Effects Of Sulfamethazine On Colloid Transport Under Different Environmental Conditions

Biochar is a stable carbon-rich product formed by the thermal cracking of biomass such as agricultural and forestry wastes under anoxic conditions.It was originally used to describe an activated carbon prepared from sorghum that adsorbs harmful gases.In northern China,corn and wheat are the most commonly grown food crops,which straw is the main agricultural waste.The application of these straws as biochars as fertilizers or soil amendments to the soil can solve the pollution problems of agricultural wastes while reducing carbon emissions,and has great application prospects.Kaolin is a kind of clay mineral in soil,soft and greasy,relative density 2.4-2.6,high refractoriness,up to 1700~1790°C,low plasticity,low adhesion,good insulation and chemical stability.Sulfamethazine(SM2)is a kind of sulfa antibiotic which belongs to a broad-spectrum antibacterial drug and has broad antibacterial spectrum and strong curative effect.It is widely used in the prevention and treatment of various bacterial infections in humans,livestock and aquaculture.However,when sulfa antibiotics enter the human body,they will remain in the body and accumulate,destroy the human hematopoietic system,cause hemolytic anemia,and even have the potential for carcinogenesis.In this dissertation,isothermal adsorption experiments of wheat biochar fired at different temperatures(WB300 and WB600)and SM2 at different pH conditions were performed to study the adsorption characteristics of biochar on SM2;Studing on transport and retention of WB300,WB600 adsorpting SM2 at different pH conditions;Studing on transport and retention of kaolinite and SM2 at different ionic strengths,and combining DLVO theory to elucidate their retention mechanism in porous media.The isothermal adsorption experiments of WB300,WB600 and SM2 under different pH conditions shows: when the pyrolysis temperature is 300°C,the maximum adsorption of SM2 by WB300 increases with the increase of pH.when the pyrolysis temperature is 300°C,with the increase of pH,the maximum adsorption of SM2 by WB600 increases gradually,and the effect is higher than the effect of pH on WB300.The transport and retention experiments of WB300,WB600 adsorpting SM2 at different pH conditions shows: in the same solution pH condition,when pH = 5 and pH = 7,as the concentration of SM2 adsorbed by WB300 and WB600 increases,the penetration decreases.When pH = 10,as the concentration of SM2 adsorbed by WB300 and WB600 increases,the penetration decreases.Under the condition of the same concentration of SM2 adsorbed by WB300 and WB600,the penetrating amount of WB300 and WB600 decreased as the pH of the solution increased.However,when the WB300 and the WB600 transport alone,the amount of penetration is less affected by the pH of the solution.The transport and retention experiments of kaolinite and SM2 at different ionic strengths shows: when the IS of the solution is 0.1 mM,SM2 has low migration in porous media.Kaolinite significantly promotes the migration of SM2 when kaolinite clay is present in the background solution.And SM2 slightly inhibits kaolinite colloidal migration,but the overall impact is small.when the IS of the solution increased from 0.1 mM to 10 mM,kaolinite colloids and SM2 penetration amount are significantly decreased.When the IS of the solution is 10 mM,HA enhanced the mobility of kaolinite and facilitated SM2.