A New Montmorillonite-Based Porous Composites: Effectively Removal of Cr(III)-Organic Complexes in Tannery Wastewater

Montmorillonite-based porous adsorbent prepared by gel casting method was used to adsorb Cr(III)-organic complexes in tanning wastewater,together with the initial concentration of 10 mg L−1. The as-porous adsorbent exhibited an excellent performance of separation. Meanwhile, its structural and morphology were characterized by TG, BET, XRD, SEM, EDS and XPS, showing that the porous adsorbent was complete hollow ball structure. And the adsorption results showed that the adsorption amount of porous adsorbent rapidly declined from 9.58 to 5.28 mg L−1, and only Cr(III) was adsorbed, when the molar ratio of Cr(III) and citrate was more than 1:5. Increased of pH was beneficial to adsorb Cr(III)-citrate in range from 2.46 to 7.12. Furthermore, the best removal efficiency of Cr(III)-organic complex was up to 97% and still above 84% after five cycles with porous adsorbent. Finally, the mechanism on adsorbing Cr(III) with porous adsorbent is also provided. Therefore, a kind of porous adsorbent which was easily separated, was prepared to deeply treat tanning wastewater containing Cr(III)-organic complex, and solve the problem of difficult recycle.