Cr(VI) adsorption on the blends of Henna with chitosan microparticles: Experimental and statistical analysis

In this work, the capability of blends of Henna with chitosan microparticles as novel adsorbent was studied in order to remove Cr(VI) ions. Response surface method (RSM) as a statistical technique was used to minimize number of experiments (26 runs), and optimize the operating conditions. In order to study Cr(VI) adsorption on the adsorbent, the effects of process parameters namely pH (2-9), initial Cr(VI) solution concentration (10-100 mg/L), Henna dose (0.1-1 g/L), chitosan microparticles dose (0.1-1 g/L) and contact time (20-150 min) were carefully considered. The adsorption did not change from pH 2 to 9 while it was reduced from 100% to 98.67% by growing Cr(VI) initial concentration. In addition, the adsorption was increased from 98.04% to 100% by increasing the adsorbent amount. The result of the isotherm study fitted well to Langmuir model (with R2 = 0.9826).