Activated Carbon Research Articles

Metal bioaccumulation and effects of olivine sand exposure on benthic marine invertebrates

Due to the anthropogenic increase of atmospheric CO2 emissions, humanity is facing the negative effects of rapid global climate change. Both active emission reduction and carbon dioxide removal (CDR) technologies are needed to meet the Paris Agreement and limit global warming to 1.5 °C by 2050. One promising CDR approach is coastal enhanced weathering (CEW), which involves the placement of sand composed of (ultra)mafic minerals like olivine in coastal zones. Although the large-scale placement of olivine sand could beneficially impact the planet through the consumption of atmospheric CO2 and reduction in ocean acidification, it may also have physical and geochemical impacts on benthic communities. The dissolution of olivine can release dissolved constituents such as trace metals that may affect marine organisms. Here we tested acute and chronic responses of marine invertebrates to olivine sand exposure, as well as examined metal accumulation in invertebrate tissue resulting from olivine dissolution. Two different ecotoxicological experiments were performed on a range of benthic marine invertebrates (amphipod, polychaete, bivalve). The first experiment included acute and chronic survival and growth tests (10 and 20 days, respectively) of olivine exposure while the second had longer (28 day) exposures to measure chronic survival and bioaccumulation of trace metals (e.g. Ni, Cr, Co) released during olivine sand dissolution. Across all fauna we observed no negative effects on acute survival or chronic growth resulting solely from olivine exposure. However, over 28 days of exposure, the bent-nosed clam Macoma nasuta experienced reduced burrowing and accumulated 4.2 ± 0.7 μg g ww−1 of Ni while the polychaete Alitta virens accumulated 3.5 ± 0.9 μg g ww−1 of Ni. No significant accumulation of any other metals was observed. Future work should include longer-term laboratory studies as well as CEW field studies to validate these findings under real-world scenarios.

Low-carbon economic scheduling of multi-energy system based on price interactive response

—Regarding the increase of carbon dioxide emissions with growing energy demand, recent emerging technologies for multi-energy system have attracted much attention, as they can effectively couple and coordinate different energies to further control carbon dioxide emissions. This paper focuses on distribution-level multi-energy system and proposes an optimal scheduling method for hydrogen support based on dual-agent energy-carbon price interactive response. Firstly, a hydrogen-supported multi-energy closed-loop flow mode is developed, which provides an effective way to improve renewable energy consumption and brings additional economic revenue of solid carbon. Secondly, a dual-agent energy-carbon price interactive response scheme is designed based on the concept of energy-carbon participation ratio, which takes carbon dioxide emissions of gas load and various carbon revenues into account. This scheme can motivate users for energy demand adjustment and active carbon dioxide reduction by setting energy and carbon prices as two guiding signals. Finally, a bi-level optimal scheduling model is proposed for dual agents of energy service provider and users to maximize the benefit of each side. Case study illustrates that the proposed model can effectively balance benefits of dual agents and has economic advantage of carbon dioxide reduction, while promoting the consumption of high proportion renewable energy and system stability.

Molten-salt-induced interpenetrated meso/macro porous structural hard carbon derived from chitosan for enhanced potassium ions storage

Hard carbon materials are commonly used as anode materials for environmentally friendly potassium-ion energy devices due to excellent development prospects. However, the poor conductivity and unsatisfactory rate performance of hard carbon limit their development. Herein, chitosan was chosen as the carbon precursor to prepare interpenetrated meso/macro-porous structural hard carbon (PC) formed by the template agent NaCl in the molten state at high temperature as the anode for potassium-ion batteries. PC with a high content of pyridinic N, pyrrolic N, and CO bonds can provide a high reversible capacity of 280.1 mAh g−1 at the current density of 0.05 A g−1, and show an improved rate performance of 173.8 mAh g−1 at 1.0 A g−1. Galvanostatic charge/discharge (GCD) curves do not exhibit an obvious plateau, indicating that surface adsorption is dominant in the potassium ions storage mechanism. The high K+ diffusion coefficient indicates that the interconnected meso/macro structure allows potassium ions to diffuse faster in PC. Therefore, using activated carbon (AC) as the cathode and PC as the anode, a potassium-ion hybrid capacitor (PIHC) is fabricated, which can achieve an energy density of 130 Wh kg−1 at the current density of 0.05 A g−1 and an energy density of 62 Wh kg−1 at 1.0 A g−1.

Enhanced asymmetric supercapacitor performance via facile construction of Cu-MOF@Co(OH)2 heterostructure

Integrating metal-organic frameworks (MOFs) with transition hydroxides has the potential to enhance the inadequate electronic conductivity and address the slow diffusion of MOF materials in electrochemical applications. Herein, we synthesized a 2D Cu-MOF and successfully prepared a Cu-MOF@Co(OH)2 heterostructure using a one-step hydrothermal method on a Co(OH)2/NF (nickel foam) substrate. The hybrid Cu-MOF@Co(OH)2 material exhibits high electrochemical reactivity, resulting in enhanced pseudocapacitor performance, with a specific capacitance of 2039.8 mF cm−2 at a current density of 1.0 mA cm−2. In addition, an asymmetric two-electrode cell was constructed using Cu-MOF@Co(OH)2/NF and activated carbon (AC)/NF, exhibiting a specific capacitance of 444.5 mF cm−2 at a current density of 1.0 mA cm−2, and demonstrating decent cycling durability with 90.1 % retention after 2000 cycles.

Activated carbon amendment of sand in the base of a permeable pavement reduces total nitrogen and nitrate leaching

Urban runoff from impermeable surfaces contains various pollutants. Stormwater samples were collected for one year from car parks on the campus of Newcastle University, located in northeast England, to monitor seasonal variation in stormwater properties and leachate quality following stormwater percolation through pilot-scale, outdoor permeable pavements. The pilot study compared an innovative ‘pollution munching’ permeable pavement with 2 % activated carbon (AC) amendment in the sand base with a conventional, un-amended sand base permeable pavement. Faecal coliforms were detected in stormwater at an average value of 3.75 ± 0.79 log10 CFUs per 100 mL. The permeable pavements without and with AC had mean log removal values of 0.81 ± 0.35 and 0.70 ± 0.35 for these faecal bacteria. The absence of genetic markers for human host associated Bacteroides (HF183) in eleven out of twelve stormwater samples showed that the faecal bacteria were mainly from animal sources. 16S rRNA gene sequencing results confirmed the presence of nitrifying bacteria from the genera Nitrosomonas, Nitrobacter, Nitrosococcus, Nitrospira, and Nitrosospira in stormwater. Nitrification and nitrate leaching was more notable for the conventional permeable pavement and may pose a groundwater pollution risk. Two percent AC amendment of the sand base reduced nitrate and total nitrogen leaching significantly compared with the conventional permeable pavement, by 57 ± 15 % and 40 ± 20 %, respectively. The AC amendment also resulted in significantly reduced Cu and DOC leaching, and lesser accumulation of PAHs by passive samplers embedded in the permeable pavement base. Hydraulic tests showed that the AC amended base layer still met the design specifications for permeable pavements, making it a promising proposition for pollution reduction in Sustainable Drainage Systems (SuDS).

In-situ targeted removal of naphthalene from groundwater by peroxymonosulfate activation using molecularly imprinted activated carbon: Efficacy, mechanism and applicability

Efficient removal of low-concentration refractory polycyclic aromatic hydrocarbons (PAHs) pollutants is crucial for ensuring groundwater safety. In this study, surface molecularly imprinted catalyst (MIP@AC) was developed based on activated carbon (AC) and molecular imprinting technology, and then MIP@AC was introduced into the simulated permeable reaction barrier to evaluate the performance of MIP@AC activated peroxymonosulfate (PMS) in in-situ targeted remediation of naphthalene (NAP) contaminated groundwater. The results showed that the relative adsorption selectivity coefficient and relative degradation selectivity coefficient of the MIP@AC material relative to the non-imprinted material AC was as high as 31.47 and 10.88, respectively; that is, MIP@AC can better resist the interference of competitive pollutants and achieve efficient targeted removal of NAP. Additionally, the reactive oxygen species (ROS) yield was higher in the MIP@AC/PMS system compared to the AC/PMS system. The target pollutant NAP was precisely enriched in the imprinted cavity of the MIP@AC, realizing that ROS production and pollutant degradation occurred simultaneously in the MIP@AC imprinted cavity. Therefore, the spatial confinement effect of the imprinted cavity shortened the mass transfer distance between the ROS and NAP, thereby reducing the loss of ROS due to self-quenching. Besides, Cl- significantly promoted the targeted removal of NAP, while HCO3- had a slight inhibitory effect; humic acid had no effect because of its larger molecular structure, which does not fit into the small imprinted cavities preferred by NAP. Importantly, the MIP@AC/PMS system demonstrated effective anti-complex matrix interference ability and targeted removal performance for NAP under natural groundwater conditions. This study can promote further research on the surface molecularly imprinted catalyst/PMS system as a new strategy for in-situ targeted remediation technology of contaminated groundwater.

Enhanced SO2, NO, and Cr (VI) removal by lignin-derived high N-doped activated carbon through one-pot strategy: Structure development, structure–performance relationship and mechanism insight

The production of high-performance activated carbon (AC) is recognized as an essential strategy for the effective utilization of lignin resources. In this work, the N-doped AC was successfully prepared by blending sodium lignosulfonate (SL) and different ratios of FeCl3 through one-pot strategy. The AC structure evolution and performance were obtained by a series of characterization and tests. The results showed that, during the activation process, FeCl3 first complexed with urea and catalyzed the depolymerization of SL, and the rapid pore development was mainly caused by the template, including formed FeCl2, Na2Fe3Cl8 and Na6FeCl8. The ratio of FeCl3/SL adjusts the AC physicochemical texture. AC-3 processed a super total specific surface area and pore volume, respectively up to 2048 m2/g and 1.47 cm3/g. Meanwhile, AC-2 showed a higher nitrogen content of 11.4 %. The as-prepared AC shows super desulfurization, denitrification and Cr (Ⅵ) removal ability. AC-2 displayed maximum sulfur capacity and NO conversion, up to 199.1 mg/g and 42.4 %. This enhanced performance is primarily attributed to the pore structure induced by FeCl3 activation, which provides a foundation for adsorption and catalytic processes, further augmented by the increased active sites due to nitrogen doping. AC-3 achieved an extremely high Cr (VI) adsorption capacity, up to 386.2 mg/g, which was primarily attributed to the redox effect of N-containing and O-containing groups on Cr (VI), in addition, the effect of physical adsorption including pore structure is not neglectable. This study highlights the significant potential of environmentally friendly lignin-based porous carbon materials for removing contaminants in both gas and liquid phases.

Photocatalytic degradation of Acid Red 18 by synthesized AgCoFe2O4@Ch/AC: Recyclable, environmentally friendly, chemically stable, and cost-effective magnetic nano hybrid catalyst

Chitosan (Ch) is a linear biodegradable natural carbohydrate polymer and the most appealing biopolymer, such as low-cost biodegradability, biocompatibility, hydrophilicity, and non-toxicity. In this case, Ch was utilized to synthesize AgCoFe2O4@Ch/Activated Carbon (AC) by the modified microwave-assisted co-precipitation method. The physical and chemical structure of magnetic nanocomposites was analyzed and characterized by Field Emission Scanning Electron Microscope (FESEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Energy Dispersive Spectroscopy (EDS), Diffuse Reflection Spectroscopy (DRS), Value stream mapping (VSM), Fourier transform spectroscopy (FTIR) and BET. The effects of various parameters on the removal of dye (Acid Red18), including catalyst dose, dye concentration, pH, and time were studied. Results showed that the highest removal efficiencies were 96.68 % and 84 % for the synthetic sample and actual wastewater, respectively, in optimal conditions (pH: 3, the initial dye concentration: 10 mgL−1, the catalyst dose: 0.14 gL−1, time: 50 min). Mineralization, according to the COD analysis, was 89.56 %. Photocatalytic degradation kinetics of Acid Red 18 followed pseudo-first order and Langmuir-Hinshelwood with constants of kc = 0.12 mg L−1 min−1 and KL-H = 0.115 Lmg−1. Synthesized photocatalytic AgCoFe2O4@Ch/AC showed high stability and after five recycling cycles was able to remove the pollutant with an efficiency of 85.6 %. So, the synthesized heterogenous magnetic nanocatalyst AgCoFe2O4@Ch/AC was easily recycled from aqueous solutions and it can be used in the removal of dyes from industries with high efficiency.

Activated Carbon Application Simultaneously Alleviates Paddy Soil Arsenic Mobilization and Carbon Emission by Decreasing Porewater Dissolved Organic Matter.

Flooding of paddy fields during the rice growing season enhances arsenic (As) mobilization and greenhouse gas (e.g., methane) emissions. In this study, an adsorbent for dissolved organic matter (DOM), namely, activated carbon (AC), was applied to an arsenic-contaminated paddy soil. The capacity for simultaneously alleviating soil carbon emissions and As accumulation in rice grains was explored. Soil microcosm incubations and 2-year pot experimental results indicated that AC amendment significantly decreased porewater DOM, Fe(III) reduction/Fe2+ release, and As release. More importantly, soil carbon dioxide and methane emissions were mitigated in anoxic microcosm incubations. Porewater DOM of pot experiments mainly consisted of humic-like fluorophores with a molecular structure of lignins and tannins, which could mediate microbial reduction of Fe(III) (oxyhydr)oxides. Soil microcosm incubation experiments cospiking with a carbon source and AC further consolidated that DOM electron shuttling and microbial carbon source functions were crucial for soil Fe(III) reduction, thus driving paddy soil As release and carbon emission. Additionally, the application of AC alleviated rice grain dimethylarsenate accumulation over 2 years. Our results highlight the importance of microbial extracellular electron transfer in driving paddy soil anaerobic respiration and decreasing porewater DOM in simultaneously remediating As contamination and mitigating methane emission in paddy fields.

Effective removal of organic and inorganic pollutants from abattoir wastewater using magnesium oxide/activated carbon nanocomposites

This study investigated the development and characterization of activated carbon (AC), magnesium oxide (MgO), and a combination of AC and MgO nanocomposite for abattoir wastewater treatment. Activated carbon was derived from Hura crepitans pods, whereas MgO nanoparticles were produced through biosynthesis. Different composite (AC/MgO) ratios (1:1, 1:2, and 2:1) were prepared using a wet impregnation technique. The efficiency of these nanoadsorbents in eliminating heavy metal pollutants were tested through batch adsorption experiments under the influence of the dosage, temperature, and contact time. Various analytical tools were used to characterize the prepared nanoadsorbents. XRD confirmed the formation of a pure MgO periclase phase, indicating a reduction in particle size with the increase in pH. The HRSEM images of the nanocomposites showed porous carbon structures with regular mesopores and spherical MgO nanoparticles. The uniform granules with agglomerated spherical shapes were confirmed by the SAED patterns, suggesting the core/shell structure of MgO from the HRTEM images. Further imaging confirmed the dispersion of carbon and magnesium in the nanocomposites, without the formation of distinct dopant oxides. The specific surface areas were determined as 2.74 m2/g for activated carbon, 27.57 m2/g for MgO, and 40.82 m2/g for activated carbon/MgO, indicating enhanced surface area due to the addition of activated carbon. Batch adsorption studies indicated that the AC/MgO nanocomposite in the 1:2 ratio exhibited the highest pollutant adsorption rate under similar conditions. The adsorption study was calculated by the pseudo-second-order and Langmuir isotherm models. The AC/MgO nanocomposite demonstrated reusability over six cycles, with a slight reduction in removal efficiency from the first cycle (98.05 % for Fe, 96.50 % for Cd, and 94.32 % for Pb) to the sixth cycle (91.10 % for Fe, 86.56 % for Cd, and 84.03 % for Pb). Overall, these findings suggest that AC/MgO nanocomposites can effectively eliminate pollutants from abattoir wastewater.

Enhancing methyl orange discoloration with TiO2/Fe2O3/AC composites: synergistic adsorption-photocatalysis

Fe2O3/TiO2/AC nanocomposites were successfully synthesized via a sol–gel method, and their efficacy in decomposing methyl orange via adsorption-photocatalytic processes was reported for the first time in this study. Systematic exploration of the physicochemical properties impacting photocatalytic activity was conducted through x-ray diffraction, scanning electron microscopy—energy-dispersive x-ray spectroscopy, and Fourier transform infrared spectroscopy (FTIR) characterizations. The study revealed that the discoloration of methyl orange resulted from a synergistic interplay between adsorption and photocatalysis. The incorporation of Fe2O3 nanoparticles significantly elevated photocatalytic activity by 70%, with additional enhancement observed upon the introduction of activated carbon (AC) particles. The synergistic effects of AC adsorption and TiO2/Fe2O3 photocatalysis exhibited remarkable efficiency in degrading methyl orange under visible light irradiation. The trial functioning of Fe2O3 and AC in the TiO2/Fe2O3/AC composite, which serves as an adsorbent, an electron trap, and a co-catalyst providing active sites, significantly improved photocatalytic activity. These findings not only contribute to understanding the crucial role of composite TiO2 in conjunction with metal and carbon-based co-catalysts but also hold valuable implications for advancing research in the development of adsorption-photocatalytic systems for wastewater treatment.

Coprecipitation routed MWCNT/CdMn2O4 nanocomposite for high performance aqueous hybrid supercapacitor

A facile coprecipitation approach is used to synthesize CdMn2O4 and a multi-walled carbon nanotube/CdMn2O4 composite. The prepared CdMn2O4 nanoparticles and multi-walled carbon nanotube/CdMn2O4 composite are characterized by numerous characterization techniques and discussed. The TEM characterization reveals that CdMn2O4 nanoparticles are attached with the multi-walled carbon nanotubes (MWCNTs). Further, the supercapacitive performance of CdMn2O4 and MWCNT/CdMn2O4 is investigated. High specific capacities (Qs) of 124.25 and 202 mAh g-1 are obtained at 1 A g-1 from CdMn2O4 nanoparticles and MWCNT/CdMn2O4 composite, correspondingly. The performance of cyclability of MWCNT/CdMn2O4 indicates the long durability of the material for commercial application. Further, an aqueous hybrid supercapacitor (HSC) is assembled by MWCNT/CdMn2O4 and activated carbon (AC). MWCNT/CdMn2O4//AC delivers an energy density of 36.80 W h kg-1 at the power density of 775 W kg-1 with the current density of 1 A g-1. Further, two yellow, two blue, two green, two red and two white color light emitted diodes (LEDs) are easily and separately lighted by two MWCNT/CdMn2O4//AC connected in series. As well, a kitchen timer and toy motor fan were powered by two MWCNT/CdMn2O4//AC connected in series.

Synergetic effect of trimetallic double hydroxide nanospikes embraced N-doped graphene nanosheets as electrode material for supercapacitors

In the energy storage sector, layered double hydroxides (LDHs) are coming to the forefront as a promising option for electrode materials. However, LDHs suffer from insufficient intrinsic conductivity and agglomeration during formation which restrict their wide applications. In this context, a two-step hydrothermal technique is employed to synthesize NiCoMn hydroxide (NCM)/N-doped graphene (NG). Initially, NG is produced through hydrothermal treatment utilizing urea to serve as both a reduction and doping source. Subsequently, a straightforward hydrothermal technique is utilized to cultivate NCM onto the surface of NG nanosheets. The electrochemical properties of NCM-NG composite with different compositions of NG have been analyzed, resulting in capacitance increment on account of increased conductivity and large number of active sites upon incorporation of NG as compared to pristine NCM. Moreover, NG nanosheets inhibit the agglomeration of NCM nanospikes. Amongst different compositions, NCM-NG-2 nanohybrid secured the highest specific capacitance (Cs) of 783.5 F/g at 0.25 A/g. The Asymmetric supercapacitor device assembled with NCM-NG-2 (anode) and activated carbon (AC) (cathode) exhibits the Cs of 114.5 F/g at 0.5 A/g. The optimized specific energy (Es) of 31.8 Wh/kg and specific power (Ps) of 473.4 W/kg with remarkable retention of 101.9 % up to 15,000 continuous cycles, indicating a higher potential of the NCM-NG-2 electrode in energy storage applications. These findings open new avenues for developing highly productive multi-material electrodes for utilization in energy storage systems.

Growing-fruits-type nanoarchitectonics of nickel‑vanadium layered double hydroxide on branches of nitrogen-rich carbon nanotube for high performance supercapacitors

An innovative structural design leverages the distinctive properties inherent in each material of three type electrode material for supercapacitors. First, polyaniline nanotubes (PN) are prepared controllably. Subsequently, the PN are carbonized into nitrogen-rich carbon nanotubes (NCN) to exploit their high electrical conductivity. Finally, a nickel‑vanadium layered double hydroxide (NiV-LDH) is grown on the surface of NCN “branches” to fabricate a nitrogen-rich carbon nanotubes/nickel‑vanadium layered double hydroxide composite material (NCN/NiV-LDH). The NCN/NiV-LDH exhibits an impressive specific capacitance of 1018.2 F g−1 at a current density of 2 A g−1, and demonstrates favorable rate capability as the capacitance value remains at 702.2 F g−1 even when the current density is tripled. Moreover, the assembled asymmetric supercapacitor comprising NCN/NiV-LDH and active carbon (AC) as the positive and negative electrodes, respectively, achieves a high energy density of 108.25 Wh kg−1, even under a power density of 7500 W kg−1.

Two step synthesis and application of porous carbon for removal of copper (II) from wastewater: Statistical optimization and equilibrium isotherm analysis

In this study, activated carbon (ACs) adsorbent was synthesized using the lignocellulosic waste (LCB) seed from Adansonia digitata L. (BSP) using two steps of hydrothermal carbonization (HTC) followed by activation. The hydrothermally produced char of BSP was activated to produce porous activated carbon BSPAC, where K2CO3 was used as a chemical activating agent. Box Behnken Design was used to optimize the input variables of pyrolysis temperature (A1), residence time (B1), and ratio (C1) for the pyrolysis process. Removal percentage (β1), percentage carbon yield (β2), and fixed carbon (β3) percentage were chosen as output responses. The analysis of variance was utilized to generate appropriate mathematical models with subsequent statistical analysis. Physiochemical characterizations were carried out for the hydrothermally carbonized sample (BSPC) and the optimized activated sample (BSPAC). Langmuir, Freundlich, and Temkin models were employed to estimate the isotherm model parameters. The results demonstrated that HTC with subsequent mild activation using K2CO3 can be considered as a greener route to obtain better-quality porous carbon having surface area of 599 m2/gm for removal of Cu(II) cations from wastewater.

Effect of Media and Calcium on the Micropropagation of Rudrakhsa (Eleocarpus ganitrus Roxb.)

The Rudraksha tree, scientifically known as Eleocarpus ganitrus Roxb., holds significant religious and medicinal value in India, making it a threatened species. This study was conducted to assess the support of the five different media on the in vitro micropropagation of E. ganitrus using nodal segments as explants. The media; Murashige and Skoog (MS), Lloyd and McCown (WPM) Anderson (AM), Gupta and Durzan (DCR) and Gamborg (B5) were supplemented with antioxidants (citric acid 10mg/l, ascorbic acid 50mg/l, activated carbon (AC) 500mg/l and polyvinyl pyrrolidine (PVP) 100mg/l), BAP (0.0,0.1, 0.3, 0.5, 1.0, 5.0 mg/l) NAA (0, 1,0, 2 mg/l) to promote plant growth. The optimal proliferation of shoots was attained by combining BAP (0.5 mg/l) and NAA (0.1 mg/l) in the MS medium, with or without CaCl2·2H2O (ranging from 1.25 to 10.0 mM/l). The calcium content was assessed accordingly. Elevated concentrations of CaCl2·2H2O in the medium mitigated hyper-hydration, with necrosis of the shoot tip notably reduced at 6.5 mM/l CaCl2·2H2O. Healthy shoots were transferred to MS medium supplemented with NAA (1.0 mg/l) to induce root initiation and multiplication. The addition of CaCl2·2H2O (5.0 mM/l) resulted in the highest recorded root multiplication. Plants that underwent successful acclimatization (80%) exhibited regular growth patterns under favorable environmental conditions.

Ultrafast dyeing wastewater purification by high-performance and reusable lignin-derived activated porous carbon filter

Achieving ultrafast purification during filtration while maintaining high adsorption capacity and low-cost filter production is a critical challenge that must be addressed immediately to promote large-scale water filter applications, particularly in remote areas without wastewater purification plants. Herein, low-cost, renewable lignin was used as a carbon source precursor to produce a high-performance, reusable activated porous carbon filter for ultrafast dye wastewater purification. Lignin-derived active porous carbon (LAPC) can achieve a high specific surface area (2276 m2/g) by using a lower amount of KOH (a mass ratio of 0.4 KOH to precursor) during the activation process, which not only meets the requirements of water transport and dye adsorption, but also reduces manufacturing costs. Owing to the pore-filling effect and electrostatic interaction, the LAPC particles displayed a high removal capacity of 1800 mg/g in the static adsorption, higher than most of the reported porous carbon. Furthermore, LAPC filters assembled from a flow of LAPC particles achieve significant dye removal (99.82 % in 30 s) during the dynamic adsorption process. Both anionic and cationic dyes can be removed and clean water can be produced simultaneously by simple dynamic filtration. Moreover, the LAPC filter could be reused for wastewater purification with a high removal efficiency (more than 95 % after 7 cycles of regeneration and use). This continuous operation, strong absorption versatility, and high efficiency of LAPC filter device for complex hybrid dyes system make it have a bright prospect in industrial dyeing wastewater treatment fields.

Preparation of a hierarchical porous activated carbon derived from cantaloupe peel/fly ash/PEDOT:PSS composites as Pt-free counter electrodes of dye-sensitized solar cells

Hierarchical porous activated carbon/fly ash/PEDOT:PSS composites (AC:FA) for a counter electrode (CE) were created using a doctor blade technique and applied in dye sensitized solar cells. Hierarchical porous activated carbon (AC) was produced using a potassium hydroxide (KOH) activation process from cantaloupe peels (Cucumis melo L. var. cantaloupensis). AC was introduced into fly ash at various mass ratios to enhance several physical and electrochemical characteristics. Compared to bare FA, the AC:FA electrode displayed a high electrocatalytic activity for the iodide/triiodide redox (I−/I3−) reaction. The test findings show that a higher proportion of AC has an impact on a CE's catalytic activity and charge transfer resistance. The power conversion efficiency (PCE) of the dye-sensitized solar cell (DSSC) attained 5.81 % using the AC:FA CE with AC in a mass ratio of FA in 3:1 (wt./wt.), which is very near the performance of manufactured DSSC's with a platinum (Pt)-based CE (5.91 %). The AC:FA CE stands out as a strong candidate to substitute for costly Pt CEs due to its enhanced electrochemical activity and charge transfer capabilities obtained with an inexpensive and simple production procedure.

Facile preparation of polyvinyl chloride/activated carbon thin-film composites and study of their microwave absorption at Ka-band frequencies

Poly(vinyl chloride) (PVC) and activated carbon (AC) powders were hot-pressed into (PVC)100– x /(AC) x thin-film composites (TFCs), where x = 0.2–30 wt%. The nanostructure, morphology, and composition of AC were investigated by TEM, SEM, and EDX. The thermal stability and surface carbon-oxygen groups of the AC filler were determined by thermolysis in air and vacuum. The AC effect on the (PVC)100– x /(AC) x TFCs transparency to the electromagnetic radiation (EMR) was demonstrated at Ka-band microwave frequencies. Characteristically, the EMR reflection of the TFCs increases with the x value. For reduced EMR reflection, these TFCs should contain only 0.2 wt% AC.

Harnessing fluorescence resonance energy transfer for improved solar still performance with zinc oxide nanoparticles and activated carbon

The Single Slope Corrugated Wick type Solar Distillers (SWS) have attracted significant research funding owing to their simple preparation process and excellent durability against heat and moisture. However, there is a recognized need to enhance their solar energy conversion efficiency. The utilization of ZnO nanoparticles (Z) in SWS is limited by their light absorption capacity, resulting in suboptimal thermal energy conversion and solar energy absorption. In this investigation, we propose an innovative method known as Fluorescence Resonance Energy Transfer (FRET), combining crystallized Z with activated carbon (AC) derived from areca nut shells. This novel approach substantially boosts the thermal efficiency of solar energy utilization in SWS by facilitating efficient energy transfer from ZAC to water.The FRET technique enables the effective transfer of energy from ZAC to water and is comprehensively analyzed. By utilizing Z as donors and AC as acceptors, the photoluminescence emitted by ZAC can be absorbed by both components, thereby increasing the carrier population as of Corrugated Wick-type towards the condenser face within SWS. The evaporation rate from water to the condensing surface is significantly higher in SWS with ZAC compared to conventional wick-type solar stills (CWS), attributed to the efficient heat transfer facilitated through multi-dimensional heterojunctions within ZAC. The energy and charge transfer processes are optimized for both summer and winter operating conditions. The ZAC-based SWS exhibits exceptional resilience in various ambient conditions, resulting in a substantial 33.989 % enhancement in distillation efficiency during summer and a notable 31.199 % improvement in winter. The incorporation of ZAC elevates the production of distillate water to 6.325 liters/m2 per day in summer and 5.840 liters/m2 per day in winter (24 h). The energy distribution among particle components is extensively scrutinized using the FRET mechanism.