Degradation Of Dimethyl Phthalate Research Articles

Study on the mechanism and degradation behavior of Encifer adhaerens DNM-S1 capturing dimethyl phthalate

The global concern surrounding pollution caused by phthalates is escalating, with dimethyl phthalate (DMP) emerging as one of the most prevalent contaminants within the phthalates (PAEs) category. Although the biodegradation of DMP is considered both safe and efficient, its underlying degradation mechanism is not yet fully elucidated, and the degradation performance can be somewhat inconsistent. To address this issue, our study isolated a DMP-degrading bacterium (DNM-S1) from a vegetable greenhouse. The resulting data revealed that DNM-S1 exhibited a remarkable degradation performance, successfully degrading 84.98% of a 2000 mg L−1 DMP solution within 72 h. Remarkably, it achieved complete degradation of a 50 mg L−1 DMP solution within just 3 h. DMP degradation by DNM-S1 was also found to be efficient even under low-temperature conditions (10 °C). Our research further indicates that DNM-S1 is capable of capturing DMP through the ester bond in the bacterium's cell wall fatty acids, forming hydrogen bonds through hydrophobic interactions. The DMP was then transported into the DNM-S1 protoplasm using an active transport mechanism. Interestingly, the secondary metabolites of DNM-S1 contained natural carotenoids, which could potentially counteract the damaging effects of PAEs on cell membrane permeability. In summary, these findings highlight the potential of DNM-S1 in addressing PAEs pollution and provide new insights into the metabolic mechanism of PAEs degradation.

Degradation of Dimethyl Phthalate and Diethyl Phthalate by Bacteria Isolated from Jazan, Saudi Arabia

P hthalate esters (PAEs) are commonly utilized in commercial, industrial, and medical applications. Various concentrations of PAEs have been detected in seawater samples and treated wastewater obtained from wastewater treatment plants in Saudi Arabia. Since these compounds pose adverse effects to human health, it is vital to develop efficient strategies to eliminate phthalate contamination from environments. In the present study, an enrichment technique was used to isolate phthalate-degrading bacteria from seawater and from activated sludge collected at Jazan Wastewater Treatment Plant, Saudi Arabia. Bacteria with the capability of degrading dimethyl phthalate (DMP) or diethyl phthalate (DEP) were isolated using minimum salt medium supplemented with these compounds as the sole carbon and energy source. High-performance liquid chromatography (HPLC) was utilized to evaluate the residual concentration of DMP and DEP. Using the 16S rRNA gene sequencing technique, the isolates with maximum DMP biodegradation activity were identified as Achromobacter sp. M1 and Pseudomonas sp. M2, while the isolates with maximum DEP biodegradation activity were identified as Pseudomonas sp. E2 and Pseudomonas sp. E3. The optimum bacterial growth was achieved at 30°C, pH 7.0, and 2% NaCl, except for Pseudomonas sp. E3, which demonstrated its maximum growth in the absence of NaCl. The highest biodegradation rate for all the bacterial strains (> 99.0%) was achieved at 30°C, pH 7.0, and up to 2% NaCl within 4 days. Concurrently, Pseudomonas sp. M2 and Pseudomonas sp. E2 exhibited remarkable degradation rates (97.5% and 56.7%, respectively) at 4% NaCl whereas Pseudomonas sp. E3 showed its highest DEP degradation (82.4%) after 4 days in the absence of NaCl. This study offers potential candidates, including Achromobacter sp. M1, Pseudomonas sp. M2, Pseudomonas sp. E2, and Pseudomonas sp. E3, for the proficient biodegradation of DMP and DEP.

Degradation of Dimethyl Phthalate by Heterogeneous Electro-Fenton Process Using Fe3O4-Doped Biomass Porous Carbon

Degradation of Dimethyl Phthalate by Heterogeneous Electro-Fenton Process Using Fe3O4-Doped Biomass Porous Carbon

Degradation of dimethyl phthalate by morphology controlled β-MnO2 activated peroxymonosulfate: The overlooked roles of high-valent manganese species

Activated peroxymonosulfate (PMS) processes have emerged as an efficient advanced oxidation process to eliminate refractory organic pollutants in water. This study synthesized a novel spherical manganese oxide catalyst (0.4KBr-β-MnO2) via a simple KBr-guided approach to activate PMS for degrading dimethyl phthalate (DMP). The 0.4KBr-β-MnO2/PMS system enhanced DMP degradation under different water quality conditions, exhibiting an ultrahigh and stable catalytic activity, outperforming equivalent quantities of pristine β-MnO2 by 8.5 times. Mn(V) was the dominant reactive species that was revealed by the generation of methyl phenyl sulfone from methyl phenyl sulfoxide oxidation. The selectivity of Mn(V) was demonstrated by the negligible inhibitory effects of Inorganic anions. Theoretical calculations confirmed that Mn (V) was more prone to attack the CO bond of the side chain of DMP. This study revealed the indispensable roles of high-valent manganese species in DMP degradation by the 0.4KBr-β-MnO2/PMS system. The findings could provide insight into effective PMS activation by Mn-based catalysts to efficiently degrade pollutants in water via the high-valent manganese species.

Novel fabrication of the recyclable Bi7O9I3/chitosan and BiOI/chitosan heterostructure with improved photocatalytic activity for degradation of dimethyl phthalate under visible light.

Among the bismuth oxyhalides, bismuth oxide has the shortest band gap and high absorption power in the visible light region. Dimethyl phthalate (DMP) has been identified as endocrine-disrupting plasticizer and emerging pollutant, which was selected as the target pollutant to evaluate the efficacy of the studied catalytic process. In this work, Bi7O9I3/chitosan and BiOI/chitosan were efficaciously synthesized by the hydrothermal process method. Characterizing prepared photocatalysts was done by employing transmission electron microscopy, X-ray diffraction, scanning electron microscopy energy-dispersive spectroscopy, and diffuse reflectance spectroscopy. For this study, the test design was performed using the Box-Behnken Design (BBD) method in which the variables of pH, Bi7O9I3/chitosan dose, and dimethyl phthalate concentration were examined for the catalytic removal of dimethyl phthalate in the presence of visible light. Our detected results disclosed that the order of efficiency in DMP removal was as follows: Bi7O9I3/chitosan > BiOI/chitosan > Bi7O9I3 > BiOI. Also, the maximum pseudo-first-order kinetic coefficient for Bi7O9I3/chitosan was 0.021 (min)-1. When the synthesized catalysts were exposed to visible light irradiation, the predominant active species were O2- and h+ for degradation of DMP. The study on the reuse of Bi7O9I3/chitosan showed that this catalyst could be reused 5 times without significant reduction in efficiency, which indicates the cost-effectiveness and environmental friendliness of using this catalyst.

Enhancement of the degradation efficiency of dimethyl phthalate by microwave-induced wet oxidation with lower energy consumption

Dimethyl phthalate, a common ingredient in the manufacture of plastics, is a typical persistent substance in the organic wastewater environment owing to its lipophilic and refractory properties. To achieve higher degradation of dimethyl phthalate, this study uses an experimentally constructed high-pressure resistant microwave-catalyzed experimental system, which can establish a coupling between the microwave and pressure fields in the wet oxidation process. Three types of catalysts are investigated for catalytic degradation, along with the effects of variables, such as reaction temperature, system pressure, and catalyst concentration, on the removal of dimethyl phthalate. Increasing the reaction temperature effectively increases the reaction rate constant. In addition, the COD content reduces from 4161.8 to 1710.5 mg/L within 5 min. Further, the energy flow and economy indices of the entire process are comprehensively analyzed. Finally, the analysis of the degradation intermediate and other characterization techniques reveals that the pollutant is degraded by ·OH.

Plasticizer phthalate esters degradation with a laccase from Trametes versicolor: effects of TEMPO used as a mediator and estrogenic activity removal.

Phthalate esters (PAEs) are toxic and persistent chemicals that are ubiquitous in the environment and have attracted worldwide attention due to their threats to the environment and human health. Dimethyl phthalate (DMP) is a relatively simple structure and one of the most observed PAEs in the environment. This study investigated the degradation of the DMP using Trametes versicolor laccase and its laccase-mediator systems. The degradation effect of laccase alone on DMP was poor, while the laccase-mediator systems can effectively enhance the degradation efficiency. Within 24h, 45% of DMP (25mg/L) was degraded in the presence of 0.8 U/mL laccase and 0.053mM 2, 2, 6, 6-tetramethylpiperidine-1-oxyl (TEMPO). A certain concentration (1mM) of metal ions Al3+, Cu2+ or Ca2+ can positively promote DMP degradation with the laccase-TEMPO system. Moreover, the structure of PAEs also had a great influence on the degradation efficiency. Higher degradation efficiencies were observed when incubating PAEs with short alkyl side chains by the laccase-TEMPO system compared to that with long alkyl side chains. Additionally, the branched-chain PAEs had a better degradation effect than the straight-chain. The estrogenic activity of the DMP solution after reaction was much smaller than that of the original solution. Finally, transformation products ortho-hydroxylated DMP and phthalic acid were identified by GC-MS and the possible degradation pathway was proposed. This study verifies the feasibility of the laccase-TEMPO system to degrade PAEs and provides a reference for exploring more potential value of laccase.

An oxidoreductase enzyme, fungal laccase immobilized on zeolitic imidazolate frameworks for the biocatalytic degradation of an endocrine-disrupting chemical, dimethyl phthalate

This study investigated a facile one-pot synthesis procedure of zeolitic imidazolate frameworks (ZIF) and laccase immobilization for use in the biodegradation of an endocrine-disrupting chemical (EDC), dimethyl phthalate (DMP). The as-synthesized Lac-ZIF’s characterization results revealed preserved crystallinity of the ZIF particles and lightly enzyme-coated decahedral particles. The immobilized laccase demonstrated enhanced temperature and storage stabilities for up to 65 ℃ and 20 d, respectively, for the DMP removal. While a reduced maximum velocity (Vmax) after the laccase immobilization (0.651–0.238 mg L−1 h−1) was observed, the Lac-ZIF presented a higher DMP removal efficiency (90.1%) compared to the free laccase (53.2%) within 4 h of contact time. Additionally, after 5 cycles of reuse, the Lac-ZIF retained a remarkable 95.2% efficiency and improved effectiveness in DMP decontamination from river water samples than the free laccase. Furthermore, the resulting DMP degradation metabolites were studied and revealed the production of relatively less toxic compounds after probable complete microbial mineralization. The study, therefore, demonstrates that Lac-ZIF has an admirable performance in the effective removal of phthalates from wastewater, making it a promising candidate for environmental remediation.

Activation of peroxymonosulfate by cow manure biochar@1T-MoS2 for enhancing degradation of dimethyl phthalate: Performance and mechanism

Introduction: Dimethyl phthalate (DMP) which has been widely detected in water is neurotoxic to humans and should be effectively eliminated. Persulfate-based advanced oxidation processes are considered to be reliable methods aiming at emerging contaminants degradation, while an efficient catalyst is urgently needed for the activation of the reaction. As a typical 2D material, 1T-MoS2 is expected to be applied to the activation of persulfate owing to its abundant active sites and excellent electrical conductivity. In practical applications, 1T-MoS2 has the phenomenon of reunion which affects the exposure of its catalytic sites.Methods: Therefore, in this study, we used waste cow manure as a raw material to prepare biochar and achieved high exposure of 1T-MoS2 activation sites by loading 1T-MoS2 onto the surface of cow manure biochar through hydrothermal synthesis. The prepared composite catalytic material CMB@1T-MoS2 was used to activate PMS for the degradation of DMP.Results: It was found that CMB@1T-MoS2 has better effect than CMB or 1T-MoS2 alone for the degradation of DMP, reaching 77.65% at pH = 3. Under alkaline conditions, the degradation rate of DMP was reduced due to the inhibition of the catalytic process. Among the different coexisting anions, HCO-3 interfered and inhibited the degradation process the most, leading to the lowest degradation rate of DMP with 42.45%.Discussion: The quenching experiments and EPR analysis showed that SO-4• and •OH were the main ROS in the CMB@1T-MoS2/PMS process. This study promotes the resourceful use of cow manure and is expected to provide a novel persulfate-based advanced oxidation process catalyzed by CMB@1T-MoS2 for the elimination of DMP in an aqueous environment.

Process optimization and kinetic study of biodegradation of dimethyl phthalate by KS2, a novel strain of Micrococcus sp.

The present study elucidates identification and characterization of dimethyl phthalate (DMP) degrading novel bacterial strain, Micrococcus sp. KS2, isolated from soil contaminated with municipal wastewater. Statistical designs were exercised to achieve optimum values of process parameters for DMP degradation by Micrococcus sp. KS2. The screening of the ten important parameters was performed by applying Plackett–Burman design, and it delivered three significant factors (pH, temperature, and DMP concentration). Further, response surface methodology involving central composite design (CCD) was implemented to examine mutual interactions among variables and achieve their optimal response. The predicted response indicated that maximum DMP degradation (99.67%) could be attained at pH 7.05, temperature 31.5 °C and DMP 289.19 mg/l. The strain KS2 was capable of degrading up to 1250 mg/l of DMP in batch mode and it was observed that oxygen was limiting factor in the DMP degradation. Kinetic modeling of DMP biodegradation indicated that Haldane model fitted well with the experimental data. During DMP degradation, monomethyl phthalate (MMP) and phthalic acid (PA) were identified as degradation metabolites. This study provides insight into DMP biodegradation process and proposes that Micrococcus sp. KS2 is a potential bacterial candidate to treat effluent containing DMP.

Tuned CuCr layered double hydroxide/carbon-based nanocomposites inducing sonophotocatalytic degradation of dimethyl phthalate

This study is the first to explore the possibility of utilizing CuCr LDH decorated on reduced graphene oxide (rGO) and graphene oxide (GO) as sonophotocatalysts for the degradation of dimethyl phthalate (DMP). CuCr LDH and its nanocomposites were successfully fabricated and characterized. Scanning electron microscopy (SEM) along with high-resolution transmission electron microscope (HRTEM) both evidenced the formation of randomly oriented nanosheet structures of CuCr LDH coupled with thin and folded sheets of GO and rGO. The impact of diverse processes on the degradation efficiency of DMP in the presence of the so-prepared catalysts was compared. Benefiting from the low bandgap and high specific surface area, the as-obtained CuCr LDH/rGO represented outstanding catalytic activity (100 %) toward 15 mg L−1 of DMP within 30 min when subjected to light and ultrasonic irradiations simultaneously. Radical quenching experiments and visual spectrophotometry using an O-phenylenediamine revealed the crucial role of hydroxyl radicals compared to holes and superoxide radicals. Overall, outcomes disclosed that CuCr LDH/rGO is a stable and proper sonophotocatalyst for environmental remediation.

Catalytic activation of hydrogen peroxide by Cr2AlC MAX phase under ultrasound waves for a treatment of water contaminated with organic pollutants

This study aims to investigate the sonocatalytic activation of hydrogen peroxide (H2O2) using Cr2AlC MAX phase prepared by the reactive sintering process. The hexagonal structure of the crystalline MAX phase was confirmed by X-ray diffraction. Moreover, the compacted layered structure of the MAX phase was observed via scanning electron microscopy and high-resolution transmission electron microscopy. Under the desired operating conditions, Cr2AlC MAX phase (0.75g/L) showed suitable potential to activate H2O2 (1mmol/L) under sonication, thereby allowing a considerable removal efficiency for various organic pollutants, including dimethyl phthalate (69.1%), rifampin (94.5%), hydroxychloroquine (100%), and acid blue 7 (91.5%) with initial concentration of 15mg/L within 120min of treatment. Kinetic analysis proved that the degradation reaction followed pseudo-first-order kinetics. Scavenging tests demonstrated that hydroxyl radicals and singlet oxygen were effective species during degradation. Furthermore, a probable mechanism for dimethyl phthalate degradation was suggested according to gas chromatography-mass spectroscopy and nuclear magnetic resonance analyses. The obtained results confirmed the capability of the triple Cr2AlC/H2O2/US process as a promising method for treating contaminated water.

Activation of peroxymonosulfate with cobalt embedded in layered δ-MnO2 for degradation of dimethyl phthalate: Mechanisms, degradation pathway, and DFT calculation

The sulfate radical-based advanced oxidation processes (SR-AOPs) offer huge potential for the removal of organic pollutants. In this study, Co(II)-intercalated δ-MnO2 (Co-δ-MnO2) catalyst was successfully prepared by a simple cation exchange reaction. The obtained Co-δ-MnO2 exhibited high catalytic performance for the removal of dimethyl phthalate (DMP) under the activation of peroxymonosulfate (PMS), with the degradation efficiency reaching 100% within 6 h. Experiments and theoretical calculations revealed that interlayer Co(II) provided unique active sites in Co-δ-MnO2. In addition, radical and non-radical pathways were confirmed to play a role in Co-δ-MnO2/PMS system. •OH, SO4• ̶, and 1O2 were identified to be the dominating reactive species in Co-δ-MnO2/PMS system. This study provided new insights into the design of catalysts and laid a foundation for developing modifiable layered heterogeneous catalysts.

3-D/3-D Z-Scheme Heterojunction Composite Formed by Marimo-like Bi2WO6 and Mammillaria-like ZnO for Expeditious Sunlight Photodegradation of Dimethyl Phthalate

In the present work, we assessed the photocatalytic performance of the new 3-D/3-D Z-scheme heterojunction composite for the degradation of dimethyl phthalate (DMP). The composite was composed by marimo-like Bi2WO6 and mammillaria-like ZnO which was named BWZ. The composite was successfully fabricated using a hydrothermal-precipitation method and analyzed via different characterization techniques. Under natural sunlight irradiation, the optimal composite with 20 wt% of Bi2WO6/ZnO (20-BWZ) exhibited a photodegradation rate constant of 0.0259 min−1, which reached 2.3 and 5.9-folds greater than those of pure ZnO (0.0112 min−1) and Bi2WO6 (0.0044 min−1), respectively. That was predominantly attributed to the formation of a Z-scheme photocatalytic system in the as-synthesized composite reduced the charge carrier recombination and accelerated the photoactivity. Transient photocurrent response and electrochemical impedance spectroscopy analyses were performed to confirm this conclusion. The reusability test indicated that the 20-BWZ had no significant deactivation after four runs, which inferred good stability of the as-prepared composite. Furthermore, the quenching test demonstrated that the photogenerated hole, superoxide anion radical and hydroxyl radical were all involved in the photodegradation of DMP, among which •OH was the principal reactive species. This work revealed that the as-prepared BWZ composites have great potential applications for the degradation of refractory pollutants in the environmental remediation field.

Indium-doped β-MnO2 catalyst for activation of peroxymonosulfate to generate singlet oxygen with complete selectivity

Singlet oxygen (1O2) has been regarded as an excellent active species for the effective degradation of pollutants. However, generating 1O2 with high selectivity still remains a significant challenge. Herein, 1O2 generation of 100% selectivity for peroxymonosulfate (PMS) activation was achieved by a strategy of indium-doped β-MnO2 catalyst, affording a dimethyl phthalate degradation rate of 93% within 180 min. Indium active sites served as the active center of the PMS adsorption, and the redox cycling of indium among different valances promoted PMS activation by breaking S–O bond. Density functional theory calculation results demonstrated that HSO5-could be easily adsorbed at indium site to generate 1O2 via effective electron transfer. The indium active sites and oxygen vacancies jointly regulated the PMS decomposition by a non-radical pathway with simultaneous 1O2 generation. This work developed a novel indium-doped β-MnO2 catalyst for complete selective generation of 1O2 for highly efficient degradation of pollutants.

Effect of Light and Heavy Rare Earth Doping on the Physical Structure of Bi2O2CO3 and Their Performance in Photocatalytic Degradation of Dimethyl Phthalate

In order to solve the problem of environmental health hazards caused by phthalate esters, a series of pure Bi2O2CO3 and light (La, Ce, Pr, Nd, Sm and Eu) and heavy (Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) rare earth-doped Bi2O2CO3 samples were prepared by hydrothermal method. The crystalline phase composition and physical structure of the samples calcined at 300 °C were studied, and we found that the rare earth ion doping promoted the transformation of Bi2O2CO3 to β-Bi2O3 crystalline phase, thus obtaining a mixed crystal phase photocatalyst constituted by rare earth-ion-doped Bi2O2CO3/β-Bi2O3. The Bi2O3/Bi2O2CO3 heterostructure had a lower band gap and more efficient charge transfer. The fabricated samples were applied to the photocatalytic degradation of dimethyl phthalate (DMP) under a 300 W tungsten lamp, and it was found that the rare earth ion doping enhanced the photocatalytic degradation activity of DMP, in which the heavy rare earth of Er-doped sample reached 78% degradation for DMP at 150 min of light illumination. In addition, the doping of rare earths resulted in a larger specific surface area and a stronger absorption of visible light. At the same time, the formation of Bi2O2CO3/β-Bi2O3 heterogeneous junction enhanced the separation efficiency of photogenerated electrons and holes.

Exploring simultaneous elimination of dimethyl phthalate and nitrogen by a novel constructed wetlands coupled with dielectric barrier discharge plasma

Dimethyl phthalate (DMP) contamination, as an emerging pollutant, has posed acute health risks to humans due to its potential disruption in reproductive function and endocrine system disorders. In this study, the dielectric barrier discharge (DBD) plasma and constructed wetlands (CWs) were coupled to explore the simultaneous enhancement of DMP and nitrogen removal. The results showed that the coupling DBD plasm and CWs obtained an efficient elimination of DMP (87.7–97.3%), and nitrogen removal was also improved simultaneously with higher removal of ammonia nitrogen (97.7–98.6%) and total nitrogen (TN, 22.6–40.6%). TN removal efficiency was promoted gradually by increasing the concentration of influent DMP due to the DMP decomposition into small molecules by DBD plasma, which could provide carbon source to promote denitrification for subsequent CWs. The DMP degradation processes in the coupling system were reflected by three-dimensional excitation emission matrix fluorescence spectrum and gas chromatograph-mass spectrometer, which indicated that DMP solution was activated in the DBD plasma and more organic by-products were produced. Additionally, monomethyl phthalate and phthalic acid were main degradation intermediate products of DMP. It indicated that coupling DBD plasma and CWs broke the carbon–oxygen single bond of DMP and converted it into less toxic compounds with less-refractory substances. This study provides assistant information on the application of the coupling DBD plasma and CWs technology for treating wastewater containing toxic and non-biodegradable contaminants.

Bisulfite-assisted surface Fenton-like degradation of dimethyl phthalate by ferrihydrite-H2O2 system

As a common plasticizer, phthalic acid esters (PAEs) have been widely employed to improve the flexibility and workability of polymetric materials, thus leading to their widespread distribution in soils and wastewater. Moreover, PAEs raised great public concerns due to their endocrine-disrupting effects, which could damage reproductive system and body development at low exposure dose. In the present study, a ferrihydrite-H2O2-bisulfite ternary system was developed to achieve efficient degradation of dimethyl phthalate (DMP). Our results showed that 86.6 % of total DMP could be removed within 240 min by the ferrihydrite-H2O2-bisulfite ternary system, in which the respective optimum concentration of ferrihydrite, H2O2 and bisulfite was set as 1.0 g/L, 5.0 mM and 2.0 mM. For comparison, negligible DMP removal was observed in the binary systems of ferrihydrite-H2O2, ferrihydrite-bisulfite and H2O2-bisulfite. Hydroxyl radical (•OH) was identified as the dominant reactive species for DMP degradation based on the results of electron paramagnetic resonance (EPR) analysis and free radicals quenching experiments. By complexing with iron species, bisulfite could accelerate the reduction of Fe(III) to Fe(II), thus increasing the generation of •OH by ∼4 times in the heterogeneous ferrihydrite-H2O2 system. Furthermore, ferrihydrite exhibited excellent recyclability without any modification as indicated by the negligible decrease in the catalytic degradation efficiency of DMP. Thus, in addition to efficient degradation of PAEs in wastewater, our study would shed light on the in-situ soil remediation technology on the basis of bisulfite-assisted heterogeneous Fenton-like reactions.

Synergistic effect of ferrous ion-activated hydrogen peroxide and persulfate on the degradation of phthalates in aquatic environments by non-target analysis

Oxidative degradation of most recalcitrant organics in the wastewater by exciting the oxidative potential and high efficacy of economic and environmental compatible oxidants is currently an extensively studied field of research. In this study, an efficient phthalate esters (PAEs) degradation method utilizing dual oxidants persulfate (PS) and hydrogen peroxide in the presence of ferrous ions was developed with high removal efficiency, small oxidant dosage and wide pH range. Compared with the degradation efficiency of single systems including Fe2+/ H2O2 (40 %), PS (24 %) and Fe2+/PS (49 %) for dimethyl phthalate (DMP) degradation, the combining PS and H2O2 activated by Fe2+ is more effective, with the removal efficiency of 95 %. The synergistic effect of PS and H2O2 in the Fe2+-containing system on PAEs degradation was reflected by the degradation products determined by non-target analysis of various oxidation processes. The results showed that the degradation of DMP in two single oxidant systems was dominated by aromatic compounds via dealkylation, hydroxyl addition and decarboxylation, while DMP in the PS/H2O2/FeSO4 system was mainly deeply oxidized to aliphatic molecules through further dearomatization, which was vulnerable for the mineralization of DMP to CO2 and H2O. In addition, the EPR technique combined with DMPO captured SO4•− and •OH signals in the presence of the same Fe2+ and oxidant dosage, revealing that a higher intensity of ·OH and SO4•− generated in the combined oxidative process resulted in a high removal of DMP. This work lays the groundwork for recalcitrant organics removal to apply synergistic activation mode in the AOPs system.

Enhanced photoelectrocatalytic performance for degradation of dimethyl phthalate over well-designed 3D hierarchical TiO2/Ti photoelectrode coupled dual heterojunctions

A novel A/R-TiO2 NSs/NRs photoelectrode was constructed through electrodeposition of anatase TiO2 nanosheets (A-TiO2 NSs) with highly exposed {001} facet onto the 1D upright rutile TiO2 nanorods (R-TiO2 NRs). At first, A/R-TiO2 NSs/NRs exhibited enhanced adsorption of dimethyl phthalate (DMP) due to the specific recognition between Lewis acid sites of {001} facet and Lewis basic DMP. NH3-TPD and Py-IR revealed that the Lewis acidity on the {001} facet of A-TiO2 NSs was much stronger than that of R-TiO2 NRs, demonstrating superior adsorption capacity to DMP. DFT theoretical calculations coupled with in-situ ATR-FTIR spectra were performed to investigate the binding adsorption behavior of DMP on A/R-TiO2 NSs/NRs. Secondly, the rapid separation of excited charges and strong oxidation of h+ were achieved by the synergistic effect of dual heterojunctions (A/R “phase heterojunction” and {111}/{110} “facet heterojunction”). The A/R-TiO2 NSs/NRs exhibited 100% degradation efficiency for the target pollutant DMP within 3 h, whose rate constant (k) was 18.02 × 10−3 min−1, 2.16 times that of pure R-TiO2 NRs. In real wastewater application, A/R-TiO2 NSs/NRs achieved 93.8% elimination of DMP during 4 h and preserved excellent stability after 5 cycles, promising a wide-range of applications in water environment remediation.