scholarly journals DFT Study of The Interaction Characteristics Between the Organic Matter and Minerals In Coal-Series Kaolin

Author(s):  
Teng Huang ◽  
Lei Shaomin ◽  
He Zhihao ◽  
Man Chen ◽  
Men Li

Abstract Coal-series kaolin is an associated mineral resource in coal mining process, often contains organic components and other discoloring impurities, which may lower the quality and limit the industrial application. However, the occurrence, stability of organic component and how they affect the surface physical and chemical properties of coal-series kaolin is known little. In this article, several representative organic components have been enrolled for analyzing the interactions with different minerals of the coal-series kaolin. Results shows that the unsaturated double bonds may be easier to adsorb with kaolinite, and the energy on C20H40 is the least among all the compositions. Among the different crystal planes of kaolinite, the (001) surface may possess higher adsorption characteristic on the organic molecules, which may be consistent with the crystal face index of the kaolinite. While the adsorption energy between the organic molecules and the impurities in coal-series kaolin was positive all the time, suggesting that the organic matter could only adsorb with kaolinite compared with the impurities such as pyrite, quartz and anatase. Calculations of state density also showed that the displacement of the energy band for kaolinite may shift to the lower state after adsorbed with different organic matter, also a rearrangement and significant increase of peak values for the state density may occur after adsorption. This study aims to provide a theoretical basis for the occurrence state and stability differences of different organic matters on the coal-series kaolin, also further solve the long-term problems of restricting the whiteness and comprehensive utilization of coal-series kaolin resources.

2016 ◽  
pp. 43-48
Author(s):  
Judit Horváth ◽  
Bence Mátyás ◽  
János Kátai

The soil is a natural resource, the fertility preservation is an important part of the sustainable development. We have to monitor the transformation dinamics of the organic nitrogen-containing substances, to get accurate information about the changes of the nitrogen cycle in the soil. Physical and chemical properties of the soil and the microorganism effect on the organic matter in the soil – in addition to the composition of organic matter. Wide variety of extracellular enzymes are present in this decomposition. These enzymes help in the transformation of the macromolecules to transforming low molecular weight compounds so they will be available during the assimilation. The urease enzyme, catalyzes the hydrolysis of urea to CO2 and NH3. The urease is widely spread in the nature, it is present in the microorganisms, plants and animals. We found that the soil moisture content, the rotation and the fertilization affect to the amount of urease in spring. Furthermore, we get significant difference between the irrigated and non irrigated samples in the second period of the year. Based on our results we can state that the activity of urease was higher in spring 2014. The objective of our study was to present how the different agronomic factors affect on the activity of urease in a long term fertilizationexperiment.


Author(s):  
Amita M Watkar ◽  

Soil, itself means Soul of Infinite Life. Soil is the naturally occurring unconsolidated or loose covering on the earth’s surface. Physical properties depend upon the amount, size, shape, arrangement, and mineral composition of soil particles. It also depends on the organic matter content and pore spaces. Chemical properties depend on the Inorganic and organic matter present in the soil. Soils are the essential components of the environment and foundation resources for nearly all types of land use, besides being the most important component of sustainable agriculture. Therefore, assessment of soil quality and its direction of change with time is an ideal and primary indicator of sustainable agricultural land management. Soil quality indicators refer to measurable soil attributes that influence the capacity of a soil to function, within the limits imposed by the ecosystem, to preserve biological productivity and environmental quality and promote plant, animal and human health. The present study is to assess these soil attributes such as physical and chemical properties season-wise.


2015 ◽  
Vol 63 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Karsten Schacht ◽  
Bernd Marschner

Abstract The use of treated wastewater (TWW) for agricultural irrigation becomes increasingly important in water stressed regions like the Middle East for substituting fresh water (FW) resources. Due to elevated salt concentrations and organic compounds in TWW this practice has potential adverse effects on soil quality, such as the reduction of hydraulic conductivity (HC) and soil aggregate stability (SAS). To assess the impact of TWW irrigation in comparison to FW irrigation on HC, in-situ infiltration measurements using mini disk infiltrometer were deployed in four different long-term experimental orchard test sites in Israel. Topsoil samples (0-10 cm) were collected for analyzing SAS and determination of selected soil chemical and physical characteristics. The mean HC values decreased at all TWW sites by 42.9% up to 50.8% compared to FW sites. The SAS was 11.3% to 32.4% lower at all TWW sites. Soil electrical conductivity (EC) and exchangeable sodium percentage (ESP) were generally higher at TWW sites. These results indicate the use of TWW for irrigation is a viable, but potentially deleterious option, as it influences soil physical and chemical properties.


2016 ◽  
Vol 13 (1) ◽  
pp. 1-6
Author(s):  
Baghdad Science Journal

Soil invertebrates community an important role as part of essential food chain and responsible for the decomposition in the soil, helps soil aeration , nutrients recycling and increase agricultural production by providing the essential elements necessary for photosynthesis and energy flow in ecosystems.The aim of the present study was to investigate the soil invertebrates community in one of the date palms plantation in Aljaderia district South of Baghdad, , and their relationships with some physical and chemical properties of the soil , as Five randomly distributed replicates of soil samples were collected monthly. Invertebrates samples were sorted from the soil with two methods, direct method to isolate large invertebrates and indirectly to isolate small invertebrates using wet funnel method. The study also included the determination of physical and chemical factors of the soil (Temperature, Salinity, pH, Organic matter, Humidity, In addition to the soil texture).Monthly fluctuations in physical and chemical characteristics of the soil and the total invertebrates community study site were determined. Significant correlations the of the invertebrates community and each of temperature, organic matter, and humidity were observed. The study revealed that the temperature of the soil ranged between 5 to 25 C0 , The salinity concentration ranged between 1.1-1.9 ‰, The pH values ranged between 7.3 to 7.8 and the percentage of soil moisture ranged between 15 - 25% , Soil samples were composed of 44.6 % Clay, 19.7% Silt and 35.5% Sand.A total of 4625 individuals of soil invertebrates belonging to 16 taxa were sorted , within which the adult and larval insects were the most abundant, and from them 1283 individuals were sorted , represented 28% of the total numbers, followed by Isopoda , which 1030 individuals of them were sorted, In addition to Nematode, Oligochaetes Annelids family Enchytraeidae, and Earthworms family Lumbricida, Species of Chilopoda, Diplopoda, mites, land snails and slugs. The highest total individual number were recorded recorded durim moderate temperature months, February, March and April amounted to 838, 801 and 813 individuals, respectively.A significant correlation was mated between total number of soil invertebrates and each of temperature, organic matter and humidity. The significant difference in means was calculated according to LSD test.


Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1026
Author(s):  
Keith Bateman ◽  
Shota Murayama ◽  
Yuji Hanamachi ◽  
James Wilson ◽  
Takamasa Seta ◽  
...  

The construction of a repository for geological disposal of radioactive waste will include the use of cement-based materials. Following closure, groundwater will saturate the repository and the extensive use of cement will result in the development of a highly alkaline porewater, pH > 12.5; this fluid will migrate into and react with the host rock. The chemistry of the fluid will evolve over time, initially high [Na] and [K], evolving to a Ca-rich fluid, and finally returning to the groundwater composition. This evolving chemistry will affect the long-term performance of the repository, altering the physical and chemical properties, including radionuclide behaviour. Understanding these changes forms the basis for predicting the long-term evolution of the repository. This study focused on the determination of the nature and extent of the chemical reaction, as well as the formation and persistence of secondary mineral phases within a mudstone, comparing data from sequential flow experiments with the results of reactive transport modelling. The reaction of the mudstone with the cement leachates resulted in small changes in pH with the precipitation of calcium aluminium silicate hydrate (C-(A-)S-H) phases of varying compositions. As the system evolves, secondary C-(A-)S-H phases re-dissolve and are replaced by secondary carbonates. This general sequence was successfully simulated using reactive transport modelling.


2012 ◽  
Vol 36 (4) ◽  
pp. 1299-1310 ◽  
Author(s):  
Carolina Tirloni ◽  
Antonio Carlos Tadeu Vitorino ◽  
Anderson Cristian Bergamin ◽  
Luiz Carlos Ferreira de Souza

Crop-livestock integration represents an interesting alternative of soil management, especially in regions where the maintenance of cover crops in no-tillage systems is difficult. The objective of this study was to evaluate soil physical and chemical properties, based on the hypothesis that a well-managed crop-livestock integration system improves the soil quality and stabilizes the system. The experiment was set up in a completely randomized design, with five replications. The treatments were arranged in a 6 x 4 factorial design, to assess five crop rotation systems in crop-livestock integration, and native forest as reference of soil undisturbed by agriculture, in four layers (0.0-0.05; 0.05-0.10; 0.10-0.15 and 0.15-0.20 m). The crop rotation systems in crop-livestock integration promoted changes in soil physical and chemical properties and the effects of the different systems were mainly detected in the surface layer. The crops in integrated crop-livestock systems allowed the maintenance of soil carbon at levels equal to those of the native forest, proving the efficiency of these systems in terms of soil conservation. The systems influenced the environmental stability positively; the soil quality indicator mineral-associated organic matter was best related to aggregate stability.


2005 ◽  
Vol 52 (10-11) ◽  
pp. 61-68 ◽  
Author(s):  
E.-H. Choi ◽  
B. Klapwijk ◽  
A. Mels ◽  
H. Brouwer

Wastewater contains various organic components with different physical and biochemical characteristics. ASM No. 1 distinguishes two categories of biodegradable organic matter in wastewater, rapidly and slowly biodegradable. In general there are two methods for wastewater characterization: based on filtration in combination with a long-term BOD test or based on a respirogram. By comparing both approaches, we showed that in wastewater three categories of organic compounds with different biodegradation rates can be distinguished. These categories are referred to as readily biodegradable, rapidly hydrolysable and slowly hydrolysable organic matter. The total biodegradable COD can be found from a long-term BOD-test combined with a curve-fit and the readily biodegradable and rapidly hydrolysable from a respirogram. The slowly hydrolysable is the difference between total biodegradable COD and the sum of readily biodegradable and rapidly hydrolysable COD. Simulation with characterization based on filtration for a pre-anoxic reactor with a certain N-removal compared with the N-removal of the same plant with wastewater according to the modified characterization shows different results of each wastewater, especially with regard to the effluent nitrate concentration.


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