Removal Of Hydrocarbons Research Articles

Optimization and purification of bioproducts from Bacillus velezensis PhCL fermentation and their potential on industrial application and bioremediation

Bioproduction is considered a promising alternative way of obtaining useful and green chemicals. However, the downstream process of biomolecules has been one of the major difficulties in upscaling the application of bioproducts due to the high purification cost. Acid precipitation is the most common method for purifying biosurfactants from the fermentation broth with high purity. However, the use of strong acids and organic solvents in solvent extraction has limited its application. Hence, in this study, a new strain of Bacillus velezensis PhCL was isolated from phenolic waste, and its production of amylase had been optimized via response surface methodology. After that, amylase and biosurfactant were purified by sequential ammonium sulfate precipitation and the result suggested that even though the purified crude biosurfactant had a lower purification fold compared to the acid precipitation, the yield was higher and both enzymes and biosurfactant also could be recovered for lowering the purification cost. Moreover, the purified amylase and crude biosurfactant were characterized and the results suggested that the purified crude biosurfactant would have a higher emulsion activity and petroleum hydrocarbon removal rate compared to traditional surfactants. This study provided another approach for purifying bioactive compounds including enzymes and biosurfactants from the same fermentation broth and further explored the potential of the crude purified biosurfactant in the bioremediation of polycyclic aromatic hydrocarbons and petroleum hydrocarbons.

Advantages of residual phenol in coal chemical wastewater as a co-metabolic substrate for naphthalene degradation by microbial electrolysis cell

The use of co-metabolic substrates is effective for polycyclic aromatic hydrocarbons (PAHs) removal, but the potential of the high phenol concentrations in coal chemical wastewater (CCW) as a co-metabolic substrate in microbial electrolysis cell (MEC) has been neglected. In this study, the efficacy of varying phenol concentrations in comparison to simple substrates for degrading naphthalene in MEC under comparable COD has been explored. Results showed that phenol as a co-metabolic substrate outperformed sodium acetate and glucose in facilitating naphthalene degradation efficiency at 50 mg-COD/L. The naphthalene removal efficiency from RP, RA, and RG was found to be 84.11 ± 0.44 %, 73.80 ± 0.27 % and 72.43 ± 0.34 %, respectively. Similarly, phenol not only enhanced microbial biomass more effectively, but also exhibited optimal COD metabolism capacity. The addition of phenol resulted in a stepwise reduction in the molecular weight of naphthalene, whereas sodium acetate and glucose led to more diverse degradation pathways. Some bacteria with the potential ability to degrade PAHs were detected in phenol-added MEC, including Alicycliphilus, Azospira, Stenotrophomonas, Pseudomonas, and Sedimentibacter. Besides, phenol enhanced the expression of ncrA and nmsA genes, leading to more efficient degradation of naphthalene, with ncrA responsible for mediating the reduction of the benzene ring in naphthalene and nmsA closely associated with the decarboxylation of naphthalene. This study provides guidance for the effective co-degradation of PAHs in CCW with MEC, demonstrating the effectiveness of using phenol as a co-substrate relative to simple substrates in the removal of naphthalene.

Potential of some microbial isolates on diesel hydrocarbons removal, bio surfactant production and biofilm formation.

Potential of Arthrobacter citreus B27Pet, Bacillus thuringiensis B48Pet and Candida catnulata to produce biosurfactant using four different carbon sources (naphthalene, hexadecane, diesel and petroleum crude oil) was investigated. Removal of petroleum crude oil from aqueous culture and degradation of diesel were also determined using single and mixed culture of strains. The biofilm existence in single and mixed culture of strains was considered using naphthalene, hexadecane and diesel in culture medium. Cell surface hydrophobicity of A. citreus was higher than other isolates which also showed maximum surface tension reduction and emulsification index. As a whole, remarkable biosurfactant production occurred using petroleum crude oil as a carbon source in medium. A. citreus was found to be more robust than other tested strains in removal efficiency of crude oil due to its biosurfactant production capability. Statistically significant positive correlation was observed between biofilm existence and surface tension using diesel and hexadecane as carbon source. Overall diesel biodegradation efficiency by the mix culture of three applied strains was about 75% within a short period of time (10 days) which was accompanied with high biofilm production.

Simultaneous removal of crude oil and heavy metals by highly adapted bacterial strain Cutibacterium sp. NL2 isolated from Algerian oilfield.

Investigating the ability of bacteria to simultaneously enhance hydrocarbon removal and reduce heavy metals' toxicity is necessary to design more effective bioremediation strategies. A bacterium (NL2 strain) isolated from an Algerian oilfield was cultivated on crude oil as sole carbon and energy sources. Molecular analyses of the 16S rRNA gene sequence placed the strain within the Cutibacterium genera. This isolate was able to tolerate up to 60% of crude oil as sole carbon source. Chemical analyses (GC-MS) evidenced that strain NL2 was able to degrade 92.22% of crude oil (at optimal growing conditions: pH 10, 44 °C, 50 g L-1 NaCl, and 20% of crude oil (v/v) as sole carbon source) in only 7 days. NL2 isolate was also able to produce biosurfactants with reduction of surface tension of growing media (29.4 mN m-1). On the other hand, NL2 strain was able to tolerate high lead (Pb) and copper (Cu) concentrations (up to 60 mM). In fact, NL2 cultivated in the presence of 20% of crude oil, and 0.48 mM of Pb was able to reduce Pb concentration by a 41.36%. In turn, when cultivated on high Pb concentration (15 mM), the strain was able to remove 35.19% of it and 86.25% of crude oil, both in a time frame of 7 days. Our findings suggest that Cutibacterium strain NL2 is able to efficiently use and remove a wide range of crude oil substrates in presence of high Pb concentration. Accordingly, NL2 strain is of extreme interest from a biotechnological standpoint.

Gas stripping coupled with in-situ oxidation assisted microwave remediation of contaminated soil for efficient removal of polycyclic aromatic hydrocarbons (PAHs)

Thermal desorption technology at low temperatures has been extensively researched. However, the challenge remains in maintaining soil ecological function while effectively removing PAHs from contaminated soil using this method. Based on the gas hammer fragmentation concept, this study presents the strategy of gas stripping (steam extraction) coupled with microwave remediation. A multifunctional bluecoke-based modifier (MnO2/KHCO3@BC) was prepared followed by an investigation on the removal effect, soil characteristics and remediation mechanism of MnO2/KHCO3@BC-assisted microwave remediation of pyrene (PAHs model) contaminated soil. The research findings indicate that MnO2/KHCO3@BC is more effective in generating oxygen vacancies, facilitating surface electron transfer, and enhancing the oxidation effect of ROS on pyrene compared to KHCO3@BC and MnO2@BC. Despite having slightly inferior electromagnetic properties to BC, MnO2/KHCO3@BC could achieve a microwave remediation temperature of approximately 300 °C under optimal experimental conditions. MnO2/KHCO3@BC demonstrated remarkable pyrene removal efficiency with a maximum removal rate of 98.34%, making it an ideal candidate for pyrene remediation. Moreover, the remediated soil exhibited a weakly acidic nature, with a significant decrease in particle size and a substantial increase in potassium content. The study also highlighted a novel synergistic mechanism of ''microwave heating - gas stripping - oxidation,'' which can efficiently remove most of the pyrene adsorbed inside and outside of soil particles and degrade it into low-toxic and small-molecule organic matter, CO2, and H2O. Overall, the findings of this study could hold potential significance for upcoming endeavours concerning polluted industrial areas.

Surface Lattice-Embedded Pt Single-Atom Catalyst on Ceria-Zirconia with Superior Catalytic Performance for Propane Oxidation.

Tuning the metal-support interaction and coordination environment of single-atom catalysts can help achieve satisfactory catalytic performance for targeted reactions. Herein, via the facile control of calcination temperatures for Pt catalysts on pre-stabilized Ce0.9Zr0.1O2 (CZO) support, Pt single atoms (Pt1) with different strengths of Pt-CeO2 interaction and coordination environment were successfully constructed. With the increase in calcination temperature from 350 to 750 °C, a stronger Pt-CeO2 interaction and higher Pt-O-Ce coordination number were achieved due to the reaction between PtOx and surface Ce3+ species as well as the migration of Pt1 into the surface lattice of CZO. The Pt/CZO catalyst calcined at 750 °C (Pt/CZO-750) exhibited a surprisingly higher C3H8 oxidation activity than that calcined at 550 °C (Pt/CZO-550). Through systematic characterizations and reaction mechanism study, it was revealed that the higher concentration of surface Ce3+ species/oxygen vacancies and the stronger Pt-CeO2 interaction on Pt/CZO-750 could better facilitate the activation of oxygen to oxidize C3H8 into reactive carbonate/carboxyl species and further promote the transformation of these intermediates into gaseous CO2. The Pt/CZO-750 catalyst can be a potential candidate for the catalytic removal of hydrocarbons from vehicle exhaust.

Functional redundancy in response to runoff input upholds microbial community in hydrocarbon-contaminated land-sea continuum

An experimental approach mimicking the land-sea continuum in microcosms was developed in order to determine the effect of the terrigenous inputs by soil runoff on the microbial functional potential in hydrocarbon (HC) contaminated marine coastal sediment. We hypothesized that the coalescent event increases the functional potential of microbial communities in marine coastal sediments, influencing the fate of HC in marine coastal ecosystems.The microbial functional potential including the HC degradation ability was assessed by DNA-array to compare the sediment receiving or not terrigenous inputs. The removal of HC and the functional gene richness in sediment was unchanged with the terrigenous inputs. However, the gene variants (GVs) composition was modified indicating functional redundancy. In addition, functional indicators including GVs related to sulfite reduction, denitrification and polyaromatic degradation were identified in higher proportion in sediment receiving terrigenous inputs. The terrigenous inputs modified the functional co-occurrence networks, showing a reorganization of the GVs associations with an increase of the network complexity. Different keystone GVs ensuring similar functions were identified in networks with or without terrigenous inputs, further confirming functional redundancy.We argue that functional redundancy maintains the structure of microbial community in hydrocarbon-contaminated land-sea continuum mixing zone. Our results provide helpful functional information for the monitoring and management of coastal environment affected by human land-based activities.

Co-culture of Acinetobacter sp. and Scedosporium sp. immobilized beads for optimized biosurfactant production and degradation of crude oil

The widespread exploration and exploitation of crude oil has increased the prevalence of petroleum hydrocarbon pollution in the marine and coastal environment. Bioremediation of petroleum hydrocarbons using cell immobilization techniques is gaining increasing attention. In this study, the crude oil degradation performance of bacterial and fungal co-culture was optimized by entrapping both cells in sodium-alginate and polyvinyl alcohol composite beads. Results indicate that fungal cells remained active after entrapment and throughout the experiment, while bacterial cells were non-viable at the end of the experimental period in treatments with the bacterial-fungal ratio of 1:2. A remarkable decrease in surface tension from 72 mN/m to 36.51 mN/m was achieved in treatments with the bacterial-fungal ratio of 3:1. This resulted in a significant (P < 0.05) total petroleum hydrocarbon (TPH) removal rate of 89.4%, and the highest degradation of n-alkanes fractions (from 2129.01 mg/L to 118.53 mg/L), compared to the other treatments. Whereas PAHs removal was highest in treatments with the most fungal abundance (from 980.96 μg/L to 177.3 μg/L). Furthermore, enzymes analysis test revealed that catalase had the most effect on microbial degradation of the target substrate, while protease had no significant impact on the degradation process. High expression of almA and PAH-RHDa genes was achieved in the co-culture treatments, which correlated significantly (P < 0.05) with n-alkanes and PAHs removal, respectively. These results indicate that the application of immobilized bacterial and fungal cells in defined co-culture systems is an effective strategy for enhanced biodegradation of petroleum hydrocarbons in aqueous systems.

Application of photocatalytic proxone process for petrochemical wastewater treatment

Industrial wastewaters are different from sanitary wastewaters, and treatment complications due to their unique characteristics, so biological processes are typically disrupted. High chemical oxygen demand, dye, heavy metals, toxic organic and non-biodegradable compounds present in petroleum industry wastewater. This study intends to optimize the photocatalytic proxone process, utilizing a synthesized ZnO–Fe3O4 nanocatalyst, for petroleum wastewater treatment. The synthesis of ZnO–Fe3O4 was done by air oxidation and layer-by-layer self-assembly method and XRD, SEM, EDAX, FT-IR, BET, DRS, and VSM techniques were used to characterize the catalyst. Central composite design (CCD) method applied to investigated the effect of pH (4–8), reaction time (30–60 min), ozone gas concentration (1–2 mg/L-min), hydrogen peroxide concentration (2–3 mL/L) and the amount of catalyst (1–0.5 g/L) on the process. In the optimal conditions, biological oxygen demand (BOD5) and total petroleum hydrocarbon (TPH) removal, reaction kinetic, and synergistic effect mechanisms on the process were studied. Based on the ANOVA, a quadratic model with R2 = 0.99, P-Value = 0.0001, and F-Value = 906.87 was proposed to model the process. Based on the model pH = 5.7, ozone concentration = 1.8 mg/L-min, hydrogen peroxide concentration = 2.5 mL/L, reaction time = 56 min, and the catalyst dose = 0.7 g/L were proposed as the optimum condition. According to the model prediction, an efficiency of 85.3% was predicted for the removal of COD. To evaluate the accuracy of the prediction, an experiment was carried out in optimal conditions, and experimentally, a 52% removal efficiency was obtained. Also, at the optimum condition, BOD5 and TPH removal were 91.1% and 89.7% respectively. The reaction kinetic follows the pseudo-first-order kinetic model (R2 = 0.98). Also, the results showed that there is a synergistic effect in this process. As an advanced hybrid oxidation process, the photocatalytic proxone process has the capacity to treat petroleum wastewater to an acceptable standard.

Effects analysis on hydrocarbon removal performance of an adsorptive catalytic gasoline particulate filter in the gasoline engine during cold start

In order to remove hydrocarbon (HC) emission of the gasoline engine during cold start to meet increasingly stringent emission standards, the HC removal performance of a novel adsorptive catalytic gasoline particulate filter (A-CGPF) coated with new composite catalysts is investigated. Then, effects of different factors on HC removal (HC adsorption and conversion) of the A-CGPF during cold start are analyzed. The results show that during first 40 s of the cold start, the cumulative emission of hydrocarbon is greatly reduced. Ambient temperature has a great influence on hydrocarbon removal in the early stage of cold start, and its variation has little effect on MMC. The order of hydrocarbon removal performance during cold start under non-adiabatic condition is MRP > MMC > MP > MC > MPCZ, and the difference of hydrocarbon removal rate between MMC and MRP is only 5%–9%. In addition, the larger ratio of oxidizing components and reductive components λ can lead to the faster temperature rise and the greater hydrocarbon removal rate. The λ value has little influence on the early stage of cold start, but gradually increases the influence on the late stage of that until it is up to 0.95. During soot capture, the ash accumulation has a more significant effect on HC abatement at the late stage of cold start, which can delay the temperature rise in the filter and slightly decrease the hydrocarbon removal rate. This work provides reference for enhancing simultaneous hydrocarbon and soot reduction performance of the A-CGPF under the low temperature and design of coupled after-treatment system.

Phytoremediation Potential of &lt;i&gt;Ficus Benjamina&lt;/i&gt; for the removal of Naphthalene, Acenaphthene and Phenanthrene in Contaminated Soil

This study was undertaken to evaluate the phytoremediation potential of Ficus Benjamina plant for the removal of polycyclic aromatic hydrocarbons (PAHs): Acenaphthene (ACN), naphthalene (NAP) and phenanthrene (PHE) from contaminated soil. The plant was transplanted into pot containing 4 kg soil spiked with the PAHs: ACN, NAP and PHE at concentrations of 1600, 2000 and 2400 mg respectively. A separate pot with untreated soil was used as a control. Irrigation was done with 600 mL of water after every three days in the evening hours for eight weeks. Samples of the plant and soil were collected at the end of the phytoremediation process; the plant was washed with tap water and carefully separated into roots and shoots, dried along with the soil, ground and sieved. The sieved soil, roots, shoots of the experimental plant as well as that of the control were analyzed for the levels of PAHs: ACN, NAP and PHE following Soxhlet extraction with 200 mL of dichloromethane-acetone (1:1 v/v) at 60 oC for 6 hours using high performance liquid chromatography (HPLC). The bioconcentration factor (BCF) in mg/kg and the Translocation Factor (TF) in mg/kg of Ficus Benjamina for ACN, NAP and PHE were (1.76 and 0.47), (0.54 and 2.7) and (0.93 and 0.68) respectively. The results generated in this study have demonstrated that the different concentrations of the PAHs (NAP, ACN and PHE) in root, only NAP was transferred to the aerial parts of the plant and this suggests the suitability of Ficus Benjamina for the phytoremediation of NAP.

Preparation of activated carbon adsorption materials derived from coal gasification fine slag via low-temperature air activation

Considering the considerable amount of residual carbon in coal gasification fine slag (CGFS) and the issue of lacking effective treatments, it is imperative to put forward a large-scale, green, and efficient method, achieving quantity reduction and harmless disposal. A kind of activated carbon adsorption material was prepared from CGFS with abundant carbon content (nearly 33.61 wt%) by low-temperature air activation. The CGFS-20 showed the best performance, whose specific surface area and pore volume increased by 21.5% and 7.8%, respectively. It is attributed to the slight oxidation of combustibles (main carbon) and removal of hydrocarbons blocked in pores, which can be further confirmed by FT-IR and pore analysis. In addition, the pores generated through activation are more concentrated in the 1.4–5 nm range. While the proportion of micropores, mesopores, and macropores of different activated samples did not change significantly, implying that the generation and development of pores make it realize a dynamic balance of three pore proportions. The CO2 adsorption of CGFS and CGFS-20 combined with the Langmuir model was investigated and revealed that the theoretical maximum adsorption for CO2 was 21.03 cm3/g.

Mycoremediation of Iranian Crude Oil Contaminated Soil by Indigenous Fungi Isolates and the Evaluation of Their Bioremediation Ability

Bioremediation is one of the most effective approaches to eliminate or reduce soil contamination. Samples were collected from petroleum-contaminated soil in Oil Refinery Plant in Isfahan, Iran. The soil samples were cultured and the isolates were identified by polymerase chain reaction method. Total petroleum hydrocarbons assessment and measurement of the absorbance at 420 nm were used to determine the capability of fungi for bioremediation of petroleum hydrocarbons. Five isolates of fungi were purified from petroleum-contaminated soils. The oil degrading fungal isolates were identified as Aspergillus niger, Rhodotorula mucilaginosa, Penicillium sp., Penicillium chrysogenum, and Mucor circinelloides. All isolates had mycoremediation activity among which, Aspergillus niger, Mucor circinelloides, and Penicillium sp. had the highest potential to reduce total petroleum hydrocarbons (85%, 64%, and 53%, respectively) during 3 months. In addition, biosurfactant-producing ability was found only in these three isolates. The A. niger isolate had a high ability in hydrocarbons removal and, the P. chrysogenum isolate had significant ability in biosurfactant production, they can be applied in the bioremediation of contaminated soil in microbial consortia. The use of native microorganisms living in contaminated soils, especially fungi, have a high efficiency in removing contaminants of petroleum hydrocarbons in the soil.

Comparative study of bioremediation of crude oil spillage using Cissus populnea stem and root as bio-sorbents

The total petroleum hydrocarbon concentration decrease at the initial and final bioremediation across different variable and the comparative effect of roots and stem of Cisuss populnea biosorbent were studied. 25 g of soil was weighed into different plate, contaminated with about 10 ml of crude oil, the plate was labeled as BI, CI DI, BF, CF and DF (stem), (root) across 3 g, 6 g, and 9 g variables and A (soil and crude oil mixture) as control for initial and final bioremediation. 1 g of each contaminated soil sample was extracted using mechanical shaker at room temperature and the extracts were analyzed using GC/MS the results showed that the initial treatment of stem biosorbent were 358.47455 ppm, 248.02045 ppm, 249.97273 ppm respectively and the final treatment after 4 weeks of biodegradation were 173.40636 ppm, 70.44364 ppm, 45.60818 ppm and control 757.39864 ppm. The total effect removal of Total petroleum hydrocarbon obtained were 51.6%, 75.2% and 81.8%, while the initial treatment of the root biosorbent were 366.72762 ppm, 347.75909 ppm, 337.04227ppm, after 4 weeks of biodegradation, the Total petroleum hydrocarbon concentration decreases to 143.6982 ppm, 60.05455 ppm, 52.21045 ppm and control 757.39864 ppm and the effect removal were 60.8%, 82.7% and 84.5%.

Gimibacter soli gen. nov. sp. nov., isolated from mangrove soil and insight into its ecological distribution and metabolic potential.

A Gram-stain-negative, facultatively anaerobic, motile and rod-shaped bacterium, designated as 6D33T, was isolated from mangrove soil. Growth was found to occur at 15-32 °C (optimum, 28 °C), at pH 6-9 (optimum, pH 7) and in 0-3 % NaCl (optimum, 1 %, w/v). The results of 16S rRNA gene-based analysis showed that strain 6D33T belonged to the family Temperatibacteraceae, sharing 93.1-94.4 % identity with its close neighbours within the genus Kordiimonas. The phylogenomic results indicated that strain 6D33T formed an independent branch distinct from type strains of the genus Kordiimonas. The overall genome relatedness indices of digital DNA-DNA hybridization, average nucleotide identity and amino acid identity values showed that strain 6D33T represents a novel species of a novel genus. The results of chemotaxonomic characterization indicated that the major cellular fatty acids of strain 6D33T were summed feature 9 (C16 : 0 10-methyl and/or iso-C17 : 1 ω9c), summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c) and iso-C15 : 0; the polar lipids comprised diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unidentified aminolipid and three unidentified lipids; the only respiratory quinone was ubiquinone-10. The genomic size and DNA G+C contents were 3.59 Mbp and 60.84 mol%, respectively. The 16S rRNA gene sequence reads abundance profiles revealed that the rare taxon is prevalent in marine environments, especially in sediments. Genome-scale metabolic reconstruction of strain 6D33T revealed a heterotrophic lifestyle and many pathways responsible for the degradation of aromatic compounds, suggesting application potential in aromatic hydrocarbon removal. Based on its genotypic and phenotypic characteristics, strain 6D33T is concluded to represent a novel species of the novel genus in the family Temperatibacteraceae, for which the name Gimibacter soli gen. nov. sp. nov. is proposed. The type strain of the type species is 6D33T (=GDMCC 1.1959T=KCTC 82335T).

Comparison of exogenous degrader-enhanced bioremediation with low-dose persulfate oxidation for polycyclic aromatic hydrocarbon removal in alkaline soil: efficiency and influence on ecological health

Comparison of exogenous degrader-enhanced bioremediation with low-dose persulfate oxidation for polycyclic aromatic hydrocarbon removal in alkaline soil: efficiency and influence on ecological health

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.

Efficient biodegradation of trimethoprim and transformation mechanism using the photoelectrocatalytic system

In this study, the coupling of a three-electrode photocatalytic microbial fuel cell system (PMFC) was established for trimethoprim (TMP) degradation, to achieve efficient degradation and electrical energy production simultaneously. The photocatalytic bioanode, degradation performance, electrochemical characteristics and microbial structure were analyzed to explore the degradation of TMP in PMFC. The results showed that rapid degradation and enhanced mineralization of TMP were obtained in the PMFC, which were 1.7 and 1.4 times higher than those of traditional microbial fuel cells (MFCs), respectively. Intermediates in the degradation process were identified in both systems, and three degradation pathways were inferred in the PMFC. The electricity characteristics were investigated and superior electrical production and higher electron transfer efficiency were observed in the PMFC, resulting in a maximum power density of 75.1 mW/m2 and a maximum voltage of 0.225 V. Additionally, the cyclic voltammetry test and electrochemical impedance spectra were used for electrochemical performance characterization, and the results showed the stronger oxidation ability of PMFC with half the charge transfer resistance of MFCs. The microbial community structure demonstrated that the dominant species were enriched and coexisted, involving degradation bacteria, exoelectrogens, and hydrocarbon removal bacterial. Furthermore, canonical correspondence analysis (CCA) revealed a mutual promotion of TMP degradation and electricity production with the involvement of these active genera. In conclusion, this novel technology is an excellent alternative in practical applications for the treatment of wastewater containing antibiotics.

Detection and Removal of Polycyclic Aromatic Hydrocarbon from Selected Areas in Tigris River in Baghdad City

Aromatic hydrocarbons present in Iraqi national surface water were believed to be raised principally from combustion of various petroleum products, industrial processes and transport output and their precipitation on surface water.Polycyclic aromatic hydrocarbons (PAHs) were included in the priority pollutant list due to their toxic and carcinogenic nature. The concern about water contamination and the consequent human exposure have encouraged the development of new methods forPAHs detection and removal.PAHs, the real contaminants of petroleum matter, were detected in selected sites along Tigris River within Baghdad City in summer and winter time, using Shimadzu high performance liquid chromatography (HPLC) system.Analysis of samples from selected sites proved that the most abundant component of aromatic hydrocarbons were phenanthrene naphthalene, and acenaphthylene, followed by fluorene, acenaphthene, fluoranthene, benzo (a) pyrene, anthracene. and pyrene werepresent in low concentrations ranging in a descending order. Chrysene and benzo (a) anthracene were found in very low concentration.A laboratory unit was designed to optimize the factors which may influence the feasibility of degradation processes of naphthalene and phenanthrene in aqueous matrices by oxidation with Fenton reagent. The study proved that 83% and 79% removal of naphthalene and phenanthrene were achieved applying optimum conditions of pH=3, temperature=40 ° C, H2O2=50 ppm and Fe2+ catalyst = 6 ppm

Phytoremediation and bacterial community dynamics of diesel- and heavy metal-contaminated soil: Long-term monitoring on a pilot scale

The objective of this study was to investigate the long-term phytoremediation characteristics and the bacterial community structure in diesel- and heavy metals-contaminated soil on a pilot scale. Soil was contaminated with diesel, Cu, Pb, and Cd. Festuca arundinacea (tall fescue) seedlings were cultivated in the co-contaminated soil, and the phytoremediation performance was monitored for 571 days. The maximum total petroleum hydrocarbon (TPH) removal rate was 62.6%, with residual TPHs remaining at the end of the experiment. Of the three heavy metals, Cd had the highest uptake efficiency in tall fescue, with a bioconcentration factor of 0.58. In the bacterial community, the most dominant bacterial genera exhibited either petroleum hydrocarbon biodegradability or heavy-metal tolerance. Correlation analysis revealed that ambient temperature did not significantly affect phytoremediation performance, while soil pH and organic content had significant effects on pollutant concentrations in the soil. The results of this study, obtained from the long-term monitoring of phytoremediation on a pilot scale, provide useful information on pollutant behavior and bacterial community dynamics that can be employed in the development of phytoremediation strategies for soils co-contaminated with diesel and heavy metals.