| 1. |
- dos Reis, Glaydson Simões, et al.
(författare)
-
Application of design of experiments (DoE) for optimised production of micro- and mesoporous Norway spruce bark activated carbons
- 2023
-
Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 13:11, s. 10113-10131
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, Norway spruce (Picea abies (Karst) L.) bark was employed as a precursor to prepare activated carbon using zinc chloride (ZnCl2) as a chemical activator. The purpose of this study was to determine optimal activated carbon (AC) preparation variables by the response surface methodology using a Box–Behnken design (BBD) to obtain AC with high specific surface area (SBET), mesopore surface area (SMESO), and micropore surface area (SMICR). Variables and levels used in the design were pyrolysis temperature (700, 800, and 900 °C), holding time (1, 2, and 3 h), and bark/ZnCl2 impregnation ratio (1, 1.5, and 2). The optimal conditions for achieving the highest SBET were as follows: a pyrolysis temperature of 700 °C, a holding time of 1 h, and a spruce bark/ZnCl2 ratio of 1.5, which yielded an SBET value of 1374 m2 g−1. For maximised mesopore area, the optimal condition was at a pyrolysis temperature of 700 °C, a holding time of 2 h, and a bark/ZnCl2 ratio of 2, which yielded a SMESO area of 1311 m2 g−1, where mesopores (SMESO%) comprised 97.4% of total SBET. Correspondingly, for micropore formation, the highest micropore area was found at a pyrolysis temperature of 800 °C, a holding time of 3 h, and a bark/ZnCl2 ratio of 2, corresponding to 1117 m2 g−1, with 94.3% of the total SBET consisting of micropores (SMICRO%). The bark/ZnCl2 ratio and pyrolysis temperature had the strongest impact on the SBET, while the interaction between temperature and bark/ZnCl2 ratio was the most significant factor for SMESO. For the SMICRO, holding time was the most important factor. In general, the spruce bark AC showed predominantly mesoporous structures. All activated carbons had high carbon and low ash contents. Chemical characterisation indicated that the ACs presented disordered carbon structures with oxygen functional groups on the ACs’ surfaces. Well-developed porosity and a large surface area combined with favourable chemical composition render the activated carbons from Norway spruce bark with interesting physicochemical properties. The ACs were successfully tested to adsorb sodium diclofenac from aqueous solutions showing to be attractive products to use as adsorbents to tackle polluted waters. Graphical abstract: [Figure not available: see fulltext.].
|
|
| 2. |
- dos Reis, Glaydson Simões, et al.
(författare)
-
Flexible supercapacitors of biomass-based activated carbon-polypyrrole on eggshell membranes
- 2021
-
Ingår i: Journal of Environmental Chemical Engineering. - : Elsevier. - 2213-3437. ; 9:5
-
Tidskriftsartikel (refereegranskat)abstract
- The quest to develop flexible membrane-like supercapacitors to be applied in advanced electronic devices with a flexible structure is important for the modern world. In this study, we developed biomass-based supercapacitors by depositing activated carbon on an eggshell membrane and subsequently coating these with polypyrrole in a two-step procedure. The competition between the electrical double layer capacitance (EDLC) from activated carbon and the pseudocapacitance (PC) for the hybrid device is controlled by varying the amount of polypyrrole (PC component) in a time-dependent polymerization process. An areal capacitance of 172.5 mF cm−2, a corresponding energy density of 4.73 W h kg−1, and power density of 320.8 W kg−1, with a 60% retention even after 1000 cycles were obtained for samples prepared with the polymerization of polypyrrole on the activated carbon (incorporation of an active layer of 3.18 mg cm−2).
|
|
| 3. |
- dos Reis, Glaydson Simoes, et al.
(författare)
-
Supercapacitors and triboelectric nanogenerators based on electrodes of greener iron nanoparticles/carbon nanotubes composites
- 2024
-
Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 14:1
-
Tidskriftsartikel (refereegranskat)abstract
- The development of supporting materials based on carbon nanotubes (CNTs) impregnated with iron nanoparticles via a sustainable and green synthesis employing plant extract of Punica granatum L. leaves was carried out for the iron nanoparticle modification and the following impregnation into the carbon nanotubes composites (CNT-Fe) that were also coated with polypyrrole (CNT-Fe + PPy) for use as electrode for supercapacitor and triboelectric nanogenerators. The electrochemical characterization of the materials by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) assays revealed that the CNT-Fe + PPy gave rise to better performance due to the association of double-layer capacitance behavior of carbon derivative in association with the pseudocapacitance contribution of PPy resulting in an areal capacitance value 202 mF/ cm2 for the overall composite. In terms of the application of electrodes in triboelectric nanogenerators, the best performance for the composite of CNT-Fe + PPy was 60 V for output voltage and power density of 6 μW/cm2. The integrated system showed that the supercapacitors can be charged directly by the nanogenerator from 0 to 42 mV in 300 s. The successful green synthesis of iron nanoparticles on CNT and further PPy coating provides a feasible method for the design and synthesis of high-performance SCs and TENGs electrode materials. This work provides a systematic approach that moves the research front forward by generating data that underpins further research in self-powered electronic devices.
|
|
| 4. |
- Ekman, Simon, et al.
(författare)
-
Synthesis, Characterization, and Adsorption Properties of Nitrogen-Doped Nanoporous Biochar : Efficient Removal of Reactive Orange 16 Dye and Colorful Effluents
- 2023
-
Ingår i: Nanomaterials. - : MDPI. - 2079-4991. ; 13:14
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, nitrogen-doped porous biochars were synthesized from spruce bark waste using a facile single-step synthesis process, with H3PO4 as the chemical activator. The effect of nitrogen doping on the carbon material’s physicochemical properties and adsorption ability to adsorb the Reactive Orange 16 dye and treat synthetic effluents containing dyes were evaluated. N doping did not cause an important impact on the specific surface area values, but it did cause an increase in the microporosity (from 19% to 54% of micropores). The effect of the pH showed that the RO-16 reached its highest removal level in acidic conditions. The kinetic and equilibrium data were best fitted by the Elovich and Redlich–Peterson models, respectively. The adsorption capacities of the non-doped and doped carbon materials were 100.6 and 173.9 mg g−1, respectively. Since the biochars are highly porous, pore filling was the main adsorption mechanism, but other mechanisms such as electrostatic, hydrogen bond, Lewis acid-base, and π-π between mechanisms were also involved in the removal of RO-16 using SB-N-Biochar. The adsorbent biochar materials were used to treat synthetic wastewater containing dyes and other compounds and removal efficiencies of up to 66% were obtained. The regeneration tests have demonstrated that the nitrogen-doped biochar could be recycled and reused easily, maintaining very good adsorption performance even after five cycles. This work has demonstrated that N-doped biochar is easy to prepare and can be employed as an efficient adsorbent for dye removal, helping to open up new solutions for developing sustainable and effective adsorption processes to tackle water contamination.
|
|
| 5. |
- González-Hourcade, María, et al.
(författare)
-
Microalgae biomass as a sustainable precursor to produce nitrogen-doped biochar for efficient removal of emerging pollutants from aqueous media
- 2022
-
Ingår i: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 348
-
Tidskriftsartikel (refereegranskat)abstract
- Preparing sustainable and highly efficient biochars as adsorbents remains a challenge for organic pollutant management. Herein, a novel nitrogen-doped carbon material has been synthesized via a facile and sustainable single-step pyrolysis method using a wild mixture of microalgae as novel carbon precursor. Phosphoric acid (H3PO4) was employed as activation agent to generate pores in the carbon material. In addition, the effect of melamine (nitrogen source) was evaluated over the biochar properties by the N-doping process. The results showed that the biochar's specific surface area (SSA) increased from 324 to 433 m2 g−1 with the N-doping process. The N-doping process increased the percentage of micropores in the biochar structure. Chemical characterization of the biochars indicated that the N-doping process helped to increase the graphitization process of the biochar and the contents of oxygen and nitrogen groups on the carbon surface. The biochars were successfully tested to adsorb acetaminophen and treat two synthetic effluents, and the N-doped biochar presented the highest efficiency. The kinetics and equilibrium data were well represented by the General-order model and the Liu isotherm model, respectively. The maximum sorption capacities attained were 101.4 and 120.7 mg g−1 for the non-doped and doped biochars, respectively. The acetaminophen adsorption mechanism suggests that the pore-filling was the dominant mechanism for acetaminophen uptake. The biochars could efficiently remove up to 74% of the contaminants in synthetic effluents.
|
|
| 6. |
- Grimm, Alejandro, et al.
(författare)
-
Adsorption of omeprazole on biobased adsorbents doped with Si/Mg: kinetic, equilibrium, and thermodynamic studies
- 2023
-
Ingår i: Molecules. - 1420-3049. ; 28
-
Tidskriftsartikel (refereegranskat)abstract
- This paper proposes an easy and sustainable method to prepare high-sorption capacity biobased adsorbents from wood waste. A biomass wood waste (spruce bark) was employed to fabricate a composite doped with Si and Mg and applied to adsorb an emerging contaminant (Omeprezole) from aqueous solutions, as well as synthetic effluents loaded with several emerging contaminants. The effects of Si and Mg doping on the biobased material’s physicochemical properties and adsorptive performance were evaluated. Si and Mg did not influence the specific surface area values but impacted the presence of the higher number of mesopores. The kinetic and equilibrium data presented the best fitness by the Avrami Fractional order (AFO) and Liu isotherm models, respectively. The values of Qmax ranged from 72.70 to 110.2 mg g−1 (BP) and from 107.6 to 249.0 mg g−1 (BTM). The kinetic was faster for Si/Mg-doped carbon adsorbent, possibly due to different chemical features provoked by the doping process. The thermodynamic data showed that the adsorption of OME on biobased adsorbents was spontaneous and favorable at four studied temperatures (283, 293, 298, 303, 308, 313, and 318 K), with the magnitude of the adsorption correspondent to a physical adsorption process (ΔH° < 2 kJ mol−1). The adsorbents were applied to treat synthetic hospital effluents and exhibited a high percentage of removal (up to 62%). The results of this work show that the composite between spruce bark biomass and Si/Mg was an efficient adsorbent for OME removal. Therefore, this study can help open new strategies for developing sustainable and effective adsorbents to tackle water pollution.
|
|
| 7. |
- Grimm, Alejandro, et al.
(författare)
-
Adsorptive behavior of the rare earth elements Ce and La on a soybean pod derived activated carbon: Application in synthetic solutions, real leachate and mechanistic insights by statistical physics modeling
- 2023
-
Ingår i: Chemical Engineering Journal. - 1385-8947. ; 471
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, we aimed to produce a sustainable and efficient powdered activated carbon (SP-AC) and evaluate its adsorptive abilities to uptake and recover rare earth elements (REEs) from synthetic solutions containing lanthanum (La(III)) and cerium (Ce(III)), and real leachate, from phosphogypsum, containing several REEs. The adsorbent material was subjected to several characterization techniques to understand its physicochemical and adsorptive properties. The characterization results indicated that the activated carbon prepared in this work possesses a specific surface area, pore volume, and average pore diameter of 614 m2g-1, 0.121 cm3g-1, and 3.65 nm, respectively. Interestingly, the adsorbent material exhibited a highly negatively charged surface which was extremely beneficial for La(III) and Ce(III), which are positively charged and therefore were easily attracted to each other. The kinetic data were well fitted by pseudo-second-order, while the Liu model agreeably fitted equilibrium data. The maximum adsorption capacities for Ce(III) and La(III) were 107.7 and 127.2 mg g-1 at 298 K, respectively. The thermodynamic data indicated that the adsorption systems between SP-AC and both REEs were favorable, spontaneous, and exothermic. The adsorption mechanisms between SP-AC and the two REEs were proposed based on the experimental results, adsorbent characteristics, and statistical physics approach. Pore filling and ion exchange were the main mechanisms, although surface complexation was also involved. Finally, the SP-AC was employed to recover many REEs from real phosphogypsum leachate, demonstrating that SP-AC can selectively recover REEs in the real process.
|
|
| 8. |
- Grimm, Alejandro, et al.
(författare)
-
Cellulose fiber rejects as raw material for integrated production of pleurotus spp. mushrooms and activated biochar for removal of emerging pollutants from aqueous media
- 2023
-
Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 8:6, s. 5361-5376
-
Tidskriftsartikel (refereegranskat)abstract
- Cellulose fiber rejects from industrial-scale recycling of waste papers were dried and de-ashed using a combined cyclone-drying and sieving process. The upgraded fiber reject was used as a component of substrates for the cultivation of Pleurotus ostreatus and Pleurotus eryngii mushrooms. Acetic acid (AA) and acid whey (AW) were used to adjust the pH of fiber reject-based substrates. Spent substrate (SMS) was used for the production of activated biochar using H3PO4 and KOH as activating agents and pyrolysis temperatures of 500, 600, and 700 °C. The effectiveness of the biochars in removing pollutants from water was determined using acetaminophen and amoxicillin. By using a feeding rate of 250 kg/h and a drying air temperature of 70 °C, the moisture content of the raw fiber rejects (57.8 wt %) was reduced to 5.4 wt %, and the ash content (39.2 wt %) was reduced to 21.5 wt %. Substrates with 60 and 80 wt % de-ashed cellulose fiber were colonized faster than a birch wood-based control substrate. The adjustment of the pH of these two substrates to approximately 6.5 by using AA led to longer colonization times but biological efficiencies (BEs) that were higher or comparable to that of the control substrate. The contents of ash, crude fiber, crude fat, and crude protein of fruit bodies grown on fiber reject-based substrates were comparable to that of those grown on control substrates, and the contents of toxic heavy metals, that is, As, Pb, Cd, and Hg, were well below the up-limit values for food products set in EC regulations. Activated biochar produced from fiber reject-based SMS at a temperature of 700 °C resulted in a surface area (BET) of 396 m2/g (H3PO4-activated biochar) and 199 m2/g (KOH-activated biochar). For both activated biochars, the kinetics of adsorption of acetaminophen and amoxicillin were better described using the general order model. The isotherms of adsorption were better described by the Freundlich model (H3PO4-activated biochar) and the Langmuir model (KOH-activated biochar).
|
|
| 9. |
- Grimm, Alejandro, et al.
(författare)
-
Hardwood spent mushroom substrate–based activated biochar as a sustainable bioresource for removal of emerging pollutants from wastewater
- 2024
-
Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 14, s. 2293-2309
-
Tidskriftsartikel (refereegranskat)abstract
- Hardwood spent mushroom substrate was employed as a carbon precursor to prepare activated biochars using phosphoric acid (H3PO4) as chemical activator. The activation process was carried out using an impregnation ratio of 1 precursor:2 H3PO4; pyrolysis temperatures of 700, 800, and 900 °C; heating rate of 10 °C min−1; and treatment time of 1 h. The specific surface area (SSA) of the biochars reached 975, 1031, and 1215 m2 g−1 for the samples pyrolyzed at 700, 800, and 900 °C, respectively. The percentage of mesopores in their structures was 75.4%, 78.5%, and 82.3% for the samples pyrolyzed at 700, 800, and 900 °C, respectively. Chemical characterization of the biochars indicated disordered carbon structures with the presence of oxygen and phosphorous functional groups on their surfaces. The biochars were successfully tested to adsorb acetaminophen and treat two simulated pharmaceutical effluents composed of organic and inorganic compounds. The kinetic data from adsorption of acetaminophen were fitted to the Avrami fractional-order model, and the equilibrium data was well represented by the Liu isotherm model, attaining a maximum adsorption capacity of 236.8 mg g−1 for the biochar produced at 900 °C. The adsorption process suggests that the pore-filling mechanism mainly dominates the acetaminophen removal, although van der Walls forces are also involved. The biochar produced at 900 °C removed up to 84.7% of the contaminants in the simulated effluents. Regeneration tests using 0.1 M NaOH + 20% EtOH as eluent showed that the biochars could be reused; however, the adsorption capacity was reduced by approximately 50% after three adsorption–desorption cycles.
|
|
| 10. |
- Grimm, Alejandro, et al.
(författare)
-
Removal of diphenols using pine biochar. Kinetics, equilibrium, thermodynamics, and mechanism of uptake
- 2022
-
Ingår i: Journal of Molecular Liquids. - : Elsevier BV. - 0167-7322 .- 1873-3166. ; 364
-
Tidskriftsartikel (refereegranskat)abstract
- Thermal pyrolysis synthesized activated biochar from the Pinus elliottii sawdust (PS) at 600° C. The obtained activated biochar (PB600) was used for the removal of three diphenols, catechol (CAT), resorcinol (RES), and hydroquinone (HYD), which are utilized mainly in different industries. The PB600 was characterized by several analytical techniques. The BET surface area of 1473 m2.g−1 and a total pore volume of 0.707 cm3 g−1 was obtained. The functional groups and amount of acidic and basic groups on the biochar were determined by FTIR and Bohem titration, respectively. From the isotherm studies, it was obtained that the maximum adsorption capacities (Qmax) based on the Liu isotherm model were 419.8 (CAT 45 °C), 263.8 (RES 40 °C), and 500.9 mg g−1 (HYD 25 °C). The values of thermodynamic parameters demonstrated that CAT, RES, and HYD adsorption processes were spontaneous, exothermic, and energetically favorable, and the magnitude of ΔH° was compatible with physisorption. The CAT, RES, and HYD adsorption mechanism onto the biochar is followed by porous filling, π-π interactions, and hydrogen bonds. Subsequently, PB600 biochar was employed as a potential adsorbent for treating simulated industrial effluents in a complex matrix simulating a real industrial effluent, and the overall removal attained up to 95.97 %. In concert with the experimental results, the electronic properties of the developed adsorption systems, including frontier molecular orbitals, charge density difference, and partial density of states, were studied by the density functional theory (DFT) approach to explore the mechanism of adsorption on the activated biochar surface.
|
|
