Sorption of cationic dyes from aqueous solutions by moss Rhytidiadelphus squarrosus: Kinetics and equilibrium studies

With the aim to investigate sorption properties of natural sorbent prepared from moss Rhytidiadelphus squarrosus we elucidated biosorption of cationic dyes Malachite green (BG4), Auramine O (BY2) and Thioflavine T (BY1) from aqueous solutions. The removal of dyes by moss biosorbent was found to be rapid at an initial stage and the equilibrium was reached within 1-2 hours. The pseudo-n-order kinetic model was successfully applied to the kinetic data and the order of adsorption reaction was calculated in the range from 1.7 to 2.6. The value of rate constant kn' ranged from 0.001 to 0.039 [min-1]/[μmol/g]1-n. The equilibrium data were fitted to the adsorption isotherms. The Freundlich isotherm was found to represent the measured sorption data of BG4, BY1 and BY2 well. The maximum sorption capacities of moss biomass from single dye solutions calculated by Langmuir equation were 354 μmol/g for BG4, 310 μmol/g for BY1 and 382 μmol/g for BY2. These results showed that the prepared biomass presents low-cost, natural and easy available sorbent which may be potentially used for removal of dyes from environment and also may be an alternative to more costly materials such as activated carbon.

Biosorption of cationic dyes BY1, BY2 and BG4 by moss Rhytidiadelphus squarrosus from binary solutions

A biosorbent prepared from moss Rhytidiadelphus squarrosus biomass was used for biosorption of cationic dyes – Malachite green (BG4), Auramine O (BY2) and Thioflavine T (BY1) from binary aqueous solutions. Sorption data obtained at non-equilibrium conditions were analyzed by Sheindorf-Rebuhn-Sheintuch (SRS) equation (competitive model for binary systems derived from Freundlich isotherm) and extended model of Freundlich isotherm. Following the comparison of coefficient of determination values (R2) as well as values of root mean squared error (RMSE), the extended model of Freundlich isotherm was more suitable for description of investigated binary systems BG4-BY1 (R2 BG4 = 0.983, R2 BY1 = 0.993) and BG4-BY2 (R2 BG4 = 0.976, R2 BY2 = 0.995). The competition coefficients aij, obtained from SRS model can be considered as a way to quantify mutual competitive interactions. The competition coefficients indicated that the presence of BY1 in binary system decreased the sorption of BG4 (aBY1,BG4 = 0.835) while presence of BG4 (aBG4,BY1 = 0.208) has less pronounced competitive effect on the sorption of BY1 onto biosorbent. Competition coefficients obtained for binary system BY1-BG4 indicate that BG4 (aBG4,BY2 = 0.186) was more significantly affected by the presence of BY2 (aBY2,BG4 = 1.167). Finally, equations used in this work were represented by the three-imensional biosorption isotherm surfaces.

Magnetically Functionalized Moss Biomass as Biosorbent for Efficient Co2+ Ions and Thioflavin T Removal

Microwave synthesized iron oxide nanoparticles and microparticles were used to prepare a magnetically responsive biosorbent from Rhytidiadelphus squarrosus moss for the rapid and efficient removal of Co2+ ions and thioflavin T (TT). The biocomposite was extensively characterized using Fourier transformed infrared (FTIR), XRD, SEM, and EDX techniques. The magnetic biocomposite showed very good adsorption properties toward Co2+ ions and TT e.g., rapid kinetics, high adsorption capacity (218 μmol g−1 for Co and 483 μmol g−1 for TT), fast magnetic separation, and good reusability in four successive adsorption–desorption cycles. Besides the electrostatic attraction between the oxygen functional moieties of the biomass surface and both Co2+ and TT ions, synergistic interaction with the –FeOH groups of iron oxides also participates in adsorption. The obtained results indicate that the magnetically responsive biocomposite can be a suitable, easily separable, and recyclable biosorbent for water purification.

ГОДИЧНЫЕ ПРИРОСТЫ, СТРОЕНИЕ И ДИНАМИКА РАЗВИТИЯ ПОБЕГОВЫХ СИСТЕМ БОКОПЛОДНЫХ МХОВ, "БОТАНИЧЕСКИЙ ЖУРНАЛ"

Использование ритмологического подхода позволило выявить особенности структурной и функциоиальной организации побеговых систем Rhytidiadelphus triquetrus, R. squarrosus, R. subpinnatus, Thuidium assimile и Cirrifillum piliferum и предложить классификацию побегов иа основе выполняемых ими функций. Длина годичных приростов у изученных бокоплодных мхов определяется видовой принадлежностью, погодными факторами и условиями местообитания. Наибольшие величины годичных приростов имеет Rhytidiadelphus squarrosus (до 10 см). Летом, во время затяжных дождей, когда изученные виды мхов несколько дней постоянно находились в обводненном состоянии, их прирост сначала увеличивался (до 5—6 мм в сутки у Rhytidiadelphus squarrosus), а затем снова уменьшался. У Rhytidiadelphus triquetrus, R. squarrosus, R. subpinnatus, Cirriphyllum piliferum от момента заложения перихециев до спороношения проходит полтора года.

Effect of copper and lead on lipid metabolism in bryophytes and lichens

Bryophytes and lichens have a widespread occurrence and can survive under extreme environmental conditions, such as drought, low temperatures, continuous light or prolonged darkness. It has been shown that lipid metabolism is sensitive to both metal response and metal resistance mechanisms in many organisms, including yeast, Silene cucubalus and in the marine brown algae Fucus spp. and Ascophyllum nodosum. In the present study, the effects of lead and copper on lipid metabolism have been studied in two moss species, Rhytidiadelphus squarrosus and Dicranum scoparium and also in the lichen Peltigera horizontalis with a cyanobacterial Nostoc photobiont.