Adsorption Performance Of Sludge Activated Carbon On Ni And Tetracycline In Sludge Water Treatment Plant

The sewage sludge of water purification plant was direct discharged to water or untreated landfill will cause environmental pollution.The use of sludge from water purification plant to prepare activated carbon can adsorb pollutants in water and play the role of waste treatment.In this paper,sludge activated carbon was prepared by chemical activation using sludge from the water treatment plant as raw material with reed straw as carburizing agent.Activated charcoal was prepared with zinc chloride,sodium hydroxide and phosphoric acid as activators.The activated charcoal prepared with zinc chloride as activator had higher iodine value.The effect of preparation conditions on the adsorption value of activated carbon iodine was studied by orthogonal experiment.The order of influence was: reed addition ratio> activation temperature> activator concentration> activation time> solid-liquid ratio;the optimum conditions for the preparation of activated carbon for sludge were obtained by single factor experiment: the reed addition ratio was 20%,the activation temperature was 600 °C,the activation time was 50 min,the activator concentration was 3 mol/L,and the solid-liquid ratio was 1:2.5.The sludge activated carbon iodine value was 653.1mg/g under the optimum conditions.The activated charcoal prepared from sludge was characterized by scanning electron microscope(SEM).Compared with the original sludge,the specific surface area of activated carbon was increased and the adsorption site increased accordingly.The specific surface area and pore diameter analysis showed that the sludge activated carbon had a significant increase in pore size,pore size distribution,and pore volume,and the specific surface area of sludge activated carbon reaches 151.9m2/g.FTIR showed that activated carbon from sludge had a variety of oxygen-containing functional groups,which was conducive to the adsorption ofnickel ions and tetracycline.The activated carbon has a good adsorption effect on nickel ions and tetracycline.The maximum adsorption capacity for nickel ions was 26.92mg/g,and the maximum adsorption capacity for tetracycline was 153.4mg/g.The effect of activated carbon on the adsorption of nickel ions and tetracycline was greatly influenced by the pH value,and the acid condition was beneficial to the adsorption of tetracycline,and the alkaline condition was beneficial to the adsorption of nickel ions.The pseudo-second-order kinetic model can better reflect the adsorption characteristics of sludge-activated carbon on nickel ions and tetracycline than the pseudo-first-order kinetic model.In addition,the Langmuir isotherm model was more suitable than the Freundlich model to describe the sorption isothermal characteristics of activated carbon for nickel ions and tetracycline,and their adsorption behavior on activated carbon was monolayer adsorption.