RESUMO
Fungi were used as one of the most common bioremediation methods. From this perspective, our study highlights the optimization of Alizarin Red S (ARS) dye adsorption performance for the sodium alginate (SA) by using the fungus Aspergillus terreus (A. terreus) to form a composite bead and the possibility of its reusability. This was accomplished by mixing SA with different ratios of biomass powder of A. terreus, including 0%, 10%, 20%, 30%, and 40%, to form composite beads of A. terreus/SA-0%, A. terreus/SA-10%, A. terreus/SA-20%, A. terreus/SA-30%, and A. terreus/SA-40%, respectively. The ARS adsorption characteristics of these composite mixtures were analyzed at various mass ratios, temperatures, pH values, and initial concentrations. Moreover, sophisticated techniques, such as scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR), were employed to detect the morphological and chemical properties of this composite, respectively. The experimental results revealed that A. terreus/SA-20% composite beads have the highest adsorption capacity of 188 mg/g. Its optimum adsorption conditions were achieved at 45 ∘C and pH 3. Moreover, the ARS adsorption was well explained by the Langmuir isotherm (qm = 192.30 mg/g) and pseudo-second-order and intra-particle diffusion kinetics. The SEM and FTIR findings corroborated the superior uptake of A. terreus/SA-20% composite beads. Lastly, the A. terreus/SA-20% composite beads can be employed as an eco-friendly and sustainable alternative to other common adsorbents for ARS.
RESUMO
Mycoremediation is one of the most attractive, eco-friendly, and sustainable methods to mitigate the toxic effects of heavy metals. This study aimed to determine the mycoremediation capacity of metallophilic fungi isolated from heavy-metal-contaminated soil containing a high Fe(III) concentration (118.40 mg/kg). Four common fungal strains were isolated, including Curvularia lunata, Fusarium equiseti, Penicillium pinophilum, and Trichoderma harzianum. These fungal strains were exposed to gradually increasing concentrations of Fe(III) of 100, 200, 300, 400, 500, 600, 700, 800, 900, and 1000 mg/L. Sophisticated techniques and tests were employed to investigate the mycoremediation capability, including tolerance index (TI), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and adsorption isotherm. Furthermore, the impacts of initial concentration, pH, and temperature on the Fe(III) removal (%) and uptake capacity (mg/g) of the studied samples were investigated. The results were validated by statistical analysis using one-way ANOVA. It was found that the Fe(III) uptake with different ratios triggered alterations in the Fe(III) tolerance (TI) morphological (SEM), chemical (FTIR), and adsorption capacity properties. The highest Fe(III) tolerance for all studied fungal strains was achieved at 100 mg/L. Moreover, the optimum conditions of Fe(III) removal (%) for all studied fungal strains were within pH 7 and 28 °C, with similar performance at the initial Fe(III) concentration ranging from 50-200 mg/L. At the same time, the maximum Fe(III) uptake was achieved at pH 7, 20 °C, and 200 mg/L. Compared to other strains, the Fe(III) tolerance of T. harzianum was rise in the Fe(III) concentration. The Fe(III) uptake reaction was corroborated by best fitting with the Langmuir model, achieving optimum adsorption capacities of 61.34, 62.90, 63.30, and 72.46 mg/g for C.lunata, F. equiseti, P. pinophilum, T. harzianum, respectively. It can be deduced that the addressed fungi species can be applied in mycoremediation according to the utilized Fe(III) concentrations with more superiority for live T. harzianum.
