Adsorption of Hexavalent Chromium Cr(VI) by Using Local Jordanian Sand (LJS) and Iron Dust-Sand Mixed Adsorbents

Hexavalent chromium is a known carcinogen. It is generated during the electroplating, leather tanning, mining, and photography industries cause harm to the environment and water resources. An attempt for cost effective adsorbent was made by utilizing sand and iron-sand mixed adsorbents. Sand adsorbent was found to exhibit remarkable adsorption capacity for hexavalent chromium. The extent of Cr(VI) removal was found to be dependable on the solution pH, Cr(VI) initial concentration, contact time, sand adsorbent dosage, and the iron content in iron-sand mixed adsorbent. The optimum pH for the removal was found to be 2. The highly removed concentrations by sand adsorbent ranged from 0 to 40 mg/l. It was found that as contact time increases the removal efficiency of Cr(VI) increases. Variation in sand adsorbent dosages indicated that as the adsorbent dosage increases the removal efficiency increases and it was reached to 65% at 40 hours. On the other hand, the effect of iron mixed with sand adsorbent was examined at two stages; first, at low Cr (VI) concentration solution of 20 mg/l, and, second, at high initial concentration of Cr(VI) up to 1000 mg/l. By using the optimal iron dosage, the removal efficiencies were increased to 99% within 1 to 3 hours at 20, 61, 171, 345 and 1000 mg/l of Cr(VI) initial concentrations.