Adsorption of methyl violet from aqueous solution by halloysite nanotubes

Liu, Ruichao; Zhang, Bing; Mei, Dandan; Zhang, Haoqin; Liu, Jindun

doi:10.1016/j.desal.2010.10.006

Cited by 237 publications

(94 citation statements)

References 40 publications

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“…19,20 In this study, the correlation coefficient of the pseudo-second-order model is higher than that of the pseudofirst-order model, and the calculated adsorption capacities obtained from the pseudo-second-order model agree well with the experimental data, which suggests that the pseudo-secondorder kinetic model is more suitable for describing the dye adsorption process. According to a theoretical approach, when the initial concentration is lower than a critical concentration, then the pseudo-second-order model is suitable for the analysis of adsorption kinetics, and when the initial concentration is higher than the critical concentration, then the pseudo-first-order model is suitable for describing the adsorption kinetics.…”

Section: ¹1supporting

confidence: 69%

“…The results revealed that a higher initial concentration is favorable for dye adsorption, indicating that the higher concentration gradient between dye in solution and dye on the adsorbent surface is a driving force for dye adsorption. 19,20 Meanwhile, the dye adsorption capacity increases with increasing temperature at the same initial concentration, suggesting that the adsorption process is endothermic.…”

Section: ¹1mentioning

confidence: 99%

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Halloysite Nanotube/Polyelectrolyte Hybrids as Adsorbents for the Quick Removal of Dyes from Aqueous Solution

Tao

Higaki

Ma³

et al. 2015

Chem. Lett.

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Novel organic/inorganic hybrids composed of halloysite nanotubes (HNTs) and a cationic polymer were prepared through a simple mixing method. The hybrids provide more gaps for water permeation than the pristine HNTs when used as column adsorbents, and quick dye removal from polluted water was achieved.Dyes are widely used in industrial products including paper, textile, printing, plastic, etc. However, because of their complex substituted aromatic groups, most dyes show great resistance to the decomposition by chemical, physical, and biological treatments. Furthermore, their degradation may generate other undesirable toxic and carcinogenic products. 13 Adsorption has been applied as an efficient and economical approach for dye removal from wastewater.4,5 Many low-cost naturally occurring mesoporous adsorbents have been widely investigated for water purification, such as zeolites, kaolinite, and montmorillonite. However, none of them show high adsorption capacity for both positive and negative dyes. 611 Recently, halloysite nanotube (HNT) nanoclay materials have attracted great interest in academia and industry due to their hollow tubular structure, high surface area, and the asymmetric chemical structures of the inner and outer surfaces. HNTs have wrapped layer morphologies with negatively charged SiOH on the external surface and positively charged AlOH on the inner surface, which enable the HNTs to adsorb both positive and negative pollutants. 1215Although HNTs show significant adsorption capacity for various dyes, they cannot be directly used for dye removal from aqueous solution, because HNTs form a stable colloidal suspension in water, making their separation from water very difficult. Besides, compacted HNTs do not supply enough pathways for water permeation during column filtration. Recently, HNT/polymer (alginate, chitosan) hybrid beads have been applied to solve these problems for dye removal applications. However, the preparation procedures are complicated and post-treatment is necessary. 16,17 In order to overcome the drawbacks of HNTs mentioned above, we designed a novel HNT/polyelectrolyte hybrid adsorbent, which is prepared by simple mixing of pristine HNTs and a cationic synthetic copolymer of poly(acrylamide-codiallyldimethylammonium chloride) [P(AAm-co-DADMAC)]. The effects of adsorbent dose, temperature, initial concentration, and contact time on the adsorption of cationic dye Basic Blue 7 (BB7) from aqueous solution were investigated. The equilibrium isotherms, kinetics data, and thermodynamic parameters were calculated to understand the adsorption mechanism of BB7 onto the hybrids.HNTs were purchased from Sigma-Aldrich and dried at 150°C for 3 days under vacuum before use. HNTs have diameters of 3070 nm with lengths of 200 nm to 2¯m. P(AAm-co-DADMAC) (acrylamide composition: 55 wt %) 10 wt % aqueous solution was purchased from Sigma-Aldrich and used as received (Figure 1a). 3 g of HNTs were dispersed in deionized water (20 mL) by sonication for 15 min. Subsequently, 7.9 mg mL ¹1 P(AAm-co-DADMA...

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Section: ¹1supporting

confidence: 69%

Section: ¹1mentioning

confidence: 99%

Halloysite Nanotube/Polyelectrolyte Hybrids as Adsorbents for the Quick Removal of Dyes from Aqueous Solution

Tao

Higaki

Ma³

et al. 2015

Chem. Lett.

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“…2). Such a behavior was observed practically by all the groups using halloysite as an adsorber for compounds [17,18,[39][40][41][42].…”

Section: Halloysite Characteristicsmentioning

confidence: 91%

“…Solution concentrations ranged between 0.03 and 0.3 g/dm 3 with the most frequent value of 0.05 g/dm 3 or less [17,18,39,42], while halloysite content changed between 1 and 8 g/dm 3 with the usual value of 1 g/dm 3 [17,18,39,42]. In our experiments the corresponding concentrations of the solutions were 0.03-2.00 g/dm 3 and uniformly 10 g/dm 3 for the suspension.…”

Section: Halloysite Characteristicsmentioning

confidence: 95%

Adsorption of an active molecule on the surface of halloysite for controlled release application: Interaction, orientation, consequences

Hári

Polyák

Mester

et al. 2016

Applied Clay Science

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The goal of the study was to check the possible use of halloysite nanotubes as a controlled release natural antioxidant device with quercetin as the active component. The mineral was thoroughly characterized by various techniques including the determination of particle and tube morphology, specific surface area, pore size and volume, as well as surface energy. The high surface energy of halloysite predicted strong adsorption of active molecules on its surface and consequently difficult release. FTIR spectroscopy confirmed the existence of strong interactions, energetically heterogeneous halloysite surface and multilayer coverage at large loadings. FTIR and XRD experiments proved the complete lack of intercalation and showed that below 3.5 wt% quercetin loading, most of the molecules are located within the halloysite tubes. Molecular modelling indicated the parallel orientation of quercetin molecules with the surface. Critical concentrations derived from various measurements agreed well with each other further confirming that up to about 4.0 wt% loading, quercetin is bonded very strongly to the halloysite surface. As a consequence, the dissolution of active molecules is very difficult or impossible, especially into apolar media, thus neither stabilization nor controlled release effect can be expected below that concentration.

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“…It has been used as support for immobilization of catalysts such as metallocomplexes (Nakagaki & Wypych, 2007;Machado et al, 2008) and for the controlled release of anti-corrosion agents, herbicides, fungicides Shchukin et al, 2006;Shchukin & Mohwald, 2007). It exhibits interesting features and offers potential application as entrapment of hydrophilic and lipophilic active agents, as enzymatic nanoscale reactor (Shchukin et al, 2005); as sustained release of drugs (Price et al, 2001;Levis & Deasy, 2003;Kelly et al, 2004;Veerabadran et al, 2007); as adsorbing agent for dye removal (Liu et al, 2011). It can be employed to improve mechanical performance of cements and polymers (Hedicke-Höchstötter et al, 2009).…”

Section: Wwwintechopencommentioning

confidence: 99%