| Every year,a large amount of industrial wastewater and domestic sewage are discharged into the environment due to improper treatment,which not only causes environmental pollution,but also violates China's sustainable development strategy.In this paper,using the idea of“treating waste by waste”,the use of metallurgical dust as raw material to prepare inorganic polymer flocculant to adsorb heavy metal ions is beneficial to solve the environmental pollution problem and realize the high added value utilization of metallurgical dust.The raw material for the preparation of this project is the metallurgical dust discharged from the steel plant,and the polyaluminum ferric chloride?PAFC?is prepared by the acid leaching-polymerization two-step method.X-ray diffraction analysis of the presence of aluminum and iron in the dust,consult the relevant literature,select the main factors from the many factors affecting the leaching of iron and aluminum from the dust,study the effects of various factors on the leaching of iron and aluminum in the dust,select the best The process combination parameters fully leached the iron and aluminum elements in the dust,and then the PAFC flocculant was obtained by adding the alkali liquid to the dust leaching solution to obtain the PAFC flocculant,and its physicochemical properties and application characteristics were characterized.The main conclusions are as follows:In the process of leaching iron and aluminum from metallurgical dust,the optimum conditions for acid leaching are temperature 80?,hydrochloric acid concentration is 5 mol?L-1,liquid-solid ratio is 10:1,acid immersion time is 25 min.Scanning electron microscopy and field emission scanning electron microscopy analysis of PAFC flocculant showed that the composition of PAFC flocculant is a network structure formed by interlacing chain oligomers.X-ray diffraction analysis shows that PAFC is not a simple mixture of aluminum-iron polymer,but forms an amorphous polymer.The characteristic peak of PAFC is studied by infrared spectroscopy.PAFC also contains polyhydroxy bridged aluminum.And high molecular polymers of iron.The optimal combination parameters of PAFC flocculant synthesis were studied by using methylene blue pigment and heavy metal ion removal rate as evaluation indexes.The results are as follows:under the condition of alkalinity of 1.5 and aluminum to iron ratio of 5:5,under the condition of 40 mg·L-11 methylene blue solution as standard,the dosage of PAFC is 25 mg,and the removal rate of 50mL of methylene blue solution can reach 90%;the degree of alkalinity is 1.5,the molar ratio of aluminum to iron is 9:1,and the dosage of PAFC is 15mg under the condition of 50mg·L-11 heavy metal ion solution,and 50mL Cu2+solution is removed.The rate can reach 60.24%,the PAFC dosage is 25mg,the removal rate of PAFC to50mL Pb2+solution can reach 71.42%,the dosage is 15mg,and the removal rate of PAFC to 50mL Cd2+solution can reach 56.02%. |
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