|
With oil and coal resources become increasingly depleted , oil and coal composition become more complex, some crude oil production and coal plant products arsenic content increased. Arsenide will seriously affect the processing of oil and coal , mainly for arsenic poison the catalyst . Many industrially used catalyst arsenide are very sensitive to even a few hundreds of ppb ppb of arsenic poisoning the catalyst can be deactivated , and the higher the concentration of inactivated arsenide faster . Similarly arsenic wastewater would cause serious water and soil pollution , and ultimately through the food chain or surface water, groundwater enters the body and endanger human health. Therefore, the study carried out without delay arsenic removal , research, development and dearsenic efficient and economical method of arsenic removal , recycling where arsenic resources , so that turning waste into treasure, with significant social , economic and environmental significance. In this thesis, respectively sulfide , ferrous sulfate and ferric sulfate as a precipitating agent arsenic compounds in waste removal effects of reaction pH, reaction time, reaction temperature and other process conditions on the effect of arsenic removal . The results showed that: sodium sulfide precipitate arsenic removal reaction pH 6 , the reaction time was 20 min, the temperature at 40 ℃ , in addition to the best effect of arsenic , the maximum rate of 92% in addition to arsenic , arsenic arsenic removal solution after less than 150ppb. Aging time 180min , except there is no significant change in rates of arsenic , aging temperature of 40 ℃, the maximum rate of 94% in addition to arsenic , arsenic content control 80ppb or less. Arsenic removal reaction of ferrous sulfate precipitation at pH 9 , reaction time 300min, the temperature at 40 ℃ , Fe / As is 3, can get the maximum of 80% of arsenic , the solution can be reduced to 200ppb arsenic or less. The two precipitation reaction for oxidation treatment is not required before , but due to the trivalent arsenic and iron pentavalent arsenic removal results vary greatly , so that the reaction is required before the oxidation of arsenic . Ferric sulfate precipitation method optimum conditions , pH = 10, the temperature at 20 ℃, Fe / As of 4 , the reaction time was 150min. Ferric maximum arsenic removal arsenic removal was 90% , the average content of arsenic in the solution can be reduced to 100ppb or less.
|