Reseach On Preparation And Application Of Nano-α-FeOOH In The Water Treatment

With the expansion of human activities and intensification of the process of industrialization. The quality of water environment across China deteriorates and water sources being endangered by serious contaminations. It results contaminated water, water complex and all kinds of type and quantity of inorganic ions. Removal is poor that conventional water treatment deals with inorganic ions.So it is urgent to study, promote and apply efficient low-power green conventional water treatment. On the basis of the condition wu choose Nano-FeOOH, because there are super adsorption capacity, excellent flow stability, large surface area and higher density, adsorpting and depositing of the inorganic ions in environmental media and so on. Thus the synthesis of FeOOH application caused more and more interest by scientific research workers. In this study, prepared by chemical co-precipitation of aluminum doped with different percentage of nanoα-FeOOH, In this study, Using chemical co-precipitation method producted different percentage of Al doped nanoα-FeOOH, did the experiments of adsorption and flocculation in laboratory and disscus the reaction process and mechanism and then applied Cetian micro-polluted water treatment. In this thesis, the content and conclusions summarized as the following aspects:1)Preparation and modification of Al-doped nano-α-FeOOH flocculantsNano flocculants of Al-dopedα-FeOOH with different propotions were prepared;the performances of different nano-α-FeOOH flocculants were charactered by instuments such as transmission-electronic microscope, X-ray diffractometer, Laser Particle Size Analyzer. The results shows as follows: nano-α-FeOOH has a relatively complete crystal structure and narrow particle size distribution; it is uniformly dispersed and of the shape of needle-sized ;the grain size is 120×20nm; the greater the proportion of aluminum-doped, the better the distributed performance.2)The adsorption efficiency of Al-doped nano-α-FeOOHThe water samples containing fluorine and lead were absorbed by nano-α-FeOOH adsorbent , then the adsorption effeciency was studied. Test results showed that the adsorption efficiency of nano-α-FeOOH on lead or fluoride was influenced by pH of the system, the initial quality concentration of adsorbate, adsorption time and salinity.The saturated adsorption capacity of lead and fluoride under the condition of 30℃was 5.043mg/g and11.03mg / g respectively.3)The flocculation efficiency of Al-doped nano-α-FeOOHExperiments were also conducted with regard to removal of lead and fluoride from water sample containing fluorine, lead and water sample from the Cetian Reservoir through flocculation. The results shows that the flocculation efficiency of nano-α-FeOOH towards lead or fluoride was influenced by pH of the system, dosage of composite flocculant and salinity; various composite nano flocculants of Al-dopedα-FeOOH with different propotions have obviously different removal efficiencies when they were used in dealing with water in the Cetian Reservoir. The test results also showed that a fairly desirable removal efficiency could be reached when the nano-α-FeOOH flocculant of which the Al-Fe molar ratio is 0.15 was used; Under the condition that the dosage of composite flocculant was 200mg/L, the removal rate of Pb2+ and F-could be highter than 60% and 46% respectively.