The Journal of

 Background: One of the most recent concerns about industrial wastewaters is heavy metals arrival into the water and environment resources. Chromium is found in the trivalent and hexavalent oxidation state by the influence of electroplating and tannery industries. Hexavalent Chromium has proven several health hazards and International Agency for Research on Cancer (IARC) categories. The aim of this study was the evaluation of chromium (VI) removal efficiency by raw Russian knapweed plant Flower Powder from synthetic wastewater.

 Methods: In this study, the effect of initial chromium concentration, adsorbent dose, reaction time and PH on removal of chromium was investigated. The adsorbent prepared in lab conditions and Pulverized by using ASTM standard sieves with a particle size range of 40–60 mesh achieved. The study was performed on synthetic samples containg 2mg/ l and 10 mg/l concentration of chromium. The unknown concentration of Hexavalent Chromium by spectrophotometer set (UV/VisibleSP-3000 Plus-Japan) at 540 nm based on standard methods for testing water and wastewater book was determined.

 Results: According to the results removal, efficiency increases with increasing adsorbent dose and reaction time and decreases with increasing pH solution and initial concentration of chromium. Data of this study showed the maximum adsorption capacity of Hexavalent chromium by raw Russian knapweed Flower Powder for 2mg/ l and 10 mg/l initial concentration 1.66 and 5.72mg/g respectively.

 Conclusion: Raw Russian knapweed Flower Powder is an effective adsorbent for removal of Cr (VI) from aqueous solutions. Although this plant is known as a herbicide but highly porous structure of this plant has caused it to have good adsorption ability. In addition, the adsorbent used the preparation and cost, using this adsorbant is very simple and cheap and has priority in comparison with the other natural and artificial adsorbents.