Protocatechuic acid (PCA) is typically produced by microbial fermentation. Its separation from fermentation broth or aqueous waste streams is of great importance. This study aimed to recover PCA by a secondary amine namely di-n-octylamine (DOA). Three organic solvents, namely isobutyl methyl ketone, propyl acetate and linalool, were used with DOA. Important extraction parameters were optimised by response surface methodology. DOA/isobutyl methyl ketone system showed 95.84% extraction efficiency under the optimum conditions. The maximum E% of the DOA/propyl acetate system was 86.73%. The maximum E% of the DOA/linalool system was 81.71%. Additionally, a thermodynamic study was carried out, and the reactions were endothermic.

Protocatechuic acid (PCA) is a carboxylic acid of great interest since it has several pharmaceutical properties. PCA is either obtained by microbial fermentation or recovered from waste streams of food processing industries. In this study, PCA was separated from its aqueous solutions by a reactive extractant trioctylphosphine oxide (TOPO). Isobutanol, propyl acetate, and ethyl methyl ketone were used with TOPO in the organic phase. The operating parameters have been optimized by Box–Behnken design of response surface methodology. The maximum extraction efficiency of TOPO/isobutanol system was 98.91

cis,cis -Muconic acid is a high value-added fermentation product, which is used as a precursor for the synthesis of commercially important bulk chemicals. Therefore, its recovery from the fermentation broth is essential. In this study, the adsorptive removal of cis,cis -muconic acid has been examined for the first time. cis,cis -Muconic acid has been removed from its aqueous solution by Amberlite IRA-67, Amberlite XAD-4, Amberlite A-21, and activated carbon. The adsorption kinetic behavior of cis,cis -Muconic acid has been examined by kinetic models and best described by pseudo-second-order model. The distribution of the acid onto the adsorbents has been investigated by several two-parameter isotherm models. All the adsorbents were found to be quite successful at removing the acid because adsorption capacities reached up to 99 mg g −1 in a short time interval. After the kinetic study, it is revealed that 20 min of shaking was appropriate to remove the acid. The Biot numbers less than 100 indicated that external diffusion occurred predominantly on the adsorbent surface instead of internal diffusion. Central composite design of response surface methodology was used to optimize the important adsorption parameters, namely, acid concentration, adsorbent quantity, and temperature. The model predicted best results at 994.70 mg L −1 acid concentration, 0.08 g adsorbent quantity, and 300.2 K temperature for IRA-67; 994.70 mg L −1 acid concentration, 0.05 g adsorbent quantity, and 301.2 K temperature for XAD-4; 994.70 mg L −1 acid concentration, 0.08 g adsorbent quantity, and 300.2 K temperature for A-21; and 994.70 mg L −1 acid concentration, 0.08 g adsorbent quantity, and 299.2 K temperature for activated carbon.

This article seeks to study the consequences of the Nagorno–Karabakh war for Azerbaijan: thus analyzes findings on occupied territories, casualties, and damages of the war from economic, political, and social perspectives. The utmost brutality and atrocity of the overall conflict is memorized with Khojaly Massacre committed against Azerbaijani civilians on 26 February 1992. Hence, the article unveils evidences through the scrutiny of secondary data from academic sources, publications, and news materials published by international media. The particular focus of the study is concentrated on to what extend special plan was prepared deliberately for ethnic cleansing in Khojaly during the Nagorno–Karabakh war.