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Tannery Wastewater
Published in Arun Kumar, Jay Shankar Singh, Microalgae in Waste Water Remediation, 2021
During tanning, there is a problem of the presence of excess acid existing in wet blue/semi-chrome leathers, which could hamper the following processes like dyeing, fat liquoring and retanning. To counteract this acid a neutralization process is required, in which the following chemicals such as sodium formate, sodium sulfite, sodium bicarbonate, ammonium bicarbonate, neutralizing syntan are usually applied. Further the degree of neutralization depends on the desired properties of the finished leathers.
Mechanism of Cyclopolymerization
Published in George B. Butler, Cyclopolymerization and Cyclocopolymerization, 2020
Solvolysis of 5-hexenyl p-nitrobenzenesulfonate in 98% formic acid containing sodium formate proceeds with participation of the olefinic bond at a rate which is about twice that of the formolysis of the hexyl ester.85 The product, after hydrolysis, consisted of 68% cyclohexanol and 26% hexenol. Formolysis of the p-nitrobenzenesulfonates of 4-pentenol and 6-hexenol proceeded with negligible double bond participation to give mainly the products of direct substitution.
The Isolation of Glycosaminoglycans from Fish Eyeballs and Their Potential Application
Published in Omari V. Mukbaniani, Tamara N. Tatrishvili, Marc J. M. Abadie, Science and Technology of Polymers and Advanced Materials, 2019
The solution of 1,9-dimethylmethylene blue (DMB) was prepared by dissolving 1.6g of DMB and mixing with 0.5ml of ethanol, 1.0g sodium formate and 1.0 mL of formic acid and then filled to 0.5 1 with distilled water [15]. The GAGs, such as HA and CS were identified by spectrophotometric method. The 2.5 mL of DMB dye solution was added to 250 µl of isolated from the eyeballs GAGs mixture. The wavenumber for the maximum absorbance was determined (HA at 520 cm−1, CS at 525 cm−1) and the standard curves for purchased HA and CS were made in their solutions concentration range 0.25–2%.
Study on wet oxidation process and mechanism for ethylene spent caustic
Published in Environmental Technology, 2022
Yuan Wei, Jun Zhao, ZongJian Liu, Lin Zhang, Qun Cui, HaiYan Wang
In this work, the concentration of formic acid is higher than the spent caustic and the concentration of acetic acid has no obvious change at the end of the reaction, which means that organic sulphides are mainly converted into formic acid. The acetic acid can partly be transferred into formic acid and further easily oxidized into CO2 and H2O. The results are the same as the reference García et al. [29]. They studied the humic acid (HA) oxidation process with reaction conditions of 180–220 °C and 6.5-9.5 MPa; the acetic acid and formic acid are detected by HPLC at the end of the reaction. They proposed HA was further oxidized into little molecular weight organic acids such as formic acid and acetic acid; the organic acids are then oxidized into CO2 and H2O. The oxidation pathway is proposed in formulas (12) and (13); formic acid and acetic acid generated by partial degradation can be slowly oxidized to form CO2 and H2O. Meanwhile, formic acid, acetic acid and sulphuric acid can continue to undergo acid–base neutralization reaction with NaOH solution to produce sodium formate, sodium acetate and sodium sulphate, as shown in formulas (14) to (16).
Effect of formic acid inflow on microbial properties of the anaerobic granular sludge in a UASB reactor
Published in Journal of Environmental Science and Health, Part A, 2022
Kazuaki Syutsubo, Yuma Miyaoka, Tsuyoshi Danshita, Yasuyuki Takemura, Masataka Aoki, Noriko Tomioka, Haruhiko Sumino, Takahiro Watari, Takashi Yamaguchi
In phase 2, inflow of formate caused a considerable increase in pH in the UASB reactor; therefore, to maintain the effluent at neutral pH, the synthetic wastewater was maintained at a pH of around 4 by mixing formic acid and sodium formate (Table 1). In addition, the concentration of sodium bicarbonate was reduced to 2,000 mg/L. As a result, the effluent pH remained at around 7.5 in phase 2, as well as in phase 1. For reference, the pH of the natural rubber processing wastewater is 4–5, which is suitable for methanogenic treatment. In terms of process performance, inflow of formate had no significant influence on COD removal efficiency. The average effluent total COD concentration decreased to 93 mgCOD/L as the effluent TSS concentration was reduced. As a result, COD removal efficiency reached 98.2% during phase 2. It should be noted that the degradation of formate caused a substantial increase in pH in the UASB reactor.
Preparation, characterization, and removal of nitrate from water using vacant polyoxometalate/TiO2 composites
Published in Environmental Technology, 2022
Lingsheng Wang, Weizhang Fu, Shujuan Sun, Huaihao Liu, Jinhua Wang, Wanzhen Zhong, Bin Ma
In the photocatalytic reaction of semiconductors, hole scavengers can irreversibly bind to holes on the surface of an irradiated semiconductor, preventing electrons and holes from recombining on the surface of a catalyst, thus increasing the lifetime of electrons. This, in turn, increases the efficiency of photocatalytic reduction. Hole scavengers include methanol, sodium formate, formic acid, EDTA, etc. SiW11/TiO2/Cu produces electron–hole pairs during UV irradiation, wherein the photogenerated electrons can be used for the reduction of NO3–N. The recombination of electron–hole pairs decreases the number of photogenerated electrons available to reduce NO3–N. The effect of hole scavenger type (formic acid, methanol, sodium formate, EDTA) on the photocatalytic degradation of NO3–N by SiW11/TiO2/Cu was investigated. As shown in Figure 8, for SiW11/TiO2/Cu, formic acid was the most effective hole scavenger for NO3–N removal, while methanol, sodium formate, and EDTA did not greatly improve the NO3–N removal rate. This was consistent with previous studies, which showed that formic acid readily adsorbed onto the photocatalyst surface, which resultantly decreased the reaction of free radicals with photogenerated holes following their formation. Methanol, sodium formate, and EDTA did not significantly adsorb onto the photocatalyst surface and, therefore, did not enhance the removal of holes [51–53].