Sorption Model Research Articles

Modified GAB model of sorption on banana: spreading pressure and Gibbs free energy

Modified GAB model of sorption on banana: spreading pressure and Gibbs free energy

Effects of Temperature and DC Electric Fields on Perfluorooctanoic Acid Sorption Kinetics to Activated Carbon.

Sorption to activated carbon is a common approach to reducing environmental risks of waterborne perfluorooctanoic acid (PFOA), while effective and flexible approaches to PFOA sorption are needed. Variations in temperature or the use of electrokinetic phenomena (electroosmosis and electromigration) in the presence of external DC electric fields have been shown to alter the contaminant sorption of contaminants. Their role in PFOA sorption, however, remains unclear. Here, we investigated the joint effects of DC electric fields and the temperature on the sorption of PFOA on activated carbon. Temperature-dependent batch and column sorption experiments were performed in the presence and absence of DC fields, and the results were evaluated by using different kinetic sorption models. We found an emerging interplay of DC and temperature on PFOA sorption, which was linked via the liquid viscosity (η) of the electrolyte. For instance, the combined presence of a DC field and low temperature increased the PFOA loading up to 38% in 48 h relative to DC-free controls. We further developed a model that allowed us to predict temperature- and DC field strength-dependent electrokinetic benefits on the drivers of PFOA sorption kinetics (i.e., intraparticle diffusivity and the film mass transfer coefficient). Our insights may give rise to future DC- and temperature-driven applications for PFOA sorption, for instance, in response to fluctuating PFOA concentrations in contaminated water streams.

Machine learning surrogates for surface complexation model of uranium sorption to oxides

The safety assessments of the geological storage of spent nuclear fuel require understanding the underground radionuclide mobility in case of a leakage from multi-barrier canisters. Uranium, the most common radionuclide in non-reprocessed spent nuclear fuels, is immobile in reduced form (U(IV) and highly mobile in an oxidized state (U(VI)). The latter form is considered one of the most dangerous environmental threats in the safety assessments of spent nuclear fuel repositories. The sorption of uranium to mineral surfaces surrounding the repository limits their mobility. We quantify uranium sorption using surface complexation models (SCMs). Unfortunately, numerical SCM solvers often encounter convergence problems due to the complex nature of convoluted equations and correlations between model parameters. This study explored two machine learning surrogates for the 2-pK Triple Layer Model of uranium retention by oxide surfaces if released as U(IV) in the oxidizing conditions: random forest regressor and deep neural networks. Our surrogate models, particularly DNN, accurately reproduce SCM model predictions at a fraction of the computational cost without any convergence issues. The safety assessment of spent fuel repositories, specifically the migration of leaked radioactive waste, will benefit from having ultrafast AI/ML surrogates for the computationally expensive sorption models that can be easily incorporated into larger-scale contaminant migration models. One such model is presented here.

Sulfate affinity controls phosphate sorption and the proto-transformation of schwertmannite

Schwertmannite is a metastable sulfate-rich ferric iron Fe(III) (oxyhydr)oxide and a common mineral in acid mine drainage sites and acid sulfate soils. Schwertmannite is also used as a sorbent in various industrial applications, including phosphate removal in water treatment and environmental remediation. Phosphate sorption to schwertmannite, however, is complex and likely involves ligand exchange for inner- and outer-spherically coordinated sulfate groups, both on the surface and in the tunnel structure of the mineral. Here, we investigated phosphate sorption, concomitant sulfate release and their impact on the structure of schwertmannite as a function of pH and phosphate concentration. Kinetic and equilibrium batch experiments with synthetic schwertmannite were carried out at pH 3, 6, and 8, and the solid-phase was analyzed using a combination of microscopic, spectroscopic, and X-ray diffraction techniques. We found a strong correlation between phosphate sorption and sulfate release, with both following a two-step sorption model. The kinetics of phosphate sorption and sulfate release were faster at higher pH levels. Maximum phosphate sorption was found at pH 6 (1.7 mmol PO43− g−1), which decreased to 1.5 and 1.2 mmol PO43− g−1 at pH 3 and 8, respectively. Fourier transform infrared spectroscopy revealed a shift from inner- to outer-spherical coordination of sulfate with increasing pH. 57Fe-Mössbauer analyses of schwertmannite demonstrated an initial transformation of schwertmannite at neutral to alkaline pH, characterized by a rise in a partially ordered sextet area. This change was interpreted as an increase in crystallinity resulting from the transition from Fe-SO4 to FeO domains. The emerging phase differed from the original schwertmannite, but did not represent a complete change to a new crystalline phase, thus indicating a proto-transformation of schwertmannite. This pH-induced proto-transformation was inhibited in the presence of phosphate. We concluded that the phosphate sorption rate and maximum as well as the proto-transformation of schwertmannite were strongly affected by the mineral's affinity for sulfate. Sorption to schwertmannite should primarily be regarded as a competitive exchange reaction between the sorbing oxyanion and the bound sulfate. As a result, the highest phosphate sorption occurred at circumneutral pH, in stark contrast to non-sulfate-containing Fe(III) (oxyhydr)oxides, where phosphate sorption is highest at acidic pH. Our findings are important for a fundamental understanding of the sorption properties of schwertmannite in phosphate-rich environments as they point towards the central role of sulfate coordination for phosphate immobilization.

Investigating contaminant leakage in sawtooth-configured non-pumping reactive wells: A sandbox test approach

Non-pumping reactive wells (NPRWs) are passive remediation technologies for contaminated groundwater that use various configurations of wells filled with reactive materials. This study evaluated the performance of sawtooth array NPRWs, which is a configuration that considers minimum well spacing for ground stability, and investigated contaminant leakage through them. A sandbox was constructed to observe point-by-point differences in cadmium (Cd) concentrations through the NPRWs. Groundwater flow and solute transport were simulated numerically to determine contaminant leakage and decontamination performance. Finally, the performance of the saw tooth-configured NPRWs was evaluated considering removal efficiency and longevity. The sandbox test results showed that the Cd concentrations exhibited very similar upgradient trends. Significant downgradient decontamination of Cd by the reactive materials was confirmed. Specifically, the Cd concentrations exhibited highly dispersed or wide spatial variations at each point, indicating contaminant leakage. The Langmuir sorption model, which uses the concept of maximum sorption capacity, was the most suitable for explaining the occurrence of contaminant leakage. The removal efficiency decreased over time because of the leakage of pollutants and the longevity was determined to be 890 h. The investigation of contaminant leakage provides a method for quantitatively assessing the performance of NPRWs facility and can be valuable in the design phase for optimizing NPRWs configurations, including suggesting safety factors to prevent leaks.

Longevity prediction of reactive media in permeable reactive barriers considering the contamination level and groundwater velocity at the planning site, with a focus on cadmium removal by zeolite

Zeolite is a versatile and effective reactive material used in permeable reactive barriers (PRBs) for remediating groundwater contaminated with heavy metals. In this study, we evaluated the influence of subsurface environmental conditions, namely contamination level (C0) and groundwater velocity (v), on predicting the longevity of zeolite for cadmium (Cd) removal. Batch experiments were performed to investigate the effect of C0 on Cd removal, and column experiments were performed to examine how Cd transportation through zeolite varies at different C0 and v. Breakthrough curves (BTCs) were analyzed with an advection-dispersion equation (ADE) coupled with nonequilibrium sorption rate models. The reaction parameters indicating the performance metrics of zeolite were determined using an iterative fitting approach—retardation factor (R), partitioning coefficient (β), and mass transfer coefficient (ω). R exhibited dependence on C0, but was unrelated to v; its rapid increase at lower C0 was explained by Langmuir sorption isotherms. β and ω, integral to sorption dynamics and mass transfer, respectively, showcased functional relationships with v. β decreased gradually as v increased, described by the nonequilibrium sorption model, whereas ω increased steadily with v, guided by the Monod function. Using the relationship of these parameters, the fate and transport of Cd within zeolite was simulated under various subsurface environmental conditions to construct the longevity prediction function. Thus, this study introduces a method for predicting the longevity of reactive materials, which can be valuable for designing PRBs with high longevity in the future.

Water activity and glass transition effect on the physical properties and bioactive compounds of persimmon peel powder

SummaryPersimmon peel is an agro‐industrial by‐product that could be valorised as a potential powdered functional ingredient. However, powdered products exhibit quality and stability problems associated with the water activity and the glass transition. In this work, hot‐air drying was used to produce a persimmon peel powder, which was conditioned at 20 °C at different relative humidity (11.3%–75.5%). The changes in physical properties (water sorption, glass transition, mechanical properties), structure (light microscopy) and bioactive compounds (soluble tannin content, total carotenoid content) were evaluated. By combining the GAB sorption model and the Gordon and Taylor equation, the critical values of water activity (aw = 0.211) and water content (0.029 g water g−1 product), related to the glass transition, were obtained. These values were critical for the production of a free‐flowing powder rich in bioactive compounds and high antioxidant capacity.

Permeability Modeling of Pore Shapes, Compaction, Sorption, and Molecular Diffusivity in Unconventional Reservoirs

Summary Shale and ultratight gas reservoirs are multiscale, containing organic matter (OM) and inorganic minerals in multiple pore compartments of different pore shapes and scales. Selecting a suitable model to describe the multiscale transport mechanisms requires a minimum understanding of the inherent pore shape, OM content, typical pore size, and inherent flow regime. Interestingly, during gas production and associated pressure depletion, some mechanisms, such as pore compressibility, pore diffusion, and diffusion of sorbed gas molecules, become significant at lower pressure. In this study, multiscale and multiphysics permeability models are introduced that couple the effects of poroelasticity (especially in slit-shaped pores with <1.0 aspect ratio) and sorbed gas diffusion, Fick diffusion, transition diffusion, or Knudsen diffusion, depending on the pore structural properties at multiscale for shale and ultratight gas applications. Shale here refers to organic-rich low-permeability rock with >1–2 wt% OM, while ultratight gas has negligible organic content with <1.0 wt%. These experimentally and computationally validated models could be combined with Gaussian pressure transient solutions to effectively understand the uncertainty in multiphysics gas permeability in addition to the hydraulic and natural fracture parameters for large-scale flow simulation of hydraulically fractured unconventional reservoirs.

Radium sorption on crystalline rock; spatial distribution and sorption modeling study

Spent nuclear fuel from the Finnish and Swedish nuclear power plants will be permanently disposed of in deep geological disposal facilities located on the coast of the Baltic Sea. As a part of the disposal's safety case, the migration properties of the safety-relevant spent nuclear fuel-borne radionuclides, such as the radionuclide progeny of the waste component 238U, 226Ra, need to be assessed in the lithosphere surround the facility. To this end, the sorption of Ra on disposal-relevant rock and groundwater types was studied in batch sorption experiments in a wide Ra and Ba concentration isotherm (2.6 × 10−9 M to 1 × 10−3 M). The experimental results of the batch sorption experiments were further interpreted using a PHREEQC geochemical model with ion exchange and surface complexation reactions considered. Additionally, the sorption of Ra was studied with thin section sorption studies where autoradiography analysis was combined with mineralogical data obtained in SEM/EDX to establish spatial distribution and mineral specific sorption of Ra on the studied rocks. In the study, it was observed that Ra sorbs well on all tested rock types and water conditions of low ionic competition, regardless of the rock type's projected sorption affinity based on its highly sorbing mica mineral content. In conditions of high ionic competition, Ra tends to stay in the sorption solution, facilitating migration in the disposal context. The obtained experimental and modeled Ra sorption data will be used in the safety case calculations and modeling of the Finnish and Swedish spent nuclear fuel disposal.

Hydrophobic and hygroscopic properties of cellulose treated with silicone agents

The effects of various cellulose treatments on the hydrophobic properties and sorption behavior with respect to liquid water uptake and water vapor sorption were examined within the study. Different hydrophobic agents based on silicon compounds were applied to improve the properties of cellulose-based sheets. The 1H,1H,2H,2H perfluorooctyltriethoxysilane treatment increased hydrophobicity significantly, while N-octyltriethoxysilane and inorganic sodium silicate solution treatments only slightly affected the properties. Silicone-cellulose interaction varied, influencing the fiber saturation and moisture content of the material. The swelling differences between untreated and treated cellulose and, consequently, the uncovering of new active sorption sites during a swelling process and the increase in the content of bound water were confirmed by the T2 relaxation times analysis. The GDW sorption model estimated maximum water content but lacked activation dynamics. The blocking phenomenon of active sorption sites together with silicone improved hydrophobicity had different mechanisms for applied agents. The 1H,1H,2H,2H perfluorooctyltriethoxysilane additionally cross-linked silane structure and restricted cellulose swelling.

A Microporous Poly(Arylene Ether) Platform for Membrane‐Based Gas Separation**

AbstractMembrane‐based gas separations are crucial for an energy‐efficient future. However, it is difficult to develop membrane materials that are high‐performing, scalable, and processable. Microporous organic polymers (MOPs) combine benefits for gas sieving and solution processability. Herein, we report membrane performance for a new family of microporous poly(arylene ether)s (PAEs) synthesized via Pd‐catalyzed C−O coupling reactions. The scaffold of these microporous polymers consists of rigid three‐dimensional triptycene and stereocontorted spirobifluorene, endowing these polymers with micropore dimensions attractive for gas separations. This robust PAE synthesis method allows for the facile incorporation of functionalities and branched linkers for control of permeation and mechanical properties. A solution‐processable branched polymer was formed into a submicron film and characterized for permeance and selectivity, revealing lab data that rivals property sets of commercially available membranes already optimized for much thinner configurations. Moreover, the branching motif endows these materials with outstanding plasticization resistance, and their microporous structure and stability enables benefits from competitive sorption, increasing CO2/CH4 and (H2S+CO2)/CH4 selectivity in mixture tests as predicted by the dual‐mode sorption model. The structural tunability, stability, and ease‐of‐processing suggest that this new platform of microporous polymers provides generalizable design strategies to form MOPs at scale for demanding gas separations in industry.

Insights into mechanism and modelling of dynamic moisture sorption in dual-porous insulation materials with micro- and nano-scale pores

HypothesisUnderstanding moisture sorption in porous insulation materials is challenging due to the influence of multiscale pore structures on phase behavior and transport properties. Dynamic moisture sorption in dual-porous materials is likely co-determined by interior micro- and nano-scale pores, and an accurate physical model for predicting moisture evolution can be developed by clarifying the sorption mechanisms. ExperimentsMoisture behavior during the dynamic sorption of dual-porous insulation material is measured by low-field nuclear magnetic resonance (NMR) experiments. The contributions of micro- and nano-scale pores to the adsorbed moisture are differentiated using NMR relaxometry, and the evolution of moisture morphology is quantitatively analyzed. FindingsAnalysis of T2 evolution reveals that the moisture in nano-scale pores alters from adsorption layers to liquid with increasing relative humidity (RH), while minimal sorption occurs in micro-scale pores. Moisture is mainly transferred as vapor molecules at low RH levels, with the dynamic sorption enhanced by molecular diffusion in micro-scale pores. Capillary flow in nano-scale pores dominates moisture transport when RH rises above a threshold, leading to a significant increase in apparent moisture diffusivity. According to the elucidated mechanism, a physical model is further developed to predict moisture sorption inside dual-porous insulation materials, and it may serve as a basis for evaluating and optimizing the performance of dual-porous systems in different environments.

A Microporous Poly(Arylene Ether) Platform for Membrane-Based Gas Separation.

Membrane-based gas separations are crucial for an energy-efficient future. However, it is difficult to develop membrane materials that are high-performing, scalable, and processable. Microporous organic polymers (MOPs) combine benefits for gas sieving and solution processability. Herein, we report membrane performance for a new family of microporous poly(arylene ether)s (PAEs) synthesized via Pd-catalyzed C-O coupling reactions. The scaffold of these microporous polymers consists of rigid three-dimensional triptycene and stereocontorted spirobifluorene, endowing these polymers with micropore dimensions attractive for gas separations. This robust PAE synthesis method allows for the facile incorporation of functionalities and branched linkers for control of permeation and mechanical properties. A solution-processable branched polymer was formed into a submicron film and characterized for permeance and selectivity, revealing lab data that rivals property sets of commercially available membranes already optimized for much thinner configurations. Moreover, the branching motif endows these materials with outstanding plasticization resistance, and their microporous structure and stability enables benefits from competitive sorption, increasing CO2 /CH4 and (H2 S+CO2 )/CH4 selectivity in mixture tests as predicted by the dual-mode sorption model. The structural tunability, stability, and ease-of-processing suggest that this new platform of microporous polymers provides generalizable design strategies to form MOPs at scale for demanding gas separations in industry.

Hydroxypropyl sulfonated starch and Asperlligus oryzae biomass for cationic dye adsorption: characterization, mechanism, sorption modelling

AbstractIn this work, hydroxypropyl starch sulfate (HPSS) and Aspergillus oryzae (Asp. oryzae) were successfully synthesized and investigated for aqueous methylene blue (MB) adsorption. The as-prepared adsorbents were also characterized extensively using FTIR, XRD, SEM, EDX, and BET surface area analyses to elucidate their functional, textural, and morphological properties. Also, the effects of initial dye concentration, contact time, and pH on the adsorption performance of both adsorbents were systematically investigated. Due to the significant surface area differences, the HPSS recorded a higher maximum adsorption capacity (qmax) of 52.41 mg/g at 20 mg/L initial concentration, 60 min, and pH 8.0, while the Asp. oryzae recorded a qmax of 37.26 mg/g at 20 mg/L initial concentration, 60 min, and pH 9.0. Specifically, the –SO3 groups on the HPSS shared some electrostatic affinity with the MB dye cationic center (N+ backbone), while a hydrogen bond is formed between the hydroxyl groups of the starch and N+ backbone of the MB dye. Also, the nitrogen- and oxygen-containing groups on the Asp. oryzae provided active sites for the binding of MB species. Also, the XRD spectra of the loaded HPSS showed a decrease in the sharp crystalline peaks, while no structural changes were observed in the case of loaded Asp. oryzae. Therefore, the effectiveness of the HPSS and Asp. oryzae for adsorbing MB was established in the study.

Effect of Hydrothermal Aging on Damping Properties in Sisal Mat-Reinforced Polyester Composites.

Hydrothermal aging is a matter of considerable concern for natural fiber-reinforced polymers; it can alter dimensional stability and induce microcracks and macro strain on the composite structure. This study applied a sorption kinetic model and examined the effects of water on the damping factor of sisal mat-reinforced polyester composites. The experimental data were fitted well using a Boltzmann sigmoid function, suggesting a promising first step toward kinetic water sorption modeling. Additionally, a damping test was carried out using the impulse excitation technique, highlighting the composite material's dynamic response under varying water absorption conditions. The result showed that damping exhibited sensitivity to water absorption, increasing significantly during the first 24 h of immersion in water, then remained steady over time, inferring a critical time interval. An empirical model proved satisfactory with the correlation coefficient for sorption rates and damping of sisal mat polymeric composites.

Modeling sorption of environmental organic chemicals from water to soils

Reliable estimation of chemical sorption from water to solid phases is an essential prerequisite for reasonable assessments of chemical hazards and risks. However, current fate and exposure models mostly rely on algorithms that lack the capability to quantify chemical sorption resulting from interactions with multiple soil constituents, including amorphous organic matter, carbonaceous organic matter, and mineral matter. Here, we introduce a novel, generic approach that explicitly combines the gravimetric composition of various solid constituents and poly-parameter linear free energy relationships to calculate the solid-water sorption coefficient (Kd) for non-ionizable or predominantly neutral organic chemicals with diverse properties in a neutral environment. Our approach demonstrates an overall statistical uncertainty of approximately 0.9 log units associated with predictions for different types of soil. By applying this approach to estimate the sorption of 70 diverse chemicals from water to two types of soils, we uncover that different chemicals predominantly exhibit sorption onto different soil constituents. Moreover, we provide mechanistic insights into the limitation of relying solely on organic carbon normalized sorption coefficient (KOC) in chemical hazard assessment, as the measured KOC can vary significantly across different soil types, and therefore, a universal cut-off threshold may not be appropriate. This research highlights the importance of considering chemical properties and multiple solid constituents in sorption modeling and offers a valuable theoretical approach for improved chemical hazard and exposure assessments.

Kinetic and Equilibrium Modelling of Lead, Zinc and Copper Ions Sorption from Aqueous Solution Using Charcoal Fines

The potential of chemically modified charcoal fines UCF (unmodified charcoal fine) and MCF (modified charcoal fines) as low cost adsorbents for the removal of Pb2+, Cu2+ and Zn2+ ions from aqueous solution was studied. MCF was prepared by chemical modification of UCF with HNO3 and KOH followed by pyrolysis. The factors influenced the effectiveness of biosorption process were pH, contact time, initial metal concentration, temperature and adsorbent dosage. FT–IR spectra confirmed the existence and interaction of the adsorbents with the effluent pollutants. MCF exhibited optimum pH, temperature, contact time, initial metal ion concentration and biosorbent dosage values of 5, 35 0C, 90 minutes, 15 mg/L and 2 g, respectively. UCF exhibited optimum pH, temperature, contact time, initial metal ion concentration and biosorbent dosage values of 6, 35 0C, 100 minutes, 20 mg/L and 2.5 g, respectively. The adsorption isotherm modelling using both adsorbents showed that the equilibrium data conformed more to Langmuir than the Freundlich model. Kinetic studies showed that the adsorption processes followed a pseudo-second order kinetic model. Thermodynamic studies confirmed the spontaneity and feasibility of the adsorption process. The results showed that both adsorbent have the potential to be applied as alternative low cost biosorbent.

Obtaining an organosorbent based on Apis Mellifera chitosan and bentonite for cleaning textile wastewater from dyes and metals

This article presents the results of studying the sorption of Cu2+ ions in artificial solutions to ionite obtained on the basis of the PPD brand of Navbakhor bentonite at temperatures of 303, 313 and 323 K, the duration of sorption up to the equilibrium state (between 1-24 hours) and at different concentrations. The kinetics of the processes were studied, Langmuir and Freundlich isotherm models were used to express the adsorption mechanism in the equilibrium state. Based on the obtained results, it was found that the value of isotherm parameters R2 (0,9973) was consistent in all isotherm models. According to the Langmuir isotherm model, 𝑞𝑚𝑎𝑥= 212,7 mg/g, and n=0,2456 according to the Freundlich isotherm model. This indicates the sorption of Cu2+ ions to bentonite-based ionite. Based on scientific research, pseudo-first and pseudo-second order kinetic models of sorption of metal ions to ionite were also studied. It was determined that the obtained kinetic parameters of the process obey the pseudo-second-order model and the sorption of Cu2+ ions to the obtained ionite.

Examining the Water-Polymer Interactions in Non-Isocyanate Polyurethane/Polyhedral Oligomeric Silsesquioxane Hybrid Hydrogels.

Non-isocyanate polyurethane (NIPU) networks physically modified with octa(3-hydroxy-3-methylbutyldimethylsiloxy)POSS (8OHPOSS, 0-10 wt%) were conditioned in environments of different relative humidities (up to 97%) to study water-polymer interactions. The equilibrium sorption isotherms are of Brunauer type III in a water activity range of 0-0.97 and are discussed in terms of the Guggenheim (GAB) sorption model. The study shows that the introduction of 8OHPOSS, even in a large amount (10 wt%), does not hinder the water affinity of the NIPU network despite the hydrophobic nature of POSS; this is attributable to the homogenous dispersion of POSS in the polymer matrix. The shift in the urethane-derived carbonyl bands toward lower wavenumbers with a simultaneous shift in the urethane N-H bending bands toward higher wavenumbers exposes the breakage of polymer-polymer hydrogen bonds upon water uptake due to the formation of stronger water-polymer hydrogen bonds. Upon water absorption, a notable decrease in the glass transition temperature (Tg) is observed for all studied materials. The progressive reduction in Tg with water uptake is driven by plasticization and slaving mechanisms. POSS moieties are thought to impact slaving indirectly by slightly affecting water uptake at very high hydration levels.

Prediction of the mobility and persistence of eight antibiotics based on soil characteristics

Antibiotics are widely used in intensive animal husbandry in the Netherlands and are subsequently emitted to soil via manure. To predict degradation and mobility in soil, generic sorption models have been derived. However, most of the coefficients used in generic models are based on a limited range of soils and have not been validated for agricultural soils in the Netherlands. To improve model predictions and assess to what extent differences among soils affect sorption and degradation, an experimental study has been performed. Using a recently developed experimental approach, both the degradation (DT50) and mobility (Kd) of eight selected commonly used antibiotics were determined in 29 typical Dutch agricultural soils. Median DT50 values range from 5.3 days for Sulfadiazine to 120 days for Trimethoprim but are affected by soil type. The ratio of the lowest and highest DT50 for a given antibiotic among soils can be as large as 151, for Tylosin. Measured values of the logKd also range from 0.19 for Sulfadiazine to more than 2 for Doxycycline, Flumequine, Trimethoprim, Tylosin and Enrofloxacine. The impact of soil on Kd is large, especially for more mobile antibiotics such as Sulfadoxine and Sulfadiazine. Both the range in DT50 and Kd can be predicted reasonably well using a Freundlich type regression model that accounts for the variation in soil type and sampling depth. Organic matter, iron oxides, pH and clay content appear to be the main constituents and explain between 29 % (Trimethoprim) and 77 % of the variation in DT50 and between 64 % (Lincomycin) and 87 % (Sulfadoxine and Sulfadiazine) of the variation of Kd. The effect of depth on DT50 and Kd is however limited. The information thus obtained in combination with local data on soil type can be used to more accurately predict the potential risk of relevant antibiotics in soil and transport to ground- and nearby surface waters.