Microwave induced beta-cyclodextrin modification of chitosan for lead sorption.
Microwave induced copolymerization of beta-cyclodextrin (beta-CD) and chitosan (Ch) resulted in copolymer Ch-g-beta-CD synthesized without any radical initiator or catalyst. Copolymer samples of different performances in terms of Pb(II) binding were synthesized by changing beta-CD concentration at fixed microwave power and exposure time. To understand the advantage of using microwaves in the adsorbent synthesis, the copolymer synthesized using a K(2)S(2)O(8)/ascorbic acid redox pair at identical beta-CD and Chitosan concentrations (% G 103) was also evaluated as Pb(II) sorbent, and the results obtained were compared with that of microwave synthesized copolymer. A representative sample of microwave synthesized adsorbent was characterized using FTIR spectroscopy, X-ray diffraction, TGA, SEM analysis and using this sample adsorption of lead (II) was studied as a function of pH, initial Pb(II) concentration. The adsorption data followed both Freundlich and Langmuir isotherms. On the basis of the Langmuir model, Q(max) was calculated to be 434.78mg/g for microwave synthesized copolymer (Ch-g-beta-CD) in comparison to 294.11mg/g for conventionally synthesized copolymer (Ch-g-beta-CD). In order to investigate dynamic behaviour of Ch-g-beta-CD as an adsorbent, the kinetic data were modelled using pseudo-second-order and second-order. The regeneration experiments revealed that the Ch-g-beta-CD can be successfully reused for seven cycles.
Sharma
A K
AK
UJ Nanomaterials Science Research Group, Department of Chemical Technology, University of Johannesburg, Doornfontien 2028, Johannesburg, South Africa.
Mishra
A K
AK
D000327:Adsorption; D048271:Chitosan / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry; D005240:Feasibility Studies; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007854:Lead / Q000737:chemistry* / Q000302:isolation & purification*; D008872:Microwaves; D013057:Spectrum Analysis; D047392:beta-Cyclodextrins / Q000737:chemistry*
D004573:Electrolytes; D047392:beta-Cyclodextrins; D007854:Lead; D048271:Chitosan