Fixed-Bed Studies on Removal of Arsenic from Simulated Aqueous Solutions Using Chitosan Nanoparticles

Arsenic is a toxic element and may be found in natural as well as in industrial water; therefore, before using water for drinking purpose, its proper treatment is required. Thus, the aim of this work was to evaluate the potential of chitosan nanoparticles, in a continuous-flow method, for the removal of arsenic (III) and (V) from aqueous solutions. All experiments were conducted in fixed-bed columns. Experiments were carried out as a function of varying liquid flow rate (0.3–1.0 ml/min), initial metal concentration (0.5–1.5 mg/L), and bed height (3–9 cm) of adsorbent. The total adsorbed quantity, equilibrium uptake, and total percentage removal of arsenic ions were determined by evaluating the breakthrough curves obtained at different flow rates, initial concentrations, and bed heights. The results showed that the column performed well at the lowest flow rate. Also, column bed capacity and exhaustion time were found to increase with increasing bed height. When initial metal ion concentration was increased from 0.5 to 1.5 mg/L, the corresponding adsorption bed capacity decreased from 0.076 to 0.028 mg/g. The bed depth service time model (BDST) model was used to analyze the experimental data and the model parameters were evaluated. The calculated values of N _o and K _a were found to be 19.28 × 10^?2 mg/L and 0.662 L/mg·min, respectively. Good agreement was found between the experimental breakthrough curves and the model predictions.