Adsorption-desorption behavior of selected pesticides in some Western Australian soils

Soil Research ◽  
1990 ◽  
Vol 28 (2) ◽  
pp. 227 ◽  
Author(s):  
R Singh ◽  
RG Gerritse ◽  
LAG Aylmore
Keyword(s):  
Organic Matter ◽  
Chemical Properties ◽  
Type Equation ◽  
Dilution Method ◽  
Sorption Data ◽  
Freundlich Isotherms ◽  
Physico Chemical ◽  
Pesticide Adsorption ◽  
Adsorption Desorption ◽  
Western Australian

The adsorption-desorption behaviour of four pesticides, in four Western Australian soils differing in their physico-chemical properties, has been studied using a batch technique. Sorption data for Fenamiphos, Linuron and Simazine could be fitted to a Freundlich-type equation, while that for Diquat more closely fitted the Langmuir equation. The value of the exponent in the fitted Freundlich isotherms varied from 0.70 to 1.00 for the various pesticide and soil combinations. Adsorption was found to be better correlated with organic matter than other soil properties, and decreased with increasing pH for all pesticides except Diquat. This study supports the observation of B. T. Bowman that the Freundlich equation in mole fraction form is more useful for comparing relative adsorption. Comparison of the present adsorption data with previous studies showed that the organic matter in these soils behaved differently in terms of pesticide adsorption. In particular, the octanol-water partition approach, for predicting the adsorption of non-ionic organic compounds, gave unsatisfactory predictions of Linuron and Fenamiphos adsorption in these soils. Desorption by a consecutive method showed hysteresis with all pesticide-soil combinations examined. The magnitude of the hysteresis was unaffected by changes in the soil : solution ratio. Using a dilution method, experimental procedures such as centrifugation and shaking have been shown to only slightly affect desorption hysteresis. The suggestion that hysteresis results from organic matter effectively 'locking in' the adsorbed pesticides is supported. The presence of methanol in the desorption solution results in swelling of organic polymers and facilitates the release of the adsorbed pesticides. Consequently, hysteresis was found to be essentially absent from the Linuron isotherm on removal of organic matter from the soil.

scholarly journals Status and Speciation of Silicon and Its Interaction with Physico-Chemical Properties

2021 ◽  
pp. 1-11
Author(s):  
Isaiah Ufuoma Efenudu ◽  
Ehi Robert Orhue ◽  
Ogochukwu Jennifer Ikeh ◽  
Michael Aimiesomon Erhayimwen ◽  
Blessing James
Keyword(s):  
Organic Matter ◽  
Acidic Medium ◽  
Soil Depth ◽  
Chemical Properties ◽  
Water Soluble ◽  
Sequential Fractionation ◽  
Soil Redox ◽  
Parent Materials ◽  
Physico Chemical ◽  
Negative Effect

The effectiveness of three different extractants soil mixtures—HCl, HCl + H2S04, and DTPA-TEA, in order to determine Si from soil and the forms of Silicon as influenced by different parent materials under acidic medium. Seven forms of Silicon; namely water soluble, specifically adsorbed, oxides bound, organic matter bound, exchangeable, residual, total viz sequential fractionation. Extractable Si value established in this study was (50.0 mg kg-1), indicating negative effect on plant physiology. The physico-chemical properties decreased significantly with increase in soil depth vs soil parent materials. In addition, the forms of Si in the parent materials decreased in the pattern RES, bound residual fractions > EXC, soluble & exchangeable fractions > OM, organic matter fraction. Among the properties the silt fraction, pH & OM significantly and positively correlated with the forms of silicon, with negative correlation vs clay which maybe due to silicon adsorption by clayey fraction of the soil (redox). Therefore the soil maybe be maintained and conserved for farming activities.

scholarly journals Effect of no tillage on the physico-chemical properties of soils of the El Koudia region, Rabat (Morocco)

2020 ◽  
Vol 150 ◽  
pp. 03010
Author(s):  
Hassnae Maher ◽  
Rachid Moussadek ◽  
Abdelmjid Zouahri ◽  
Ahmed Douaik ◽  
Houria Dakak ◽  
...  
Keyword(s):  
Organic Matter ◽  
Structural Stability ◽  
Plant Cover ◽  
Chemical Properties ◽  
Aggregate Stability ◽  
Agricultural Practices ◽  
Conventional Tillage ◽  
No Tillage ◽  
Physico Chemical ◽  
Chemical Properties Of Soils

In Morocco, agriculture is an important sector of the economy, accounting for 15 to 20% of Gross Domestic Product. However, it has faced several challenges: intensive tillage of land that has accelerated water erosion, seriously threatening water and soil potential, low plant cover density and misuse of traditional agricultural practices, causing a decrease in organic matter levels and destroying aggregate stability. Climate change is making water and soil management in agriculture more and more complicated. The major challenge for Moroccan agriculture is to increase agricultural production while preserving natural resources. The objective of our study is to evaluate the effect of no tillage (NT) on the physico- chemical properties of soil in the El Koudia experimental station, Rabat, Morocco. The crop is durum wheat, Arrehane variety. Soil samples are pre-dried, ground and screened to 0.2mm for organic matter (OM) analysis and 2mm for the remainder of the analyses. Plugs, canned, are then sintered, screened and dried for structural stability tests. The results show that no tillage (NT) favours the accumulation of surface OM, particularly at the 0-5cm horizon unlike conventional tillage (CT). The NT promotes structural stability, with a mean weight diameter (MWD) = 0.94mm for the NT compared to 0.83mm for the CT. These results show that soils ploughed in CT are more exposed to erosion degradation than soils not ploughed (NT). In addition, NT preserves soil moisture and promotes additional water retention of 5 to 10%.

Preparation of Mesoporous Silica from Rice Husk Ash: Effect of Depolymerizing Agents on Physico-Chemical Properties

2010 ◽  
Vol 93-94 ◽  
pp. 664-667 ◽  
Author(s):  
Supakij Suttiruengwong ◽  
P. Puathawee ◽  
M. Chareonpanich
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Chemical Properties ◽  
Nitrogen Adsorption ◽  
Mesoporous Silicas ◽  
Organic Residues ◽  
Hydrophobic Property ◽  
Carbon Chains ◽  
Physico Chemical ◽  
Adsorption Desorption

The aim of this work was to prepare mesoporous silicas derived from rice husk ash (RHA) using three different depolymerizing agents; glycerol, 1,3 propanediol and 1,4 butanediol. The reaction of RHA with different depolymerizing agents was carried out between 200-250°C for 2 hrs. The solution was then hydrolyzed with deionized water to obtain gels. After a few washing step, gels were oven-dried and calcined at 500 °C for 24 hrs. Prepared mesoporous silicas were then characterized using Nitrogen adsorption-desorption measurement, FTIR, TGA, SEM, XRD and XRF. The percent hydrophobicity was determined based on the amount of moisture absorbed using TGA. It was shown that RHA reacted with depolymerizing agents above 200°C to form gels, which, after hydrolysis and calcination, still maintained the mesoporous characteristics. The BET and SEM results indicated that the RHA reacted with 1,3 propanediol had highest pore volume (0.95 cm3/g) and specific surface area (129.30 m2/g) compared to RHA reacted with glycerol and 1,4 butanediol. The distribution of pores computed from BJH desorption branch was also more uniform. FTIR indicated that there was no significant change in the chemical structure of RHA reacted with different depolymerizing agents. The residual C-H bands were found in FTIR spectra for all prepared mesoporous silicas. TGA thermograms confirmed the existence of organic residues (below 2 %wt), which might result from incomplete elimination even after calcination. This was found to be an important factor affecting the hydrophobic property of the reacted RHA. The hydrophobicity of RHA may be tailored by controlling depolymerizing agents and organic residues. Depolymerizing agents with longer carbon chains also favoured the hydrophobic characteristics.

Adsorption of Cobalt Ions on Molded Magnesium Silicate

2013 ◽  
Vol 807-809 ◽  
pp. 704-707
Author(s):  
Li Li Mao ◽  
Hai Zeng Wang ◽  
Qing Wang
Keyword(s):  
Adsorption Process ◽  
Average Pore Size ◽  
Chemical Properties ◽  
Magnesium Silicate ◽  
Average Pore ◽  
Cobalt Ions ◽  
Adsorption Time ◽  
Physico Chemical ◽  
Adsorption Desorption ◽  
Adsorbent Dose

The groundwater contaminated with cobalt is attracted more and more concern. In this study, molded magnesium silicate (MMS) was successfully prepared and the physico-chemical properties were determined by N2 adsorption/desorption isotherm and Scanning Electron Microscopy (SEM). Surface area and the average pore size were 333.19 m2·g-1 and 4.442 nm. Adsorption experiments of removal of cobalt ions was investigated as the function of initial concentration, adsorbent dose and adsorption time. Adsorption process was rapid and adsorption equilibriums were achieved soon.

scholarly journals Changes in physico-chemical properties of paddy soil due to water and fertilizer management

2020 ◽  
Vol 5 (2) ◽  
pp. 65-71
Author(s):  
Israt Jahan ◽  
AKM Abul Ahsan ◽  
MMR Jahangir ◽  
Mahmud Hossain ◽  
Md Anwarul Abedin
Keyword(s):  
Organic Matter ◽  
Soil Properties ◽  
Bulk Density ◽  
Total Nitrogen ◽  
Soil Ph ◽  
Crop Production ◽  
Soil Health ◽  
Chemical Properties ◽  
Soil Samples ◽  
Physico Chemical

Soil physico-chemical properties are an important phenomenon for sustainable crop production and maintenance of optimum soil health. Hence, a laboratory measurement was conducted with soil samples of three years long experimental field of the Department of Soil Science, Bangladesh Agricultural University, Mymensingh to assess the changes in five selected soil physico-chemical properties viz. soil texture, bulk density, soil pH, total nitrogen and organic matter. The experiment was laid out in a split plot design with two water regimes (continuous flooding and alternate wetting & drying) in the main plots and five fertilizer treatments (N0 - control, N1- 140 kg N/ha as PU, N2- 104 kg N/ha as USG (2× 1.8 g/ 4 hills), N3 - 5 t CD + PU @ 140 kg N /ha on IPNS basis and N4- 5 t CD + USG (2× 1.8 g/ 4 hills @ 104 kg N/ha)) in the subplots under rice-rice cropping pattern with three replications. After three years, soil samples were collected at 0-5 and 5-10 cm soil depths for measuring bulk density and at 0-10 cm depth for other soil properties and analyzed. Results found that % sand, % silt, % clay, bulk density and soil pH was not changed significantly compared to initial status. Percentage of total nitrogen and organic matter was significantly affected by irrigation and fertilization. Total nitrogen (%) was higher in AWD whereas organic matter (%) was higher in CF practice. The highest total nitrogen (%) and organic matter (%) was found in N4 treatment in which USG was applied in combination with cowdung as organic manure. It can be suggested that N4 treatment was formed good combination for sustaining chemical properties of soil. Further long- term experimentation will be needed to know the changes in soil properties for sustainable crop production and improving soil health. Asian Australas. J. Biosci. Biotechnol. 2020, 5 (2), 65-71

scholarly journals Physico-chemical characteristics of the seasonally flooded soils of Bangladesh and their management implications

1970 ◽  
Vol 20 (2) ◽  
pp. 173-182
Author(s):  
KF Akhter ◽  
ZH Khan ◽  
MS Hussain ◽  
AR Mazumder
Keyword(s):  
Organic Matter ◽  
Organic Matter Content ◽  
Chemical Properties ◽  
Exchange Capacity ◽  
Matter Content ◽  
Flooded Soils ◽  
Management Implications ◽  
Available N ◽  
Physico Chemical ◽  
Seasonally Flooded

The seasonally flooded soils of Bangladesh are unique in respect of several specific characteristics and contribute toward producing bulk of its staple food - mainly rice. Having fine texture these soils are similar to the “paddy soils” of Southeast Asian floodplains and have high production potential under proper management. Six representative soil series, viz. Arial, Debidwar, Naraibag, Jalkundi, Siddirganj and Tippera from the central region of Bangladesh have been studied to evaluate some of their intrinsic physico-chemical properties and their sustainable management requirements. These soils are slightly acidic to neutral and are negatively charged with ΔpH values ranging between –0.2 and –1.2. The organic matter content in the surface soil is relatively low that decreases steadily with depth. The cation exchange capacity (CEC) of the soils varies on the basis of their clay and organic matter contents while base saturation per cent (BSP) is high. The contents of available N, P, K and S and DTPA-extractable Fe, Mn, Cu and Zn in soils are moderate and are commensurate with the contents of colloidal fractions. These soils receive several mineral nutrients annually with the sediments deposited during the monsoon floods. The characteristics like organic matter content, particle size distribution, CEC, pH and BSP that have important management implications have been discussed. Key words: Seasonally flooded soils; Physical and chemical attributes; Management implications DOI: http://dx.doi.org/10.3329/dujbs.v20i2.8978 DUJBS 2011; 20(2): 173-182

Adsorption of Nickel and Cobalt Ions on Magnesium Silicate

2013 ◽  
Vol 726-731 ◽  
pp. 2855-2858
Author(s):  
Hua Yang ◽  
Hai Zeng Wang
Keyword(s):  
Ph Value ◽  
Average Pore Size ◽  
Chemical Properties ◽  
Magnesium Silicate ◽  
Solution Ph ◽  
Average Pore ◽  
Cobalt Ions ◽  
Physico Chemical ◽  
Short Time ◽  
Adsorption Desorption

Magnesium silicate (MS) was successfully prepared and the physico-chemical properties were determined by N2adsorption/desorption isotherm and Scanning Electron Microscopy (SEM). Surface area and the average pore size were 120 cm3·g-1and 10 nm. Adsorption experiments of removal of nickel and cobalt ions were investigated as the function of initial concentration, adsorbent dose, adsorption time and solution pH value. The maximum removal was reached with pH equal to 5 for the removal of nickel and cobalt ions. Adsorption process was rapid and adsorption equilibriums were attained in a short time.

scholarly journals Dynamics of the Physico-chemical Properties of Sediments along the Bandama River in the Department of Niakaramadougou, Northern Côte d’Ivoire

2019 ◽  
pp. 739-750
Author(s):  
N’Doufou Gnosseith Huberson Claver ◽  
Kouadio Koffi Hypolithe ◽  
De Lasm Omer Zephir ◽  
Zogoury Eddie Constant Fabrice
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Chemical Properties ◽  
Statistical Analyses ◽  
The Other ◽  
Eastern Shore ◽  
Chemical Parameters ◽  
Sediment Analysis ◽  
Granulometric Analysis ◽  
Physico Chemical

This work focuses on analyzing of physico-chemical properties of sediment affected by frequent floods along the eastern shore of the Bandama River in the department of Niakaramadougou. Sampling was from 4 excavated graves at two positions of studied area, one near the stream and the other one far away from the stream.. Samples collected were analyzed, including texture with granulometric analysis made by the Robinson pipette, and standard sediment analysis methods for measuring organic carbon (OC), nitrogen (N), and other chemical properties including pH, organic matter (OM), and C/N ratio. Statistical analyses were carried out to assess the differences between the physico-chemical parameters at different sampling areas. Differences are significant when comparing areas that are highly affected by floods and areas that are less affected by floods, especially for concentrations of OM, OC and nitrogen. Results show that successive floods are influencing directly the dynamic of physico-chemical properties of the sediments along the shore.

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