Effects of divalent metal cations and inorganic anions on the transport of tetracycline in saturated porous media: column experiments and numerical simulations

Abstract

Tetracycline is one of the most commonly used antibiotics in the world.

Transport of tetracycline in saturated porous media: combined functions of inorganic ligands and solution pH

“…In this work, the transport process of TC in the quartz sand column was described by the two-site nonequilibrium transport model using the CXTFIT 2.1 code. 12,18,51,52 This model was expressed an equilibrium site (Type 1 site) and a kinetic site (Type 2 site). 53 The model can be explained in eqn ( 4)- (10).…”

“…Note that TC molecules could contact aquifer media via multiple interactions including cation exchange, electrostatic interaction, and surface complexation during antibiotic transport. 12,14,[58][59][60] Considering the low CEC values of quartz sand (1.3 meq/100 g), the cation exchange effect played a negligible role in the mobility of TC. 61 The observed transport behavior was mainly attributed to the electrostatic interaction between TC molecules and sand grains.…”

“…Thus, phosphate played the most important role against TC deposition on porous media because of the greatest competitive deposition effects as mentioned earlier. 12,32,68,73 Thirdly, ligands with greater molecular sizes may show larger surface coverage on sand grain surfaces. As shown in Table 2, phosphate has a larger molecular size than the other two inorganic ligands.…”

“…Several studies have reported that the two-site nonequilibrium transport model was helpful in describing the transport characteristics of antibiotic pollutants. 12,84 The obtained tting parameters are shown in Table S6. † The mobility results of TC were well simulated by this mathematical model in this work (r 2 > 0.995, Table S6 †).…”

“…Findings of these investigations showed that a variety of environmental factors including divalent metal cations, pH, presence of colloids/nanoparticles, natural organic matter, organic acids, and ionic strength) could affect the mobility of antibiotics in the subsurface environments. 10,[12][13][14][15][16][17] For example, it has been reported that natural organic matter (e.g., humic acid) promoted TC transport due to the adsorption of TC on organic matter, the electrostatic repulsion between quartz sand particles and TC molecules, and the deposition competition between humic acid and TC molecules on porous media in quartz sand column. 18 Moreover, co-existing engineered nanoparticles/naturals colloids (e.g., microplastics, graphene oxide, carbon nanotubes, and soil/clay colloids) may inuence the mobility of antibiotics (e.g., tetracycline, chlortetracycline, and oxytetracycline) in aquifers.…”