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17 pages, 5052 KiB

Open AccessArticle

Rational Design of Polyamine-Based Cryogels for Metal Ion Sorption

by Irina Malakhova, Yuliya Privar, Yuliya Parotkina, Aleksandr Mironenko, Marina Eliseikina, Denis Balatskiy, Alexey Golikov and Svetlana Bratskaya

Molecules 2020, 25(20), 4801; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25204801 - 19 Oct 2020

Cited by 8 | Viewed by 2212

Abstract

Here we report the method of fabrication of supermacroporous monolith sorbents (cryogels) via covalent cross-linking of polyallylamine (PAA) with diglycidyl ether of 1,4-butandiol. Using comparative analysis of the permeability and sorption performance of the obtained PAA cryogels and earlier developed polyethyleneimine (PEI) cryogels, [...] Read more.

Here we report the method of fabrication of supermacroporous monolith sorbents (cryogels) via covalent cross-linking of polyallylamine (PAA) with diglycidyl ether of 1,4-butandiol. Using comparative analysis of the permeability and sorption performance of the obtained PAA cryogels and earlier developed polyethyleneimine (PEI) cryogels, we have demonstrated the advantages and disadvantages of these polymers as sorbents of heavy metal ions (Cu(II), Zn(II), Cd(II), and Ni(II)) in fixed-bed applications and as supermacroporous matrices for the fabrication of composite cryogels containing copper ferrocyanide (CuFCN) for cesium ion sorption. Applying the rate constant distribution (RCD) model to the kinetic curves of Cu(II) ion sorption on PAA and PEI cryogels, we have elucidated the difference in sorption/desorption rates and affinity constants of these materials and showed that physical sorption contributed to the Cu(II) uptake by PAA, but not to that by PEI cryogels. It was shown that PAA cryogels had significantly higher selectivity for Cu(II) sorption in the presence of Zn(II) and Cd(II) ions in comparison with that of PEI cryogels, while irreversible sorption of Co(II) ions by PEI can be used for the separation of Ni(II) and Co(II) ions. Using IR and Mössbauer spectroscopy, we have demonstrated that strong complexation of Cu(II) ions with PEI significantly affects the in situ formation of Cu(II) ferrocyanide nanosorbents leading to their inefficiency for Cs⁺ ions selective uptake, whereas PAA cryogel was applicable for the fabrication of efficient monolith composites via the in situ formation of CuFCN or loading of ex situ formed CuFCN colloids. Full article

(This article belongs to the Special Issue Application of Sorption Materials in Environment)

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25 pages, 7306 KiB

Open AccessArticle

Recovery of Lanthanum(III) and Nickel(II) Ions from Acidic Solutions by the Highly Effective Ion Exchanger

by Dorota Kołodyńska, Dominika Fila and Zbigniew Hubicki

Molecules 2020, 25(16), 3718; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25163718 - 14 Aug 2020

Cited by 9 | Viewed by 2282

Abstract

The recovery of La(III) and Ni(II) ions by a macroporous cation exchanger in sodium form (Lewatit Monoplus SP112) has been studied in batch experiments under varying HNO₃ concentrations (0.2–2.0 mol/dm³), La(III) and Ni(II) concentrations (25–200 mg/dm³), phase contact [...] Read more.

The recovery of La(III) and Ni(II) ions by a macroporous cation exchanger in sodium form (Lewatit Monoplus SP112) has been studied in batch experiments under varying HNO₃ concentrations (0.2–2.0 mol/dm³), La(III) and Ni(II) concentrations (25–200 mg/dm³), phase contact time (1–360 min), temperature (293–333 K), and resin mass (0.1–0.5 g). The experimental data revealed that the sorption process was dependent on all parameters used. The maximum sorption capacities were found at CHNO₃ = 0.2 mol/dm³, m = 0.1 g, and T = 333 K. The kinetic data indicate that the sorption followed the pseudo-second order and film diffusion models. The sorption equilibrium time was reached at approximately 30 and 60 min for La(III) and Ni(II) ions, respectively. The equilibrium isotherm data were best fitted with the Langmuir model. The maximum monolayer capacities of Lewatit Monoplus SP112 were equal to 95.34 and 60.81 mg/g for La(III) and Ni(II) ions, respectively. The thermodynamic parameters showed that the sorption process was endothermic and spontaneous. Moreover, dynamic experiments were performed using the columns set. The resin regeneration was made using HCl and HNO₃ solutions, and the desorption results exhibited effective regeneration. The ATR/FT-IR and XPS spectroscopy results indicated that the La(III) and Ni(II) ions were coordinated with the sulfonate groups. Full article

(This article belongs to the Special Issue Application of Sorption Materials in Environment)

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16 pages, 2928 KiB

Open AccessArticle

Selection of the Activated Carbon Type for the Treatment of Landfill Leachate by Fenton-Adsorption Process

by Liliana San-Pedro, Roger Méndez-Novelo, Emanuel Hernández-Núñez, Manuel Flota-Bañuelos, Jorge Medina and Germán Giacomán-Vallejos

Molecules 2020, 25(13), 3023; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25133023 - 02 Jul 2020

Cited by 15 | Viewed by 2986

Abstract

Sanitary landfill leachates usually have characteristics that depend on the region where they are generated and according to the age of the landfill, which is why a unique treatment for their sanitation has not been found. However, the adsorption preceded by the Fenton [...] Read more.

Sanitary landfill leachates usually have characteristics that depend on the region where they are generated and according to the age of the landfill, which is why a unique treatment for their sanitation has not been found. However, the adsorption preceded by the Fenton process has been proven to be highly efficient at removing contaminants. In this study, the adsorptive capacity of two types of activated carbon, granular and powdered, was analyzed to determine which was more efficient in the adsorption stage in the Fenton-adsorption process. Likewise, its behavior was analyzed using three isotherm models (Langmuir, Freundlich and Temkin), testing the raw leachate and the Fenton-treated one with both carbons. The adsorption that is carried out on the carbons is better adjusted to the Freundlich and Temkin models. It concludes that multilayers, through the physical adsorption, carry out the adsorption of pollutants on the surface of the carbons. The results show that, statistically, granular activated carbon is more efficient at removing chemical oxygen demand (COD), and powdered activated carbon removes color better. Finally, an adsorption column was designed for the Fenton-adsorption process that was able to remove 21.68 kgCOD/kg carbon. Removal efficiencies for color and COD were >99%. Full article

(This article belongs to the Special Issue Application of Sorption Materials in Environment)

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18 pages, 3652 KiB

Open AccessFeature PaperArticle

A Comparative Study on Cu²⁺, Zn²⁺, Ni²⁺, Fe³⁺, and Cr³⁺ Metal Ions Removal from Industrial Wastewaters by Chitosan-Based Composite Cryogels

by Doina Humelnicu, Ecaterina Stela Dragan, Maria Ignat and Maria Valentina Dinu

Molecules 2020, 25(11), 2664; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25112664 - 08 Jun 2020

Cited by 23 | Viewed by 3823

Abstract

Materials coming from renewable resources have drawn recently an increased attention in various applications as an eco-friendly alternative in the synthesis of novel functional materials. Polysaccharides, with their prominent representative – chitosan (CS), are well-known for their sorption properties, being able to remove [...] Read more.

Materials coming from renewable resources have drawn recently an increased attention in various applications as an eco-friendly alternative in the synthesis of novel functional materials. Polysaccharides, with their prominent representative – chitosan (CS), are well-known for their sorption properties, being able to remove metal ions from dilute solutions either by electrostatic interactions or chelation. In this context, we proposed here a comparative study on Cu²⁺, Zn²⁺, Ni²⁺, Fe³⁺, and Cr³⁺ metal ions removal from industrial wastewaters by CS-based composite cryogels using batch technique. The composite cryogels consisting of CS embedding a natural zeolite, namely clinoptilolite, were synthesized by cryogelation, and their sorption performance were compared to those of CS cryogels and of acid-activated zeolite. A deeper analysis of thermodynamics and kinetics sorption data was performed to get insights into the sorption mechanism of all metal ions onto sorbents. Based on the optimized sorption conditions, the removal of the above-mentioned ions from aqueous solutions by the composite sorbent using dynamic technique was also evaluated. Full article

(This article belongs to the Special Issue Application of Sorption Materials in Environment)

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15 pages, 3161 KiB

Open AccessArticle

Solubility and Selectivity Effects of the Anion on the Adsorption of Different Heavy Metal Ions onto Chitosan

by Janek Weißpflog, Alexander Gündel, David Vehlow, Christine Steinbach, Martin Müller, Regine Boldt, Simona Schwarz and Dana Schwarz

Molecules 2020, 25(11), 2482; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25112482 - 27 May 2020

Cited by 28 | Viewed by 3919

Abstract

The biopolymer chitosan is a very efficient adsorber material for the removal of heavy metal ions from aqueous solutions. Due to the solubility properties of chitosan it can be used as both a liquid adsorber and a solid flocculant for water treatment reaching [...] Read more.

The biopolymer chitosan is a very efficient adsorber material for the removal of heavy metal ions from aqueous solutions. Due to the solubility properties of chitosan it can be used as both a liquid adsorber and a solid flocculant for water treatment reaching outstanding adsorption capacities for a number of heavy metal ions. However, the type of anion corresponding to the investigated heavy metal ions has a strong influence on the adsorption capacity and sorption mechanism on chitosan. In this work, the adsorption capacity of the heavy metal ions manganese, iron, cobalt, nickel, copper, and zinc were investigated in dependence on their corresponding anions sulfate, chloride, and nitrate by batch experiments. The selectivity of the different heavy metal ions was analyzed by column experiments. Full article

(This article belongs to the Special Issue Application of Sorption Materials in Environment)

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19 pages, 2527 KiB

Open AccessFeature PaperArticle

Contribution of Cross-Linker and Silica Morphology on Cr(VI) Sorption Performances of Organic Anion Exchangers Embedded into Silica Pores

by Ecaterina Stela Dragan and Doina Humelnicu

Molecules 2020, 25(5), 1249; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25051249 - 10 Mar 2020

Cited by 9 | Viewed by 2790

Abstract

Removal of Cr(VI) from the environment represents a stringent issue because of its tremendous effects on living organisms. In this context, design of sorbents with high sorption capacity for Cr(VI) is getting a strong need. For this purpose, poly(vinylbenzyl chloride), impregnated into porous [...] Read more.

Removal of Cr(VI) from the environment represents a stringent issue because of its tremendous effects on living organisms. In this context, design of sorbents with high sorption capacity for Cr(VI) is getting a strong need. For this purpose, poly(vinylbenzyl chloride), impregnated into porous silica (PSi), was cross-linked with either N,N,N’,N’-tetramethyl-1,2-ethylenediamine (TEMED) or N,N,N’,N’-tetramethyl-1,3-propanediamine, followed by the reaction of the free -CH₂Cl groups with N,N-diethyl-2-hydroxyethylamine to generate strong base anion exchangers (ANEX) inside the pores. The PSi/ANEX composite sorbents were deeply characterized by FTIR spectroscopy, SEM-energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and water uptake. The sorption performances of composites against Cr(VI) were investigated as a function of pH, contact time, initial concentration of Cr(VI), and temperature. It was found that the cross-linker structure and the silica morphology are the key factors controlling the sorption capacity. The adsorption process was spontaneous and endothermic and well described by pseudo-second-order kinetic and Sips isotherm models. The maximum sorption capacity of 311.2 mg Cr(VI)/g sorbent was found for the composite prepared with mesoporous silica using TEMED as cross-linker. The PSi/ANEX composite sorbents represent an excellent alternative for the removal of Cr(VI) oxyanions, being endowed with fast kinetics, equilibrium in about 60 min, and a high level of reusability in successive sorption/desorption cycles. Full article

(This article belongs to the Special Issue Application of Sorption Materials in Environment)

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24 pages, 2015 KiB

Open AccessArticle

Amidoxime Functionalization of Algal/Polyethyleneimine Beads for the Sorption of Sr(II) from Aqueous Solutions

by Yuezhou Wei, Khalid A. M. Salih, Siming Lu, Mohammed F. Hamza, Toyohisa Fujita, Thierry Vincent and Eric Guibal

Molecules 2019, 24(21), 3893; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules24213893 - 29 Oct 2019

Cited by 40 | Viewed by 3263

Abstract

There is a need for developing new sorbents that incorporate renewable resources for the treatment of metal-containing solutions. Algal-polyethyleneimine beads (APEI) (reinforced with alginate) are functionalized by grafting amidoxime groups (AO-APEI). Physicochemical characteristics of the new material are characterized using FTIR, XPS, TGA, [...] Read more.

There is a need for developing new sorbents that incorporate renewable resources for the treatment of metal-containing solutions. Algal-polyethyleneimine beads (APEI) (reinforced with alginate) are functionalized by grafting amidoxime groups (AO-APEI). Physicochemical characteristics of the new material are characterized using FTIR, XPS, TGA, SEM, SEM-EDX, and BET. AO-APEI beads are tested for the recovery of Sr(II) from synthetic solutions after pH optimization (≈ pH 6). Uptake kinetics is fast (equilibrium ≈ 60–90 min). Sorption isotherm (fitted by the Langmuir equation) shows remarkable sorption capacity (≈ 189 mg Sr g⁻¹). Sr(II) is desorbed using 0.2 M HCl/0.5 M CaCl₂ solution; sorbent recycling over five cycles shows high stability in terms of sorption/desorption performances. The presence of competitor cations is studied in relation to the pH; the selectivity for Sr(II) is correlated to the softness parameter. Finally, the recovery of Sr(II) is carried out in complex solutions (seawater samples): AO-APEI is remarkably selective over highly concentrated metal cations such as Na(I), K(I), Mg(II), and Ca(II), with weaker selectivity over B(I) and As(V). AO-APEI appears to be a promising material for selective recovery of strontium from complex solutions (including seawater). Full article

(This article belongs to the Special Issue Application of Sorption Materials in Environment)

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Review

Jump to: Research

23 pages, 3605 KiB

Open AccessReview

Polymer-Supported Phosphoric, Phosphonic and Phosphinic Acids—From Synthesis to Properties and Applications in Separation Processes

by Agnieszka Głowińska and Andrzej W. Trochimczuk

Molecules 2020, 25(18), 4236; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25184236 - 15 Sep 2020

Cited by 15 | Viewed by 7277

Abstract

Efficient separation technologies are crucial to the environment and world economy. The challenge posed to scientists is how to engineer selectivity towards a targeted substrate, especially from multicomponent solutions. Polymer-supported reagents have gained a lot of attention in this context, as they eliminate [...] Read more.

Efficient separation technologies are crucial to the environment and world economy. The challenge posed to scientists is how to engineer selectivity towards a targeted substrate, especially from multicomponent solutions. Polymer-supported reagents have gained a lot of attention in this context, as they eliminate a lot of inconveniences concerning widely used solvent extraction techniques. Nevertheless, the choice of an appropriate ligand for immobilization may be derived from the behavior of soluble compounds under solvent extraction conditions. Organophosphorus compounds play a significant role in separation science and technology. The features they possess, such as variable oxidation states, multivalence, asymmetry and metal-binding properties, highlight their status as a unique and versatile class of compounds, capable of selective separations proceeding through different mechanisms. This review provides a detailed survey of polymers containing phosphoric, phosphonic and phosphinic acid functionalities in the side chain and covers main advances in the preparation and application of these materials in separation science, including the most relevant synthesis routes (Arbuzov, Perkow, Mannich, Kabachnik-Fields reactions, etc.), as well as the main stages in the development of organophosphorus resins and the most important achievements in the field. Full article

(This article belongs to the Special Issue Application of Sorption Materials in Environment)

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