A novel technique of flue gas desulphufization （FGD） using industrial sodium sulfide as absorbent is described to remove SO2 in flue gas. The FGD byproduct in this novel technique is sodium thiosuffate （Na2S2O3 ...A novel technique of flue gas desulphufization （FGD） using industrial sodium sulfide as absorbent is described to remove SO2 in flue gas. The FGD byproduct in this novel technique is sodium thiosuffate （Na2S2O3 · 5H2O, Hypo） which can be used as chemical raw material. Optimal operating parameters about this technique have been determined. In order to enhance productive efficiency of sodium thiosulfate, EDTA disodium additive is added into absorption solution to prevent oxidation of sodium thiosulfate. Its optimal concentration is 0. 02 wt. %. The pH value of absorption solution is set in the range of 5 ~ 6.5. Experimental results show that SO2removal efficiency averagely reach 98.72 %. The highest productive efficiency of sodium thiosulfate reaches 83.24 %. The sodium thiosulfate formed during FGD can be separated from saturated absorbent by filtration, concentration and crystallization. The filtrate after separating sodium thiosulfate will be reused as SO2 absorbent by replenishing some fresh sodium sulfide.展开更多
Fine soil generated from the soil washing process can be the second problem, as contaminants are concentrated in the fine soil, and also took the difficult forms to treat because soluble and exchangeable fractions are...Fine soil generated from the soil washing process can be the second problem, as contaminants are concentrated in the fine soil, and also took the difficult forms to treat because soluble and exchangeable fractions are already removed by soil washing process; therefore, the fine soil is indicated to hazardous waste, and discarded in hazardous waste landfill. Thus, this research would be performed that arsenic and heavy metals formed difficult to remove in the fine soil were converted to more treatable fractions with chelating agents. Moreover, feasibility study to apply the second remediation targeted to the fine soil inquired. As a result, the chelating agent was decided 50 mM Na2EDTA, and it could develop the complex. In addition, the result of sequential extraction showed that Mn/Fe-oxide fraction, comprised about 28% of amount at first, was decreased about 16%, and organic fraction, consisted approximately 20%, was also decreased about 11%, while exchangeable fraction and carbonate fraction were increased. This result means that the difficult fractions removed could change fractions） by chelating agent. This research can provide the possibility hazardous waste because of difficulty to remediate. the more treatable fractions （exchangeable and carbonate to treat the fine soil, although the fine soil was regarded to展开更多
基金This research project was sponsored by National Natural Science Foundation (20877026)
文摘A novel technique of flue gas desulphufization （FGD） using industrial sodium sulfide as absorbent is described to remove SO2 in flue gas. The FGD byproduct in this novel technique is sodium thiosuffate （Na2S2O3 · 5H2O, Hypo） which can be used as chemical raw material. Optimal operating parameters about this technique have been determined. In order to enhance productive efficiency of sodium thiosulfate, EDTA disodium additive is added into absorption solution to prevent oxidation of sodium thiosulfate. Its optimal concentration is 0. 02 wt. %. The pH value of absorption solution is set in the range of 5 ~ 6.5. Experimental results show that SO2removal efficiency averagely reach 98.72 %. The highest productive efficiency of sodium thiosulfate reaches 83.24 %. The sodium thiosulfate formed during FGD can be separated from saturated absorbent by filtration, concentration and crystallization. The filtrate after separating sodium thiosulfate will be reused as SO2 absorbent by replenishing some fresh sodium sulfide.
文摘Fine soil generated from the soil washing process can be the second problem, as contaminants are concentrated in the fine soil, and also took the difficult forms to treat because soluble and exchangeable fractions are already removed by soil washing process; therefore, the fine soil is indicated to hazardous waste, and discarded in hazardous waste landfill. Thus, this research would be performed that arsenic and heavy metals formed difficult to remove in the fine soil were converted to more treatable fractions with chelating agents. Moreover, feasibility study to apply the second remediation targeted to the fine soil inquired. As a result, the chelating agent was decided 50 mM Na2EDTA, and it could develop the complex. In addition, the result of sequential extraction showed that Mn/Fe-oxide fraction, comprised about 28% of amount at first, was decreased about 16%, and organic fraction, consisted approximately 20%, was also decreased about 11%, while exchangeable fraction and carbonate fraction were increased. This result means that the difficult fractions removed could change fractions） by chelating agent. This research can provide the possibility hazardous waste because of difficulty to remediate. the more treatable fractions （exchangeable and carbonate to treat the fine soil, although the fine soil was regarded to
