| Arsenic contamination in water is important to the environment and human health and safety issues currently faced by many countries. Arsenic is widely present in the Earth’s environment, human activities such as mining and smelting and chemical production to make more and more transfer of arsenic into the water. Arsenic accumulation in human bodies, can cause skin cancer and damage to the liver and kidney function, severe to cause death. The chemical activity of the nano-titanium dioxide, non-toxic and low cost, has a good application prospect in water treatment. In view of this, based on the natural zeolite as the carrier, by the sol-gel method of modified zeolite nano-titanium dioxide, and studied its effect on the removal of arsenic in water, the main research results are as follows:1. Through the powder immobilized method to determine the optimum size of the zeolite powder is100～200mesh, three different methods of modified zeolite was studied in nano-titanium dioxide load factor, and determines the modified zeolite modification methods for NaOH-roasting joint. Modified in NaOH concentration is1.5mol·L-1, and calcination temperature500℃, under the processing for a quick modification zeolite.2. Experimental study on the sol-gel method of modified zeolite optimum technological conditions of nano-titanium dioxide, at room temperature, butyl titanate10mL, anhydrous ethanol50mL, acetic acid10mL,10mL of deionized water, pH adjustment system for3～4, under these conditions of the preparation of modified zeolite load nano-titanium dioxide.3. In the modified zeolite load nano-titanium dioxide for arsenic adsorption experiments, research loaded nano-titanium dioxide dosage, adsorption of pH,and adsorption time of arsenic absorption, the results show that the loaded nano-titanium dioxide dosage of10mg, oscillation adsorption time for20min, under the condition of pH of4, modified zeolite load nano-titanium dioxide for arsenic adsorption rate are more than92%, among them with NaOH-roasting joint modified zeolite load nano-titanium dioxide for arsenic adsorption rate is highest, the adsorption rate is above97%.4. The sol-gel preparation obtained nano-titanium dioxide mechanism characterization by X-ray diffraction instrument levy titanium dioxide particles and crystal type; surface morphology of the titanium dioxide particles observed by SEM, XRD diffraction analysis obtained when the calcination temperature400℃,2theta espectively were25.5°,37.9°,47.8°,53.8°and55.0°weak anatase crystal diffraction peaks appeared, when the temperature reaches600℃, the diffraction peaks of rutile TiO2(2theta espectively were7.7°,36.2°,41.5°,54.4°and57.0°), indicating that the rise of temperature promoted the titanium dioxide from anatase to rutile transformation. Experimental research is titanium dioxide anatase polymorph, because it has a good adsorption capacity. Therefore, the choice of500°C as the calcination temperature, the formation of anatase titania. The nano-titanium dioxide sample particle size less than100nm, there is a certain degree of reunion, and this phenomenon may be due to the temperature of the sintering process can be observed by SEM. And NaOH-roasting joint modified zeolite load TiO2particle size than a single large particle size of nano-titanium dioxide, which improves the lack of single nano-titanium dioxide in water treatment applications.5. Finally, it will be modified zeolite load nano-titanium dioxide evaluation for removal of arsenic in water, take the same amount of modified zeolite load nano-titanium dioxide, under optimum conditions, it is studied the arsenic adsorption rate of the simulated wastewater containing arsenic. Results obtained, NaOH modified zeolite load nano-titanium dioxide for arsenic adsorption rate was93.06%, the roasting of modified zeolite load nano-titanium dioxide to arsenic adsorption rate was95.22%, the NaOH-roasting joint modified zeolite load nano-titanium dioxide for arsenic adsorption rate was97.98%, and the single nanometer titanium dioxide for arsenic adsorption rate was90.94%, and shows that in the simulated arsenic wastewater treatment, can make the arsenic concentration of1mg·L-1arsenic waste water to industrial water discharge standards. NaOH-roasting joint modified zeolite load nano-titanium dioxide is relatively single nano-titanium dioxide for arsenic adsorption rate has greatly improved, and good adsorption effect, thus it can be seen, the modified zeolite load nano-titanium dioxide in the treatment of wastewater containing arsenic has a good application prospect. |
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