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Review of Basic Chemistry and Geology
Published in Arthur W. Hounslow, Water Quality Data, 2018
Alkali metals are those elements with one electron in the s orbital. They include lithium, sodium, potassium, rubidium, and cesium. Alkali metals have oxides that are very soluble in water and produce a strongly alkaline solution. Most of the alkali salts are soluble in water. They have an oxidation state of (I) only. They occur naturally in the secondary environment as evaporites and brines. They are also the dominant species in silicate minerals.
Synthesis and properties of sodium isotridecyl polyoxyethylene ether sulfate with different ethylene oxide addition numbers
Published in Journal of Dispersion Science and Technology, 2022
Penghui Li, Shengti Cao, Yueqing Huo, Xiaochen Liu
The tolerance of anionic surfactants to salt or alkali plays a key role in practical applications, such as industrial cleaning, separation process based on oil field or improving oil recovery. Generally, when the content of salt or alkali in the surfactant solution reaches a certain critical value, the micelle structure is destroyed and salting out occurs, and the surfactant will not play its effective role.[41] Therefore, the development of surfactant products with good alkali/salt resistance will help to expand its application range. The transmittance at 500 nm was recorded for 1.0 g/L iC13EOnS solutions containing different NaOH, NaCl, CaCl2, and MgCl2 concentrations, as shown in Figure 9a–d. The results show that with more EO, whether it is NaOH, NaCl, CaCl2, or MgCl2, the greater the concentration required to change the light transmittance, the better the alkali resistance and salt resistance. For ionic surfactant, when the product of its activity and counter ion activity is equal to the solubility product of the salt formed by the surfactant and counter ion, the salt formed begins to precipitate. When EO unit is included in the molecular structure, the solubility of the product can be increased, so the solubility product is high. When the surfactant activity in the solution is similar, the counter ion activity required for precipitation is greater, so the iC13EOnS with more EO number shows better alkali/salt tolerance (Figure 10). [42]
Catalytic performance of modified beta zeolite on the synthesis of styrene and xylene: a kinetic study
Published in Indian Chemical Engineer, 2020
Yashika Raparia, Gopinath Halder, RajKumar Arya, Sanghamitra Barman
During the characterisation of acidic sites in zeolite the amount of ammonia desorbing above a certain temperature is taken as the acid site concentration. With the help of NH3 desorption peak area the total number of acidic sites were estimated. First calibration was done with NH3, it gives one standard value. Then a linear correlation (from data calibration) was made between concentration and surface area (below the peak of NH3-desorpted). Then interpolating surface area data of real NH-3 desorption, total acidity of catalyst was estimated. Acidity and basicity were estimated and shown in the Table 1. Table 1 shows that with an increase in metal loading the BET surface area of zeolite beta decreases. This might be attributed to the partial dissolution of framework during impregnation of alkali salt. This is supported by the fact that the BET surface area decreases linearly as a result of the decrease in the crystallinity of zeolite beta framework.
Catalytic hydrothermal liquefaction of biomass with K2CO3 for production of gasification feedstock
Published in Biofuels, 2021
Flabianus Hardi, Erik Furusjö, Kawnish Kirtania, Akihisa Imai, Kentaro Umeki, Kunio Yoshikawa
The criteria for selection of alkali catalyst, which should be active in both processes – that it is widely available, inexpensive and environmentally benign – can be fulfilled by K2CO3. Many studies report that introduction of K2CO3 during HTL improved liquid product yield [7–10], while during gasification it enhanced gasification efficiency and produced hydrogen-rich gas by accelerating water-gas shift reaction [11,12]. Potassium is present in terrestrial plants as one of the major ash constituent [13–15]. Furthermore, K2CO3 represents biomass ash behavior [16]. Introduction of alkali salt leads to a preference for operating the HTL process in the subcritical water region, ensuring solubility [17].