Inga Zinicovscaia, Alexey Safonov, Varvara Tregubova, Victor Ilin, Liliana Cepoi, Tatiana Chiriac, Ludmila Rudi and Marina V. Frontasyeva
Spirulina platensis biomass is widely applied for different technological purposes. The process of lanthanum, chromium, uranium and vanadium accumulation and biosorption by Spirulina platensis biomass from single- and multi-component systems was studied. The influence of multi-component system on the spirulina biomass growth was less pronounced in comparison with the single-component ones. To trace the uptake of metals by spirulina biomass the neutron activation analysis was used. In the experiment on the accumulation the efficiency of studied metal uptake changes in the following order: La(V) > Cr(III) > U(VI) > V(V) (single-metal solutions) and Cr(III) > La(V) > V(V) > U(VI) (multi-metal system). The process of metals biosorption was studied during a two-hour experiment. The highest rate of metal adsorption for single-component systems was observed for lanthanum and chromium. While for the multi-component system the significant increase of vanadium and chromium content in biomass was observed. In biosorption experiments the rate of biosorption and the Kd value were calculated for each metal. Fourier transform infrared spectroscopy was used to identify functional groups responsible for metal binding. The results of the present work show that spirulina biomass can be implemented as a low-cost sorbent for metal removal from industrial wastewater.
Amjad Mohammad Karimi, Soroor Sadeghi and Farhad Salimi
A new biodesulphurization method has been considered using Pseudomonas aeruginosa supported on polyethylene (PE) for biodesulphurization (BDS) of thiophene as an aromatic sulphur model compound of crude oils. Also the biodegradation of thiophene has been modified in the presence of potassium hexacyanoferrate(III) as a terminal electron acceptor to approach the maximum biodesulphurization efficiency. The obtaining results according to UV-Spectrophotometry at 240 nm, 83.3% of thiophene at the primary concentration of 50 mg/dm3, pH = 7, by 0.5 g of biocatalyst in 37°C after 4 h of contact time has been removed. The bacterial cells exhibited a greater and faster biodegradation in the presence of potassium hexacyanoferrate(III) and 94.8% of thiophene has been removed after 3 h of contact time. Kinetic study predicted chemisorption of thiophene on the surface of the biocatalyst, as it followed the pseudo-second-order rate equation. Morphology and surface functional groups of the biocatalyst have been investigated by SEM and FT-IR, respectively.
In the work, adsorption of Cu2+ ions onto almond shell were investigated under different operational conditions. Almond shell was used without any pretreatment prior to the tests. The optimum conditions for adsorption of Cu2+ ions through almond shell were determined to be; pH 5.0, temperature 20°C, shaking rate 125 rpm, sorbent dose 0.3 g and initial Cu2+ ion concentration 50 mg/dm3. The equilibrium duration of the system was 60 minutes. The sorption capacities of the sorbents were predicted with the aid of equilibrium and kinetic models. The interactions of peanut shell with metal ions were constituted by SEM, EDX, FT-IR, XRD and AFM. The pseudo-first-order, pseudo-second-order, Weber-Morris, Elovich model and Bangham kinetic models were applied to test the experimental data. The Cu+2 ions adsorption onto almond shell was better defined by the pseudo-second-order kinetic model, for initial pH. The equilibrium data were evaluated using Langmuir, Freundlich, Temkin, D-R and Harkins Jura isotherms. The highest R2 value in isotherm studies was obtained from Langmiur isotherm (R2 = 0.98) for the inlet concentration.