Evaluation of torrefied poplar-biomass as a low-cost sorbent for lead and terbium removal from aqueous solutions and energy co-generation

Abstract

Two low-cost renewable poplar-based materials were manufactured in this work for energy production and as sorbents for lead and terbium removal from aqueous effluents. Torrefaction was used as a pretreatment process for conditioning the raw biomass. Two different operating conditions were used in the multiple-hearth furnace of the torrefaction pilot-plant: i) 250°C; ii) 280°C, with residence times of 75 min and 60 min, respectively. The raw and torrefied biomasses have been characterized using SEM-EDX, FTIR, TGA, XRD and elemental analyses (C, H, N, S, O); an increase of the torrefaction severity, results in an increase of the carbon/oxygen ratio and in a greater mass loss (21% at 250°C, and 53% at 280°C). The torrefaction had a positive impact on the sorption of metals, it allowed the increase of lignin content of the manufactured materials, and it allowed the storage of the sorbents for longer time with reduced moisture content. The equilibrium studies were performed in batch system and the experimental data were described with the Sips equation. The maximum sorption capacity was found as 30 mg g −1 for lead and 9.4 mg g −1 for terbium (at pH 4). The kinetic profiles were fitted using the pseudo-second order rate equation. The regeneration of the sorbent was demonstrated by three sorption-desorption cycles using dilute HNO 3 solution (0.1 M) as eluent for metal recovery.

Preparation of Activated Biochar-Supported Magnetite Composite for Adsorption of Polychlorinated Phenols from Aqueous Solutions

“…In the past decades, several efficient ways to treat wastewater containing organic and inorganic pollutants have been considered as one of the important topics in environmental science [1][2][3][4][5]. Chlorinated organic compounds (e.g., dioxins, polychlorophenols) are known as significant environmental pollutants, because these compounds have great resistance to biological degradation processes and affect serious health problems (e.g., nervous or respiratory systems) via the bioaccumulation of organisms in the ecosystem [6].…”

Acid-Catalyzed Wet Torrefaction for Enhancing the Heating Value of Barley Straw

“…The optimal conditions for ACWT of barley straw were found. The polynomial equation used herein was as follows: HHV = 20.397 + 1.18A + 0.585B + 0.4138C + 0.2775AB − 0.38AC − 0.0575BC + 1.0967A 2 − 1.1008B 2 + 0.7367C 2 (10) By solving this model using a partial differential equation (PDE), three 3D graphs were developed.…”

“…Moreover, biomass disadvantages include heterogeneity in structure, low density, high humidity, low higher heating values (HHVs) and flexibility, all of which limit the use of biomass as a fuel [7,10]. These disadvantages make the production of heat and energy from biomass more complicated.…”

Application of a Low-Cost Cellulose-Based Bioadsorbent for the Effective Recovery of Terbium Ions from Aqueous Solutions

“…In the case of terbium, some adsorbents associated to its recovery from solutions included: 1-(2pyridylazo)-2-naphthol (PAN) doped hybrid silica [3], nanoporous calcium alginate/carboxymethyl chitosan microbiocomposite powder containing Ni0.2Zn0.2Fe2.6O4 magnetic nanoparticles [4,5], magnetic CMC bionanocomposite containing a novel biodegradable nanoporous polyamide [6], lignocellulosic biomass [7], calcium alginate/poly(pyrimidine-thiophene-amide) [8], graphite nanoplatelets/magnetite [9], hydroxyapatite/NiFe2O4 composite [10], torrefied poplar-biomass [11], nZVI-montmorillonite [12].…”