Site Of Deposition Research Articles

Wetting-induced soil CO2 emission pulses are driven by interactions among soil temperature, carbon, and nitrogen limitation in the Colorado Desert.

Warming-induced changes in precipitation regimes, coupled with anthropogenically enhanced nitrogen (N) deposition, are likely to increase the prevalence, duration, and magnitude of soil respiration pulses following wetting via interactions among temperature and carbon (C) and N availability. Quantifying the importance of these interactive controls on soil respiration is a key challenge as pulses can be large terrestrial sources of atmospheric carbon dioxide (CO2 ) over comparatively short timescales. Using an automated sensor system, we measured soil CO2 flux dynamics in the Colorado Desert-a system characterized by pronounced transitions from dry-to-wet soil conditions-through a multi-year series of experimental wetting campaigns. Experimental manipulations included combinations of C and N additions across a range of ambient temperatures and across five sites varying in atmospheric N deposition. We found soil CO2 pulses following wetting were highly predictable from peak instantaneous CO2 flux measurements. CO2 pulses consistently increased with temperature, and temperature at time of wetting positively correlated to CO2 pulse magnitude. Experimentally adding N along the N deposition gradient generated contrasting pulse responses: adding N increased CO2 pulses in low N deposition sites, whereas adding N decreased CO2 pulses in high N deposition sites. At a low N deposition site, simultaneous additions of C and N during wetting led to the highest observed soil CO2 fluxes reported globally at 299.5μmol CO2 m-2 s-1 . Our results suggest that soils have the capacity to emit high amounts of CO2 within small timeframes following infrequent wetting, and pulse sizes reflect a non-linear combination of soil resource and temperature interactions. Importantly, the largest soil CO2 emissions occurred when multiple resources were amended simultaneously in historically resource-limited desert soils, pointing to regions experiencing simultaneous effects of desertification and urbanization as key locations in future global C balance.

Reconstructing the geological provenance and long-distance movement of rectangular, fishtail, and croisette copper ingots in Iron Age Zambia and Zimbabwe.

The southern third of Africa is unusually rich in copper ore deposits. These were exploited by precolonial populations to manufacture wound-wire bangles, other forms of jewelry, and large copper ingots that were used as stores of copper or as forms of prestige. Rectangular, fishtail, and croisette ingots dating between the 5th and 20th centuries CE have been found in many locations in the Democratic Republic of the Congo (DRC), Zambia, and Zimbabwe, with isolated finds in Malawi and Mozambique. Molds for casting these ingots have been found mostly in the Central African Copperbelt, but also around the Magondi Belt copper deposits in northern Zimbabwe. For years, scholars have debated whether these ingots were exclusively made in the Copperbelt or if the molds found in Zimbabwe indicate that local copies were produced from Magondi Belt copper ore (Garlake 1970; Bisson 1976). Before the recent application of lead isotopic and chemical methods to provenance copper in central and southern Africa, there was no way to discern between these hypotheses. Rademakers et al. (2019) and Stephens et al. (2020) showed that copper artifacts from southern DRC (mostly from Upemba) and from northwestern Botswana (Tsodilo Hills) match the lead isotope ratios of ores from the Copperbelt. Building upon these previous studies, we present here the first results from a copper provenance project across the southern third of Africa, from the Copperbelt to northern South Africa. We apply lead isotopic analysis (LIA) and chemical analyses to establish the provenance of 29 croisette ingots recovered in Zimbabwe, 2 fishtail and 1 rectangular ingot recovered from sites in Zambia, and an "X" shaped ingot smelted in an experiment in Zambia in the 1970's. Our chemistry and lead isotopic results indicate that 16 of these objects were smelted with copper from the Copperbelt, 16 objects source more specifically to the Kipushi deposit within this geological district, and only one HXR ingot sources to the Magondi Belt in Zimbabwe. Taken together, we clearly illustrate that croisette ingots were traveling significant distances to reach their eventual sites of deposition, and that there was also local production of these objects in Zimbabwe.

Tracing the origin of large respiratory droplets by their deposition characteristics inside the respiratory tract during speech.

Origin of differently sized respiratory droplets is fundamental for clarifying their viral loads and the sequential transmission mechanism of SARS-CoV-2 in indoor environments. Transient talking activities characterized by low (0.2 L/s), medium (0.9 L/s), and high (1.6 L/s) airflow rates of monosyllabic and successive syllabic vocalizations were investigated by computational fluid dynamics (CFD) simulations based on a real human airway model. SST k-ω model was chosen to predict the airflow field, and the discrete phase model (DPM) was used to calculate the trajectories of droplets within the respiratory tract. The results showed that flow field in the respiratory tract during speech is characterized by a significant laryngeal jet, and bronchi, larynx, and pharynx-larynx junction were main deposition sites for droplets released from the lower respiratory tract or around the vocal cords, and among which, over 90% of droplets over 5 µm released from vocal cords deposited at the larynx and pharynx-larynx junction. Generally, droplets' deposition fraction increased with their size, and the maximum size of droplets that were able to escape into external environment decreased with the airflow rate. This threshold size for droplets released from the vocal folds was 10-20 µm, while that for droplets released from the bronchi was 5-20 µm under various airflow rates. Besides, successive syllables pronounced at low airflow rates promoted the escape of small droplets, but do not significantly affect the droplet threshold diameter. This study indicates that droplets larger than 20 µm may entirely originate from the oral cavity, where viral loads are lower; it provides a reference for evaluating the relative importance of large-droplet spray and airborne transmission route of COVID-19 and other respiratory infections.

Does the multi-proxy Eemian record from the Słup site (central Poland) indicate a more humid climate at the beginning of the hornbeam phase?

A new site of Eemian organogenic deposits in S3up (central Poland) has revealed an intermittent record of several phases within this interglacial. Pollen based studies of the core S3-19, drilled at the littoral zone of the palaeolake, indicated the absence of the E2, E3, E6 and an incomplete record of the E4 and E5 zones of the typical pollen succession. Results of other proxies (plant macrofossils, Cladocera, molluscs, NPPs, isotopes) supported the conclusions derived from the pollen diagram regarding the high humidity and lake water level during the E4 (Corylus-Quercus-Tilia) phase and at the beginning of the E5 (Carpinus-Corylus-Alnus) phase, when the fossil lake was most extensive. Thus, the lack of a record of the E3 and E4 RPAZs was associated with water level lowering and a less humid climate. The results stand in agreement with several other Eemian records from central Poland.

Study on the relationship between hydrodynamic conditions and arsenic content in Quaternary sediments.

Groundwater is susceptible to arsenic contamination by sediment with high arsenic content, which is the primary culprit of regional arsenic pollution and poisoning. To explore the influence of the change in hydrodynamic conditions caused by changes in the sedimentary environment over time on arsenic content in sediments during the Quaternary, the hydrodynamic characteristics and arsenic content enrichment of borehole sediments were studied in typical high-arsenic groundwater areas of the Jianghan-Dongting Basin, China. The regional hydrodynamic conditions represented by each borehole location were analyzed, the correlation between the variation in groundwater dynamics characteristics and arsenic content in different hydrodynamic periods was analyzed, and the relationship between arsenic content and grain size distribution was quantitatively investigated using grain size parameter calculation, elemental analysis, and statistical estimates of arsenic content in borehole sediments. We observed that the relationship between arsenic content and hydrodynamic conditions differed between sedimentary periods. Furthermore, arsenic content in the sediments from the borehole at Xinfei Village was significantly and positively correlated with a grain size of 127.0-240.0μm. For the borehole at Wuai Village, arsenic content was significantly and positively correlated with a grain size of 1.38-9.82μm size (at 0.05 level of significance). However, arsenic content was inversely correlated with grain sizes of 110.99-716.87 and 133.75-282.07μm at p values of 0.05 and 0.01, respectively. For the borehole at Fuxing Water Works, arsenic content was significantly and positively correlated with a grain size of 409.6-655.0μm size (at 0.05 level of significance). Arsenic tended to be enriched in transitional and turbidity facies sediments with normal corresponding hydrodynamic strength but poor sorting. Furthermore, continuous and stable sedimentary sequences were conducive to arsenic enrichment. Fine-grain sediments provided abundant potential adsorption sites for high-arsenic sediments, but finer particle size was not correlated with higher arsenic levels.

Remediation Process in Landfill in Arctic Region - A Case of Circular Economy

The Arctic region is a vast and inhospitable environment that presents significant challenges for waste management. Spanning 27 million Sq. km and shared by eight nations, the region has limited infrastructure and only 11% of waste has been treated properly. The high cost of waste removal in the Arctic, due to logistical and technological constraints, makes the challenge of safe waste management even greater insisting on the need for elaborate research in extracting such resources. Concerning those, this study was conducted to fill this gap by investigating the feasibility of extracting secondary resources from two specific sites: an MSW landfill in Dudinka, Russia and an industrial waste deposition site located in the permafrost zone in the Krasnoyarsk region. The research will evaluate the environmental and ecosystem impacts of these landfills and examine various technical and economic approaches for reclaiming resources from them. The findings of this study will provide valuable insights into the viability of extracting secondary resources from waste in the Arctic and inform future waste management strategies in the region. By applying the principles of the circular economy, that identifies that the best approach for addressing the waste management problem in Dudinka is the creation of an eco-industrial park for deep processing and manufacturing of products from secondary resources reducing the environmental impact of waste disposal and promote sustainable resource utilization in the permafrost regions.

Comparison of Atmospheric and Lithospheric Culturable Bacterial Communities from Two Dissimilar Active Volcanic Sites, Surtsey Island and Fimmvörðuháls Mountain in Iceland.

Surface microbes are aerosolized into the atmosphere by wind and events such as dust storms and volcanic eruptions. Before they reach their deposition site, they experience stressful atmospheric conditions which preclude the successful dispersal of a large fraction of cells. In this study, our objectives were to assess and compare the atmospheric and lithospheric bacterial cultivable diversity of two geographically different Icelandic volcanic sites: the island Surtsey and the Fimmvörðuháls mountain, to predict the origin of the culturable microbes from these sites, and to select airborne candidates for further investigation. Using a combination of MALDI Biotyper analysis and partial 16S rRNA gene sequencing, a total of 1162 strains were identified, belonging to 72 species affiliated to 40 genera with potentially 26 new species. The most prevalent phyla identified were Proteobacteria and Actinobacteria. Statistical analysis showed significant differences between atmospheric and lithospheric microbial communities, with distinct communities in Surtsey's air. By combining the air mass back trajectories and the analysis of the closest representative species of our isolates, we concluded that 85% of our isolates came from the surrounding environments and only 15% from long distances. The taxonomic proportions of the isolates were reflected by the site's nature and location.

Laparoscopic embryo transfer in pigs - comparison of different variants and efficiencies of the method.

The aim of the study was to develop a method of laparoscopic embryo transfer in pigs and to compare different variants of this method. Two catheter diameters (1.6 mm and 1.0 mm), the method and site of embryo deposition (oviduct or uterus), the embryo development stage (2 - 4 cell or blastocyst), the method for oviduct or uterus stabilization, the potential for cryopreserved embryo transfer, the developmental potential of the embryos after transfer to the oviduct, patomorphology of the oviduct after transfer and possible clinical complications were taken into consideration. Two studies compared two variants of transfer to the uterus, and five variants of transfer to the fallopian tube. The transfer of embryos by the infundibulum may be of limited use due to handling problems and very low efficiency (pregnancy was not achieved). Very low efficiency was shown after transfer of vitrified embryos. Transfer to the fallopian tube by puncture of the fallopian tube, regardless of the developmental stage of the embryo, is the recommended method of embryo transfer. The histopathological examination of the fallopian tube revealed possible changes within the puncture site. The numerous clinical complications observed did not affect the effectiveness of the method.

Particle Deposition in Large-Scale Human Tracheobronchial Airways Predicted by Single-Path Modelling.

The health effects of particles are directly related to their deposition patterns (deposition site and amount) in human airways. However, estimating the particle trajectory in a large-scale human lung airway model is still a challenge. In this work, a truncated single-path, large-scale human airway model (G3-G10) with a stochastically coupled boundary method were employed to investigate the particle trajectory and the roles of their deposition mechanisms. The deposition patterns of particles with diameters (dp) of 1-10 μm are investigated under various inlet Reynolds numbers (Re = 100-2000). Inertial impaction, gravitational sedimentation, and combined mechanism were considered. With the increasing airway generations, the deposition of smaller particles (dp < 4 μm) increased due to gravitational sedimentation, while that of larger particles decreased due to inertial impaction. The obtained formulas of Stokes number and Re can predict the deposition efficiency due to the combined mechanism in the present model, and the prediction can be used to assess the dose-effect of atmospheric aerosols on the human body. Diseases in deeper generations are mainly attributed to the deposition of smaller particles under lower inhalation rates, while diseases at the proximal generations mainly result from the deposition of larger particles under higher inhalation rates.

Parallel Study of Medodhara Kala and Abdominal Adipose Tissue with Special Reference to Sthoulya (Obesity)

Obesity which is neuroendocrine disorder seems to be common predisposing factor for almost all non-communicable diseases. This neuroendocrine disturbance causes multiple systemic disorders and finally Ayurhasa (reduction in longevity of life) by various means. Ayurveda mentioned eight pathophysiological conditions considered as Nindya (worse conditions). Atisthool (excessive weight) is one of these conditions due to improper Aahara (dietary habits), Vihar (sedentary life style) and changed sleep pattern. Apachita meda (improperly metabolized fat) deposited in Udara (abdomen). Medodharakala according to Ayurveda and abdominal linings bear several similar characteristics related to fat and Medodhatu deposition. Deterioration of functioning of Medodhara kala leads to deposition of Apachita meda leading to Sthoulya. In obesity, abdominal wall, space between organs stores much amount of adipose tissue (site of Meda deposition). So this article reveals with parallel study of Medodhara kala and abdominal adipose tissue to find out similarity.

Single‐Atom‐Mediated Spinel Octahedral Structures for Elevated Performances of Li‐Oxygen Batteries

AbstractLi‐oxygen batteries have attracted much attention due to its ultra‐high theoretical specific capacity, but the discharge product Li2O2is easy to accumulate, leading to low battery stability. Here, we demonstrate a series of high‐efficiency cathode catalysts of Co3O4loaded with single‐atomic metals (M=Ru, Pd, Pt, Au, Ir). The single‐atomic metal could substitute the central Co atom in the octahedral coordination structure and maintain the structural stability; benefiting from the electron promoter effect, rendering more highly active Co3+exposed, providing rich nucleation sites for Li2O2deposition. And the loaded M atoms could separate the active Co3+centers, thereby regulating the dispersion of Li2O2to obtained a sheet‐like morphology, which could facilitate its decomposition in the subsequent charge cycle. Our work found that the single atoms could effectively modulate the active metal oxide with which it is coordinated, thus collectively boosting the catalytic performance.

Single-Atom-Mediated Spinel Octahedral Structures for Elevated Performances of Li-Oxygen Batteries.

Li-oxygen batteries have attracted much attention due to its ultra-high theoretical specific capacity, but the discharge product Li2 O2 is easy to accumulate, leading to low battery stability. Here, we demonstrate a series of high-efficiency cathode catalysts of Co3 O4 loaded with single-atomic metals (M=Ru, Pd, Pt, Au, Ir). The single-atomic metal could substitute the central Co atom in the octahedral coordination structure and maintain the structural stability; benefiting from the electron promoter effect, rendering more highly active Co3+ exposed, providing rich nucleation sites for Li2 O2 deposition. And the loaded M atoms could separate the active Co3+ centers, thereby regulating the dispersion of Li2 O2 to obtained a sheet-like morphology, which could facilitate its decomposition in the subsequent charge cycle. Our work found that the single atoms could effectively modulate the active metal oxide with which it is coordinated, thus collectively boosting the catalytic performance.

Effects of land use on the distribution of soil microplastics in the Lihe River watershed, China

Soil contamination by microplastics (MPs) has gained widespread attention, whose fate may be influenced by land use types. The effects of land use types and the intensity of human activities on the distribution and sources of soil MPs at the watershed scale are unclear. In this study, 62 surface soil sites in representing five land use types (urban, tea garden, dryland, paddy field and woodland) and 8 freshwater sediment sites were investigated in the Lihe River watershed. MPs were detected in all samples, and the average abundance of soil and sediments was 401.85 ± 214.02 and 222.13 ± 54.66 items/kg, respectively. The soil MPs abundance followed the sequence: urban > paddy field > dryland > tea garden > woodland. Soil MP distribution and MP communities were significant different (p < 0.05) among land use types. The similarity of MP community highly correlated with geographic distance, and woodlands and freshwater sediments may be a potential fate for MPs in the Lihe River watershed. Soil clay, pH, and bulk density significantly correlated with MP abundance and fragment shape (p < 0.05). The positive correlation between population density, Total- Point of Interest (POI) and MP diversity indicates the importance of intensity of human activities in exacerbating soil MP pollution (p < 0.001). Plastic waste sources accounted for 65.12%, 58.60%, 48.15% and 25.35% of MPs in urban, tea garden, dryland and paddy field soils, respectively. Differences in the intensity of agricultural activities and cropping patterns were associated with different percentages of mulching film sources in the three types of agricultural soils. This study provides new ideas for the quantitative analysis of soil MP sources in different land use types.

Synergistic enhanced Zinc-ion battery performance achieving by atomic layer deposition of TiO2 on three-dimensional carbon nanotube network decorated Zn anode

Herein, we report a unique synergistic effect between carbon nanotube (CNT) network and atomic layer deposition (ALD) of TiO2, which not only enhances the ability to capture zinc ions but also suppresses Zn dendrite growth, resulting in uniform deposition of zinc ions during repeated cycles. The CNTs with luxuriant three-dimensional skeleton structure can provide plentiful deposition sites on Zn metal anode, which significantly reduces the nucleation overpotential and improves the reaction kinetics. Meanwhile, the TiO2 can repeatedly guide the uniform deposition of Zn owing to the excellent zincophilic. The deposition mechanism of zinc in the modified anode (TiO2CNT@Zn anode) is fully explained by comparing different carbon materials. The TiO2CNT@Zn anode shows a high Zn plating/stripping reversibility with an ultralow nucleation overpotential and achieves an ultralong lifespan over 2000 h with a voltage hysteresis of 22.5 mV compared to bare zinc (BZ) anode (63.7 mV) at a high current density of 5 mA cm−2. Moreover, the TiO2CNT@Zn anode maintains a highly stable Coulombic efficiency of 98.9% for more than 500 h. Moreover, the Zn-MnO2 battery with the TiO2CNT@Zn anode shows remarkably enhanced cycling stability.

Ash‐Free Porous Carbon as the Negative Additive of Lead‐Acid Batteries and Supercapacitors

Herein, a simple method to prepare porous carbon that inhibits hydrogen evolution is used, which has enormous advantages for both capacitors and lead‐acid batteries. The quantitative filter paper spongy porous carbon (SQFPC) is successfully synthesized by the two‐step method. SQFPC displays a porous, spongy structure with a large specific surface area (1847 m2 g−1). In electrochemical tests, SQFPC exhibits high specific capacitance (244 F g−1 at 1 A g−1) and a capacitance retention rate of 72.5% at 40 A g−1. In addition, the capacity of the battery with 0.5 wt% SQFPC is improved by 57.6% at a discharge rate of 0.1C, and the cycle life under the high‐rate partial state of charge is 9.3 times that of the blank battery. The enhanced battery performance is related to the unique structure and surface functional groups of carbon, which speed up ion movement inside the battery and provide active sites for lead deposition.

Implications of Senescent Cell Burden and NRF2 Pathway in Uremic Calcification: A Translational Study.

Increased senescent cell burden and dysregulation of the nuclear factor erythroid 2-related factor 2 (NRF2) pathway have been associated with numerous age-related pathologies; however, their role in promoting vascular calcification (VC) in chronic kidney disease (CKD) has yet to be determined. We investigated whether senescence and NRF2 pathways may serve as drivers of uremia-induced VC using three complementary approaches: a novel model of induced VC in 5/6-nephrectomized rats supplemented with high phosphate and vitamin D; epigastric arteries from CKD patients with established medial calcification; and vascular smooth muscle cells (VSMCs) incubated with uremic serum. Expression of p16Ink4a and p21Cip1, as well as γ-H2A-positive cells, confirmed increased senescent cell burden at the site of calcium deposits in aortic sections in rats, and was similarly observed in calcified epigastric arteries from CKD patients through increased p16Ink4a expression. However, uremic serum-induced VSMC calcification was not accompanied by senescence. Expression of NRF2 and downstream genes, Nqo1 and Sod1, was associated with calcification in uremic rats, while no difference was observed between calcified and non-calcified EAs. Conversely, in vitro uremic serum-driven VC was associated with depleted NRF2 expression. Together, our data strengthen the importance of senescence and NRF2 pathways as potential therapeutic options to combat VC in CKD.

Intensification of the East Asian winter monsoon resulted in greater preservation of terrestrial organic carbon on the inner shelf of the East China Sea since the last 1400 years

The marine shelves of passive margins receive huge amount of terrestrial organic carbon (OC) exported from adjacent terrestrial ecosystems. Long-term sequestration of terrestrial OC into marine sediments plays an important role in the global carbon cycle on a range of timescales. However, our knowledge of factors affecting the fate of terrestrial OC in continental-marginal settings is incomplete, with ongoing debates regarding rates of degradation during transport and burial. In this paper, we employ analyses of total OC and its stable isotope (δ13C), terrestrial biomarkers and mineral surface area in sediment core 39-A obtained from mud-rich regions of the inner shelf of the East China Sea to investigate terrestrial OC burial history over the last 3000 years. Analysis of terrestrial lipid biomarker and terrestrial OC calculated based on a δ13C-binary mixing model shows increasing trends since ∼1400 yr BP, accompanied by a synchronous increase of terrestrial OC preservation rate. By compiling terrestrial OC records from mud-rich regions of the East China Sea inner shelf, we propose that the most reasonable explanation is the intensification of the East Asian Winter Monsoon. This resulted in a strengthening of coastal currents, which accelerated lateral transport speed (thereby shortening oxygen exposure time) of Changjiang (Yangtze River)-derived terrestrial OC towards the deposition site, resulting in greater terrestrial OC preservation. Moreover, we also found delayed responses of terrestrial OC burial to the East Asian Winter Monsoon in the middle and southern part of the Min-Zhe coastal mud region, implying that the transport of terrestrial OC towards this region took place on a centennial-time scale. Our study sheds new light on mechanisms controlling terrestrial OC transport and burial processes in a typical passive marginal sea.

High-Voltage-Enabled Stable Cobalt Species Deposition on MnO2 for Water Oxidation in Acid.

The design and maintenance of highly active sites in anacidic environment is vital and challenging for theoxygen evolution reaction (OER). Inthiswork, it is found that the obtained CoO2 under high applied potential can be stable on MnO2 host in acidic environment, which may act as an effective means to solve the instability of cobalt-based electrocatalyst. The significant improvement of acidic OER activity (6.9 times) and stability (46.4 times) of 90-Co-MnO2 (treated by molten salt with more Co deposition sites) demonstrates the advantages of this approach. In situ Raman and thePourbaix diagram suggest that the enhanced performance derives from the stable presence of CoO2 at the voltage >1.8V versus reversible hydrogen electrode (RHE). However, when the potential is <1.8V, the corresponding other cobalt species is too unstable to facilitate theOER. Density functional theorycalculations reveal that the deposited cobalt oxides can act as active sites, thus effectively reducing the reaction energy barrier of the rate-determining step. This work provides a new perspective for enhancing the stability of cobalt-based electrocatalyst. In the future, the dual consideration of applied potential and stable species of active element in thePourbaix diagram may be a new direction for developing acid-stable electrocatalysts.

Lithiophilic vanadium oxide coated three-dimensional carbon network design towards stable lithium metal anode

The uncontrollable lithium dendrite growth and large volume changes during battery charge/discharge process lead to safety issues and performance degradation problems in lithium metal-based anode. To tackle these issues, an effective solution is to achieve uniform lithium deposition with buffering structure design of the anode. Herein, a high-performance Li host anode composite is developed by coating lithiophilic vanadium oxide onto three-dimensionally structured N-doped CNT rooted on carbon nanotube film (VO2-CNT/CNF). The porous structure of CNT/CNF provides a good buffering effect for the volume change of lithium metal anode during charging and discharging process. At the same time, the N-doped CNTs rooted on CNF fibers provide sufficient lithium nucleation sites for lithium deposition that reduce the regional current density preventing the growth of lithium dendrites. Attributed to these beneficial features, the VO2-CNT/CNF@Li anode exhibits a dendrite-free morphology and excellent cycling performance in lithium-sulfur batteries. The S/C || VO2-CNT/CNF@Li battery also shows good cycling stability at 1 C, and the capacity decay rate per cycle after 500 cycles is less than 0.05%.

Visualization of biochar colloids transport and retention in two-dimensional porous media

Biochar colloids (BCs) have received considerable attention in recent years due to the unique environmental behavior and potential risks. In this work, a real-time visualization system to reveal the transport and retention mechanisms of biochar colliods in two-dimensional (2-D) porous media under the ionic strength (IS), pH and media grain size was developed. The system consists of charge coupled device (CCD) microscope camera and flow cell (connected to a pump and sample collector). The breakthrough curve of flow cell effluent concentration was used to quantitatively analyze the migration behavior of BCs. BCs transport in 2-D porous media was simulated with a simplified Double Monod model. The results show that BCs had a strong migration capacity in 2-D porous media. Electronegativity of BCs and quartz sand increases with the decrease of IS and the increase of pH, and the electrostatic repulsion between them then increases, resulting in the reduction of the adhesion of BCs on the sand surface, which promotes the migration and reduces the retention of BCs in the 2-D porous media. In addition, the reduction of media grain size had an inhibitory effluence on the transport of BCs, and the finer sand could provide more deposition sites for BCs. Meanwhile, the Double Monod model also fitted the transport behavior nicely (R2 > 0.94). The visualization method in this study properly explains the migration behavior of BCs in 2-D porous media, which provides reasonable support for more comprehensive evaluation environmental risk.