Three-dimensional (3D) graphene-based composite materials (3D GBCMs) have emerged as promising candidates for addressing critical challenges in water pollution remediation. This review selectively highlights the recent advancements in the application of 3D GBCMs to remove a wide range of contaminants, including heavy metals, dyes, salts, and pharmaceutical residues, from water. They owe their efficacy to their large surface area, interconnected porous structure, and functionalization potential. Three-dimensional GBCMs are promising materials for water filtration, offering capabilities such as heavy metal ion adsorption, the photocatalytic degradation of organic pollutants, and advanced desalination techniques like capacitive deionization (CDI) and solar desalination, thus providing sustainable solutions for obtaining freshwater from saline sources. Additionally, the factors influencing the pollutant removal capacities of 3D GBCMs, such as their material morphology, particle size, and porosity, are briefly discussed. Notably, the effect of the particle size on pollutant removal has not been extensively studied, and this review addresses that gap by exploring it in detail. Future research directions are also proposed, emphasizing the optimization and broader application of 3D GBCMs in environmental remediation. This review aims to provide valuable insights into the design and practical implementation of 3D GBCMs, offering guidance for their continued development in sustainable water treatment.

The advancement of modern 3D printing technologies has opened the possibilities to fabricate different spectrums of materials using these technologies. Binder jetting 3D printing is a shaping-debinding-sintering-based Additive manufacturing process that selectively fabricates the parts in a layer-by-layer fashion using the local imprinting of polymeric binder. This study aims to develop cobalt and nickel-free TiC-FeCr-based cermets that will contribute to the development of cermets towards green and cost-efficient materials. An effective approach to increase the densities of printed parts was to replace unimodal powder feedstocks with bimodal powders. Therefore, this work employed bimodal spherical powder (TiC and 430L ferritic stainless steel) to promote better densification of the cermet parts. Liquid phase vacuum sintering has been performed with different sintering temperatures to consolidate the cermet parts. Detailed analyses of the microstructure evolution, phase formation, and mechanical properties (hardness and fracture toughness) have been conducted. Further, thermodynamic simulations were conducted to calculate the phase diagram of the proposed cermet using the Thermo-Calc program. Microstructural analysis of consolidated cermets reveals a direct correlation between sintering temperature and carbide grain size, affecting their mechanical and physical properties. The best hardness and fracture toughness properties of TiC-FeCr-based cermets are 1102 ± 13 HV30 and 12.74 ± 1.38 MPa m1/2 respectively, were obtained after sintering at 1450 °C. Moreover, a systematic comparison is conducted with the same cermet composition fabricated with different additive manufacturing processes based on Laser powder bed fusion and Binder jetting 3D printing technology, demonstrating the potential and limitations of both technologies to fabricate brittle materials such as cermets.

Mitigation of CO2 emissions has been a major societal concern in recent decades, and post-combustion capture of CO2 is an effective strategy proposed by the research community. Hierarchical porous geopolymer monoliths were fabricated using extrusion-based 3D printing for CO2 capture. The kaolin-based viscoelastic paste was first formulated using alkali activators and plasticizer, and it was observed that the viscosity increased over time. Second, the 3D printed porous monoliths were treated using different post-processing conditions like thermal curing, hydrothermal curing, and high-temperature thermal treatment and their physico-mechanical properties and CO2 adsorptive were investigated. Thermally cured and heated specimens exhibited an amorphous phase, while zeolite phases were observed in the hydrothermally treated specimens. Printed and subsequently hydrothermally treated mechanically stable specimens showed significantly higher CO2 adsorption (1.22 mmol/g) than conventionally casted geopolymer (0.66 mmol/g). Combining 3D printing with geopolymer technology could offer a sustainable approach design and structure adsorbents for CO2 capture.

Entropy-stabilized Ultra High-Temperature Ceramics (UHTC) offer a groundbreaking solution to the challenges of extreme environments, showcasing enhanced mechanical properties, thermal stability, and resistance to oxidation at high temperatures. The consolidation of UHTC by ultra-fast high-temperature sintering (UHS) significantly reduces processing times and temperature and can produce dense high-performance ceramics with superior mechanical properties. This study reports the pressureless synthesis and consolidation of the entropy-stabilized (Hf0.25Zr0.25Ti0.25V0.25)B2-B4C composite through UHS within 1 minute, starting from transition metal diboride powders. B4C acts as an effective sintering aid, promoting the densification of the system and the formation of a nearly single-phase hexagonal diboride with a diboride-eutectic phase. Furthermore, a secondary minor hexagonal phase rich in V and Zr is formed close to the eutectic regions. Sintering currents of 40 A were necessary to reach densities higher than 90 % under pressureless conditions, achieving nano hardness higher than 27.3 GPa, comparable with high-entropy diborides produced by Spark Plasma Sintering. The study highlights the entropy-stabilized phase formation, diffusion, densification, and grain growth mechanisms involved during UHS. The work contributes to the understanding of entropy-stabilized ceramics produced by UHS as a faster and less energy-consuming process than conventional sintering methods.

In this study, porous Cu-Al-Si intermetallic compounds with three-dimensional structures were rapidly prepared by a novel self-exothermic reaction. By this method, Si was successfully solid-solved into CuAl intermetallic compounds and achieved better fusion with them. The effects of Si addition on their oxidation resistance and corrosion resistance were compared. The findings indicate that the minimum weight gain of the Cu-Al-Si product is only 1.48 % after oxidation at 800 °C for 288 h. Si facilitates the creation of a continuous Al2O3 protective layer on the surface of the porous Cu-Al-Si intermetallics skeleton, thereby preserving its internal structure while significantly enhancing its oxidation resistance. The incorporation of Si to Cu-Al intermetallics enhances the stability of the passivation film on the material's surface, increases the resistance of the passivation film, and effectively restricts the electrochemical reaction between the material and the corrosive medium.

Bioelectronics, a field pivotal in monitoring and stimulating biological processes, demands innovative nanomaterials as detection platforms. Two-dimensional (2D) materials, with their thin structures and exceptional physicochemical properties, have emerged as critical substances in this research. However, these materials face challenges in biomedical applications due to issues related to their biological compatibility, adaptability, functionality, and nano-bio surface characteristics. This review examines surface modifications using covalent and non-covalent-based polymer-functionalization strategies to overcome these limitations by enhancing the biological compatibility, adaptability, and functionality of 2D nanomaterials. These surface modifications aim to create stable and long-lasting therapeutic effects, significantly paving the way for the practical application of polymer-functionalized 2D materials in biosensors and bioelectronics. The review paper critically summarizes the surface functionalization of 2D nanomaterials with biocompatible polymers, including g-C3N4, graphene family, MXene, BP, MOF, and TMDCs, highlighting their current state, physicochemical structures, synthesis methods, material characteristics, and applications in biosensors and bioelectronics. The paper concludes with a discussion of prospects, challenges, and numerous opportunities in the evolving field of bioelectronics.

Population growth in recent years has led to increased wastewater production and pollution of water resources. This situation also heavily affects Bolivia, so wastewater treatment methods and materials suitable for Bolivian society should be explored. This study investigated the natural Bolivian Zeolite (BZ) and its NaCl-modified structure (NaBZ) as adsorbents for cadmium removal from water. The natural BZ and the modified form NaBZ were investigated by different physicochemical characterization techniques. Furthermore, XPS and FT-IR techniques were used to investigate the adsorption mechanisms. The cadmium adsorption on BZ and NaBZ was analyzed using various mathematical models, and the Langmuir model provided a better description of the experimental adsorption data with cadmium adsorption capacities of 20.2 and 25.6 mg/g for BZ and NaBZ, respectively. The adsorption followed the pseudo-second order kinetics. The effect of different parameters, such as initial cadmium concentration and pH on the adsorption was studied. In addition, the results of the regeneration test indicated that both BZ and NaBZ can be regenerated by using hydrochloric acid (HCl). Finally, the adsorption experiment of BZ and NaBZ on a real water sample (brine from Salar de Uyuni salt flat) containing a mixture of different heavy metals was carried out. The results obtained in this study demonstrate the effectiveness of natural BZ and modified NaBZ in the removal of heavy metals from wastewater.

CO2 capture and conversion using structured porous sorbents and catalysts is a solution to help the decarbonization of emission-intensive industries. Furthermore, porous sorbents have recently been considered for direct air capture to achieve negative CO2 emissions. Several new prototypes and swing adsorption technologies for CO2 capture use structured laminates and honeycomb sorbents to lower the energy penalty and improve process efficiency and kinetics. The challenges lie in tailoring and optimizing structured sorbents for their CO2 working capacity, selectivity over other components, the effect of impurities and humidity, mass and heat transfer kinetics, and mechanical and chemical durability, which are specific to the exhaust system and flue gas composition. Recent developments in the structuring of sorbents are reviewed with a focus on the scalable approaches to improve the performance of postcombustion CO2 capture and direct air capture processes.

Engineering the interfacial interaction between the active metal element and support material is a promising strategy for improving the performance of catalysts toward CO2 methanation. Herein, the Ni-doped rare-earth metal-based A-site substituted perovskite-type oxide catalysts (Ni/AMnO3; A = Sm, La, Nd, Ce, Pr) were synthesized by auto-combustion method, thoroughly characterized, and evaluated for CO2 methanation reaction. The XRD analysis confirmed the perovskite structure and the formation of nano-size particles with crystallite sizes ranging from 18 to 47 nm. The Ni/CeMnO3 catalyst exhibited a higher CO2 conversion rate of 6.6 × 10−5 molCO2 gcat−1 s−1 and high selectivity towards CH4 formation due to the surface composition of the active sites and capability to activate CO2 molecules under redox property adopted associative and dissociative mechanisms. The higher activity of the catalyst could be attributed to the strong metal-support interface, available active sites, surface basicity, and higher surface area. XRD analysis of spent catalysts showed enlarged crystallite size, indicating particle aggregation during the reaction; nevertheless, the cerium-containing catalyst displayed the least increase, demonstrating resilience, structural stability, and potential for CO2 methanation reaction.

Hierarchical cellular ceramics have attracted considerable interest due to their versatility and unique physico-mechanical effectiveness for advanced applications. Tailorable alumina foams with low shrinkage were fabricated through an innovative combination of 3D printing and sacrificial templating with low environmental footprint. The viscoelastic pastes were formulated using the aqueous-based solution of binder, dispersant, and plasticizer with different volumes of α-alumina and lightweight hollow microspheres (HMs) as a template. The solid-to-liquid ratio increased 53–80 vol% with the inclusion of HMs for printable rheology. Cellular architectures of alumina were structured through a material extrusion-based technique and then thermally treated at 1200 °C. Finally, the alumina monoliths achieved a ∼55–93 % porosity with three different types of adjustable pores, produced by combining 3D printing, burning of templates, and inter-particle voids. The HMs generated spherical pores (7–47 µm) in the printing struts with reduced CO2 emissions compared to conventional sacrificial porogens during the burnout process.