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Mineral Sorbents
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Mineral Sorbents

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Mineral Processing and Extractive Metallurgy".

Deadline for manuscript submissions: closed (20 April 2020) | Viewed by 102477

Special Issue Editor

Prof. Dr. Dorota Kołodyńska

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Guest Editor
Department of Inorganic Chemistry, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie Skłodowska University, 20-031 Lublin, Poland
Interests: ion exchangers; active carbons; biochars; mineral sorbents; zeolites; low-cost sorbents; hybrid materials; heavy metal ions; sorption; removal; separation; environmental protection
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Mineral sorbents are substances of wide application and of great importance for many industrial and environmental technologies. Natural varieties of minerals, mineral waste materials formed as a result of exploitation of, for example, carbonate rocks, or generated in combustion processes in fossil carbons are alternative materials for improving the natural environment.

Due to the unique physicochemical properties, their increasing importance in the processes of toxic compound removal; the reclamation of degraded areas; and the improvement of soil properties, i.e., the restoration of the biogeochemical balance of the environment, is observed year by year. Their unquestionable advantage is that they are cheap and available. Therefore, modified mineral sorbents as catalysts are used in the petrochemical industry. They are also widely applied in the food industry, agriculture, animal husbandry, as well as in medicine for the production of some drugs, etc.

Their use is mostly affected by mineralogical characteristics and unique physicochemical properties as well as simple modifications to enhance their effectiveness by among others grafting, change of surface charge, or structure adjustment. Therefore, all attempts to search for and modify this type of sorbents are of great importance. Their results form the basis for the identification of new physicochemical properties that determine, among others, sorption properties constituting an enormous application potential.

Therefore, this Special Issue aims at publishing papers discussing the recent achievements in the determination of mineral and chemical compositions, structure, and texture; and the adsorption properties of mineral sorbents and their modification to obtain materials for potential applications in environmental protection, especially for the removal of heavy metal ions, dyes, pesticides, etc.

Prof. Dr. Dorota Kołodyńska
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Minerals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • mineral sorbents
  • heavy metals
  • toxic substances
  • layered structure
  • adsorption
  • removal
  • environment

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Published Papers (13 papers)

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Research

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13 pages, 3972 KiB  
Article
Coke-Based Carbon Sorbent: Results of Gold Extraction in Laboratory and Pilot Tests
by Svetlana Yefremova, Alma Terlikbayeva, Abdurassul Zharmenov, Askhat Kablanbekov, Lara Bunchuk, Larissa Kushakova, Viktor Shumskiy, Yurij Sukharnikov and Sergey Yermishin
Minerals 2020, 10(6), 508; https://0-doi-org.brum.beds.ac.uk/10.3390/min10060508 - 31 May 2020
Cited by 5 | Viewed by 2913
Abstract
Coke-based carbon sorbent (CBCS) was produced using special coke fines with the following characteristics: ash, 4.5%; iodine adsorption capacity, 52%; specific surface area, 600 m2 g−1; and total pore volume, 0.4 cm3 g−1. Gold adsorption from real [...] Read more.
Coke-based carbon sorbent (CBCS) was produced using special coke fines with the following characteristics: ash, 4.5%; iodine adsorption capacity, 52%; specific surface area, 600 m2 g−1; and total pore volume, 0.4 cm3 g−1. Gold adsorption from real production cyanide solutions in batch and column laboratory experiments was studied. The optimum adsorbent/solution ratio was 0.2 g/20 cm3. Sorption equilibrium occurred after 60 min of phase-time contact. The CBCS maximum adsorption capacity for gold was found to be 1.2 mg g−1. Both the Langmiur and Freundlich isotherm models confirmed that gold adsorption by CBCS proceeds favorably, but the Freundlich isotherm best describes the adsorption equilibrium. The CBCS dynamic exchange capacity (100 g t−1) and full dynamic exchange capacity (4600 g t−1) for gold were determined in column tests. It was revealed using SEM that adsorbate was retained in sorbent pores. The possibility of completely eluting gold from CBCS was demonstrated. A CBCS pilot test to recover gold from 200 dm3 of the cyanide solution containing (mg dm−3) 2.6 Au, 0.42 Ag, and 490 Cu was carried out. The total amount of noble metals (Au + Ag) adsorbed was 99.99% and gold ions was 94%. The CBCS maximum adsorption capacity for gold reached 2900 g t−1. Full article
(This article belongs to the Special Issue Mineral Sorbents)
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12 pages, 1003 KiB  
Article
The Impact of Microstructure of Filtration Materials on Its Auto-Activation for Manganese Removal from Groundwater
by Zbysław Dymaczewski, Joanna Falkowska, Angelika Frąckowiak, Joanna Jeż-Walkowiak, Justyna Nawrot, Lidia Dudek and Tomasz Topór
Minerals 2020, 10(6), 502; https://0-doi-org.brum.beds.ac.uk/10.3390/min10060502 - 30 May 2020
Cited by 3 | Viewed by 1686
Abstract
The study investigates the impact of pore structure parameters of three chemically non-active filtration materials on the auto-activation time and the height of the filtration zone for manganese removal from groundwater. At a technical scale, the activation is a long process which may [...] Read more.
The study investigates the impact of pore structure parameters of three chemically non-active filtration materials on the auto-activation time and the height of the filtration zone for manganese removal from groundwater. At a technical scale, the activation is a long process which may require a period of up to three months. The process can be shortened by the use of porous filtration materials. In this study, three filtration materials (silica sand, chalcedonite sand, GAC—granulated activated carbon) were investigated using subcritical nitrogen adsorption and mercury injection capillary pressure measurements. These methods provide a comprehensive evaluation of pore structure parameters, including specific surface area (SSA), micro- and mesopore volumes, and an extended range of pore size distribution (PSD). The studied materials provided a wide range of micro- and mesopore volumes as well as SSA. In order to investigate the auto-activation time of filtration material—the time required to achieve the requested quality of the filtrate—and the height of the filtration zone, a pilot experiment was conducted for 1950 h. The pilot installation consisted of three-meters-high (10 cm diameter) filtration columns filled with the tested filtration materials. The results indicate that the internal pore structure and the investigated auto-activation parameters are correlated. Both auto-activation time and the size of the filtration zone were influenced by the mesopore volume and the associated SSA of the tested materials. The micropore volume was less effective in improving the autoactivation parameters. The research results indicated the importance of pore structure characteristics which should be considered prior to time-consuming pilot and technological tests. Full article
(This article belongs to the Special Issue Mineral Sorbents)
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14 pages, 5336 KiB  
Article
Mercury Removal from Aqueous Solutions Using Modified Pyrite: A Column Experiment
by Yucheng Zhu, Shuchuan Peng, Ping Lu, Tianhu Chen and Yan Yang
Minerals 2020, 10(1), 43; https://0-doi-org.brum.beds.ac.uk/10.3390/min10010043 - 31 Dec 2019
Cited by 12 | Viewed by 2987
Abstract
Modified pyrite (MPy), which was obtained from calcination in an N2 atmosphere, was used as a sorbent for removing Hg(II) from aqueous solutions. Fixed-bed column experiments were conducted to determine the Hg(II) removal ability of MPy from aqueous solutions. MPy was found [...] Read more.
Modified pyrite (MPy), which was obtained from calcination in an N2 atmosphere, was used as a sorbent for removing Hg(II) from aqueous solutions. Fixed-bed column experiments were conducted to determine the Hg(II) removal ability of MPy from aqueous solutions. MPy was found to be much better than natural pyrite for mercury removal. The concentration of Hg(II) in effluents was much lower than that of the emission standard used for Hg wastewater in China (0.05 mg/L), and the removal efficiency of Hg(II) was greater than 99% before breakthrough. When the capacity was 3274 times the column bed volume (1 bed volume = 25.12 cm3), the column breakthrough and the sorption amount of Hg(II) were 54.44 mg/g. The Hg(II) content in the used MPy sorbent was up to 24.79%. The mechanism was analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), field emission transmission electron microscopy (FE-TEM), and X-ray Photoelectron Spectroscopy (XPS). The main mechanism of Hg(II) removal by MPy was the chemical reactions between mercury ions and mineral fillers, and HgS precipitated on the surface of MPy to remove Hg(II). The reaction was also accompanied by surface complexation and adsorption. The results of this work show that MPy can be used as a sorbent for continuous Hg(II) removal. Full article
(This article belongs to the Special Issue Mineral Sorbents)
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20 pages, 4107 KiB  
Article
Natural and Chemically Modified Post-Mining Clays—Structural and Surface Properties and Preliminary Tests on Copper Sorption
by Beata Jabłońska, Mark Busch, Andriy V. Kityk and Patrick Huber
Minerals 2019, 9(11), 704; https://0-doi-org.brum.beds.ac.uk/10.3390/min9110704 - 14 Nov 2019
Cited by 11 | Viewed by 2918
Abstract
The structural and surface properties of natural and modified Pliocene clays from lignite mining are investigated in the paper. Chemical modifications are made using hydrofluoric acid (HF), sulfuric acid (H2SO4), hydrochloric acid (HCl), nitric acid (HNO3), sodium [...] Read more.
The structural and surface properties of natural and modified Pliocene clays from lignite mining are investigated in the paper. Chemical modifications are made using hydrofluoric acid (HF), sulfuric acid (H2SO4), hydrochloric acid (HCl), nitric acid (HNO3), sodium hydroxide (NaOH), and hydrogen peroxide (H2O2), at a concentration of 1 mol/dm3. Scanning electron microscopy is used to detect the morphology of the samples. Nitrogen adsorption isotherms were recorded to determine the specific surface area (SSA), mesoporosity, microporosity, and fractal dimensions. The raw clay has an SSA of 66 m2/g. The most promising changes in the structural properties are caused by modifications with HF or H2SO4 (e.g., the SSA increased by about 60%). In addition, the raw and modified clays are used in preliminary tests with Cu(II) sorption, which were performed in batch static method at initial Cu(II) concentrations of 25, 50, 80, 100, 200, 300, and 500 mg/dm3 in 1% aqueous suspensions of the clayey material. The maximum sorption of Cu(II) on the raw material was 15 mg/g. The structural changes after the modifications roughly reflect the capabilities of the adsorbents for Cu(II) adsorption. The modifications with HF and H2SO4 bring a similar improvement in Cu(II) adsorption, which is around 20–25% greater than for the raw material. The structural properties of investigated clays and their adsorptive capabilities indicate they could be used as low-cost adsorbents (e.g., for industrial water pretreatment). Full article
(This article belongs to the Special Issue Mineral Sorbents)
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16 pages, 1921 KiB  
Article
Adsorption Properties of Sepiolite in Relation to Uranium and Lanthanide Ions
by Agnieszka Gładysz-Płaska
Minerals 2019, 9(11), 686; https://0-doi-org.brum.beds.ac.uk/10.3390/min9110686 - 06 Nov 2019
Cited by 7 | Viewed by 2458
Abstract
The batch technique was used to study the adsorption of La(III), Eu(III), Lu(III), and U(VI) ions on sepiolite and ODTMA–sepiolite under ambient conditions. The effects of pH, time, and initial concentration were investigated. The highest U(VI) adsorption was found on ODTMA-sepiolite in the [...] Read more.
The batch technique was used to study the adsorption of La(III), Eu(III), Lu(III), and U(VI) ions on sepiolite and ODTMA–sepiolite under ambient conditions. The effects of pH, time, and initial concentration were investigated. The highest U(VI) adsorption was found on ODTMA-sepiolite in the pH range of 6–8, while in the case of lanthanide ions, adsorption on sepiolite was 80% in the pH range of 4–8 and 98% for pH values above 8. The adsorption capacity of ODTMA-sepiolite was found to be 285.6 mg/g for uranium, and raw sepiolite: 142.8 mg/g for U(VI), 91.6 mg/g for La(III), 91.4 mg/g for Eu (III), and 104.9 mol/g for Lu(III). ODTMA–sepiolite turned out to be a weak sorbent for lanthanide ions. Two short- and long-lived fluorescence species were observed in the TRLFS spectra of U(VI) adsorbed on sepiolite at pH 6.5. The average lifetimes of short- (τ1) and long-lived (τ2) fluorescence are τ1 = 2420 ± 430 ns and τ2 = 37950 ± 5710 ns for U-sepiolite; τ1 = 3523 ± 160 ns and τ2 = 45400 ± 1830 ns for U-ODTMA–sepiolite. Full article
(This article belongs to the Special Issue Mineral Sorbents)
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17 pages, 2308 KiB  
Article
Cesium Sorption and Desorption on Glauconite, Bentonite, Zeolite, and Diatomite
by Petr Belousov, Anna Semenkova, Tolganay Egorova, Anna Romanchuk, Sergey Zakusin, Olga Dorzhieva, Ekaterina Tyupina, Yulia Izosimova, Inna Tolpeshta, Michail Chernov and Victoria Krupskaya
Minerals 2019, 9(10), 625; https://0-doi-org.brum.beds.ac.uk/10.3390/min9100625 - 11 Oct 2019
Cited by 56 | Viewed by 5605
Abstract
This study is devoted to studying the sorption of 137Cs on mineral sorbents at a wide pH range, from 2 to 10, as well as to studying sorption mechanisms. In order to obtain the most reliable sorption characteristics, samples of high purity [...] Read more.
This study is devoted to studying the sorption of 137Cs on mineral sorbents at a wide pH range, from 2 to 10, as well as to studying sorption mechanisms. In order to obtain the most reliable sorption characteristics, samples of high purity were examined as sorbents: bentonite, glauconite, zeolite, and diatomite. A detailed description of their mineral composition, cation exchange capacity and specific surface of sorbents is given. XRD, XRF, FTIR, SEM, and BET adsorption methods were used for assaying. The sorption and desorption values were identified for each sorbent. As a result of the conducted research, it can be concluded that 137Cs sorption mainly occurs through the exchange reaction on zeolite, glauconite and bentonite. The highest cesium Kd was observed on zeolite due to its high CEC and amounted to 4.05 mg/L at pH 7. The higher sorption capacity of glauconite in comparison with bentonite is primarily due to the high layer charge which is mainly localized in tetrahedral sheets, and to the existence of highly selective sorption sites (frayed edge sites) on the glauconite surface. Diatomite showed the lowest sorption capacity provided by the presence of a small quantity of smectite and kaolinite in its composition. The values of desorption increase in the following order: zeolite < bentonite ~ diatomite < glauconite. Full article
(This article belongs to the Special Issue Mineral Sorbents)
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17 pages, 4875 KiB  
Article
Dehydroxylation and Structural Distortion of Kaolinite as a High-Temperature Sorbent in the Furnace
by Yun Cheng, Jingru Xing, Changsheng Bu, Jubing Zhang, Guilin Piao, Yaji Huang, Hao Xie and Xinye Wang
Minerals 2019, 9(10), 587; https://0-doi-org.brum.beds.ac.uk/10.3390/min9100587 - 27 Sep 2019
Cited by 39 | Viewed by 6793
Abstract
As a high-temperature sorbent, kaolinite undergoes the flash calcination process in the furnace resulting in the dehydroxylation and structural distortion, which are closely related to its heavy metal/alkali metal adsorption characteristics. We investigated the flash calcination of kaolinite by the experiments using a [...] Read more.
As a high-temperature sorbent, kaolinite undergoes the flash calcination process in the furnace resulting in the dehydroxylation and structural distortion, which are closely related to its heavy metal/alkali metal adsorption characteristics. We investigated the flash calcination of kaolinite by the experiments using a drop tube furnace and by the characterization of flash-calcined products using thermogravimetric-differential scanning calorimeter (TG-DSC), X-ray diffraction (XRD), Fourier Transform Infrared Spectrometer (FTIR)and nuclear magnetic resonance (NMR). There were three kinds of hydroxyl groups in kaolinite during flash calcination at 800–1300 °C, E-type (~50%, easy), D-type (~40%, difficult) and U-type (~10%, unable) according to the removal difficulty. The hydroxyl groups activation was believed to be the first step of the removal of E-type and D-type hydroxyl groups. The kinetics model of dehydroxylation groups at 900–1200 °C was established following Arrhenius equation with the activation energy of 140 kJ/mol and the pre-exponential factor of 1.32 × 106 s−1. At 800 °C, the removal of E-type hydroxyl groups resulted in the conversion of a part of VI-coordinated Al in kaolinite to V-coordinated Al and the production of meta-kaolinite. When the temperature rose up to 1200 °C, mullite was produced and a part of V-coordinated Al converted to IV-coordinated Al and VI-coordinated Al. Finally, the adsorption characteristics of kaolinite was discussed according to the results of dehydroxylation and structural distortion. Full article
(This article belongs to the Special Issue Mineral Sorbents)
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14 pages, 3547 KiB  
Article
Methylene Blue Adsorption Study on Microcline Particles in the Function of Particle Size Range and Temperature
by Tímea Pernyeszi, Roland Farkas and János Kovács
Minerals 2019, 9(9), 555; https://0-doi-org.brum.beds.ac.uk/10.3390/min9090555 - 15 Sep 2019
Cited by 15 | Viewed by 4718
Abstract
In this paper, the adsorption process of methylene blue has been investigated on microcline particles as a function of particle size and temperature. The characterization of microcline in the particle size ranges of 1−71 μm and 71−315 μm gained by sieving was proved [...] Read more.
In this paper, the adsorption process of methylene blue has been investigated on microcline particles as a function of particle size and temperature. The characterization of microcline in the particle size ranges of 1−71 μm and 71−315 μm gained by sieving was proved using X-ray diffraction (XRD) and scanning electron microscopy combined with energy-dispersive detector (SEM-EDS) in powder form, over laser diffraction measurements in aqueous suspension. The optimum dosage of adsorbent was 13.5 g/L in dye adsorption and the adsorption isotherms on both microcline size fractions were determined at this adsorbent concentration. The maximum adsorption capacities were in the range of 1.5–3.1 mg g−1 on microcline particles with supplementing evaluation of isotherms using the Langmuir model. Considering the problems of linearization of equations, the non-linear least-squares estimation can be strongly recommended for modeling adsorption-equilibrium. The adsorption isotherm determined at elevated temperature of 60−65 °C represents a breakpoint at around 20 mg L−1 of equilibrated dye concentration due to performing of a potential process of dye self-association. According to our experiments, the increase in temperature has an adverse effect on adsorption. Full article
(This article belongs to the Special Issue Mineral Sorbents)
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13 pages, 2460 KiB  
Article
Synthesis of Hydroxy-Sodalite/Cancrinite Zeolites from Calcite-Bearing Kaolin for the Removal of Heavy Metal Ions in Aqueous Media
by Muayad Esaifan, Laurence N. Warr, Georg Grathoff, Tammo Meyer, Maria-Theresia Schafmeister, Angela Kruth and Holger Testrich
Minerals 2019, 9(8), 484; https://0-doi-org.brum.beds.ac.uk/10.3390/min9080484 - 13 Aug 2019
Cited by 39 | Viewed by 5468
Abstract
A hydroxy-sodalite/cancrinite zeolite composite was synthesized from low-grade calcite-bearing kaolin by hydrothermal alkali-activation method at 160 °C for 6 h. The effect of calcite addition on the formation of the hydroxy-sodalite/cancrinite composite was investigated using artificial mixtures. The chemical composition and crystal morphology [...] Read more.
A hydroxy-sodalite/cancrinite zeolite composite was synthesized from low-grade calcite-bearing kaolin by hydrothermal alkali-activation method at 160 °C for 6 h. The effect of calcite addition on the formation of the hydroxy-sodalite/cancrinite composite was investigated using artificial mixtures. The chemical composition and crystal morphology of the synthesized zeolite composite were characterized by X-ray powder diffraction, infrared spectroscopy, scanning electron microscopy, and N2 adsorption/desorption analyses. The average specific surface area is around 17–20 m2·g−1, whereas the average pore size lies in the mesoporous range (19–21 nm). The synthesized zeolite composite was used as an adsorbent for the removal of heavy metals in aqueous solutions. Batch experiments were employed to study the influence of adsorbent dosage on heavy metal removal efficiency. Results demonstrate the effective removal of significant quantities of Cu, Pb, Ni, and Zn from aqueous media. A comparative study of synthesized hydroxy-sodalite and hydroxy-sodalite/cancrinite composites revealed the latter was 16–24% more efficient at removing heavy metals from water. The order of metal uptake efficiency for these zeolites was determined to be Pb > Cu > Zn > Ni. These results indicate that zeolite composites synthesized from natural calcite-bearing kaolin materials could represent effective and low-cost adsorbents for heavy metal removal using water treatment devices in regions of water shortage. Full article
(This article belongs to the Special Issue Mineral Sorbents)
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23 pages, 4691 KiB  
Article
Organo-Modified Vermiculite: Preparation, Characterization, and Sorption of Arsenic Compounds
by Magdalena Tuchowska, Magdalena Wołowiec, Agnieszka Solińska, Anita Kościelniak and Tomasz Bajda
Minerals 2019, 9(8), 483; https://0-doi-org.brum.beds.ac.uk/10.3390/min9080483 - 12 Aug 2019
Cited by 13 | Viewed by 4581
Abstract
Among the various technologies tested for removing the anionic species resulting from arsenic contamination, sorption methods have received unflagging interest. Being potential sorbent materials, clay minerals modified by cationic surfactants are often examined for this purpose. Among the clay minerals tested, information regarding [...] Read more.
Among the various technologies tested for removing the anionic species resulting from arsenic contamination, sorption methods have received unflagging interest. Being potential sorbent materials, clay minerals modified by cationic surfactants are often examined for this purpose. Among the clay minerals tested, information regarding sorption properties of expanded vermiculite modified with surfactants is scarce. Therefore, the present study aims to prepare organo-vermiculites modified with hexadecyltrimethylammonium (HDTMA) and benzyldimethylhexadecylammonium (HDBA) at surfactant concentrations of 0.5, 1.0, and 2.0 cation exchange capacity. Modified sorbents were identified and characterized using the analytical methods that can determine phase composition and textural properties of the samples. The sorption of As(III) and As(V) as a function of initial pH value, initial concentration of As(III, V), and initial dosage of sorbent was investigated. The results show that HDTMA and HDBA affect the properties of raw vermiculite. For instance, increase in the concentration of surfactants is often accompanied by a change in interlayer space or textural properties of vermiculite. It was observed that tested organo-minerals adsorbed As(V) to a greater extent compared to As(III). Various analytical studies were carried out and the results revealed the successful synthesis of organo-vermiculite. Moreover, the study also showed that the structure of organo-vermiculite has a significant impact on the uptake of As(III) and As(V) anions. Full article
(This article belongs to the Special Issue Mineral Sorbents)
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10 pages, 1958 KiB  
Article
Ammonium Sorption from Landfill Leachates Using Natural and Modified Zeolites: Pre-Tests for a Novel Application of the Ion Exchanger Loop Stripping Process
by Daniel Vollprecht, Sabrina Frühauf, Kristina Stocker and Markus Ellersdorfer
Minerals 2019, 9(8), 471; https://0-doi-org.brum.beds.ac.uk/10.3390/min9080471 - 31 Jul 2019
Cited by 14 | Viewed by 3344
Abstract
Ammonium (NH4+) is a main constituent of landfill leachates (50–2200 mg L−1) which has to be removed prior to indirect (<200 mg L−1) or direct discharge (<10 mg L−1) during landfill operation and aftercare, [...] Read more.
Ammonium (NH4+) is a main constituent of landfill leachates (50–2200 mg L−1) which has to be removed prior to indirect (<200 mg L−1) or direct discharge (<10 mg L−1) during landfill operation and aftercare, i.e., for more than 100 years after the end of waste disposal. In this study, lab-scale experiments regarding the sorption of NH4+ from landfill leachates using natural and modified clinoptilolite (Ca0.5,Na,K)6(Al6Si30)O72·20H2O) were conducted to assess the applicability of the innovative ion exchanger loop stripping (ILS) process for ammonium recovery. Samples of 20 g clinoptilolite after different pre-treatments (Ca loading, Na loading, natural loading) were shaken with 500 mL of each leachate from ten Austrian landfills (75 mg L−1 < c(NH4+) < 2805 mg L−1; 7.7 < pH < 8.7) for 24 h. Between 13% and 61% of the dissolved NH4+ was adsorbed to the clinoptilolite, which remained stable during the experiment. In summary, our study indicates that the ILS process is highly promising with respect to NH4+ recovery from landfill leachates, but further research is needed to reach threshold values for direct discharge. Full article
(This article belongs to the Special Issue Mineral Sorbents)
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19 pages, 3841 KiB  
Article
Mono and Poly-Cationic Adsorption of Heavy Metals Using Natural Glauconite
by Małgorzata Franus, Lidia Bandura and Jarosław Madej
Minerals 2019, 9(8), 470; https://0-doi-org.brum.beds.ac.uk/10.3390/min9080470 - 31 Jul 2019
Cited by 15 | Viewed by 3676
Abstract
The issue of heavy metal pollution of industrial wastewaters is a major environmental concern nowadays. The aim of this study was to investigate the effectiveness of heavy metals removal from aqueous solutions by natural glauconite, in batch and dynamic systems. Glauconite was characterized [...] Read more.
The issue of heavy metal pollution of industrial wastewaters is a major environmental concern nowadays. The aim of this study was to investigate the effectiveness of heavy metals removal from aqueous solutions by natural glauconite, in batch and dynamic systems. Glauconite was characterized by X-ray diffraction, nitrogen adsorption–desorption isotherm, scanning electron microscope, differential thermal analysis, and inductively coupled plasma spectroscopy. Cation exchange capacity, bulk density and point of zero charge were also determined. In the batch system, the impact of initial concentration, contact time, and pH of metal solutions on sorption efficiency was analysed, whereas for the dynamic system, the influence of flow rate was studied. The adsorption capacity in the batch system followed the order: Pb > Cd > Zn > Cu. The highest adsorption rate was achieved in the pH range 7–9. In the column experiments, the selectivity order in the case of mono-cationic system was the same as that of batch system, whereas in the case of poly-cationic system it was: Pb > Zn > Cd > Cu. With the increase of the flow rate, the total capacity at the exhaustion point increased. Full article
(This article belongs to the Special Issue Mineral Sorbents)
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17 pages, 737 KiB  
Review
Removal of Heavy Metals and Metalloids from Water Using Drinking Water Treatment Residuals as Adsorbents: A Review
by Magdalena Wołowiec, Małgorzata Komorowska-Kaufman, Alina Pruss, Grzegorz Rzepa and Tomasz Bajda
Minerals 2019, 9(8), 487; https://0-doi-org.brum.beds.ac.uk/10.3390/min9080487 - 14 Aug 2019
Cited by 135 | Viewed by 53844
Abstract
Heavy metal contamination is one of the most important environmental issues. Therefore, appropriate steps need to be taken to reduce heavy metals and metalloids in water to acceptable levels. Several treatment methods have been developed recently to adsorb these pollutants. This paper reviews [...] Read more.
Heavy metal contamination is one of the most important environmental issues. Therefore, appropriate steps need to be taken to reduce heavy metals and metalloids in water to acceptable levels. Several treatment methods have been developed recently to adsorb these pollutants. This paper reviews the ability of residuals generated as a by-product from the water treatment plants to adsorb heavy metals and metalloids from water. Water treatment residuals have great sorption capacities due to their large specific surface area and chemical composition. Sorption capacity is also affected by sorption conditions. A survey of the literature shows that water treatment residuals may be a suitable material for developing an efficient adsorbent for the removal of heavy metals and metalloids from water. Full article
(This article belongs to the Special Issue Mineral Sorbents)
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