Contamination of soils with persistent organic pollutants (POPs), such as organochlorine pesticide, polybrominated diphenyl ethers, halohydrocarbon, polycyclic aromatic hydrocarbons (PAHs) is of ...increasing concern. Microbial degradation is potential mechanism for the removal of POPs, but it is often restricted by low bioavailability of POPs. Thus, it is important to enhance bioavailability of POPs in soil bioremediation. A series of reviews on bioavailability of POPs has been published in the past few years. However, bioavailability of POPs in relation to soil organic matter, minerals and soil microbes has been little studied. To fully understand POPs bioavailability in soil, research on interactions of POPs with soil components and microbial responses in bioavailability limitation conditions are needed. This review focuses on bioavailability mechanisms of POPs in terms of sorption, transport and microbial adaptation, which is particularly novel. In consideration of the significance of bioavailability, further studies should investigate the influence of various bioremediation strategies on POPs bioavailability.
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•Microbial degradation of persistent organic pollutants (POPs) is limited by their low bioavailability.•Sorption, transport and physiological aspects of POPs bioavailability are reviewed.•Surfactants and compost amendments affect the bioavailability of POPs.•Further researches should focus on the influence of various bioremediation strategies on the bioavailability of POPs.
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•Floating porous g-C3N4 composite (FPCN) was successfully fabricated by a facile one-pot method.•FPCN exhibited a good photocatalytic performance under visible light without any ...stirring.•FPCN showed a good stability and reusability.•Possible degradation pathway of tetracycline and mechanism of the photocatalytic process were proposed.
Powder catalysts are difficult to recycle, which may induce secondary pollution and may limit their practical application. Herein, we successfully synthesized floating porous g-C3N4 (FPCN) using a melamine sponge and urea via a facile one-pot method, which can solve the recycling problem of powder catalysts. The highest elimination efficiency of 5 mg/L tetracycline (TC) reached 70% by 2 g/L FPCN without any stirring under visible light after 4 h. However, the elimination efficiency of 5 mg/L TC by 2 g/L powder g-C3N4 was only 36.9% under the same conditions. The good photocatalytic performance of FPCN is attributed to its 3D interconnected network and enhanced light absorption. The effects of inorganic ions and organic matters on the photocatalytic performance of FPCN were studied. Finally, we proposed a possible mechanism and pathway for degradation of TC.
Previous studies have shown that γδ TFH cells are capable of modulating antibody production in immunized and infected mouse model. In recent studies, human γδ TFH cells are shown to contribute to the ...activation of humoral immunity and promote the maturation of B cells. However, little information is available on their involvement in neuroblastoma (NB) pathogenesis.
In the present study, the frequency of γδ TFH cells in 74 NB patients was significantly higher compared with that in 60 healthy controls. Moreover, most γδ TFH cells in NB patients had a naive phenotype with up-regulation of CD25, CD69, HLA-DR and CD40L and down-regulation of ICOS. Importantly, γδ TFH cells in NB patients produced more IL-4 and IL-10 than those in healthy controls. Furthermore, serum total IgG level was significantly increased in NB patients compared with healthy controls. The expression of CD23 on B cells was up-regulated while CD80 expression was significantly down-regulated in NB patients. Further analysis of B cell compartment showed that the frequency of CD19
CD27
plasma cells was enhanced in NB patients. Spearman's correlation analysis revealed that the frequency of γδ TFH cells was positively correlated to serum total IgG level and CD19
CD27
plasma cells in NB patients, but negatively correlated to CD19
B cells.
We concluded that γδ TFH cells might promote B cell maturation and antibody production in NB patients.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Semiconductor photocatalysis is a promising technology to tackle refractory antibiotics contamination in water. Herein, a facile in situ growth strategy is developed to implant single‐atom cobalt in ...polymeric carbon nitride (pCN) via the bidentate ligand for efficient photocatalytic degradation of oxytetracycline (OTC). The atomic characterizations indicate that single‐atom cobalt is successfully anchored on pCN by covalently forming the CoO bond and CoN bond, which will strengthen the interaction between single‐atom cobalt and pCN. This single‐atom cobalt can efficiently expand optical absorption, increase electron density, facilitate charge separation and transfer, and promote OTC degradation. As the optimal sample, Co(1.28%)pCN presents an outstanding apparent rate constant for OTC degradation (0.038 min−1) under visible light irradiation, which is about 3.7 times than that of the pristine pCN. The electron spin resonance (ESR) tests and reactive species trapping experiments demonstrate that the 1O2, h+, •O2−, and •OH are responsible for OTC degradation. This work develops a new way to construct single‐atom‐modified pCN and provides a green and highly efficient strategy for refractory antibiotics removal.
Single‐atom cobalt is in situ grown on polymeric carbon nitride by the CoO and CoN bidentate ligands, exhibiting superb photocatalytic performance in the degradation of oxytetracycline under visible light irradiation (λ > 420 nm) due to the improved molecular oxygen activation ability induced by the boosted exciton dissociation and accelerated charge transfer.
Soil and sediment contamination has become a critical issue worldwide due to its great harm to the ecological environment and public health. In recent years, many remediation technologies including ...physical, chemical, biological, and combined methods have been proposed and adopted for the purpose of solving the problems of soil and sediment contamination. However, current research on evaluation methods for assessing these remediation technologies is scattered and lacks valid and integrated evaluation methods for assessing the remediation effectiveness. This paper provides a comprehensive review with an environmental perspective on the evaluation methods for assessing the effectiveness of in situ remediation of soil and sediment contaminated with organic pollutants and heavy metals. The review systematically summarizes recent exploration and attempts of the remediation effectiveness assessment based on the content of pollutants, soil and sediment characteristics, and ecological risks. Moreover, limitations and future research needs of the practical assessment are discussed. These limitations are not conducive to the implementation of the abatement and control programs for soil and sediment contamination. Therefore, more attention should be paid to the evaluation methods for assessing the remediation effectiveness while developing new in situ remediation technologies in future research.
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•Methods for in situ remediation of contaminated soil and sediment are outlined.•Recent assessments of the remediation effectiveness are systematically summarized.•Evaluation principles involved in the assessments are discussed.•The limitations and future research needs are suggested.
The adsorbability on the carbonaceous cathode plays an important role in electro-Fenton systems but does not obtain enough attention. In this work, various carbon felts were obtained with different ...adsorption property by using the method of KOH activation at different temperatures to explore the influence of adsorption on the degradation efficiency of tetracycline (TC). The results of morphology characterization, nitrogen adsorption-desorption tests, XPS and FTIR analysis revealed that the surface area of carbon felt was improved, and the oxygen-containing functional groups on the surface were increased via KOH method with significantly enhanced adsorption capacity. In the batch experiment of TC electro-Fenton degradation, the carbon felt with better adsorption capacity tended to get higher degradation and mineralization efficiency. With the KOH activation process, CF-900 (carbon felt at 900 °C for 1 h) exhibited the best TC adsorption property for the removal of TC within 30 min (initial concentration: 80 mg/L). Meanwhile, the constant of reaction rate for TC degradation at the CF-900 is 0.0648 min−1. It is higher than that (0.012 min−1) obtained at the raw carbon felt (∼5 times of enhancement). There are also synergistic effects between adsorption and degradation performance on some other organic pollutants. In addition, the degradation pathway was also studied by the methods of solid-phase extraction and high performance liquid chromatography-mass spectrometry (HPLC). From the obtained results, it is shown that good adsorbability is favorable for degradation in the homogeneous electro-Fenton system.
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•The KOH activation method enhanced the surface chemical adsorption of carbon felt.•The synergistic effect between adsorption and degradation was shown.•Comparison of four different carbon felts in the electro-Fenton process.•The optimal removal capacity was found in the modified carbon felts.•The solid-phase extraction method was used to extract the degradation products.
The presence of exogenous carbonaceous materials (ECMs) in organic contaminated soil is widespread because of their intentional application as carbonaceous amendments (e.g. biochar and activated ...carbon) or unintentional discharge (e.g. carbon nanomaterials). Most research so far has focused on the sorption behaviors of ECMs in soil. However, the impact of ECMs on the bioavailability of organic pollutants (OPs) and their ecological damages remain unclear. This paper presents an overview on how the ECMs affect bioavailability of OPs to different organisms, such as microorganisms, plants and earthworms. This is affected by different biological response and properties of ECMs. Moreover, the possible risks of ECMs on soil biota are also discussed at different level. This review presents a unique insight into risk assessment of ECMs. Further researches should focus on possible change in physicochemical characteristics of ECMs when exposed to the natural environment and the consequent influence on their sorption ability and ecotoxicity outcomes.
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•Exogenous carbonaceous materials and biological response affect the bioavailability of organic pollutants.•ECMs could be co-contaminant and adversely affect soil organisms.•The sorption capacity and ecotoxicity of ECMs could be changed when exposed to the natural environment.
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The advanced oxidation process (AOPs) has caused great concern in recent years. Among them, biochar has been widely studied as a catalyst for advanced oxidation process because of its ...low price and low environmental risk. In this study, a novel ball milling assisted KOH activation biochar (MKBC) was prepared and applied in peroxydisulfate (PDS) activation to degrade tetracycline hydrochloride (TC-H). In comparison with the oxidation (3.48%) by PDS alone and adsorption (36.19%) by MKBC alone, the removal rate of TC-H was increased to 84.15% in the MKBC/PDS system, indicating that MKBC can successfully activate PDS. Besides, the catalytic activity of the MKBC to activate PDS for the degradation of TC-H is 58.33% higher than that of pristine biochar (PBC). In addition, MKBC has outstanding stability that after three repeated experiments, the removal rate of TC-H by the MKBC/PDS system still remains 77.35%. Meanwhile, the mechanism was investigated that the singlet oxygen (1O2) seized the principal position in the degradation of TC-H in the PDS/MKBC system. This study explored a novel, solvent-free and economic method to propose this extraordinary biochar, which provided a new strategy for the future research of biochar.
To develop a metal-free biochar with high and inherent catalytic activity towards refractory and highly toxic contaminants in advanced oxidation processes, it is necessary to explore its reaction ...pathways and responsible catalytic sites. Herein, a metal-free biochar derived from corn cob (CCBC) was prepared and used for reaction pathway analysis during peroxydisulfate (PDS) activation. The pyrolysis temperature played an important role for regulating the biochar structure and properties, and CCBC obtained at 800 °C showed the best adsorption capacity and catalytic activity towards five typical organic pollutants, including 2, 4-dichlorophenol, Tetracycline hydrochloride, Ciprofloxacin, Methyl orange and Rhodamine B, due to its richer pore and defect structure. Further treatment of pharmaceutical wastewater demonstrated the good efficiency and potential of this metal-free catalyst for practical application. Radical (58% contribution) and non-radical (42% contribution) pathways were both found in CCBC/PDS system. More importantly, further redox experiments manifested that the carbon framework (defects, sp2-hybrid carbon, etc.) only made a contribution to the free radical pathway, while the ketone group (CO) of CCBC was proved to be mainly responsible for the non-radical pathway, namely the generation of singlet oxygen (1O2).
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•Porosity and defects facilitate adsorption and catalytic performance.•Radical and non-radical pathways were both found in the system.•C=O and defects on the carbon framework were two key active sites.•Carbon frame only contributed to free radicals and 1O2 was mainly generated by C=O.•CCBC was effective to pharmaceutical wastewater and organics degradation.
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•The remediation efficiency of composting technology depends on its influence on bioavailability of organic pollutants.•Composts have contradictory effect on the bioavailability of ...organic pollutants.•Impact factors of composting technology on bioavailability of organic pollutants are discussed.
Large numbers of organic pollutants (OPs), such as polycyclic aromatic hydrocarbons, pesticides and petroleum, are discharged into soil, posing a huge threat to natural environment. Traditional chemical and physical remediation technologies are either incompetent or expensive, and may cause secondary pollution. The technology of soil composting or use of compost as soil amendment can utilize quantities of active microbes to degrade OPs with the help of available nutrients in the compost matrix. It is highly cost-effective for soil remediation. On the one hand, compost incorporated into contaminated soil is capable of increasing the organic matter content, which improves the soil environment and stimulates the metabolically activity of microbial community. On the other hand, the organic matter in composts would increase the adsorption of OPs and affect their bioavailability, leading to decreased fraction available for microorganism-mediated degradation. Some advanced instrumental analytical approaches developed in recent years may be adopted to expound this process. Therefore, the study on bioavailability of OPs in soil is extremely important for the application of composting technology. This work will discuss the changes of physical and chemical properties of contaminated soils and the bioavailability of OPs by the adsorption of composting matrix. The characteristics of OPs, types and compositions of compost amendments, soil/compost ratio and compost distribution influence the bioavailability of OPs. In addition, the impact of composting factors (composting temperature, co-substrates and exogenous microorganisms) on the removal and bioavailability of OPs is also studied.
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