Adsorption of Methylene Blue by Coal-Based Activated Carbon in High-Salt Wastewater

High-salt printing and dyeing wastewater is a difficult industrial wastewater to treat. Coal-based activated carbon (CBAC) can be used as an adsorbent to treat high-salt printing and dyeing wastewater and realize the resource utilization of CBAC. In this study, simulated wastewater that contained methylene blue (MB) was used as the research object, and CBAC was used as the adsorbent. The effects of CBAC dosage, NaCl concentration, coexisting ions, adsorption time, MB concentration, humic acid concentration, and solution pH on the adsorption performance of CBAC with MB were discussed. The results showed that when the CBAC dosage was 0.6 g/L, the solution pH was greater than 6, the adsorption time was 8 h, the adsorption temperature was 308 K, and the MB concentration was 10 mg/L. Thus, the maximum adsorption capacity of CBAC with MB was obtained. The maximum adsorption capacity and removal rate were 15.5 mg/L and 90%, respectively. High-salt wastewater can inhibit the adsorption of methylene blue by coal-based activated carbon. In addition, 20 g/L of NaCl reduced the adsorption capacity of coal-based activated carbon by 1.8 mg/g. Compared to the other coexisting ions, the influence of the presence of Cu2+ and Fe3+ on the removal of methylene blue was greater. However, when Cu2+, Fe3+ and high-salt wastewater coexist, the inhibition effect decreases.