Effects Of Carbon Materials On Migration And Environmental Behavior Of Tetracycline In Soil And Water

Nowadays,tetracyclines(TCs)are widely used as growth promoters for livestock.Unfortunately,30%?90%of TCs cannot be absorbed and are excreated to soil or water through urine and feces,which posed potential risks to the ecosystem and human health.Carbon materials such as biochar,carbon nanotubes,etc.are widely used in many fields due to their excellent properties,which make them enter the environment via industrial and domestic waste.Eventually,it will affect the environmental behavior of antibiotics and other contiminants.For instance,biochar can alter the migration and transformation of TCs in soil.Additionally,advanced oxidation process(AOPs)which is widely used in the wastewater treatment can change the properties of carbon nanotubes(CNTs)and thus affect their adsorption capacity for TCs,heavy metals and other pollutants.TCs and was selected as typical pollutant in this work.We conduct a series of studies on the migration,transformation and removal of TCs in soil and water.The main results and conclusions are as follows:(1)Usually,biochar is applied to the soil as agricultural fertilizer and it will affect the environmental behavior of TCs and the structure of microbiome.Thus,we investigated the effects of biochar in the migration of TCs.TCs which mainly exist in surface soil are dissipated through strong adsorption such as surface complexation.Biochar promoted the migration of TCs to deeper layer of soil,and increased the relative abundance of copiotrophic bacteria such as Actinomycetes and Proteobacteria while decreasing that of Nitrospirae and Acidobacteria.Additionally,TCs reduced the relative abundance of major fungal phyla such as Basidiomycetes and Ascomycetes in soil,while biochar could absorb part of TCs and thus mitigate its effects on soil microbiome.(2)This work explored the operation of NTP and investigated its effects on the adsoption capacity of CNTs for TCs and other pollutants.Obviously,NTP has a strong ability to remove phenol and Cr(?)and there are synergistic effects in the removal of these two contaminants.NTP increased the oxygen-containing functional groups such as C=O and-COOH in the surface of CNTs,while promoting its electronegativity and its dispersion in water.The alteration of functional groups on the surface of CNTs has no significant effects on the adsorption of TCs,which was due to the hydrophilic and hydrophobic groups contained in the TCs molecules.In contrast,the adsorption capacity of CNTs for chloramphenicol increased and that for Cr(?)decreased after NTP treatment.