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The research in sustainable development goals (SDG) increases year by year since its approval in 2015. Typically, after a phase of exponential growth, the number of publications increases at lower rates, suggesting a consolidation process in which literature reviews become a relevant and high-evidence type of document. In this context, the aim of this study was to perform an unprecedented bibliometric analysis of literature reviews on SDG to assess the evolution and consolidation of the scientific research. Article reviews on SDG from 2015 to 2022 were retrieved from Web of Science core collection and a descriptive bibliometric analysis was performed by growth rate, research area, source, citation, and region. Mapping and cluster analysis using keyword co-occurrence, co-authorship, and bibliographic coupling were also applied. The result revealed that SDG is a fast-growing field, with a trend in the diversification of research areas. Most of the review documents were categorized in general aspects of sustainability. Technology (SDG 9) and economic growth (SDG 8) were spotted as hidden key research areas. This result is contrary to previous bibliometric studies on SDG, demonstrating the rapid evolution and change in the field. In addition, literature reviews on reduced inequalities (SDG 10), gender equality (SDG 5); oceans, seas, and marine environments (SDG 14); and peace, justice, and strong institutions (SDG 16) were revealed as research gaps. Thus, the results demonstrated that the research on SDG cannot yet be considered a consolidated area of research, as it leaves many SDG unexplored. Future research has been proposed accordingly.

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The main objective of this study was to synthesize a nanocomposite using graphene and manganese ferrite nanoparticles (MnFe2O4-G) and to evaluate its antibacterial activity for water treatment purposes. Its morphological characteristics were evaluated by instrumental techniques, such as scanning electron microscopy and transmission electron microscopy. The characterization results indicated that the nanocomposite presented nanoparticles of approximately 25 nm well dispersed in transparent and large (14 μm) graphene nanosheets. The antibacterial activity was evaluated in a batch experiment using a concentration of 40 μg mL-1 of nanocomposite (MnFe2O4-G, bare MnFe2O4 nanoparticles or graphene oxide), 1x105 CFU mL-1 of Escherichia coli, and 8 h of contact time at room temperature. The highest antibacterial capacity was observed for the hybrid nanocomposite (91.91%), due to the synergic effect of graphene and MnFe2O4 nanoparticles. Various mechanisms were proposed to explain the effective antibacterial activity of MnFe2O4-G, such as wrapping, oxidative stress, sharp-edge cutting effect, among others. The results showed that MnFe2O4-G is a potential alternative in water treatment processes as an antibacterial agent.

The present research aimed to evaluate the photocatalytic activity of reduced graphene oxide and manganese ferrite nanocomposite supported on eucalyptus wood ash waste (WA) from industrial boilers, for the decolorization of methylene blue (MB) solutions, using sunlight as an irradiation source. For this, the photocatalyst named MnFe2O4-G@WA was synthesized by a solvothermal method and characterized by analyzes of scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, Brunauer–Emmett–Teller and zeta potential. Firstly, the photocatalyst was evaluated for photocatalytic decolorization of MB under different reaction conditions. Then, the influence of pH, photocatalyst dose and H2O2 was evaluated. MnFe2O4-G@WA showed 94% of efficiency for photocatalytic decolorization of MB under operating conditions of solar irradiation, 0.25 g/L of catalyst, 300 mg/L of H2O2. The proposed degradation reaction mechanism suggested that the photodegradation of MB was through a synergistic mechanism of photocatalysis and photo-Fenton reactions, with the combined action of the three materials used. The data adjusted to the first order kinetics from the Langmuir–Hinshelwood model. In addition, MnFe2O4-G@WA showed high stability, maintaining its efficiency above 90% after 5 cycles. The results indicated that the nanophotocatalyst is a potential technology for the decolorization of MB solutions.