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• Environmentally friendly fertilizer and activated carbon were produced from these two waste products. • The production procedure is a one-step process involving no chemicals. • Obtaining fertilizer products from residual materials is important in terms of resource protection. • These wastes contain economic and environmental added values as they are sustainable sources. • It is of higher quality and lower-cost than its chemical substitutes. This study investigated the production conditions of a potassium magnesium phosphate fertilizer with vinasse (a by-product of the sugar or ethanol industry) and grape marc (a by-product of the wine-making industry). A mixture of vinasse and grape marc was subjected to pyrolysis under a nitrogen gas atmosphere, and water was used to extract potassium from the end product. Potassium magnesium phosphate (potassium-struvite, KMgPO 4.6H 2 O), a slow-release fertilizer compound, was obtained from the extract with potassium to explore process conditions and product characteristics. Producing fertilizer products from residual materials is of paramount significance for conserving natural resources. The mixture was pyrolyzed, allowing us to remove potassium from the complex matrix of concentrated vinasse to a clear and high alkaline solution. The residual carbon was activated by decomposing (pyrolysis) and treating the residue and then washing it with water. The extract had high alkalinity, suggesting that the potassium in the mixture resulted in carbon activation during biomass pyrolysis. Pyrolysis and treatment can be used to produce activated carbon from vinasse. This study also investigated the solubility of vinasse in water and aqueous solutions. K-struvite with 10.67 % K 2 O was about 2% soluble in water, indicating that the end product was a slow-release fertilizer agent. In conclusion, this process can be used to produce potassium (a slow-release fertilizer) and activated carbon (a by-product) from vinasse for different purposes. [ABSTRACT FROM AUTHOR]

In the present work, an activated carbon obtained as by-product in a fertilizer preparation process was studied for Cr(VI) adsorption from aqueous solutions. Batch adsorption experiments were carried out by varying the pH, initial Cr(VI) concentration, contact time, activated carbon dosage and temperature. The adsorption of Cr(VI) was found to be highly pH-dependent and maximum adsorption was observed in the acidic pH range. Equilibrium data were applied to Langmuir, Freundlich, and D-R adsorption isotherms. Also, kinetic data were analyzed for pseudo-first, pseudo-second, and intraparticle diffusion models. Langmuir adsorption isotherm and pseudo-second kinetic model were fit best to the related data. Maximum adsorption capacity was found to be 74.63 mg/g at the conditions of the temperature of 25 °C, the pH of 3.5, the contact time of 360 min and the adsorbent dosage of 1 g/L. Activation energy, mean adsorption energy (from D–R isotherm) and thermodynamic parameters were evaluated and nature of the adsorption process was found to be as physical, endothermic, and spontaneous. The potassium-removed char was washed with an acid solution and then characterized as AC. AC was obtained as a by-product and its Cr(VI) adsorption efficiency was determined. This study aimed to use AC as an adsorbent with relatively favorable surface properties for the removal of heavy metals from wastewaters. A slow released potassium fertilizer and an activated carbon were obtained from two waste materials in such a process. This novel active carbon having relatively favorable surface properties was considered to be utilized as an adsorbent in Cr(VI) removal from aqueous solutions. [ABSTRACT FROM AUTHOR]

Activated carbon was prepared from commercial polyurethane and polymer waste by chemical activation using zinc chloride. The prepared activated carbon was characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface analysis, elemental analysis, iodine number, surface functional groups, the pH of zero point charge (pHzpc), and the moisture and ash contents. The experimental parameters of pH, temperature, initial concentration, and adsorbent dosage were optimized for the removal of Cu (II) from aqueous solution. The adsorption mechanism for the removal of Cu(II) from aqueous solution by the activated carbon obtained from waste polyurethane by zinc chloride activation was characterized using pseudo-first order, pseudo-second order and intraparticle diffusion models, Fourier transform infrared spectroscopy, and SEM. These experiments were performed under the optimum conditions obtained using response surface methodology (RSM). The optimum conditions for pH, temperature, concentration, and adsorbent dosage were 5.7, 53 °C, 27 mg/L, and 4.2 g, respectively. The results were analyzed using isotherm and kinetic models. The highest monolayer adsorption capacity of Cu (II) ions onto the activated carbon was 31.95 mg/g. The pseudo-second order kinetic model was the ideal model. Approximately 80% of Cu (II) was removed from the solution. [ABSTRACT FROM AUTHOR]

• An activated carbon was produced from wine stone, which is a waste product. • It has high porosity and surface area, and contains hydroxyl and carboxyl groups. • It is of higher quality and lower-cost than its chemical substitutes. • The production procedure is a one-step process which involves no chemicals. Alkaline potassium compounds such as K 2 CO 3 and KOH are chemical activators used to produce activated carbons (ACs). The substance, known as wine stone or cream of tartar and formed in wine fermentation tanks during wine production from grape juice concentrates, consists of potassium hydrogen tartrate (KHC 4 H 4 O 6). Highly porous carbons with various textural characteristics were obtained from organic wine stone subjected to simple heat-treatment. This procedure is a one-step carbonization treatment performed at different carbonization temperatures (400 and 900 °C) and times (15 and 360 min), and nitrogen flow rates (100 and 600 ml/min). The chemical and physical properties of AC were examined using SEM-EDX, FT-IR analysis, particle size distribution, iodine number, pHpzc, BET surface area, surface functional group analysis by the Boehm's titration. BET surface area, total pore volume, average pore diameter, iodine number, pHzpc and carbon content were 1814.6 m2 g−1, 0.7767 cm3 g−1, 18.2 Å, 1986.4 mg g−1, 6.18 and 92.96%, respectively. Pore size, surface area and pore volume increased with an increase in carbonization temperature, and AC surface had high porosity and acidic functional groups. A promising approach focusing on the use of potassium-enriched properties of wine stone for easy and environmentally friendly production of activated carbons is emphasized. [ABSTRACT FROM AUTHOR]

• Effects of the AC modification on the rheological characteristics of the bitumens were examined. • HMA properties including the activated carbon modified binders were investigated. • Activated carbon increased stiffness and high temperature resistance of bituminous binder. • AC improved stability, stiffness, resistance against the fatigue cracking, and permanent deformation of mixes. • Using AC in the bitumen modification adversely affected the resistance against the moisture-induced damage in HMAs. This study examined the effect of the activated carbon, obtained from marc and vinasse agricultural wastes and used in the bitumen modification, on the rheological characteristics of bitumen binders and mechanical properties of hot mix asphalt. For this purpose, the activated carbon, obtained from vinasse generated at distillation step in the alcohol production from molasses together with grape marc, was used. The activated carbon was added to neat bitumen (PG 58–16) in 3 different ratios (5%, 10%, and 15% by weight of neat binder). The following tests were applied to the neat and modified bitumen: BBR (bending beam rheometer), DSR (dynamic shear rheometer), rotational viscosity, softening point, and penetration. The HMA samples were prepared using the neat and modified binders. The following tests were applied to the HMA samples: Marshall stability and flow, resistance against the damage induced by moisture, indirect tensile stiffness modulus, cyclic creep, and indirect tensile fatigue. Considering the binder test results, it was determined that using the activated carbon in the bituminous modification increased the stiffness and high-temperature performance of the bituminous binders, while the low-temperature performance was not affected much. Based on the mixture tests, it was found that using the activated carbon modified bitumen increased the Marshall stability, stiffness, resistance against the fatigue cracking, and permanent deformation of mixes. On the other hand, the use of activated carbon in bitumen modification adversely affected the resistance against the moisture-induced damage. [ABSTRACT FROM AUTHOR]