Synthesis Of Iron And Manganese Oxides Fixation And Their Ability To Remove Arsenic In Aqueous Solution

Water pollution is one of important challenges which matter environment and human health. Dangerous arsenic concentration in natural waters is now a worldwide problem. Development of efficient and convenient adorbent is an effective way to solve this problem. Iron and oxide of iron is one of most common use adsorbent since they pocess the high adsorption ablities at the low cost. What’s more, they could oxide As(Ⅲ) into As(Ⅴ). The ideal adsorbent for removing arsenic should pocess the properties high adsorption capacity, high selectivity, synchronous removal of As(Ⅲ) and As(Ⅴ), low cost, no-secondary pollution and renewability. The partical of iron oxide is so small to collection and its fixation can avoid its secondary pollution, which is the future trend of removing arsenic technology. Therefore, this article was aiming to prepare the novel adsorbent of loading impregnated iron and manganese oxides(FMBO) and magnetic iron and manganese(Mag-FMBO) to solve the problem of arsenic treatment in water.Duing the characteristics of excellent biocompatibility and biodegradability, nature saccharide become one of ideal loaded materials. Konjac glucomannan(KGM) is a kind of natural neutral hydrophilic polysaccharide from the tuber of amorphophallus konjac plant. Adding a certain amount of alkali into KGM to remove the acetyl groups that attached to the saccharide units followed by heating the mixture and freeze-drying could form the decetylated konjac glucomannan aerogels. Poor mechanical strength of pure KGM aerogels hindered their application as environmental materials. Therefore, this article was aiming to prepare KGM-based aerogels as FMBO loaded material to provide the solution of arsenic-contaminated water.The main results were as follows:1. We successfully prepare a hybrid material which impregnated iron and manganese oxides(FMBO) into deacetylated konjac glucomannan(Da-KGM) and sodium montmorillonite(Na+-MMT) aerogels matrix to remove As(Ⅲ) and solve the problem of secondary pollution caused by FMBO powder. Aerogels were prepared by coupling sol-gel processing to suitable freeze drying, which consisted of different weight ratios of FMBO to KGM, in the range of 0-1.5. The characterization of aerogels adsorbents with respect to crystallinity, functional group, morphology and thermostability were used XRD, FTIR, SEM and TGA-DTG, respectively. Porous aerogels have high-surface-area which are considered extremely attractive materials as adsorbents. The adsorbents were tested under different experimental conditions where the effect of contact time, pH and temperature were investigated. The maximum As(Ⅲ) uptake capacity reached 30.33 mg g-1 at the FMBO/KGM ratio of 1.5:1 at pH 7 and 323 K. Moreover, X-ray photoelectron spectroscopy(XPS) analysis results of compound aerogels before and after reaction with arsenic confirmed the mechanism for arsenic uptake by aerogels adsorbents.2. We successfully prepare a hybrid material which impregnated magnetic iron and manganese oxides(Mag-FMBO) into deacetylated konjac glucomannan(Da-KGM) and sodium montmorillonite(Na+-MMT) aerogels matrix to remove As(Ⅲ). The obtained aerogels were using compression test, thermo gravimetric analysis(TGA), vibrating sample magnetometer(VSM), X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR) and scanning electron microscope(SEM) to evaluate the mechanical and magnetic property, thermal and structure characteristic. The obtained adsorbents were tested under different experimental conditions where the effect of contact time, pH and temperature were investigated. The obtained aerogels M1.5 demonstrated a highest arsenite adsorption capacity of 13.30 mg g-1 under pH 7(323 K). Besides, the magnetic composite aerogels can be repeatedly used after the treatment of regenerant(NaOH/NaCl/Na ClO solution).3. We successfully prepare a hybrid material which impregnated iron and manganese oxides(FMBO) into deacetylated konjac glucomannan(Da-KGM) and grapheme oxide(GO) aerogels to solve the problems collection difficulties of nano-particle. The obtained aerogels were using compression test, thermo gravimetric analysis(TGA), X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR) and scanning electron microscope(SEM) to evaluate the mechanical property, thermal and structure characteristic. Bath experiment were used to acess the adsorption capacity of As(Ⅲ) and As(Ⅴ). The obtained adsorbents were tested under different experimental conditions where the effect of contact time, pH and temperature were investigated. The obtained aerogels Da-KGM/10%GO/FMBO demonstrated a highest arsenite [As(Ⅲ)] and arsenate [As(Ⅴ)] adsorption capacity of 30.21 mg g-1 and 12.08 mg g-1 under pH 7(323 K) respectively.