scholarly journals Effect of acidity level of substrate by lime water and acetic acid addition on biogas production

2019 ◽  
Author(s):  
Hendry Sakke Tira ◽  
Yesung Allo Padang ◽  
Supriadi
Keyword(s):  
Acetic Acid ◽  
Biogas Production ◽  
Acid Addition ◽  
Lime Water ◽  
Acidity Level

Effect of sulfate on anaerobic processes fed with dual substrates

1995 ◽  
Vol 31 (9) ◽  
pp. 101-107 ◽  
Author(s):  
Chongchin Polprasert ◽  
Charles N. Haas
Keyword(s):  
Acetic Acid ◽  
Sulfate Reduction ◽  
Mixed Culture ◽  
Biogas Production ◽  
Cod Removal ◽  
Methane Formation ◽  
Batch Mode ◽  
Sulfate Reducing ◽  
Anaerobic Reactors ◽  
Optimal Feed

Anaerobic reactors were operated in a semi-batch mode and fed with the dual substrates glucose (G) plus acetic acid (Ac) as primary organic sources to study the effect of sulfate on COD oxidation. With glucose, COD removal by methane formation was seriously inhibited, resulting in COD accumulation in the reactor. Although acetic acid can be consumed by some sulfate-reducing species, it was not a major substrate for sulfate reduction, but was largely responsible for methane formation in the anaerobic mixed culture used in this study. With dual substrates, extreme inhibition of methanogenesis did not occur as did with glucose alone. Instead, methanogens were found to work in harmony with acid formers as well as sulfate reducers to oxidise COD. Interestingly, from 12-hour monitoring, increased G/Ac COD ratios decreased COD removal rates as well as biogas production, but resulted in higher sulfate reduction. This suggests that there should be an optimal feed G/Ac COD ratio, for which removal of both organics could be maximised.

scholarly journals Does Acid Addition Improve Liquid Hot Water Pretreatment of Lignocellulosic Biomass towards Biohydrogen and Biogas Production?

2020 ◽  
Vol 12 (21) ◽  
pp. 8935 ◽  
Author(s):  
George Dimitrellos ◽  
Gerasimos Lyberatos ◽  
Georgia Antonopoulou
Keyword(s):  
Lignocellulosic Biomass ◽  
Biogas Production ◽  
Hot Water ◽  
Liquid Hot Water ◽  
Acid Addition ◽  
Water Pretreatment ◽  
Inhibitory Compounds ◽  
Production Of Hydrogen ◽  
Potential Inhibitors ◽  
Hot Water Pretreatment

The effect of liquid hot water (LHW) pretreatment with or without acid addition (A-LHW) on the production of hydrogen—through dark fermentation (DF)—and methane—through anaerobic digestion (AD)—using three different lignocellulosic biomass types (sunflower straw (SS), grass lawn (GL), and poplar sawdust (PS)) was investigated. Both pretreatment methods led to hemicellulose degradation, but A-LHW resulted in the release of more potential inhibitors (furans and acids) than the LHW pretreatment. Biological hydrogen production (BHP) of the cellulose-rich solid fractions obtained after LHW and A-LHW pretreatment was enhanced compared to the untreated substrates. Due to the release of inhibitory compounds, LHW pretreatment led to higher biochemical methane potential (BMP) than A-LHW pretreatment when both separated fractions (liquid and solid) obtained after pretreatments were used for AD. The recovered energy in the form of methane with LHW pretreatment was 8.4, 12.5, and 7.5 MJ/kg total solids (TS) for SS, GL, and PS, respectively.

scholarly journals Aromatic glyoxalimines in criss-cross cycloaddition reactions

2004 ◽  
Vol 2 (1) ◽  
pp. 220-233 ◽  
Author(s):  
Jiří Verner ◽  
Milan Potáček
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Cycloaddition Reactions ◽  
Acid Addition

AbstractAromatic 1,4-diazabuta-1,3-dienes in glacial acetic acid with thiocyanates produce via criss-cross cycloaddition reactions the corresponding perhydroimidazo[4,5-d]imidazole-2,5-dithiones. When a mixture of thiocyanate and cyanate in a proper ratio was reacted together, nonsymmetrical 5-thioxo-perhydroimidazo[4,5-d]imidazole-2-ones were isolated. With cyanates substituted aromatic 1,4-diazabuta-1,3-dienes afforded product of acetic acid addition to primary formed 1,3-dipole intermediate 5-(4-substituted phenylamino)-3-(4-substituted phenyl)-2-oxoimidazolidin-4-yl acetate.

Effect of Acetic Acid Addition on Decomposition of Xylose in Supercritical Water

2018 ◽  
Vol 32 (2) ◽  
pp. 1754-1760 ◽  
Author(s):  
Tanawan Chalermsaktrakul ◽  
Yukihiko Matsumura
Keyword(s):  
Acetic Acid ◽  
Supercritical Water ◽  
Acid Addition

scholarly journals INFLUENCE OF ADDITIVES OF ACID ON STAGE OF TRANSFORMATIONS OF 4-NITRO-2'-HYDROXY-5'-METHYLASOBENZENE ON SKELETONIC NICKEL IN WATER SOLUTION OF 2-PROPANOL

2020 ◽  
Vol 63 (7) ◽  
pp. 41-47
Author(s):  
Hoang Anh ◽  
Olga V. Lefedova ◽  
Alexandra.V. Belova
Keyword(s):  
Aqueous Solution ◽  
Acetic Acid ◽  
Maximum Yield ◽  
Bulk Solution ◽  
Skeletal Nickel ◽  
Acid Addition ◽  
Starting Compound ◽  
Conversion Rates ◽  
Azo Group ◽  
Neutral Aqueous Solution

The article is devoted to the analysis of the reaction kinetics of hydrogenation of 4-nitro-2'-hydroxy-5'-methylazobenzene in an aqueous solution of 2-propanol with acetic acid addition on skeletal nickel at different initial quantity of the starting compound. Clarification of the sequence of transformations of compounds containing several reactive groups, and the development of approaches to controlling the selectivity of processes with their participation is a practically significant task. According to the data obtained, at both low and high initial concentrations the hydrogenation of 4-nitro-2'-hydroxy-5'-methylazobenzene on skeletal nickel in a 2-propanol aqueous solution-0.01 M CH3COOH solvent proceeds in two parallel directions. The largest contribution in the first phase of the reaction is made by the azo group conversion of the starting compound, in contrast to the reaction in an aqueous solution of 2-propanol without acid addition. An increase in the initial quantity of the hydrogenated compound above its solubility limit leads to an increase in the rate of conversion of the azo group in 4-nitro- and 2-amino-2'-hydroxy-5'-methylazobenzene. Consequently, optimum quantity of 4-nitroaniline and 2-amino-2'-hydroxy-5'-methylazobenzene in the bulk solution during hydrogenation of the specified quantity of 4-nitro-2'-hydroxy-5'-methylazobenzene practically didn’t change, in contradiction to the hydrogenation on skeletal nickel in a neutral aqueous solution of 2-propanol. In a neutral aqueous solution of 2-propanol, when passing to high concentrations of the hydrogenated compound, the maximum yield of 4-nitroaniline increases twice as long the better, while as 4-amino-2'-hydroxy-5'-methylazobenzene, is reduced conversely. The results obtained do not contradict the concept of a parallel-sequential scheme for the conversion of 4-nitro-2'-hydroxy-5'-methylazobenzene. One of the directions involves the conversion of 4-nitro-2'-hydroxy-5'-methylazobenzene through 4-nitroaniline and 2-amino-4-methylphenol due to the hydrogenation of the azo group, and the second is the conversion of 4-nitro-2'-hydroxy-5'- methylazobenzene via 4-amino-2'-hydroxy-5'-methylazobenzene by reduction of the nitro group. At the end of the reaction, all the intermediate compounds are reduced to 2-amino-4-methylphenol and 1,4-phenylenediamine. When acetic acid is introduced into the composition of the neutral solvent 2-propanol-water, the contribution of the direction that ensures the formation of 4-nitroaniline and 2-amino-4-methylphenol to the overall reaction rate increases. An increase in the initial amount of 4-nitro-2′-hydroxy-5′-methyl-azobenzene leads to an increase in the rate of conversion of the azo group in the starting compound and to a decrease in the rate of conversion of 4-amino-2′-hydroxy-5′-methylazobenzene. The effect of the acid on the change in the conversion rates of nitro and azo groups to 4-nitro-2′-hydroxy-5′-methylazobenzene does not contradict the previously obtained results for the hydrogenation of its analogue, 2-nitro-2′-hydroxy-5-methylazobenzene, as well as individual compounds containing a nitro and azo group.

scholarly journals The Toxic Effect of Herbicidal Ionic Liquids on Biogas-Producing Microbial Community

2019 ◽  
Vol 16 (6) ◽  
pp. 916 ◽  
Author(s):  
Jakub Czarny ◽  
Agnieszka Piotrowska-Cyplik ◽  
Andrzej Lewicki ◽  
Agnieszka Zgoła-Grześkowiak ◽  
Łukasz Wolko ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Ionic Liquids ◽  
Production Efficiency ◽  
Biogas Production ◽  
Bacterial Biomass ◽  
Operational Taxonomic Units ◽  
Supernatant Liquid ◽  
Sequencing Method ◽  
Miseq Platform ◽  
Dichlorophenoxy Acetic Acid

The aim of the study was to evaluate the effect of herbicidal ionic liquids on the population changes of microorganisms used in a batch anaerobic digester. The influence of the following ionic liquids: benzalkonium (2,4-dichlorophenoxy)acetate (BA)(2,4-D), benzalkonium (4-chloro-2-methylphenoxy)acetate (BA)(MCPA), didecyldimethylammonium (2,4-dichlorophenoxy)acetate (DDA)(2,4-D), didecyldimethylammonium (4-chloro-2-methylphenoxy)acetate (DDA)(MCPA), as well as reference herbicides (4-chloro-2-methylphenoxy)acetic acid (MCPA) and (2,4-dichlorophenoxy)acetic acid (2,4-D) in the form of sodium salts on biogas production efficiency was investigated. The effective concentration (EC50) values were determined for all tested compounds. (MCPA)− was the most toxic, with an EC50 value of 38.6–41.2 mg/L. The EC50 for 2,4-D was 55.7–59.8 mg/L. The addition of the test substances resulted in changes of the population structure of the microbiota which formed the fermentation pulp. The research was based on 16S rDNA analysis with the use of the Next Generation Sequencing method and the MiSeq platform (Illumina, San Diego, CA, USA). There was a significant decrease in bacteria belonging to Firmicutes and Archaea belonging to Euryarchaeota. A significant decrease of the biodiversity of the methane fermentation microbiota was also established, which was expressed by the decrease of the operational taxonomic units (OTUs) and the value of Shannon’s entropy. In order to determine the functional potential of bacterial metapopulations based on the 16SrDNAprofile, the PICRUSt(Phylogenetic Investigation of Communities by Reconstruction of Unobserved States)tool was used, which allowed to determine the gene potency of microorganisms and their ability to biodegrade the herbicides. In the framework of the conducted analysis, no key genes related to the biodegradation of MCPA or 2,4-D were found, and the observed decrease of their content in the supernatant liquid was caused by their sorption on bacterial biomass.

scholarly journals Improving Electrochromic Cycle Life of Prussian Blue by Acid Addition to the Electrolyte

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 28 ◽  
Author(s):  
ZiTong Li ◽  
YunHui Tang ◽  
KaiLing Zhou ◽  
Hao Wang ◽  
Hui Yan
Keyword(s):  
Acetic Acid ◽  
Prussian Blue ◽  
Cycle Life ◽  
Optical Modulation ◽  
Cyclic Stability ◽  
Solution Ph ◽  
Ph Values ◽  
Acid Addition ◽  
Improved Stability

In this study, we examined the cyclic stability of Prussian blue (PB) films in electrolytes with acid. The cyclic stabilities of the PB films were investigated in K+ based electrolytes with different values of solution pH. The acidified KCl solution can significantly improve the durability of the film. Among the three pH values tested, the KCl solutions (pH = 2.15 and pH = 3.03) showed better performance. Furthermore, we investigated the cyclic stabilities of the PB films in LiClO4/PC electrolyte containing different acids. We found that the cyclic stability of PB film was significantly improved when a small amount of acetic acid was dissolved in LiClO4/PC electrolyte. The PB film exhibited stable optical modulation after up to 20,000 cycles in LiClO4/PC electrolyte containing acetic acid—a much higher result than those of some literatures. This suggests that the addition of acetic acid to LiClO4/PC electrolyte can promote the development of PB-based devices with improved stability.

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