Fixed-bed column studies for the removal of cationic and anionic dyes by chemically modified oil palm empty fruit bunch fibers: single- and multi-solute systems

The adsorption performance of cationically and anionically modified oil palm empty fruit bunch fibers toward methylene blue (MB) and phenol red (PR) was investigated using single- and multi-solute systems in a fixed-bed system. The experimental data were fit with Thomas and Clark column adsorption models to evaluate different experimental conditions (adsorbate dose, bed height, column temperature, and flow rate). The results suggest that the adsorption mechanism was that of monolayer and heterogeneous. The service time of each bed was estimated using a bed depth service time model by considering the adsorption rate. The regeneration of the adsorbent for up to five adsorption/desorption cycles was investigated, suggesting the excellent reusability of the adsorbent column. The simultaneous removal of mixed MB and PR was achieved using both fibers packed with different configurations.