Charge reversal and anion effects during adsorption of metal ions at clay surfaces: Mechanistic aspects and influence factors

Huang, Xiaoxiao; Yang, Gang

doi:10.1016/j.chemphys.2019.110575

Cited by 15 publications

(6 citation statements)

References 57 publications

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“…This occurs due to the presence of permanent electrical charges inherent to the minerals present in the clay composition, as with kaolinite and illite present in the Campos dos Goytacazes clays 42,43 . These charges are negative and vary between −1 and −4, 44,45 depending on the chemical and mineralogical composition of the clay and must be stoichiometrically balanced by the positive ions present in the marble residue. The present work proposed a ratio of 1:1, 1:2, and 2:1 (marble:clay) between the moles present in cementitious ceramics to balance the loads between the two residues, resulting in the other compositions illustrated in Table 3.…”

Section: Methodsmentioning

confidence: 99%

Circular economy in cementitious ceramics: Replacement of hydrated lime with a stoichiometric balanced combination of clay and marble waste

Marvila¹,

Azevedo

Alexandre³

et al. 2020

Int J Applied Ceramic Tech

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Cementitious ceramics, produced from the hydration of cement and hydrated lime, are responsible for a great deal of damage to the environment due to the high emission of CO 2 that occurs in the production of cement and lime. Therefore, the objective of this work was to substitute the hydrated lime with a combination of clay residue and marble waste extracted from ceramic and ornamental rock producing industries, respectively, which constitutes a circular economy for the ceramic industry related to masonry applications. Ceramics were produced in the proportion 1:1:6:1.5 (cement:lime:sand:water), through the molding procedure, and were studied by replacing hydrated lime with 100% clay residue and 100% marble residue, in addition to stoichiometric calculated parts of marble to clay. The molar ratios used were 1:1, 1:2, and 2:1 (marble:clay). Tests of consistency, incorporated air content, water retention, compression strength, density, water absorption by capillarity, adhesion, and electrical resistivity were performed. The results obtained demonstrate that the use of residue of marble and clay together, as long as they are correctly balanced, provides a high gain in technological properties, enabling the circular economy of cementitious ceramics, mainly for the composition 1 marble:1clay, which presented the best properties, both in the fresh and hardened state. The economic analysis carried out proved the financial gains for the industrial sectors involved (civil construction, ornamental rock, and ceramic).

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Section: Methodsmentioning

confidence: 99%

Circular economy in cementitious ceramics: Replacement of hydrated lime with a stoichiometric balanced combination of clay and marble waste

Marvila¹,

Azevedo

Alexandre³

et al. 2020

Int J Applied Ceramic Tech

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“…As is evident, the Langmuir and Freundlich fits were applicable just to the adsorption on both FA and SK+KB. Compared to Pb 2+ , the adsorption capacities (q max and Q t ) reached an order-of-magnitude lower values, which corresponded well to a generally worse adsorption of anions, including AsO 4 3− , on aluminosilicates and other silicate-rich materials [12,[34][35][36]. Indeed, all the source materials belong to this group.…”

Section: Adsorption Of Aso 4 3− On Source Materials and Composite Ads...mentioning

confidence: 83%

Kaolin–Fly Ash Composite for Pb2+ and AsO43− Adsorption from Aqueous System

Doušová,

Bedrnová,

Maxová

et al. 2024

Applied Sciences

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The expected benefit of composite adsorbents generally consists in their growing applicability, thanks to the combination of the adsorption properties of individual components. Composite adsorbents were prepared as mixtures of kaolin from a Czech deposit (kaolin Sedlec, SK) and two fly ashes (FAs) from a fluidised bed boiler in Czech operations differing in fuel type. The mixtures of SK with FA in a ratio of 50:50% wt. were prepared at 20 °C, 65 °C, and 110 °C in an autoclave. The source materials and composite adsorbents were tested for the adsorption of lead as Pb2+, and arsenic as AsO43− from model solutions in laboratory conditions. The adsorption of Pb2+ proceeded quantitatively on the source materials except SK, and on both the composites, with an adsorption yield of >97% and a low adsorbent consumption (~2 g.L−1). The AsO43− adsorption proceeded selectively only on both FAs, with an adsorption yield of >97% again. The adsorption of AsO43− on the composite adsorbents achieved a worse yield (˂80%), with about ten times more adsorbent consumption (~20 g.L−1). An increased preparation temperature did not affect the Pb2+ adsorption at all, but it reduced the efficiency of AsO43− adsorption by up to 30%. The SK–FA composites proved to have promising properties, mostly as cation-active adsorbents.

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“…The main reason for this outcome is that IFGEM-2 contains www.nature.com/scientificreports www.nature.com/scientificreports/ clay, which aggregates the nitrate concentration through electromagnetic force (weak force) 36 on its surface (anion attracted by the positively charged clay surface). Normally the surface of clay is negatively charged, but it can be reversed if the clay particles are modified with metal ions (ferrous and ferric ions in this study) that cover the surface of the clay and form a positively charged layer 37 , enhancing the clay's anion exchange capacity. This further formed a mutual physical attraction between clay particles and iron filings that kept the clay close to the source of metal ions, enhancing the nitrate reduction process through direct contact with iron ( Fig.…”

Section: Discussionmentioning

confidence: 94%

Assessing Nutrient Removal in Stormwater Runoff for Urban Farming with Iron filings-based Green Environmental Media

Wen

Chang

Wanielista

2020

Sci Rep

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Ensuring urban areas have access to clean drinking water, safe food supply, and uncontaminated water bodies is essential to the good health of millions of urban residents. This paper presents the functionality of Iron Filings-based Green Environmental Media (IFGEM) in terms of nutrient removal efficiencies to support water quality management and urban farming. IFGEM uses recycled materials such as tire crumb and iron filings to help remove nutrients with essential physicochemical properties. In this study, IFGEM were proven effective and sustainable through an isotherm study, a column study of reaction kinetics, and a microstructure examination under various inlet nutrient concentration levels. IFGEMs exhibited over 90% nitrate removal, as well as 50-70% total phosphorus removal, under most inlet conditions. These promising results make IFGEM suitable for treating stormwater runoff, wastewater effluent, and agricultural discharge via varying ex situ treatment units in flexible landscape environments. In addition, the byproduct of ammonia generation permits possible reuse of spent IFGEM as soil amendments in crop land, gardens and yards, and green roofs for urban farming. Findings may help secure urban food supply chains and harmonize nutrients, soil, water, and waste management in different urban environments. Globalization and urbanization have reshaped human society, producing a set of complex, interdependent, and interrelated problems in a food-energy-water-waste nexus under the constraint of limited natural resources 1. One of the issues facing sustainable development is the contradiction between nutrient (nitrogen and phosphorus) depletion in agricultural production 2 and nutrient contamination from stormwater runoff, wastewater effluent, and agricultural discharge 3,4. Undesired nutrient loads to natural systems and the built environment create environmental sustainability concerns in terms of ecosystem degradation due to eutrophication and loss of biodiversity 5,6. On the other hand, the rapid growth of the global population constantly increases demands for food production, and modern agriculture largely relies on mining-based fertilizers, which are facing a depletion issue, particularly for phosphorus 7. Through consideration of these intertwined situations, the Environmental Protection Agency 8 promulgated regulatory standards for remediating the impacts from the non-point source pollution 9,10 and resolving the contradictory situation in nutrient management. Best management practices (BMPs) such as filtration basin, grassed swale, green roof, etc., have been used to remediate non-point pollution for decades 11,12. However, existing BMPs are becoming less effective due to increased nutrient concentrations and runoff volumes, as well as soil contamination via rapid urbanization 13,14. One solution is to use green sorption media (i.e., media with the inclusion of recycled materials), designed for enhancing nutrient removal both sustainably and cost effectively. However, there are some design complications ...

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Charge reversal and anion effects during adsorption of metal ions at clay surfaces: Mechanistic aspects and influence factors

Cited by 15 publications

References 57 publications

Circular economy in cementitious ceramics: Replacement of hydrated lime with a stoichiometric balanced combination of clay and marble waste

Circular economy in cementitious ceramics: Replacement of hydrated lime with a stoichiometric balanced combination of clay and marble waste

Kaolin–Fly Ash Composite for Pb2+ and AsO43− Adsorption from Aqueous System

Assessing Nutrient Removal in Stormwater Runoff for Urban Farming with Iron filings-based Green Environmental Media

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