Search

Sugarcane bagasse is one of the greatest biomass residues obtained from fuel industry, and the lignin present in sugarcane fibers is rich in phenolic compounds, which can be used to replace petroleum-derived phenols in the formulation of adhesives, phenolic resins, plasticizers, paints, among others. This work presents an alternative for synthesizing and applying bio-oil based benzoxazine resins in the fabrication of “green” medium density fiberboard. In this new concept, the wood fiber is substituted by the sugarcane bagasse fiber, and the fossil-based resin is substituted by the bio-based benzoxazine resin. To produce the bio-oil resin, 200.0 g of bio-oil, 64.9 mL of formaldehyde, 39.4 mL of aniline, and 80.0 mL of butanone were added along the different process stages. Three concentrations of bio-oil resin were used to produce fiberboards, 25, 30, and 35%. The results of characterizations were compared with fiberboards made with regular urea–formaldehyde resin, in the same concentrations. Results indicated that bio-oil can be used successfully for the development of a thermosetting resin (BO-resin), as observed by thermal and spectroscopic analysis. All BO-resin MDF formulations had densities according to international standards, between 651 and 800 kg m-3, and reached the required thickness swelling when applied in concentration of 35% resin. The modulus of rupture (MOR) showed elevated values (around 15 MPa), similar to fiberboards made from urea–formaldehyde resins. These results indicate the promising potential of using sugarcane bagasse for the full development of novel bio-based materials with technological application.

Palm oil production generates oil palm mesocarp fiber (OPMF) as the main lignocellulosic waste from the oil/fruit separation process. The plentiful OPMF can be used for diverse applications, such as reinforcement in polymeric matrix composites or to produce glucose for second-generation ethanol. In both applications, surface properties are essential, and the presence of silica bodies is usually harmful. In the present study, three treatments to remove silica bodies were evaluated as follows: hydrothermal (HT), alkali (AT), and sodium citrate solution (ST). Morphological and structural characteristics of untreated and treated fibers were determined using scanning electron microscopy and energy-dispersive X-ray spectroscopy. Many silica bodies attached to the untreated OPMF surface were observed. The treatments partially removed the silica bodies from the surface. AT was superior, with a removal rate of approximately 91% as quantified by microwave-induced plasma optical emission spectrometry. The crystallinity index increased from 27% in the raw fiber to 40% after all treatments because of the removal of non-crystalline regions of cellulose and extracted material. Thermogravimetric analysis revealed no significant differences in the thermal stability of untreated and treated fibers. Elongation at break was the lowest for AT and HT, and the highest for ST. Removing silica bodies from the OPMF surface can benefit applications where surface properties are critical, adding value to the waste. As far as it is known, the approach used in this study is unprecedented.

This study assessed the role of conductive media as the main stimulant of electroactive organisms development during anaerobic self-regulation stress conditions. Thus, two structured bed anaerobic reactors fed with carbohydrate solution were compared: Reactor 1 (R1), which had a structured bed made of nylon granules (NG), and Reactor 2 (R2), which had a structured bed made of granular activated carbon (GAC). Both reactors were inoculated with extremal low inoculum content (0.05 % v:v) and operated under recirculation stages (batch stages). Thresholds of 80 % for the influent COD consumption and 15 % of COD conversion to CH4were defined as criteria to stop recirculation mode repetition and start continuous operation with the same input COD (continuous stages). In the three batch recirculation stages, R2 was able to reverse the acidogenic stress aided by GAC presence, reaching higher CH4production yield 2-fold then R1. R2 provided a methanogenic conversion around 18 % higher than R1 during the change of operation to continuous mode under unstable conditions transition. Analysis of the microbial community composition revealed a greater content of electroactive organisms belonging to the Geobacteraceae and Sphaerochaetaceae families in the GAC-bed. A shift for metabolic routes based on direct interspecies electron transfer was mostly likely a key factor for the reactor R2's greater ability to handle high acetogenic loads. Hence, stress conditions had a selective effect on the organisms, stimulating more electrogenic microbiomes in GAC-bed than in NG-bed.

CEASAs (wholesaler food supply centers) are strategically located throughout the Brazilian territory. However, food circulation leads to a high generation of fruit and vegetable waste. CEASA-Maracanaú (Ceará state, Brazil) is an example of this, sending around 17 tons of organic waste to the landfill each day without categorization. An environmentally friendly option to reuse fruit and vegetable wasted (FVW) at CEASA-Maracanaú is using it as a substrate in methane production through anaerobic digestion, which requires a detailed quality and quantity characterization. This study aimed to characterize the FVW generated at CEASA-Maracanaú to evaluate its biomethane potential and estimate energy recovery. To characterize the residue, questionnaires were sent to 1,200 permit holders. The results pointed to a residue composed of orange (42.0%), onion (7.7%), corn (5.5%), papaya (5.4%), avocado (4.8%), watermelon (3.4%), banana (3.0%), melon (3.1%), potato (3.0%), pineapple (3.1%), cabbage (2.4%), guava (1.2%), and tomato (1.0%), among others. This composition was crushed and characterized in terms of chemical oxygen demand (138.13?±?12.4 gCOD/kgFVW). Biomethane potential tests of crushed residue was 275 NmLCH4/gCOD or 313 NmLCH4/gVS, resulting in 79.3% biodegradability. From this potential, it is estimated that FVW from CEASA-Maracanaú yields a methane-based energy recovery of up to 373 KW of thermic power. As a result, it is possible to meet 86% energy demand of CEASA-Maracanaú during the rush-hour (5:30 pm to 8:30 pm) rate by employing the energy recovered from the daily accumulated biogas.

Biogas is one of the most promising renewable fuels for application in decentralized energy generation. In this context, gasoline-fueled spark ignition-based engines converted using commercial kits to run as flexible-fuel engines appear to be a low-cost alternative propulsion system. Therefore, this study aims to experimentally evaluate the performance parameters of a biogas-fueled generator set equipped with technology that has already diffused within society. The system comprises a 2.0-L petrol engine coupled to a synchronous generator, the power output, in-cylinder pressure and temperature, stability, and emission data of which were evaluated. The apparatus runs with biogas samples composed of CH4, C2H6, N2, CO2, and traces of other gases, of which the CO2concentrations vary by up to 14%. The results show that adjusting the ignition timing for an intermediate configuration makes it possible to achieve a flexible fuel engine. In addition, the injection of CO2into fuel allows an effective reduction of NOxemissions, although with slight decrease in performance. The efficiency decreases with an increase in the CO2concentration. With 14% CO2, combustion ends at 75.66º on average, which contrasts with other average gaseous fuel combustion endings at 64.05º. Under such operation conditions, the in-cylinder temperature and NOxemission are approximately 1442.91 K and 271.47 ppm. Finally, with CNG, the in-cylinder temperature and NOxemissions are 1758.53 K and 1963.25 ppm on average.