Study of Compositions for Selective Water Isolation in Gas Wells

A hydrophobic composition containing water repellents and highly volatile solvents is shown in this study to isolate water from the bottomhole formation zone of gas wells and reduce as much as possible the saturation of pore spaces with water. During injection, this composition shows selectivity and mostly penetrates water-saturated porous media. The study shows that the injection of such composition into porous media has a high water-insulating effect, reducing the water permeability of water-saturated porous media by 35 times with a degree of water isolation of 97%. Moreover, while injecting, it has selective action, mainly penetrating water-saturated media rather than gas-saturated media. As a result of injecting 0.91 to 0.99 pore volumes (pv) of the composition, the Qwater/Qgas ratio reaches 5.22 to 5.26, indicating high selectivity.

Cellulose and Its Nano-Derivatives as a Water-Repellent and Fire-Resistant Surface: A Review

The inevitable destructive effects of moisture and temperature are obvious in cellulosic and nanocellulosic substrates. These materials are the main foundations of interdependent industries that produce products such as currency notes or high-quality packaging for sanitary, cosmetics, or ammunition in the defense industry. Therefore, it is essential to develop procedures to eliminate problems arising from humidity and fire to improve the quality of these green and sustainable materials. The production of waterproof and flame-resistant cellulose-based substrates has drawn increasing attention to resolve these drawbacks. In this review paper, we have initially summarized the most accessible cellulosic substrates, different kinds of nanocellulose, and the general information about water repellents and intumescent fireproof surfaces. Then, the potential and necessity of using cellulosic biobased substrates are addressed for use in modified shapes as waterproof and fire inhibitor coatings. Cost-effective, eco-friendly, and durable, dual-function coatings are also introduced as future challenges, which are exploited as water-repellents and flame-retardant cellulose-based surfaces for pulp and paper applications.

Methyl Potassium Siliconate and Siloxane Inhibit the Formation of Multispecies Biofilms on Ceramic Roof Tiles: Efficiency and Comparison of Two Common Water Repellents

Ceramic roof tiles are widespread marketed building materials, rapidly colonized by microorganisms that form multispecies biofilms on their surface and play crucial roles in biodeterioration processes. Coating tiles with water repellents is a pervasive industrial strategy employed to prevent liquid water penetration and slow biodeterioration. Very few studies have examined the links between the characteristics of water-repellent coatings and biofilm colonization patterns. Our work aims to compare the effects of coating tiles with two common water repellents (siliconate and siloxane) on the growth of colonizing microbes. We combined in situ exposure of tiles for over six years and macroscopic and microscopic observations with in vitro biotests, relying on the use of algal and fungal models. Our data showed that (1) tiles coated with water repellents were macroscopically less colonized by lichens (2) a significant fungal biofilm development at the microscopic scale (3) water repellents had very contrasting effects on our model strains. These data reinforce the great interest for industry to conduct more studies linking the nature of the water repellents with the composition of colonizing multispecies biofilms. The long-term objective is to improve the available water repellents and better adapt their selection to the nature of microbial colonization.

Production of oleophilic sorbent and studying its oil absorption properties

In recent years, in the sphere of water purification, there has been successfully developed the direction of producing effective sorbents of petroleum products associated with altering the nature of their surface with compounds of various classes. An effective method is the hydrophobization process involving a special processing of materials by immersion in solutions or melts of water repellents, spraying them on the surface, etc. As water repellents, there are used silicon organic compounds, paraffin, monoalkyl ethers of polyethylene glycol, high molecular weight compounds, etc. The hydrophobizer itself must have good adhesion to the material and, being evenly distributed during the processing, it can form bonds with the surface, which will allow it not to be washed out and not to dissolve further during operation. However, hydrophobization has some disadvantages, such as the complexity of obtaining a modified surface which would be resistant to leaching, a considerable material consumption, a high cost, etc. In this work, we have investigated the possibilities of hydrophobization of expanded perlite with quaternary ammonium salts in order to reduce its water absorption. The optimal parameters of the hydrophobization process have been established. It is shown that among the used ammonium modifiers, the greatest beneficial effect is observed for catamine AB-18: under static conditions, the sorption capacity of expanded perlite samples modified with its 1 % solution is 2-3.5 times higher than the corresponding indicator of the original.

Density, hardness and strength properties of densified fir and aspen woods pretreated with water repellents

In this study, the effect of thermo-mechanical densification on the density, hardness, compression strength, bending strength (MOR), and modulus of elasticity (MOE) of fir and aspen wood pretreated with water repellents was analyzed. Wood specimens were impregnated with paraffin, linseed oil and styrene after pre-vacuum treatment. Then, the impregnated wood specimens were densified with compression ratios of 20 and 40%, and at 120, 150 and 180 °C. The results indicated that the density, hardness and strength properties of the all densified specimens (untreated and impregnated) increased depending on the compression ratio and temperature. For all tested properties, higher increases were obtained in the paraffin and styrene pretreated specimens compared to untreated samples. However, the increase rates in linseed oil pretreated specimens were generally lower than untreated specimens. Regarding water repellents the most successful results in all tested properties were determined in styrene pretreated specimens. The density, hardness and strength properties of all specimens increased with the increase in compression ratio. On the other hand, the increase in the compression temperature negatively affects the properties of untreated and linseed oil pretreated specimens, while having a generally positive effect on the properties of paraffin pretreated specimens. However, all tested properties of styrene pretreated specimens have increased significantly due to the increase in compression temperature. The increasing strength properties of wood as a result of densification have increased much more with paraffin and especially styrene pretreatment. These combinations can be considered as an important potential for applications that require more hardness and strength.

Effect of Water Proofing Materials on Self-Healing Concrete

Improving the strength of the concrete structures and increasing the service life is an important issue. The service times of the concrete remained; external factors such as water penetrating into these micro-cracks and shorten the life of the concrete. In order to solve this problem, the idea of self-healing concrete with bacteria or other materials has been put forward and studies have shown that using CaO based materials that repair cracks in this direction by precipitating calcite. It is obvious that long term performance of concrete will increase with to prevent water pass to concrete interior. Instead of forming a barrier on the positive or negative side of concrete, water proofing admixture turn the concrete itself into a water barrier. Internal concrete waterproofing systems can be water repellents or crystalline admixtures. In this study, water proofing admixture was added to concrete mixture as water proofing material and its effect on self-healing in terms of filling the pores was investigated. Beam samples including the CaO based water proofing powder materials were produced in size of 285x75x25 mm. The samples were cracked in the flexural machine. After some days, the cracks were investigated by microscope. Crak control was continued till 28 days. At the end of study, the cracks smaller than 0.3 mm were self-healed. However, the bigger cracks than 0.3 mm cannot be self-healed by water proofing material. Consequently, self-healing of concrete with CaO based water proofing powder material is very promising for the environmentally friendly and sustainable structures of the future.