This paper provides proof of concept that activated carbon (AC) may be readily produced using limited conversion methods and resources from sawdust of massaranduba (Manilkara huberi) wood, thereby obtaining value-added products. Sawdust was sieved and heat-treated in an oxygen-free muffle furnace at 500 °C to produce charcoal. The charcoal was activated in a tubular electric furnace at 850 °C while being purged with CO2 gas. Microstructural, thermal and physical properties of the three components: sawdust, charcoal and AC were compared by means of field emission scanning electron microscopy (FESEM), X-ray diffractometry (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), density and water adsorption/desorption measurements. The resulting AC had a large surface area as measured by Brunauer-Emmett-Teller (BET) comparable to other such values found in the literature. The large surface area was due to pore development at the microstructural level as shown by FESEM. XRD illustrated that sawdust had a semi-crystalline structure whereas charcoal and AC evidenced mostly amorphous structures. TGA and DSC showed that AC had high reactivity to moisture compared to sawdust and charcoal.

The objective of this study was to evaluate the effect of extractives soluble in hot water, besides final carbonization temperatures, on the gravimetric yield and properties of charcoal for waste of three native forest species from the Amazon region. Waste cuttings of Ipé, Grapia and Maçaranduba species, from the machine processing for joinery of a company in the State of Pará, were used. Carbonization was carried out in an adapted electric furnace with a heating rate of 1.67°C min^-1 and final temperatures of 500, 600 and 700°C. The waste was carbonized fresh after extraction in hot water to remove extractives. Gravimetric yields were analyzed, as well as chemical features and high heating value. In the evaluation of the experiment, arranged in a factorial scheme with three factors (species x temperature x material with and without extraction), and Principal Component Analysis used too. The presence of extractives (soluble in hot water) from wood waste had little influence on the gravimetric yield and immediate chemical composition of charcoal; however, it showed a greater high heating value and lower contents of hydrogen and nitrogen. The increase in the final carbonization temperature reduced the gravimetric yield in charcoal, the content of volatile materials and hydrogen, with a higher content of fixed carbon, carbon and high heating value. The treatments with the best energy characteristics were obtained from Ipé and Maçaranduba charcoals with extractives produced at 600°C, in addition to Ipê and Maçaranduba charcoals with and without extractives obtained at 700°C.

Thousands of tons of residual lignocellulosic biomass are produced and discarded by agroindustries in the Amazon. These biomasses could be harnessed and used in the preparation of activated carbon, in view of the growing demand for this product with high added value, however, little is known about their characteristics, in addition to their potential as precursors of activated carbon. Therefore, the aim of this work was to evaluate the potential of four different biomasses in the preparation and quality of activated carbon. Residues from the processing of the fruits of acai, babassu, Brazil nut, and oil palm were collected, characterized, carbonized, physically activated with CO₂, and characterized. The contents of the total extractives, insoluble lignin, minerals, holocellulose, and elemental (CHNS–O) were analyzed. The surface area and surface morphology were determined from the AC produced, and adsorption tests for methylene blue and phenol were performed. The four biomasses showed potential for use in the preparation of CA; the residues presented high contents of lignin (21.83–55.76%) and carbon (46.49–53.79%). AC were predominantly microporous, although small mesopores could be observed. The AC had a surface area of 569.65–1101.26 m² g⁻¹, a high methylene blue (93–390 mg g⁻¹), and phenol (159–595 mg g⁻¹) adsorption capacities. Babassu-AC stood out compared to the AC of the other analyzed biomasses, reaching the best results.

This study aimed to evaluate the effect of different pretreatments of Amazon piassava (Leopoldinia piassaba) fibers on microstructure, thermal, and physical properties of the ensuing activated carbons (ACs). ACs were prepared from untreated and pretreated piassava fibers by physical activation using CO₂ at 800°C. Pretreatments include: mercerization, corona discharge, and removal of extractives. Scanning electron micrographs showed the formation of nanoscale pores after the activation process of the charcoal. ACs from pretreated piassava fibers presented lower crystallinity and higher thermal stability than the untreated sample. ACs from Amazon piassava fibers are potential adsorbent materials for a myriad of applications.

This study aimed to determine the chemical and energetic composition of Brazil nut waste in the city of Castanhal-PA. Some of the material was crushed, sifted and stored for acclimatization and analysis. Molecular and immediate chemical analyses were performed on the raw material according to NBR standards. Another part was charred in Muffle furnace, with heating rate of 1.67 °C.min-1 and temperature of 450 °C for 60 minutes. For biomass, 55.76% of lignin and 2.61% of minerals were found. Means of 65.67% for volatiles were also found; 2.08% of ashes and 21.64% of fixed carbon. In the elementary, means of 53.54% of carbon and 0.11% of sulfur were found. For charcoal, 25.81% of volatiles were found; 1.76% of ashes and 67.50% of fixed carbon. Residues have high levels of lignin, fixed carbon and low ash contents, demonstrating potential for direct burning for energy, charcoal, activated carbon and biochar.

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).