RESUMEN
This study aimed to examine sorption effectiveness of cationic dyes: Basic Red 46 (BR46) and Basic Violet 10 (BV10) onto spent coffee ground (CG) and spent green tea leaves (GTL). The scope of the study included, i.a.: sorbent FTIR spectra analysis, determination of pH effect on dye sorption effectiveness, analysis of dye sorption kinetics, and determination of maximal sorption capacity of the sorbents. The effectiveness of BR46 sorption on the sorbents tested was the highest at pH 6 and that of BV10 at pH 3. Both sorbents caused changes in solution pH during the sorption process, due to the system tending to reach the pH value approximating the pHZPC (pHPZC = 7.55 for CG and pHPZC = 7.05 for GTL). The time needed to reach BR46 and BV10 sorption equilibrium onto CG and GTL ranged from 180 to 240 min. The intramolecular diffusion model demonstrated that the sorption of cationic dyes onto CG and GTL proceeded in three phases differing in the intensity and duration. The maximal sorption capacity of CG reached 179.4 mg/g for BR46 and 59.3 mg/g for BV10. The sorption capacity of GTL was lower and reached 58.0 mg/g for BR46 and 26.7 mg/g for BV10.
RESUMEN
In order to be able to permanently settle other celestial bodies, it is necessary to create an efficient and closed life support system. Such a system will allow high autonomy and significantly reduce operating costs in a future colony. Grey water is a major waste stream in terms of the water volume generated by colonists, and its reuse is necessary. One possibility is to reuse it in aeroponic cultivation without treatment, which will in turn reduce its transported mass. The article focuses on water, carbon and other elements (N, P, K, Ca, Mg, Na) that are included in the mass balance of part of a life support system containing the aeroponic cultivation of lettuce that is supplied with clean water and water contaminated with one surfactant, crewmembers and a urine nitrification reactor. Three surfactants (Sodium Laureth Sulfate (SLES), Sodium Dodecylbenzene Sulfonate (SDBS), Sodium Methyl Cocoyl Taurate (SMCT)) in two concentrations, reflecting concentrated and diluted grey water, were tested. The growth of lettuce exposed to low concentrations (ca. 0.07 g·L-1) of surfactants has a moderate (SLES, SMCT) or no (SDBS) impact on the mass of grown plant. Exposition to high concentrations (>1.0 g·L-1) led to the complete failure of cultivation (SDBS, SMCT) or to very limited growth (SLES). In all cases, exposition to surfactants in low concentrations causes differences in the mineral composition of lettuce. In most cases, crops cultivated on water containing surfactants were characterized by a decreased harvest index (the ratio of edible biomass to total biomass). For the most cultivations the relative mass balances of water, C, N, P and K were generally unaffected by surfactants, while for Ca, Mg and Na, noticeable differences occurred. The data provided in the paper gives clues about which surfactant could be used in a future extraterrestrial colony.