New Proposal in a Biorefinery Context: Recovery of Acetic and Formic Acids by Adsorption on Hydrotalcites

Abstract

Acetic acid (AA) and formic acid (FA) are two of the major fermentation inhibitors found in hemicellulosic hydrolysates. Their removal, which is necessary for the use of hydrolysates as fermentation substrates, can be achieved by adsorption on hydrotalcites. This study aimed to assess the efficiency of hydrotalcites in removing AA and FA from aqueous solution. Kinetic, thermodynamic, and equilibrium experiments were conducted using hydrotalcites composed of 30, 63, or 70% MgO. Calcined hydrotalcites composed of 70 and 63% MgO (MG70c and MG63c) had the best kinetic performance, removing 97% of FA and 91% of AA. The adsorption process followed pseudo-first-order kinetics. The Boyd model showed that external mass transfer or a combination of intraparticle diffusion and external mass transfer controls the process. Adsorption equilibrium was evaluated at different temperatures (30, 40, 50, and 60 °C) using MG70c as an adsorbent. The Freundlich model provided the best fit to adsorption isotherms. Thermodynamic studies indicated that adsorption was spontaneous and endothermic in nature. The results confirmed the efficiency of MG70c in removing AA and FA from aqueous solution.

The use of anion exchange pigments to inhibit the filiform corrosion of zinc-aluminium-magnesium coated steel

“…weeks. The ability of HT to remove HAc from aqueous solution and displace carbonate as CO 2 has been demonstrated previously [39] and is related to the low pKa value (4.7) associated with HAc compared to carbonate and hydrogen carbonate anions [40]. It therefore seems plausible that HT acts to scavenge Acvia an anion exchange reaction (Equation 3), shown schematically in Figure 7.…”

“…One notable example is within the PVC industry, where it acts as a scavenger of HCl [31] and as a medical antacid [38]. Other work has demonstrated the ability of HT to remove carboxylic acids including acetic acid from aqueous solution [39,40]. This property also means that HTs are able to behave as exchangers (e.g.…”

Extractive Catalytic Oxidative Deoxygenation of Model Fuels Catalyzed by a Vanadium-Substituted Heteropolyacid and Molecular Oxygen

“…Again, the mass balance could be completely closed showing only small deviations of +3% with respect to the discrepancy between determined conversion in the organic phase via GC–MS and product quantification in the aqueous phase via HPLC and GC in the gas phase. Both acetic and formic acid should therefore be removed via nanofiltration or adsorption. , …”

Effects of thiol functionalization of a waste-derived activated carbon on the adsorption of sulfamethoxazole from water: Kinetic, equilibrium and thermodynamic studies

“…However, according to the t-Student test (t-test) for comparing the slope of the obtained regressions presented in Figure S6 (in SM), these are not significantly different at a 5% level, with the t experimental value (t exp ) being lower than the theoretical (or critical) t value (t crit ) [54] (Table S4, in SM). In any case, as for the E a standing between 8.4 and 83.7 kJ mol -1 , activated chemisorption, which involves stronger adsorption forces than physisorption, may be inferred [30,55]. With respect to the pre-exponential factor A,…”