Preparation Of Fe-modified Activated Carbon Fiber And Its Applications For Fenton Degradation Of Rhodamine B And Adsorption Of Fluoride

Advanced oxidation processes (AOPs) could produce strong oxydic free radicalssuch as hydroxyl radicals and it is used in treatment of wastewater which is notbiodegradable well. As one method of AOPs，Fenton reaction has a lot of advantages.The cost of original materials is low, the process is easygoing and the efficiency ishigh. So it is widely researched and applied in many fields. Compared withtraditional Fenton system, heterogeneous Fenton system would broaden the scope ofpH and reduce iron ion hydrolysis in a way. Activated carbon fiber (ACF) has largespecific surface area and abundant micropores and is an ideal carrier to supportvarious iron compounds. This paper does a little research on preparation andperformance of Fe-modified activated carbon fiber (ACF-Fe). The catalytic propertyis evaluated by the degradation of RhB and the absorptive property by the removalof fluoride.In situ synthesis method and two-step physical and chemical activation were usedto prepare Fe-modified activated carbon fiber.The as-prepared samples werecharacterized by X-ray diffraction (XRD), scanning electron microscopy (SEM),Nitrogen adsorption-desorption, Fourier transformation infrared (FT-IR)spectroscopy, Raman spectrum (RS), X-ray photoelectron spectroscopy (XPS) andICP-AES. XRD, SEM and XPS analysis confirm the existence of the Fe3O4nanoparticles in the ACF-Fe catalyst. The content of Fe in the sample isapproximately8.0%. Nitrogen adsorption-desorption analysis showed that thespecific surface area could reach432m2/g and it is a kind of microporous material.FT-IR analysis shows that it has abundant functional groups. RS analysis proves thesample is amorphous carbon materials.The catalytic property of ACF-Fe was evaluated by the discoloration and chemicaloxygen demand (COD) of RhB in photo-Fenton and Fenton system, respectively.The reaction conditions, initial pH, H2O2dosage and other factors were investgatedin the experiments. The experiments showed that the catalyst had good catalyticeffect on the degradation of RhB (100mg/L).It was found that alkaline condition ispreferred to neutral and acidic conditions in the results of degradation. Under the condition of pH=13, the discoloration removal of RhB was over95%and the CODremoval of RhB was over75%in ACF-Fe/H2O2system after degradation for120min. The catalyst still showed good catalytic properties and catalytic stabilities afterbeing recycled for five times. FT-IR and XPS were used to examine catalyst beforeand after reaction. A possible mechanism was proposed by testing the hydroxylradicals. The results of adsorption experiments showed that the ACF-Fe had betteradsorption properties for low concentrations of fluoride in the aqueous solutions andhigh concentrations ineffective, the fluoride removal could reach54%.