Efficient destruction of perfluoroalkyl compounds in contaminated waters remains a challenge because of highly stable C–F bonds. In this study, mineralization of perfluorooctanoic acid (PFOA) with ...high concentration (∼30 mg/L) was realized in a needle–plate pulsed discharge reactor integrated with a water jet (NPDW) to which microbubbles (MBs) with different carrier gases (air, N2, and Ar) were introduced to enhance interfacial reactions. MBs effectively enrich dispersed PFOA from a bulk solution to a liquid surface to allow enhancing contact with reactive species and also expanding the plasma discharge area and channels. The PFOA removal efficiency in air and Ar discharge reached 81.5 and 95.3% in 2 h, respectively, with a defluorination ratio of no less than 50%. Energy requirements (EE/O) ranged from 216.49 to 331.95 kWh/m3. Aside from fluoride, PFOA was degraded to a range of short-chain perfluoroalkyl acids and, to a minor extent, at least 20 other fluorinated transformation products. PFOA degradation mechanisms were proposed, including decarboxylation, hydroxylation, hydrogenation reduction, and defluorination reactions. Real water matrices (groundwater, tap water, wastewater effluent, and surface water) showed moderate impact on treatment outcomes, demonstrating the robustness of the treatment process. The study demonstrated an environmentally friendly nonthermal plasma technology for effective PFOA degradation.
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IJS, KILJ, NUK, PNG, UL, UM
Traditional seed pretreatment methods cause secondary pollution for the application of various chemicals. This study investigated the effect of dielectric barrier discharge (DBD) cold plasma on ...seedling growth. Effects of plasma-activated tap water (PATW) and plasma-activated seeds (PAS) were compared for germination rates, seedling height, dry weight, and chlorophyll content. Results show that compared with controls these growth parameters were all increased by more than 50%. The yields and contributions of hydrogen peroxide, nitrate, nitrite, and ammonium were quantified. Hydrogen peroxide and nitrate have an important role in seedling growth. By etching, the seed epidermis free radicals can reduce the apparent contact angle and increase the water absorption of the seeds. In addition to the low cost of PATW and PAS compared with commercial fertilizers, DBD does not involve any chemical addition. Thus, both PATW and PAS can be an alternative for improvement of agricultural production.
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IJS, KILJ, NUK, PNG, UL, UM, UPUK
Inorganic lead is one of the most common causes of environmental metal poisonings, and its adverse effects on multiple body systems are of great concern. The brain, along with the kidneys, are ...critically susceptible to lead toxicity for their hosting of high affinity lead binding proteins, and very sensitive physiology. Prolonged low-lead exposure frequently remains unrecognized, causes subtle changes in these organ systems, and manifests later at an irreversible stage. With the repeated documentation of “no safe blood lead level”, the pernicious effects of lead at any measurable concentration need to be emphasized. In this review, we surveyed articles on chronic low-level lead exposures with a blood lead concentrations <10μg/dL and the development of neurobehavioral or renal disorders. The negative impacts of lead on both nervous and renal systems were obvious at a blood lead concentration of 2μg/dL, with the absence of any detectable threshold. The deleterious effect of lead on two different organ systems at such low concentrations drew our attention to the various extracellular and intracellular events that might be affected by minimal concentration of body lead, especially blood lead. Is there a true common ground between low-level lead toxicity in both the nervous system and the kidney?
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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•Soil depth directly affects dielectric barrier discharge plasma (DBD) processing capacity.•Alkyl radicals improved diesel fuel degradation efficiency during DBD ...treatment.•Degradation pathway of diesel fuel were proposed.•Experimental results proved the feasibility of heavily diesel-fuel-polluted soil remediation using DBD.
Diesel-fuel-polluted soil poses a risk to both the environment and human health. This study assessed the feasibility and efficiency of dielectric barrier discharges (DBD) for the degradation of diesel fuel in soil. At 180 W input power, 3 mm soil depth, initial concentration of 10,000 mg/kg, soil pH of 7.1, and 2% moisture, the degradation efficiency of diesel fuel reached 74% within 40 min of the treatment. The diesel fuel removal efficiency decreased significantly at a soil depth of >3 mm, and increased soil moisture impaired the process. With a high initial diesel fuel concentration, the removal efficiency was high due to the action of alkyl radicals. The most effectively removed hydrocarbons had <17 carbons, and by-products were mainly esters, anhydrides, and long-chain alkanes. The remediation efficiency of the actual petroleum-polluted soil from the Heilongjiang province of China was tested using DBD. The removal efficiency for saturated hydrocarbons was 71% at a power of 180 W for 40 min. Thus, DBD can be used as an efficient method for diesel-fuel-polluted soil remediation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The applications of photocatalytic pollutant degradation have remained limited due to the low efficiency of solar energy utilization. In this study, a photothermal catalyst consisting of reduced ...graphene oxide @ black TiO2 (RGO@BT) nanofluid with effective full-spectrum (from ultraviolet to infrared light) absorption was synthesized by a typical two-step method of high temperature calcination and hydrothermal method. Moreover, the photothermal catalytic performance of the RGO@BT nanofluid on tetracycline was verified. Compared with individual processes (i.e, photocatalysis and thermocatalysis), the photothermal catalytic process significantly enhanced tetracycline degradation under simulated global standard spectrum sunlight (AM 1.5G, 1000 W m−2). The maximum photothermal conversion efficiency reached 91.8%, which resulted in 94.7% tetracycline degradation (40 mg L−1) after 120 min of treatment with 200 mg L−1 RGO@BT nanofluid. Holes, OH, and O2− were found to be the main active species during the photothermal catalytic process. Moreover, heat was spontaneously converted from light energy without the use of any external energy source. The elevated system temperature facilitated the tetracycline degradation based on the Arrhenius behavior. These findings provide insights into the improvement of photocatalytic efficiency in organic contaminant degradation via solar energy-efficient photothermal conversion materials.
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•A RGO@BT nanofluid with effective full-spectrum absorption was prepared.•The RGO@BT nanofluid showed excellent photothermal conversion and catalytic ability.•Holes, OH and O2− were found to be the main active species.•Heat was spontaneously converted from light energy without any external energy.•The elevated temperature raised tetracycline degradation based on Arrhenius behavior.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Long chain PFAS can be effectively removed in the falling film DBD system due to their high reactivity and interfacial adsorption.•The insertion of ether oxygen enhanced the rate constants of PFAS ...removal but hindered the defluorination process.•PFSAs demonstrated higher defluorination efficiency due to their susceptibility to electron attack.•Synergistic effects of electrons, OH• and NO2• are pivotal to PFAS decomposition.
Non-thermal plasma emerges as a promising technology for per- and polyfluoroalkyl substances (PFAS) decomposition due to its notable efficacy and environmentally friendly characteristics. In this study, we demonstrated the efficacy of a falling film dielectric barrier discharge (DBD) system for the removal of 10 PFAS, including perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkyl sulfonic acids (PFSAs) and hexafluoropropylene oxide (HFPO) oligomer acids. Results showed that compounds with fluoroalkyl chain length>4 were effectively decomposed within 100 min, with long-chain PFAS demonstrating more pronounced removal performance than their short-chain analogues. The superior removal but low defluorination observed in HFPO oligomer acids could be ascribed to their ether-based structural features. The integration of experimental results with density functional theory (DFT) calculations revealed that the synergistic effects of various reactive species are pivotal to their efficient decomposition, with electrons, OH•, and NO2• playing essential roles. In contrast, the degradation of PFSAs was more dependent on electron attack than that of PFCAs and HFPO oligomer acids. Significantly, the most crucial degradation pathway for HFPO oligomer acids was the cleavage of ether CO, whether through radical or electron attack. Furthermore, the demonstrated effective removal in various water matrices showed the potential of the plasma system for removing PFAS in complex aquatic environments. This study provided mechanistic insights into PFAS degradation behavior in plasma processes, and it underscored the vital influence of molecular structures on degradability, thereby contributing to the further development and regulation of plasma-based technologies for treating PFAS in water.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•PCD plasma was utilized for PFOA removal in soil.•High-energy electrons are confirmed as the dominant active agent for PFOA degradation during PCD plasma treatment.•PFOA degradation ...mechanism was explored based on LC–MS, FT-IR and density functional theory analysis.•Germination and dry weight of lettuce were improved after plasma treatment.
Perfluorooctanoic acid (PFOA) from contaminated soil accumulates in higher organisms, and causes health risks to humans. In this research, 71 % of the PFOA was degraded, of which 51 % was decomposed into short chain by-products, 19 % mineralized, and 1 % volatilized with 30 kV of voltage, 50 Hz of discharge frequency, 1 % of soil moisture, 300 ppm of PFOA concentration and 6.3 of soil pH using pulsed positive discharge plasma. From a series of experiments, electrons were identified as the dominant active means of PFOA degradation. The decomposition by-products were analyzed by LC–MS. The results indicated that PFOA was decomposed into small by-products including perfluoroheptanoic acid (PFHpA), perfluorohexanoic acid (PFHxA), perfluoropentanoic acid (PFPeA), perfluorobutyric acid (PFBA), pentafluoropropionic acid (PFPrA) and trifluoroacetic acid (TFA). Moreover, in plasma treated soil, the concentration of ammonia nitrogen increased from less than 10 ppm–462 ppm, and the average dry weight of lettuce was 1.6 mg higher than that in natural soil. Additionally, Planctomycetes and Nitrospirae increased after treatment, indicating that plasma technology promotes the process of nitrogen cycle. Thus, PFOA polluted soil could be remediated using this pulse corona plasma technology, and simultaneously improve the fertility of soil without chemical injections.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Phthalate ester plasticizers are used to improve the plasticity and strength of plastics. One of the most widely used and studied, di-2-ethylhexyl phthalate (DEHP), has been labeled as an endocrine ...disruptor. The major and toxic metabolic derivative of DEHP, mono-2-ethylhexyl phthalate (MEHP), is capable of interfering with mitochondrial function, but its mechanism of action on mitophagy remains elusive. Here, we report that MEHP exacerbates cytotoxicity by amplifying the PINK1-Parkin-mediated mitophagy pathway. First, MEHP exacerbated mitochondrial damage induced by low-dose CCCP via increased reactive oxygen species (ROS) production, decreased mitochondrial membrane potential (MMP), and enhanced fragmentation in mitochondria. Second, co-exposure to MEHP and CCCP (“MEHP-CCCP”) induced robust mitophagy. Mechanistically, MEHP-CCCP stabilized PINK1, increased the level of phosphorylated ubiquitin (pSer 65-Ub), and led to Parkin mitochondrial translocation and activation. Third, MEHP-CCCP synergistically caused more cell death, while inhibition of mitophagy, either through chemical or gene silencing, reduced cell death. Finally and importantly, co-treatment with N-acetyl cysteine (NAC) completely counteracted the effects of MEHP-CCCP, suggesting that mitochondrial ROS played a vital role in this process. Our results link mitophagy and MEHP cytotoxicity, providing an insight into the potential roles of endocrine disrupting chemicals (EDCs) in human diseases such as Parkinson's disease.
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•Mono-2-ethylhexyl phthalate (MEHP) exacerbates mitochondrial damage induced by low-dose CCCP.•Co-exposure to MEHP and CCCP (MEHP-CCCP) induces robust mitophagy in a PINK1-Parkin-dependent pathway.•Mitophagy promotes MEHP-CCCP-induced cell death.•ROS mediate MEHP-CCCP-induced mitophagy and cytotoxicity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•DBD-biochar technology was proved to remediate atrazine contaminated soil.•The germination and dry weight of lettuce improved after DBD-biochar treatment.•DBD-biochar technology can ...stabilize soil pH and increase microbial abundance.•The results proved the feasibility of soil reuse after DBD-biochar remediation.
Dielectric barrier discharge (DBD)-biochar sequential batch experimental technology was employed to degrade atrazine (ATZ) in soil. The hydrophilicity, particle size and instability of soil particles increased after DBD treatment, which contributed to the exposure of residual ATZ in the soil. Meanwhile, the subsequent introduction of biochar compensated for the shortcomings of sole DBD treatment (e.g. increased soil sparseness and pH, enhanced the living environment of microorganisms). The ATZ removal efficiency in air discharge reached 66.1 % after 10 min of DBD treatment and 30 min of biochar adsorption, and the energy yield was 4.2 times higher than that of sole DBD treatment. The functional active species in ATZ degradation were confirmed to be oxygen-containing reactive species. ATZ degradation mechanisms were proposed, including dealkylation, dechloro-hydroxylation, alkylic-hydroxylation, alkylic-oxidation, olefinization and deamino-hydroxylation reactions. Hence, the study demonstrated an environmentally friendly technology for effective ATZ degradation while improving the fertility of soil with no chemical injections.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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