Activated Carbon Particles Research Articles

Polydimethylsiloxane-coated macroporous silica adsorbent in thermal desorption gas chromatography

Polydimethylsiloxane (PDMS)-coated macroporous silica (MPSi) particles were developed for the extraction of volatile organic compounds (VOCs) from air samples in thermal desorption-gas chromatographic analysis. The gas sample was collected by a gas sampling pump at 100 mL/min. Different amounts of PDMS coating were prepared, and the fundamental extraction and desorption performances were investigated using even numbered n-alkanes of C8–C28. The extraction efficiency increased by increasing PDMS coating, and the desorption efficiency showed more than 99% at a desorption temperature of 310°C for all the investigated adsorbents. This remarkable desorption performance showed a higher peak area of the analytes than that of the Tenax TA-packed thermal desorption tube, especially for higher molecular weight compounds. Furthermore, an activated carbon particle of Carbopack X was introduced on the latter side of the PDMS-MPSi to extract low-molecular weight compounds. This double-bed-type extraction tube showed a successful determination of a wide range of VOCs. The double-bed-type extraction tube was then applied to the extraction of VOCs related to sick building syndrome (SBS). The results for the extraction and desorption performances of the SBS-related VOCs were well agreed with that of alkanes, and the applicability of the extraction tube to the determination of other types of conventional VOCs were confirmed.

Development of an activated carbon‐geopolymer composite for treatment of Pb(II) polluted water and soil

AbstractAn activated carbon‐geopolymer composite (ACGC) was prepared by using fly ash as raw materials via a simple geopolymerization process for treating the Pb(II) contaminant in wastewater and soil. The phase composition, microtopography, pore structure, and surface groups of the composites were studied by X‐ray diffractometer, field emission scanning electron microscopy, X‐ray photoelectron spectroscopy, N2 adsorption‐desorption isotherm, and Fourier transform infrared spectroscope. It was discovered that there was a synergistic effect between geopolymer matrix and activated carbon (AC), that is, addition of AC particles could increase the pores in geopolymer while strong alkalis condition provided by geopolymer enhanced the contents of oxygenic groups of AC. When the composite was used as the adsorbent, the sample containing 20 wt% AC (40ACGC) showed the maximum adsorption capacity (319.72 mg/g), and its adsorption isotherm fitted the Langmuir model well, suggesting the monolayer adsorption of Pb2+ on the 40ACGC. The kinetics of Pb2+ adsorption on the 40ACGC belonged to the pseudo‐second‐order model, indicating that Pb2+ adsorption on the composite followed chemical adsorption. In addition, the 40ACGC sample showed excellent stabilization performance for Pb2+ in soil. This work offered a new thinking to the application of geopolymers into remediation of heavy metal‐polluted soil.

Ultra-high-efficiency capture of lead ions over acetylenic bond-rich graphdiyne adsorbent in aqueous solution

A satisfactory material with high adsorption capacity is urgently needed to solve the serious problem of environment and human health caused by lead pollution. Herein, hydrogen-substituted graphdiyne (HsGDY) was successfully fabricated and employed to remove lead ions from sewage and lead-containing blood. The as-prepared HsGDY exhibits the highest adsorption capacity of lead among the reported materials with a maximum adsorption capacity of 2,390 mg/g, i.e., ~five times larger than that of graphdiyne (GDY). The distinguished hexagonal hole and stack mode of HsGDY allows the adsorption of more lead via its inner side adsorption mode in one single unit space. In addition, the Pb 6s and H 1s hybridization promotes the strong bonding of lead atom adsorbed at the acetylenic bond of HsGDY, contributing to the high adsorption capacity. HsGDY can be easily regenerated by acid treatment and showed excellent regeneration ability and reliability after six adsorption-regeneration cycles. Langmuir isotherm model, pseudo second order, and density functional theory (DFT) demonstrated that the lead adsorption process in HsGDY is monolayer chemisorption. Furthermore, the HsGDY-based portable filter can handle 1,000 μg/L lead-containing aqueous solution up to 1,000 mL, which is nearly 6.67 times that of commercial activated carbon particles. And, the HsGDY shows good biocompatibility and excellent removal efficiency to 100μg/L blood lead, which is 1.7 times higher than that of GDY. These findings suggest that HsGDY could be a promising adsorbent for practical lead and other heavy metal removal.

Effect of Activated Carbon Particle Size on Methylene Blue Adsorption Process in Textile Wastewater

Up to 60–70% of the total textile dyes produced are azo dyes. An example of azo dye is methylene blue, which is commonly used in dyeing wool, silk, and cotton. This substance possessed harmful effects on the environment. Therefore, the removal process is mandatory. The adsorption process is a common method for dye removal in wastewater. One innovation to increase adsorption efficiency even further is by reducing adsorbent particle size. To understand the effect of adsorbent particle size on the adsorption process, in this study, granular activated carbon (GAC) was pulverized into powder (PAC) and superfine powder (SPAC). Adsorbent characterizations, isotherm, kinetics, and thermodynamics tests were conducted. Based on this study, surface area, pore volume, and adsorption capacity were increased for smaller adsorbent particle sizes. Isotherm and kinetic analysis showed that there was no difference in the isotherm and kinetic models that applied to each activated carbon, but there was an increase in the isotherm and kinetic coefficient values at smaller particle sizes. Meanwhile, based on the thermodynamic test, there were differences in the dominant adsorption mechanism for each activated carbon. In GAC and SPAC, the dominant adsorption mechanism was electrostatic interactions, while in PAC was van der Waals forces.

Analysis of the live weight dynamics of male turkeys when using eubiotics based on bifidobacteria of Bifidobacterium bifidum strain in the diet

In poultry farming, in order to increase the productivity and livability of poultry stock, antibiotics and biologically active compounds are used as feed additives, which, along with positive properties, cause pathological changes. On this basis, the aim of the research was to determine the effects of various doses of medications based on bifidobacteria on productivity, to find out whether the factor of belonging to a particular subgroup affects the average value of live weight in this subgroup and to conduct a pair comparison of live weight values in subgroups on the principle of “round-robin”. In the diet of turkeys of the first three experimental groups, medication No. 1 – an eubiotic, containing live bifidobacteria of Bifidobacterium bifidum strain was added; the turkeys of the rest three experimental groups received medication No. 2 – an eubiotic, containing live, lyophilized Bifidobacterium bifidum cells sorbed on activated carbon particles. The results of the variance analysis showed that at the age of 4 weeks, the factor of belonging of turkeys to a particular group had a significant impact on the value of the live weight of animals. Then, at the age of 8 weeks, the situation changed. In groups from II to VII, there was practically no significant difference in the average values of live weight. Only the control group I was singled out. At the age of 12 and 16 weeks, male turkeys of the II, III, V, VI groups, where eubiotics based on bifidobacteria were used, gradually began to stand out in a big way. This trend continued until the 24th week. It has been established that medications, which contain bifidobacteria, have a great potential to increase the productivity of poults due to the activation of metabolic processes in the body. The most pronounced effect has biopreparation No. 2.

In-situ detoxification and enhanced oxygen mass transfer for C5 sugar acid production from corncob hemicellulose hydrolysates using activated carbon particles

In this work, an easily implemented and cost-effective activated carbon (AC) enhanced technique was proposed for C5 sugar acid production from corncob hemicellulose hydrolysates. The optimum AC detoxification conditions were obtained by response surface methodology, and the fermentation kinetics behaviors were comparatively evaluated using two fermentation modes: separate detoxification and fermentation (SDF) and in-situ detoxification and fermentation (In-situDF). An investigation of the AC function demonstrates it offers synchronous detoxification and oxygen transfer enhancement, with a final increase of XA fermentation yield and productivity. This study shows a potential of detoxification and oxygen transfer enhancement in one-pot in C5 sugar acid production, which may smooth the way for commercial utilization of C5 sugars from lignocellulosic biomass in the future.

Preparation of Granular Activated Carbon Particle Electrode Loaded with Co3O4 and its Effect on Amoxicillin Wastewater Treatment

In this work, granular activated carbon (GAC) loaded with Co3O4 catalyst (Co3O4/GAC) was used as a particle electrode for three-dimensional (3D) electrochemical treatment of amoxicillin (AMX) wastewater. The morphology, crystal structure, surface chemical bonds, specific surface area, and pore structure of the particle electrodes were characterized. Considering AMX and TOC removal rates and electrical energy consumption (EEC), the optimal manufacturing conditions of the Co3O4/GAC were determined as the calcination temperature of 700 °C, the calcination time of 5 h, and the impregnation time of 3 h, respectively. The measurement of electrochemical impedance spectroscopy showed that the interfacial electron transfer property of Co3O4/GAC was much improved compared with GAC. AMX removal rate (96.0%, 40 min), TOC removal rate (84.4%, 2 h), and EEC (87.2 kWh kg−1 TOC) of the 3D-Co3O4/GAC system were all significantly improved compared to the 3D-GAC system (77.9%, 40.3%, 232.9 kWh kg−1 TOC) and the 2D system (66.4%, 3.9%, 2080.3 kWh kg−1 TOC) under the same operating conditions. It was confirmed that Co3O4/GAC catalytically generates ·OH and H · radicals and increases the conductivity inside the reactor. The degradation of AMX was confirmed using ultraviolet-visible spectroscopy and the degradation mechanism of AMX in the 3D-Co3O4/GAC system was proposed.

Nano α-Fe2O3 Self-Assembled Hybrid Biofilm Boosts Hydrogen Autotrophic Denitrification in a Three-Dimensional Biofilm Electrode Reactor

The performance of three-dimensional biofilm electrode reactors (3D-BERs) in hydrogen autotrophic denitrification is determined by electroactive biofilms. Herein, a self-assembled hybrid biofilm (SAHB) is developed on granular activated carbon particle electrodes by incorporating nano α-Fe2O3. The influences of operating parameters such as current, influent concentration, and hydraulic retention time (HRT) on denitrification are investigated as well as the mechanisms of SAHB-improved denitrification. The results indicate that SAHB achieves a high autotrophic denitrification rate of 4.20 mg TN/L/h under 40 mA current, 100 mg/L nitrate, and 26 h HRT, outperforming the naturally formed biofilm by 23.53%. SAHB contains more microorganisms than naturally formed biofilms, revealing that nano α-Fe2O3 is conducive to trapping free microorganisms on particle electrodes. SAHB enriches denitrification-related genes and increases corresponding enzyme activities (particularly nitrite reductase). According to metagenomic sequencing, nano α-Fe2O3 addition at a current level of 40 mA appears to favor denitrification via the nirS-dependent pathway probably due to its high affinity for cytochrome C. Metagenomic binning reveals that the microorganism associated with Zoogloeaceae (Rhodocyclales order) in SAHB may play a pivotal role in hydrogen autotrophic denitrification. This work develops a novel denitrification system, furthering our understanding of hydrogen autotrophic denitrification in 3D-BERs.

Study on the performance of fuel cell air filter with different carbon content

Fuel cell air filter can absorb harmful impurities and gases to fuel cell and is an important component to ensure the service life of fuel cell. The previous researches mainly focus on the activated carbon and filter paper materials in the laboratory. The object of this paper is the fuel cell air filter product assembly being used by the main engine plant. According to the tests of air filters with different carbon contents, it was found that the adsorption efficiency of current products for NO2 was better than that of C7H8, SO2 and C4H10. Based on the adsorption mechanism of activated carbon for different gases, the adsorption difference was explained. The testes also found that there was no direct relationship between the change of carbon content of products containing activated carbon and the fractional filtration efficiency. The main reason is that the gap between the activated carbon particles is large, which cannot effectively intercept dust particles. The filtering of small size particles still depends on the melt-blown layer material in the air filter element and its electrostatic electret process. It was also found that there was a positive correlation between inlet air resistance and carbon content, and a negative correlation between dust holding capacity and carbon content. This test results can help the main engine factory understand the performance and improvement direction of products.

Optimised synthesis of stainless steel fibre-entrapped activated carbon composites using response surface methodology

Stainless steel fibre-entrapped activated carbon composites (SFEACs) can enhance mass and heat transfer processes by entrapping activated carbon particles with well-developed pore structures, but the activated carbon adhesion ability and mechanical strength are poor. In this paper, response surface methodology was used to optimise the synthesis parameters of SFEACs. Using optimized synthesis conditions with sintering temperature of 1120 °C, particle size of 100–120 mesh and carbon to fibre ratio of 1.98, the activated carbon reached a high loading rate of 62.02 %. The rate of carbon loss by severe vibration was only 2.28 % under these conditions, with a tensile strength of 0.31 MPa and shear strength up to 0.035 MPa.

Integration of rare earth element stimulation, activated carbon adsorption and cell immobilization in ABE fermentation for promoting biobutanol production

The objective of this work was to promote biobutanol production by integrating rare earth element stimulation, activated carbon adsorption and cell immobilization into acetone-butanol-ethanol fermentation. Among eight selected rate earth elements, the trace supplement of gadolinium (Gd(III)) into fermentation medium (1 × 10−5 M) could significantly stimulate cell growth and biobutanol biosynthesis. Subsequently, activated carbon particles had been used to alleviate biobutanol toxic effect for bacterial cells. The adsorption of biobutanol on activated carbon particles was coincident with Pseudo-first-order dynamics and Freundlich isotherm models. In order to prevent the competitive adsorption between bacterial cells and biobutanol on activated carbon particles, bacterial cells bad been immobilized on the surface of volcanic stones. After cultivating for 5 h, activated carbon particles were introduced into fermentation broth for performing biobutanol isolation. Finally, the total biobutanol yield using the developed strategy was 15.26 ± 0.43 g/L, which was 73.20 ± 12.69% higher than that of common fermentation with free bacterial cells.

Ex-situ magnetic activated carbon for the adsorption of three pharmaceuticals with distinct physicochemical properties from real wastewater.

Pharmaceuticals are able to evade conventional wastewater treatments and therefore, are recurrently found in the environment with proven potential to cause harm to human and wildlife. Adsorption onto activated carbon (AC) is a promising complement. However, AC production from non-renewable resources and its difficult after-use recuperation are prohibitive. Hence, a waste-based magnetic activated carbon (MAC) was produced from paper mill sludge, via an ex-situ synthesis, for the adsorptive removal of carbamazepine (CBZ), sulfamethoxazole (SMX) and ibuprofen (IBU) from ultrapure water and wastewater. The MAC was obtained through the promotion of electrostatic interactions between magnetic and activated carbon particles in a water suspension at controlled pH between the points of zero charge of both surfaces. The optimized condition (MACX3) presented remarkable properties regarding specific surface area (SBET=795m2 g-1) and saturation magnetization (MS=19emug-1). Kinetic and equilibrium adsorption studies were performed under batch conditions. Adsorption equilibrium was reached in up to 30min for all pharmaceuticals in both matrices, proving the low dependence on the adsorbate and the broad applicability of MACX3 in pharmaceutical adsorption. Regarding equilibrium experiments, high Langmuir maximum adsorption capacities (qm) were achieved in ultrapure water (up to 711 ± 40 µmol g-1). Equilibrium studies in wastewater revealed a decay in qm when compared to ultrapure water: 28% for CBZ (468 ± 20 µmol g-1 (111 ± 5 mg g-1)), 78% for SMX (145±10 µmol g-1 (37 ± 3 mg g-1)) and 62% for IBU (273 ± 8 µmol g-1 (56 ± 2 mg g-1)), attributed to the wastewater pH, which dictates the speciation of the pharmaceuticals and controls electrostatic interactions between pharmaceuticals and MAC, and to competition effects by organic matter. It was demonstrated the promising applicability of a waste-based ex-situ MAC, rapidly retrievable from water, as an alternative tertiary wastewater treatment for pharmaceuticals removal.

Effect of the Sorption Layer on the Protection Time Provided by Anti-Smog Half-Masks.

This paper presents the results of a study examining the protection time of half-masks containing different types and quantities of carbon sorbents. The protection time afforded by the half-masks was determined by analyzing the adsorption of three substances harmful to human health at their maximum allowable concentrations. Two of the tested half-masks showed comprehensive protection against pollutants contained in smog. Among the tested half-masks, the one with the best protective properties was identified. The longest protection time (over 8 h) was recorded for toluene, followed by over 7 h for sulfur dioxide, and only 2 h for cyclohexane. The morphological structure of nonwovens incorporating the carbon sorbents was examined under a microscope. The study showed that protection time depends on the size of activated carbon particles incorporated in the nonwoven structure as well as on their distribution. Based on these results, we identified the most effective morphological structure of the sorbent in the nonwovens.

Numerical prediction of pressure drop and flow characteristics of activated carbon and salt-water for flow-electrode capacitive mixing (F-CapMix)

In flow-electrode capacitive mixing (F-CapMix), prediction of the flow characteristics and pressure drop of the flow-electrode is important as it pertains to both efficient charge percolation and electron transport of activated carbons in the flow-electrode, as well as the net power of F-CapMix. In this study, the flow characteristics and pressure drop of activated carbon and salt-water within the flow-electrode of F-CapMix are predicted by applying numerical simulations, when the channel depth for the flow-electrode is changed from 0.5 mm to 2.5 mm. The numerical simulation was validated by comparing the experimental results of pressure drop measurements of the flow-electrode. To analyze the variables related to electron transfer between the activated carbon and the current collector, the particle wall normal pressure was numerically calculated. As the channel depth for the flow-electrode decreased by 0.5 mm, the pressure exerted by the activated carbon particle on the wall increased by 32.92 % on average. Consequently, the power density of F-CapMix increased to 14.03 % owing to the elevated pressure at the wall. Predicting the behavior of activated carbon and the pressure drop through numerical simulation is a key step for the designing of the flow channel for the F-CapMix.

Enhanced norfloxacin degradation by three-dimensional (3D) electrochemical activation of peroxymonosulfate using Mn/Cu co-doped activated carbon particle electrode

In this study, Mn/Cu co-doped activated carbon (MCAC) particle electrodes were applied in the three-dimensional (3D) electrical activation of peroxymonosulfate process (E-PMS-MCAC) for norfloxacin (NOF) degradation. Several comparative experiments demonstrated a significant synergy between catalytic and electric activation of PMS in the E-PMS-MCAC process, which could obtain 90.81 % of NOF removal within 60 min. Quenching experiments and EPR analyses revealed thatSO4·-, •OH, 1O2, and reactive Mn(III) were all involved in the E-PMS-MCAC process, while •OH was dominant reactive species for NOF degradation. The different generation ways of reactive species were also explored. Besides, multiple degradation pathways of NOF were proposed, and the toxicity of intermediates was assessed as well. The characterizations of SEM, XRD, and XPS indicated that the cathodic reduction reaction could facilitate electron transfer to Mn(IV), Mn(III), and Cu(c), triggering the sustainable Mn(I)/Mn(III)/Mn(IV) or Cu(I)/Cu(II) redox cycle. It was noted that the addition of Cl- enhanced the NOF removal, while the presence of HCO3-, NO3-, and H2PO4- inhabited it. Finally, the removal efficiencies of other contaminations including p-nitrophenol (PNP), carbamazepine (CBZ), sulfamethoxazole (SMX), and tetracycline hydrochloride (TCH) were also investigated in the E-PMS-MCAC process. All above results suggested that the E-PMS-MCAC process was a high-efficiency and sustainable technology for organic wastewater treatment.

The Effect of Graphite and Activated Carbon as Dispersed Particle in Base Fluid as Quench Medium on the Hardness of S45C Carbon Steel

Adding a solid particle dispersion into a base fluid could increase its thermal conductivity, hence increasing the heat transfer characteristics. One example of this thermally enhanced fluid is in heat treatment industry as quench medium. By controlling the amount of the dispersed particle, the cooling rate of the quench medium can be altered, and could affect steel hardness after heat treatment. In this research, the dispersed particle used was commercially available graphite and activated carbon particle. As for the base fluid, distilled water and common engine oil were compared. The concentration of the dispersed particle was 0.1, 0.3, 0.5 weight percent. The highest hardness was achieved at 728 HV on the 0.1% activated carbon particle in water base fluid. Meanwhile, by using graphite, the highest hardness achieved was at 639 HV on the 0.1% particle in water base fluid. The result may suggest that activated carbon could improve the cooling rate better due to its impurities. As expected, quenching by dispersed graphite particle in oil based resulted in lower hardness on all variables.

New Magnetically Assembled Electrode Consisting of Magnetic Activated Carbon Particles and Ti/Sb-SnO2 for a More Flexible and Cost-Effective Electrochemical Oxidation Wastewater Treatment

Magnetic activated carbon particles (Fe3O4/active carbon composites) as auxiliary electrodes (AEs) were fixed on the surface of Ti/Sb-SnO2 foil by a NdFeB magnet to form a new magnetically assembled electrode (MAE). Characterizations including cyclic voltammetry, Tafel analysis, and electrochemical impedance spectroscopy were carried out. The electrochemical oxidation performances of the new MAE towards different simulated wastewaters (azo dye acid red G, phenol, and lignosulfonate) were also studied. Series of the electrochemical properties of MAE were found to be varied with the loading amounts of AEs. The electrochemical area as well as the number of active sites increased significantly with the AEs loading, and the charge transfer was also facilitated by these AEs. Target pollutants’ removal of all simulated wastewaters were found to be enhanced when loading appropriate amounts of AEs. The accumulation of intermediate products was also determined by the AEs loading amount. This new MAE may provide a landscape of a more cost-effective and flexible electrochemical oxidation wastewater treatment (EOWT).

Activated carbon paper as ethylene adsorber

Abstract The use of activated carbon with KMnO4 activators incorporated on the paper matrix is carried out in this research. Three methods of activated carbon incorporation on paper are carried out to evaluate the paper’s physical parameters and adsorption ability to ethylene. The paper’s physical parameters include grammage, bursting strength, Ring Crush Test (RCT), moisture content, water absorption (Cobb60), and paper microstructures using SEM. Evaluation of the performance of activated carbon paper nanopores as ethylene adsorbent is conducted using GC. The treatment of activated carbon nanopores on non-wood paper causes grammage to increase, but RCT and paper bursting strength decrease. The incorporation of nanopore-activated carbon by the mixing method has produced papers with activated carbon particles spread evenly inside the pulp fibers of the paper. Activated carbon paper with the best adsorption capacity is bamboo+KMnO4&mixing with an adsorption capacity of 1,348 ppm and ethylene amount of 88.58 %. Concentration equilibrium is reached in the 25th minute. The non-linear pseudo-first-order absorbent kinetics model is an appropriate model to describe the equilibrium capacity of ethylene entrant (qe) by nanopore-activated carbon paper with the equation: qt = 1.35734 ( 1 − exp − 0.15312 t ) \mathrm{qt}=1.35734\hspace{0.1667em}(1-{\exp ^{-0.15312\hspace{0.1667em}\mathrm{t}}}) , with R 2 = 0.9981 {\mathrm{R}^{2}}=0.9981 .

Superhydrophobic/superoleophilic modified melamine sponge for oil/water separation

In this work, an environmentally friendly, superhydrophobic and durable modified melamine sponge was fabricated through a simple two-step dipping method. Through this strategy, the active carbon (AC) particles and reduced graphene oxide (rGO) were fixed on the melamine sponge skeleton with polydimethylsiloxane (PDMS) glue to form MS/rGO/AC/PDMS sponge, which has a multi-stage pore structure. Water contact angle (WCA) revealed that the as-prepared sponge possessed excellent water repellency up to 164°. Being applied in the field of oil/water separation, MS/rGO/AC/PDMS exhibited excellent oil-water selectivity, high oil sorption ability up to 120 g/g, and separation efficiency of over 99.85%. It is worth noting that under complex environments such as acid-base, fatigue and abrasion, the obtained sponge can maintain original properties, and the water contact angle exceeds 154°. In addition, it has good mechanical stability which can be reused and recovered continuously, making it a potential material for practical applications.

Oxygen mass transfer enhancement by activated carbon particles in xylose fermentation media.

In this work, the effect of activated carbon particles on the production of xylonic acid from xylose by Gluconobacter oxydans in a stirred tank bioreactor was investigated. The enhancement of the oxygen transfer coefficient by activated carbon particles was experimentally evaluated under different solids volume fractions, agitation and aeration rates conditions. The experimental conditions optimized by response surface methodology (agitation speed 800rpm, aeration rate 7 L min-1, and activated carbon 0.002%) showed a maximum oxygen transfer coefficient of 520.7h-1, 40.4% higher than the control runs without activated carbon particles. Under the maximum oxygen transfer coefficient condition, the xylonic acid titer reached 108.2g/L with a volumetric productivity of 13.53g L-1h-1 and a specific productivity of 6.52g/gx/h. In conclusion, the addition of activated carbon particles effectively enhanced the oxygen mass transfer rate. These results demonstrate that activated carbon particles enhanced cultivation for xylonic acid production an inexpensive and attractive alternative.