Removal of hexavalent chromium (VI) from aqueous solutions using surface modified nanozeolite A

Chromium (VI) adsorption behavior and capacity by surface modified nanozeolite A has been investigated. Surface modification was performed and the morphology of modified and unmodified nanozeolite was studied using Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). Adsorption isotherms were studied under different conditions (pH, adsorbent dose, adsorbate concentration and interaction time). The Langmuir monolayer adsorption capacity (q_m ) was found to be 14.16 mg Cr(VI) per gram at pH = 3.0 at room temperature. Chromate adsorption on surface modified nanozeolite A was found to be inversely proportional to the pH. Effect of competitive ions was studied and it was found that there is no significant competition between chromate adsorption and presence of competitive ions. Results revealed that Langmuir model is in good agreement with experimental re-sults. Results of examinations on a polluted natural sample showed that surface modified nanozeolite A could reduce chromium (VI) concentration to acceptable criteria. Based on results, surface modified nanozeolite A is an effective sorbent for removing chromate from aquatic solution and the adsorption ability is enhanced by surface modification.