The study of absorption kinetics of congo red dye on peanut sticks waste in batch system

Dyes are industrial materials which make lots of problem for environment. Congo red is an azo dye that contains azo functional groups. Some common wastewatertreatment methods are ineffective because dyes usually are non-biodegradable. In this work, design of experimental (DOE) method using Taguchi orthogonal array (OA) is performed to assess the influence of five factors (i.e., initial concentration of dye, contact time, pH, temperature, particle size and dosage of adsorbent,) on the removal efficiency of Congo red dye from wastewater. The results indicated that by increasing contact time the removal efficiency of Congo red increases rapidly and then slowly reaches to equilibrium time (110 min). Also, by increasing adsorbent from 1 to 4 gr/l the yield of removal dye increases. The optimal initial concentration adsorbent is estimated the lowest one (50 ppm). Maximum dye removal efficiency is obtained in pH=6 that it is 99.26 % and the adsorbent capacity is achieved 12.41 mg/g. The results showed that the process was exothermic so the adsorption was more favorable in lower temperature and will be decreased by increasing temperature from 20 to 50°‌C.