RESUMEN

Sustainable environmental management is an urgent problem that calls for innovative solutions to the problem of protecting and preserving the natural resources and ecosystems of the planet [...].

RESUMEN

Agriculture will face the issue of ensuring food security for a growing global population without compromising environmental security as demand for the world's food systems increases in the next decades. To provide enough food and reduce the harmful effects of chemical fertilization and improper disposal or reusing of agricultural wastes on the environment, will be required to apply current technologies in agroecosystems. Combining biotechnology and nanotechnology has the potential to transform agricultural practices and offer answers to both immediate and long-term issues. This review study seeks to identify, categorize, and characterize the so-called smart fertilizers as the future frontier of sustainable agriculture. The conventional fertilizer and smart fertilizers in general are covered in the first section of this review. Another key barrier preventing the widespread use of smart fertilizers in agriculture is the high cost of materials. Nevertheless, smart fertilizers are widely represented on the world market and are actively used in farms that have already switched to sustainable technologies. The advantages and disadvantages of various raw materials used to create smart fertilizers, with a focus on inorganic and organic materials, synthetic and natural polymers, along with their physical and chemical preparation processes, are contrasted in the following sections. The rate and the mechanism of release are covered. The purpose of this study is to provide a deep understanding of the advancements in smart fertilizers during the last ten years. Trends are also recognized and studied to provide insight for upcoming agricultural research projects.

RESUMEN

Due to its superior advantages in terms of electronegativity, metallic conductivity, mechanical flexibility, customizable surface chemistry, etc., 2D MXenes for nanogenerators have demonstrated significant progress. In order to push scientific design strategies for the practical application of nanogenerators from the viewpoints of the basic aspect and recent advancements, this systematic review covers the most recent developments of MXenes for nanogenerators in its first section. In the second section, the importance of renewable energy and an introduction to nanogenerators, major classifications, and their working principles are discussed. At the end of this section, various materials used for energy harvesting and frequent combos of MXene with other active materials are described in detail together with the essential framework of nanogenerators. In the third, fourth, and fifth sections, the materials used for nanogenerators, MXene synthesis along with its properties, and MXene nanocomposites with polymeric materials are discussed in detail with the recent progress and challenges for their use in nanogenerator applications. In the sixth section, a thorough discussion of the design strategies and internal improvement mechanisms of MXenes and the composite materials for nanogenerators with 3D printing technologies are presented. Finally, we summarize the key points discussed throughout this review and discuss some thoughts on potential approaches for nanocomposite materials based on MXenes that could be used in nanogenerators for better performance.

RESUMEN

This work characterizes two alternative materials to substitute the most expensive microbial fuel cells (MFCs) components: proton exchange membrane (PEM) and cathode. Crude glycerol biodegradation was studied in MFCs using a clay cup as a PEM and activated carbon and camphor carbon mixture (CAC) as a cathode. The cathode performance was compared with Platinum on carbon cloth. Two clay cup single-chamber MFCs were operated with each cathode and fed with 2000 mg/L of crude glycerol. Electrochemical properties were characterized by linear sweep voltammetry, electrochemical impedance spectroscopy, and chronoamperometry. Biodegradation efficiencies were estimated with the chemical oxygen demand (COD) removal percentage. MFCs with CAC showed a maximum power density of 100 mW/m2. This result was a 43.47% power response regarding MFCs with Platinum. COD removal efficiencies of 94% were achieved in 37 days for both cells. The Columbic efficiencies were 24.04% and 22.78% for the MFCs with Platinum and CAC. The economic analysis showed a cost of USD 9.97 for MFCs with CAC. This cost is five times lower than when using Platinum. MFCs utilizing clay cups and CAC showed an acceptable performance for the bioenergy production from crude glycerol biodegradation above all economic advantage in the cell cost.

Asunto(s)

Fuentes de Energía Bioeléctrica , Protones , Glicerol , Carbón Orgánico , Arcilla , Alcanfor , Platino (Metal) , Electricidad , Electrodos

RESUMEN

MXene has been identified as a new emerging material for various applications including energy storage, electronics, and bio-related due to its wider physicochemical characteristics. Further the formation of hybrid composites of MXene with other materials makes them interesting to utilize in multifunctional applications. The selection of magnetic nanomaterials for the formation of nanocomposite with MXene would be interesting for the utilization of magnetic characteristics along with MXene. However, the selection of the magnetic nanomaterials is important, as the magnetic characteristics of the ferrites vary with the stoichiometric composition of metal ions, particle shape and size. The selection of the electrolyte is also important for electrochemical energy storage applications, as the electrolyte could influence the electrochemical performance. Further, the external magnetic field also could influence the electrochemical performance. This review briefly discusses the synthesis method of MXene, and ferrite magnetic nanoparticles and their composite formation. We also discussed the recent progress made on the MXene/ferrite nanocomposite for potential applications in electrochemical supercapacitor applications. The possibility of magnetic field-assisted supercapacitor applications with electrolyte and electrode materials are discussed.

RESUMEN

A modified clay cup (cantarito) microbial fuel cell (C-MFCs) was designed to digest the biomass effluent from a nopal biogas (NBE). To improve the process, commercial acrylic varnish (AV) was applied to the C-MFCs. The experiment was performed as:Both-C-MFCs, painting of AV on both sides of the clay cup; In-C-MFCs, painting of AV on the internal side, and Out-C-MFCs painting of AV on the external side. The order for the maximum volumetric power densities were Both-C-MFCs (1841.99 mW/m3)>Out-C-MFCs (1023.74 mW/m3) >In-C-MFCs (448.90 mW/m3). The control experiment without applied varnish did not show a stable potential, supporting the idea that the acryloyl group in varnish could favor the performance. Finally, a 4-digits clock was powered with two, Both-C-MFCs connected in series; the microbial diversity in this format was explored and a well-defined bacterial community including members of the phyla Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria, Synergistetes and candidate division TM7 was found.