Removal of Acid Red 14 by Nano-Alumina and Micro-Alumina Powder From Aqueous Solution

Background Many industries can pollute water quality due to their wastewater discharging into water resources. Textile industries are one of the main sources of water pollution. Due to their high toxicity, wastewaters containing dyes cause many environmental problems. Acidic dyes are one of the main classes of dyes. In this study, nano-alumina and micro-alumina powder have been used for the adsorption of acid red 14 dye.
Materials & Methods This study was carried out in the batch system in laboratory scale. Different parameters such as initial dye concentration, pH, and adsorbent dose were examined. Spectrophotometry (UV/VIS Lambda 25 Perkin Elmer, Shelton) was used to quantify the remaining dyes concentration. Adsorption isotherm and kinetic behaviors of adsorbent for acidic dye removal were studied and fitted to different models.
Results The result showed that with increasing the contact time, acid red 14 removal efficiency by micro-alumina and nano-alumina powder and amount of adsorption per mass unit (qe) increased to 18 and 40 mg/L, respectively, and when adsorbent dose increased from 0.2 to 1.2 g/L, qe decreased from 23 to 12 and 47 to 39, respectively. With increasing the pH value in examined range, the removal efficiency decreased from 30 to 6 and 60 to 15 for micro-alumina and nano-alumina powder, respectively. The results of the study of adsorption of acid red 14 by micro-alumina and nano-alumina powder revealed that its kinetics obeyed pseudo-second order (R2>0.99 and 0.98, respectively). The results of present study on adsorption of acid red 14 on micro-alumina and nano-alumina powder revealed that isotherm obeyed Langmuir adsorption (R2 >0.99 and 0.98, respectively).
Conclusion The present study showed that the nano-alumina rather than mciro-alumina can be a promising adsorbent for the removal of acidic dyes such as acid red 14.