Application of Bone Char as a Natural Biosorbent for the Removal of Acid Orange 7 dye from Synthetic Textile Wastewater

The textile industry produces a colored effluent with different characteristics that needs to be treated. Adsorption is one of the methods for removing dyes. The aim of this study was to evaluate application of bone char as natural adsorbent for removal of acid orange 7 from synthetic textile wastewater. In this study, the effect of variations such as contact time, pH, initial dye concentration, adsorbent dose and agitation rate on efficiency of dye removal was investigated. At first, the solution of acid orange 7 was prepared. Dye removal efficiency was measured by UV/visible spectrophotometer and at 484 nanometer. According to the results, pH can enjoy an important role in contaminant removal by this adsorbent so that by decreasing pH, dye adsorption rate increases. The maximum of dye adsorption capacity on bone char has taken place 0.74 mg/g at pH:3. The results showed that by decreasing initial dye concentration and by increasing adsorption rate, the amount of adsorbed pollutant at adsorbent mass unit decreased. By increasing adsorbent dose from 0.5 to 4 g/100 ml, dye removal efficiency increased. By decreasing initial dye concentration from 100 to 25 mg/l at pH:3 at 180 min, removal efficiency increased from 10% to 96%. At 25 and 50 mg/l concentration, by increasing agitation rate from 40 to 120 rpm, capacity of dye adsorption at adsorbent mass unit also increased. The appropriate time to get the maximum of dye adsorption and equilibrium state was 180 min. Due to easy preparation, ample initial matter and significant function of bone char as a natural adsorbent for removal of pollutants from textile wastewater, this adsorbent is effective for dye removal.