Activated biochars derived from wood biomass liquefaction residues for effective removal of hazardous hexavalent chromium from aquatic environments

Abstract

Residues obtained after wood biomass liquefaction were used as precursors for the synthesis of two activated biochars. The source of biomass liquefaction constituted of industrial wood processing by‐products, including bark and wood sawdust. The liquefied residues were analyzed in terms of chemical components and structure. Carbonization under nitrogen atmosphere followed by physical CO2 activation allowed to obtain microporous activated carbons with specific surface areas of 741 and 522 m2 g−1, and micropore volumes of 0.38 and 0.27 cm3 g−1, respectively. The obtained activated carbons were used to remove toxic hexavalent chromium from the aquatic environment. The observed sorption capacities were 80.6 mg g−1 versus 36.7 mg g−1 for wood bark‐derived and wood sawdust‐derived carbon, respectively, indicating a key role of the wood residue source in the effectiveness of Cr(VI) removal by resulting carbons. Despite the dominant microporous structure, the adsorption kinetics was surprisingly fast, especially for the bark‐derived carbon, since the adsorption equilibrium was reached within 2 h. The sorption mechanism of chromium was based on the carbon surface‐mediated reduction of toxic hexavalent form to its non‐toxic trivalent form, as confirmed by the X‐ray photoelectron analysis. Therefore, the residues from wood liquefaction can be easily converted into porous activated biocarbons capable of adsorbing significant amounts of hazardous Cr(VI) while reducing them to non‐toxic Cr(III).

Carbon-Based Nanocatalysts (CnCs) for Biomass Valorization and Hazardous Organics Remediation

“…On the regards of environmental remediation applications, other kind of carbonaceous materials, especially based on porous carbon or/and biochar, was shown to have ultimately high adsorptive capability against not only organic pollutants, but also against (heavy) metals [ 161 , 162 ]. The recent trend on materials design is to utilize undesired biomass and wastes as feedstock and after thermal treatment (carbonization) or/and activation to obtain bulky carbons/biochars [ 20 , 163 , 164 , 165 ] with the ultimate goal of the final material to possess high surface chemistry heterogeneity, high porosity and ultimately a micro-/nano-porous nature [ 12 , 13 ].…”

Diamine Groups on the Surface of Silica Particles as Complex-Forming Linkers for Metal Cations

“…Limited mining possibilities and the increasing costs for various metals, such as copper, nickel, and europium [6][7][8], mean that the prospect of their recovery from industrial waters and wastewater as well as deposited wastes seems to be a promising strategy to meet the growing demand for these heavy metals. Sorption is considered to be one of the Molecules 2023, 28, 430 2 of 20 most desired approaches for recovering various metals from industrial and natural waters because of its effectiveness, ease of use, low cost, and environmental sustainability [9]. The development and application of adsorption processes is always considered along with the development of new adsorbents with well-developed porous structures, large surface areas, and high contents of functional groups [10].…”

Modeling the Liquid Fuel Desulfurization Efficiency of Activated Carbons before and after Chemical Treatment: The Competitive Role of Mono- and Diaromatics

“…Its ease of operation, low cost, and environmental sustainability (since there is no demand for additives or energy-consuming steps and requirement for severe operating conditions) render ADDS as a highly promising process for the selective adsorption of the low-concentration aromatic organosulfur molecules, aiming to supplement or even replace conventional HDS. , A wide range of materials have been widely studied as adsorbents for ADDS, namely, carbon-based materials, zeolites, mesoporous silicas, metal organic frameworks, alumina, and metal oxides. ,− Activated carbons, and especially the nanoporous ones, are considered among the most appropriate and efficient candidates for the deep desulfurization of fuels. This is due to their tunable specific physicochemical features (large specific surface area, pore volumes, and surface chemistry heterogeneity), considerably cheap nature and potentiality to be obtained from biomass and (bio)­wastes, in addition to their regeneration ability. , Another important aspect is that their surface chemistry features can be easily modified on demand (i.e., chemical treatment with acid or the addition of heteroatoms on the surface, like iron) in order for specific desirable surface functionalities to be introduced. ,,− …”

“…This is due to their tunable specific physicochemical features (large specific surface area, pore volumes, and surface chemistry heterogeneity), considerably cheap nature and potentiality to be obtained from biomass and (bio)wastes, in addition to their regeneration ability. 20,21 Another important aspect is that their surface chemistry features can be easily modified on demand (i.e., chemical treatment with acid or the addition of heteroatoms on the surface, like iron) in order for specific desirable surface functionalities to be introduced. 14,18,22−25 Activated porous carbons have been studied as adsorbents for the removal of several thiophenic compounds (i.e., TH, DBT, 4,6-DMDBT) from organic solvents and/or model fuels, although the number of articles regarding real fuels and the copresence of other compounds and especially aromatics are limited.…”