Application of Eggshell as a Natural Sorbent for the Removal of Reactive Red 123 Dye from Synthetic Textile Wastewater

Background: Dye is one of the most important pollutants in textile industrial wastewater. The scope of this study was to evaluate the feasibility application of eggshell as a sorbent for the removal of reactive red 123 dyes from synthetic wastewater.

  Materials and Methods: This study is an applied- experimental research which was performed in laboratory scale and in environmental chemistry laboratory of Baqiyatallah (a.s) university of medical sciences. Eggshell as a sorbent was prepared in laboratory condition (20-25^°C) and pulverized by standard ASTM sieves. The effective size (D₁₀) and D₆₀ were 3 and 5.1mm, respectively and uniformity coefficient (UC) was 1.7. The concentrations of dye in wastewater were 25 and 50 mg/l.

  Results: In this study increasing of adsorbent dose from 1 to 5 g/100ml led to increase of the adsorption efficiency from 48 to 80.7 %. The maximum adsorption took place in first 60min of reaction. With increasing the temperature up to 45^°C the pollutant adsorption was increased and increasing of pH from 5 to 8 led to increase of process efficiency from 30 to 48%. Also absorption characteristics of this pollutant on eggshell accommodated with Langmuir isotherm.

  Conclusion: Eggshell can be used as a natural adsorbent in water and wastewater treatment. This adsorbent is an appropriate media for the treatment of textile wastewater that usually have alkaline condition and high temperature.