Removal of chromium(VI) from aqueous solution using treated waste newspaper as a low-cost adsorbent: Kinetic modeling and isotherm studies

In the present study, treated waste newspaper (TWNP) was used to remove chromium(VI) from aqueous solution using batch experiments. The adsorption parameters optimized were: initial Cr(VI) concentration (5, 20, 50 mg/l), contact time (60 min.), adsorbent dose (3.0 g/L), and solution pH (3.0). The experimental data fitted well to Langmuir isotherm (R2 = 0. 98; maximum adsorption capacity 59.88 mg/g.) and pseudo-second-order kinetic model. The rate constant k2 varied from 0.0019 to 0.0068 at initial Cr (VI) concentration from 5 to 20 mg/L. It was observed that adsorption of Cr(VI) was pH dependent. The percentage removal of Cr(VI) was 59.88 mg/g (64% at pH 3). The results of the present study suggest that TWNP may be used as a low-cost adsorbent for the removal of chromium (VI) from aqueous solutions.