Characteristics of Tetracycline Adsorption by Cow Manure Biochar Prepared at Different Pyrolysis Temperatures

This study aimed to explore the feasibility of using cow manure biochar (CMBC) for adsorption of tetracycline for realizing farm waste treatment and recycling. Three kinds of pyrolysis-temperature CMBCs were prepared and characterized. There were significant differences in the specific surface area, pores structure, surface charge, and oxygen-containing functional groups. The effect of adsorption was not only related to the physicochemical properties of CMBC but also the dosage, solution pH, and ambient temperature. CMBC showed surface heterogeneity, and the adsorption of tetracycline was mainly chemical. Controlling the rate of adsorption was achieved by combining internal particle diffusion and liquid film diffusion. Furthermore, the adsorption was a spontaneous and endothermic process. The use of CMBC as an adsorbent for tetracycline represents a new method for treating and recycling waste in farms. These results could aid in further studies on the adsorption mechanism and optimizing the adsorption process.