Study on methane degradation by microbial agents based on chelating wetting agent carriers.

Due to the low permeability characteristics of the deep gas-containing coal seam, the conventional prevention and control measures that cannot solve the problems of gas outbursts are unsatisfactory for the prevention and control of the coal and gas outbursts disaster. Therefore, in this study, a strain of methane-oxidizing bacteria M07 with high-pressure resistance, strong resistance, and high methane degradation rate was selected from coal mines. The growth and degradation abilities of M07 in chelating wetting agent solutions to assess its adaptability and find the optimal agent-to-M07 ratio. It provides a new method for integrating the reduction of impact tendency and gas pressure in deep coal mines. The experimental results show that M07 is a Gram-positive bacterium of the genus Bacillus, which has strong resistance and adaptability to high-pressure water injection. By degrading 70 mol of methane, M07 produces 1 mol of carbon dioxide, which can reduce gas pressure and reduce the risk of gas outbursts in coal mines. As the experiment proves, the best effect was achieved when the M07 concentration of the chelating wetting agent was 0.05%. The methane-oxidizing bacteria based on the chelating wetting agent as carriers prove a new prevention and control method for the integrated prevention and control of coal and gas outbursts in coal mines and also provide a new idea for microbial application in coal mine disaster control.

Experimental study on the impact of "IDS + JFCS" complex wetting agent on the characteristics of coal bodies.

As China's coal mines have transitioned to deep mining, the ground stress within the coal seams has progressively increased, resulting in reduced permeability and poor wetting ability of conventional wetting agents. Consequently, these agents have become inadequate in fulfilling the requirements for preventing washouts during deep mining operations. In response to the aforementioned challenges, a solution was proposed to address the issues by formulating a composite wetting agent. This composite wetting agent combines a conventional surfactant with a chelating agent called tetrasodium iminodisuccinate (IDS). By conducting a meticulous screening of surfactant monomer solutions, the ideal formulation for the composite wetting agent was determined by combining the monomer surfactant with IDS. Extensive testing, encompassing evaluations of the composite solution's apparent strain, contact angle measurements, and alterations in the oxygenated functional groups on the coal surface, led to the identification of the optimal composition. This composition consisted of IDS serving as the chelating agent and fatty alcohol polyoxyethylene ether (JFCS).Subsequent assessment of the physical and mechanical performance of the coal briquettes treated with the composite wetting agent revealed notable enhancements. These findings signify significant advancements in the field and hold promising implications. Following the application of the composite wetting agent, notable reductions were observed in the dry basis ash and dry basis full sulfur of coal. Additionally, the water content within the coal mass increased significantly, leading to a substantial enhancement in the wetting effect of the coal body. This enhanced wetting effect effectively mitigated the coal body's inclination towards impact, thereby offering technical support for optimizing water injection into coal seams and preventing as well as treating impact ground pressure.

Study on the effect of SDBS and SDS on deep coal seam water injection.

Coal seam water injection, as an important disaster prevention means in the process of coal mining, can effectively suppress coal dust, add water injection additives, can effectively improve the wettability of coal body, improve the permeability of coal body, so as to achieve the prevention of rock burst. To improve the wettability of coal in coal seam water injection, the surfactant is often added to water, but sodium dodecyl benzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS) have limitations in improving wettability of deep coal seam by injecting water. Therefore, it is very important to determine the influencing factors of SDBS and SDS to improve the wettability of coal. In this paper, the effects of oxygen-containing functional groups and minerals in coal on the wettability of coal are revealed, and the wettability mechanism of SDBS and SDS is expounded from the microscopic point of view. SEM was used to characterize the interaction between coal surface and surfactant, and the contact angle experiment was used to verify the influence of minerals in coal on wettability. Inductively coupled plasma atomic emission spectroscopy (ICP) and dynamic light scattering (DLS) tests were used to characterize the interaction of SDBS, SDS with minerals and the size of precipitation generated by the interaction of SDBS, SDS and mineral ions. The results showed that SDBS and SDS interact with Ca2+ to produce precipitation and block the flow of water in coal, which is not conducive to improving the wettability of deep coal seam to a certain extent. The significant chelating effect of chelating agent and Ca2+ provides a feasible solution to this problem.

Effects of mine water on growth characteristics of ryegrass and soil matrix properties.

Irrigation with mine water not only improves water resource utilization rates and alleviates water shortages but can also promote crop growth and yields. However, long-term irrigation with mine water can significantly change the physicochemical properties of soil due to its unique mineral content. In this study, two groups of experiments were conducted (pot experiments and soilless cultivation) using mine water from the Fushun mining area to explore its effects on the physiological and photosynthetic characteristics of ryegrass, as well as soil properties. Mine water irrigation inhibited all of the indicators evaluated in this study, whereas a mixture of clean water and mine water had a stimulatory effect. Interestingly, this stimulatory effect was weakened as the proportion of mine water increased but reached its maximum when the ratio was 2:1. Moreover, the inhibitory effect of the irrigation water was weakened as the proportion of clean water increased. The contents of K+, Na+, Ca2+ and Mg2+ in soil were higher than those in the soil matrix, and the content of the nutrient elements N, P and K, and metal cations increased gradually as the mine water ratio increased, and the electrical conductivity increased significantly. Moreover, the pH of the soil decreased steadily (i.e. acidity increased) with increased soil salinity. Our findings indicated that a mixture of mine water from Fushun mining area and clean water at a 1:2 ratio could improve the physiological, growth, and photosynthetic characteristics of ryegrass by enhancing soil quality. Our study thus provides an experimental precedent for the utilization of mine water in ecological restoration and agricultural irrigation, and could therefore serve as a basis for the development of novel strategies for environmental restoration and the utilization of water resources.