Preparation Of Gelatin-modified Nanoscale Iron And Removal Of Methyl Orange

Nanoscale iron that has large specific surface area and high reactivity has beensuccessfully applied for the remediation/treatment of soil, groundwater andwastewater contaminated with chlorinated organic compounds, nitroaromaticcompounds, arsenic, heavy metals, nitrate, dyes and phenol. But nanoscale iron iseasy to agglomerate to form larger particle, which reduces its reactivity and stability.To improve the reactivity and stability of nanoscale iron, this paper selectedgelatin as modifier to prepare gelatin-modified nanoscale iron and used it to removemethyl orange. This paper studied the preparation conditions of gelatin-modifiednanoscale iron, the removal efficiency and mechanisms of methyl orange bygelatin-modified nanoscale iron. We get the following conclusions:(1) The preparation conditions of gelatin-modified nanoscale iron:100mL ofsolution (ethanol/water=1/1) containing0.4964g of FeSO4·7H2O was added into a500mL three neck flask. The solution was bubbled with nitrogen for30min toremove dissolved oxygen. Then50mL of solution (40℃) containing0.1g of gelatinwas added into the three neck flask. The mixture was stirred for30min. Underconstant stirring,50mL of solution containing0.2366g of KBH4was addeddropwise to the mixture by a separatory funnel. After addition of all of the KBH4solution, the stirring was continued for20min to obtain gelatin-modified nanoscaleiron. The whole process was under nitrogen atmosphere.(2) Compared with unmodified nanoscale iron, the dispersion and stability ofgelatin-modified nanoscale iron was improved. The interaction between gelatin andnanoscale iron may be the coordination between iron atom and amino nitrogen atomor hydroxyl oxygen atom in gelatin.(3) The removal efficiency of methyl orange by gelatin-modified nanoscale ironwas higher than that by unmodified nanoscale iron. The removal efficiency decreased with the increase of initial concentration of methyl orange, initial pH valueand content of dissolved oxygen, but increased with the increase of modifiednanoscale iron dosage and temperature. NO3-and CO32-inhibited the removal ofmethyl orange. The effect of SO42-on the removal was related to its concentration.(4) According to UV-Vis spectra, the products may contain sodium sulfanilate.The removal mechanisms of methyl orange by gelatin-modified nanoscale iron maybe adsorption and reduction.