Synthesis and use of esterified sawdusts bearing carboxyl group for removal of cadmium(II) from water

Preparation and Characterization of Wheat Straw Hemicellulosic Succinates

“…Therefore, a pre-swelling step and a suitable solvent or catalyst should be added to the reaction system to increase the accessibility of the reactive hydroxyl groups of the hemicelluloses to the reactions. Similar observations were found in the reaction of wood with succinic anhydride by Marchetti et al [16] . Furthermore, to obtain esterified hemicelluloses bearing carboxyl groups, the anhydride should be used in the liquid state by dissolving in DMF solvent since succinic anhydride has a mp of 119-120 C. In this study, the succinylated hemicelluloses containing free carboxylic groups were prepared by reaction of the polysaccharide with succinic anhydride to yield the mono-esterified dicarboxylic acid using pyridine as catalyst and DMF=LiCl system as solvent, since DMF=LiCl is suitable for this mono-esterification and the reaction in DMF=LiCl system proceeds smoothly at 80 C. Nonpolar solvent like hexane leads to poor grafting efficiency, whereas polar solvent like DMF gives satisfactory result, although DMF is a expensive solvent for esterification reactions.…”

Preparation of carboxylate-functionalized cellulose via solvent-free mechanochemistry and its characterization as a biosorbent for removal of Pb2+ from aqueous solution

“…Recent research on carboxylate-functionalized cellulose has revealed that these materials exhibit a specific binding ability towards highly toxic heavy metals as a consequence of a soft Lewis acid-soft Lewis base interaction (Pearsons' theory). Their chemical stability in acidic media as well as the possibility of regeneration by washing with concentrated HCl allows the reuse of these adsorbent materials for several cycles [1][2][3][4][5][6][7]. However, the current synthetic routes for such biosorbents always involve organic solvents like pyridine, N,N-dimethyl formamide (DMF), which are also harmful to the human body.…”

Chemical Modifications of Douglas Fir Bark, a Lignocellulosic By‐product—Enhancement of Their Lead(II) Binding Capacities

“…The adsorption process also depends upon the adsorbent surface chemistry. [17] Both acidic-formaldehyde treatment and esterification increase forest by-product binding capacities; however, the use of toxic solvents/reagents is the major drawback of theses methods. [4,5,13] The aim of this study is to enhance the metal sorption capacities of barks (quantitative and qualitative aspects) by introduction of covalently bound weak/or strong acidic functional groups, ORDER REPRINTS such as carboxyl or sulfonyl.…”