Effect Of Modified Rice Husk Based Activated Carbon On Removal Of Total Phosphorus In Wastewater

The eutrophication of lakes and rivers caused by nitrogen and phosphorus has become one of the most urgent environmental problems in the world.Among many phosphorus removal technologies,the adsorption method has attracted much attention due to its fast adsorption rate,small amount of sludge,simple operation,low cost and environmental friendliness.In this study,the total phosphorus content in the water was marked out in the first grade B of a sewage plant in a county in southern yunnan,and water samples were simulated for water distribution in schools.The main research results are as follows:(1)The experiment the optimum preparation conditions of rice husk charcoal is:the carbonization temperature is 200℃,with ZnCl2 activation method,impregnation ratio was 1.5:1,the activation temperature is 300℃,the activation time of 40~60 min,the preparation of rice husk charcoal adsorption performance is best,total phosphorus removal rate was 61.18%.(2)The adsorption capacity was ranked as follows:HCl+supported by1:100 chitosan modified(76.82%)>HCl modified(73.26%)>NaOH modified(61.26%)and>unmodified rice husk carbon(61.18%).The Langmuir isothermal equation(R~2=0.9982)was better than Freundlich isothermal equation(R~2=0.9398).The experimental results were consistent with the Langmuir isothermal equation,which was y=4.8533x+0.1108.(3)Modification of the appearance of the rice husk carbon analysis,scanning electron microscope(SEM),X-ray diffraction analysis(XRD),Fourier transform infrared spectrometer(FTIR),automatic analyzer(BET)surface characterization analysis:using HCl+load chitosan composite modified rice husk charcoal surface coarse pore developed,specific surface area is 642.2 m~2/g,greatly entrance is 0.31 cm~3/g,has the rich in the pore,micropore structure and characteristics of activated carbon.(4)Static adsorption experiment through the detection of rice husk based activated carbon in different dosing quantity,initial pH value,oscillating time and reaction temperature on the removal rate of total phosphorus,total phosphorus in the initial concentration of 2 mg/L,rice husk carbon adsorption removal of phosphorus in the best experimental conditions for static:rice husk charcoal dosing quantity for 4 g,pH=6.4,the oscillation for 40 min,the reaction time reaction when the water temperature is 16℃above,rice husk carbon to total phosphorus removal rate was 86.12%,total phosphorus concentration is 0.28 mg/L water.(5)Dynamic adsorption experiments were conducted to study different inlet flow rates and filter layer thickness,and the change of total phosphorus concentration of effluent with time was used to draw the penetration curve.Rice husk charcoal adsorption removal of phosphorus in the best dynamic experimental conditions for:room temperature 25℃,the adsorption column diameter is 100 mm,the filter layer thickness of 0.6 m,the water flow rate of 4 ml/min,penetration time of 510 min,the saturation time of 660 min.In the adsorption and regeneration experiment,the NaOH solution of 1.0mol/L was selected as the desorption agent.The adsorption capacity of phosphorus was 1.651mg/L,and the desorption rate was up to82.5%.Four regeneration experiments showed that the adsorption capacity of total phosphorus was 1.54mg/L~1.65mg/L,and the adsorption rate was77.1%~82.5%.(6)In order to study the practical application conditions of modified rice husk carbon,this experiment compared the removal effect of modified rice husk carbon and quartz sand with the sewage sampling experiment in a university park in kunming.The experimental results show that if modified rice husk carbon is added to the sand filter tank for adsorption,the average residual concentration of total phosphorus is 0.340mg/L,and the average removal rate of total phosphorus is more than 86.73%.Modified rice husk carbon adsorption method not only provides beneficial ideas for the utilization of resources,but also has great practical significance for the improvement of the standard of sewage treatment industry and the development of new high specific surface area activated carbon.