A Treatment of Wastewater Containing Safranin O Using Immobilized Myriophyllum spicatum L. onto Polyacrylonitrile/Polyvinylpyrrodlidone Biosorbent

Biosorption of Remazol Brilliant Blue R textile dye using Clostridium beijerinckii by biorefinery approach

The current study proposes RBBR biosorption by Clostridium beijerinckii DSMZ 6422 biomass remaining after biobutanol production from pumpkin peel (PP) by a zero-waste approach. Efficient biobutanol production was achieved by investigating initial PP concentrations (5-20% without or with enzymatic hydrolysis) and fermentation time. According to this, the highest concentrations of biobutanol and total ABE were obtained as 4.87 g/L and 8.13 g/L in the presence of 10% PP without enzymatic hydrolysis at 96 h. Furthermore, based on the zero-waste approach, C. beijerinckii DSMZ 6422 biomass obtained after biofuel production was used as a biosorbent for the removal of RBBR dye. Response surface methodology (RSM), commonly utilized for the experimental design, was used to specify the optimized biosorption conditions of RBBR, including initial dye concentration (50-200 mg/L), initial pH (2-6), biosorbent concentration (1-3 g/L), and contact time (0-240 min). The highest biosorption under optimized conditions with RSM was 98% in the presence of 194.36 mg/L RBBR and 2.65 g/L biosorbent at pH 2 and 15 min. This is the first report in the literature about the biosorption of RBBR dye by anaerobic C. beijerinckii biomass after the biobutanol production process. This study also shows the efficient usage of agricultural and microbial wastes in different areas based on zero-waste applications.

A Comparative Study of Cr(VI) Sorption by Aureobasidium pullulans AKW Biomass and Its Extracellular Melanin: Complementary Modeling with Equilibrium Isotherms, Kinetic Studies, and Decision Tree Modeling

Melanin as a natural polymer is found in all living organisms, and plays an important role in protecting the body from harmful UV rays from the sun. The efficiency of fungal biomass (Aureobasidium pullulans) and its extracellular melanin as Cr(VI) biosorbents was comparatively considered. The efficiency of Cr(VI) biosorption by the two sorbents used was augmented up to 240 min. The maximum sorption capacities were 485.747 (fungus biomass) and 595.974 (melanin) mg/g. The practical data were merely fitted to both Langmuir and Freundlich isotherms. The kinetics of the biosorption process obeyed the pseudo-first-order. Melanin was superior in Cr(VI) sorption than fungal biomass. Furthermore, four independent variables (contact time, initial concentration of Cr(VI), biosorbent dosage, and pH,) were modeled by the two decision trees (DTs). Conversely, to equilibrium isotherms and kinetic studies, DT of fungal biomass had lower errors compared to DT of melanin. Lately, the DTs improved the efficacy of the Cr(VI) removal process, thus introducing complementary and alternative solutions to equilibrium isotherms and kinetic studies. The Cr(VI) biosorption onto the biosorbents was confirmed and elucidated through FTIR, SEM, and EDX investigations. Conclusively, this is the first report study attaining the biosorption of Cr(VI) by biomass of A. pullulans and its extracellular melanin among equilibrium isotherms, kinetic study, and algorithmic decision tree modeling.

Pseudomonas alcaliphila NEWG-2 as biosorbent agent for methylene blue dye: optimization, equilibrium isotherms, and kinetic processes

In comparison to physicochemical and chemical methods, microbial dye biosorption is regarded as an eco-effective and economically viable alternative and is a widely applied method due to its high efficiency and compatibility with the environment. Therefore, the idea of this study is to clarify to what extent the viable cells and the dry biomass of Pseudomonas alcaliphila NEWG-2 can improve the biosorption of methylene blue (MB) from a synthetic wastewater sample. The array of Taguchi paradigm has been conducted to ascertain five variables affecting the biosorption of MB by broth forms of P. alcaliphila NEWG. The data of MB biosorption were familiar to the predicted ones, indicating the precision of the Taguchi model's prediction. The maximum biosorption of MB (87.14%) was achieved at pH 8, after 60 h, in a medium containing 15 mg/ml MB, 2.5% glucose, and 2% peptone, with sorting the highest signal-to-noise ratio (38.80). FTIR spectra detected various functional groups (primary alcohol, α, β-unsaturated ester, symmetric NH2 bending, and strong C-O stretching) on the bacterial cell wall that participated in the biosorption of MB. Furthermore, the spectacular MB biosorption ability was validated by equilibrium isotherms and kinetic studies (the dry biomass form), which were derived from the Langmuir model (qmax = 68.827 mg/g). The equilibrium time was achieved in about 60 min, with 70.5% of MB removal. The biosorption kinetic profile might be adequately represented by pseudo-second order and Elovich models. The changes in the bacterial cells before and after the biosorption of MB were characterized using a scanning electron microscope. As realized from the aforementioned data, the bacterium is a talented, effective, eco-friendly, and low-cost bio-sorbent for the decolorization and remedy of an industrial effluent containing MB from an aqueous environment. The current outcomes in the biosorption of MB molecules promote the use of the bacterial strain as viable cells and/or dry biomass in ecosystem restoration, environmental cleanup, and bioremediation studies.

Prediction of heavy metal biosorption mechanism through studying isotherm kinetic equations

The kinetic constants for free and immobilized cells were determined by measuring reaction rates at different metal concentrations at the optimum reaction conditions. (K_max and V_max) were calculated from the slope and intercept of the straight lines. The pseudo-second-order rate constants are derived based on the sorption capacity of the solid phase, where K2 is the rate constant for the pseudo-second-order model. Determined experimentally by plotting t/q against t. The mean free vitality of adsorption (E) was figured as 2.62 kJ mol^-1 and the extent of E communicated gives data on the adsorption mechanism. An E value ranging from 1 to 8 indicates physisorption and 8-16 kJ mol^-1 predicts ion exchange. Thus, the evaluated value of 2.62 kJ mol^-1 predicts the phenomenon of physisorption, which suggests that metal ions were favorably adsorbed by this biosorbent in a multi-layer fashion. The overall result suggested that 98.2% of U (VI) by biosorption of U in the mechanism of adsorption will include chemisorption mechanistic pathway: Langmuir, Freundlich, equations and the values of K_f 5.791 where K_L 3.9 were determined from the linear plot of log q_e vs. log C_e at 30 °C, indicating that metal ions were favorably adsorbed by this biosorbent in a multi-layer fashion and instrumentation of beads characterizing novel Binding sites using FTIR & SEM beside change in peaks position which assigned for its groups confirm biosorption of metal.