Dissertation > Environmental science, safety science > Processing and comprehensive utilization of waste > General issues > Wastewater treatment and utilization > Additives

The modified bentonite Preparation of Phosphate Removal addition to chromium

Author MeiXiangYang
Tutor PuHongPing
School Kunming University of Science and Technology
Course Environmental Engineering
Keywords Bentonite Modified Phosphorus Hexavalent Chromium
CLC X703.5
Type Master's thesis
Year 2007
Downloads 295
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In recent years, phosphorus cause eutrophication almost throughout each lake, and this trend is intensified to promote the rapid growth of algae in water to destroy the self-purification capacity of the water body. Some industrial sectors that generate wastewater containing hexavalent chromium distribution over an extensive daily discharged wastewater than the larger, however, the toxicity of hexavalent chromium, or even a small concentration would cause great harm to the environment and the human body. Therefore, water is increasingly being increasingly serious pollution, the development of processing of phosphorus wastewater and wastewater containing hexavalent chromium effective adsorbent treating wastewater discharge standards so that it is very necessary and very urgent. In this study, the use of bentonite unique structure and abundant, this feature of the objective conditions have to be processed into a cheap and effective adsorbent bentonite into a new method of effective adsorbent inorganic and organic modified using microwave heating. Adsorbent prepared by microwave heating compared with traditional methods, the most prominent advantages fast microwave heating materials warming, will shorten the reaction time of a few hours to a few minutes, greatly shorten the processing time of the sample. Inorganic lanthanum modified bentonite best preparation conditions are: concentration of sulfuric acid was 15%, and lanthanum chloride concentration of 0.4% soaking, soak the pH is above 10, the microwave irradiation power of 340 W, and the irradiation time for 5 min . Application experiments, phosphorus conditions: the impact of the most significant factors solution pH 3 to 6, the oscillation time of 60 min. Phosphorus removal rate reached 99.96%, the the phosphorus adsorption amount reached 24.99 mg / g, the solution residual phosphorus concentration of 0.02 mg / l. Optimal preparation conditions of organic lanthanum modified bentonite: water bath temperature of 60 ° C and 5% CTMAB modified concentration, microwave irradiation power of 166 W, irradiation time of 6 min. Phosphorus experiments, the most significant effect on the factor solution pH of 3 to 4, the oscillation time of 60 min. The phosphorus removal is 99.95%, the adsorption capacity was 41.64 mg / g the phosphorus residue concentration of 0.0262 mg / l. After organic modification, its effect on phosphorus adsorption increased about 60%. Titanium inorganic lanthanum modified bentonite optimum preparation conditions: a sulfuric acid concentration of 15%, La / Ti molar ratio of 6, and the mole of total 2.53mmol, soaking the pH is above 10. Best conditions in the experiments of the hexavalent chromium, hexavalent chromium: the impact of the most significant factors in the solution to a pH of 4 to 6, the oscillation time of 80 min. Hexavalent chromium removal rate of 87.64%, the adsorption capacity of 4.38 mg / g, and hexavalent chromium residue concentration of 3.71 mg / l. Organic lanthanum titanium modified expandable Stream the soil best preparation conditions: the water bath temperature of 60 ° C, CTMAB modified concentration of 6%. Experiments hexavalent chromium, the impact of the most significant factors in the optimal pH of the solution is 6, the oscillation time of 80 min. Hexavalent chromium removal rate is 90.72%, the adsorption amount to 6.80mg / g, the residual concentration of hexavalent chromium to 2.78mg / l. After organic modification, its effect on the adsorption of hexavalent chromium increased about 30%.

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