Valorization of winemaking residues as biochar for removing Ni(II) from real industrial painting process effluent in a fixed-bed column.

In this work, the adsorption of nickel ions from a real effluent from a metal-mechanic industry was investigated in a fixed-bed column using biochar. Biochar was prepared from winemaking residues originating from the Beifiur® composting process. The use of wine industry residues as precursor materials for biochar production is established in biomass residue valorization using the existing logistics and the lowest possible number of manipulations and pre-treatments. The results found in the work showed that the optimal conditions for nickel adsorption in fixed-bed columns were bed height (Z) of 7 cm, initial nickel concentration (C0) of 1.5 mg L-1, and flow rate (Q) of 18 mL min-1. In this condition, the maximum adsorption capacity of the column was 0.452 mg g-1, the mass transfer zone (Zm) was 3.3 cm, the treated effluent volume (Veff) was 9.72 L, and the nickel removal (R) was 92.71%. The Yoon-Nelson and BDST dynamic models were suitable to represent the breakthrough curves of nickel adsorption. Finally, the fixed-bed column adsorption using biochar from winemaking residues proved to be a promising alternative for nickel removal from real industrial effluents.

Polishing of painting process effluents through adsorption with biochar from winemaking residues.

A real industrial effluent from the pre-treatment and painting processes was polished through adsorption using alternative biochar derived from grape pomace wastes. The biochar was produced in a pilot-scale plant from composted grape pomace. Biochar showed an equilibrium between acidic and basic groups on the surface. The presence of irregular cavities in the structure and mesopores was confirmed by analyzing N2 physisorption and SEM. Concerning the effluent, Ni and Zn were the main problematic elements. The adsorption isotherms and kinetics of Ni and Zn from the effluent using the biochar could be represented by the Henry, pseudo-first-order, and pseudo-second-order models, respectively. Adsorption equilibrium was reached within 60 min for Ni and Zn present in the real effluent. Besides, the adsorption process was endothermic, favorable, and spontaneous. These results demonstrate that Zn and Ni metals were successfully removed from the industrial effluent, presenting final concentration values within the limit of legislation for effluent disposal in agricultural soil.

Kinetic and thermodynamic study of enzymatic hydroesterification mechanism to fatty acid methyl esters synthesis.

Eversa® Transform 2.0 lipase used as biocatalyst to biodiesel (fatty acid methyl esters - FAME) synthesis has been the target of interesting studies due to its thermostability and cost-effectiveness. In these researches, data about reaction conditions that result in satisfactory yields were investigated. Nevertheless, kinetic and thermodynamic parameters considering this enzyme are scarce. This paper presents an estimation of kinetic and thermodynamic parameters for the Eversa® Transform 2.0-mediated hydroesterification to FAME synthesis. Kinetic studies were performed for different methanol, water and lipase loads in distinct temperatures. Parameters adjusted by the thermodynamic model indicate that the hydrolysis is decisive in the overall hydroesterification reaction rate and the esterification reaction is endothermic (ΔHe = 38.98 kJ/mol). Formation of enzymatic complexes is favored by increasing the temperature, especially the enzyme-methanol inhibition complex. Statistical analysis showed that the model was not overparameterized, and the small confidence interval indicated good reliability of the estimated parameters.