Comparison of adsorption affinity of ionic polyacrylamide for the surfaces of selected metal oxides

Wiśniewska, Małgorzata; Chibowski, S.; Urban, Teresa

doi:10.1177/0263617417702385

Cited by 9 publications

(6 citation statements)

References 29 publications

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“…The decrease in the negative σ 0 values in the chromium anion presence was noted in the whole examined pH range (3)(4)(5)(6)(7)(8)(9). Based on the site-binding model (Wiśniewska et al 2017), the above phenomenon is associated with interaction of chromium(VI) ions with the kaolinite surface groups resulting in the creation of additional number of positively charged surface sites.…”

Section: Kaolinite Characteristicsmentioning

confidence: 99%

Chromium(VI) reduction and accumulation on the kaolinite surface in the presence of cationic soil flocculant

et al. 2020

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Purpose Heavy metal soluble forms pose a threat to plants, soil microflora, and microfauna. To limit their toxicity and mobility, various immobilizing additives are being developed. The main aim of the study was to determine the influence of soil flocculant (cationic polyacrylamide (CtPAM)) on the hexavalent chromium ion reduction and accumulation on the kaolinite surface. In this way, the efficiency of the selected polymer conditioner in the soil remediation was determined. Materials and methods The adsorbed amounts of Cr(VI) and CtPAM on the kaolinite surface was determined spectrophotometrically (spectrophotometer UV/Vis) using specific indicators. The structure of electrical double layer formed on the kaolinite surface in the mixed system of cationic polyacrylamide and Cr(VI) ions was described based on the adsorptive measurements, zeta potential measurements, as well as potentiometric titration. The kaolinite aggregation in the presence of CtPAM and/or Cr(VI) ions was determined spectrophotometrically and proved using SEM microscopy. The reduction process of Cr(VI) to Cr(III) occurring in the adsorption layer was determined by diffuse reflectance spectroscopy (DRS). Results and discussion The obtained results indicated that cationic polyacrylamide contributes to Cr(VI) reduction to Cr(III) form in the kaolinite suspension. This heavy metal ions are strongly adsorbed by the applied clay mineral, especially at pH 5 (then the Cr(VI)-adsorbed amount equals 5.42 mg/g). The CtPAM addition favors the Cr(VI) ion immobilization on the kaolinite surface. In the conditioner presence, the heavy metal-adsorbed amount is even at 7.34 mg/g. The adsorption of CtPAM and chromium(VI) ions induces changes in the kaolinite surface charge density and electrokinetic potential. What is more, both substances favors the kaolinite aggregation. Conclusions Cationic polyacrylamide may be considered a substance reducing the toxicity of chromium(VI) ions in the natural environment and decreasing their availability for soil organisms. It can improve the soil structure (by stimulating aggregation) and reduce environment pollution with heavy metals simultaneously.

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Section: Kaolinite Characteristicsmentioning

confidence: 99%

Chromium(VI) reduction and accumulation on the kaolinite surface in the presence of cationic soil flocculant

et al. 2020

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“…This electrostatic effect can explain our observed faster Na 2 SO 4 permeation through the AlO x membranes compared to CaCl 2 (i.e., lower NaCl/Na 2 SO 4 selectivity compared to NaCl/CaCl 2 selectivity in Fig. 3c), as AlO x is positively charged at the experimental pH (5.7) 42,43 . Nevertheless, an 8.6-time-higher NaCl flux was observed compared to Na 2 SO 4 flux, suggesting that electrostatic interaction is not the dominant mechanism contributing to the observed selective ion transport.…”

Section: Transport and Separation Properties Of The Aluminum Oxide Me...mentioning

confidence: 82%

Ceramic thin-film composite membranes with tunable subnanometer pores for molecular sieving

Zhou,

Shevate,

Huang

et al. 2023

Nat Commun

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Ceramic membranes are a promising alternative to polymeric membranes for selective separations, given their ability to operate under harsh chemical conditions. However, current fabrication technologies fail to construct ceramic membranes suitable for selective molecular separations. Herein, we demonstrate a molecular-level design of ceramic thin-film composite membranes with tunable subnanometer pores for precise molecular sieving. Through burning off the distributed carbonaceous species of varied dimensions within hybrid aluminum oxide films, we created membranes with tunable molecular sieving. Specifically, the membranes created with methanol showed exceptional selectivity toward monovalent and divalent salts. We attribute this observed selectivity to the dehydration of the large divalent ions within the subnanometer pores. As a comparison, smaller monovalent ions can rapidly permeate with an intact hydration shell. Lastly, the flux of neutral solutes through each fabricated aluminum oxide membrane was measured for the demonstration of tunable separation capability. Overall, our work provides the scientific basis for the design of ceramic membranes with subnanometer pores for molecular sieving using atomic layer deposition.

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“…Increase of this parameter is common behaviour observed in the case of small anion adsorption (such as chromium(VI) anions). Their interactions with the solid hydroxyl groups result in creation of the additional number of positively charged surface sites and the σ 0 value increases (Janusz 1999;Wiśniewska et al 2017). In the adsorption systems containing CT PAM and Cr(VI) the montmorillonite pH pzc parameter is similar to that of the polymer containing system.…”

Section: Electrokinetic Properties Of Montmorillonite Particles Withomentioning

confidence: 99%

Comparison of adsorption affinity of anionic and cationic polyacrylamides for montmorillonite surface in the presence of chromium(VI) ions

et al. 2018

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Erosion, which is considered to be global problem, is the process of soil environment degradation due to the impact of wind (soil blowing, deflation) and water (soil washing, deep erosion). This leads to destruction of its structure, nutrients removal and finally bedrock exposition and desertification. One of the ways to prevent this phenomenon is the soil conditioners usage. These substances, also called soil flocculants, are macromolecular compounds which contribute to the reinforcement of soil structure as a result of its adsorption on the mineral surface. The soil conditioners commonly used in agriculture is ionic polyacrylamide (PAM)-both anionic and cationic. These macromolecular substances affect soil surface properties and adsorption behaviour of substances present in the environment-nutrients, organic molecules and also hazardous compounds as well as toxic heavy metals (i.e. chromium(VI) ions). The aim of this study was to investigate the impact of solution pH, type of ionic groups in the polyacrylamide macromolecules and chromium(VI) ion concentration on the adsorption mechanism of Cr(VI) and PAM on the montmorillonite surface. The adsorption and electrokinetic properties of the montmorillonite-AN PAM or CT PAM/Cr(VI) systems were examined by means of spectrophotometry, potentiometric titration, SEM, XRD and DRS methods. It was shown that in the adsorbed layer composed of PAM-Cr(VI) complexes reduction of Cr(VI) to Cr(III) takes place.

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Comparison of adsorption affinity of ionic polyacrylamide for the surfaces of selected metal oxides

Cited by 9 publications

References 29 publications

Chromium(VI) reduction and accumulation on the kaolinite surface in the presence of cationic soil flocculant

Chromium(VI) reduction and accumulation on the kaolinite surface in the presence of cationic soil flocculant

Ceramic thin-film composite membranes with tunable subnanometer pores for molecular sieving

Comparison of adsorption affinity of anionic and cationic polyacrylamides for montmorillonite surface in the presence of chromium(VI) ions

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