Adsorption characteristics of tetracycline by two soils: assessing role of soil organic matter

Soil Research ◽  
2009 ◽  
Vol 47 (3) ◽  
pp. 286 ◽  
Author(s):  
Yanyu Bao ◽  
Qixing Zhou ◽  
Yingying Wang
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Equilibrium Concentration ◽  
Red Soil ◽  
Batch Adsorption ◽  
Equilibrium Time ◽  
Adsorption Characteristics ◽  
Hydrous Oxides ◽  
Cinnamon Soil ◽  
Different Soils

The adsorption characteristics of tetracycline by 2 soils including a clay-rich soil (cinnamon soil) and an iron oxide-rich soil (red soil) were investigated as a function of soil organic matter (SOM). SOM is the main adsorbent for tetracycline in the soil environment. The results indicated that the adsorption kinetics of tetracycline by the different soils with or without organic matter was described by the Elovich equation and the exponent equation. The adsorption of tetracycline on red soil was quite rapid and equilibrium could be reached after 5 h. In contrast, the concentration of tetracycline in cinnamon soil reached equilibrium after 11 h. The difference in equilibrium time in cinnamon soil and red soil was caused by their dominant components for adsorption, including clays, organic matter, and Al/Fe hydrous oxides. It took longer for the penetration of tetracycline into the interlayers between clays and organic matter in cinnamon soil, but tetracycline needed less time for adsorption through surface complexation on oxide surfaces of red soil. Removing SOM from soil markedly shortened the equilibrium time (7 h) of adsorption and reduced the equilibrium concentration (Cs) in cinnamon soil, but not in red soil, because of different dominant components for adsorption in the 2 natural soils. In natural and SOM-free soils, >98% of tetracycline in solution could be sorbed. The adsorption of tetracycline on natural and SOM-free soils was well described by Freundlich adsorption isotherms. Batch adsorption experiments showed that the adsorption of tetracycline on natural red soil was stronger than that on natural cinnamon soil. Adsorption capacity (KF) decreased with an increase in SOM removed from soil, which is attributed to the effect of tetracycline sorbed by SOM in different soils. However, SOM affected the adsorption intensity (n) of different soils diversely; there was a decrease for red soil and an increase for cinnamon soil. In particular, red soil with high Al/Fe hydrous oxides had higher adsorption affinities than cinnamon soil.

The Influence of Biochar on Adsorption Behaviour of Triazine Herbicides in Different Soil Types

2021 ◽  
Author(s):  
Nadežda Stojanov ◽  
Tijana Zeremski ◽  
Snežana Maletić ◽  
Milorad Živanov ◽  
Jelena Tričković
Keyword(s):  
Organic Matter ◽  
Adsorption Capacity ◽  
Single Point ◽  
Organic Matter Content ◽  
Equilibrium Concentration ◽  
Soil Types ◽  
Batch Adsorption ◽  
Triazine Herbicides ◽  
Point Distribution ◽  
Adsorption Sites

<p>Biochar is promising material used to enhance organic matter content in soil and to mitigate climate change through carbon sequestration. In addition to that, biochar increases crop yield by means of improving soil capacity for water- and nutrient-holding capacity, and due to its adsorption capacity, it decreases mobility and bioavailability of organic pollutants and heavy metals. Biochar (BC) is a carbon-rich and porous material produced by pyrolysis of biomass under oxygen-limited conditions. The unwanted spread of pesticides to the environment and their leaching into the groundwater is of great concern. The aim of this work is to investigate the potential of BC to improve the adsorption capacity for two triazine herbicides in three different soil types with various organic matter (OC) content. Triazine herbicides (terbuthylazine and atrazine) were chosen as the most widely used pesticides in recent decades. The main difference among between three different soils types used in the study is in their OM content, which was 0.48%, 2.34% and 4.12%, respectively for Soil1, Soil2, and Soil3. The BC used in this work is commercially available compost-activated biochar produced by pyrolysis of beechwood chips at 700 <sup>o</sup>C. A batch adsorption experiments were conducted to investigate herbicide adsorption in soil without BC and with the amendment of BC (0, 1, 5, and 10%). The concentration of herbicides in the aqueous phase at equilibrium (which is achieved after 72 h) was determined by GC-MS. The adsorption isotherms were well described with the Freundlich model (R<sup>2</sup> values range from 0.714 to 0.998). Values of Freundlich exponent <em>n</em> were less than 1 (from 0.314 to 0.897), which indicates that the isotherms are of L-type. This shows that with the increase of compound concentration relative adsorption decreases because of the saturation of adsorption sites. Single-point distribution coefficients (<em>K<sub>d</sub></em>) were calculated at selected equilibrium concentration (<em>c<sub>e</sub></em>= 100 µg dm<sup>–3</sup>). <em>K<sub>d</sub></em> values increased with an increase of BC content, especially for 5% and 10% of BC amendment. <em>K<sub>d</sub></em> values of atrazine in Soil1 were in the range 1.91–14.55, in Soil2 from 4.76–15.65, and in Soil3 from 4.79–20.11, while <em>K<sub>d</sub></em> values of terbuthylazine ranged from 1.14–30.92 in Soil1, from 14.13–50.74 in Soil2, and from 12.65–47.03 in Soil3. In unamended Soil1 the adsorption of both herbicides was lower in comparison to unamended Soil2 and Soil3, which is in accordance with the well-known fact that the OC content of soil primarily affects the adsorption of pesticides. The adsorption capacity of Soil 2 and Soil 3 was not significantly different. It is observed that the adsorption of terbuthylazine is higher in all soil types, which is in accordance with its lower solubility and higher affinity for OM in comparison to atrazine. It is shown that sorption capacity of soil for pesticides could be improved by adding biochar into the soil, thus reducing herbicide mobility into the environment. Further studies will be conducted by column experiments to investigate more realistic environmental scenarios.</p>

scholarly journals Modelling organic matter dynamics in different soils.

1990 ◽  
Vol 38 (3A) ◽  
pp. 221-238 ◽  
Author(s):  
E.L.J. Verberne ◽  
J. Hassink ◽  
P. de Willigen ◽  
J.J.R. Groot ◽  
J.A. van Veen
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
State Level ◽  
N Cycling ◽  
First Order ◽  
Soil Microbial ◽  
First Order Kinetics ◽  
Different Soils

A mathematical model was developed to describe carbon (C) and nitrogen (N) cycling in different soil types, e.g. clay and sandy soils. Transformation rates were described by first-order kinetics. Soil organic matter is divided into four fractions (including microbial biomass pool) and three fractions of residues. The fraction of active soil organic matter was assumed to be affected by the extent of physical protection within the soil, as was the soil microbial biomass. The extent of protection influenced the steady state level of the model, and, hence, the mineralization rates. The mineralization rate in fine-textured soils is lower than in coarse-textured soils; in fine-textured soils a larger proportion of the soil organic matter may be physically protected. The availability of organic materials as a substrate for microorganisms is not only determined by their chemical composition, but also by their spatial distribution in the soil. (Abstract retrieved from CAB Abstracts by CABI’s permission)

The effects of soil type on the early growth of lettuce

1986 ◽  
Vol 107 (1) ◽  
pp. 1-8 ◽  
Author(s):  
P. A. Costigan
Keyword(s):  
Growth Rate ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Plant Growth ◽  
Soil Surface ◽  
Early Growth ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Negative Effect ◽  
Different Soils

SUMMARYLarge and consistent differences in growth rate of lettuce on different soils were recorded in two consecutive experiments in which lettuce cv. Avondefiance was grown for about 4 weeks in miniplots of 13 different soils. The miniplots were 20 cm in diameter and 20 cm deep and were buried flush with the soil surface at a single site. Each soil received the recommended amount of fertilizer and only seedlings emerging on a particular day were allowed to grow on. The relative performance of the different soils was very similar in each of the experiments with the plants in the best soil being 2·2–3·3 times heavier than those on the worst soil by the end of the experiments. The relative growth rates (RGR) of the plants were positively correlated with % P in the plants (accounting for 44–68% of the variation in RGR) and in turn with the availability of P in the soil. There was also a negative effect of soil organic matter on RGR, acting independently of % P, so that a multiple regression with % P and organic matter accounted for 65% of the variance of RGR in Expt 1 and 75% in Expt 2. Soil solution phosphorus appeared to be a useful measure for assessing phosphorus availability as plant growth was reduced only when concentrations fell below about 1 μg/ml.

scholarly journals Modification of the standard method for determination of non-exchangeable NH4-N in soil

2012 ◽  
Vol 58 (No. 12) ◽  
pp. 557-560 ◽  
Author(s):  
P. Beuters ◽  
H.W. Scherer
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Standard Method ◽  
Hydrofluoric Acid ◽  
Soil Samples ◽  
Arable Soils ◽  
N Dynamics ◽  
Different Soils

It is well accepted that non-exchangeable NH<sub>4</sub>-N plays an important role in the N dynamics of arable soils. However the widely-used Silva/Bremner method for determining this N fraction is very time consuming and the use of the hazardous hydrofluoric acid (HF) is indispensable. In the modification the use of HF is avoided and the quantity of analysed samples per unit of time could be increased by a factor of 2.5. After pretreating soil samples with KOBr to destroy soil organic matter soil samples are dried and the content of non-exchangeable NH<sub>4</sub>-N is measured using a CNS analyzer. The results of the analysis of 3 out of 4 different soils show no significant differences between both methods. &nbsp;

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