Tetracycline Adsorption on Magnetic Sludge Biochar: Effects of pH, Humic Acid (HA), and Fulvic Acid (FA)

Natural organic matters (NOMs) are ubiquitous in the environment, but few systematic studies have examined the influence of NOMs on the sorption ability of magnetic sludge biochar. In this study, magnetic sludge biochar was synthesized, characterized, and used as a sorbent to remove tetracycline (TC) from aqueous solutions. The effects of pH, humic acid (HA), and fulvic acid (FA) on TC adsorption by magnetic sludge biochar were studied using batch experiments. Adding HA and FA can alter the adsorption behavior of TC, except for its pH dependency. The results of this study show that relatively low concentrations of dissolved HA (<= 8 ppm) and FA (<= 5 ppm) promote the adsorption capacity of TC, but higher concentrations compete against TC for sorption sites on the surface of magnetic sludge biochar. The results of this study promote a better understanding of the application of magnetic sludge biochar in real antibiotic wastewater.