediation Processes Based on Zeolites)
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12 pages, 1597 KiB  
Article
Nitrogen Recovery from Swine Manure Using a Zeolite-Based Process
by Markus Ellersdorfer, Sandro Pesendorfer and Kristina Stocker
Processes 2020, 8(11), 1515; https://doi.org/10.3390/pr8111515 - 21 Nov 2020
Cited by 6 | Viewed by 2558
Abstract
Intensive pig farming produces huge amounts of swine manure, which can cause regional nutrient imbalances and represent a potential source of soil and water pollution due to manure over-application. In order to improve nutrient stewardship, technologies for manure treatment and selective recovery of [...] Read more.
Intensive pig farming produces huge amounts of swine manure, which can cause regional nutrient imbalances and represent a potential source of soil and water pollution due to manure over-application. In order to improve nutrient stewardship, technologies for manure treatment and selective recovery of nutrients (especially ammonia) have to be developed to foster agriculture–food system sustainability. In the present study, a combined stripping and ion exchange process using natural zeolite (ion-exchanger-loop-stripping process) is tested for nitrogen recovery from swine manure to determine its technical feasibility in this novel field of application. Ammonium removal rates of 85 to 96% were achieved in pilot scale experiments with preprocessed manure (~500 L h−1 after mechanical filtration; input concentration: ~1.3 g NH4+ L−1). NH4+ was successfully transferred to a concentrated ammonium sulfate solution (final concentration: 66 g NH4+ L−1), with no significant transfer of other manure components. Hence, various utilizations of the product solution are possible, e.g., for industrial off-gas cleaning (DeNOx) or as raw material for fertilizer production. Based on these findings, the ILS-process can be regarded as a promising option for nitrogen recovery from swine manure. Full article
(This article belongs to the Special Issue Sustainable Remediation Processes Based on Zeolites)
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19 pages, 4638 KiB  
Article
Studies on the Potential of Nonmodified and Metal Oxide-Modified Coal Fly Ash Zeolites For Adsorption of Heavy Metals and Catalytic Degradation of Organics for Waste Water Recovery
by Silviya Boycheva, Denitza Zgureva, Simona Miteva, Ivan Marinov, Dominika Marcin Behunová, Ivalina Trendafilova, Margarita Popova and Miroslava Václaviková
Processes 2020, 8(7), 778; https://doi.org/10.3390/pr8070778 - 03 Jul 2020
Cited by 16 | Viewed by 3232
Abstract
A nanocrystalline zeolite of Na-X type (CFAZ) was synthesized by ultrasonic-assisted double stage fusion-hydrothermal alkaline conversion of lignite coal fly ash. Modified CFAZ with magnetic nanoparticles (MNP-CFAZ) was obtained by adding presynthesized magnetic nanoparticles between the synthesis stages. CFAZs loaded by particles of [...] Read more.
A nanocrystalline zeolite of Na-X type (CFAZ) was synthesized by ultrasonic-assisted double stage fusion-hydrothermal alkaline conversion of lignite coal fly ash. Modified CFAZ with magnetic nanoparticles (MNP-CFAZ) was obtained by adding presynthesized magnetic nanoparticles between the synthesis stages. CFAZs loaded by particles of copper (Cu-CFAZ) and cobalt (Co-CFAZ) oxides were prepared by postsynthesis modification of the parent CFAZ, applying a wet impregnation technique. The parent and modified CFAZs were examined for their phase composition by X-ray diffraction, morphology by scanning electron microscopy, and surface characteristics by N2 physisorption. Comparative studies have been carried out on the adsorption capacity of the starting CFAZ and its derivatives with respect to Cd2+- and Pb2+-ions from aqueous solutions. Adsorption isotherms of Cd2+-ions on the studied samples were plotted and described by the adsorption equations of Langmuir, Freundlich, Langmuir–Freundlich, and Temkin. The best correlation between the experimental and model isotherms for the parent and modified CFAZ was found with the Langmuir linear model, assuming a monolayer adsorption mechanism. Parent and modified CFAZs were also studied as catalysts for heterogeneous thermal Fenton oxidation of methylene blue. At 90 °C, the higher catalytic activity exhibits the nonmodified sample, but with the decrease in temperature to 60 °C, the modified samples are more effective catalysts. Full article
(This article belongs to the Special Issue Sustainable Remediation Processes Based on Zeolites)
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11 pages, 908 KiB  
Article
A Fractal-Based Correlation for Time-Dependent Surface Diffusivity in Porous Adsorbents
by Vassilis J. Inglezakis, Marco Balsamo and Fabio Montagnaro
Processes 2020, 8(6), 689; https://doi.org/10.3390/pr8060689 - 12 Jun 2020
Cited by 4 | Viewed by 2184
Abstract
Fluid–solid adsorption processes are mostly governed by the adsorbate transport in the solid phase and surface diffusion is often the limiting step of the overall process in microporous materials such as zeolites. This work starts from a concise review of concepts and models [...] Read more.
Fluid–solid adsorption processes are mostly governed by the adsorbate transport in the solid phase and surface diffusion is often the limiting step of the overall process in microporous materials such as zeolites. This work starts from a concise review of concepts and models for surface transport and variable surface diffusivity. It emerges that the phenomenon of hindered surface diffusion for monolayer adsorption, which is common in zeolites, and models able to fit a non-monotonic trend of surface diffusivity against adsorbate solid phase concentration, have received limited attention. This work contributes to the literature of hindered diffusion by formulating a time-dependent equation for surface diffusivity based on fractal dynamics concepts. The proposed equation takes into account the contributions of both fractal-like diffusion (a time-decreasing term) and hopping diffusion (a time-increasing term). The equation is discussed and numerically analyzed to testify its ability to reproduce the possible different patterns of surface diffusivity vs. time. Full article
(This article belongs to the Special Issue Sustainable Remediation Processes Based on Zeolites)
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15 pages, 4545 KiB  
Article
Catalytic Oxidation of Methylene Blue by Use of Natural Zeolite-Based Silver and Magnetite Nanocomposites
by Aldiyar Kuntubek, Nurassyl Kinayat, Kulyash Meiramkulova, Stavros G. Poulopoulos, Joseph C. Bear and Vassilis J. Inglezakis
Processes 2020, 8(4), 471; https://doi.org/10.3390/pr8040471 - 16 Apr 2020
Cited by 12 | Viewed by 4051
Abstract
This work reports the synthesis of natural zeolite-based silver and magnetite nanocomposites and their application for the catalytic oxidation of methylene blue in water. The zeolite was impregnated with 5.5 wt.% Fe in the form of magnetite nanoparticles with size of 32 nm, [...] Read more.
This work reports the synthesis of natural zeolite-based silver and magnetite nanocomposites and their application for the catalytic oxidation of methylene blue in water. The zeolite was impregnated with 5.5 wt.% Fe in the form of magnetite nanoparticles with size of 32 nm, and with 6.4 wt.% Ag in the form of silver oxide and metallic silver nanoparticles with sizes of 42 and 20 nm, respectively. The results showed that physical adsorption contributed to the removal of methylene blue by 25–36% and that Fe3O4@NZU is superior to Ag2O@NZU and Ag0@NZU, leading to 55% removal without oxidant and 97% in the presence of H2O2. However, there is no evidence of significant mineralization of methylene blue. The application of reaction rate models showed that the reaction order changes from zero to first and second order depending on the H2O2 concentration. Full article
(This article belongs to the Special Issue Sustainable Remediation Processes Based on Zeolites)
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