The escalating global demand for polymer products and the consequent disposal challenge necessitate technological and sustainable solutions. Recent advances in the development of materials used in 3D printing equipment are described in this review, with a focus on new biocomposite materials. The investigation delves into biocomposites comprising PLA and its blends with other polymers, reinforced by plant fibers, with a particular focus on research conducted over the last five years. The information related to the raw materials’ physical, chemical, and processing properties necessary for creating biocomposite filament and printed parts were summarized. The best results in terms of tensile and flexural strength were presented and discussed, signposting future research avenues and desirable objectives. The findings elucidate that the inclusion of plant fibers led to a reduction in mechanical strength relative to pure PLA; however, when smaller particle sizes of plant fibers were added in volumes below 10%, it resulted in improved performance. Moreover, physical and/or chemical pretreatment of fibers, along with the isolation of cellulose fibrils, emerged as pivotal strategies for bolstering mechanical strengths. Noteworthy are the promising prospects presented by the incorporation of additives, while the refinement of printing parameters is key to improving the tensile and flexural strength of printed components.

Considering the water scarcity problems facing many countries, the need for water reuse can make activated carbon (AC) an essential product for modern society. In this context, to contribute with better activated carbons that could be used to serve in water treatment, this article discusses these materials production, using bamboo as raw material, and analyses their application effectiveness. The bamboo was collected, transformed into activated carbon, by simultaneous chemical and physical activations, and named H₃PO₄/H₂OAC. The obtained material was characterized by its yield, apparent density, ash content, thermogravimetric analysis, surface area, methylene blue and iodine indexes, pH and point of zero charge analysis, scanning electron microscopy and Boehm titration method. The AC was used as adsorbent for removing the metribuzin, 2,4-dichlorophenoxyacetic acid and furadan pesticides. The H₃PO₄/H₂OAC had a surface area of 1196.30 m².g^-1 and the obtained adsorption capacity was elevated for furadan (868.98 mg.g^-1), metribuzin (756.47 mg.g^-1) and 2,4-dichlorophenoxyacetic acid (274.70 mg.g^-1).

Vegetable fibers are increasingly used in biocomposites, but there is a need for further development in utilizing by-products like cocoa husks. Three-dimensional printing, through Fused Filament Fabrication (FFF), is advancing rapidly and may be of great interest for applying biocomposite materials. This study focuses on developing innovative and fully biodegradable filaments for the FFF process. PLA filaments were prepared using cellulose fibers derived from cocoa husks (5% mass ratio). One set of filaments incorporated fibers from untreated husks (UCFFs), while another set utilized fibers from chemically treated husks (TCFFs). The fabricated materials were analyzed using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) techniques, and they were also tested for tensile strength. ANOVA reveals that both UCFFs and TCFFs significantly predict tensile strength, with the UCFFs demonstrating an impressive R² value of 0.9981. The optimal tensile strength for the filament test specimens was 16.05 MPa for TCFF8 and 13.58 MPa for UCFF8, utilizing the same printing parameters: 70% infill and a layer thickness of 0.10 mm. Additionally, there was an 18% improvement in the tensile strength of the printed specimens using the filaments filled with chemically treated cocoa husk fibers compared to the filaments with untreated fibers.

CARVÃO ATIVADO A PARTIR DE BAMBU ( Bambusa vulgaris ) PARA REMOÇÃO DE AZUL DE METILENO: PREDIÇÕES PARA APLICAÇÕES AMBIENTAIS

Bamboo (Bambusa vulgaris) waste were used as a raw material for producing activated carbon (AC). The materials were collected and turned into AC by carbonization (500 °C, 1.67 °C.min-1, 60 min) and activation (800 °C, 10 °C.min-1, 60 min) processes with CO2 (100 mL.min-1). The obtained material (CO2 AC) was characterized by its yield, elemental analysis, ash content, methylene blue and iodine indexes, surface area (SBET), Boehm titration method, scanning electron microscopy and used as adsorbent for removing the methylene blue and phenol contaminants. The Langmuir and Freundlich isotherms models were selected for understanding the adsorption process. CO2 AC produced showed yield of 21.6%, carbon content of 82.13% and SBET of 856.78 m2.g-1, presenting rapid removal and high adsorption capacity for methylene blue (298.82 mg.g-1) and phenol (558.29 mg.g-1).

The development of alternatives for reuse of coconut shell allows inadequate solid residues disposal reduction and provides a novelty option close to the production sites. This paper aims to evaluate the tannin extraction potential of the green coconut mesocarp, as well as its adhesive capacity. Tannin extraction was performed with sodium sulfite diluted in water at 0%, 1%, 5% and 8% concentrations. It was observed which extraction resulted in better yield and characteristics to be used as an adhesive agent. The concentration of sodium sulfite at 5% allowed higher yields of tannin extraction. When compared to phenol formaldehyde, the tannin had similar adhesive characteristics such as 153.84 cp viscosity and 54.57% solid content. For the FT-IR spectroscopy analysis, dry samples of the coconut mesocarp were used. The peaks observed in the infrared spectrum of the green coconut mesocarp are characteristic of tannins found in biomass, presenting desirable chemical characteristics to be used as an adhesive agent. The coconut mesocarp is a material with potential for tannin extraction, making it suitable to be used in the gluing of panels.