Defluorination behavior of modified nano-bentonite in zinc sulfate solution

An experimental study on treatment of fluoride in zinc sulfate solution by modified nano-bentonite was carried out in this study. Nano-Bentonite was used as an adsorbent and modified with lanthanum nitrate. The influences of modified nano-bentonite, adsorption time, temperature and pH on removal of fluoride were also studied. Scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX) and Fourier-transform infrared spectromxetry (FTIR) were used to characterize the adsorbent before and after modification. Results showed that the concentration of fluorine dropped from 100 mg/L to 45.64 mg/L, which conformed to the provisions by industrial production of less than 50 mg/L when modified nano-bentonite being added is 10 g/L, Adsorption time being 15 min, at 40 °C and pH 5. Variety of analytical tools showed that the lanthanum element payload on the surface of the nano-bentonite after the modification increased at the same time, including the interlayer spacing of nano-bentonite and specific surface area, thereby improving the fluoride removal performance of nano-bentonite greatly.