The application of Azolla filiculoides biomass in acid blue 15 dye (AB15) removal from aqueous solutions

Introduction: Industrial wastewater is one of the most important environmental pollutants. Discharging the colorful industrial effluents into receiving waters can lead to eutrification which has many adverse effects on human health. Therefore, the present study aimed at evaluatingacid blue 15 dye removal from aqueous solution by dried Azolla. Materials and methods: Azolla biomass was dried in the sunlight, and then crushed and sieved to particle sizes in range of 1-2 mm. Next, it was treated with 0.1 M HCl for a period of 5 hours. The Azolla was washed with distilled water and used as absorbent. The effect of operating parameters such as pH, contact time, AB 15 concentration and adsorbent dose on the AB15 removal efficiency was investigated. The dye concentration was measured by spectrophotometer (DR4000) at λmax =565nm. Results: In optimum condition (pH 3, contact time 90 min , absorbent dose 10 g/l and AB15 concentration 10 ppm), application of Azolla removed 98% of AB15 from aqueous solutions. The equilibrium data was best fitted on Langmuir isotherm and the adsorption kinetic model followed a pseudo-second model. Conclusion: The obtained results showed that the dried Azolla can be used as a high efficiency and low-cost absorbent to treat textile effluents.