Removal Of Dibutyl Phthalate Research Articles

Removal of dibutyl phthalate (DBP) by bacterial extracellular polymeric substances (EPS) via enzyme catalysis and electron transmission

Phthalic acid esters (PAEs) showed high environmental risk due to the widely existence and toxicity. Microbial-excreted extracellular polymeric substances (EPS) showed potential of degrading organic compounds. In this study, the degradation ability and the mechanisms of EPS from two bacteria (PAEs degrader Gordonia sihwensis; electrochemically active strain Shewanella oneidensis MR-1) were investigated. Results showed that EPS of the two bacteria had different composition of C-type cytochromes, flavins, catalase, and α-glucosidase. The removal of dibutyl phthalate (DBP) by total EPS were 68% of G. sihwensis and 72% for S. oneidensis. For both bacteria, the degradation rates k of EPS were as TB-EPS > LB-EPS > S-EPS. The degradation mechanisms of EPS from the two bacteria showed difference with electrochemical active components mediated electron transmission for S. oneidensis MR-1 and enzymes catalysis for G. sihwensis. Results of this study illustrated the variation of the contribution of active components of EPS to degradation.

Dibutyl phthalate degradation by Paenarthrobacter ureafaciens PB10 through downstream product myristic acid and its bioremediation potential in contaminated soil

Dibutyl phthalate (DBP) is a widely used plasticizer to make plastic flexible and long-lasting. It is easily accessible in a broad spectrum of environments as a result of the rising level of plastic pollution. This compound is considered a top-priority toxicant and persistent organic pollutant by international environmental agencies for its endocrine disruptive and carcinogenic propensities. To mitigate the DBP in the soil, one DBP-degrading bacterial strain was isolated from a plastic-polluted landfill and identified as Paenarthrobacter ureafaciens PB10 by 16S rRNA gene sequence-based homology. The strain was found to develop a distinct transparent halo zone around grown colonies on an agar plate supplemented with DBP. The addition of yeast extract (100 mg/L) as a nutrient source accelerated cell biomass production and DBP degradation rate; however, the presence of glucose suppressed DBP degradation by the PB10 strain without affecting its ability to proliferate. The strain PB10 was efficient in eliminating DBP under various pH conditions (5.0–8.0). Maximum cell growth and degradation of 99.49% at 300 mg/L DBP were achieved in 72 h at the optimized mineral salt medium (MS) conditions of pH 7.0 and 32 °C. Despite that, when the concentration of DBP rose to 3000 mg/L, the DBP depletion rate was measured at 79.34% in 72 h. Some novel intermediate metabolites, like myristic acid, hexadecanoic acid, stearic acid, and the methyl derivative of 4-hydroxyphenyl acetate, along with monobutyl phthalate and phthalic acid, were detected in the downstream degradation process of DBP through GC-MS profiling. Furthermore, in synchronization with native soil microbes, this PB10 strain successfully removed a notable amount of DBP (up to 54.11%) from contaminated soil under microcosm study after 10 d. Thus, PB10 has effective DBP removal ability and is considered a potential candidate for bioremediation in DBP-contaminated sites.

Optimizing concentration and interaction mechanism of Demodesmus sp. and Achromobacter pulmonis sp. consortium to evaluate their potential for dibutyl phthalate removal from synthetic wastewater

A green approach of Desmodesmus sp. to Achromobacter pulmonis (1:1) coculture ratios was optimized to improve the removal efficiency of dibutyl phthalate (DBP) from simulated wastewater. High DBP resistance bacterial strains and microalgae was optimized from plastic contaminated water and acclimation process respectively. The influence of various factors on DBP removal performance was comprehensively investigated. Highest DBP removal 93 % was recorded, when the ratios algae-bacteria 1:1, with sodium acetate, pH-6, shaking speed-120 rpm and lighting periods L:D-12:12. Enough nutrient (TN/TP/TOC) availability and higher protein-108 mg/L and sugar-40 mg/L were observed in presences of 50 mg/L DBP. The degradation and sorption were calculated 81,12; 27,39 & 43,12 % in algae-bacteria, only algae and only bacteria system respectively. The degradation kinetics t1/2 3.74,22.15,12.86 days were evaluated, confirming that algae-bacteria effectively degrade the DBP. This outcome leading to promote a green sustainable approach to remove the emerging contamination from wastewater.

Synthesis of compressible and reusable chitin/O-gCN sponges for efficient removal of phthalate esters in water environments

Phthalate esters (PAEs) widely used as plasticizers in industrial products are a major threat to human health and water ecological security. In this work, chitin-based sponges doped with oxygen-modified graphitic carbon nitride (O-gCN) (ChCN) demonstrated adsorption-photocatalytic synergistic ability for the efficient removal of two typical PAEs, diethyl phthalate (DEP) and dibutyl phthalate (DBP). The addition of O-gCN increased the sponge mechanical strength from 0.629 to 1.39 MPa, enabling materials with interconnected pores, excellent compressibility, and mechanical durability. The saturated adsorption capacities of DEP and DBP reached 37.41–42.93 mg g−1 for ChCN sponges, wherein the driving forces were hydrophobic interactions, hydrogen bonding, and π-π interactions. Notably, O-gCN significantly improved PAE removal by simultaneously enhancing the adsorption and photocatalytic effect of ChCN sponges due to its high catalytic activity, leading to 100% removal of DEP and DBP within 2 h. The degradation pathway of DEP was confirmed to be de-esterification. Finally, filtration columns assembled with ChCN sponges showed 87.8–90.9% PAE removal from water under natural light, and the removal efficiency did not significantly change even after three reuses, indicating stable removal performance and good reusability with potential for practical applications. The sponges also possessed good biocompatibility and biodegradability, as demonstrated through algal toxicity experiments and biodegradation tests. Therefore, this research presents a convenient method for preparation of compressible and reusable sponge materials from renewable biomass for efficient PAE removal from aqueous environments and has revealed the underlying mechanisms of such removal by the adsorption-photocatalysis synergistic effect.

Unraveling the crucial role of Mo2N from Fe/Mo bimetal MOF-derived catalyst in initiating Fe3+/Fe2+ redox cycle to activate peroxymonosulfate for dibutyl phthalate degradation

Phthalic acid esters (PAEs) pose serious health risks to humans and are difficult to remove by conventional sewage treatment processes. Herein, Fe2Mo3O8/MoO2/Mo2N composite (FMON) derived from bimetallic organic framework was used to activate peroxymonosulfate (PMS) for dibutyl phthalate (DBP) degradation. FMON exhibited an excellent catalytic effect with DBP removal efficiency of 92.4 % within 60 min. Mo2N showed a superior ability in promoting Fe3+/Fe2+ redox cycle. The reduction efficiencies of Fe3+ by Mo2N/MoO2 composite and MoO2 were 67 %–94 % and 11 %–23 %, respectively, in the homogeneous comparative experiment. Moreover, the ratio of Fe2+/Fe3+ in FMON increased significantly after the catalytic reaction. Fe element doping also enhanced the reuse stability and reduced the metal ion leaching of the catalyst. The degradation of DBP was mediated by a variety of reactive species, of which SO4−, OH and O2− were dominant. Fe element, Mo element and O vacancies were confirmed to exert significant contributions as active sites in the catalytic process. Three degradation pathways of DBP were obtained by DFT calculation and HPLC-MS analysis. And the toxicity of DBP degradation products was significantly reduced based on the assessment result of Toxicity Estimation Software Tool (T.E.S.T.). This study explored a novel Fe/Mo bimetallic catalyst with friendly Fe3+/Fe2+ cycling for environmental catalysis and provided new ideas for the treatment of PAEs wastewater.

Enhanced removal of dibutyl phthalate in a laccase-mediator system: Optimized process parameters, kinetics, and environmental impact

The persistence and recalcitrance of endocrine-disrupting chemicals (EDCs) in the environment have raised momentous concerns due to their carcinogenic, teratogenic, genotoxic, and cytotoxic effects on humans, animals, and plants. Unarguably, dibutyl phthalate (DBP) is one of the most ubiquitous EDCs because of its bioavailability in water, soil, and atmosphere. This study aims to investigate the efficiency of Agaricus bisporus laccase in the degradation of dibutyl phthalate (DBP) in laccase-mediator system. Here, enhanced removal efficiency was recorded during DBP degradation in laccase-mediator systems than in reaction medium containing laccase only. About 98.85% of 30 mg L−1 DBP was efficiently removed in a medium containing 1.3 U mL−1, 0.045 mM Syringaldehyde (SYR) at incubation temperature 30 aC and pH 5 within 24 h. This finding was further corroborated by the synergistic interplay of the optimal parameters in the laccase-SYR system done using response surface methodology (Box-Behnken Design). Furthermore, the addition of 1.5 mM of metal ions in the laccase-SYR system further promoted the enhanced removal of DBP in the following order: Cr3+> Pb2+> Ca2+> Al3+>Zn2+ > Cu2+. A significant decrease in DBP degradation was observed at higher concentrations of metal ions above 1.5 mM due to the inhibition of laccase active sites. The coefficient of correlation (R2 = 0.9885) recorded in the Lineweaver bulk plot affirmed that the removal efficiencies are highly dependent on DBP concentration in the laccase-SYR system. The Gas-Chromatography Mass Spectrometry (GC-MS) analyses affirmed that the ortho-cleavage due to hydrolysis of DBP in the reaction system led to the formation of two metabolic degradation products (MBP and PA). The phytotoxicity assessment affirmed the detoxified status of DBP after treatment with significant improvement (90 and 91%) in the growth of Lens culinaris and Sorghum bicolor. This is the first report on DBP degradation in the laccase-SYR reaction system, underscoring the unique, eco-friendly, economical, and promising alternative to known conventional methods.

Fluorescent labeling and tracing of immobilized efficient degrading bacterium DNB-S1 and its remediation efficiency of DBP contaminated soil

Dibutyl phthalate (DBP) is an organic pollutant frequently detected in soil, and is a reproductive poison that harms animals both before and after birth and has mutagenic, teratogenic, and carcinogenic effects. DBP removal from farmland has been the subject of extensive research in recent years. Efficient DBP degrading bacterial strains were screened in the laboratory. GFP (Green fluorescent protein) labeled degradation strain GFP-DNB-S1 was analyzed for its activity and dynamics. Using sodium alginate (SA) and nano-hydroxyapatite (n-HAP) as carrier materials and CaCl2 as a cross-linking agent, the immobilized microbial agent n-HAP/SA + DNB-S1 was prepared by embedding cross-linking immobilization technology to study the remediation effect of DBP contaminated soil. The best formation effect of immobilized materials (n-HAP/SA) was found when the SA to n-HAP ratio was 3:2. When compared to single SA immobilized bacteria, n-HAP/SA immobilized bacteria improved the surface roughness and porosity of the microspheres. After 70 days, LED light revealed that the immobilized bacteria's GFP green fluorescent protein expression was stable. At 70 days, the initial DBP concentration of 500 mg ∙ L−1 degraded at a rate of 69.9%. The degrading bacteria had no effect on DBP degradation before and after being labeled with GFP. The n-HAP/SA immobilized bacteria offered a better living environment for microorganisms due to their rougher surface and a greater number of pores. This protected the microorganisms and increased the efficiency of DBP degradation. When the concentration of DBP in contaminated soil was set to 20 mg ∙ kg−1 and the n-HAP/SA + DNB-S1 immobilized bacterial agent was applied to the soil, the rate of DBP degradation was determined to be 93.34%. The degradation process followed First-order degradation kinetics, which improved the physical and chemical properties of the soil as well as its fertility.

Degradation of dibutyl phthalate by ozonation in the ultrasonic cavitation-rotational flow interaction coupled-field: performance and mechanism.

Dibutyl phthalate (DBP) is present in hydraulic fracturing flowback and produced water. Degradation of DBP in aqueous by means of ozonation in ultrasonic cavitation-rotational flow interaction coupled-field (UC-RF coupled-field) was studied. The effect of ozone dosage, ozone intake flow, operating temperature, initial pH, DBP initial concentration, liquid flow rate, and ultrasonic power on the DBP removal was investigated. Results indicated that the DBP degradation rate was strongly influenced by the liquid flow rate and the ultrasonic power over the range investigated. HCO3- and Cl- revealed an inhibitory effect on the DBP removal. SO42- seemed to have no effect on DBP removal. The ozone utilization efficiencies in the UC-RF coupled-field were 2.77 and 1.13 times higher than those in the conventional microporous aeration (CMA) and rotating-flow microbubble aeration (RFMA), respectively. The DBP degradation rate was diminished in the presence of tert-butyl alcohol. Cavitation bubbles are considered as innumerable microreactors. Degradation of DBP by direct ozonation, hydroxyl radical (·OH) oxidation, high pressure, and high-temperature pyrolysis was demonstrated. Finally, a possible degradation pathway of DBP is obtained on the basis of the main reaction intermediates.

Modification of Ti/TiO2NT with ZrO2 nanoparticles to enhance photoelectrocatalytic performance in removal of dibutyl phthalate.

This work shows that ZrO2, used as a modifier of TiO2, can be highly effective as a co-catalyst in the photoelectrocatalytic degradation of dibutyl phthalate (DBP). The monoclinic phase of ZrO2 was easily obtained by chemical deposition on TiO2 nanotubes (Ebg ~3.06 eV), increasing the occurrence of hydroxyl groups and acidity on the surface of the material, as observed by electrophoretic mobility measurements. The optimized photoelectrocatalysis conditions were bias potential of 1.5 V, 0.1 M Na2SO4 (initial pH 6) supporting electrolyte, 6 ppm of DBP, and UV/Vis irradiation. These conditions resulted in complete removal of DBP, down to the limit of detection of the chromatographic method used, with up to complete TOC removal after 60 min of treatment. The effects of pH, bias potential, DBP concentration, and applied potential were investigated. The method was compared with photocatalysis and photolysis. An oxidation mechanism is proposed, based on intermediates detected by LC-MS/MS during 10 min of photoelectrocatalysis.

Estrogenic activity and ecological risk of steroids, bisphenol A and phthalates after secondary and tertiary sewage treatment processes

Effluents of sewage treatment plants (STPs) are an important source of estrogenic substances to the receiving water bodies affecting their ecological safety. In this study, steroids, bisphenol A (BPA) and phthalates were assessed in the secondary (SE) and tertiary effluent (TE) of three typical urban STPs in Beijing (China). In addition, the overall estrogenic activity in these effluents was assessed by an in-vitro bioassay (ERE-CALUX). Results showed that the concentrations and activities of estrogenic compounds in TE were lower than those in SE. The residual concentration of 17β-estradiol (E2) was the highest among the detected steroids, accounting for 51.6 ± 5.1% in SE and 57.5 ± 24.8% in TE. The residual level (25.2–41.6 ng/L) of BPA in effluents was significantly higher than that of steroids (0.2–28.8 ng/L). The residual concentration of diethyl phthalate was the highest among the detected phthalates accounting for 47.1 ± 5.1% in SE and 37.6 ± 11.5% in TE. Steroids and BPA had a higher removal rate (83.5% and 96.7%) in secondary and tertiary treatment than phthalates (68.8% and 83.1%). The hydrophobic characteristics of these estrogenic compounds determined the removal mechanism. The removal of steroids, BPA, dimethyl phthalate and diethyl phthalate (LogKow= 1.61–4.15) mainly occurred through biodegradation in the water phase, while the removal of dibutyl phthalate, butylbenzyl phthalate and di(2-ethylhexyl) phthalate (LogKow= 4.27–7.50) mainly occurred in the solid phase after adsorption on and sedimentation of the suspended particulate matter. According to ERE-CALUX, the estrogenic activity in the final STP effluents was 3.2–45.6 ng E2-equivalents/L, which is higher than reported levels in the effluents of European STPs. Calculation of estrogenic equivalents by using substance specific chemical analysis indicated that the dominant contributor was E2 (56.4–88.4%), followed by 17α-ethinylestradiol (EE2) (4.1–34.8%), both also exerting a moderate risk to the aquatic ecosystem. While the upgrade of treatment processes in STPs has efficiently reduced the emission of estrogenic substances, their ecological risk was not yet phased out.

Electrochemical degradation performance and mechanism of dibutyl phthalate with hydrophobic PbO2 electrode

A polytetrafluoroethylene (PTFE) doped PbO2 anode with a highly hydrophobicity was fabricated by electrodeposition method. In this process, vertically aligned TiO2 nanotubes (TiO2NTs) are formed by the anodic oxidation of Ti plates as an intermediate layer for PbO2 electrodeposition. The characterization of the electrodes indicated that PTFE was successfully introduced to the electrode surface, the TiO2NTs were completely covered with β-PbO2 particles and gave it a large surface area, which also limited the growth of its crystal particles. Compared with the conventional Ti/PbO2 and Ti/TiO2NTs/PbO2 electrode, the Ti/TiO2NTs/PbO2-PTFE electrode has enhanced surface hydrophobicity, higher oxygen evolution potential, lower electrochemical impedance, with more active sites, and generate more hydroxyl radicals (·OH), which were enhanced by the addition of PTFE nanoparticles. The electrocatalytic performance of the three electrodes were investigated using dibutyl phthalate (DBP) as the model pollutant. The efficiency of the DBP removal of the three electrodes was in the order: Ti/TiO2NTs/PbO2-PTFE > Ti/TiO2NTs/PbO2 > Ti/PbO2. The degradation process followed the pseudo-first-order kinetic model well, with rate constants of 0.1326, 0.1266, and 0.1041 h−1 for the three electrodes, respectively. The lowest energy consumption (6.1 kWh g−1) was obtained after 8 h of DBP treatment using Ti/TiO2NTs/PbO2-PTFE compared to Ti/TiO2NTs/PbO2 (6.7 kWh g−1) and Ti/PbO2 (7.4 kWh g−1) electrodes. Moreover, the effects of current density, initial pH and electrolyte concentration were investigated. Finally, the products of the DBP degradation process were verified based on gas chromatography-mass spectrometry analysis, and possible degradation pathways were described.

Applying Ultrasound/Hydrogen Peroxide System for Dibutyl Phthalate Removal from Aqueous Solution with a Focus on Optimization by a Response Surface Method: Effective Factors, Mineralization and Biodegradability Studies

Applying Ultrasound/Hydrogen Peroxide System for Dibutyl Phthalate Removal from Aqueous Solution with a Focus on Optimization by a Response Surface Method: Effective Factors, Mineralization and Biodegradability Studies

Preparation of multi-walled carbon nanotubes based magnetic multi-template molecularly imprinted polymer for the adsorption of phthalate esters in water samples.

Taking the advantages of surface imprinting, multi-template imprinting and magnetic separation, a novel magnetic multi-template molecularly imprinted polymer (mag-MMIP@MWCNTs) was prepared by using MWCNTs as support material, Fe3O4 as magnetic core, and dimethyl phthalate (DMP), diethyl phthalate (DEP), and dibutyl phthalate (DBP) as template molecules. This composite was characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), and the Brunauer-Emmett-Teller (BET) analysis, and was used for the simultaneous adsorption of DMP, DEP, and DBP in aqueous solution. The effects of solution pH, contact time, PAEs initial concentration, temperature, adsorption selectivity, and reusability were investigated and discussed in detail. The results demonstrated that mag-MMIP@MWCNTs exhibited fast kinetics, good magnetic separation, and excellent selectivity for the adsorption of three phthalate esters (PAEs). The adsorption kinetics followed pseudo second-order kinetic model and the adsorption thermodynamics followed Langmuir isothermal model very well, and the maximum adsorption capacities (Qmax) of DMP, DEP, and DBP were obtained as 0.95, 1.38, and 7.09 mg g-1, respectively. The Scatchard analysis revealed that the template-polymer system had a two-site binding behavior. The adsorption thermodynamic studies indicated that the adsorption processes were exothermic and spontaneous, and dominated by physical adsorption relying on hydrogen bond, hydrophobic interaction, and van der Waals force. Mag-MMIP@MWCNTs also showed good reproducibility and reusability for simultaneous adsorption of the three PAEs. The potential application of mag-MMIP@MWCNTs was proved by the removal of DMP, DEP, and DBP spiked in environmental water samples.

Decomposition of dibutyl phthalate in goat whey solution by different catalytic ozonation treatments: Performance and efficiency

For efficient decomposition of dibutyl phthalate (DBP) in goat whey solution, we are using ozone (O 3 ), ozone with zinc oxide (O 3 /ZnO), and ozone with zinc oxide and activated carbons (O 3 /ZnO/ACs) systems through catalytic ozonation process. The performance and efficiency of system were evaluated. The results showed that ozonation of sample using O 3 /ZnO/ACs system was found to be the most efficient for the DBP degradation. A maximum DBP degradation value of 99.04% was achieved after ozonation of whey solution using O 3 /ZnO/ACs system at O 3 dosage 15 mg/L, pH 4, and 80 min. The ozonation treatments did not result in significant changes in protein, lactose, and ash content of whey ( P > 0.05), while the fat content of whey decreased after ozonation. The results indicated that catalytic ozonation using O 3 /ZnO/ACs system can be suggested as an efficient process for the removal of DBP from contaminated whey and dairy products to prevent potential adverse health effect. • O 3 /ZnO/ACs system is the most efficient for DBP degradation in goat whey. • The maximum degradation value of DBP could achieved to 99.04% by using O 3 /ZnO/ACs system. • The degradation of DBP was depended on reaction time, pH value, and catalyst dosage. • Greater degradation rate of DBP was found at acidic pH. • O 3 /ZnO/ACs system at O 3 dosage 15 mg/L, pH 4, and 80 min was appropriate treatment for whey.

Reclamation of aqueous solution synthetically polluted with endocrine disturbing chemicals by commercial NF membrane

The target of this study is the removal of Di butyl phthalate, Bisphenol – A and Paracetamol as endocrine disrupting chemicals from aqueous solution using NF99 as a commercial nanofiltration membrane at different operating parameters of pressures (10, 20 and 30 bar), pH (3-11) and different EDCs concentrations using % TOC removal as indicator for the efficiency of the understudied membrane. It was found that the % TOC rejection of Paracetamol was the highest (86 %) at pH 10. The endocrine disrupting chemicals rejection was detected to be increased with the increase of operating pressure till 20 bar. The impactt of pH on %TOC removal of EDCs was altered depending on the pka of each compound. Moreover, the anti-fouling property of NF 99 membrane has been investigated by evaluating the membrane rejection and flux using humic acid as a common natural organic matter. The experimental design was estimated by MINITAB software and the results was analyzed by the factorial analysis which suggest that the pH is the most significant factor affecting the removal process.

Treatment performance and microbial response to dibutyl phthalate contaminated wastewater in vertical flow constructed wetland mesocosms.

Phthalic acid esters (PAEs), especially dibutyl phthalate (DBP) pollution in the environment, have attracted worldwide attention. Four Phragmites australis-based, mesocosm-scale vertical flow constructed wetlands (VFCWs) with different hydraulic loading rates (HLRs) were operated for one year to study the removal efficiency and mechanisms of DBP in the reclaimed water. The average removal efficiencies for DBP were 93.77±3.27%, 94.9±2.60% and 97.0±3.00% in the VFCWs under HLRs of 0.33, 0.22 and 0.11m/d, respectively. DBP can be accumulated and degraded by wetland plants and its concentration in the roots (0.256-8.45mg/kg) were higher than in the leaves (0.243-0.482mg/kg). The concentrations of primary and secondary metabolites mono-n-butyl phthalate (MBP) and phthalic acid (PA) were 0.142-2.35mg/kg and 0.113-0.545mg/kg respectively in the plant tissues. The concentrations of DBP were 38.2-271μg/kg in the substrates. Mass balance for DBP indicates that the estimated plant uptake and substrate adsorption of total DBP is negligible. This suggests that biodegradation and other process are the primary pathways for DBP removal in VFCWs. The results of 16S rDNA and ITS rDNA high-throughput sequencing indicated that both bacterial and fungal community diversity decreased with the exposure of DBP. Janthinobacterium, Flavobacterium and Curvularia genera may be the main participants in the biodegradation of DBP in the CWs.

Effects of humic acid on the biodegradation of di-n-butyl phthalate in mollisol

Soil phthalic contamination has received more and more attention due to the widespread use of plastic mulching films. Humic acid (HA) is a natural antidote. The effects of HA on the biodegradation of dibutyl phthalate (DBP) in mollisol was investigated in this study. Through the calculation by bi-exponential model, the half-life of DBP was effectively shortened after adding HA, from 11.65 days to 3.36 days, and soil bulk density decreased. The enhancement mechanism for DBP removal by HA was analyzed by fluorescence spectrometry, two-dimensional FTIR correlation spectroscopy (2D-FTIR-COS) and PLFA analysis. Two major functional groups (aryl C–O and alkyl ester CO) were found at the binding site between DBP and HA. By mediating the transportation of DBP, HA could provide more time for soil microorganisms to degrade DBP. Meanwhile, HA effectively stabilized the mollisol microbial community composition and promote the growth of aerobic bacteria, which contributes to the degradation of DBP. The results are valuable for relieving DBP pollution caused by agricultural production and promoting sustainable use of mollisol.

Removal of Dibutyl Phthalate and Its Effects on Bacterial Communities in Lab-scale Constructed Wetlands

Removal of Dibutyl Phthalate and Its Effects on Bacterial Communities in Lab-scale Constructed Wetlands

Simultaneous remediation of As(III) and dibutyl phthalate (DBP) in soil by a manganese-oxidizing bacterium and its mechanisms

Soils are experiencing increasing pollution with arsenic (As) and phthalate esters (PAEs), which is threatening human health. In this study, the feasibility of simultaneous remediation of soil As(III) and a PAE, dibutyl phthalate (DBP), by a manganese-oxidizing bacterium (MnOB) was evaluated. As immobilization and DBP degradation were simultaneously enhanced by MnOB addition. The effects of initial concentrations of As(III), DBP, and Mn(II), and moisture content on the removal of As(III) and DBP were investigated. The results indicated that there was a competitive interaction between As(III) and DBP removal, and 40 mg/kg of Mn(II) dosage and 20%–30% soil moisture content were recommended for optimal and simultaneous removal of As(III) and DBP. Microbial community analysis revealed that community structure and diversity were not changed significantly by MnOB addition. Taken together, the findings from this study indicated that DBP was degraded primarily by microorganisms, whereas As(III) was removed largely by biogenic Mn oxides and immobilized by adsorption onto Mg/Fe oxides and/or formation of metal arsenate precipitates/co-precipitates. This study offers a novel and high-efficiency strategy to remediate the combined contamination of As and PAEs in soils.

Photocatalytic degradation performance and mechanism of dibutyl phthalate by graphene/TiO2 nanotube array photoelectrodes

Graphene loaded TiO2 nanotube array (GR/TNA) photoelectrodes were prepared by using anodization and electrodeposition approaches. The effects of different pH values, anions, bias potentials and electron acceptors on the photocatalytic activity of GR/TNA photoelectrodes in the degradation of dibutyl phthalate (DBP) were systematically investigated. Enhanced DBP removal ratio of 87.9% was achieved by GR/TNA photoelectrodes after 90 min of illumination. As a result, with the increase of initial pH values, the DBP removal ratio was also gradually increased. The addition of anions negatively affect the photocatalytic degradation of DBP by the order of NO3− > HCO3− > SO42− > Cl−. After applying a bias potential of +1.0 V, the highest DBP removal ratio of 98% was obtained. In addition, the presence of electron acceptors, KBrO3, K2S2O8 and H2O2, improved the photocatalytic activity of GR/TNA photoelectrodes. Furthermore, to better understand the underlying pathways in the photocatalytic degradation of DBP, the involved reactive species and produced intermediates were detected and analyzed. The major reactive species involved in this system were testified to be hydroxyl, superoxide radicals and holes by performing trapping experiments. The possible mechanism for the photocatalytic degradation of DBP was also proposed and discussed in detail.