Surface Of Soil Particles Research Articles

Study on the Modification of Silty Soil Sites Using Nanosilica and Methylsilicate.

The special particle grading properties of silt lead to the strong water sensitivity and low soil strength of silt sites, many of which are severely damaged and urgently need to be repaired. This article takes the powder soil from a certain burial site area in Xizhu Village, Luoyang as the research object, which is improved by adding nanosilica and potassium methylsilicate. The modified soil is studied through mechanical and waterproof performance tests, and the mechanism of action of the modified material is analyzed through SEM and XRD. The experimental results show that the mechanical properties and waterproof properties of the composite modified soil were improved when the nanosilica content was 2% and the potassium methylsilicate content was 0.5%; the durability of the composite modified soil is improved, making this the optimum ratio. The mechanical properties and water resistance of the silty soil were significantly improved by adding the appropriate amount of nanosilica and potassium methylsilicate. Nanosilica can be evenly dispersed in the soil matrix, absorb a small amount of water to form a gel state, fill the pores in the silt aggregates, and improve soil compactness. In addition, nanosilica aggregates can attach to the surface of the soil particles and extend from the particle surface to the particle edge. By increasing the contact between soil particles and increasing the particle size, the mechanical properties of the modified soil are improved. When potassium methylsilicate solution is added to the soil, it reacts with water and carbon dioxide, decomposes into methylsilicate, and quickly generates a polymethylsiloxane film to cover the surface of soil particles, forming a waterproof film on the surface and thereby improving the waterproof performance of modified soil. Our research results can provide a reference for the restoration and protection of silty and silt-like sites. The next step is to apply the composite modified soil in engineering restoration through field tests in order to study the repairing ability of composite modified soil and its actual protective effects.

Interaction force mechanism for the improvement of reclaimed soil aggregate stability in abandoned homestead by different organic-inorganic soil conditioners

Reasonable application of organic-inorganic soil conditioners can effectively improve the structure and fertility of reclaimed soil in abandoned homestead. Aggregate stability is an important indicator to evaluate soil structure and fertility, and is largely influenced by soil internal forces (van der Waals attractive force, electrostatic repulsive force, hydration repulsive force) and particle surface properties. However, there are few studies on the influence of different soil conditioners on the reclaimed soil internal forces and its relationship with the aggregate stability. Therefore, we selected six different treatments of organic fertilizer (TO), fly ash (TF), maturing agent (TM), maturing agent + organic fertilizer (TMO), fly ash + organic fertilizer (TFO) and control (CK) to conduct a 5-year field experiment to study the effects of reclaimed soil particle interaction forces and surface characteristics on aggregate stability under the treatment of different soil conditioners. The results showed that with the application of soil conditioners, the soil organic matter (SOM), specific surface area (SSA), surface charge (σ0), cation exchange capacity (CEC), aggregate mean weight diameter (MWD) and Hamaker constant increased gradually, while the pH value decreased slightly. In particular, the MWD under the treatments of TFO and TMO increased by 150.3% and 65.6% respectively compared with that under the CK treatment. With the increasing application of soil conditioners, the electrostatic repulsive force and van der Waals attractive force between reclaimed soil particles increased constantly, but the net resultant force between particles decreased and the net attractive force increased continuously, thus improving the aggregate stability. Therefore, there is a significant negative correlation between the net resultant force among reclaimed soil particles and MWD and CEC. In addition, 10−2 mol L-1 is the critical concentration that affects the reclaimed soil internal force, and the organic-inorganic treatments of TFO and TMO can improve the net resultant force better. In a word, the particle interaction forces are important factors affecting the reclaimed soil structural stability, and this study provides a scientific reference for the rational selection of soil conditioners and its interaction force mechanism in the reclaimed soil improvement.

Improving the spatial control of soil biocementation using indigenous microorganisms: Column experiments and reactive transport modeling

Microbially-Induced Calcite Precipitation (MICP), or biocementation, is a biomediated soil improvement process that uses microbial ureolytic activity to enable the precipitation of CaCO3 on soil particle surfaces and contacts. As the technology advances towards practical adoption, approaches that can modulate the spatial uniformity of biocementation and maximize treatment extent will be critical towards reducing implementation costs and impacts. In this study, treatment strategies capable of enriching indigenous ureolytic microorganisms at controlled ureolytic activities and the effects of these techniques on resulting spatial distributions of MICP were explored using centimeter- and meter-scale soil column experiments and reactive transport simulations. In column experiments, differences in treatment solution supplied yeast extract concentrations were shown to reliably control the enrichment of indigenous ureolytic microorganisms and achieve a wide range of ureolytic activities. Reactive transport simulations further demonstrated that reductions in stimulated ureolytic rates could enable more uniform improvement and increases in the extent of improvement with reduced sensitivity to changes in solution injection velocities. A reaction-to-injection duration ratio (RTIDR) parameter was proposed and captured the collective impacts of changes in injection rates and ureolytic reaction rates on reactive transport conditions thereby unifying outcomes from both simulations and experiments. A nonuniformity area (NA) parameter was also introduced to quantitatively characterize differences in biocementation uniformity independent of length scale and CaCO3 magnitudes. Results from this study collectively demonstrate the utility of changes in stimulated ureolytic activities towards controlling the spatial uniformity and extent of biocementation over meter-scale distances.

Shifting the paradigm for phosphorus fertilization in the advent of the fertilizer crisis

AbstractCrop production and food security will be challenged by the availability of phosphate rock and its derived phosphorus (P) fertilizers in the coming decades. Croplands around the world have traditionally received huge amounts of P fertilizers. However, P can quickly become unavailable in soil due to its fast adsorption or fixation on the surface of soil particles. Here, we propose the use of microbially mediated mechanisms of soil‐borne populations to solubilize historically accumulated P over years. We argue that microbially mediated solubilization of P can be enhanced through elemental imbalances that intentionally alter the soil carbon:nitrogen:P ratio, enabling a greater P demand by some soil microbial populations. This strategy may potentially reduce our dependence on conventional and exhausting P fertilizers, but the main caveats are also discussed.

Remediation of atrazine-contaminated soil in a fluidized-bed DBD plasma reactor

In this study, an innovative approach combining dielectric barrier discharge (DBD) plasma and fluidized-bed techniques is proposed and employed to remediate atrazine (ATZ) contaminated soil. Compared with traditional fixed-bed plasma soil remediation system, the fluidized-bed DBD plasma soil remediation system ensures sufficient and uniform contact between the chemically reactive species and the fluidized soil particles, thereby improving the migration and infiltration of reactive species in the soil layer and achieving high-efficiency remediation of contaminated soil. The optimum removal efficiency of 91.2% and energy efficiency of 0.342 mg/kJ were achieved, respectively, after only 6 min fluidized-bed DBD plasma treatment, which were 35.5% and 38.9% higher than those in a fixed-bed DBD plasma system. The primary organic intermediates after fluidized-bed DBD plasma treatment were identified, and the toxicological evaluation of intermediates was performed. Additionally, possible degradation pathways of ATZ in the fluidized-bed DBD plasma reactor were proposed. This system may offer an ideal approach to facilitate mass transfer between chemically reactive species and contaminants on the surface of soil particles, which is expected to achieve efficient, rapid, and continuous treatment of actual contaminated soil.

Raman spectroscopic and microscopic monitoring of on-site and in-situ remediation dynamics in petroleum contaminated soil and groundwater

The mechanistic study of soil and groundwater remediation in petroleum contaminated lands significantly demands rapid qualitative and quantitative identification of petroleum substances. However, most traditional detection methods cannot provide the on-site or in-situ information of petroleum compositions and contents simultaneously even with multi-spot sampling and complex sample preparation. In this work, we developed a strategy for the on-site detection of petroleum compositions and in-situ monitoring of petroleum contents in soil and groundwater using dual-excitation Raman spectroscopy and microscopy. The detection time was 0.5 h for the Extraction-Raman spectroscopy method and one minute for the Fiber-Raman spectroscopy method. The limit of detection was 94 ppm for the soil samples and 0.46 ppm for the groundwater samples. Meanwhile, the petroleum changes at the soil-groundwater interface were successfully observed by Raman microscopy during the in-situ chemical oxidation remediation processes. The results revealed that hydrogen peroxide oxidation released petroleum from the interior to the surface of soil particles and then to groundwater during the remediation process, while persulfate oxidation only degraded petroleum on the soil surface and in groundwater. This Raman spectroscopic and microscopic method can shed light on the petroleum degradation mechanism in contaminated lands, and facilitate the selection of suitable soil and groundwater remediation plans.

Study on surface characteristics of Chang’E-5 fine grained lunar soil

<p indent="0mm">Chang’E-5 lunar soil is the youngest lunar soil sample returned by human beings so far, and the shovel samples record the space weathering history of the lunar surface in sampling area. This study found that on the surface of the fine-grained lunar soil particles of Chang’E-5 are widely distributed typical morphological features, such as microcraters, mineral cleavage surfaces, gasification deposition, and covered glass, which reflect that in the space dominated by meteorites and micrometeorites bombardment, the effects of impact fragmentation, melting sputtering, gasification deposition, etc., have transformed the morphology and characteristics of lunar soil particles during weathering transfomation. The results reveal the transformation mechanism of the extreme environment of the lunar surface on the mineral morphology, thus helping scholars better understand the weathering process in space.

The fetch effect on sand transport above a farmland surface and conditions for saturation

The existing aeolian transport models have been developed for saturated sand flow. For unsaturated sand flow, these models produce larger errors. To mitigate this problem, this paper attempts to clarify the fetch effect on the sand transport rate above a farmland surface so as to improve sand transport model. We first defined the C value in the 1978 Lettau and Lettau model as a sand transport coefficient. For saturated sand flow, the C value equals the saturated sand transport coefficient (i.e., C=Csat=6.7); but for unsaturated flow, the C values would be less than 6.7. We found that C increased with increasing fetch length (L) and shear velocity (u*) using data from a field investigation above a farmland surface. The measured C was far less than Csat even at the maximum fetch length (100 m) and the largest shear velocity (0.809 m s−1) during the sand collection in field observations. Based on the relationships among C, L, and u*, we developed an aeolian transport model that accounted for the shear velocity and fetch length. We confirmed that the essential condition for the sand flow to reach saturation was wind speed is strong enough to transport most of the surface soil particles. Thus, the critical shear velocity at which the sand flow can reach saturation (u*c-sat) is close to the threshold shear velocity for entrainment of the largest soil particles. When u* >u*c-sat, the sand transport saturation fetch length decreased rapidly with increasing wind speed. However, due to the high wind speed requirement, it is difficult for the sand flow to reach saturation, which leads to the farmland surface in an environment dominated by wind erosion under normal wind conditions.

A sorption isotherm model for soil incorporating external and internal surface adsorption, and capillarity

Soil water sorption isotherm is governed by soil–water interactions of adsorption and capillarity, depending on particle surface properties and pore size distribution, respectively. Recent studies have separated soil particle surfaces into two categories in terms of distinct adsorption behaviors, i.e., external and internal surfaces, identifying three independent sorption processes with varying energy levels, namely external adsorption, internal adsorption, and capillarity. Here, an isotherm model is developed to describe water sorption on soils in the full relative humidity ( RH) range by incorporating the three physical processes. The internal and external adsorptions are represented by an augmented-Brunauer–Emmett–Teller (A-BET) equation, and capillarity is described by Kosugi’s model. Two scaling factors are introduced to expand A-BET equation’s application RH range from 0%−40% to 0%−100%—one for the reduction of available adsorption area in restricted pores and another for the disparity between heats of adsorption and liquefaction. Experimental validation demonstrates that the proposed model excellently matches the isotherm data for a wide array of soils in the full RH range. Further, the proposed model performs well in capturing soil water retention data in the full matric potential range, providing a seamless linkage between soil sorption isotherm and water retention behaviors.

Raindrop-impact-induced ejection characteristics of surface particles for soils with a textural gradient

The ejection of surface soil particles caused by raindrops is an important stage of water erosion. Generally, surface soil is typically comprised of more complex structural units (e.g. crumb, block, or platy structures) rather than single granular structures (e.g. aggregate), especially on surface soil influenced by the different arrangement mode between soil particles. Thus, soil aggregate samples as a selected test material cannot properly characterise the particle ejection characteristics of surface soil with more complex structural units during rainfall. Considering this issue, undisturbed soil samples with a textural gradient were collected as test materials for this study and a needle-type raindrop simulator was used to simulate rainfall experiments. Our results demonstrate that, the first 6 min of rainfall is the key period for particle ejection. During this phase of the experiment, the clay-sized and fine-silt-sized particles were preferentially ejected, and the enrichment ratio (ER) of those particles decreased progressively from sandy loam to silty clay loam. With increased rainfall duration, the soils with a low clay content (e.g. sandy loam, silty loam and loam) were found to develop surface crusts more easily compared with clay loam and silty clay loam. Although the formation of soil crust reduced the size-selectivity of the splash-detached particles, the percentage of sand-sized particles in splash-detachment particles showed an increasing trend, while the percentage of clay-sized and fine-silt-sized particles showed a decreasing trend. The finding of this study suggests that identifying changes in the soil surface condition, as determined by soil texture, is the key factor affecting the ejection characteristics of surface soil particles during splash erosion.

Frost heave mitigation of silt clay using nonionic polyacrylamide

Frost heave occurs frequently in high-latitude or high-altitude areas in many parts of the world, and it is a common challenge for geotechnical engineers in road construction. In order to solve the excessive frost heave induced frost damage to geotechnical engineering in cold regions, frost heave susceptible soil from the Tibetan Plateau (the seasonal frozen area) is modified by nonionic polyacrylamide (NPAM) and then used for frost heave testing. Moreover, cohesion test, permeability test, scanning electron microscopy (SEM) test, and Fourier transform infrared spectroscopy (FTIR) analysis are carried out on the NPAM modified soil to gain more insight into the frost heave mitigation mechanism. The impact of NPAM on soil frost heave and its physicochemical mechanism for frost heave mitigation are subsequently investigated. Our results demonstrate that NPAM is physically adsorbed on the surface of soil particles through hydrogen bonding. The increase of NPAM content does not only increase the viscosity of the solution, but it also enhances the aggregation of fine soil particles. In addition, the permeability of the modified soil decreases with increasing NPAM content, thus implying an increase in the water migration resistance. NPAM can be effectively used to reduce the frost heave susceptibility of soil. Our results show that 0.3 wt% of NPAM can significantly convert a strong frost heave soil to a weak frost heave soil. Our results reveal the mechanism of frost heave mitigation using NPAM and provides engineers and researchers with a new physicochemical method for the treatment of frost heave susceptible soil in railway and road construction in cold regions.

Comparison of saturated hydraulic conductivity estimated by surface NMR and empirical equations

This study used eight empirical equations such as Kozeny-Carman (K-C), Terzaghi, Hazen, Slitcher, Kruger, Sauerbrei, NAVFACDM7, and Zamarin to estimate saturated hydraulic conductivity from soil particle size distribution and surface NMR porosity. The estimated empirical hydraulic conductivities were compared with the saturated surface nuclear magnetic resonance (surface NMR) hydraulic conductivity. It was found that most of the empirical equations showed poor correlation with the surface NMR hydraulic conductivity except Kozeny-Carman (KC), Hazen, and Zamarin equations. The value of the coefficient (β) of each equation is modified in such a way as to obtain a linear equation with the unit slope to improve the performance and accuracy of empirical equations. The modified Kozeny-Carman equation showed the maximum correlation R2=0.904, Pearson's r=0.951, and RMSE =6.36 in comparison with other empirical equations. The NAVFACDM7 and the Terzaghi equations showed the highest underestimated hydraulic conductivity data (64%) and overestimated hydraulic conductivity data (38%); however, the Zamarin equation showed the highest overlapped hydraulic conductivity data (44%), respectively, with the 1:1 line.

Resolving seasonal and diel dynamics of non-rainfall water inputs in a Mediterranean ecosystem using lysimeters

Abstract. The input of liquid water to terrestrial ecosystems is composed of rain and non-rainfall water (NRW). The latter comprises dew, fog, and the adsorption of atmospheric vapor on soil particle surfaces. Although NRW inputs can be relevant to support ecosystem functioning in seasonally dry ecosystems, they are understudied, being relatively small, and therefore hard to measure. In this study, we apply a partitioning routine focusing on NRW inputs over 1 year of data from large, high-precision weighing lysimeters at a semi-arid Mediterranean site. NRW inputs occur for at least 3 h on 297 d (81 % of the year), with a mean diel duration of 6 h. They reflect a pronounced seasonality as modulated by environmental conditions (i.e., temperature and net radiation). During the wet season, both dew and fog dominate NRW, while during the dry season it is mostly the soil adsorption of atmospheric water vapor. Although NRW contributes only 7.4 % to the annual water input, NRW is the only water input to the ecosystem during 15 weeks, mainly in the dry season. Benefitting from the comprehensive set of measurements at our experimental site, we show that our findings are in line with (i) independent measurements and (ii) independent model simulations forced with (near-) surface energy and moisture measurements. Furthermore, we discuss the simultaneous occurrence of soil vapor adsorption and negative eddy-covariance-derived latent heat fluxes. This study shows that NRW inputs can be reliably detected through high-resolution weighing lysimeters and a few additional measurements. Their main occurrence during nighttime underlines the necessity to consider ecosystem water fluxes at a high temporal resolution and with 24 h coverage.

Internal erosion in hydrophobic and hydrophilic soils

The water repellency of soil occurs when organic matter coats the soil particle surface; this can either happen naturally due to wildfire and fungal growth or be induced by chemical treatments. The internal stability of water-repellent soils subjected to seepage has not been explored in the literature. In this study, the mechanical responses to internal erosion in three synthetic water-repellent soils, treated by different organic matters, were first investigated using a modified stress-controlled triaxial apparatus. The degree of hydrophobicity of the test soils was assessed through the measurement of apparent water contact angle. In each internal erosion test, the cumulative particle loss, deformation and hydraulic conductivity were evaluated. The water-repellent coatings efficiently suppressed the progression of internal erosion at practical hydraulic gradients because of their smaller fluid–solid adhesion. Continuously increasing the hydraulic gradient would finally result in a breakthrough of internal erosion due to the saturation of the hydrophobic soils under high pore-water pressures. Post-erosion contact angle measurements and scanning electron microscopy images confirmed the durability of the three water-repellent coatings against seepage erosion. The findings of this study confirm the potential of applying hydrophobic soils to mitigate internal erosion under normal hydraulic loading conditions.

Influence of 2‐hydroxypropyltrimethyl ammonium chloride chitosan on sedimentation and volume change behavior of cohesive soil sediments

AbstractThe 2‐hydroxypropyltrimethyl ammonium chloride chitosan (HACC), introducing the functional quaternary ammonium group to the structure of Chitosan, has greatly broadened the application prospect. The influence on natural cohesive soil has rarely been considered. The sedimentation tests for the natural soil in HACC solutions and the HACC‐treated soils in distilled water are considered to analyze the change of sedimentation behaviors in this paper. Moreover, the potential change on the surface of soil particles, the change in particle size distribution, X‐ray diffraction of Ca‐montmorillonite/HACC, and scanning electron microscopy images are investigated to explain the reasons for the results. Results indicate that the surface potential of soil particles achieved reversal, and the particle size had significant agglomeration. The adsorption of HACC results in the rapid sedimentation of the treated soils in water. HACC has a significant influence on setting time and final volume. HACC cannot inhibit the interlayer swelling of Ca‐montmorillonite. The dehydration process can promote the aggregation effect of the treated soils. The specific effects provided an essential train of thought to solve soil problems.

Mineralogy, morphology, and reaction kinetics of ureolytic bio-cementation in the presence of seawater ions and varying soil materials

Microbially-induced calcium carbonate precipitation (MICP) is a bio-cementation process that can improve the engineering properties of granular soils through the precipitation of calcium carbonate (CaCO3) minerals on soil particle surfaces and contacts. The technology has advanced rapidly as an environmentally conscious soil improvement method, however, our understanding of the effect of changes in field-representative environmental conditions on the physical and chemical properties of resulting precipitates has remained limited. An improved understanding of the effect of subsurface geochemical and soil conditions on process reaction kinetics and the morphology and mineralogy of bio-cementation may be critical towards enabling successful field-scale deployment of the technology and improving our understanding of the long-term chemical permanence of bio-cemented soils in different environments. In this study, thirty-five batch experiments were performed to specifically investigate the influence of seawater ions and varying soil materials on the mineralogy, morphology, and reaction kinetics of ureolytic bio-cementation. During experiments, differences in reaction kinetics were quantified to identify conditions inhibiting CaCO3 precipitation and ureolysis. Following experiments, scanning electron microscopy, x-ray diffraction, and chemical composition analyses were employed to quantify differences in mineralogical compositions and material morphology. Ions present in seawater and variations in soil materials were shown to significantly influence ureolytic activity and precipitate mineralogy and morphology, however, calcite remained the predominant CaCO3 polymorph in all experiments with relative percentages exceeding 80% by mass in all precipitates.

Study on Mechanical Properties of Permeable Polymer Treated Loess.

The reinforcement and durability of loess are of great importance for road performance. In this study, a self-designed grouting system and newly permeable polymers were adopted to investigate the mechanical properties and durability of solidified loess (SL), considering different dry densities and water contents. The unconfined compression test and piezocone penetration (CPTU) test were used to examine the mechanical properties. The mechanism of the loess solidified by permeable polymer was analyzed from the micro-level by SEM, MIP, and XRD tests. The test results show that the effect of polymer grouting is obvious, the unconfined compressive strength (UCS) of the SL after grouting is as high as 3.05–5.42 MPa; it is 11.83–20.99 times that of unsolidified loess (UL). The UCS of the SL after grouting is inversely proportional to the dry densities and water contents. After 56 days of immersion, the SL still shows a high compressive strength. The additional erosion of the SL was not caused by the salt solution; the durability is significantly better than that of cement mixing soil. The sensitivity of various factors on the UCS of the SL are service environment > water content > dry density. The SEM tests clearly show that the gel formed by the reaction of the polymer with water on the surface of soil particles makes the bond of soil particles tighter. It can be observed from the MIP test that the cumulative mercury of SL was 0.115 mL/g, which was 33.72% of UL (0.341 mL/g), and the cumulative mercury of SL after immersion in water and salt solutions was 0.183 mL/g and 0.175 mL/g, which was 53.7% and 51.3% of UL (0.341 mL/g), respectively. The XRD results show that there are no other new mineral components produced after grouting and the spacing between crystalline planes decreases, which proves that permeable polymer grouting makes the soil denser and does not erode the soil particles.

Degradation of chloramphenicol in soil with catechin-enhanced ferric iron/persulfate system

Chloramphenicol (CAP) is a broad-spectrum antibiotic that has been commonly used in the world for the past few decades because of its high antibacterial activity. Although CAP has been banned, high concentration is still detected in the soil environment because of its low self-degradation. In the present research, the polluted soil was treated in situ in a sulfate radical (SO4•−) based process. CAP was degraded by persulfate (PS) activated with Fe(III) and catechin (CAT). Fe(II) could be produced efficiently via complexation and reduction through Fe(III) and CAT reaction to enhance the PS activation efficiency. The optimal dosages of PS, CAT and Fe(III) were investigated. The degradation rate of CAP could reach 94.3% after 120 min of reaction. The contribution of free radicals on CAP degradation was also detected, and the results showed that SO4•− and HO• resulted in pollutant removal of 83.8% and 16.2%, respectively. The reaction between CAT and Fe(III) mainly occurred on the surface of soil particles because of the strong adsorption of CAT. However, the oxidation process between radicals and CAP mainly occurred in the liquid phase. Moreover, the biological toxicity of the reaction system and the total organic carbon of organic matter were also significantly reduced.

Water-solid contact electrification causes hydrogen peroxide production from hydroxyl radical recombination in sprayed microdroplets.

Contact electrification between water and a solid surface is crucial for physicochemical processes at water-solid interfaces. However, the nature of the involved processes remains poorly understood, especially in the initial stage of the interface formation. Here we report that H2O2 is spontaneously produced from the hydroxyl groups on the solid surface when contact occurred. The density of hydroxyl groups affects the H2O2 yield. The participation of hydroxyl groups in H2O2 generation is confirmed by mass spectrometric detection of 18O in the product of the reaction between 4-carboxyphenylboronic acid and 18O-labeled H2O2 resulting from 18O2 plasma treatment of the surface. We propose a model for H2O2 generation based on recombination of the hydroxyl radicals produced from the surface hydroxyl groups in the water-solid contact process. Our observations show that the spontaneous generation of H2O2 is universal on the surfaces of soil and atmospheric fine particles in a humid environment.

Degradation of tiamulin by a packed bed dielectric barrier plasma combined with TiO2 catalyst

Recently, a plasma catalyst was employed to efficiently degrade antibiotic residues in the environment. In this study, the plasma generated in a packed bed dielectric barrier reactor combined with TiO2 catalyst is used to degrade the antibiotic tiamulin (TIA) loaded on the surface of simulated soil particles. The effects of applied voltage, composition of the working gas, gas flow rate and presence or absence of catalyst on the degradation effect were studied. It was found that plasma and catalyst can produce a synergistic effect under optimal conditions (applied voltage 25 kV, oxygen ratio 1%, gas flow rate 0.6 l min−1, treatment time 5 min). The degradation efficiency of the plasma combined with catalyst can reach 78.6%, which is 18.4% higher than that of plasma without catalyst. When the applied voltage is 30 kV, the gas flow rate is 1 l min−1, the oxygen ratio is 1% and the plasma combined with TiO2 catalyst treats the sample for 5 min the degradation efficiency of TIA reached 97%. It can be concluded that a higher applied voltage and longer processing times not only lead to more degradation but also result in a lower energy efficiency. Decreasing the oxygen ratio and gas flow rate could improve the degradation efficiency. The relative distribution and identity of the major TIA degradation product generated was determined by high-performance liquid chromatography–mass spectrometry analysis. The mechanism of TIA removal by plasma and TiO2 catalyst was analyzed, and the possible degradation path is discussed.