| Lead compounds have a very wide range of applications for its outstanding performance, which has become the source of pollution of lead in industrial wastewater. Wastewater containing Pb2+ without treatment will lead to water pollution, and greatly endanger people’s health. Therefore, elimination of lead in wastewater has very important significance for both environmental protection and human health. At present, the common methods to process the wastewater containing lead ions are chemical precipitation, ion exchange technique, adsorption method, electrolytic route, membrane separation and so on. Compared with other methods, the adsorption method has some advantages, such as low running costs, no secondary pollution, and applying to treat the wastewater with trace lead ion. So this method has been widely used for treatment of wastewater containing heavy metals. In our country, feather, a kind of cheap natural resources with insolubility, complex morphology and high content of active groups, are particularly suitable as recyclable adsorption materials of lead ions. This not only has good economic benefits, but also has some environmental benefits.This topic firstly studies the absorption property, desorption performance, repeated adsorption and desorption performance of feathers on lead ions; Then the structure changes of feathers before and after modification is investigated, and the absorption performance of modified feathers on lead ions was studied as well. Finally feathers were made into filter cartridge. The filtration performances and the dynamic adsorption performances on lead ions of three kinds of filter cartridge were measured.After a series of researches, conclusions are as follows:(1) Feathers showed better desorption property when it was treated by NaOH solution, in compared with Na2S solution. The optimum desorption conditions are:the desorption time of 60min; the concentration of NaOH solutions is 30mmol/L, the temperature of 40℃.(2) After repeated adsorption and desorption for 12 times, feathers still have good adsorption property and desorption performance.(3) After modified by sodium metabisulfite and carbamide, the surface membrane layer and cortical layer of feathers are damaged, feathers become slim. In addition, more a-helical conformation appeared after feathers were treated by sodium metabisulfite and carbamide.(4) Compared with original feather materials, the adsorption performance of modified feathers on lead ions is improved significantly, and as the quality of sodium metabisulfite increases the adsorption capacity of modified feathers on lead ions increases firstly and then decreases.(5) Feather/PP and modified feather/PP filter cartridge has good process-ability. The results show that the water flow speed and pressure increase with the increasing of adsorption time, which means it takes more time to stabilize the whole filtration system because of the bad wettability of feather fibers.(6) The cyclic and dynamic adsorption performances on lead ions of three kinds of filters are evaluated. The results show that feather/PP filters and modified feather/PP filters with more content of feathers or modified feathers shows better cyclic and dynamic adsorption performances. Among them, the dynamic adsorption performance of modified feather/PP filters is best.Modified feather fiber is a promising material used for water filtration and lead ions adsorption. |
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