Types Of Carbonaceous Materials Research Articles

Evolution of Holes and Cracks in Pre-Carbonized Glassy Carbon.

Being a type of carbonaceous material, glassy carbon possesses thermomechanical properties akin to ceramics, offering both mechanical and chemical stability at high temperatures; therefore, it can be applied in electrochemistry and high-temperature manufacturing. However, the direct pyrolysis of a bulk precursor leads to internal pores and cracks, usually resulting in fracture. Our characterization results show that at temperatures below 400 °C, large pores do not form, and pre-carbonized glassy carbon (PGC) formed at 350 °C has a dense microstructure without cracks. It exhibits a high compressive strength of ~370 MPa and flexural strength of ~190 MPa, making it suitable for load-bearing applications. Additionally, the PGC-350 material shows small mass loss (~5%) and reasonably low thermal expansion (2.5 × 10-6/°C) when heated to 350 °C again. These properties suggest the potential of PGC for high-temperature applications. As a demonstration, PGC formed at 350 °C was employed to fabricate molds to press chalcogenide glass blanks, which exhibited favorable molding results for various surface morphologies.

Nanofibrous filtering membranes modified with sucrose-derived carbonaceous materials for adsorption in batch and fixed bed

Membrane technologies have been considered as an efficient and economical alternative to help providing clean water for the population on a large scale. In this regard, the development of low-cost adsorbent membranes, with scalable production and high efficiency is indeed necessary and urgently required. In this work, we investigated the methylene blue removal performance of solution blow spun (SBS) polyamide 6 (PA6) nanofibrous membranes (NFMs) coated with different types of carbonaceous materials. Sucrose was employed as carbon source and two distinct approaches, namely hydrothermal and caramelization routes, were investigated to produce it. The NFMs were functionalized by dip-coating and then chemically activated using NaOH to further enhance the adsorption efficiency. The carbonaceous materials-modified NFMs were characterized by scanning electron microscopy (SEM), contact angle, Zeta potential, Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). Batch and fixed bed experiments revealed that the NFMs modified by dip coating with the carbonaceous materials present competitive adsorption capacity in addition to be a simple, low cost and scalable strategy. The experimental and maximum adsorption capacities of batch adsorption were 371.69 mg/g and 471.58 mg/g for the NFMs modified with hydrothermal carbon, and 260.52 mg/g and 651.04 mg/g for the NFMs coated with black caramel, respectively. The NFMs modified with hydrothermal carbon and caramel carbon showed applicability in scalable systems based on fixed bed adsorption experiments. Our results suggest that nanofibrous membranes coated with carbonaceous materials from sucrose are a suitable tool to develop adsorptive membranes for pollutants removal and open the venue to also explore other carbon-rich sources, including bio- and food residues for adsorptive applications.

Computational Exploration of Functional Nanoscale Carbonaceous Materials

Background: The unique ability of carbon to form a wide variety of allotropic modifications has ushered in a new era in material science. Tuning the properties of these materials by functionalization is a must-have tool for their design customized for a specific practical use. The exponentially growing computational power available to researchers allows for the prediction and thorough understanding of the underlying physicochemical processes responsible for the practical properties of pristine and modified carbons using the methods of quantum chemistry. Method: This review focuses on the computational assessment of the influence of functionalization on the properties of carbons and enabling desired practical properties of the new materials. The first section of each part of this review focuses on graphene with nearly planar units built from sp2- carbons. The second section discusses patterns of sp2-carbons rolled up into curved 3D structures in a variety of ways (fullerenes). The overview of other types of carbonaceous materials, including those with a high abundance of sp3-carbons, including nanodiamonds, can be found in the third section of each manuscript’s part. Conclusion: The computational methods are especially critical for predicting electronic properties of materials such as the bandgap, conductivity, optical and photoelectronic properties, solubility, adsorptivity, the potential for catalysis, sensing, imaging, and biomedical applications. We expect that introduction of defects to carbonaceous materials as a type of their functionalization will be a point of growth in this area of computational research.

The combined effect of carbon fiber and carbon nanotubes on the electrical and self-heating properties of cement composites

This work investigates the electrical and heating performance of conductive cement composites by using carbonaceous materials (carbon fibers (CF) and carbon nanotubes (CNT)) as conductive materials. Various volume fractions of carbonaceous materials were used to indicate the electrical heating performance of the cement composites. Experimental results showed that adding the carbonaceous materials in cement composites reduced the electrical resistance by more than 98% than that of the main cement paste. The percolation threshold of all carbonaceous cement composites was found to be between 0.1 and 0.75 vol%. By applying a potential voltage to the cement composites, different heating temperatures were investigated depending on the type of carbonaceous materials and their volume fractions. The conductive cement composites showed high heating performance exceeded 100°C within a record time when the input voltage is 60 V. At the end of the study, an analysis of electric power consumption was carried out to determine the feasibility of using carbonaceous materials as self-heating components in the suggested conductive cement composites.

Investigation into the influencing factors and adsorption characteristics in the removal of sulfonamide antibiotics by carbonaceous materials

Due to the extensive application of sulfonamide antibiotics for disease control on humans and livestock, the discharge of their residuals has caused serious pollution to the water environment. To mitigate this pollution, various types of carbonaceous materials have been used as adsorbents to remove antibiotics from water. In this study, adsorption characteristics of three sulfonamide antibiotics on four carbonaceous materials under complex conditions have been explored in terms of the cycle of adsorption, desorption, and re-adsorption processes, single and interactive effects of multiple influencing factors, kinetics, isotherms, and thermodynamics. Adsorption isotherms of the main substance (sulfamethoxazole) in the co-adsorption system were also analyzed to illustrate the competitive effects of coexisting substances (sulfamerazine and sulfamethazine) and the degree of competition. Results show that initial concentration, pH, and their interactions had significant effects on the adsorption process. The optimal combination of these factors was the initial concentration of 30 mg/L, pH value of 4.0, temperature of 298 K, and ionic strength of 0–0.1 mol/L. The adsorbed amount of SMX was the highest for four materials under the optimal condition (i.e., 91.51 mg/g for PAC, 258.7 mg/g for W-GAC, 184.7 mg/g for 3M-GAC, and 46.14 mg/g for GP). Adsorbents had great potentials to remove sulfonamide antibiotics after desorption, which is valuable for materials' reusability. In addition, the existence of competitive substances would not change the main substance's exothermic or endothermic properties. These results could help reveal the adsorption, desorption, and re-adsorption mechanisms of various carbonaceous materials under complicated situations and provide reference to identify the regeneration conditions of adsorbents as well as determine the levels of influencing factors to remove sulfonamides antibiotics from water.

Green carbonaceous material‒fibrous silica-titania composite photocatalysts for enhanced degradation of toxic 2-chlorophenol

In this work, fibrous silica-titania (FST) was successfully prepared by the microemulsion method prior to the addition of three types of carbonaceous materials: graphitic-carbon nitride, g-C3N4 (CN), graphene nanoplatelets (GN), and multi-wall carbon nanotubes, MWCNT (CNT), via a solid-state microwave irradiation technique. The catalysts were characterized using XRD, FESEM, TEM, FTIR, UV-Vis DRS, N2 adsorption-desorption, XPS and ESR, while their photoactivity was examined on the degradation of toxic 2-chlorophenol (2-CP). The result demonstrated that the initial reaction rate was in the following order: CNFST (5.1 × 10–3 mM min-1) > GNFST (2.5 × 10–3 mM min-1) > CNTFST (2.3 × 10–3 mM min-1). The best performance was due to the polymeric structure of g-C3N4 with a good dispersion of C and N on the surface FST. This dispersion contributed towards an appropriate quantity of defect sites, as a consequence of the greater interaction between g-C3N4 and the FST support, that led to narrowed of band gap energy (2.98 eV to 2.10 eV). The effect of scavenger and ESR studies confirmed that the photodegradation over CNFST occurred via a Z-scheme mechanism. It is noteworthy that the addition of green carbonaceous materials on the FST markedly enhanced the photodegradation of toxic 2-CP.

Supplementary files for publication"Genesis of two types of carbonaceous material and associated with gold mineralization in the Bumo deposit, Hainan Province, South China"

Supplementary files for publication"Genesis of two types of carbonaceous material and associated with gold mineralization in the Bumo deposit, Hainan Province, South China"

Supplementary files for publication"Genesis of two types of carbonaceous material and associated with gold mineralization in the Bumo deposit, Hainan Province, South China"

Supplementary files for publication"Genesis of two types of carbonaceous material and associated with gold mineralization in the Bumo deposit, Hainan Province, South China"

Effect of char addition on anaerobic digestion of animal by-products: evaluating biogas production and process performance.

The effect of char addition on the digestion of animal by-products was evaluated as a way for enhancing the performance of the process. Two different types of carbonaceous materials were tested as carbon conductive elements to improve biological treatment. One was derived from a torrefaction process intended for increasing the energy density of lignocellulosic biomass, and the other was obtained from a hydrothermal carbonisation process. In this research, batch digestion systems of animal waste samples were evaluated at a volatile solid (VS) ratio of 1:1 inoculum-substrate (where the content of the substrate in the system was 1.69 ± 0.2g). The system reported a baseline methane yield of 380LCH4kg VS-1 which increased on average to 470LCH4kg VS-1 following to the addition of char. The presence of char allowed a faster degradation of the lipid and protein material, reducing inhibitory interactions. The use of Fourier transformed infrared spectroscopy was applied for elucidating the predetermination of the degradation process and bring an insight into the greater degradation potential attained when carbon materials are used for enhancing microbial performance.

The critical role of carbon in marrying silicon and graphite anodes for high‐energy lithium‐ion batteries

AbstractIncreasing the energy density of conventional lithium‐ion batteries (LIBs) is important for satisfying the demands of electric vehicles and advanced electronics. Silicon is considered as one of the most‐promising anodes to replace the traditional graphite anode for the realization of high‐energy LIBs due to its extremely high theoretical capacity, although its severe volume changes during lithiation/delithiation have led to a big challenge for practical application. In contrast, the co‐utilization of Si and graphite has been well recognized as one of the preferred strategies for commercialization in the near future. In this review, we focus on different carbonaceous additives, such as carbon nanotubes, reduced graphene oxide, and pyrolyzed carbon derived from precursors such as pitch, sugars, heteroatom polymers, and so forth, which play an important role in constructing micrometer‐sized hierarchical structures of silicon/graphite/carbon (Si/G/C) composites and tailoring the morphology and surface with good structural stability, good adhesion, high electrical conductivity, high tap density, and good interface chemistry to achieve high capacity and long cycling stability simultaneously. We first discuss the importance and challenge of the co‐utilization of Si and graphite. Then, we carefully review and compare the improved effects of various types of carbonaceous materials and their associated structures on the electrochemical performance of Si/G/C composites. We also review the diverse synthesis techniques and treatment methods, which are also significant factors for optimizing Si/G/C composites. Finally, we provide a pertinent evaluation of these forms of carbon according to their suitability for commercialization. We also make far‐ranging suggestions with regard to the selection of proper carbonaceous materials and the design of Si/G/C composites for further development.

Potentiometric Sensors Based on Molecularly Imprinted Polymers for the Detection of Sarcosine

Cancer is the leading cause of death in economically developed countries and the second leading cause of death in developing countries. Prostate cancer (PCa) is the second most diagnosed cancer and the sixth leading cause of death in men worldwide. PCa incidence is 2 to 5 times higher in developed countries as a result of variations in risk factors and diagnostic practices. PCa new cases represent between 6-14% of all global cancer deaths in 2008. In 2013, malignant tumors were ranked in third place as the cause of death in men (10.5%) in Mexico and the most frequent was PCa (16.3%). PCa mortality increased steadily by 2% per year from 1980 to 2011. The incidence varies due to the practice of prostate-specific antigen (PSA) screening and prostate biopsy. In Latin America, the early detection of PCa is very low and it gets frequently detected in advanced stages. Since the introduction of PSA test in 1986, detection and prevention had been improved, but it is still common to found false positive and false negative results. For PCa detection, it is commonly used ELISA test for PSA screening, digital rectal exam for physical inspection of the prostate and the biopsy to confirm or discard the presence of cancer cells. ELISA test is highly sensitive and specific but also its cost is expensive due to the need for natural specific antibodies, their handling and storage and their low chemical stability. Digital rectal exam (DRE) and biopsy are invasive methods and their main disadvantages are several health risks after the biopsy and the incapacity of PCa detection in areas out of the tumor. Hence, there is a need to develop new technologies with high sensibility and lower response time for the detection of prostate cancer biomarkers during the early stage of the disease. Chemical sensors and biosensors have emerged in recent years as particular interest inside the field of analytical chemistry due to their versatility in clinical assays, drugs detection, food and environmental analysis. An essential part of every sensor is the recognition element, which it gives selectivity towards the analyte in a complex matrix. Biosensors used biological components for recognition such as enzymes, receptors, and antibodies. These allowed a high selectivity but due to their low physical and chemical stability, they cannot be used in rough environments. As an alternative, it can be used biomimetics components, which mimic and selectively bind to a natural molecule. Molecularly imprinted technology is based on the “key-lock” principle, which used a template molecule to create a specific recognition site for it through a polymeric matrix. This molecularly imprinted polymer can be used as a recognition element in chemical sensors for detecting cancer biomarkers. For processing signal, a transducer must be used. Epoxy resins constitute a versatile class characterized by excellent chemical and corrosion resistance, good adhesion to various materials, electrically insulating and easy to fabricate. The addition of powdered fillers like carbonaceous material increases the electrical and heat conductivities of epoxies, providing composite materials that combine a high conductivity. These materials can be used as an all solid-contact electrode and can be used in sensors as a transducer. The present work proposes the construction of selective potentiometric electrodes for the detection of biomarkers related to prostate cancer in early stages of the disease. For that, the use of molecularly imprinted polymers as an element of recognition in a liquid membrane, coupled with a conductive support was investigated. All of this will provide a better response time, limits of detection below concentrations from blood and urine, high selectivity, sensitivity, and reproducibility. Transducers were constructed by using 3 types of carbonaceous materials (graphite, graphene and carbon nanotubes) and epoxy resin. They were characterized by cyclic voltammetry, electrochemical impedance spectroscopy, and four-point probe technique to obtain electrical properties of the materials. A molecularly imprinted polymer was synthesized non-covalent via and analytically characterized. The constructed potentiometric sensor employed an all solid-state electrode for sensing and the effect of pH, selectivity, response time and its potentiometric features were evaluated.

Catalytically Graphitized Nanostructured Carbon Xerogels As High Performance Anode Material for Lithium Ion Battery

Carbon materials are most widely used anode materials for Lithium ion battery since their introduction in 1991. Among various types of carbonaceous materials, graphite is still being used widely as anode material in commercial Lithium ion batteries because of its reasonable capacity and good cyclic efficiency. The problem with long term availability and less purity of macro crystalline natural graphite which is more suitable for battery application led researchers to look into preparation of synthetic graphite, basically prepared by carbonizing various graphitizing carbons like petroleum coke, pitch coke etc.. Various other forms of carbons and their composites have been tested for Li ion intercalation. Though they have higher capacity, their poor cyclability and higher irreversible capacity, higher reduction potential restrict them as commercial Li ion battery anode. Other than carbon materials, Ti, Si and Sn based alloys and oxides have been reported in recent years with 3 to 5 times increase in their intercalation capacity compared to graphite but capacity fade is high due to pulverization. In this presentation, we will present the ways to capitalize the higher capacity of hard (non graphitizing) carbons but at the same time minimizing the irreversible capacity losses and thus maximizing the energy density by catalytic graphitizing them at much lower temperature (< 1800 0C) than as usual graphitization temperature (2800-30000C). Although it is reported that control of internal nanostructure is difficult during catalytic graphitization of various organic precursors, some of the recent studies show that for organic aerogels, one can tune porosity by controlling synthesis and processing conditions during the catalytic graphitization. However although highly porous aerogels shows higher initial capacity due to adsorption of lithium ions inside the pores but also have larger irreversible capacity due to increased overall resistance (impedance) by increased double layer capacitance of the active electrode material. In this work, we shall present preparation of RF xerogel derived graphitic carbon with controlled porosity and thus specific surface area by catalytic graphitization in which metal nanoparticles as additive will be mixed with RF sol. During graphitization, these embedded metal additives react with carbon and forms metal carbide before decomposing to form graphite which will act as nuclei for further graphitization. Intercalation capacity of carbon xerogels have been earlier reported as 145 mAh/g however catalytic graphitization of these xerogels not only enhances it significantly but also increase the electrical conductivity by ordering of graphite layers in disordered carbon xerogels, which are the important characteristics of good electrode material. Thus, these nanoporous graphitic carbon behaves as an excellent anode material because of their minimal double layer capacitance compared to aerogels and good inlayer conductivity because of graphitization.

LiFePO4 quantum-dots composite synthesized by a general microreactor strategy for ultra-high-rate lithium ion batteries

Due to the relatively slow, diffusion-controlled faradaic reaction mechanisms of conventional LiFePO4 (LFP) materials, which is hard to deliver satisfied capacity for high rate applications. In this work, ultrafine LFP quantum dots (LFP-QDs) co-modified by two types of carbonaceous materials - amorphous carbon and graphitized conductive carbon (graphene) have been successfully synthesized through a novel microreactor strategy. Because of the very limited area constructed by the dual-carbon microreactor for the growth of LFP crystal, it's demension was furthest suppressed to a very small level (~ 6.5nm). Such a designed nano-composite possesses a large specific surface area for charge adsorption and abundant active sites for faradaic reactions, as well as ideal kinetic features for both electron and ion transport, and thus exhibits ultra-fast, surface-reaction-controlled lithium storage behavior, mimicking the pseudocapacitive mechanisms for supercapacitor materials, in terms of extraordinary rate capability (78mAhg−1 at 200C) and remarkable cycling stability (~ 99% over 1000 cycles at 20C). On the other side, due to the quasi-2D structure of the synthesized LFP-QDs composite, which can be used as the basic unit to further fabricate free-standing film, aerogel and fiber electrode without the addition of binder and conductive agent for different practical applications. In addition, to deeper understand its electrochemical behavior, a combined experimental and density functional theoretical (DFT) calculation study is also introduced.

Interactions between bacteria and heteroatom-modified nanoporous carbon: The influence of nitrogen and sulfur doping

Heteroatom-doped carbon structures have successfully entered the field of advanced functional materials but their impact on living organisms is still poorly examined. Interactions between typical Gram-negative bacteria Escherichia coli, Gram-positive Bacillus cereus and heteroatom-doped nanoporous carbons are studied in this paper. Four types of carbonaceous materials, that is N-doped, S-doped, S/N-co-doped and undoped carbon gels, are considered. Respirometric measurements, dehydrogenases activity and viability tests were conducted to assess the toxicity of the doped carbons against bacteria. The heteroatom-doped and dopant-free carbon gels do not cause an inhibition of bacterial growth nor a lethal effect. On the contrary, we demonstrate that the doped carbons enhance microbial activity. The adhesion of bacteria to the carbon surface was investigated based on the adsorption studies and biofilm formation. It is demonstrated that the doping of carbons with nitrogen induces surface acidity and hydrophilicity, which in turn significantly enhances the bacteria sorption. Unlike the S-doped or undoped materials, the N-doped carbons are characterized by high bacterial affinity, even when compared to efficient bacteria adsorbents, e.g. active carbon Norit. The results obtained demonstrate that N-containing carbon gels support bacterial proliferation and as such may constitute attractive materials for wastewater treatment technologies as well as bioelectrochemical processes.

Effects of the amendment of biochars and carbon nanotubes on the bioavailability of hexabromocyclododecanes (HBCDs) in soil to ecologically different species of earthworms

Biochar is a promising material used in soil amendment and carbon nanotubes may enter soil due to its increasing application. These carbonaceous materials may change the bioavailability of pollutants in soil. In this concern, 0.5% w/w multi-walled carbon nanotubes (MWCNTs) and 3 corn-straw biochars acquired at different pyrolyzing temperatures were used in soil amendment and their influences on the bioavailability of hexabromocyclododecanes (HBCDs), a brominated flame retardant, to 2 ecologically different earthworm species were studied. The amendment of 4 carbonaceous materials all reduced the bioaccumulation of HBCDs in earthworms by 18.2%–67.3%, which varied depending on the type of carbonaceous materials and the pyrolyzing temperature of biochars. The reduction in HBCDs uptake by Eisenia fetida (an epigeic species) was greater than by Metaphire guillelmi (an anecic species). The 2 earthworm species both showed bioaccumulative selectivity on certain HBCD diastereoisomer and enantiomer in the amended soils, which was similar to that in the control soil. Moreover, Tenax-assisted HBCDs desorption test was carried out for the simulation of their bioavailability. The rapid desorption fraction (Frap), total desorption (15 d), and 24 h desorption all correlated well with the uptake of HBCDs in the earthworms, suggesting that the 24 h-desorption, due to its easy availability, can be a good proxy to predict the bioavailability of HBCDs to earthworms in soil.

Acceleration of Carburization and Melting of Reduced Iron in Iron Ore–Carbon Composite Using Different Types of Carbonaceous Materials

Acceleration of Carburization and Melting of Reduced Iron in Iron Ore–Carbon Composite Using Different Types of Carbonaceous Materials

Influence of minerals on the thermal processing of bamboo with a suite of carbonaceous materials

This study focuses on the impacts of minerals naturally existed in different carbonaceous materials on the thermal processing of their blends with bamboo. Combustion characteristics, such as ignition temperature, peak temperature and burnout temperature, were studied using Thermogravimetric Analysis (TGA) to understand how thermal processing was affected by blending with different types of carbonaceous materials. Kinetic parameters, i.e., activation energy and pre-exponential factors, were determined for both combustion and pyrolysis processes. Synergy was observed in the co-pyrolysis of bamboo and carbonaceous materials. The blending of bamboo was found to have positive influence on ignition and burnout performance of all blends. It was showed that when graphite, activated carbon and coal were blended with bamboo by 50:50wt%, ignition temperature of the blends dropped by 466, 90 and 142°C, respectively and burnout temperature dropped by 82, 39 and 37°C respectively. It was found that K and Na in biomass and Ca in coal acted as catalysts and enhanced the overall co-combustion process and resulted in significant synergistic effect.

Growth of carbonaceous nanomaterials over stainless steel foams. Effect of activation temperature

Some of the problems that occur during the operation of chemical reactors based of structured catalytic substrates, as monoliths, foams, membranes, cloths, fibres and other systems, are related to the preparation of long term stable coatings. Frequently, the deposition of the catalytic layer is carried out by washcoating, requiring this step a cautious attention, especially in the case of complex geometries, like of that of foams or cloths. In the case of the deposition of layers of carbonaceous materials (CNMs), an alternative route, avoiding the washcoating, it is their direct growth by catalytic decomposition light hydrocarbons (also called CCVD), over the surface of the metallic substrate. In this case, if the metallic substrate is of stainless steel, it already contains the catalytic active phases like Fe and Ni.In order to optimize the process of CNMs growth over structured metallic substrates, we are studying the effect of the main operational variables of the ethane decomposition reaction on stainless steel foams. In this contribution we present a study of the influence of the temperature of the activation (oxidation and reduction) stage on the type and morphology of the carbonaceous materials formed. The results obtained allow us to determine the optimal operating conditions to maximize the amount and the selectivity of the process to obtain a given type of CNM.

Effects of carbonaceous materials on microbial bioavailability of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) in sediments

In this study, we investigated the influence of various types of carbonaceous materials (CMs) on the bioavailability of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) to polybrominated diphenyl ether (PBDE)-degrading microorganisms in CM-amended sediments. The microbial debromination ratio of BDE-47 was reduced by 92.8%–98.2% in the 5.0% CM-amended sediment compared with in sediment without CM amendment after 100 d of anaerobic incubation. The concentrations of lower brominated products also decreased when the content of CMs increased from 0.2% to 5.0%. The inhibitory effects of CMs on BDE-47 debromination were CM content- and characteristic-specific. The reciprocals of BDE-47 debromination ratios and lower brominated product concentrations showed positive linear correlations with CM contents in sediments (p<0.01), and the slopes of linear regression fitting generally correlated with specific surface areas (SSAs) of CMs. Desorption of BDE-47 from CMs indicated the declined desorbing fraction of BDE-47 was responsible for the reduction in BDE-47 bioavailability to microorganisms, thus decreasing its debromination in sediments amended with CMs. This study revealed that CM amendment could reduce the PBDE bioavailability to PBDE-degrading microorganisms in sediments, and it is expected to help deepen our understanding of the environmental behaviors and risks of PBDEs.

Role of ingestion route in the perfluoroalkyl substance bioaccumulation by Chironomus plumosus larvae in sediments amended with carbonaceous materials

The role of ingestion route in the bioaccumulation of six types of perfluoroalkyl substances (PFASs) by Chironomus plumosus larvae in sediments amended with four types of carbonaceous materials (CMs) was studied. The results showed that the body burden of PFASs decreased in the presence of CMs at mass ratios of 0.2–2%, regardless of ingestion. PFASs accumulated by the larvae with ingestion exposure were higher than those without ingestion, and the role of ingestion route was altered in the presence of CMs. The contribution of ingestion route to PFAS bioaccumulation was 2.7–31.6% without CMs, and it increased to more than 61.4% in the presence of fullerene at mass ratios of 0.2–2%. The enhancement of the ingestion route contribution caused by CMs is due to the fact that the CMs can be ingested and CM-associated PFASs can be partly desorbed in larvae. The maximum desorption efficiency of perfluorooctanoic acid was 20.8% from fullerene by the larval digestive juice. This study suggests that CM-associated PFASs could be accumulated partly by organisms, and the ecological risk of PFASs might increase in some cases with the presence of CMs. This should be considered when applying CMs in PFAS and other hydrophobic organic compound pollution remediation.