Improvement of metal adsorption onto chitosan/Sargassum sp. composite sorbent by an innovative ion-imprint technology

Abstract

Ion-imprinted chitosan Sargassum sp. a b s t r a c tTechnology for immobilization of biomass has attracted a great interest due to the high sorption capacity of biomass for sequestration of toxic metals from industrial effluents.However, the currently practiced immobilization methods normally reduce the metal sorption capacities. In this study, an innovative ion-imprint technology was developed to overcome the drawback. Copper ion was first imprinted onto the functional groups of chitosan that formed a pellet-typed sorbent through the granulation with Sargassum sp.; the imprinted copper ion was chemically detached from the sorbent, leading to the formation of a novel copper ion-imprinted chitosan/Sargassum sp. (CICS) composite adsorbent. The copper sorption on CICS was found to be highly pH-dependent and the maximum uptake capacity was achieved at pH 4.7e5.5. The adsorption isotherm study showed the maximum sorption capacity of CICS of 1.08 mmol/g, much higher than the non-imprinted chitosan/Sargassum sp. sorbent (NICS) (0.49 mmol/g). The used sorbent was reusable after being regenerated through desorption. The FTIR and XPS studies revealed that the greater sorption of heavy metal was attributed to the large number of primary amine groups available on the surfaces of the ion-imprinted chitosan and the abundant carboxyl groups on Sargassum sp.. Finally, an intraparticle surface diffusion controlled model well described the sorption history of the sorbents. ª 2010 Elsevier Ltd. All rights reserved. IntroductionBiosorption has been considered as a promising technology for the removal of low-level toxic metals from industrial effluents and natural waters (Volesky, 2007;Mehta and Gaur, 2005;Wang and Chen, 2009). Marine algae have received greater attention because of their high metal biosorption capacity, low cost, and renewable nature. They can effectively remove heavy metal ions with concentrations ranging from few ppm to several hundreds ppm. The maximum metal biosorption capacity ranging from 0.1 to 1.5 mmol/g biosorbent has been reported (Davis et al., 2003; Yang, 2005, 2006 A v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / w a t r e s w a t e r r e s e a r c h 4 5 ( 2 0 1 1 ) 1 4 5 e1 5 40043-1354/$ e see front matter ª

Biosorption of Cd2+ by untreated dried powder of duckweed Lemna aequinoctialis

“…The results presented here are useful for the practical application of L. aequinoctialis as a biosorbent to remove of Cd 2+ from the wastewater in future. Moreover, previous research had shown that the maximum sorption capacity of immobilized biomass was much higher than that of non-immobilized biomass [34]. Studies concerning immobilized L. aequinoctialis and its effect on heavy metal ion adsorption will be carried out in the future.…”

Correlation of Ionic Imprinting Cavity Sites on the Amino-Silica Hybrid Adsorbent with Adsorption Rate and Capacity of Cd2+ Ion in Solution

“…Fig. 7 e f e C n K q log 1 log log + = ... (16) ... (17) ... (18) ... (19) where, q m is the maximum metal ion amount adsorbed (mg g In Table 3, it can be seen that increasing of adsorption capacity occurred on Cd(II)-IIP higher than NIP. Surface of Cd(II)-IIP material was to be more selective and specific upon metal ion used as a template.…”

“…Several researches were performed to increase a number of active sites through adsorbent modification with adding specific functional groups 11,12 . In addition, it was performed increasing of the adsorbent active site selectivity to target metal ion via an ionic imprinting technique [13][14][15][16][17][18] .…”

Removal of cobalt(II) ion from aqueous solution by chitosan–montmorillonite

“…Langmuir, Freundlich and Temkin isotherms are widely used to describe the adsorption characteristics of adsorbents. Important information about adsorbent surface properties can be known from the adsorption isotherms (Liu et al, 2011;Juang and Shao, 2002), and the linear form of Langmuir, Freundlich and Temkin isotherms can be written as Eqs. (1)- (3), respectively.…”