Assessment of potential ecological risk for polycyclic aromatic hydrocarbons in urban soils with high level of atmospheric particulate matter concentration.

Polycyclic aromatic hydrocarbons (PAHs) are known to be representative carcinogenic environmental pollutants with high toxicity. However, information on the potential ecological and environmental risks of PAH contamination in soil remains scarce. Thus, this study was evaluated the potential ecological risks of PAHs in soils of five Korean areas (Gunsan (GS), Gwangju, Yeongnam, Busan, and Gangwon) using organic carbon (OC)-normalized analysis, mean effect range-median quotient (M-ERM-Q), toxic equivalent quantity (TEQ) analysis, and risk quotient (RQ) derived by the species sensitivity distribution model. In this study, atmospheric particulate matter has a significant effect on soil pollution in GS through the presence of hopanes and the similar pattern of PAHs in soil and atmospheric PAHs. From analysis of source identification, combustion sources in soils of GS were important PAH sources. For PAHs in soils of GS, the OC-normalized analysis, M-ERM-Q, and TEQ analysis have 26.78 × 105 ng/g-OC, 0.218, and 49.72, respectively. Therefore, the potential ecological risk assessment results showed that GS had moderate-high ecological risk and moderate-high carcinogenic risk, whereas the other regions had low ecological risk and low-moderate carcinogenic risk. The risk level (M-ERM-Q) of PAH contamination in GS was similar to that in Changchun and Xiangxi Bay in China. The Port Harcourt City in Nigeria for PAH has the highest risk (M-ERM-Q = 4.02 and TEQ = 7923). Especially, compared to China (RQPhe =0.025 and 0.05), and Nigeria (0.059), phenanthrene showed the highest ecological risk in Korea (0.001-0.18). Korea should focus on controlling the release of PAHs originating from the PM in GS.

Oral exposure to phenanthrene during gestation disorders endocrine and spermatogenesis in F1 adult male mice.

Phenanthrene (Phe), a typical low-molecular-weight polycyclic aromatic hydrocarbon (PAH) of three benzene rings, is one of the most abundant PAHs detected in daily diets. Pregnant women and infants are at great risk of Phe exposure. In the present study, Phe was administered to pregnant mice at a dose of 0, 60, or 600 µg/kg body weight six times, and the F1 male mice showed significant reproductive disorders: the testicular weight and testis somatic index were significantly reduced; the levels of serum testosterone, GnRH and SHBG were increased, while the FSH levels were reduced; histological analysis showed that the amount of Sertoli cells and primary spermatocytes in seminiferous tubules was increased, while the amount of secondary spermatocytes and spermatids were decreased in Phe groups. The protein levels of PCNA and androgen receptor were reduced. Differently expressed genes in the testis screened by RNA sequence were enriched in antioxidant capacity, reproduction et al.. Further biochemical tests confirmed that the antioxidant capacity in the F1 testis was significantly inhibited by treatment with Phe during pregnancy. Those results suggested that gestational Phe exposure disordered hypothalamic-pituitary-gonadal (HPG) hormones on the one hand, and on the other hand reduced testicular antioxidant capacity and further arrested cell cycle in F1 adult male mice, which co-caused the inhibition of spermatogenesis.

A new phenanthrene with a spirolactone ring from Dendrobium ochreatum.

Dendroochreatene (1), a new phenanthrene derivative with a spirolactone ring, was isolated from the whole Dendrobium ochreatum plant together with 11 known compounds (2-12). The structure of the new compound was elucidated spectroscopically and phenolic compounds were firstly reported from D. ochreatum. Moscatilin (4), major compound isolated from D. ochreatum, was found to be cytotoxic toward H460 lung-cancer cells, with an IC50 value of 147.3 ± 0.9 µM, while loddigesiinol C (7), C-α-methoxy derivative was inactive.

Mechanistic insight into the effects of interaction between biochar and soil with different properties on phenanthrene sorption.

Soil composition varies considerably in nature, so it is vital to investigate the mechanism of the effect of various soil parameters on biochar sorption capacity. In this study, two biochars (W4 and W7) were derived from wheat straw at temperatures of 400 and 700 °C and were incubated with three different soils. Changes in biochar surface features by aging in the soils and the consequent impact on phenanthrene sorption were examined. The results showed that the effect of adding biochar on phenanthrene sorption capacity (Koc) varied by soil. When biochar was freshly mixed with soil, the Koc value in soil with higher clay content was more dramatically altered by biochar, which is due to clay particles adhering to the biochar surface. Moreover, the Koc value was significantly decreased by the addition of W4 but increased by the addition of W7 in general. After aging, most of the Koc value decreased. The greatest decrease in Koc value was observed in biochar and soil composed with the highest clay content for W4 (24-63%), as well as soil composed with the highest organic matter content for W7 (46-64%). This is because the surface polarity and micropores of biochar dropped the most rapidly in these mixes, resulting in a significant decrease in hydrophobic and pore-filling properties. The results revealed that the impact of biochar-soil interactions on phenanthrene sorption is related to not only biochar properties but also soil clay particles, soil organic matter content and pH. The findings of the study can be utilized to assess the efficacy of biochar application in soil remediation for various features.

Host-Guest Cocrystallization of Phenanthrene[2]arene Macrocycles Facilitating Structure Determination of Liquid Organic Molecules.

Single-crystal X-ray diffraction analysis has emerged as the most reliable method for determining the structures of organic molecules. However, numerous analytes, such as liquid organic molecules, pose challenges in crystallization, making their structures directly elusive via X-ray crystallography methods. Herein, we introduced the rapid cocrystallization of a macrocycle named phenanthrene[2]arene (PTA, host) with 15 liquid organic molecules (guests). The guest liquid organic molecules were successively cocrystallized with the aid of the PTA host. Moreover, the chemical structures of the liquid organic molecules could be determined through single-crystal X-ray diffraction analysis. PTA exhibited high adaptivity and was capable of encapsulating liquid organic molecules without forming covalent bonds or strong directional interactions. The results revealed that the adaptive crystals of PTA exhibited excellent cocrystallization capacity. Weak noncovalent interactions between the host and guest molecules were crucial for organizing the guests in an ordered pattern.

Recent allopolyploidy alters Spartina microRNA expression in response to xenobiotic-induced stress.

Environmental contamination by xenobiotics represents a major threat for natural ecosystems and public health. In response, xenobiotic detoxification is a fundamental trait of organisms for developmental plasticity and stress tolerance, but the underlying molecular mechanisms remain poorly understood in plants. To decipher this process, we explored the consequences of allopolyploidy on xenobiotic tolerance in the genus Spartina Schreb. Specifically, we focused on microRNAs (miRNAs) owing to their central function in the regulation of gene expression patterns, including responses to stress. Small RNA-Seq was conducted on the parents S. alterniflora and S. maritima, their F1 hybrid S. x townsendii and the allopolyploid S. anglica under phenanthrene-induced stress (phe), a model Polycyclic Aromatic Hydrocarbon (PAH) compound. Differentially expressed miRNAs in response to phe were specifically identified within species. In complement, the respective impacts of hybridization and genome doubling were detected, through changes in miRNA expression patterns between S. x townsendii, S. anglica and the parents. The results support the impact of allopolyploidy in miRNA-guided regulation of plant response to phe. In total, we identified 17 phe-responsive miRNAs in Spartina among up-regulated MIR156 and down-regulated MIR159. We also describe novel phe-responsive miRNAs as putative Spartina-specific gene expression regulators in response to stress. Functional validation using Arabidopsis (L.) Heynh. T-DNA lines inserted in homologous MIR genes was performed, and the divergence of phe-responsive miRNA regulatory networks between Arabidopsis and Spartina was discussed.

Influence of Soil Moisture on Bioaccumulation, Growth, and Recruitment of Folsomia candida Exposed to Phenanthrene-Polluted Soil.

Climate change has resulted in an increased occurrence of summer droughts in large parts of the world. Low soil moisture has marked impacts on the physiology of soil invertebrates and lowers degradation rates of organic contaminants in soil. Polycyclic aromatic hydrocarbons (PAHs) are hydrophobic contaminants that readily accumulate in the lipids of soil organisms. Here, we exposed springtails (Collembola, small soil living arthropods) to phenanthrene (a common PAH) in combination with a range of soil water contents to investigate the combined effects of these factors on the bioaccumulation, survival, recruitment, and body growth in a full factorial experiment. The results showed that phenanthrene up to 60 mg/kg dry soil had moderate effects on survival (<20%), whereas dry soil (4% soil water content) caused approximately 60% mortality. The bioaccumulation of phenanthrene increased almost 3-fold when soil water content decreased from 22 to 4%. We observed a joint effect of low soil water content and phenanthrene on recruitment, suggesting a synergistic interaction. The recruitment EC50 values of phenanthrene decreased from approximately 40 mg/kg dry soil at 22% soil water content to approximately 10 mg/kg dry soil at 12% soil water content. Our results show that the effects of phenanthrene are more pronounced in dry soil partly because bioaccumulation is enhanced when soils become dry.

Development of a Sensitive and Selective Method for the Determination of some Selected Aldehydes Based on Fluorescence Quenching.

Phenanthrene fluorescence quenching in anionic micellar system of sodium dodecyl sulphate (SDS) was explored for the development of a sensitive and selective method for a group of selected aldehydes (2,6-dichlorobenzaldehyde, 4-(dimethylamino)benzaldehyde, 4-aminobenzaldehyde, 4-nitrobenzaldehyde, 2-chlorobenzaldehyde, benzaldehyde and 2-methoxybenzaldehyde). Experiments were performed in 0.02 mol L- 1 SDS. All the studied aldehydes quenched the fluorescence intensity of the probe (phenanthrene). Stern-Volmer equation was useful in explaining the phenanthrene quenching by the studied aldehydes. Stern-Volmer constants ([Formula: see text]) were obtained as a result of using the Stern-Volmer equation that gives the information in respect of sensitivity of the method for the studied aldehydes. Greater the [Formula: see text] higher will be the sensitivity and vice versa. [Formula: see text], detection limit (DL) and quantification limit (QL) were observed in the order 2,6-dichlorobenzaldehyde > 4-dimethylaminobenzaldehyde > 4-aminobenzaldehyde > 4-nitrobenzaldehyde > 2-chlorobenzaldehyde > benzaldehyde > 2-methoxybenzaldehyde. Phenanthrene fluorescence quenching by the studied aldehydes is useful for their determination in environmental samples.

Autochthonous bioaugmentation accelerates phenanthrene degradation in acclimated soil.

Bioaugmentation helps to obtain a microbiome capable of remediating polycyclic aromatic hydrocarbons (PAHs). In this study, acclimation of microorganisms to soil supplemented with phenanthrene (PHE) led to enrichment with PAH-degraders, including those in Actinobacteriota and in the genera Streptomyces, Rhodococcus, Nocardioides, Sphingomonas, and Mycobacterium. Aqueous (28 °C, pH 6.5) and soil cultures inoculated with PHE-acclimated soil showed a high PHE (ca. 50 mg L-1) degradation efficiency. The PHE degradation kinetics in aqueous and soil incubations fitted to the Gompertz equation and the first-order kinetic equation, respectively. Indigenous microorganisms adapted to PHE in their environment, and this increased their capacity to degrade PHE. The effect of co-contaminants and pathway intermediates on PHE degradation showed that the degradation of PHE improved in the presence of diesel while being hindered by lubricant oil, catechol, salicylic and phthalic acid. Our findings provide theoretical and practical support for bioremediationof PAHs in the environment.

G-C3N4-Ag composite mediated photocatalytic degradation of phenanthrene - A remedy for environmental pollution.

In recent years, g-C3N4-Ag nanocomposite synthesis has gained considerable attention for its potential to treat polycyclic aromatic hydrocarbons (PAHs) and to act against bacteria and fungi. In this study, we present a novel approach to the synthesis of g-C3N4-Ag nanocomposite and evaluate its efficiency in both PAH removal and antimicrobial activity. The synthesis process involved the preparation of g-C3N4 by thermal polycondensation of melamine. The factors that affect the adsorption process of PAHs, like time, pH, irradiation type, and adsorbent dosage, were also evaluated. Isotherm models like Langmuir and Freundlich determined the adsorption capability of g-C3N4-Ag. In simulated models, phenanthrene was degraded to a maximum of 85% at lower concentrations of catalyst. The adsorption profile of phenanthrene obeys the pseudo-second-order and Freundlich isotherms pattern. The g-C3N4-Ag nanocomposite also exhibited antimicrobial activity against bacteria (Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae) and fungi (Candida albicans). The present study is the first report stating the dual application of g-C3N4-Ag nanocomposite in reducing the concentration of PAH and killing bacterial and fungal pathogens. The higher adsorption capability proclaimed by g-C3N4-Ag nanocomposite shows the fabricated nanomaterial with great potential to remediate organic pollutants from the ecosystem.

Anaerobic biodegradation of phenanthrene and pyrene by sulfate-reducing cultures enriched from contaminated freshwater lake sediments.

Our current understanding of the susceptibility of hazardous polycyclic aromatic hydrocarbons (PAHs) to anaerobic microbial degradation is very limited. In the present study, we obtained phenanthrene- and pyrene-degrading strictly anaerobic sulfate-reducing enrichments using contaminated freshwater lake sediments as the source material. The highly enriched phenanthrene-degrading culture, MMKS23, was dominated (98%) by a sulfate-reducing bacterium belonging to the genus Desulfovibrio. While Desulfovibrio sp. was also predominant (79%) in the pyrene-degrading enrichment culture, MMKS44, an anoxygenic purple non-sulfur bacterium, Rhodopseudomonas sp., constituted a significant fraction (18%) of the total microbial community. Phenanthrene or pyrene biodegradation by the enrichment cultures was coupled with sulfate reduction, as evident from near stoichiometric consumption of sulfate and accumulation of sulfide. Also, there was almost complete inhibition of substrate degradation in the presence of an inhibitor of sulfate reduction, i.e., 20 mM MoO42-, in the culture medium. After 180 days of incubation, about 79.40 µM phenanthrene was degraded in the MMKS23 culture, resulting in the consumption of 806.80 µM sulfate and accumulation of 625.80 µM sulfide. Anaerobic pyrene biodegradation by the MMKS44 culture was relatively slow. About 22.30 µM of the substrate was degraded after 180 days resulting in the depletion of 239 µM sulfate and accumulation of 196.90 µM sulfide. Biodegradation of phenanthrene by the enrichment yielded a metabolite, phenanthrene-2-carboxylic acid, suggesting that carboxylation could be a widespread initial step of phenanthrene activation under sulfate-reducing conditions. Overall, this novel study demonstrates the ability of sulfate-reducing bacteria (SRB), dwelling in contaminated freshwater sediments to anaerobically biodegrade three-ringed phenanthrene and highly recalcitrant four-ringed pyrene. Our findings suggest that SRB could play a crucial role in the natural attenuation of PAHs in anoxic freshwater sediments.

Cometabolic degradation of pyrene with phenanthrene as substrate: assisted by halophilic Pseudomonas stutzeri DJP1.

At present, cometabolic degradation is an extensive method for the biological removal of high molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) in the marine environment. However, due to the refractory to degradation and high toxicity, there are few studies on pyrene (PYR) cometabolic degradation with phenanthrene (PHE) as substrate. In this study, a Pseudomonas stutzeri DJP1 strain isolated from sediments was used in the cometabolic system of PHE and PYR. The biomass and the activity of key enzymes such as dehydrogenase and catechol 12 dioxygenase of strain were improved, but the enhancement of biotoxicity resulted in the inhibition of cometabolism simultaneously. Seven metabolites were identified respectively in PYR, PHE degradation cultures. It was speculated that the cometabolism of PHE and PYR had a common phthalic acid pathway, and the degradation pathway of PHE was included in the downstream pathway of PYR. The functional genes such as PhdF, NidD and CatA involved in DJP1 degradation were revealed by Genome analysis. This study provides a reference for the biodegradation of PYR and PHE in real marine environment.

Metaproteomic and gene expression analysis of interspecies interactions in a PAH-degrading synthetic microbial consortium constructed with the key microbes of a natural consortium.

Polycyclic Aromatic Hydrocarbons (PAHs) impose adverse effects on the environment and human life. The use of synthetic microbial consortia is promising in bioremediation of contaminated sites with these pollutants. However, the design of consortia taking advantage of natural interactions has been poorly explored. In this study, a dual synthetic bacterial consortium (DSC_AB) was constructed with two key members (Sphingobium sp. AM and Burkholderia sp. Bk), of a natural PAH degrading consortium. DSC_AB showed significantly enhanced degradation of PAHs and toxic intermediary metabolites relative to the axenic cultures, indicating the existence of synergistic relationships. Metaproteomic and gene-expression analyses were applied to obtain a view of bacterial performance during phenanthrene removal. Overexpression of the Bk genes, naph, biph, tol and sal and the AM gene, ahdB, in DSC_AB relative to axenic cultures, demonstrated that both strains are actively participating in degradation, which gave evidence of cross-feeding. Several proteins related to stress response were under-expressed in DSC_AB relative to axenic cultures, indicating that the division of labour reduces cellular stress, increasing the efficiency of degradation. This is the one of the first works revealing bacterial relationships during PAH removal in a synthetic consortium applying an omics approach. Our findings could be used to develop criteria for evaluating the potential effectiveness of synthetic bacterial consortia in bioremediation.

Evaluation of aerobic biodegradation of phenanthrene using Pseudomonas turukhanskensis: an optimized study.

The ability of Pseudomonas turukhanskensis GEEL-01 to degrade the phenanthrene (PHE) was optimized by response surface methodology (RSM). Three factors as independent variables (including temperature, pH, and inoculum) were studied at 600 mg/L PHE where the highest growth of P. turukhanskensis GEEL-01 was observed. The optimum operating conditions were evaluated through the fit summary analysis, model summary statistics, fit statistics, ANOVA analysis, and model graphs. The degradation of PHE was monitored by high-performance liquid chromatography (HPLC) and the metabolites were identified by gas chromatography-mass spectrometry (GC-MS). The results showed that the correlation among independent variables with experimental and predicted responses was significant (p < 0.0001). The optimal temperature, pH, and inoculum were 30 ℃, 8, and 6 mL respectively. The HPLC peaks exhibited a reduction in PHE concentration from 600 mg/L to 4.97 mg/L with 99% degradation efficiency. The GC-MS peaks indicated that the major end products of PHE degradation were 1-Hydroxy-2-naphthoic acid, salicylic acid, phthalic acid, and catechol. This study demonstrated that the optimized parameters by RSM for P. turukhanskensis GEEL-01 could degrade PHE by phthalic and salicylic acid pathways.

The hepatoprotective effects of Herbt Tea Essences on phenanthrene-induced liver damage in mice.

Phenanthrene (Phe), one of the most frequently occurring pollutants in nature, can cause substantial damage to the human liver. Herbt Tea Essences (HTE), a kind of black tea extract with strong anti-inflammatory activity, can protect humans against disease. Currently, whether HTE can protect the liver from Phe-induced hepatotoxicity remains unclear. Herein, we explore the protective effects of HTE against Phe-induced hepatotoxicity. Our results showed that Phe exposure could significantly induce liver damage and increase serum hepatic enzyme levels in mice. HTE could prevent liver damage and recover the expression levels of inflammatory factors. Furthermore, we found that HTE suppressed the excessive activation of the nuclear transcription factor kappa-B and transforming growth factor-ß/SMAD signaling pathways to alleviate Phe-induced liver inflammation and fibrosis. Overall, our data showed that HTE treatment could be a new preventive means for Phe-induced liver disease.

Phytoremediation of PAH compounds by microbial communities in sodic soil.

The PAH degrading microbial consortium was collected from sodic soil of the nursery of Guru Jambheshwar University of Science and Technology, Hisar, Haryana (India). And the soil was artificially amended with phenanthrene and naphthalene to isolate the PAHs degrading microbial consortium. The diversity of microbial consortium was analyzed using the NGS (Next Generation Sequencing) based metagenomic approach. The result of diversity analysis showed species Tepidanaerobacter syntrophicus, Sphingomonas oliophenolica, Arthrobacter psychrochitinipnius, Bifidobacterium bombi, Nocardiodies islandensis, Rhodovibrio sodomensis, Thiorhodococus pfennigii, Aeromicrobium ponti, Steroidobacter dentrificans, Actinomaduria maheshkhaliensis, Dactylosporangium maewongense, Pelotomaculum isophthalicicum, and Nocardioides islandensis were present in the consortium. Moreover, Sphingomonas, Arthrobacter, Sphingobium, Azospirillium, Thirohodococcus, and Pelotomaculum were the prominent pollutant degrader genera in the microbial consortium. Since the bioremediation of these pollutants occurs with a significant reduction in toxicity, the study's perspective is to use this type of consortium for bioremediation of specifically contaminated soil.

The present work's novelty was to find the helpful microbial consortium for the bioremediation of toxic compounds such as naphthalene and phenanthrene. In this study, the degradation of such compounds was done by the various communities of genera like Bifidobacterium, Conexibacter, Sterodobacter, Rhodovibrio, Arthrobacter, Actinomadura, and Euzebya, which are rarely described in the earlier researches. Therefore, this study will enhance the quality of future research.

1,5,6-Trimethoxy-2,7-dihydroxyphenanthrene from Dendrobium officinale Exhibited Antitumor Activities for HeLa Cells.

Natural products are irreplaceable reservoirs for cancer treatments. In this study, 12 phenanthrene compounds were extracted and isolated from Dendrobium officinale. Each chemical structure was identified using comprehensive NMR analysis. All compounds were evaluated for their cytotoxic activities against five tumor cell lines, i.e., HeLa, MCF-7, SK-N-AS, Capan-2 and Hep G2. Compound 5, 1,5,6-trimethoxy-2,7-dihydroxyphenanthrene, displayed the most significant cytotoxic effect against HeLa and Hep G2 cells, with an IC50 of 0.42 and 0.20 µM. For Hela cells, further experiments demonstrated that compound 5 could obviously inhibit cell migration, block cell cycle in the G0/G1 phase and induce apoptosis. Expression measurements for p53 indicated that knock down of p53 by siRNA could mitigate the apoptosis induced by compound 5. Therefore, the compound 5 is a potential candidate drug for HeLa cells in cervical cancer.

Response of methanogenic system to long-term polycyclic aromatic hydrocarbon exposure: Adsorption and biodegradation, performance variation, and microbial function assessment.

Phenanthrene (PHE) as a typical polycyclic aromatic hydrocarbon (PAH) is prevalent and harmful to organisms in petroleum-polluted sites. The effects of PHE concentration levels on performance, microbial community and functions in methanogenic system were comprehensively investigated by an operation of UASB reactor (198 days) and a series of batch tests. The results found that PHE was prone to accumulate in reactor by sludge adsorption (Final concentration = 12.53 mg/g TS Sludge), which posed significant influences on methanogenic system. The removal of chemical oxygen demand (COD), NH4+-N and volatile fatty acids (VFAs) in reactor were reduced with PHE accumulation. Meanwhile, microbes with higher ATPase secrete more EPS activity to self-protect against PHE toxicity. Sequencing analysis showed that PHE interfered significantly diversity and structure of microbial community. For bacteria, PHE was toxic to Bacteroidetes and Latescibacteria, while syntrophs (f_Syntrophaceae, Syntrophorhabdus, etc.) involved in VFAs oxidation and aromatic organics degradation were tolerant of PHE stress. For archaea, acetoclastic methanogens (Methanosaeta) abundance was continuously diminished by 45.1% under long-term PHE exposure. Further functions analysis suggested that microbial community accelerated amino acid metabolism, energy metabolism and xenobiotics biodegradation & metabolism to satisfy physiological demanding under PHE stress. Combining batch tests of methanogenic metabolism proved that acetoclastic methanogenesis was negatively affected by PHE due to inhibition of functional enzymes (acetate kinase, phosphate acetyltransferase, etc.) expression. These findings may provide the basis for enhancing bioremediation of PAH pollution in anaerobic environment.

Anchoring ZnO on spinel cobalt ferrite for highly synergic sono-photo-catalytic, surfactant-assisted PAH degradation from soil washing solutions.

In this study, the photocatalytic activity of ZnO was effectively improved via its combination with spinel cobalt ferrite (SCF) nanoparticles. The catalytic performance of ZnO@SCF (ZSCF) was investigated in coupling with UV irradiation and ultrasound (US), as a heterogeneous sono-photocatalytic process, for the decontamination of phenanthrene (PHE) from contaminated soil. Soil washing tests were conducted in a batch environment, after extraction assisted by using Tween 80. Several characterization techniques such as XRD, FESEM-EDS, BET, TEM, UV-vis DRS, PL and VSM were utilized to determine the features of the as-prepared catalysts. ZSCF showed an excellent catalytic activity toward degradation of PHE in the presence of US and UV with a significant synergic effect. It was found that more than 93% of PHE (35 mg/L) and 87.5% of TOC could be eliminated by the integrated ZSCF/US/UV system under optimum operational conditions (pH: 8.0, ZSCF: 1.5 g/L, UV power: 6.0 W and US power: 70 W) within 90 min of reaction. After five times of use, ZSCF illustrated good reusability in the decontamination of PHE (87%) and TOC (79%). Quenching tests revealed the contribution of h+, HO• and e- species during PHE degradation over ZSCF/UV/US and an S-scheme photocatalytic mechanisms was proposed for the possible charge transfer routes under the ZSCF system. This study provides the important role of SCF in enhancing the ZnO photocatalytic activity due to its high performance, easy recovery and excellent durability, which it make an efficient and promising catalyst in environmental clean-up applications.

The Method and Study of Detecting Phenanthrene in Seawater Based on a Carbon Nanotube-Chitosan Oligosaccharide Modified Electrode Immunosensor.

Phenanthrene (PHE), as a structurally simple, tricyclic, polycyclic aromatic hydrocarbon (PAHs), is widely present in marine environments and organisms, with serious ecological and health impacts. It is crucial to study fast and simple high-sensitivity detection methods for phenanthrene in seawater for the environment and the human body. In this paper, a immunosensor was prepared by using a multi-wall carbon nanotube (MWCNTs)-chitosan oligosaccharide (COS) nanocomposite membrane loaded with phenanthrene antibody. The principle was based on the antibody-antigen reaction in the immune reaction, using the strong electron transfer ability of multi-walled carbon nanotubes, coupled with chitosan oligosaccharides with an excellent film formation and biocompatibility, to amplify the detection signal. The content of the phenanthrene in seawater was studied via differential pulse voltammetry (DPV) using a potassium ferricyanide system as a redox probe. The antibody concentration, pH value, and probe concentration were optimized. Under the optimal experimental conditions, the response peak current of the phenanthrene was inversely proportional to the concentration of phenanthrene, in the range from 0.5 ng·mL-1 to 80 ng·mL-1, and the detection limit was 0.30 ng·mL-1. The immune sensor was successfully applied to the detection of phenanthrene in marine water, with a recovery rate of 96.1~101.5%, and provided a stable, sensitive, and accurate method for the real-time monitoring of marine environments.