Textile effluent treatment employing yeast biomass and a new nanomagnetic biocomposite.

Fabric dyeing produces high amounts of wastewater containing organic and inorganic pollutants such as reactive dyes that are the most common textile dyes employed by the industry. Three vinylsulfonic reactive dyes, blue 19 (B-19), red 198 (R-198), and yellow 15 (Y-15), were removed from effluents of industrial-like dyeing processes employing three adsorbents: (1) magnetite nanoparticles (MNP), (2) yeast waste obtained after ß-glucan removal from yeast biomass (YW), and (3) nanomagnetic composite produced from YW and MNP (YW-MNP). The non-linear kinetic pseudo-second-order and two-stage models best explained the experimental phenomena for the majority of adsorbate:adsorbent systems. The theoretical isotherm models were fitted to experimental isotherms obtained from experiments conducted with appropriated dilutions of effluents, which have a specific condition, limited by the maximum dye concentration established by the dye recipe. Thus, the saturation of adsorbents was not reached for all adsorbate:adsorbent systems. In this way, the best conditional sorption capacities (SCcond) were obtained by YW (1.7, 2.3, and 2.5 g/kg for B-19, R-198, and Y-15, respectively). The SIPS model best described all dyes adsorbed by YW, while the D-R model best described the phenomena for MNP and YW-MNP.

Activated carbon production from industrial yeast residue to boost up circular bioeconomy.

This work aims to obtain activated carbon (AC) from yeast residue to boost up bioeconomy. In this way, carbon was prepared from yeast biomass produced by the ethanol industry and after beta-glucan extraction. Carbon was activated with CO2, water vapor, and a combination of both using an experimental design. The best conditions to produce AC were activation with CO2 for 30 min at 850 °C and CO2 flow of 0.09 L/min, set by experimental design and desirability function to optimize the yield, surface area, and microporosity. Thus, for physical activation with water vapor employing the optimized conditions, it was possible to achieve a yield of 56.6% (m/m) for AC with 1144 m2/g of surface area and mean micropore volume of 0.53 cm3/g. The maximum AC surface area reached 1616 ± 567 m2/g with a yield of 21 ± 1%. The prepared ACs were characterized by elemental analysis, X-ray diffractometry, infrared spectroscopy, thermogravimetry analysis, pHPZC, and potentiometric titration to determine the main functional groups of sorption sites. The carbon obtained from the desirability condition was used to remove dipyrone from synthetic aqueous effluent with an experimental sorption capacity of 88 ± 4 mg/g, being the phenomenon described by the Freundlich isotherm model.

Oil spill cleanup employing magnetite nanoparticles and yeast-based magnetic bionanocomposite.

Oil spill is a serious environmental concern, and alternatives to remove oils from water involving biosorbents associated to nanoparticles is an emerging subject. Magnetite nanoparticles (MNP) and yeast magnetic bionanocomposite (YB-MNP) composed by yeast biomass from the ethanol industry were produced, characterized, and tested to remove new motor oil (NMO), mixed used motor oil (MUMO) and Petroleum 28 °API (P28API) from water following the ASTM F726-12 method, which was adapted by insertion of a lyophilization step to ensure the accuracy of the gravimetric approach. Temperature, contact time, the type and the amount of the magnetic material were the parameters evaluated employing a fractional factorial design. It was observed the removal of 89.0 ±â€¯2.6% or 3522 ±â€¯118 g/kg (NMO) employing MNP; 69.1 ±â€¯6.2% or 2841 ±â€¯280 g/kg (MUMO) with YB-MNP; and 55.3 ±â€¯8.2% or 2157 ±â€¯281 g/kg (P28API) using MNP. The temperature was the most significant parameter in accordance with the Pareto's graphics (95% confidence) for all oil samples considered in this study as well as the two magnetic materials. Contact time and the interaction between the materials and temperature were also relevant. The D-Optimals designs showed that the NMO and P28API responded in a similar way for all evaluated parameters, while the uptake of MUMO was favored at higher temperatures. These behaviors demonstrate the influence of oil characteristics and the intermolecular forces between the oil molecules on the mechanism dragging process performed by the attraction between magnetite nanoparticles and a 0.7 T magnet. It was clear that this kind of experiment is predominantly a physic phenomenon which cannot be described as adsorption process.