Activated Carbon Particles Research Articles

Mechanical properties of the Jute fibers-activated carbon filled reinforced polyester composites

Effects of adding activated carbon particles (AC) on the mechanical properties of the bulk polyester and jute fibers/polyester composites were investigated. Four loading ratios of AC particles (1, 3, 5, and 10 wt%) were used to fill the polyester matrix. Jute fibers were treated in NaOH solution to improve their adhesion with the polyester matrix. Tensile, flexural and impact tests were conducted to specimens prepared from bulk polyester, AC-filled polyester, and jute fibers/polyester with and without AC filler. The results showed that tensile strength, flexural strength, and strain-to-failure of the polyester and jute/polyester specimens decreased as the AC particles loading was increased. However, tensile and flexural moduli increased with increasing the AC filler loading up to 3 wt% and then started to decrease after reaching their maximum values. The impact strength of the bulk polyester decreased as the AC loading was increased. However, incorporation of 3 wt% of AC into the jute/polyester composite increased its impact strength from ∼4.3 to ∼6.4 kJ m−2. The key conclusion suggests that adding of AC particle into jute fibers/polyester composites can improve their stiffness; meanwhile, their strength and ductility have been sacrificed.

High-performance fibre supercapacitors based on ball-milled activated carbon nanoparticles mixed with pen ink

A flexible coaxial fibre supercapacitor based on ball-milled activated carbon nanoparticles mixed with pen ink as electrode materials was successfully fabricated. With the ball-milling time prolonging, the size distribution of the activated carbon particles became gradually narrowed and the average particle size decreased into tens of nanometres from tens of microns, and some Fe2O3 phases were introduced. The specific capacitance of the ball-milled activated carbons improved. Furthermore, an activated carbon ball-milled for 24 h with a higher specific capacitance was selected to mix with commercial ink in a ratio of 1:20 to prepare a new active material for high-performance coaxial fibre supercapacitors. Consequently, the specific capacitance for the fibre supercapacitor reached 14.5 mF cm−1, which was 16 times more than that using commercial ink alone as the active layer material, and four times than that using ink mixed with the original activated carbon.

Treatment of cyanide wastewater dynamic cycle test by three-dimensional electrode system and the reaction process analysis

ABSTRACT Dynamic three-dimensional electrode system treatment of cyanide wastewater used coal-based electrodes as cathode and anode, activated carbon as particle electrodes, the effects of applied voltage, reaction time and flow rate on ion removal rate were studied. SEM-EDS and XPS were used to study the morphology of coal-based electrode and the composition and existing state of the load substances, and the reaction mechanism were analysed and discussed. The results show that the removal rates of CNT, Cu, Zn, CN−, SCN− in cyanide wastewater were 97.03%, 95.79%, 99.82%, 99.42% and 94.19%, respectively, when the applied voltage of 4 V, the electrode distance of 10 mm, the flow rate of 30 ml/min, the reaction time of 2.5 h and the dosage of activated carbon particles of 2 g. The applied voltage is the key factor affecting ion removal. When the voltage was 2 V, the ion removal is mainly due to the synergistic effect of chemisorption and electrosorption. The CN−, SCN−, and metal cyanide complex anions in wastewater migrate to the anode of coal-based anode and particle electrode rapidly under the combined action of electric field and magnetic stirring. On the surface of porous coal-based electrode, the removal of CN−, SCN− was mainly attributed to the oxidation of oxygen evolution from the anode reaction, while the removal of Cu, Zn and other metal ions was mainly by the electrodeposition process on the cathode surface.

Removal of radioactive methyliodide from the gas stream with a composite sorbent based on polyurethane foam

Abstract A composite iodine sorbent was obtained in the form of porous polymer matrix with activated carbon particles impregnated with triethylenediamine deposited on its surface. A comparative assessment of the radioactive methyliodide capturing efficiency by the composite sorbent and a sample of industrial charcoal sorbent was conducted. It was shown that under the selected testing conditions, the hydraulic resistance of the composite sorbent is lower, and the sorption capacity is higher than that of the industrial charcoal sorbent. A method for comparing the effectiveness of iodine sorbents, based on the calculation of the ratio of the sorption capacity index to the minimum capacity index, needed for the required purification degree was proposed.

A single step process to synthesize ordered porous carbon from coconut shells-eggshells biowaste

A novel method is used to synthesize ordered porous carbon from natural bio waste. Eggshells and coconut shells powder particles were used for synthesis of bio carbon. Eggshell particles were used as template as well as activating agent for synthesis of ordered porous carbon, while coconut shells act as a precursor. The synthesized activated carbon particles were characterized with the aid of X-ray diffraction analysis (XRD), Raman spectroscopy, Thermogravimetric analysis (TGA), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Surface area analysis. Adsorption capacity of synthesized ordered porous carbon was investigated with UV–vis spectroscopy. XRD results revealed that the optimum temperature for pyrolysis of eggshell-coconut shell mixture is 800 °C. XRD and Raman analysis confirmed the formation of amorphous carbon. It was observed that 1:1 ratio at 800 °C gave optimum results when compared with 1:2, 1:3 and 1:4 eggshells and coconut shells mixture. Brunauer–Emmett–Teller (BET) surface area and pore volume of 1:1 ratio at 800 °C were found to be 375.4 m2 g−1 and 0.2478 cm3 g−1 respectively. The average pore size was found to be 2.64 nm for 1:1 ratio of eggshells-coconut shells mixture pyrolyzed at 800 °C. Morphology analysis confirms the formation of micropores and mesopores on the surface of carbon particles. The adsorption isotherms were well fitted with Langmuir isotherms. Maximum adsorption capacity was found to be 305.76 mg g−1 for methylene blue adsorption on the surface of ordered porous carbon.

Automated separation and analysis of krypton-85 from low-volume gaseous effluent of nuclear power plant

Based on the requirements of the lower detection limit for the low-volume gaseous effluent, we have designed an automatic separation apparatus of krypton (Kr). The principle of the apparatus is based on both the adsorption and desorption mechanism in the traps with the activated carbon particles and gas chromatography with 5A molecular sieves. The separation efficiency and overall recovery rate could be maintained at about (90.4 ± 4.2)% and (24.3 ± 1.3)%. The 85Kr could be radioassayed on a liquid scintillation counter following the automatic separation and loading into the cryogenic count vial. The detection limit based the low-volume of 3 L is about 9.5 Bq m−3, and the expanded relative uncertainties are in the range of 13–18% for typical measurements.

Enhanced oxygen evolution performance of spinel Fe0.1Ni0.9Co2O4/Activated carbon composites

A series of iron-doped nickel cobalt oxide/activated carbon (Fe0.1Ni0.9Co2O4/AC) composites with various ratios of activated carbon were synthesised via a microwave-assisted hydrothermal method. The introduction of activated carbon significantly promotes the catalytic activity of Fe0.1Ni0.9Co2O4 for the oxygen evolution reaction (OER); meanwhile the complete coverage of nanoparticulate Fe0.1Ni0.9Co2O4 onto activated carbon particles prevents the carbon oxidation, leading to improved cycling durability of a zinc-air cell. Scanning electron microscopy images shows a good protective coverage of the nanoparticulate Fe0.1Ni0.9Co2O4 onto the activated carbon particles. Rotating disk electrode voltammetry and electrochemical impedance spectroscopic results reveal that the OER overpotential and charge-transfer resistance of the Fe0.1Ni0.9Co2O4 electrocatalyst are substantially lowered by the introduction of activated carbon. With respect to the cycling stability, Fe0.1Ni0.9Co2O4/1.0 wt%AC and Fe0.1Ni0.9Co2O4/1.5 wt%AC composites maintain excellent activity for 80 h in a rechargeable zinc-air battery, due to the uniformly protective coverage of metal oxide on activated carbon. Furthermore, the Fe0.1Ni0.9Co2O4/3.7 wt%AC composite was examined in a prolonged rechargeable zinc-air battery test for 120 h and the charge-discharge voltage gap was negligibly enlarged (0.02 V increment after 120 h), which showed their potential as electrocatalysts for long-term energy storage systems.

Adsorption of volatile organic compounds on modified spherical activated carbon in a new cyclonic fluidized bed

Volatile organic compounds (VOCs) are severe environmental pollutants that pose a serious threat to human health. In this study, a new type of cyclonic fluidized bed was designed to carry out absorption of VOCs by activated carbon, in which the collision and adsorption between activated carbon particles and VOC moleculars were enhanced by three-dimensional rotating turbulent shear. We studied the VOC adsorption efficiency of three kinds of modified spherical activated carbon (SAC-1, SAC-2, and SAC-3) and five kinds of cyclonic fluidized bed (S11-44, S11-33, S11-22, S13-22, and S16-22). The pressure drop of the cyclonic fluidized bed under different inlet flow rates, activated carbon dosages, and inlet VOC concentrations were also investigated. The results indicate that smaller inlet flow rate, larger activated carbon dosage, larger diameter and smaller inserted depth of the cyclone fluidized bed overflow pipe will lead to lower pressure drop and higher VOCs adsorption efficiency. The pitch-based SAC-1 and the S16-22 cyclonic fluidized bed had the highest adsorption efficiency (100%) and the lowest pressure drop (120 Pa). This study not only benefits VOC absorption but also serves as a useful guide for the development of cyclone separation technology in industrial processes.

Navy Blue 3G Dye Electrocoagulation using Stainless Steel Electrode in Presence and Absence of Granular Activated Carbon Particle Electrode

Textile or dye wastewater is complex and toxic due to presence of complex chemicals in them hence difficult to treat with conventional biological treatment. This paper presents study of electrocoagulation treatment on simulated Navy Blue 3G dye wastewater using stainless steel electrode material in presence and absence of granular activated carbon as particle electrode. Preliminary test to understand effect of initial influent pH (3-10) and NaCl and Na2SO4 dose (0-2000 mg/L) on the EC process has also been investigated and further work was carried at optimized initial pH and NaCl dose. The results show that at highest studied current density of 10 mA/cm2 with stainless steel electrode showed complete removal of dye concentration after 90 min of treatment time. Electrocoagulation and adsorption using granular activated carbon (GAC)and stainless steel (SS+GAC) are good treatments when dispersed colour is present in the solution. Hence, change in decolourization efficiency of 2D EC was also studied on adding GAC particle electrode between anode-cathode assembly. The effect of current density and dye concentration on colour removal (%) was then studied. Complete removal of colour was observed at lesser time or at more current density; simultaneously initial dye concentration has shown inverse effect on colour removal. Higher removal of around 10 to 15% was reported with SS+GAC compared to SS alone.

Biodegradation of BTEX compounds from petrochemical wastewater: Kinetic and toxicity

The BTEX compounds have potential pollution with serious risk to the environment and human health. In this study, batch and continuous bioreactors, using biofilms supported on activated carbon particles were studied to remove BTEX compounds. The activated sludge from local wastewater treatment plant was adapted to biodegrade BTEX compounds and used in this work. The obtained results showed that the biofilm well adapted with the evaluated conditions and was able to conduct a complete degradation of BTEX compounds. Additionally, particles samples demonstrated higher bacteria content ranging from 79.40 (toluene) to 8.84 mgvss/L (o-xylene) of biomass amount. Kinetic parameters were obtained in a batch bioreactor fed daily with BTEX compounds. The tests showed that the biomass in the bioreactor was able to remove the BTEX compounds up to 300 min showing a potential strategy for the petrochemical industry. In addition, compared to the initial toxicity, after the treatment, a reduction in the acute toxicity up to 99% was observed confirm the potentiality of the proposed system in this study.

Quantification of microbial degradation activities in biological activated carbon filters by reverse stable isotope labelling

Biological activated carbon (BAC) filters are frequently used in drinking water production for removing dissolved organic carbon (DOC) via adsorption of organic compounds and microbial degradation. However, proper methods are still missing to distinguish the two processes. Here, we introduce reverse stable isotope labelling (RIL) for assessing microbial activity in BAC filters. We incubated BAC samples from three different BAC filters (two granular activated carbon- and one extruded activated carbon-based) in a buffer amended with 13C-labelled bicarbonate. By monitoring the release of 12C–CO2 from the mineralization of DOC, we could demonstrate the successful application of RIL in analysing microbial DOC degradation during drinking water treatment. Changing the water flow rates through BAC filters did not alter the microbial activities, even though apparent DOC removal efficiencies changed accordingly. Microbial DOC degradation activities quickly recovered from backwashing which was applied for removing particulate impurities and preventing clogging. The size distributions of activated carbon particles led to vertical stratification of microbial activities along the filter beds. Our results demonstrate that reverse isotope labelling is well suited to measure microbial DOC degradation on activated carbon particles, which provides a basis for improving operation and design of BAC filters.

Study on the treatment of simulated azo dye wastewater by a novel micro-electrolysis filler

A new type of iron-copper-carbon (Fe-Cu-C) ternary micro-electrolysis filler was prepared with a certain proportion of iron powder, activated carbon, bentonite, copper powder, etc. The effect of the new type of micro-electrolysis filler on the simulated methyl orange dye wastewater was studied. The effects of various operational parameters, such as reaction time, initial pH value, aeration rate, filler dose and reaction temperature, on the degradation rate of methyl orange were studied to determine the optimum treatment conditions, and the micro-electrolysis filler was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The experimental results show that the degradation rate of 220 mL of simulated dye wastewater with a concentration of 100 mg/L reached 93.41% ± 2.94% after 60 mL/min of aeration, with an initial pH = 2, a dose of 45 g and 125 minutes of reaction at room temperature. The new micro-electrolysis filler has a high degradation rate for methyl orange solution, which is attributed to the iron and activated carbon particles sintered into an integrated structure, which makes the iron and carbon difficult to separate and affects the galvanic cell reaction. The addition of copper also greatly increases the transmission efficiency of electrons, which promotes the reaction. In addition, the surface iron is consumed, the adjacent carbon is stripped layer by layer, and the new micro-electrolytic filler does not easily passivate and agglomerate during its use.

Packing Activated Carbons into Dense Graphene Network by Capillarity for High Volumetric Performance Supercapacitors.

Supercapacitors are increasingly in demand among energy storage devices. Due to their abundant porosity and low cost, activated carbons are the most promising electrode materials and have been commercialized in supercapacitors for many years. However, their low packing density leads to an unsatisfactory volumetric performance, which is a big obstacle for their practical use where a high volumetric energy density is necessary. Inspired by the dense structure of irregular pomegranate grains, a simple yet effective approach to pack activated carbons into a compact graphene network with graphene as the “peels” is reported here. The capillary shrinkage of the graphene network sharply reduces the voids between the activated carbon particles through the microcosmic rearrangement while retaining their inner porosity. As a result, the electrode density increases from 0.41 to 0.76 g cm−3. When used as additive‐free electrodes for supercapacitors in an ionic liquid electrolyte, this porous yet dense electrode delivers a volumetric capacitance of up to 138 F cm−3, achieving high gravimetric and volumetric energy densities of 101 Wh kg−1 and 77 Wh L−1, respectively. Such a graphene‐assisted densification strategy can be extended to the densification of other carbon or noncarbon particles for energy devices requiring a high volumetric performance.

Electrochemical removal of nitrate by Cu/Ti electrode coupled with copper-modified activated carbon particles at a low current density.

Electrochemical reduction is currently one of promising methods for nitrate removal from water, yet most treatment approaches have problems of high cost and energy consumption. In this work, a low current density was applied in electrochemical reduction of nitrate. Copper-modified titanium (Cu/Ti) electrodes with optimal electrochemical activity and fastest kinetics were firstly screened. Thirty minutes of electrodeposition time and neutral pH were found to have the greatest nitrate reduction rate of 83.14%. To further improve the removal of nitrate, activated carbon (AC) and copper-modified activated carbon (Cu/AC) particles were applied to construct three-dimensional reaction systems, with removal rates of nitrate of 88.72% and 96.05%, respectively. The average conversion rates of nitrate to ammonia nitrogen increased from 15.28% to 42.68% and 62.64% in AC- and Cu/AC-based reaction systems, respectively. Oxidation of Cu(0) on surfaces of Cu/Ti cathode and Cu/AC particles to Cu(I) was revealed by X-ray photoelectron spectroscopy (XPS) and Cu LMM spectra analysis. Besides, results of water chemistry characteristics indicated the conversion of AC to carbonate ion. It could be concluded that enhanced nitrate reduction of Cu/Ti-based reaction system was attributed by Cu particle- and AC-mediated electron transfer. This study provided a reference for low-cost electrochemical reduction of nitrate.

Activated carbon-supported catalyst loading of CH4N2O for selective reduction of NO from flue gas at low temperatures

Selective catalytic reduction of nitrogen oxides with loaded CH4N2O (low-temperature urea-SCR) is a novel and promising technology to remove nitrogen oxides from low-temperature oxygen-containing flue gas, which can avoid the problem of NH3 escape. In the present study, a series of industrial-grade biomass-based activated carbon (AC)-supported transition metal oxide catalysts with urea loading were prepared by ultrasound-assisted impregnation, and the physicochemical properties of the catalysts were observed by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), graphite furnace atomic absorption spectroscopy (GFAAS), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) analysis, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The influences of the AC type, reaction temperature, AC particle size, metal oxide loading, urea load level and loaded active element type on the catalytic activity were studied through experiments. Moreover, the NO adsorption capacities of the AC carrier at different temperatures were also tested and calculated. The results of NO adsorption tests show that the adsorption capacity of AC decreased with increasing temperature. The results of the catalytic performance tests indicate that the copper- and manganese-based catalysts with 6 wt% urea exhibited better activity than the other catalysts. The copper-based catalyst, in particular, yielded better than 93% NO conversion at low temperatures (50–100 °C). Finally, on the basis of the combined characterization results and thermodynamics analysis, a NO removal mechanism of the copper- and manganese-based catalysts was proposed and discussed; the electron transfers of Mn4+ ⇌ Mn2+ and Cu2+ ⇌ Cu0 promoted the low-temperature urea-SCR method.

Preparation of fibrous electrospun membranes with activated carbon filler

Immiscible solvents blend suspensions applied to produce fibrous polymer membranes heavy filled with activated carbon (AC) particles by electrospinning method. The continuous phase of the suspension is a solution of polyacrylonitrile (PAN) in polar solvent (dimethylsulfoxide (DMSO)), the dispersed phase is suspended in non-polar solvent (hexane) AC particles. An ionic liquid 1-ethyl-3-methylimidazolium acetate (EmimAc) added to both phases to improve the electrospinning process and enhance the electrical conductivity of the electrospun mat. These types of membranes developed as electrode materials for energy storage devices.In this study, we obtain electrospun membranes with up to 60 wt.% of activated carbon content, AC particles are connected between each other by PAN nanofibers, and covered with PAN nanofibrous mesh.

Activated carbon dispersion as absorber for solar water evaporation: A parametric analysis

Solar water evaporation has been a topic of interest in recent years due to its applications in desalination, power generation, and heating. As water is not a good absorber of light, seeding it with light-absorbing particles can enhance evaporation efficiency. Activated carbon (AC) is one such material with desirable absorption properties for this application. However, particle sizes in granular and powder activated carbon can vary significantly. In this work, AC particles of different sizes are analyzed and their effect on evaporation rate is studied. It is found that particle sizes less than or comparable to solar wavelength spectrum produce higher evaporation efficiencies under independent scattering conditions (fv<0.6%). It is also found that the solar absorption coefficient reaches between 0.98 and 0.9 for a volume fraction as low as 0.01%. The evaporation efficiency is 57.3% and 38.2% higher than for pure water evaporation for size of 80 nm and 8 μm, respectively, for a volume fraction of 0.01%. A parametric analysis is performed to identify the respective effect on evaporation rate.

Synthesis of Biomass-Derived Nitrogen-Doped Porous Carbon Nanosheests for High-Performance Supercapacitors

Graphene-like two-dimensional carbon nanosheets with properly modulated compositions and porosity are of particular importance for robust capacitance harvesting. Nevertheless, the large-scale and cost-effective production of such nanostructures still remains a great challenge. Herein, we innovatively produce nitrogen-doped porous carbon nanosheets using pine nut shells, an abundant biomass waste, as the precursor, under the synergetic effect of KOH and melamine during the activation process. The sole activation of the precursors with KOH can produce only traditional activated carbon particles of several micrometers, while interestingly, the extra introduction of melamine results in nitrogen-doped porous carbon nanosheets possessing high tunability. By construction of a two-electrode configuration, the supercapacitors with optimal nanosheets as the electrode materials can deliver a superior specific capacitance of 324 F g –1 at 0.05 A g–1, outstanding rate capability of 258 F g–1 at 20 A g–1, and extraordi...

Implication of Non-electrostatic Contribution to Deionization in Flow-Electrode CDI: Case Study of Nitrate Removal From Contaminated Source Waters.

While flow-electrode capacitive deionization (FCDI) operated in short-circuited closed cycle (SCC) mode appears to hold promise for removal of salt from brackish source waters, there has been limited investigation on the removal of other water constituents such as nitrate, fluoride or bromide in combination with salt removal. Of particular concern is the effectiveness of FCDI when ions, such as nitrate, are recognized to non-electrostatically adsorb strongly to activated carbon particles thereby potentially rendering it difficult to regenerate these particles. In this study, SCC FCDI was used to desalt source waters containing nitrate at different concentrations. Results indicate that nitrate can be removed from source waters using FCDI to concentrations <1 mg NO3-N L−1 though a lower quality target such as 10 mg L−1 would be more cost-effective, particularly where the influent nitrate concentration is high (50 mg NO3-N L−1). Although studies of the fate of nitrate in the FCDI system show that physico-chemical adsorption of nitrate to the carbon initially plays a vital role in nitrate removal, the ongoing process of nitrate removal is not significantly affected by this phenomenon with this lack of effect most likely due to the continued formation of electrical double layers enabling capacitive nitrate removal. In contrast to conventional CDI systems, constant voltage mode is shown to be more favorable in maintaining stable effluent quality in SCC FCDI because the decrease in electrical potential that occurs in constant current operation leads to a reduction in the extent of salt removal from the brackish source waters. Through periodic replacement of the electrolyte at a water recovery of 91.4%, we show that the FCDI system can achieve a continuous desalting performance with the effluent NO3-N concentration below 1 mg NO3-N L−1 at low energy consumption (~0.5 kWh m−3) but high productivity.

Characterization of Silver Loaded Activated Carbon Prepared under Supercritical Water Condition

The synthesis of silver nanoparticles loaded on the activated carbon (AC) surface were performed under SCW condition at 673 K and 31.15 MPa in a batch reactor. In supercritical region, fine particles are rapidly synthesized due to reaction rate increase at low dielectric constant of supercritical water. Samples were prepared with different concentrations of silver acetate solution and various reaction times. The synthesized silver loaded on AC particles were characterized by the Fourier transform infrared spectroscopy (FTIR),X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). FTIR spectrum of primary activated carbon, activated carbon treated under supercritical water condition and synthesized AC-Ag was compared. The particles size and crystallite size of silver deposited on AC surface were analyzed by TEM and XRD, respectively.