Synergistic adsorption of heavy metal ions and organic pollutants by supramolecular polysaccharide composite materials from cellulose, chitosan and crown ether

Abstract

We have developed a simple one-step method to synthesize novel supramolecular polysaccharide composites from cellulose (CEL), chitosan (CS) and benzo-15-crown 5 (B15C5). Butylmethylimidazolium chloride [BMIm+Cl−], an ionic liquid (IL), was used as a sole solvent for dissolution and preparation of the composites. Since majority of [BMIm+Cl−] used was recovered for reuse, the method is recyclable. The [CEL/CS + B15C5] composites obtained retain properties of their components, namely superior mechanical strength (from CEL), excellent adsorption capability for heavy metal ions and organic pollutants (from B15C5 and CS). More importantly, the [CEL/CS + B15C5] composites exhibit truly supramolecular properties. By itself CS, CEL and B15C5 can effectively adsorb Cd2+, Zn2+ and 2,4,5-trichlorophenol. However, adsorption capability of the composite was substantially and synergistically enhanced by adding B15C5 to either CEL and/or CS. That is, the adsorption capacity (qe values) for Cd2+ and Zn2+ by [CS + B15C5], [CEL + B15C5] and [CEL + CS + B15C5] composites are much higher than combined qe values of individual CS, CEL and B15C5 composites. It seems that B15C5 synergistically interact with CS (or CEL) to form more stable complexes with Cd2+ (or Zn2+), and as a consequence, the [CS + B15C5] (or the [CEL + B15C5]) composite can adsorb relatively larger amount Cd2+ (or Zn2+). Moreover, the pollutants adsorbed on the composites can be quantitatively desorbed to enable the [CS + CEL + B15C5] composites to be reused with similar adsorption efficiency.

Nanocelluloses and their phosphorylated derivatives for selective adsorption of Ag+, Cu2+ and Fe3+ from industrial effluents

“…Biosorption, which has already gained much attention, can be used to reduce the concentration of heavy metal ions in solution from ppm to ppb level [1,8,9]. However, conventional adsorbents are usually limited by the lack of selectivity and lower adsorption kinetics due to the limited surface area or active sites [10].…”

Advances in the Development of Supramolecular Polymeric Biomaterials

“…The superior adsorption properties of the material are attributed to the presence of the crown ether. 30 In order to develop proteinresistant materials, Guan et al studied the structure-property relationship of a carbohydrate-derived side-chain ether polymer. It was shown by surface plasmon resonance that side-chain permethoxylated polyesters demonstrate excellent protein resistance toward nonspecific protein adsorption.…”

Preparation and characterization of bijoypur clay-crystalline cellulose composite for application as an adsorbent

“…Cellulose is a polysaccharide containing about 1500 β-glucose units where the chains are connected together with hydrogen bonds [18]. Importantly, cellulose contains hydroxyl (-OH) groups on the glucose ring acting as coordination sites to heavy metal ions making it an attractive natural adsorbent [19][20][21].…”