Functionalised pseudo-boehmite nanoparticles as an excellent adsorbent material for anionic dyes

Auxilio, Anthony R., Andrews, Philip C., Junk, Peter C., Spiccia, Leone, Neumann, Daniel, Raverty, Warwick, Vanderhoek, Nafty, and Pringle, Jennifer M. (2008) Functionalised pseudo-boehmite nanoparticles as an excellent adsorbent material for anionic dyes. Journal of Materials Chemistry C, 18 (21). pp. 2466-2474.

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View at Publisher Website: http://dx.doi.org/10.1039/b715545j
 
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Abstract

Pseudo-boehmite has been functionalised with L-lysine by refluxing an aqueous solution containing these two reactants overnight. The resulting nanosized (<10 nm) product is insoluble in water and has been characterised by solid-state NMR spectroscopy, powder X-ray diffraction analysis, N2 adsorption–desorption analysis and zeta potential measurements. The affinity of this new nanostructured organic–inorganic hybrid material for anionic dyes has been quantified using UV-vis spectrophotometry and by constructing the adsorption isotherms for Acid Blue 9 (AB9), Acid Yellow 23 (AY23), and Acid Red 37 (AR37). Elemental/micro analyses indicate that one lysine molecule is covalently bonded to every 8 nm2 of the functionalised material giving a composition [(AlOOH)230·(H2O)86·(C6N2O2H15)]. The introduction of the positively charged amino groups resulted in a tremendous increase in dye affinity in contrast to the unfunctionalised material. The adsorption isotherms of the functionalised pseudo-boehmite were fitted to the Langmuir model and yielded equilibrium binding constants (Ka) of 2.6 × 103 M−1 for AB9, 1.5 × 105 M−1 for AY23 and 8.4 × 104 M−1 for AR37. AR37 gave a higher monolayer coverage (Cm) value of 0.13 mmol g−1 than AB9 (0.085 mmol g−1) and AY23 (0.081 mmol g−1). Dye adsorption is correlated with surface coverage of L-lysine and, in the case of AR37, two dye molecules are concluded to be adsorbed per L-lysine while for AY23 a multi-point interaction is proposed to result in a lower dye capacity and a relatively higher affinity of this dye for FPB when compared with AR37.

Item ID: 29631
Item Type: Article (Research - C1)
ISSN: 2050-7534
Keywords: inorganic-organic hybrid; aluminum-hydroxide; crystallite size; adsorption; surface; alumoxanes; particles; pepsin; layers; water
Funders: Smartprint Cooperative Research Centre (CRC), Australia
Date Deposited: 02 Oct 2013 10:34
FoR Codes: 03 CHEMICAL SCIENCES > 0302 Inorganic Chemistry > 030299 Inorganic Chemistry not elsewhere classified @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970103 Expanding Knowledge in the Chemical Sciences @ 100%
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