Abstract Breakthrough curves of water contaminants are usually analyzed using simple fixed bed models such as the Bohart-Adams, Thomas, and Yoon-Nelson equations, which by design symmetric. Because breakthrough data often follow an asymmetric pattern, use that do not account for asymmetry could lead to poor fits, consequently resulting in erroneous estimates exhaustion times. To address this is...

Antibiotics, such as sulfadiazine, reach agricultural soils directly through manure of grazing livestock or indirectly through the spreading of manure or sewage sludge on the field. Knowledge about the fate of antibiotics in soils is crucial for assessing the environmental risk of these compounds, including possible transport to the groundwater. Transport of (14)C-labelled sulfadiazine was inve...

solute transport processes are affected by soil pore water velocity distribution. pore size distribution, which can be used to infer pore water velocity distribution, can be estimated from a soil water retention curve (n). in this study, a solute breakthrough curve was simulated using soil hydraulic parameters in four different soils. to evaluate the proposed model, predictions were compared to...

Chemical and biological transformations can significantly affect contaminant transport in the subsurface. To better understand such transformation reactions, an equilibrium-nonequilibrium sorption transport model, HYDRUS-1D, was modified by including inverse solutions for multiple breakthrough curves resulting from the transport of solutes undergoing sequential transformations. The inverse solu...

fertilizer plant waste carbon slurry has been investigated after some processing as an adsorbent for the removal of dyes and phenols using columns. the results show that the carbonaceous adsorbent prepared from carbon slurry being porous and having appreciable surface area (380 m2/g) can remove dyes both cationic (meldola blue, methylene blue, chrysoidine g, crystal violet) as well as anionic (...

the adsorption of lead (11) and copper (11) in a fixed bed column using activated carbonprepared from nipa palm nut was investigated. thomas model and yoon and nelson kinetic models were used to analyze the column performance. the rate constant for thomas model increased with increase in flow rate and initial ion concentration but remained constant at varying bed height. adsorption capacity for...

The transport and fate of many contaminants in subsurface systems can be influenced by several coupled processes, such as nonlinear, rate-limited sorption and biodegradation. We investigated the transport in soil of a model organic compound, 2,4-dichlorophenoxyacetic acid (2,4-D), influenced by nonlinear, rate-limited sorption and biodegradation. Miscible displacement and batch sorption experim...

Colloid attachment is an important retention mechanism. It is influenced by colloid size, pore size, and flow rate, among other factors. In this work, we studied colloid attachment experimentally under various flow rates, as well as colloid release in response to a rapid change of flow rate. Colloid transport experiments under saturated conditions and with different flow rates were conducted in...

We use Lattice Boltzmann models to simulate solute transport in porous media traversed by larger conduits and fit the resulting solute breakthrough curves with macroscopic Continuous Time Random Walk (CTRW) models. In this paper, the porous media are simulated using a real-numbered coefficient that partially damps the inertial components of the flow and, when the damping is large enough, leads ...

Cr (III) removal from aqueous solutions by sorption in a fixed bed column filled with alizarin S impregnated hemp fibers has been studied. The effect of the initial metal ion concentration on the Cr (III) sorption process was investigated and the experimental breakthrough curves were obtained. The breakthrough time and saturation time decreased from 110 min to 80 min and from 300 min to 160 min...