Activated Carbon Research Articles

Acid-treated waste sisal fiber derived activated carbon as efficient electrode material for solid-state supercapacitor

Activated Carbon (AC), obtained from biomass is highly adaptable and valued for its versatile benefits including high surface area, conductivity, chemical inertness, etc. in various applications. It is also used as an electrode in supercapacitors for applications requiring a high-power supply. Sisal fiber, derived from the Agave sisalana plant, has several advantages, including its fibrous and porous framework, that make it suitable for conversion into activated carbon for energy storage applications in the context of sustainability and reduced environmental impact. In this study, we have prepared H2SO4 treated KOH activated carbon from residual Sisal fiber (SFH2AC) which is then utilized as an electrode material for supercapacitors. SFH2AC exhibits hierarchical and structure-based porosity with a large specific surface area (SA) of 1185 m2/g and shows the maximum specific capacitance (Cs) of 340 F/g @ 0.5 A/g in 6 M KOH electrolyte. In KOH electrolyte, strong cycling retention (during the length of 9000 GCD cycles) is attained as; 98 % up to the first 3000 cycles at 10 A/g, 93 % up to next 3000 cycles at 20 A/g, and 90 % up to the last 3000 cycles at 30 A/g. Furthermore, the SFH2AC//SFH2AC(Gel) device was built by using SFH2AC as electrodes with PVA/KOH gel as an electrolyte in order to assess the supercapacitor performance in real time. The device has a specific power density of 7500 W/kg and a maximum energy density of 12 W h/kg. The device reveals an exceptional 97 % cycling stability, maintaining up to 9000 repeated GCD cycles at an increased current density (CD) of 30 A/g.

Activated Carbon and Biochar Derived from Sargassum sp. Applied in Polyurethane-Based Materials Development.

Activated carbon (AC) and biochar (BC) are porous materials with large surface areas and widely used in environmental and industrial applications. In this study, different types of AC and BC samples were produced from Sargassum sp. by a chemical activation and pyrolysis process and compared to commercial activated carbon samples. All samples were characterized using various techniques to understand their structure and functionalities. The metal content of the samples was characterized by using an inductively coupled optical emission spectrometer (ICP-OES). A toxicity test was applied to investigate the effect of AC/BC on organisms, where Sinapis alba seed and Escherichia coli bacteria-based toxicity tests were used. The results revealed that the samples did not negatively affect these two organisms. Thus, it is safe to use them in various applications. Therefore, the samples were tested as fillers in polyurethane composites and, thus, polyurethane-AC/BC samples were prepared. The amounts of AC/BC mixed into the polyurethane formulation were 1%, 2%, and 3%. Mechanical and acoustic properties of these composites were analyzed, showing that by adding the AC/BC to the system an increase in the compression strength for all the samples was achieved. A similar effect of the AC/BC was noticed in the acoustic measurements, where adding AC/BC enhanced the sound adsorption coefficient (α) for all composite materials.

Carbon Materials with Different Dimensions Supported Pt Catalysts for Selective Hydrogenation of 3,4-Dichloronitrobenzene to 3,4-Dichloroaniline

In this study, carbon materials with different dimensions, including the typical one-dimensional (1D) carbon nanotube (CNT), two-dimensional (2D) graphene (GF), and three-dimensional (3D) activated carbon (AC), were investigated as a support for Pt catalysts for the selective hydrogenation of 3,4-dichloronitrobenzene (3,4-DCNB) to 3,4-dichloroaniline (3,4-DCAN). Notably, the Pt/CNT catalyst with the lowest dimension exhibited the best conversion of 3,4-DCNB under mild reaction conditions, followed by Pt/GF. Comprehensive characterizations, including XRD, TEM, XPS, and in situ CO DRIFTS, reveal that the dimension of carbon supports plays an important role in the particle size and electronic properties of Pt species, consequently affecting the catalytic performances of Pt catalysts. According to the results, electron-deficient Pt particles with small sizes are more favorable for the hydrogenation of 3,4-DCNB to 3,4-DCAN. In addition, dynamic tests and in situ DRIFTS of 3,4-DCNB indicated that the carbonaceous supports will largely influence the adsorption and activation capacity of the Pt catalysts, so that Pt loaded on CNT and GF are superior to that on the AC. We believe this study will provide good guidance for designing efficient carbon-supported metal catalysts for selective hydrogenation.

Biosorption of Pb(II) Ions through Nanostructured Teff Straw based Magnetized Activated Biocarbon: Aspects on Modeling, Optimization, and Kinetics

<p>In this study, activated carbon (AC) was prepared from teff grass straw via chemical activation and microwave-assisted pyrolysis. The AC was modified by magnetization followed by it was characterized by particle size, FTIR, XRD, thermogravimetric study, pore size, and magnetic properties. Further, it was evaluated for its adsorptive removal performance of lead (II) ions from aqueous solution. A statistical model was developed by response surface method (RSM) and the crucial parameters, concentration of initial Pb(II), biosorbent loading, solution pH, and contact time were optimized for maximizing the adsorption of Pb(II) ions. The optimal values were 95.36 mg/L, 0.656 g/100 mL, 5.5, and 88.7 min, respectively for aforementioned parameters. Under the optimal condition, the Langmuir isotherm exhibited the most accurate correspondence with the obtained experimental data. The findings from the kinetic analysis were found to be statistically fit to the pseudo-2nd order model.</p>

The Degradation of Polyethylene by Trichoderma and Its Impact on Soil Organic Carbon

Polyethylene mulching film, which is widely utilized in arid and semi-arid agriculture, leaves residual pollution. A novel approach to addressing this issue is microbial degradation. To screen the strains that degrade polyethylene efficiently and clarify the effect of degrading strains on the turnover of soil organic carbon, a polyethylene-degrading fungus PF2, identified as Trichoderma asperellum, was isolated from long-time polyethylene-covered soil. Strain PF2 induced surface damage and ether bonds, ketone groups and other active functional groups in polyethylene, with 4.15% weight loss after 30 days, where laccase plays a key role in the degradation of polyethylene. When applied to soil, the Trichoderma-to-soil weight ratios were the following: B1: 1:100; B2: 1:200; B3: 1:300 and B4: 1:400. Trichoderma asperellum significantly increased the cumulative CO2 mineralization and soil organic carbon mineralization in the B1 and B2 treatments compared with the control (B0). The treatments B1, B3 and B4 increased the stable organic carbon content in soil. An increase in the soil organic carbon content was observed with the application of Trichoderma asperellum, ranging from 27.87% to 58.38%. A positive correlation between CO2 emissions and soil organic carbon was observed, with the soil carbon pool management index (CPMI) being most correlated with active organic carbon. Trichoderma treatments improved the CPMI, with B3 showing the most favorable carbon retention value. Thus, Trichoderma asperellum not only degrades polyethylene but also contributes to carbon sequestration and soil fertility when applied appropriately.

The role of the activation heating source on the carbon capture performance of two new adsorbents produced from household-mixed-plastic waste

This study reveals the impact of the activation with microwave and conventional heating sources on textural properties and CO2 uptake of a mixed plastic-based char. Two mixed plastic-based adsorbents, one activated using microwaves and the other using conventional heating, were produced at optimum activation conditions, and subsequently compared. The findings show that both heating sources produced microporous adsorbents, but activation heating sources influenced their physicochemical properties and CO2 uptake. The microwave-produced activated carbon (AC) displayed superior BET surface area, total, micro- and ultra-micropore volumes compared to the conventionally produced AC. The microwave-produced AC possessed CO2 adsorption capacities of 1.66 and 2.37 mmol/g under dynamic and equilibrium conditions, respectively, at 25 °C and 1 bar. These capacities represent an 8 and 30 % higher uptake, respectively, compared to the 1.53 and 1.66 mmol/g displayed by the conventionally prepared AC under the same adsorption conditions. Both samples displayed stable and excellent CO2 recyclability over 10 adsorption-desorption cycles, with desorption efficiencies ranging from 93.46 % to 96.72 % (microwave- and conventionally- produced ACs respectively). The Avrami model most accurately described the experimental CO2 adsorption data under dynamic conditions, while the Sip model gave the best fit for equilibrium conditions. These findings apply to both types of ACs at various temperatures, irrespective of the heating source. Overall microwave heating is more efficient than conventional heating, requiring 300°C lower temperature, 115 minutes shorter time, 0.79 kWh less energy, and less KOH. It improves CO2 uptake and reduces production costs by 80 %, offering a sustainable alternative for CO2 adsorbent production.

Assessing Adsorption and Desorption Performance in the Recovery of Volatile Organic Compounds

In this study, the activated carbon fiber filter design and VOC adsorption and desorption performance were evaluated based on the development of a filter regeneration device to treat VOCs in high efficiency and low cost. Activated carbon fiber (ACF) has the advantage of fast adsorption speed and high adsorption capacity because micropores are formed on the surface and a large specific surface area. However, the specific gravity is about 25 times lower than that of activated carbon (AC), so the amount of adsorbent that can fill the same volume is small. In order to solve this problem, the regeneration device is implemented by repeating adsorption and regeneration for a short time, and a cylindrical adsorption filter made of activated carbon fiber is designed according to the operating conditions of the regeneration device. At this time, the pollutant gas and regenerated air are uniformly distributed over the entire adsorbent, and the flow characteristics according to the supply of the pollutant gas and the regeneration gas are analyzed. When the size of the lower part of the cylindrical adsorption filter is smaller than the size of the upper part under the condition that the pollutant gas flows downward, a uniform distribution of the pollutant gas is possible. In addition, as the space velocity decreases, the adsorption capacity decreases, and the differential pressure increases rapidly. Through the regeneration experiment, it was confirmed that the desorption concentration of MEK was higher and the desorption concentration was higher. In addition, the regenerated air is uniformly dispersed throughout the adsorption filter, toluene, o-xylene, and methyl ethyl ketone, which are representative substances of volatile organic compounds (VOCs), are injected with 400 ppm, and then regenerated air is supplied at 150 °C to analyze adsorption characteristics and regeneration concentrations. As a result of the experiment, the adsorption capacity ratio to 1 g of regeneration air according to the type of VOCs was 0.48, 0.36, and 0.25 g in the order of o-xylene, toluene, and methyl ethyl ketone. In addition, as the space velocity decreases, the adsorption capacity decreases, and the differential pressure increases rapidly. Through the regeneration experiment, it was confirmed that the desorption concentration of MEK was higher and the desorption concentration of o-xylene was discharged at a relatively low concentration. Moreover, even if the adsorption concentration changes, there was no difference in the regeneration concentration change. Therefore, the filter was designed based on the spatial speed of the regeneration device of 51,000 -h or less, and the adsorption capacity ratio to 1 g of the regeneration air amount was 0.1 g, thereby enhancing the filter's recycling performance and VOCs emission effect.

Characteristics of organic carbon in tobacco-growing soils with different pH

This paper deal with the analysis of the relationship between acidity and alkalinity with organic carbon structure and humus components of tobacco-growing soils in Tengchong city. Under the same level of organic matter and nutrient content, soils with different pH values in Tengchong city were selected for the investigation. Results showed that the HA/FA values of the soil with low organic matter content gradually decreased with increasing pH, indicating a higher content of active carbon components and a lower content of stable carbon components in the soils. In soils with high organic matter content, pH value showed a highly significant negative correlation with HA/FA and PQ values. With increasing acidity, HA/FA became higher, and humus components with high stability increased. At the same level of organic matter content, the infrared A2920/A1630 ratio gradually increased with increasing pH. It indicates that at a certain pH range and the same level of organic matter content, the stable humus component increases, and the soil pH value decreases. Bangladesh J. Bot. 53(3): 745-755, 2024 (September) Special

The Impact of Activated Carbon–MexOy (Me = Bi, Mo, Zn) Additives on the Thermal Decomposition Kinetics of the Ammonium Nitrate–Magnesium–Nitrocellulose Composite

This research investigates the impact of additives such as activated carbon (AC) combined with metal oxides (Bi2O3, MoO3, and ZnO) on the thermal decomposition kinetics of ammonium nitrate (AN), magnesium (Mg), and nitrocellulose (NC) as a basic AN–Mg–NC composite. To study the thermal properties of the AN–Mg–NC composite with and without the AC–MexOy (Me = Bi, Mo, Zn) additive, a differential scanning calorimetry (DSC) analysis was conducted. The DSC results show that the AC–MexOy (Me = Bi, Mo, Zn) additive catalytically affects the basic AN–Mg–NC composite, lowering the peak decomposition temperature (Tmax) from 534.58 K (AN–Mg–NC) to 490.15 K (with the addition of AC), 490.76 K (with AC–Bi2O3), 492.17 K (with AC–MoO3), and 492.38 K (with AC–ZnO) at a heating rate of β equal to 5 K/min. Based on the DSC data, the activation energies (Ea) for the AN–Mg–NC, AN–Mg–NC–AC, and AN–Mg–NC–AC–MexOy (Me = Bi, Mo, Zn) composites were determined using the Kissinger method. The results suggest that incorporating AC and AC–MexOy (Me = Bi, Mo, Zn) additives reduce the decomposition temperatures and activation energies of the basic AN–Mg–NC composite. Specifically, Ea decreased from 99.02 kJ/mol (for AN–Mg–NC) to 93.63 kJ/mol (with addition of AC), 91.45 kJ/mol (with AC–Bi2O3), 91.65 kJ/mol (with AC–MoO3), and 91.76 kJ/mol (with AC–ZnO). These findings underscore the potential of using AC–MexOy (Me = Bi, Mo, Zn) as a catalytic additive to enhance the performance of AN–Mg–NC-based energetic materials, increasing their efficiency and reliability for use in solid propellants.

Comparative Remediation of Arsenic and Antimony Co-Contaminated Soil by Iron- and Manganese-Modified Activated Carbon and Biochar.

At present, soil contaminated with arsenic (As) and antimony (Sb) is escalating at an alarming rate, which is harmful to human health. In this study, Fe- and Mn-modified activated carbon (AC) and biochar (BC) were prepared and compared for the remediation of As- and Sb-contaminated soil. The effects on the speciation of As and Sb, soil pH, organic matter (SOM), and enzyme activity with various dosages and remediation times were investigated. The results showed that on the whole, the best stabilization effect of As and Sb was achieved with 3% FeMnBC. Furthermore, with increases in time and dosage, the immobilization effect on As and Sb was more significant. Fe/Mn-modified AC and BC enhanced soil pH, with 3% MnAC being particularly effective; 3% AC and 3% FeMnAC demonstrated the most pronounced enhancement in SOM. The modified carbon materials exhibited a dramatic increase in enzymatic activity. In particular, urease activity showed an increasing trend, and catalase activity first decreased and then increased over 30 days. Among the treatments, 3% MnAC showed the most significant enhancements in catalase and urease activities, whereas 1% FeMnBC had the most pronounced effect on increasing sucrase activity. This study provides theoretical support for the remediation of soil co-contaminated with As and Sb by Fe/Mn-modified AC and BC.

Low temperature physical activation of raw charcoal for excellent dye adsorption kinetics

The current work illustrates the physical activation of raw charcoal to produce activated carbon (AC) at low temperatures (300 and 500 °C). Prepared ACs are tested for Methylene blue (MB) adsorption experiments at various adsorption conditions (e.g., pH, temperature) and discussed efficiency, kinetics, isotherm models, and adsorption mechanism to determine the optimal adsorption conditions for the removal of MB dye. The results show that the prepared ACs (AC1, AC2 at 300 and 500 °C) efficiently absorb MB and obtain removal efficiency of ∼100 and 83% in 1 h, respectively. When the pseudo-first-order and pseudo-second-order adsorption kinematic models are used to test the adsorption data, the result fits the pseudo-first-order model better. The Freundlich and Langmuir adsorption isotherms are employed to model the isotherm data to get the maximum adsorption capacity (MAC). The MAC for AC1 and AC2 is found to be 39.14 and 40.98 mg/g, respectively. Additionally, MB adsorption has been analyzed using the Temkin and Dubinin–Radushkevich isotherm models, along with the inter-particle diffusion model. The Dubinin–Radushkevich model suggests that MB adsorption is a physical absorption process. The Temkin model showed that the Temkin constant (B) values are positive indicating that the adsorption is exothermic. The inter-particle diffusion model revealed that AC2 displays greater adsorption kinetics consistency due to its larger pore diameter. The results reveal that the Langmuir model captured the data better, demonstrating that monolayer adsorption dominated the absorption process. Additionally, prepared ACs are examined for reuse, and exhibit three cycles of recyclability. As a result, ACs made from oak wood charcoal are an easy affordable way to get rid of MB dye.

Rich-N highly branched COF loaded with imidazolyl ionic liquids for highly efficient catalysis of CO2 conversion under atmospheric pressure

The highly loaded ionic active centers and carbon dioxide (CO2) affinity sites play pivotal roles in catalyzing the gas-solid-liquid three-phase reaction in CO2 cycloaddition. In this study, a kind of rich-N highly branched Covalent organic framework loaded with imidazolyl ionic liquids (DhaTat-COF-IL) was synthesized through a nucleophilic substitution reaction, which bridged the highly loaded imidazolyl ionic liquids (Im-IL) active centers (20.72 %) and strong CO2-philic sites, efficiently promoting the in-situ of CO2 conversion at catalyst interface. The rich-N highly branched Covalent organic framework (DhaTat-COF) benefits from its abundant CO2-philic groups (imine and triazine groups) and microporous properties, exhibiting excellent CO2 enrichment capacity, designed as a porous crystalline material for anchoring high active Im-IL. The resultant DhaTat-COF-IL achieved a quantitative yield of 95 % (selectivity > 99 %) in converting epichlorohydrin (ECH) under ambient pressure at 80 ℃, with a turnover frequency (TOF) value reaching 1582 h⁻¹ at 120 ℃. Additionally, yields of ≥ 94 % were obtained for various terminal-substituted epoxides. Density Functional Theory (DFT) analysis reveals a synergistic effect between −CH and Br− in the DhaTat-COF-IL during catalytic cycling. This work provides valuable insights into the targeted design and performance optimization of Im-IL-grafted COF-based catalysts, emphasizing high efficiency and sustainability in CO₂ conversion.

Effect of carbonaceous materials on phosphorus removal in flow-through packed column systems.

Phosphorus (P) overloading in aquatic environments has long-been recognized as the leading cause of water quality deterioration, harmful algal bloom, and eutrophication. This study investigated P removal performance by five cost-effective carbonaceous materials (CMs) in flow-through packed column systems. These CMs include biochars pyrolyzed from feedstocks of Eucalyptus (E-biochar) and Douglas fir (D-biochar), commercial biochar (C-biochar), iron oxide-coated biochar (Fe-biochar), and commercial activated carbon (AC). The physicochemical properties of CMs, such as specific surface area (SSA), pore volume, pore diameter, elemental composition, and surface charge, were characterized. The packed column experimental results showed that P removal performance followed the order: E-biochar < D-biochar < C-biochar < Fe-biochar < AC. Specifically, the sorption capacity of 1mg/L of P in packed columns was 0.0036mg P/g E-biochar, 0.0111mg P/g D-biochar, 0.0369mg P/g D-biochar, 0.077mg P/g Fe-biochar, and 0.088mg P/g AC, respectively. The largest SSA (1012 m2/g) and pore volume (0.57 cm3/g) of AC accounted for the most outstanding P removal efficiency mainly by physical sorption, while electrostatic interaction explained the high P removal by Fe-biochar (SSA as low as 32.4 m2/g). Our findings provide direct practical implications for effectively removing P in water by cost-effective CMs.

Modification of activated carbon to enhance the absorption of PCDD/F and dl-PCBs emissions in flue gas in South Africa

Activated carbon (AC) adsorption is commonly used for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) removal from flue gas. However, the AC available in the market predominantly possesses a substantial specific surface area and numerous micropores leading to significant variations in their adsorption characteristics. In this study, three types of activated carbon (AC) impregnated with different activating agents, namely K2CO3, KOH, and H3PO4 were evaluated for their effectiveness in removing PCDD/Fs and dl-PCBs compounds. For dl-PCBs, AC impregnated with H3PO4 resulted in a substantial reduction of PCB concentrations with an impressive 98% reduction achieved. Impregnation with KOH proved even more effective attaining a remarkable 99% reduction. In contrast, impregnation with K2CO3 while still effective achieved a slightly lower reduction rate of 95%. For PCDD/F, LACH3PO4 showed selectivity in achieving high reductions across both CDD and CDF congeners however proved effective in reducing the ∑PCCDF from 403.94 ng/Nm3 to 3.463 ng/Nm3 and ∑TEQ from 41.34 ng I-TEQ/Nm3 to 0.35 ng I-TEQ Nm3. LACKOH proved effective in reducing the ∑PCCDF from 540.45 ng/Nm3 to 0.25 ng/Nm3 and ∑TEQ from 57.42 ng I-TEQ/Nm3 to 0.12 ng I-TEQ Nm3 obtaining the overall removal efficiency of 99.5%. While the LACKOH injections were successful in the absorption of PCDD/Fs from the gas phase, it was observed that certain PCDD/F congeners became desorbed and entrapped within the ash necessitating further treatment of the ash residue. The ash underwent a thermal treatment first at 300 °C and 500 °C. The thermal treatment at 500 °C achieved a remarkable degradation of 99.7% removal efficiency rendering the ash and residue safe for disposal in a landfill site.Graphical

Investigation of Far Infrared Emission and UV Protection Properties of Polypropylene Composites Embedded with Candlenut-Derived Biochar for Health Textiles.

Far infrared radiation (FIR) within the wavelength range of 4-14 μm can offer human health benefits, such as improving blood flow. Therefore, additives that emit far infrared radiation have the potential to be incorporated into polymer/fabric matrices to develop textiles that could promote health. In this study, biochar derived from candlenuts and pyrolyzed with activated carbon (AC) was incorporated into polypropylene (PP) films and investigated for its potential as a health-promoting textile additive. The properties of biochar were compared with other far infrared (FIR) emitting additives such as hematite, Indian red ochre, and graphene. The addition of biochar increased FIR emissivity to 0.90, which is 9% higher than that of pristine PP. Additionally, biochar enhanced UV and near-infrared (NIR) blocking capabilities, achieving an ultra-protection factor (UPF) of 91.41 and NIR shielding of 95.85%. Incorporating 2 wt% biochar resulted in a 3.3-fold higher temperature increase compared to pristine PP after 30 s of exposure to an FIR source, demonstrating improved heat retention. Furthermore, the ability to achieve the lowest thermal effusivity among other additives supports the potential use of biochar-incorporated fabric as a warming material in cold climates. The tensile properties of PP films with biochar were superior to those with other additives, potentially contributing to a longer product lifespan. Additionally, samples with red ochre exhibited the highest FIR emissivity, while samples with hematite showed the highest capacity for UV shielding.

New Synthetic Approaches for the Construction of Enantioenriched Molecules Bearing Quaternary Stereocenters

AbstractOptically active molecule architectures stand as an important class of organic compounds and occupy a key role in academic and industrial communities. Particularly, the molecules bearing quaternary carbon are of vital importance because of its favorable conformation and valuable three‐dimensional molecules, which frequently play a key role in a broad spectrum of functional materials, pharmaceutical relevant natural molecules, and agrochemicals. Over the past few decades, a large number of synthetic strategies for the enantioselective construction of compounds with chiral quaternary carbon centers have been the focus of a number of research initiatives. In this review, the state‐of‐the‐art toward the synthesis of enantioenriched molecules bearing quaternary stereocenters are summarized, which could be segmented into four categories: 1) Construction of optically active quaternary carbon centers by addition to prochiral sp2 carbon; 2) Construction of optically active all‐carbon quaternary stereocenters via substitution at non‐chiral tetra‐substituted carbon; 3) Construction of optically active all‐carbon quaternary stereocenters via kinetic resolution; 4) Construction of optically active all‐carbon quaternary stereocenters via desymmetrization reactions.

Competitive adsorption behavior and adsorption mechanism of limestone and activated carbon in polymetallic acid mine water treatment

Acid mine water (AMD) can cause significant environmental hazards due to its high concentration of metal ions, so the development of effective treatment methods is essential to mitigate its impact. In this study, adsorption experiments were conducted using limestone (LS) and activated carbon (AC) to explore the adsorption efficiency for different concentrations of metal ions. Adsorption was evaluated by static and competitive batch tests. The adsorbent mechanism was investigated using analytical techniques such as SEM, FTIR and XRD. The efficacy of LS and AC for competitive adsorption of Fe, Mn, Zn and Cu ions from AMD was evaluated. The study analyzed the effect of environmental conditions such as initial concentration and ionic strength on the adsorption efficiency. The results showed that LS showed high adsorption capacity for Fe and Cu, but was less effective in competitive adsorption of Mn. AC showed superior adsorption performance for Fe and Cu under competitive conditions due to its high surface area and functional groups. Both adsorbents showed selective efficacy influenced by the physicochemical properties of metal ions. This study helps to guide the optimization of adsorbents in AMD treatment and highlights the importance of selecting suitable materials based on specific metal ion properties.

Effects of electrode/electrolyte materials on heavy-metal removal in industrial wastewater with flow capacitive deionization method

The expansion of industrial facilities poses a significant environmental risk due to the generation of extensive wastewater containing complex components that effluent human health. Flow-electrode Capacitive Deionization (FCDI) technology has emerged as a promising solution for wastewater treatment due to its unlimited adsorption capacity and continuous long-term operations compared to conventional systems. This study investigates the efficiency of the FCDI system in purifying industrial wastewater by extracting complex heavy metal ions, intending to achieve complete recycling and zero discharge. Different electrolyte/electrode materials were investigated to achieve high removal efficiency, including electrolytes such as sodium chloride (NaCl) and sodium sulfate (Na2SO4), and electrodes such as active carbon (AC) and C65 carbon black (C65 CB) used in lithium-ion batteries. We found that the innovative combination of Na2SO4 electrolyte with 0.1 g of C65 CB exhibited an exceptional salt removal efficiency of 90 %, surpassing NaCl electrolyte which showed 68 % efficiency. Additionally, we observed higher adsorption with C65 CB slurry compared to AC when using Na2SO4 electrolyte. To deepen our insights, Molecular Dynamics (MD) simulations were conducted to explore heavy metal ions interactions with electrode/electrolyte and membrane materials under an electric field. The results indicated that Ni2+ ions had the highest passage rate of 80 % across the membrane, followed by Cr2+, Cu2+, and Zn2+. Furthermore, superior adsorption of Ni2+ ions onto the C65 CB electrode was noted, contributing to enhanced charge transfer and overall conductivity. Furthermore, we evaluated the economic and environmental implications associated with implementing the FCDI system in practical. This study presents a novel approach by using C65 carbon black (CB) with Na2SO4 as the electrolyte, indicating high adsorption efficiency at low carbon loading electrode. This combination offers a cost-effective and sustainable solution for improving complex heavy metal ion removal in FCDI systems. Overall, our study’s findings significantly contribute to offering crucial insights into optimizing FCDI technology for efficient heavy metal ions removal in industrial wastewater treatment using lithium-ion battery anode/cathode electrode material.

The versatility of iota-carrageenan biopolymer for the fabrication of non-toxic bio-based energy storage devices

The number of portable devices produced worldwide is strongly increasing, which results in an increasing need for energy storage devices. These devices are typically fabricated with scarce and toxic materials. Consequently, there is a current trend towards the substitution of these materials by biopolymers, although they are still often mixed with toxic substances to improve specific performance aspects. To address this issue, this work presents a self-standing non-toxic and potentially biodegradable polymer electrolyte membrane for electrochemical energy storage applications consisting of an abundant biopolymer, iota-carrageenan, and Deep Eutectic Solvent (DES).11List of abbreviations: DES: Deep eutectic solvent [EMIM][SCN]: 1-Ethyl-3-methyl-imidazolium thiocyanate CV: Cyclic voltammetry FTIR: Fourier transformed infrared spectroscopy EIS: Electrochemical impedance spectroscopy CPE: Constant phase element. Ionic conductivities as high as 2 mS/cm were achieved for a proportion of carrageenan and DES of 25:75. Aqueous electrically conductive inks containing carbon black and active carbon were also developed using the same polymeric matrix. The inks were successfully printed (stencil method) on different substrates and electrically characterized, achieving sheet resistances as low as 38 Ω/sq. Supercapacitors were then fabricated by printing the electrically conductive ink on both sides of the self-standing membrane, demonstrating the versatility of iota-carrageenan biopolymer in the development of sustainable energy storage devices. The measured capacitance of the supercapacitors was 3.3 mF/cm2 in cyclic voltammetry characterization and 2.7 mF/cm2 when charging-discharging at 0.05 mA/cm2. The supercapacitors were found to be stable in cyclability studies, showing a capacity retention of 99 % after 5000 charge–discharge cycles.

Molecular Simulation of Cyclohexane in Nanoporous Materials: Adsorption of Conformers and Coadsorption with Water and Carbon Dioxide.

Molecular simulation is used to investigate the adsorption of an organic molecule and its different conformers into various nanoporous adsorbents. In more detail, we perform grand canonical Monte Carlo simulations to determine the adsorption isotherms for cyclohexane with its three conformers (chair, boat, and twisted boat) at three different temperatures into a molecular model of active carbons and two metal-organic frameworks (MOFs) (Cu-BTC and Al-Fum). By considering the adsorption of each conformer separately, we show that the adsorption isotherms are weakly dependent on the molecular conformation. When considering the concomitant adsorption of the three conformers under realistic conditions (to verify the population of each conformer in bulk mixtures), we show that the chair conformer is predominantly adsorbed in each material. However, such favorable adsorption mostly reflects the fact that this conformer has the largest population in the bulk mixture under the same thermodynamic conditions. On the contrary, with an increase in the cyclohexane gas pressure, the adsorption of boat and twisted boat conformers increases, while that of the chair conformer decreases as packing (entropy) effects become predominant during confinement. The adsorption of cyclohexane in the active carbon and MOF materials is also considered in the presence of water and CO2 atmospheres. In the case of the Al-fumarate material, the material is found to be strongly organophilic so that water and CO2 adsorption are negligible, and cyclohexane adsorption is not affected by competitive adsorption under any considered thermodynamic condition. On the contrary, for the active carbon and Cu-BTC material, competitive adsorption between cyclohexane and water or CO2 is observed even if cyclohexane adsorption remains preferred. While the different molecules coexist in the adsorbed phase at low pressures, increasing the cyclohexane pressure beyond 103 Pa promotes cyclohexane adsorption concomitantly with water and/or CO2 desorption.