| Since the process of reform and opening up,industry and agriculture in China has been rapidly developed and has taken great progress.However,Dianchi Lake has suffered serious pollution because of lack of environmental awareness,which has producted a huge number of polluted sediment.The sediment has formed the important endogenous pollution in Dianchi Lake,which is releasing a large number of toxic and harmful pollutants to the water and continuously polluting Dianchi Lake.Therefore,the government started the project of dredged sediment,which can completely remove the endogenous pollution.The sediment that is dredged out of Dianchi concentrates nitrogen and phosphorus nutrients,heavy metalss organic matter and microorganisms.The sediment need be properly disposed,but common method of disposal to Dianchi Lake sediment is simple landfill now.This method which occupies a lot of land resources and makes second pollution has a series problems.Accordingly,it urgently need a scientific,effective and economical way to utilize the huge number of dredged sediment,that means turning waste into treasure.This research based on the emerging topic which is the resource utilization of Dianchi Lake sediment.The main chemical composition,mineral composition and heavy metals contents of Dianchi Lake sediment were analyzed by the Inductively Coupled Plasma Optical Emission Spectrometer(ICP-ES),X Ray Diffraction(XRD),atomic absorption spectrophotometer,visible spectrophotometer.The results show that the main chemical composition of sediment has a certain gap to and ceramsite component require.A high-performance water-absorbing ceramsite was prepared using Dianchi Lake sediments,fly ash and self-made expanding-agent mixture.The expanding-agent mixture caused the expanding effect to occur before and during the ceramsite calcining stage to increase the micropore and raise the water absorption capability.An L9(38)orthogonal experiment was designed to determine the optimal proportion of raw materials and the optimal calcining processes,which were further applied in calcining the ceramsite.At present,the peak water absorption of high-performance water-absorbing ceramsite is 66.71%and the average water absorption is 61.06%,while water absorption of similar ceramsites are between 10%-48%.These indicate that high-performance water-absorbing ceramsite is far better than similar ceramsites.The special properties of high-performance water-absorbing ceramsite was analysed by specific surface area analysis(BET),Scanning Electron Microscope(SEM),Inductively Coupled Plasma Optical Emission Spectrometer(ICP-OES),Fourier Transform Infrared Spectroscopy(FT?IR).The results show that high-performance water-absorbing ceramsite is full of micropore,specific surface area is 4.468 m2/g,and surface chemical functional groups almost are hydrophilic functional groups.It deeply analysis the mechanism of excellent water absorption.After the toxic heavy metals leaching test on the high-performance water-absorbing ceramsite,the concentration of toxic heavy metals conformed to the requirements of the Chinese national standard.It will not therefore cause secondary pollution.Water-absorbing ceramsite can be used in sponge city,agriculture,environmental protection.At the same time,according to high-performance water-absorbing ceramsite characteristics,researching basal applications.The extreme climate was simulated in laboratory.The high-performance water-absorbing ceramsite added to the soil and took water retention test.The high-performance water-absorbing ceramsite was taken to an adsorption test of simulated wastewater and an adsorption test of arsenic-containing wastewater.The results showed that the high-performance water-absorbing ceramsite can effectively improve the water retention property in soil.It is in practice to test the water retention of high-performance water-absorbing ceramsite in soil.The high-performance water-absorbing ceramsite has certain adsorption effect on TP in the simulated wastewater,but adsorption effect on NH3?N is weak.The high-performance water-absorbing ceramsite has excellent adsorption of arsenic-containing wastewater,arsenic removal rate of up to 98%.According to the special properties of high-performance water-absorbing ceramsite,the potential economic benefits,environmental benefits,social benefits in high-performance water-absorbing ceramsite are took a comprehensive analysis.The results show that the high-performance water-absorbing ceramsite has good economic benefits,environmental benefits and social benefits.It find a scientific and effective way to utilize the Dianchi Lake sediment. |
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