water softening
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Surface ◽  
2021 ◽  
Vol 13(28) ◽  
pp. 188-196
Author(s):  
I. I. Voitko ◽  
◽  
V.A. Denisovich ◽  
T. V. Kibalnik ◽  
O. A. Sopruk ◽  
...  

Sorption tests carried out oxidized nitric acid active carbon in H+- and Na+- form in relation to cations Mg2+ and Ca2+ and mixture thereof. Values obtained statistical volumetric capacity samples and mass loss them during processing nitric acid, that is oxidation state. Discovered correlation between these data and relevant sorption volume samples. Demonstrated a possible water softening oxidized coal subject to specific solution acidity.


2021 ◽  
Vol 12 (1) ◽  
pp. 150
Author(s):  
Wei Zhang ◽  
Jintao Wu ◽  
Jing Xiao ◽  
Mingyao Zhu ◽  
Haichuan Yang

Protease is the main enzyme of detergent. Through the combination of different proteases and the combination of protease and detergent additives, it can adapt to different washing conditions to improve the washing effect. In this experiment, whiteness determination, microscope scanning, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy were used to detect the whiteness values of the cloth pieces before and after washing, as well as the stain residue between the fibers on the surface of the cloth pieces. The protease detergent formula with better decontamination and anti-deposition effects was selected. The combination of alkaline protease, keratinase, and trypsin was cost-effective in removing stains. Polyacrylamide gel electrophoresis showed that the molecular weight of the protein significantly changed after adding the enzyme preparation during washing, and the molecular weight of the protein was directly proportional to protein redeposition. The composite protease had a better comprehensive decontamination effect, and when compatible with suitable surfactants, anti-redeposition agents, and water-softening agents, the compound protease detergent exhibited a stronger decontamination ability than commercial detergents.


2021 ◽  
Author(s):  
Eric Delamaide ◽  
David Rousseau ◽  
Nicolas Wartenberg ◽  
Mathieu Salaun

Abstract The first surfactant-based pilots can be traced back to the 1960s and since then almost a hundred field tests have taken place. Interestingly, almost half of these pilots have used an alkali (ASP) and the other half has not (SP). This reflects the current status of the industry which is divided along the same lines and over the same question: do surfactant-based processes require alkali or not? This paper proposes to address this question by providing explanations and discussing case studies. The paper will start by reminding the reader of the role of both surfactant and alkali and will review the pros and cons of alkali in terms of formulation performances, adsorption but also surface facilities and logistics. Several cases studies (lab and field) will be discussed to show when alkali can and cannot be used, and what solutions are available as alternatives to the use of alkali. Although alkali allows reducing both surfactant concentration and adsorption, it can also cause severe scaling and requires additional facilities including water softening; in addition, the large volumes of alkali required can cause logistical challenges. On the other hand, the main challenges of formulations without alkali is finding surfactants that can develop a low enough Interfacial Tension and low adsorption, or to find an acceptable adsorption mitigation strategy such as salinity gradient or adsorption inhibitors. In the early years of SP projects, very high surfactant concentrations were used (micellar process) and the process was not economic; as a result, alkali was seen as the only realistic solution. This appears to no longer be the case due to the developments of new surfactants. Although most projects in recent years have favoured the use of alkali, it seems that a trend towards SP is growing, with recent field projects in Kuwait, Oman, China and Russia favouring the SP solution. This paper will provide a discussion on the pros and cons of the use of alkali in surfactant-based processes. It will show that although using alkali has been a standard for many years it also entails severe surface issues such as scaling and requires additional capital for water softening and logistics. More importantly, recent developments in surfactants now seem to provide alkali-free solutions that can compete in terms of formulation performances. This now needs to be confirmed in the field.


2021 ◽  
pp. 69-112
Author(s):  
M.H. Tajuddin

This chapter discusses about nanofiltration (NF) membrane for water softening and desalination. The NF membrane system and thin film composite (TFC) membranes are discussed in general followed by their drawbacks. Next, recent trend of nanofillers in thin film nanocomposite (TFN) membrane is critically discussed and highlighted. The advantages and challenges of TFN membrane for water softening and desalination application are thoroughly analyzed. Lastly, the future directions of the TFN membrane for practical application are addressed.


2021 ◽  
Author(s):  
Zheng Yang ◽  
Ning Guo ◽  
Heng Zhang

Based on the Xigeda clay rock exposed in the back mountain of Nanshan Villa in Xichang City, the microstructure changes of Xigeda clay rock before and after water softening were studied by scanning electron microscope and image recognition of PCAS software. The results show that: (1) the clay rock of Xigeda group has flake and layered micro structural characteristics, and the surface of aggregates in natural state has honeycomb characteristics. After water softening, the aggregate particles decompose, the average size of particles becomes smaller, the honeycomb characteristics disappear, and the surface contours of particles become smooth and round. (2) With the increase of water saturation time, the number of aggregate particles and pores increases, the porosity decreases in advance and increases in the later stage. (3) Micro structural changes of the clay rock in Xigeda formation have two stages, in the first stage, the aggregates decompose and the produced fine granular clays fill the original pores, resulting in the decrease of porosity.In the second stage, the fine clay particles further soften, decompose and lose in the water, the porosity increases suddenly.


2021 ◽  
Vol 50 (5) ◽  
pp. 349
Author(s):  
B. M. D. S. Balasuriya ◽  
S. R. W. M. I. S. Bandara ◽  
N. Kottegoda ◽  
A. D. L. C. Perera

Author(s):  
Zhonghao Wang ◽  
Wei Lin ◽  
Wei Wang ◽  
Zhangwei Wang ◽  
Jimin Li ◽  
...  

Abstract In order to promote the application of electrochemical water softening technology in industrial circulating cooling water systems, electric field type, cathode structure and solution residence time are selected for optimization analysis of electrochemical water softening device. The experimental results show that the water softening performance per unit area of mesh cathode is better than that of plate cathode. In addition, the softening amount per unit area of the mesh cathode can be further increased when the high-frequency (HF) power supply is applied. When the HF power supply is applied, the softening amount per unit area is 158.58 g/m2·h−1 more than that the direct current power supply is applied. In order to explore the growth mechanism of calcium carbonate, micro-analysis technology and high-speed bubble photography technology are used. The results show that the bubbles escape along the longitudinal direction of the electrode plate, and the main growth direction of calcium carbonate growth is consistent with the escape direction of the bubble, that is, the bubbles grow along the longitudinal direction of the electrode plate. The special structure of the diamond-shaped mesh cathode facilitates the growth of calcium carbonate crystals.


2021 ◽  
Vol 11 (19) ◽  
pp. 8906
Author(s):  
Wenqi Ding ◽  
Shi Tan ◽  
Rongqing Zhu ◽  
He Jiang ◽  
Qingzhao Zhang

The weakening effect is one of the most important causes triggering large deformation and failure of soft-rock engineering; however, few studies paid attention to damage evolution and constitutive relationship of rock in tensile damage in the excavation unloading and water-weakening process, not to mention the coupling process of unloading and water-weakening. In this paper, the mechanism and engineering characteristics of unloading softening and water-softening of water-rich soft rock are analyzed and summarized. Then with the aid of the strain equivalent principle, the damage of surrounding rock caused by unloading softening and water-softening is coupled, and the compression shear damage and the tensile damage of surrounding rock under the unloading process are analyzed. A damage constitutive model of rock subjected to excavation unloading and water-weakening is proposed considering the influence of water immersion time, and the proposed model is applied in a newly established finite element simulation method, which is suitable for excavation in the water-rich soft rock. Based on the mechanical-hydraulic-damage coupled method, the progressive failure process of surrounding rock under the dual softening effects can be reflected by the deteriorated parameters of damage elements. Finally, the field monitoring data of a typical section in the Xujiadi tunnel is used to verify the applicability and accuracy of the proposed dual softening model and simulation method.


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