Extractive separation of 4- hydroxybenzoic acid from aqueous solution using nontoxic and conventional solvents

2021 ◽  
Vol 36 ◽  
pp. 100782
Author(s):  
Anuradha Nanewar Joshi ◽  
Anil Kumar Chandrakar ◽  
Kailas L. Wasewar
Keyword(s):  
Aqueous Solution ◽  
Hydroxybenzoic Acid ◽  
Extractive Separation

scholarly journals Application of free and immobilized laccase for removal and detoxification of fluoroquinolones from aqueous solution

2020 ◽  
Keyword(s):  
Aqueous Solution ◽  
Trametes Versicolor ◽  
Storage Stability ◽  
Hydroxybenzoic Acid ◽  
Bacterial Strains ◽  
Covalent Bonds ◽  
Immobilized Laccase ◽  
And Storage

<p>Laccase from Trametes versicolor was immobilized by covalent bonds formation on CPC silica carriers. Elimination of two floroqinolone (FQ); enrofloxacine (ENR) and flumequine (FLU) using laccase in both free and immobilized form in the absence and presence of 1-hydroxybenzotriazole (HBT) and 4-Hydroxybenzoic acid (HBA) as mediators was investigated. Temperature, pH and storage stability of immobilized laccase was significantly improved compare to free laccase. In the absence of a laccase mediator, the initial concentrations of 50 mg L–1 of ENR and FLU decreased by 19 % and 28 %, respectively, after 6 h treatment using the immobilized laccase, while, the removal percentages were increased to 98 % and 96 %, respectively, when the immobilized laccase was used in presence of HBT. Whereas, the removal percentages of ENR and FLU were increased to 97 % and 88 %, respectively, when the immobilized laccase was used in presence of HBA. After twenty runs of the enzymatic elimination (laccase-HBT system) of ENR and FLU, the immobilized laccase exhibited the relative removal of 17.63 % and 15.62 %, respectively. The results of microtoxicity test (growth inhabitation percentage of six bacterial strains) showed a significant decrease in toxicity of the laccase-treated ENR and FLU solution.</p>

Destruction of EDTA by Bimetallic Al-Fe/O2 Process under Aqueous Room Temperature and Pressure Conditions

2013 ◽  
Vol 800 ◽  
pp. 555-559
Author(s):  
Xin Liu ◽  
Jin Hong Fan ◽  
Lu Ming Ma
Keyword(s):  
Aqueous Solution ◽  
Benzoic Acid ◽  
Removal Efficiency ◽  
Room Temperature ◽  
Ethylenediaminetetraacetic Acid ◽  
Oxidative Degradation ◽  
Hydroxybenzoic Acid ◽  
Mass Ratio ◽  
Initial Ph ◽  
Temperature And Pressure

Oxidative degradation of ethylenediaminetetraacetic acid (EDTA) in aqueous solution at room temperature and pressure by the bimetallic Al-Fe/O2 process, which was verified by the addition of benzoic acid as ·OH scavenger and the detection of para-hydroxybenzoic acid, was investigated. The results showed that the removal efficiency of EDTA, TOC and TN could be about 98%, 77.5% and 43% respectively after 3h reaction when the initial pH was 5. The effects of initial pH, concentration of EDTA, mass ratio of Al0 and Fe0 and Al-Fe loading were also investigated. Significantly, the bimetallic Al-Fe process exhibited higher reactivity than monometallic Fe0/Al0 process for the degradation of EDTA when the mass ratio of Al0 and Fe0 ranged from 0.11 to 2.97.

Energetics of the encapsulation of o-, m-, and p-hydroxybenzoic acids by β-cyclodextrin and its methylated and hydroxypropylated derivatives in aqueous solution

1999 ◽  
Vol 77 (3) ◽  
pp. 348-355 ◽  
Author(s):  
Elena Junquera ◽  
Valentin G Baonza ◽  
Emilio Aicart
Keyword(s):  
Aqueous Solution ◽  
Inclusion Complex ◽  
Aqueous Solutions ◽  
Inclusion Complexes ◽  
Binding Constant ◽  
Substituent Effect ◽  
Binding Constants ◽  
Hydroxybenzoic Acid ◽  
Guest Molecules ◽  
Hydroxybenzoic Acids

A fully computerized potentiometric technique has been used to analyze the energetics of the encapsulation of o-, m-, and p-hydroxybenzoic acids by β-cyclodextrin (β-CD) and (or) two of its most used derivatives: 2,6-di-O-methyl-β-cyclodextrin (DIMEB) and hydroxypropyl-β-cyclodextrin (HPBCD). The study has been carried out by measuring the pH of aqueous solutions of the three hydroxyacids in the absence of cyclodextrin at 25°C, and in the presence of cyclodextrin at several temperatures ranging from 15 to 40°C, keeping constant the concentration of the guest. The dissociation constant of the acids and the binding constants of the inclusion complexes formed have been simultaneously determined at all the temperatures by using a model previously derived by us. The carboxylic forms have been found to bind the CD with higher affinities than the carboxylate partners do, irrespective of the temperature, the cyclodextrin used, and the position of the substituents on the guest molecules. The formation of the inclusion complexes studied in this work has been found to be enthalpy driven, with a favorable enthalpic term dominant over an unfavorable entropic one. The effect of the substituents of both guest and host molecules on the thermodynamics of the inclusion processes has been analyzed. Key words: binding constant, β-cyclodextrin, hydroxybenzoic acid, inclusion complex, substituent effect.

Comparison of the degradation of p-hydroxybenzoic acid in aqueous solution by several oxidation processes

Chemosphere ◽  
2001 ◽  
Vol 42 (4) ◽  
pp. 351-359 ◽  
Author(s):  
Jesus Beltran-Heredia ◽  
Joaquin Torregrosa ◽  
Joaquin R. Dominguez ◽  
Jose A. Peres
Keyword(s):  
Aqueous Solution ◽  
Hydroxybenzoic Acid ◽  
Oxidation Processes
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