Advanced Treatment of Printing and Dyeing Wastewater by Adsorption Concentration-Fenton Oxidation Process

The combined process of adsorption concentration and Fenton oxidation technology was used for the secondary effluent treatment of printing and dyeing wastewater. The influencing factors of adsorbent dosage, adsorption time and pH value on the adsorption were studied. Moreover, the effects of Fe²⁺ concentration, H₂O₂ concentration, different dosing modes, reaction time, pH value of desorption solution, the conditioning reagent and the highest temperature in Fenton oxidation process were also investigated. It is shown that the best adsorption condition is as follows: adsorbent dosage 4 g·L^-1, pH value 7, and adsorption time 30 min. As for the concentrated solution after desorption, 0.1 mol·L^-1 of Fe²⁺, 2 mol·L^-1 of H₂O₂, dosing mode of trisection-adding, and reaction time of 1 hour are found to be the best Fenton oxidation condition. The combined process can reduce the amount of the wastewater and improve the biodegradability. So this method can be considered as an efficient process for the treatment of printing and dyeing wastewater.