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Fundamentals of Electric Capacitors
Published in Aiping Yu, Victor Chabot, Jiujun Zhang, Electrochemical Supercapacitors for Energy Storage and Delivery, 2017
Aiping Yu, Victor Chabot, Jiujun Zhang
A typical non-aqueous-based liquid electrolyte is generally composed of a weak acid, a salt derived from a weak acid, a solvent, an optional thickening agent, and other additives. The electrolyte is usually soaked into an electrode separator that serves as the dielectric. Weak acids are organic and include glacial acetic acid, lactic acid, propionic acid, butyric acid, crotonic acid, acrylic acid, phenol, and cresol. The salts are ammonium or metal salts of organic acids, including ammonium acetate, ammonium citrate, aluminum acetate, calcium lactate, and ammonium oxalate; or weak inorganic acids such as sodium perborate and trisodium phosphate. Electrolyte solvents are based on alkanolamines (monoethanolamine, diethanolamine, and triethanolamine) or polyols (diethylene glycol, and glycerol).
Environmental Problems in Soil and Groundwater Induced by Acid Rain and Management Strategies in China
Published in P.M. Huang, I.K. Iskandar, M. Chino, T.B. Goh, P.H. Hsu, D.W. Oscarson, L.M. Shuman, Soils and Groundwater Pollution and Remediation, 2020
Guoliang Ji, Jinghua Wang, Xiaonian Zhang
The pH at which half of the cation-exchange sites is occupied by base cations may be called the “half-neutralization pH,” because this is equivalent to a weak acid half-neutralized by a base. This pH is equivalent to the pKa value of the weak acid. For the three soil colloids examined, the values are 7.6, 6.7, and 6.5, respectively, reflecting the difference in their acid strength. For a given soil, this pH is affected by the kind of the base cations. If the cation species is calcium instead of sodium, this pH would be lower than that shown in Figure 8.3. At this pH, the buffering strength of the soil is the strongest, as can also be seen in the figure.
Capillary Electrophoresis
Published in Grinberg Nelu, Rodriguez Sonia, Ewing’s Analytical Instrumentation Handbook, Fourth Edition, 2019
The buffer solution should resist pH change on dilution and addition of small amounts of acids and bases. Concentrated buffer solutions do this well but can be too conductive for use in CE. The buffering capacity of a weak acid or weak base is limited to ±1 pH unit of its pKa. CE operation outside of this range requires frequent buffer replacement to avoid pH changes [11]. Aromatic buffer constituents such as phthalates should be avoided, if possible, because of their strong UV chromophore. In addition, strongly absorbing components such as carrier ampholytes prevent the use of the low UV detector wavelengths.
A Review on Green Method of Extraction and Recovery of Energy Critical Element Cobalt from Spent Lithium-Ion Batteries (LIBs)
Published in Mineral Processing and Extractive Metallurgy Review, 2023
Archita Mohanty, Niharbala Devi
Acetic acid is a weak acid with one carboxylic group and a low ionization constant (pKa = 4.76). Because acetic and lactic acids are weak and dissociate in a single step, there have been a few studies on recycling used LIBs with these acids. It has been stated that in the presence of acetic acid, without the use of reducing agent and solid-to-liquid ratio (S/L) of 30 g L−1, there is a maximum recovery of 72% lithium and about 30% cobalt. And upon increasing the acid concentration from 2 mol/L to 6 mol/L, the leaching efficacy decreased to 19% and 67% respectively. This may be due to the release of only one proton (H+) for each acetic acid (Golmohammadzadeh, Rashchi and Vahidi 2017). In a report using lactic acid in the leaching process, results showed high recovery of 97.7% lithium, 98.9% cobalt, 98.2% nickel, and 98.4% magnesium at optimum conditions of 1.5 mol/L lactic acid, 20 g L−1 S/L, 70°C temperature,0.5 vol. % H2O2 concentration, and 20 min reaction time (Li et al. 2017).
Alleviation of boron toxicity in plants: Mechanisms and approaches
Published in Critical Reviews in Environmental Science and Technology, 2021
Tianwei Hua, Rui Zhang, Hongwen Sun, Chunguang Liu
The pH of the soil solution is known to affect B adsorption and its availability to plants (Smith et al., 2013). At neutral soil pH, the most plentiful form of B is a soluble nonionized form, boric acid (H3BO3), which is considered as the available form for plants (Güneş et al., 1999). Boric acid is a weak acid with a low acid dissociation constant and high pK value. At high pH, about ten percent of H3BO3 exists in the form of tetraborate anion, B(OH)4−, which is easily adsorbed by clay minerals (Hutchinson & Viets, 1969). With the increase of soil pH, more B(OH)4− is adsorbed and the decrease of water-soluble B(OH)4− induces depletion of H3BO3. To reduce soil available B (H3BO3), an efficient approach is to increase soil pH by liming (Gupta & Macleod, 1981; Lehto & Mälkönen, 1994; Tsadilas et al., 2005). Besides increasing soil pH, liming can also increase calcium carbonate, which acts as an important B adsorbing surface in calcareous soils (Goldberg, 1997). As reported by Tsadilas et al. (2005), liming significantly increased soil pH, which is negatively correlated with soil available B and tissue B in tobacco leaves.
Biosorption of direct textile dye Congo red by Bacillus subtilis HAU-KK01
Published in Bioremediation Journal, 2019
Khan Mohd. Sarim, Kamlesh Kukreja, Ikbal Shah, Chetan K. Choudhary
After immobilization, bacterial isolate exhibited efficient percent of decolorization as compared to free cells. Batch biosorption study was carried out by immobilizing cells of B. subtilis HAU-KK01 with 3 and 5 g of biobeads mass suspended into 250 ml Erlenmeyer flasks containing 100 ml of suspension of 100 mg/l Congo red dye. The flasks were kept in different shake conditions (i.e. 0, 50, 100 and 150 rpm) for 10 h in an orbital shaker at room temperature. Sample from each flask was withdrawn at 2 h intervals, biomass was harvested by centrifugation at 6000 rpm at 4 °C for 15 min and analyzed for dye biosorption at 495 nm using spectrophotometer (Systronic 106). The amount of dye adsorbed on the surface of biobeads is increased when time proceeds in experiment. Bacterial isolate TS-1 efficiently (84.5%) decolorized Congo red dye at 50 rpm on orbital shaker. While at 0 and 100 rpm dye decolorization was 45.9 and 69.3%, respectively, which suggested that decolorization by immobilized B. subtilis HAU-KK01 needs mild agitation while higher agitation causes reduction in decolorization potential of bacterium might be due to disintegration of biobeads. Figure 8 represents the potential of immobilized cells over free cells showed higher decolorization with two biobeads per ml. Sodium hydroxide and sulfuric acid (1 M) did not show any desorption but weak acid, like acetic acid (5 M) solubilized about 86.24% of CR from the spent adsorbent.