Impact of Cross-linking Agents on the Performance of Alginate- Cellulose Nanocrystals Adsorbent Beads

A detailed investigation on the adsorption of methylene blue (MB) to sodium alginate/cellulose nanocrystal (ALG-CNC) composite hydrogel beads was conducted. The impact of physical cross-linking and calcium ions on the binding of MB onto the beads and the swelling/shrinkage of bead during the adsorption process in batch vessel and continuous fixed bed operations was examined. Changes in the bulk calcium ion concentrations during the batch adsorption experiments on the binding of MB to the beads were monitored when the beads were subjected to different pretreatments. The calcium ions reduced the adsorption capacity by charge screening instead of competitive adsorption, and the removal of calcium ions contributed to an initial shrinkage of the adsorbent during binding tests in the packed column.