scholarly journals Mobilisation of Al, Fe, and DOM from topsoil during simulated early Podzol development and subsequent DOM adsorption on model minerals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Agnes Krettek ◽  
Thilo Rennert
Keyword(s):  
Organic Matter ◽  
Acetic Acid ◽  
Dissolved Organic Matter ◽  
Flow Velocity ◽  
Heavy Rain ◽  
Oxide Phase ◽  
Batch Experiments ◽  
Important Species ◽  
Velocity Characteristic ◽  
Soil Percolation

AbstractPodzols are characterised by mobilisation of metals, particularly Al and Fe, and dissolved organic matter (DOM) in topsoil horizons, and by immobilisation in subsoil horizons. We mimicked element mobilisation during early podzolisation by irrigating the AE horizon of a Dystric Arenosol with acetic acid at different flow velocities and applying flow interruptions to study rate-limited release in experiments with soil cylinders. We used eluates in batch experiments with goethite and Al-saturated montmorillonite to investigate DOM reactivity towards minerals. Both the flow velocity and flow interruptions affected element release, pointing to chemical non-equilibrium of release and to particles, containing Fe and OM mobilised at larger flow velocity, characteristic of heavy rain or snowmelt. Based on chemical extractions, the source of mobilised Al and Fe, the vast majority of which was complexed by DOM, was no oxide phase, but rather organic. Rate limitation also affected the composition of DOM released. Carboxyl and phenolic species were the most important species adsorbed by both minerals. However, DOM composition affected the extent of DOM adsorption on goethite more distinctly than that on montmorillonite. Our findings evidence that the intensity of soil percolation affects quantitative and qualitative element release during early podzolisation and adsorptive DOM retention in subsoil horizons.

Production and transformation of volatile fatty acids from sludge subjected to hydrothermal treatment

2001 ◽  
Vol 44 (10) ◽  
pp. 129-135 ◽  
Author(s):  
A. Shanableh ◽  
S. Jones
Keyword(s):  
Fatty Acids ◽  
Organic Matter ◽  
Acetic Acid ◽  
Dissolved Organic Matter ◽  
Hydrothermal Treatment ◽  
Propionic Acid ◽  
Volatile Fatty Acids ◽  
Cod Removal ◽  
The Other ◽  
Maximum Accumulation

The production of useful organic matter from sludge expands the potential for utilizing the product as a resource. This paper is focused on the accumulation and removal of volatile fatty acids (VFAs) produced from primary, secondary and a mixture of both sludges using hydrothermal treatment with and without the use of oxidants. The results confirmed that the maximum accumulation of VFAs was achieved at moderate hydrothermal treatment temperatures below 200°C, and was dependent on the composition of sludge and the amount of oxidant used for treatment. The maximum accumulation reached 0.26-0.36 mg VFAs as COD per mg VS from the three sludge types. Acetic acid dominated the VFAs and was followed by propionic acid, with the other VFAs accounting for less than 5% of the total VFAs. As hydrothermal treatment progressed in terms of COD removal, the contribution of acetic acid to the total VFAs increased while the contributions of the other VFAs decreased. The VFAs constituted a major component of the accumulated dissolved organic matter, which reached a maximum of 0.5-0.7 mg soluble COD per mg VS from the three sludge types.

scholarly journals Transport of Particulate Organic Matter and Dissolved Organic Matter from Land to Ocean in Hokkaido, Japan

2015 ◽  
Vol 63 (1) ◽  
pp. 47-51
Author(s):  
M Jahangir Alam ◽  
S Nagao ◽  
M Emran Quayum
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Matter ◽  
Particulate Organic Matter ◽  
Water Discharge ◽  
Heavy Rain ◽  
Small Rivers ◽  
Snow Melting ◽  
Variation Range ◽  
Rain Fall

Both ?14C, ?13C for the particulate organic matter (POM) and 3-Dimensional Excitation and Emission Matrix spectroscopy (3D-EEM) for the dissolved organic matter (DOM) were used to study transport behavior from land to ocean in Hokkaido, Japan. The ?14C values of the Tokachi POC (particulate organic carbon) show similar variations to Ishikari. However, the variation range of the Tokachi of ?14C is smaller than that of the Ishikari POC. ?13C values for the Ishikari showed larger variation range than those of the Tokachi. The POC during spring snow-melting for the Ishikari and in autumn during heavy rain fall for the Tokachi were distinctive in the correlations of POC, ?14C, and ?13C.There were two different pathways in the correlations of POC content, ?14C, and water discharge for both river systems. The significant pathway during snow-melting found in the Ishikari and at autumn during heavy rain fall for the Tokachi. The Tokachi and the Ishikari River showed similar variations patterns of dissolved organic carbon (DOC) concentrations and relative fluorescence intensity (RFI). The run-off point of DOC and FA-like materials is similar to POC. Therefore, characteristics and export of POC and DOC may be controlled by water discharge in small rivers in sub-arctic zone. The both rivers showed averaged POC flux from 1.43~1.51 ¥ 1010 g/yr, DOC flux of 0.98~2.32 ¥ 1010 g/yr, and fulvic-like materials-carbon (FAC) flux of 0.70~1.22 ¥ 1010 g/yr. The percentages of POC, DOC, and FAC flux in two rivers during snow-melting and heavy rainfall were 78~95% and 25~ 42 %, respectively. The watersheds of the Ishikari and Tokachi are important in transport of POC from land to ocean, especially during snow-melting and heavy rain event. DOI: http://dx.doi.org/10.3329/dujs.v63i1.21768 Dhaka Univ. J. Sci. 63(1): 47-51, 2015 (January)

scholarly journals Influence of sulfide, chloride and dissolved organic matter on mercury adsorption by activated carbon in aqueous system

2020 ◽  
Vol 30 (1) ◽  
Author(s):  
Chi Chen ◽  
Yu Ting ◽  
Boon-Lek Ch’ng ◽  
Hsing-Cheng Hsi
Keyword(s):  
Organic Matter ◽  
Activated Carbon ◽  
Dissolved Organic Matter ◽  
Operational Definition ◽  
Aqueous System ◽  
Contaminated Sediment ◽  
Batch Experiments ◽  
Adsorption Performance ◽  
Negative Effect ◽  
Pseudo Second Order

Abstract Using activated carbon (AC) as thin layer capping to reduce mercury (Hg) released from contaminated sediment is a feasible and durable remediation approach. However, several aqueous factors could greatly affect the Hg fate in the aquatic system. This study thus intends to clarify the influences on Hg adsorption by AC with the presence of sulfide, dissolved organic matter (DOM), and chloride. The lab-scale batch experiments were divided into two parts, including understanding (1) AC adsorption performance and (2) Hg distribution in different phases by operational definition method. Results showed that the Hg adsorption rate by AC was various with the presence of sulfide, chloride, and DOM (from fast to slow). Hg adsorption might be directly bonded to AC with Hg-Cl and Hg-DOM complexes and the rate was mainly controlled by intraparticle diffusion. In contrast, “Hg + sulfide” result was better described by pseudo-second order kinetics. The Hg removal efficiency was 92–95% with the presence of 0–400 mM chloride and approximately 65–75% in the “Hg + sulfide” condition. Among the removed Hg, 24–29% was formed into aqueous-phase particles and about 30% Hg was adsorbed on AC with 2–20 μM sulfide. Increasing DOM concentration resulted in more dissolved Hg. The proportion of dissolved Hg increased 31% by increasing DOM concentration from 0.25 to 20 mg C L− 1. Simultaneously, the proportion of adsorbed Hg by AC decreased by 47%. Overall, the presence of chloride increases the Hg adsorption by AC. In contrast, the presence of sulfide and DOM causes a negative effect on AC adsorption.

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