Ultrafast advanced treatment of chromium complex-containing wastewater using Co/Fe layered double hydroxide

Abstract

Various industrial wastewaters contain chromium complexes. After traditional chemical precipitation treatment, free trivalent chromium ions can be removed, but the chromium complex remains in the effluent. Therefore, advanced treatment of these types of wastewater is urgently needed. A cobalt/iron carbonate layered double hydroxide (Co 2 Fe 1 -CO 3 -LDH) was synthesised in this study as an adsorbent to remove chromium citrate complexes. After treatment, the total chromium could be reduced from 20.8 mg/L to less than 1.5 mg/L. The adsorption process has good performance over a wide range of temperatures and pH values. Moreover, the adsorption rate was exceptionally high. The adsorption capacity of the adsorbent reached 75.5%, 81.5%, and 81.1% of the equilibrium adsorption capacity within 1 min. This research demonstrated that layered double hydroxide (LDH)-based materials have great potential for use in advanced treatment of chromium complex-containing wastewater. • As adsorbent, the synthesis process of layered double hydroxide is relatively simple. • The adsorption capacity of the Co 2 Fe 1 -CO 3 -LDH is little affected by pH value and temperature. • The adsorption removal of chromium citrate complex by Co 2 Fe 1 -CO 3 -LDH is really fast.