Use of Biochar Prepared from the Açaí Seed as Adsorbent for the Uptake of Catechol from Synthetic Effluents.

This work proposes a facile methodology for producing porous biochar material (ABC) from açaí kernel residue, produced by chemical impregnation with ZnCl2 (1:1) and pyrolysis at 650.0 °C. The characterization was achieved using several techniques, and the biochar material was employed as an adsorbent to remove catechol. The results show that ABC carbon has hydrophilic properties. The specific surface area and total pore volume are 1315 m2·g−1 and 0.7038 cm3·g−1, respectively. FTIR revealed the presence of oxygenated groups, which can influence catechol adsorption. The TGA/DTG indicated that the sample is thermally stable even at 580 °C. Adsorption studies showed that equilibrium was achieved in <50 min and the Avrami kinetic model best fits the experimental data, while Freundlich was observed to be the best-fitted isotherm model. Catechol adsorption on ABC biochar is governed by van der Waals forces and microporous and mesoporous filling mechanisms. The Qmax is 339.5 mg·g−1 (40 °C) with 98.36% removal of simulated effluent, showing that açaí kernel is excellent biomass to prepare good biochar that can be efficiently used to treat real industrial effluents.

Evaluation of efficiency and selectivity in the sorption process assisted by chemometric approaches: Removal of emerging contaminants from water.

This paper describes, by the first time, a chemometric approach that combines a simple set of the UV-Vis spectra and partial least square regression (PLSR) for measuring the removal of five pharmaceuticals present in simulated hospital effluents by sorption using activated carbon. The use of multivariate calibration allowed the quantification of the remaining concentrations of the studied drugs present in a complex mixture with high accuracy, avoiding the need for the use of sophisticated methodologies based on chromatography. Isothermal sorption studies were performed on single-component solutions containing amoxicillin, paracetamol, propranolol, sodium diclofenac, or tetracycline as well as on a solution containing a mixture of all these 5 compounds. The isotherm data obtained were fitted to the Langmuir, Freundlich and Liu models. It was observed that for each pharmaceutical, the maximum sorption capacity of the activated carbon was higher for the single component than in the mixture. It was observed that the removal of paracetamol, propranolol, and tetracycline, the removal was complete (100%) and for amoxicillin and sodium diclofenac it was at least 92.71 ±â€¯3.15% and 91.82 ±â€¯0.95% respectively, indicating that the avocado seed activated carbon is an adsorbent with high sorption capacity that can remove five pharmaceuticals from simulated hospital effluents.

Synthesis of grafted natural pozzolan with 3-aminopropyltriethoxysilane: preparation, characterization, and application for removal of Brilliant Green 1 and Reactive Black 5 from aqueous solutions.

Natural pozzolan is an amorphous silicate-based material of volcanic origin. In this work, the natural pozzolan was modified by using 3-aminopropyltriethoxysilane (APTES) as a grafting agent. This material was characterized by pHpzc, N2 adsorption/desorption curves, FTIR, TGA/DTG, DRUV, SEM, and elementary analysis. The functionalized materials were used for the removal of Reactive Black 5 (RB-5) and Brilliant Green 1 (BG-1) dyes from aqueous solutions using batch-contact adsorption. The characterization of modified pozzolan by FTIR, TGA/DTG, BET, and DRUV-vis revealed the effectiveness of grafting of amine functional group on pozzolan structure. The kinetic adsorption data were better fitted with general order for both dyes while for equilibrium models were better fitted by the Liu isotherm model. The maximum sorption capacities Q max (at 50 °C) obtained with the modified pozzolan were 350.6 and 300.9 mg g-1 for BG-1 and RB-5, at pH 9.0 and 2.0, respectively. The thermodynamic parameters show that the removal of dyes was spontaneous and endothermic. The modified material was also tested for the treatment of simulated dye house effluents showing very high efficiency.