Search results for "aktiivihiili"
showing 10 items of 20 documents
Catalytic conversion of glucose to 5-hydroxymethylfurfural over biomass-based activated carbon catalyst
2020
Selective and efficient dehydration of glucose to 5-hydroxymethylfurfural (HMF) has been widely explored research problem recently, especially from the perspective of more sustainable heterogeneous catalysts. In this study, activated carbon was first produced from a lignocellulosic waste material, birch sawdust. Novel heterogeneous catalysts were then prepared from activated carbon by adding Lewis or Brønsted acid sites on the carbon surface. Prepared catalysts were used to convert glucose to HMF in biphasic water:THF system at 160 °C. The highest HMF yield and selectivity, 51% and 78%, respectively, were obtained in 8 h with a catalytic mixture containing both Lewis and Brønsted acid sites…
Study of Ni, Pt, and Ru Catalysts on Wood-based Activated Carbon Supports and their Activity in Furfural Conversion to 2-Methylfuran
2018
Bio‐based chemicals can be produced from furfural through hydrotreatment. In this study, 2‐methylfuran (MF), a potential biofuel component, was produced with Pt, Ru, and Ni catalysts supported on wood‐based activated carbons. The catalytic hydrotreatment experiments were conducted in a batch reactor at 210–240 °C with 2‐propanol as solvent and 40 bar H2 pressure. Two types of activated carbon supports were prepared by carbonization and activation of lignocellulosic biomass (forest‐residue‐based birch and spruce from Finland). Both types of activated carbons were suitable as catalyst supports, giving up to 100 % furfural conversions. The most important factors affecting the MF yield were the…
Carbons from second generation biomass as sustainable supports for catalytic systems
2018
In this study activated carbons were produced from the wood of three different wood species (pine, birch, spruce). The resulting activated carbons were characterized in bulk for ash content, carbon content (elemental analyses), specific surface area, and pore size distribution, and at the surface by measuring the autogenerated pH and studying their structure by XPS. All the samples presented high surface areas and appeared to be mesoporous materials (mesopores >80%). The carbons were then used as support for AuPt nanoparticles and tested in the liquid phase oxidation of glycerol (GLY) and in the hydrogenation of levulinic acid (LA), two important chemicals from cellulose-based biomass. The …
Development of iron oxide/activated carbon nanoparticle composite for the removal of Cr(VI), Cu(II) and Cd(II) ions from aqueous solution
2018
Iron oxide (Fe3O4) and iron oxide/activated carbon (Fe3O4/AC) were fabricated by co-precipitation method for the removal of Cr(VI), Cu(II) and Cd(II) ions from aqueous solution in batch mode. These nanoparticles were characterized by BET, FTIR, XRD, SEM/TEM and VSM. The optimum conditions for the removal of ions were pH = 2 for Cr(VI) and 6 for Cu(II) and Cd(II), initial metal ion concentration = 50 mg L−1, nanoparticle dose = 50 mg/10 mL, temperature = 25 ± 1 °C, shaking speed = 180 rpm and contact time = 3 h. The equilibrium data of ions sorption were well described by Langmuir, Freundlich, Redlich-Peterson and Intraparticle Diffusion model. The R2 values obtained by Langmuir model were h…
Effects of activated carbon ageing in three PCB contaminated sediments: Sorption efficiency and secondary effects on Lumbriculus variegatus.
2015
The sorption efficiency and possible secondary effects of activated carbon (AC) (o 63-200 μm) was studied with Lumbriculus variegatus in three PCB contaminated sediments applying long AC-sediment contact time (3 years). AC amendment efficiently reduced PCB bioavailability as determined with both, L. variegatus bioaccumulation test and passive samplers. However, dose related secondary effects of AC on egestion rate and biomass were observed (applied doses 0.25% and 2.5% sediment dry weight). The sorption capacity and secondary effects remained similar when the experiments were repeated after three years of AC-sediment contact time. Further, transmission electron microscopy (TEM) samples reve…
Activated Cashew Carbon-Manganese Oxide Based Electrodes for Supercapacitor Applications
2023
The current global energy challenge which affects most developing countries in particular, is of major source of concern today. The availability of less expensive techniques of storing excess generated energy is critical to the success of the renewable energy roadmaps implementation. In this study, hydrothermal and chemical leaching methods have been used to synthesize MnO2 nanoparticles using KMnO4 and MnSO4 as precursors at 140 °C and from natural local manganese ore. Activated Carbon (ACF) have also been produced from agricultural Cashew biomass waste, through a physical carbonization and KOH activation process using temperatures of 700 °C – 900 °C for periods between 1-2 hours. The as-p…
Biomass-based composite catalysts for catalytic wet peroxide oxidation of bisphenol A:preparation and characterization studies
2019
The wet granulation process was used to prepare new, efficient, and cost-effective granular biomass-based composite catalysts for catalytic wet peroxide oxidation (CWPO) of bisphenol A (BPA). The most stable composite granules was prepared by mixing biomass-based carbon residue (CR) with metakaolin (MK) combined with calcium oxide (CaO) or cement and a solvent (NaOH or KOH). For all the prepared composite granules, the optimized binding agents to carbon ratio was 0.3, the solvent to carbon ratio 1.2, and the agitation rate 1200 rpm. The specific surface area of the prepared catalysts was 152–205 m2/g. The composite granular catalyst (CR + MK + CaO + NaOH) had the most durable and stable str…
Biomass-based composite catalysts for catalytic wet peroxide oxidation of bisphenol A : preparation and characterization studies
2019
Abstract The wet granulation process was used to prepare new, efficient, and cost-effective granular biomass-based composite catalysts for catalytic wet peroxide oxidation (CWPO) of bisphenol A (BPA). The most stable composite granules was prepared by mixing biomass-based carbon residue (CR) with metakaolin (MK) combined with calcium oxide (CaO) or cement and a solvent (NaOH or KOH). For all the prepared composite granules, the optimized binding agents to carbon ratio was 0.3, the solvent to carbon ratio 1.2, and the agitation rate 1200 rpm. The specific surface area of the prepared catalysts was 152–205 m2/g. The composite granular catalyst (CR + MK + CaO + NaOH) had the most durable and s…
Development of iron oxide / activated carbon nanoparticle composite for the removal of Cr(VI), Cu(II) and Cd(II) ions from aqueous solution
2018
Iron oxide (Fe3O4) and iron oxide/activated carbon (Fe3O4/AC) were fabricated by co-precipitation method for the removal of Cr(VI), Cu(II) and Cd(II) ions from aqueous solution in batch mode. These nanoparticles were characterized by BET, FTIR, XRD, SEM/TEM and VSM. The optimum conditions for the removal of ions were pH = 2 for Cr(VI) and 6 for Cu(II) and Cd(II), initial metal ion concentration = 50 mg L−1, nanoparticle dose = 50 mg/10 mL, temperature = 25 ± 1 °C, shaking speed = 180 rpm and contact time = 3 h. The equilibrium data of ions sorption were well described by Langmuir, Freundlich, Redlich-Peterson and Intraparticle Diffusion model. The R2 values obtained by Langmuir model were h…
Ibuprofen degradation using a Co-doped carbon matrix derived from peat as a peroxymonosulphate activator
2021
The wider presence of pharmaceuticals and personal care products in nature is a major cause for concern in society. Among pharmaceuticals, the anti-inflammatory drug ibuprofen has commonly been found in aquatic and soil environments. We produced a Co-doped carbon matrix (Co-P 850) through the carbonization of Co2+ saturated peat and used it as a peroxymonosulphate activator to aid ibuprofen degradation. The properties of Co-P 850 were analysed using field emission scanning electron microscopy, energy filtered transmission electron microscopy and X-ray photoelectron spectroscopy. The characterization results showed that Co/Fe oxides were generated and tightly embedded into the carbon matrix …