Biosorption of lead ions by cyanobacteria Spirulina platensis: kinetics, equilibrium and thermodynamic study

The potential use of dry Spirulina platensis biomass to remove lead ions from aqueous solution was investigated. Effects of various parameters such as contact time, temperature, dosage of biosorbent, initial pH, and initial concentration of lead were investigated in the batch adsorption mode. The highest lead removal of 5.7 mg/g was obtained at pH 5, biomass dosage of 0.5 g, initial lead concentration of 60 mg/L. The Langmuir and Freundlich models fit the experimental data (R2 > 0.99), while the kinetic data was best described using the pseudo second-order kinetic model (R2 > 0.99). FTIR spectra indicated that the metal removal takes place through binding to OH, C=O and P=O groups. Lead was efficiently recovered from biomass by mineral acids, while using CH3COOH and NaOH as eluents the biomass maintained high biosorption capacity during three cycles. This study demonstrates the potential of using Spirulina platensis as biosorbent to remove lead from industrial wastewater

Application of <i>Shewanella xiamenensis</i> Placed on Zeolite in Treatment of Silver-Containing Effluents

The adsorption properties of Shewanella xiamenensis immobilized on zeolite have been evaluated in order to determine its applicability for remediation of silver-containing effluents with different chemical composition. The effects of pH (2.0–6.0), contact time (15–150 min), silver concentration (10–100 mg/L) and temperature (20–50 °C) on the bio-zeolite adsorption efficiency were investigated in batch experiments. The optimal pH for metal ions removal was in the range of 4.0–6.0, while the time required to attained equilibrium lay between 60 and 150 min. The adsorption of silver was described by a pseudo-second-order kinetic model in Ag- and Ag-Cu-Ni-Zn systems, while in Ag-Cu systems, it fitted well the pseudo-first-order kinetic model. The maximum adsorption capacities of silver on bio-zeolite calculated from the Langmuir model were 14.8 mg/g (Ag system), 32.5 mg/g (Ag-Cu system) and 12.8 mg/g (Ag-Cu-Ni-Zn system). The thermodynamic parameters showed that the adsorption of metal ions onto bio-zeolite was a spontaneous entropy-driven process

Mosses as Bioindicators of Heavy Metal Air Pollution in the Lockdown Period Adopted to Cope with the COVID-19 Pandemic

The coronavirus disease, COVID-19, has had a great negative impact on human health and economies all over the world. To prevent the spread of infection in many countries, including the Russian Federation, public life was restricted. To assess the impact of the taken actions on air quality in the Moscow region, in June 2020, mosses Pleurosium shreberi were collected at 19 sites considered as polluted in the territory of the region based on the results of the previous moss surveys. The content of Cd, Cr, Cu, Fe, Ni, and Pb in the moss samples was determined using atomic absorption spectrometry. The obtained values were compared with the data from the moss survey performed in June 2019 at the same sampling sites. Compared to 2019 data, the Cd content in moss samples decreased by 2&ndash;46%, while the iron content increased by 3&ndash;127%. The content of Cu, Ni, and Pb in mosses decreased at most sampling sites, except for the eastern part of the Moscow region, where a considerable number of engineering and metal processing plants operate. The stay-at-home order issued in the Moscow region resulted in a reduction of vehicle emissions affecting air quality, while the negative impact of the industrial sector remained at the level of 2019 or even increased

Efficient Removal of Metals from Synthetic and Real Galvanic Zinc–Containing Effluents by Brewer’s Yeast Saccharomyces cerevisiae

The performance of the brewer&rsquo;s yeast Saccharomyces cerevisiae to remove metal ions from four batch systems, namely Zn(II), Zn(II)-Sr(II)-Cu(II), Zn(II)-Ni(II)-Cu(II), and Zn(II)-Sr(II)-Cu(II)-Ba(II), and one real effluent was evaluated. Yeast biosorption capacity under different pH, temperature, initial zinc concentration, and contact time was investigated. The optimal pH for removal of metal ions present in the analyzed solution (Zn, Cu, Ni, Sr, and Ba) varied from 3.0 to 6.0. The biosorption process for zinc ions in all systems obeys Langmuir adsorption isotherm, and, in some cases, the Freundlich model was applicable as well. The kinetics of metal ions biosorption was described by pseudo-first-order, pseudo-second-order, and Elovich models. Thermodynamic calculations showed that metal biosorption was a spontaneous process. The two-stage sequential scheme of zinc ions removal from real effluent by the addition of different dosages of new sorbent allowed us to achieve a high efficiency of Zn(II) ions removal from the effluent. FTIR revealed that OH, C=C, C=O, C&ndash;H, C&ndash;N, and NH groups were the main biosorption sites for metal ions

Arthrospira platensis as Bioremediator of Rhenium Mono- and Polymetallic Synthetic Effluents

Rhenium is a scarce and highly important metal for industry and technology. In the present study, the cyanobacterium Arthrospira platensis (Spirulina) was used to remove rhenium and related elements (Mo and Cu) from mono- and polymetallic synthetic effluents. Metal ions in different concentrations were added to the culture medium on the first, third, and fifth days of biomass growth, and their uptake by the biomass was traced using ICP-AES technique. The accumulation of rhenium in the biomass was dependent on the chemical composition of the effluents, and the highest uptake of 161 mg/kg was achieved in the Re-Cu system. The presence of rhenium, copper, and molybdenum affected the productivity of Spirulina biomass and its biochemical composition (proteins, carbohydrates, lipids, phycobiliproteins, the content of chlorophyll &alpha; and &beta;-carotene). With the growth of biomass in the presence of rhenium or rhenium and molybdenum, a pronounced increase in productivity and protein content was observed. The presence of copper in systems has a negative effect on biomass productivity and biochemical composition. Arthrospira platensis may be of interest as a bioremediator of rhenium-containing effluents of various chemical compositions

Treatment of Rhenium-Containing Effluents Using Environmentally Friendly Sorbent, Saccharomyces cerevisiae Biomass

Yeast Saccharomyces cerevisiae biomass was applied for rhenium and accompanying elements (copper and molybdenum) removal from single- and multi-component systems (Re, Re-Mo, Re-Cu, and Re-Mo-Cu). Yeast biomass was characterized using X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. The effects of biosorption experimental parameters such as solution pH (2.0–6.0), rhenium concentration (10–100 mg/L), time of interaction (5–120 min), and temperature (20–50 °C) have been discussed in detail. Maximum removal of rhenium (75–84%) and molybdenum (85%) was attained at pH 2.0, while pH 3.0–5.0 was more favorable for copper ions removal (53–68%). The Langmuir, Freundlich, and Temkin isotherm models were used to describe the equilibrium sorption of rhenium on yeast biomass. Langmuir isotherm shows the maximum yeast adsorption capacities toward rhenium ions ranged between 7.7 and 33 mg/g. Several kinetic models (pseudo-first-order, pseudo-second-order, and Elovich) were applied to define the best correlation for each metal. Biosorption of metal ions was well-fitted by Elovich and pseudo-first-order models. The negative free energy reflected the feasibility and spontaneous nature of the biosorption process. Saccharomyces cerevisiae biomass can be considered as a perspective biosorbent for metal removal

Study on the SBA-15 Silica and ETS-10 Titanosilicate as Efficient Adsorbents for Cu(II) Removal from Aqueous Solution

The efficiency of Cu(II) removal from aqueous solution by two adsorbents, silica SBA-15 and titanosilicate ETS-10, was investigated. Effects of various experimental parameters such as: contact time, pH, initial copper concentration, adsorbent dosage, temperature were investigated in order to determine the maximum adsorption capacity of the adsorbents. The maximum adsorption capacity of silica SBA-15 was achieved at pH 5.0, and of titanosilicate ETS-10 at pH 6.0. The Freundlich, Langmuir, and Temkin isotherm models were applied in order to describe the equilibrium adsorption of Cu(II) by the studied adsorbents. Equilibrium data fitted well to the Langmuir model with a higher adsorption capacity of ETS-10 (172.53 mg&middot;g&minus;1) towards Cu(II) than SBA-15 (52.71 mg&middot;g&minus;1). Pseudo-first- and pseudo-second-order, Elovich, and Weber&ndash;Morris intraparticle diffusion models were used for description of the experimental kinetic data. It was found that the pseudo-first-order and pseudo-second-order kinetic models were the best applicable models to describe the adsorption kinetic data. Thermodynamic parameters that characterize the process indicated that the adsorption of Cu(II) onto the two adsorbents is spontaneous and endothermic

Biosorption and Bioaccumulation Capacity of <i>Arthrospira platensis</i> toward Yttrium Ions

Yttrium is an element of critical importance for industry and technology. Cyanobacteria Arthrospira platensis was employed for Y(III) recovery from contaminated wastewater through biosorption and bioaccumulation processes. The effect of pH of a solution, contact time, temperature, and initial Y(III) concentration on the adsorption behaviour of Arthrospira platensis were studied. The maximum adsorption capacity of 719.8 mg/g was attained at a pH of 3, temperature of 20 °C, and adsorption time of 3 min. The Langmuir and Freundlich isotherm models were suitable to describe the equilibrium of the biosorption, while kinetic of the process followed the pseudo-first-order model. Thermodynamic parameters showed that the biosorption process was spontaneous and exothermic in nature. In bioaccumulation experiments, Arthrospira platensis was able to remove up to 70% of Y(III) from the solution. Beside biomass uptake capacity, the toxic effect of Y(III) on the biomass productivity and biochemical composition was assessed. Thus, Y(III) in concentration of 10–30 mg/L led to a decrease in the content of proteins, carbohydrates, and phycobiliproteins in the biomass and had no significant negative impact on productivity and photosynthetic pigments content. Experiments performed using Arthrospira platensis showed that biological objects have a great potential to be applied for the recovery of rare earth elements from wastewater

Biosorption and Bioaccumulation Capacity of Arthrospira platensis toward Yttrium Ions

Yttrium is an element of critical importance for industry and technology. Cyanobacteria Arthrospira platensis was employed for Y(III) recovery from contaminated wastewater through biosorption and bioaccumulation processes. The effect of pH of a solution, contact time, temperature, and initial Y(III) concentration on the adsorption behaviour of Arthrospira platensis were studied. The maximum adsorption capacity of 719.8 mg/g was attained at a pH of 3, temperature of 20 &deg;C, and adsorption time of 3 min. The Langmuir and Freundlich isotherm models were suitable to describe the equilibrium of the biosorption, while kinetic of the process followed the pseudo-first-order model. Thermodynamic parameters showed that the biosorption process was spontaneous and exothermic in nature. In bioaccumulation experiments, Arthrospira platensis was able to remove up to 70% of Y(III) from the solution. Beside biomass uptake capacity, the toxic effect of Y(III) on the biomass productivity and biochemical composition was assessed. Thus, Y(III) in concentration of 10&ndash;30 mg/L led to a decrease in the content of proteins, carbohydrates, and phycobiliproteins in the biomass and had no significant negative impact on productivity and photosynthetic pigments content. Experiments performed using Arthrospira platensis showed that biological objects have a great potential to be applied for the recovery of rare earth elements from wastewater