Experimental methods in chemical engineering: specific surface area and pore size distribution measurements—BET, BJH, and DFT

Review of biochar for the management of contaminated soil: Preparation, application and prospect.

As a class of famous carbon materials, biochars (BCs) and their derivative materials with excellent physicochemical properties and diversified functionalities present great potential in wastewater treatment fields. This review focuses on the latest development in reported biochar-based materials as superior adsorbents or catalysts for removing harmful organic contaminants from wastewater. The construction and properties of biochar-based materials are briefly introduced at the beginning. As one of the major factors affecting the properties of BCs, the wide diversity of feedstocks, such as agricultural and forest residues, industrial by-products as well as municipal wastes, endows BCs different chemical compositions and structures. Woody and herbaceous BCs usually have higher carbon contents, larger surface areas and strong aromaticity, which is in favor of the organic contaminant removal. Driven by the desire of more cost-effective materials, several types of biochar-based hybrid materials, such as magnetic BC composites (MBC), nanometal/nanometallic oxides/hydroxide BC composites and layered nanomaterial-coated BCs, as well as physically/chemically activated BCs, have also been developed. With the help of foreign materials, these types of hybrid BCs have excellent capacities to remove a wide range of organic contaminants, including organic dyestuff, phenols and chemical intermediates, as well as pharmaceutically active compounds, from aquatic solutions. Depending on the different types of biochar-based materials, organic contaminants can be removed by different mechanisms, such as physical adsorption, electrostatic interaction, π–π interaction and Fenton process, as well as photocatalytic degradation. In summary, the low cost, tunable surface chemistry and excellent physical–chemical properties of BCs allow it to be a potential material in organic contaminant removal. The combination of BCs with foreign materials endows BCs more functionalities and broader development opportunities. Considering the urgent demand of practical wastewater treatment, we hope more researches will focus on the applications and commercialization of biochar-based materials.

Biochar-based materials and their applications in removal of organic contaminants from wastewater: state-of-the-art review

Pb(II) uptake onto nylon microplastics: Interaction mechanism and adsorption performance.

Effects of modification and magnetization of rice straw derived biochar on adsorption of tetracycline from water.

The objective of this paper was the investigation of steam activation and mild air oxidation of biochar produced by using the Pyrovac Inc. vacuum pyrolysis for a biomass feedstock composed of a 20% volume fraction of (spruce and fir) with pine (stem of Pinus strobus without bark), with a moisture mass fraction of 10%. The biochar was activated at 900 °C under a steam partial pressure of 53 kPa over 60 min. The steam activated sample was then submitted to a mild oxidation process through a reactor fed with 164 cm3 min−1 of air at 200 °C under 100 kPa total pressure for 60 min. Biochar was also submitted to this mild oxidation process under the same conditions except for the oxidation time which was either 30 or 60 min. The samples were analyzed using techniques including proximate and elemental analysis, Brunauer-Emmett-Teller (BET) analysis for surface area and pore size distribution by non-local density functional theory (NLDFT), scanning and transmission electron microscopy (SEM/EDX and TEM), Boehm titration, Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). The BET surface area was increased from 50 to 1025 m2 g−1 upon steam activation while the concentration of functional groups was extensively decreased. Upon mild air oxidation, the concentration of functional groups in biochar was increased from 44 to 104.6 μmol m−2 in oxidized biochar. Combined elemental analysis and XPS results indicated that mild air oxidation generated a more uniform spatial distribution of oxygenated functional groups than in the biochar.

Steam activation and mild air oxidation of vacuum pyrolysis biochar

The effect of biochar mild air oxidation on the optimization of lead(II) adsorption from wastewater.

Film-Pore-[Concentration-Dependent] Surface Diffusion model for heavy metal ions adsorption: Single and multi-component systems

Catalytic hydrogenation of aldehydes is required as the stabilizing step in bio-oils conversion. Ruthenium supported on carbon was used in the present work for hydrogenation of furfural (FF) to furfuryl alcohol (FA). Converting a biochar with no surface area and low carboxyl groups surface density to an outstanding catalyst support using a very simple mild air/steam oxidation is the original contribution of this work. The mildly oxidized biochar is impregnated with a targeted loading of 2.5 wt.% Ru via ion-exchange, using Ru(NH3)6Cl2 precursor. ICP analysis shows that the mild oxidation increases Ru adsorption capacity of untreated biochar from 1.2 to 2.2 wt.%. H2 chemisorption and TEM analysis indicate that the preliminary mild oxidation leads to higher Ru dispersion. XPS analysis also shows that the treatment prevents Ru from surface segregation. The highest value of 93% FA selectivity at 53% FF conversion was obtained in a batch autoclave reactor under optimized conditions.

https://www.mdpi.com/2073-4344/10/8/934/pdf

Raoof Bardestani

Papers

Experimental methods in chemical engineering: specific surface area and pore size distribution measurements—BET, BJH, and DFT

Steam activation and mild air oxidation of vacuum pyrolysis biochar

The effect of biochar mild air oxidation on the optimization of lead(II) adsorption from wastewater.

Film-Pore-[Concentration-Dependent] Surface Diffusion model for heavy metal ions adsorption: Single and multi-component systems

Hydrogenation of Furfural to Furfuryl Alcohol over Ru Particles Supported on Mildly Oxidized Biochar