Evolution of dissolved organic matter during artificial groundwater recharge with effluent from underutilized WWTP and the resulting facilitated transport effect

Transport of Cu2+ in Unsaturated Porous Medium with Humic Acid/Iron Oxide Nanoparticle (Fe3O4) Amendment

“…The FTIR spectrum of HA reveals a broad band at 3255 cm −1 , attributed to O-H and trace N-H stretching [41]. The peak at 1565 cm −1 and 1378 cm −1 are identified as N-H bending vibration and C-N stretching vibrations while peaks around wavelengths 1007 cm −1 and 912 cm −1 correspond to C-H stretching [42]. The band located at 1039 cm −1 in the FTIR spectrum of Figure 2b,c shows the zeta potentials and hydrodynamic diameters of different samples when IS varied from 0 to 100 mM.…”

Transport of Veterinary Antibiotics in Farmland Soil: Effects of Dissolved Organic Matter

“…With increasing the HA concentration from 0 to 80 mg L −1 , the fraction of equilibrium sorption site (f e ) decreased from 0.185 to 0.133, while the kinetic rate constant (α k ) increased from 1.91 to 3.72 d −1 , which suggest a significant expansion of the nonequilibrium sorption sites (1 − f e ) in the presence of DOM. Similarly, competitive sorption of DOM with various other antibiotics such as chlortetracycline, tylosin, sulfamethazine, and nalidixic acid was found to be responsible for the enhanced mobility of the antibiotics observed [92,95]. The fitting results of the antibiotic BTCs with the two sorption site model showed that, upon DOM addition, the mobility of chlortetracycline was greatly enhanced in both the surface and subsurface soils, while increased mobility of tylosin and sulfamethazine was observed only in surface soil columns, which had higher organic matter contents relative to the corresponding subsurface soil columns [95].…”

“…One kinetic site sorption model assumes that the sorption of reactive solute occurs kinetically in a uniform transport domain, and it is usually described using the first-order equation. Thus, the conventional advection−dispersion equation is modified to include a first-order equation that describes the one-site sorption model, as given below [92]:…”

“…In the same way, it can be reduced to one kinetic site sorption model when the kinetic sorption rates on both site fractions are the same, or can be reduced to a chemical equilibrium model when both rates are equally high to be considered instantaneous. These models have been successfully used to describe VA transport with the presence of DOM [92,95,101,102].…”

“…For nalidixic acid transport upon the addition of DOM, it was found that parameter α k increased from 0.00095 to 0.05800 h −1 , and the fitted K d reduced from 39.77 to 7.60 cm 3 g −1 , which revealed facilitated transport and nonlinear kinetic binding of nalidixic acid on the mineral surface [102]. In another study on tetracycline transport, one kinetic sorption site model was used, and decreases in the attachment rate (k att ) (from 1.135 to 0.665 min −1 ) and saturated sorption capacity (S max ) (from 2.990 to 2.617 mg g −1 ) but increases in the detachment rate (k det ) (from 0.001 to 0.010 min −1 ) were observed with the increasing HA concentration [92]. The colloid facilitated transport model could also be used to simulate the BTCs of SAs and manure DOM, as indicated by the normalised root mean square error (NRMSE) ranging from 0.01 to 0.39 [33].…”