Study On The Preparation Of Straw Biochar And The Adsorption Efficiency Of Nitrogen And Phosphorus In Whastewater

In recent years,the problem of air pollution caused by a large number of straw waste incineration in recent years has become a difficult problem in the field of environmental management.How to deal with a large number of abandoned straw effectively and achieve its resources and energy has become an important research direction in the field of environment.The pyrolysis of crop straw at high temperature can produce biological charcoal with certain adsorption efficiency,which can not only deal with agricultural waste,but also realize the utilization of waste straw.Ammonia nitrogen and total phosphorus are important factors causing black odor pollution of water bodies.At present,the pollution of black and odor pollution in the rural and small towns is very serious,and the problem is still more prominent.It is necessary to further seek economic and effective technical means to achieve the proper treatment of nitrogen and phosphorus pollution in the black and smelly water bodies.The porous structure of biological carbon can achieve the removal of many kinds of pollutants.The application of straw bio carbon to the removal of nitrogen and phosphorus is not only conducive to reducing the cost,but also can provide a green and economical solution to the problem of nitrogen and phosphorus pollution in black and smelly water.In this paper,three kinds of crop straw,soybean straw,rice straw and corn straw were prepared from the common crop wastes in the north,and the biocharcoal materials were prepared by using ferric chloride solution.The physicochemical properties of the prepared materials were also characterized.The prepared bio carbon material was used as adsorption material to adsorb the ammonium ion(NH4+)and phosphate ion(PO43-)in water.The adsorption mechanism was analyzed,and the best carbon materials for the adsorption of NH4+ and PO43-in water were optimized.The physicochemical properties of three kinds of straw biochar materials and four modified straw biochar materials were characterized.After modification,the structure and function of biochar materials have changed.The surface of straw biochar is negatively charged.After modification,the surface of the biochar material is positively charged,and it is easier to coagulate inside the material.Straw biochar material has a certain amount of pore structure,but the modified biochar material has more pores and better effect on target adsorption.The best adsorption effect of straw bio carbon material to NH4+ is soybean straw biological carbon,the adsorption amount is 7.025 mg/g,and the best adsorption effect for PO43-is rice straw biological carbon,and the adsorption amount is 4.506 mg/g.The best adsorption effects of modified straw bio carbon materials on NH4+ and PO43-were modified soybean straw biological carbon materials,and their adsorption capacity was 9.550 mg/g and 6.390 mg/g respectively.The adsorption of NH4+ and PO43-by the prepared biochar as adsorbent was studied in laboratory.In the study of adsorption kinetics,the adsorption process of NH4+(PO43-)is better and the reaction rate constant is less than 1,whether it is straw biological carbon material or modified straw bio carbon material.The adsorption process of NH4+(PO43-)is better.Isothermal adsorption experiments showed that the adsorption of NH4+ on soybean straw biochar material was chemisorption on the solid surface.The adsorption of rice straw biological carbon material and maize straw bio carbon material to NH4+ is between the single molecular layer and the multi molecular layer,and the surface inhomogeneity of the adsorbed material will affect the adsorption process.The isothermal adsorption experimental study of PO43-showed that both straw biological carbon material and modified straw bio carbon material were consistent with the Langmuir isothermal adsorption model,and R2 was more close to 1.The innovation point of this paper is to make the common agricultural waste soybean straw in the north as one of the raw materials and the rice straw and corn stalk to prepare biological carbon,and to use the ferric chloride solution to modify it,and use the prepared biological carbon material to treat the nitrogen and phosphorus pollution in the black and smelly water body,which will be used for the resource utilization of agricultural waste in the future.The basis is provided.