Halloysite/alginate nanocomposite beads: Kinetics, equilibrium and mechanism for lead adsorption

Chiew, Christine Shu Ching; Yeoh, Hak Koon; Pasbakhsh, Pooria; Krishnaiah, K.; Poh, Phaik Eong; Tey, Beng Ti; Chan, Eng Seng

doi:10.1016/j.clay.2015.10.032

Cited by 98 publications

(21 citation statements)

References 26 publications

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“…To the best of our knowledge, no reports of CaAlg degradation due to alkalinity have been made to date. However, there is evidence of cation exchange in the Ca–M block of alginate under salt attack [ 61 ] or in the presence of other cations [ 62 ], which may explain the morphological observations. CF is highly alkaline and ionic and can result in salt attacks on the CaAlg structure.…”

Section: Resultsmentioning

confidence: 99%

Biological Self-Healing of Cement Paste and Mortar by Non-Ureolytic Bacteria Encapsulated in Alginate Hydrogel Capsules

et al. 2020

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Crack formation in concrete is one of the main reasons for concrete degradation. Calcium alginate capsules containing biological self-healing agents for cementitious materials were studied for the self-healing of cement paste and mortars through in vitro characterizations such as healing agent survivability and retention, material stability, and biomineralization, followed by in situ self-healing observation in pre-cracked cement paste and mortar specimens. Our results showed that bacterial spores fully survived the encapsulation process and would not leach out during cement mixing. Encapsulated bacteria precipitated CaCO3 when exposed to water, oxygen, and calcium under alkaline conditions by releasing CO32− ions into the cement environment. Capsule rupture is not required for the initiation of the healing process, but exposure to the right conditions are. After 56 days of wet–dry cycles, the capsules resulted in flexural strength regain as high as 39.6% for the cement mortar and 32.5% for the cement paste specimens. Full crack closure was observed at 28 days for cement mortars with the healing agents. The self-healing system acted as a biological CO32− pump that can keep the bio-agents retained, protected, and active for up to 56 days of wet-dry incubation. This promising self-healing strategy requires further research and optimization.

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Section: Resultsmentioning

confidence: 99%

Biological Self-Healing of Cement Paste and Mortar by Non-Ureolytic Bacteria Encapsulated in Alginate Hydrogel Capsules

et al. 2020

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“…Using HNTs can enhance the mechanical performance of biopolymer beads like alginate due to a greater elastic modulus of the HNTs. The HNT/alginate nanocomposite beads have been used by Chiew et al (2016) as these adsorbents incorporate the distinctive merits of both HNTs and alginate, which include a high affinity towards Pb 2+ , strong mechanical properties and easy separation from the treated solution (Chiew et al, 2016). The beads have been designed to remove Pb 2+ from aqueous solutions by adsorption (Fig.…”

Section: Hnt/alginate Beads For Lead Adsorptionmentioning

confidence: 99%

Halloysite nanotubes: prospects and challenges of their use as additives and carriers – A focused review

et al. 2016

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There is increasing research interest in potential applications of halloysite as fillers for polymer composites, controlled drug delivery, carriers for the supply and sustained release of active agents for anticorrosion coatings, in nanoreactors or nanotemplates, and for the uptake of contaminants or pollutants and support for catalysts. In this review, recent findings in terms of the prospects and challenges of using halloysite nanotubes (HNTs) in different polymeric matrices targeting a range of old and new applications are discussed and evaluated. The compositions include chitosan/halloysite membranes as bone-tissue scaffolds, polylactic acid (PLA)/halloysite membranes for food-packaging applications and their antimicrobial activities, instrumented impact properties of epoxy/halloysite nanocomposites and the role of halloysite in the self-healing of epoxy composites, polyacryronitrile (PAN)/halloysite membranes for use in water filtration as well as a review of some recent applications of halloysite/alginate beads in the adsorption of contaminants such as lead.

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“…Despite the multiple advantages related to their small size and large surface area, which ideally increases the adsorption efficiency, it is difficult to eliminate these nanoparticles from treated solution due to their fine size (Zhao et al., ). An effective method to overcome these complications is by immobilizing chitosan nanoparticles with alginate, because of simple preparation and high adsorption potential for removing of heavy metals (Chiew et al., ).…”

Section: Introductionmentioning

confidence: 99%

Uptake of Pb(II) onto nanochitosan/sodium alginate hybrid beads: Mechanism and kinetics study

Ablouh

Essaghraoui

Eladlani

et al. 2019

Water Environment Research

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Nanochitosan/sodium alginate (NCS/SA) beads were prepared using nanochitosan and alginate as a high-performance absorbent for Pb(II) removal from aqueous solution. The morphology, structure, thermal stability, surface area, and elements present in the NCS/SA beads before and after adsorption were characterized using instrumental techniques like SEM, FTIR, TGA, BET, and EDX analysis, respectively. Various adsorption parameters were studied. The results indicated that the equilibrium adsorption data were fitted to Langmuir isotherms and the maximum Langmuir monolayer capacity of Pb(II) was 178.57 mg/g at 45°C. The adsorption process was in good agreement with pseudo-first-order kinetic model. Mechanism studies showed that electrostatic interaction and ion exchange were the major mechanisms for lead (II) removal by the NCS/SA beads. The results of this study indicate that NCS/SA beads could be used as an effective adsorbent for the elimination of lead (II) present in aqueous solution. • Practitioner points• Nanochitosan/sodium alginate beads were synthesized using Ca 2+ as a crosslinking agent. • NCS/SA beads were used to remove Pb(II) for the first time and working parameters were optimized. • Adsorption monolayer capacity of NCS/SA adsorbent towards Pb (II) was found to be 178.57 mg/g.

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Halloysite/alginate nanocomposite beads: Kinetics, equilibrium and mechanism for lead adsorption

Cited by 98 publications

References 26 publications

Biological Self-Healing of Cement Paste and Mortar by Non-Ureolytic Bacteria Encapsulated in Alginate Hydrogel Capsules

Biological Self-Healing of Cement Paste and Mortar by Non-Ureolytic Bacteria Encapsulated in Alginate Hydrogel Capsules

Halloysite nanotubes: prospects and challenges of their use as additives and carriers – A focused review

Uptake of Pb(II) onto nanochitosan/sodium alginate hybrid beads: Mechanism and kinetics study

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