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Research on the use of sustainable fillers which promote improvements in the paints has been reported over the years. The present study investigated the production and characterization of a biochar produced from Pinus elliottiifor application in an epoxy paint cured by ultraviolet radiation, comparing it with graphite, in proportions of 12.5 and 20 wt%. The Pinus elliottiisample was initially ground, and then submitted to physical and morphological characterization by field emission scanning electron microscopy (SEM) and X-ray diffraction (XRD). Later, the Pinus elliottiisample was subjected to pyrolysis at a temperature of 1050°C at a low heating rate (5°C/min). Biochar and graphite were separately incorporated into an epoxy UV-curable paint. The painted samples had their thickness measured and their mechanical and physical properties evaluated, namely gloss, hardness, bending, impact, contact angle with water, and exposure to salt spray. Biochar and graphite promoted a reduction in gloss and improved pencil hardness when incorporated into a UV-curable epoxy paint. In the salt spray resistance test, samples containing both biochar and graphite showed a slight delay in the beginning of the corrosion process. However, samples with biochar behaved better than samples with graphite in terms of blistering of the film in the incision region.

Based on cleaner production and circular economy concepts, chars were produced through thermochemical conversion of grape bagasse and then used as adsorbents to uptake Cu(II) from aqueous media since Cu(II) is a common element found in fungicides to treat grapevines. The grape bagasse and char characteristics were investigated through several analytical techniques (TGA, SEM, XRD, FTIR, and BET). Three chars were obtained using different pyrolysis temperatures: 700, 800, and 900 °C. The materials had similar removal percentages and adsorption capacity. The char produced at 700 °C was chosen due to its lower production cost. Studies were conducted on the adsorbent dosage and pH effect, adsorption kinetics, isotherms, and thermodynamics. The most efficient dosage was 1.5 g L−1, and the pH was 5.5. The kinetic study showed that the equilibrium was reached in 60 min and the pseudo-second-order model presents the best fit. After the temperature influence study (25, 35, 45, and 55 °C), it was possible to verify that Cu(II) adsorption through char was favored at 55 °C. The Freundlich model showed the best fit for the experimental data. The highest removal percentage was 96.56%, and the high maximum adsorption capacity was 42 mg g−1. The thermodynamic study shows the adsorption as a spontaneous process, favorable, and endothermic.

The objective of this work was to characterize and study the behavior of the adsorption process of cellulose/biochar cryogels through isotherm models and adsorption kinetics. The cryogels were produced from a cellulose suspension obtained by mechanical fibrillation of 0.75 and 1.5% w/w unbleached long-fiber cellulose of the Pinus elliottispecies. Into this suspension, 5, 10, and 20% w/w (relative to cellulose mass) biochar were added; then, the suspension was frozen and freeze-dried. After this, 2 mL of methyltrimethoxysilane (MTMS) was deposited on the cryogels. Characterization analyses were performed on the cryogels, including specific mass and porosity and sorption capacity, in addition to the study of adsorption kinetics and isotherms. The cryogels showed a porosity of above 90% and a specific gravity of less than 0.035 g cm–3. The heterogeneous sorption capacity varied according to the concentration of cellulose used, and with the addition of 5% w/w biochar in the cellulose cryogel, the highest sorption capacity was obtained, 73 g g–1of petroleum and 54 g g–1of SAE20W50 oil. In the study of adsorption isotherms, the Freundlich model best fitted the process. Therefore, it was concluded that the process of petroleum adsorption by the cellulose cryogel occurs in multiple layers. In addition, the cellulose/biochar cryogel developed in the present work is suitable for use in the adsorption of organic liquids.

The products obtained through thermal conversion of tyres can represent a solution for its disposal which has been considered an environmental problem. In the foundry industry two types of sand are generated: core sand (CS) and green sand (GS); CS is classified as hazardous waste. In this paper two kinds of industrial wastes were approached, in order to propose a solution through co-pyrolysis. The experiments were performed in a bubbling fluidized bed reactor. The oil, fuel gas and char obtained were characterized. The main components present in the oil were naphthalene and anthracene. Char morphology was assessed by Scanning Electron Microscopy, confirming the resin absence on its surface. Isothermal adsorption and desorption indicated that the char obtained from tyre pyrolysis with lower particles has higher superficial area (higher than 200 m2·g-1). The main compounds identified in fuel gas were hydrogen, carbon monoxide, carbon dioxide and hydrocarbons up to 5 carbons.

In this work, a high porous activated carbon from Jacaranda mimosifoliawas developed and employed for ketoprofen adsorption. After the pyrolysis process at 973.15 K, the material presented cavities with different sizes allocated on the particle surface. The material presented a pH at the point of zero charge of 4.1 with the best adsorption at pH 2. The best adsorbent dosage was 0.72 g L−1, corresponding to a removal of 96%. The system reached the adsorption equilibrium after 120 min and was described by the linear driving force model. The isotherms revealed that the adsorption capacity decreased with the temperature and followed the Langmuir model, with a maximum adsorption capacity of 303.9 mg g−1. This high capacity can be associated with the high surface area (928 m2g−1) and pore volume (0.521 cm3g−1) values. The thermodynamic values indicated that the adsorption system is spontaneous and exothermic. The enthalpy value indicates that the interactions between the adsorbent and adsorbate are physical. Regeneration tests showed a decreasing percentage of removal of 7.86% after 5 cycles. Finally, the adsorbent showed efficiency when treating a simulated effluent containing drugs and inorganic salts, showing the removal of 71.43%.

•Biochars were produced from malt bagasse by activation with CO2and ZnCl2.•The materials were used to treat effluents containing 2-chlorophenol.•Biochars presented surface areas of 161 m² g−1(CO2) and 545 m² g−1(ZnCl2).•ZnCl2-biochar exhibited an efficiency of 98 % in the treatment of effluents.