Dimethyl Phthalate Research Articles

Electro-Fenton approach in oxidative degradation of dimethyl phthalate - The treatment of aqueous leachate from landfills

Herein, the dimethyl phthalate (DMP) contamination, as an emerging pollutant, has been cost-effectively removed from landfill leachate through an advanced oxidation process, that is the electro-Fenton (EF) process. For this purpose, a quadratic polynomial model was developed via response surface methodology (RSM). Furthermore, the analysis of variance (ANOVA) was performed for evaluating the significance of the proposed assumptions. The actual removal rate of 99.1% was obtained with optimal values of 4 mg L−1 of initial DMP concentration, 50 mM Na2SO4, 600 μL L−1 H2O2, 8-minute electrolytic time, solution pH 3 and 6 mA cm−2 current density for the process variables and was consistent with the expected 99.6% removal rate. Satisfactory correlation coefficients were obtained, and a non-significant value of 0.0618 for model mismatch confirmed that the proposed model is extremely important and can successfully predict the effectiveness of DMP removal. The kinetics of the process and the effect of the presence of some radical scavengers were studied to understand the exact mechanism of DMP degradation. Therefore, it was observed that the reaction of hydroxyl radicals with DMPs followed the first-order kinetics model. Moreover, it was established that the optimal ratio of H2O2/Fe2+ mole was 1.6 and the electricity consumption was 0.157 kWh m−3. The elaborated treatment model used to remove DMP from landfill leachate showed that DMP contamination was effectively removed with a 95.6% removal efficiency in the investigating process.

Environmentally relevant mixtures of phthalates and phthalate metabolites differentially alter the cell cycle and apoptosis in mouse neonatal ovaries†.

Phthalates are a group of chemicals used as additives in various consumer products, medical equipment, and personal care products. Phthalates and their metabolites are consistently detected in humans, indicating widespread and continuous exposure to multiple phthalates. Thus, environmentally relevant mixtures of phthalates and phthalate metabolites were investigated to determine the effects of phthalates on the function of the ovary during the neonatal period of development. Neonatal ovaries from CD-1 mice were cultured with dimethyl sulphoxide (DMSO; vehicle control), phthalate mixture (0.1-100μg/mL), or phthalate metabolite mixture (0.1-100μg/mL). The phthalate mixture was composed of 35% diethyl phthalate, 21% di(2-ethylhexyl) phthalate, 15% dibutyl phthalate, 15% diisononyl phthalate, 8% diisobutyl phthalate, and 5% benzylbutyl phthalate. The phthalate metabolite mixture was composed of 37% monoethyl phthalate, 19% mono(2-ethylhexyl) phthalate, 15% monobutyl phthalate, 10% monoisononyl phthalate, 10% monoisobutyl phthalate, and 8% monobenzyl phthalate. After 96h of culture, ovaries were harvested for histological analysis of folliculogenesis, gene expression analysis of cell cycle and apoptosis regulators, and immune staining for cell proliferation and apoptosis. The metabolite mixture significantly decreased the number and percentage of abnormal follicles (100μg/mL) compared to controls. The metabolite mixture also significantly increased the expression of cell cycle inhibitors (100μg/mL) and the antiapoptotic factor Bcl2l10 (10μg/mL) compared to controls. The phthalate mixture did not significantly alter gene expression or follicle counts, but ovaries exposed to the phthalate mixture (0.1μg/mL) exhibited marginally significantly increased apoptosis as revealed by DNA fragmentation staining. Overall, these data show that parent phthalates and phthalate metabolites differentially impact ovarian function.

Water stable SiO2-coated Fe-MOF-74 for aqueous dimethyl phthalate degradation in PS activated medium

The poor water stability of metal-organic frameworks (MOFs) significantly hindered their catalytic application in advanced oxidation system. A protective outer layer was an effective strategy to solve this problem. However, the commonly used coating techniques are too complicated or too difficult to accurately control, thus, the applicability was relatively low. In this study, a water stable MOF core-SiO2 shell nanomaterial (Fe-MOF-74@SiO2) was synthesized by a facile hydrothermal method, and applied to activate persulfate (PS) for dimethyl phthalate (DMP) degradation. The catalyst water stability and DMP degradation in the system were investigated, suggesting that the SiO2-coated catalyst was more stable and exhibited higher DMP degradation efficiency over the pure MOF. It was found that pH had negligible effects on Fe-MOF-74@SiO2 + PS system, while, higher temperature facilitated the degradation of DMP. The activation mechanism was studied by quenching experiments combined with electron paramagnetic resonance, indicating that SO4⋅− played a major role in the activation of PS with Fe-MOF-74@SiO2 for DMP removal, while ⋅OH also involved in the catalytic process. Finally, possible DMP degradation pathways were proposed. These findings indicated that the core-shell structured Fe-MOF-74@SiO2 showed promise for DMP degradation by PS advanced oxidation system.

Contaminant occurrence, mobility and ecological risk assessment of phthalate esters in the sediment-water system of the Hangzhou Bay

The pollution characteristics, spatiotemporal variation, sediment–water partitioning, and potential ecological risk assessment of phthalate esters (PAEs) in the sediment–seawater system of the Hangzhou Bay (HZB) in summer and autumn were researched. The sum of the concentrations of the 10 PAEs in seawater ranges from 7305 ng/L to 22,861 ng/L in summer and from 8100 ng/L to 33,329 ng/L in autumn, with mean values of 15,567 ± 4390 and 17,884 ± 6850 ng/L, respectively. The Σ16PAEs in the sediments are between 118 and 5888 μg/kg and 145 and 4746 μg/kg in summer and autumn, respectively. The level of PAEs in seawater varies with the seasons, but it is relatively stable in the sediments. Di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DnBP), and diisobutyl phthalate (DiBP) are the predominant PAE congeners in the HZB. The DnBP and DiBP concentrations in seawater are greater than the DEHP concentration, which is the opposite in the sediments. The sediment–seawater equilibrium distribution study indicates that the PAEs with medium molecular weights, such as DiBP, butyl benzyl phthalate, and DnBP, are near dynamic equilibrium in the sediment–seawater system; PAEs with high molecular weights (e.g., di-n-octyl phthalate and DEHP) tend to transfer from water to the sediments; and PAEs with low molecular weights (e.g., dimethyl phthalate, diethyl phthalate, and diamyl phthalate) tend to spread to seawater. The risk assessment results in seawater indicate that DEHP and DiBP might pose high potential risks to sensitive organisms, and DnBP might exhibit medium ecological risks. In the sediment, DiBP might display a high potential risk to fish, and the potential risk of DEHP is high in several sites.

Spatial distribution, historical trend, and ecological risk assessment of phthalate esters in sediment from Taihu Lake, China.

In this study, the distribution of phthalate esters (PAEs) in twenty surface sediment and five core sediment samples in Taihu Lake, China, was investigated, and their ecological risks were assessed. Of the 10 PAE congeners, five PAEs including diethyl phthalate (DEP), dimethyl phthalate (DMP), di-n-butyl phthalate (DBP), di-iso-butyl phthalate (DIBP), and bis(2-ethylhexyl) phthalate (DEHP) were identified and quantified, and the rest 5 PAEs were below the limits of quantification. The concentrations of the total PAEs (ΣPAEs) in surface sediments and core sediments varied from 1.12 × 103 to 18.71 × 103 ng/g and 0.23 × 103 to 5.22 × 103 ng/g, respectively. The dominant PAEs were DBP and DIBP, contributing 85.90% to the ΣPAEs. Overall, the highest concentrations of ΣPAEs occurred in northern lake, followed by eastern lake and western lake, and southern lake was the least polluted area. The spatial distribution of ΣPAEs in sediments showed that the PAE distribution pattern was influenced by the riverside environment. The historical trend of the past 100 years was reconstructed in the core sediment via a 210Pb dating technique. The vertical profile of the PAE congeners indicated that concentrations of PAEs started to increase since the 1990s in northern core sediments. It was estimated that the inventories of ΣPAEs in Taihu Lake was 4868.01 t. The potential ecological risk assessment by hazard quotient (HQ) method revealed that DBP posed a moderate risk due to its relatively high concentrations, with DIBP posed a low risk, while DEP, DMP, and DEHP exhibited no risk to the aquatic system.

Selectively photoelectrocatalytic reduction of oxygen to hydroxyl radical and singlet oxygen: Mechanism and validation in coal wastewater

The fine-tuning of generating hydroxyl radical (OH) and singlet oxygen (1O2) was firstly proposed via the selectively photoelectrochemical (PE) reduction of oxygen with Cu-coordinated carbon-nitride-electrode (CuCN). Complete removal efficiency and trace Cu leaching (<0.01 ppm) were achieved during treatment of dimethyl phthalate and atrazine, which were mainly oxidized by OH and 1O2, respectively. Besides, no toxic intermediates was detected in the whole degradation process. The overall oxygen reduction pathway in PE system was demonstrated by electron paramagnetic resonance measurements and quenching tests. The valence band position of CuCN was designed to be more negative (−1.5 VSHE) for favoring the photocatalytic oxygen reduction. Specifically, Cu-N2-C as active sites optimized the Gibbs free energy of intermediate *OOH (ΔG*OOH = 3.99 eV) to improve the reactivity of two-electron oxygen reduction. The CuCN/photoelectrochemical system is applied for treatment of coal water slurry gasification (CWS) wastewater with high concentration of salt. The TOC of CWS was successfully decreased from 127 to 1.9 mg·L−1 in 3 h with a low specific energy consumption of 0.024−0.05 kW·h·g−1·TOC−1. The treated CWS wastewater can be used for recovery and utilization of salt as chemical raw materials. This work highlights the important role of synergistic photo-electro-catalytic effect in regulating the generation of active oxygen species via oxygen reduction pathway, which can be a promising way especially for salinity coal wastewater remediation.

The standard thermochemical properties of the p-Benzylphenol and Dimethyl phthalate, and their temperature dependencies

In the present work, the standard thermochemical properties of the p-Benzylphenol and dimethyl phthalate are determined using the results of B3LYP/6–311++G(d,p), M06-2X/6-311++G(d,p) and RO/CBS-4M calculations. The consistent values of the standard enthalpies of formation of these compounds are determined using the correction dependencies, as well as using the thermochemistry of the homodesmotic reactions. The calculated values of ΔfHo298.15(Dimethyl phthalate) agree with its experimental value, reported previously. At the same time, the calculated values of ΔfHo298.15(p-Benzylphenol) are significantly lower its reported value. The values of the standard entropies of these compounds, as well as the temperature dependencies of their thermochemical properties, are calculated for the first time in the present work.

The Assessment of the Sewage and Sludge Contamination by Phthalate Acid Esters (PAEs) in Eastern Europe Countries

Phthalate acid esters (PAEs) are widely used as raw materials for industries that are well known for their environmental contamination and toxicological effects as “endocrine disruptors”. The determining of PAE contamination was based on analysis of dimethyl phthalate (DMP), diethyl phthalate (DEP), dipropyl phthalate (DPP), dibutyl phthalate (DBP), diisobutyl phthalate (DiBP), dicyclohexyl phthalate (DCHP) and di(2-ethylhexyl) phthalate (DEHP) in wastewater and sediment samples collected from city sewer systems of Lithuania and Poland, and Denmark for comparison. The potential PAE sources as well as their concentrations in the wastewater were analyzed and discussed. The intention of the study was to determine the level and key sources of pollution by phthalates in some Eastern European countries and to reveal the successful managerial actions to minimize PAEs taken by Denmark. Water and sludge samples were collected in 2019–2020 and analyzed by gas chromatography-mass spectrometry. The highest contamination with phthalates in Lithuania can be attributed to DEHP: up to 63% of total PAEs in water samples and up to 94% of total PAEs in sludge samples, which are primarily used as additive compounds to plastics but do not react with them and are gradually released into the environment. However, in water samples in Poland, the highest concentration belonged to DMP—up to 210 μg/L, while the share of DEHP reached 15 μg/L. The concentrations of priority phthalate esters in the water samples reached up to 159 μg/L (DEHP) in Lithuania and up to 1.2 μg/L (DEHP) in Denmark. The biggest DEHP concentrations obtained in the sediment samples were 95 mg/kg in Lithuania and up to 6.6 mg/kg in Denmark. The dominant compounds of PAEs in water samples of Lithuania were DEHP &gt; DEP &gt; DiBP &gt; DBP &gt; DMP. DPP and DCHP concentrations were less than 0.05 μg/L. However, the distribution of PAEs in the water samples from Poland was as follows: DMP &gt; DEHP &gt; DEP &gt; DBP, and DiBP, as well as DPP and DCHP, concentrations were less than 0.05 μg/L. Further studies are recommended for adequate monitoring of phthalates in wastewater and sludge in order to reduce or/and predict phthalates’ potential risk to hydrobiots and human health.

Comparative Analysis of Neurotoxicity of Six Phthalates in Zebrafish Embryos.

The effects and underlying mechanisms of phthalates on neurotoxicity remain unclear as compared with the potentials of these substances as endocrine disruptors. The locomotor activities of zebrafish embryos were investigated upon exposure to six phthalates: dimethyl phthalate (DMP), diethyl phthalate (DEP), benzyl butyl phthalate (BBzP), di-2-ethylhexyl phthalate (DEHP), di-n-octyl phthalate (DnOP), and diisononyl phthalate (DiNP). Moreover, changes in fluorescence intensity in the green fluorescent protein (GFP) transgenic (Tg) lines Tg(HuC:eGFP), Tg(sox10:eGFP), and Tg(mbp:GFP) were measured after exposure to six phthalates, and changes in the expression profiles of genes involved in the cholinergic (ache) and dopaminergic systems (dat, th, and drd1b) were assessed. Exposure to BBzP, DEHP, and DiNP affected larval behaviors, whereas exposure to DMP, DEP, and DnOP revealed no alterations. A reduced expression of Tg(HuC:eGFP) was observed upon exposure to BBzP, DEHP, and DiNP. The expression of Tg(sox10:eGFP) and Tg(mbp:GFP) was reduced only in response to BBzP and DiNP, respectively. Further, exposure to DiNP upregulated ache and drd1b. The upregulation of ache and downregulation of drd1b was observed in DEHP-exposed groups. Exposure to BBzP suppressed th expression. These observations indicate that exposure to phthalates impaired embryogenesis of the neurological system and neurochemicals in zebrafish embryos, although the detailed mechanisms varied among the individual phthalates. Further mechanistic studies are needed to better understand the causality between phthalate exposure and neurotoxicity.

BaTiO3 SERS substrates for Dimethyl phthalate detection

The surface spectroscopic technique, surface-enhanced Raman spectroscopy (SERS) is a powerful analytical tool for chemical and biological sensing applications. Noble metals like gold, silver, etc. have been most commonly used as SERS materials since their surface plasmon resonance can enhance the local electromagnetic field and amplify the SERS signals. However, the basic issue that has limited its use is the difficulty involved in producing uniform, sensitive, and reproducible efficient SERS substrates. Recently serious efforts have been focused on investigating the Raman activity of semiconductor nanomaterials with tunable chemical and physical properties, high selectivity, and sensitivity. In this work, nanosized phase pure Tetragonal structured Barium Titanate (BT) has been synthesized by modified sol–gel route. The bandgap of the perovskite BaTiO3 is 3.2 eV, determined from the diffused reflectance spectra. The optical phonon modes obtained from the Raman spectra again confirms the formation of the tetragonal Barium Titanate. To check the SERS activity of BT, Dimethyl phthalate (DMP) molecules were used as probe molecules. The BT substrates show great enhancement in the Raman spectra, many fingerprint Raman bands of Dimethyl phthalate were observed from the BT substrates. This enhanced SERS activity of BT can be explained based on the charge transfer resonance. The results demonstrate that noble metal-free Barium Titanate has great potential as a highly sensitive substrate for the detection of trace Dimethyl Phthalate.

Surface blocking of azolla modified copper electrode for trace determination of phthalic acid esters as the molecular barricades by differential pulse voltammetry: response surface modelling optimized biosensor.

In this work, a sensitive and efficient voltammetric biosensor was introduced for differential pulse voltammetric (DPV) determination of some phthalic acid esters (PAEs) including dibutyl phthalate (DBP), dimethyl phthalate (DMP), di(2-ethylhexyl)phthalate (DEHP) and dicyclohexyl phthalate (DCHP) in aqueous solutions. Briefly, the surface of a copper electrode was modified by azolla paste prepared using azolla powder and electroencephalography gel (EEG). The modified surface was characterized by electrochemical impedance spectroscopy (EIS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET) analysis and energy dispersive X-ray (EDX) methods. Determination of PAEs was conducted based on their blocking effect on the electrode surface for ferrous ion oxidation. The central composite design (CCD) was conducted to optimize the effects of four experimental parameters including the concentration of Fe2+ ions (CFe2+) and supporting electrolyte (Csup. elec), solution pH and modifier/gel mass ratio on the decrease in the anodic peak current of ferrous ions as the response. Predicted optimal conditions (CFe2+= 319 μM, Csup. elec= 0.125 M, pH = 7.52 and modifier/gel mass ratio = 0.19) were validated by experimental checking which resulted in an error of 1.453%. At the optimum conditions, linear relationships were found between the DPV responses and PAEs concentrations and the limit of detection (LOD) and limit of quantification (LOQ) values were in the ranges of 0.2–0.4 μg L−1 and 0.5–1.0 μg L−1, respectively. Good recovery percentages ranging from 97.3 to 100.3% with RSD < 3.2% suggested the proposed method for efficient, accurate and quick determination of PAEs in real water samples.

Phase equilibrium and dielectric relaxation in mixture of 5CB with dilute dimethyl phthalate: effect of coupling between orientation and composition fluctuations on molecular dynamics in isotropic one-phase state.

Phase equilibrium and dielectric relaxation were examined for mixtures of liquid-crystalline (LC)-forming 4-cyano-4'-pentylbiphenyl (5CB) with dilute dimethyl phthalate (DMP). The mixtures were in an isotropic one-phase state at high temperatures T but were separated into nematic and isotropic phases at low T < TIN (isotropic-to-nematic transition temperature), and the isotropic phase disappeared and a nematic one-phase state was realized on a further decrease of T below another transition temperature . These TIN and data (phase diagram) were described considerably well by a simple model of free energy contributed from a Flory-Huggins type mixing entropy (no enthalpic contribution) and a Landau-de Gennes type nematic interaction. This success of the model, not expected for ordinary (not LC-forming) components exhibiting enthalpically-driven phase separation, suggested that the phase separation in the DMP/5CB mixtures was triggered by the nematic transition of 5CB (possibly governed by the packing entropy) and thus the orientation fluctuation of 5CB molecules was coupled with the composition fluctuation. This coupling was expected to affect the dielectric relaxation detecting the rotational dynamics of 5CB molecules, the major component in the mixtures. This expectation was examined for a representative mixture having the DMP content of wDMP = 3.1 wt% and TIN ≅ 27.0 °C. In a high-T asymptote (T > TIN + 10 °C), the dielectric relaxation of this mixture was close to that of pure 5CB, which suggested no significant effect of the above coupling on 5CB dynamics in the mixture at such high T. Nevertheless, in a significantly wide range of T between TIN and TIN + 10 °C, the dielectric relaxation time τε of the isotropic one-phase mixture increased on cooling much more significantly compared to τε in that high-T asymptote. The kinematic viscosity ν of the mixture exhibited a qualitatively similar increase in the same range of T, but this increase was weaker than that of τε. This difference between the dielectric τε and the rheological ν was attributed to coupling of the orientation and the composition fluctuations mentioned above. Namely, the composition fluctuation enhances the orientation fluctuation in the mixture thereby providing τε (reflecting the orientation fluctuation) with an extra increase. Pure 5CB exhibited similar increases of τε and ν (stronger for the former) but only in a close vicinity of (within 2-3 °C), because the orientation fluctuation in pure 5CB is coupled with the density fluctuation, not with the composition fluctuation being absent in the pure 5CB system. This behavior of pure 5CB in turn suggests an importance of the coupling of orientation and composition fluctuations in the mixture.

Vortex-assisted Dispersive Solid-phase Extraction Using Schiff-base Ligand Anchored Nanomagnetic Iron Oxide for Preconcentration of Phthalate Esters and Determination by Gas Chromatography and Flame Ionization Detector.

Phthalate esters are synthetic chemicals that are widely used in plastic industries as plasticizer. They are harmful to humans and could be carcinogenic. In this research, a new nanosorbent was prepared via a Schiff-base reaction between p-dimethylaminobenzaldehyde and Fe3O4@SiO2-NH2 nanoparticles. A characterization of the sorbent was performed by Fourier-transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, and energy-dispersive spectroscopy. A modified nanosorbent has a core shell structure, and shows a great tendency towards the sorption of phthalate esters. Hence, it was utilized for the dispersive solid-phase extraction of six phthalate esters and determination by gas chromatography-flame ionization detection. Several variables, such as the pH, sorbent amount, salt effects, extraction and desorption time, extraction solvent type and volume, were investigated to establish the optimal conditions. Calibration graphs were linear in the range of 1.0 - 150.0 μg L-1 for dimethyl phthalate, bis-(2-ethylhexyl) phthalate, di-n-octyl phthalate and 0.1 - 200.0 μg L-1 for diethyl phthalate, di-n-butyl phthalate and butyl benzyl phthalate, respectively. The obtained limits of detections (S/N = 3) were in the range of 0.02 - 0.31 μg L-1. Application of the method for the enrichment and determination of phthalate esters in mineral water, natural low fat yogurt and sodium chloride infusion (0.9%, w/v) was investigated.

Plastic toy soldiers, a lost battle? – an analytical perspective

The conservation and preservation of museum collections requires a detailed understanding of their constituent materials which are often natural, synthetic or semi-synthetic polymers. The use of a wide variety of instrumental techniques can give an extraordinary amount of quality information, by delivering complementary data regarding composition and structure. This study was triggered by the Oporto Military Museum (Museu Militar do Porto) conservators who observed that a set of plastic toy soldiers dating back to the middle of the 20th century from the museum exhibition started to present severe and accelerated degradation process. With this is mind, the authors envisaged a methodology for the characterisation of these soldier toys that compromised elemental, structural and morphologic analysis, to allow the identification of polymers, their additives, and the degradation products. The methodology comprised stereoscopic microscopy and VP-SEM-EDS to recognize the micromorphology, ATR-FTIR to identify the polymer, 1H and 13C NMR to identify their additives, and micro-XRD to identify degradation products with a crystal structure. With this complementary analytical approach the composition of the toy soldiers was identified as being made of cellulose acetate plastic with triphenyl phosphate and dimethyl phthalate as major additives, and crystallyne efflorescence of triphenyl phosphate were identified as a degradation product. This methodology shows to be very adequate for a detailed characterization of plastic artefacts in museum environments.

Highly efficient removal mechanism of dimethyl phthalate over an economical 3D {001}TiO2/Ti photoelectrode with enhanced photoelectrocatalytic activity and long service life

Constructing highly efficient and economical photoelectrodes for dimethyl phthalate (DMP) degradation had been regarded as an encouraging strategy on environmental remediation. The 3D {001}TiO2/Ti photoelectrode was prepared via in situ growth of TiO2 microspheres with near 100 % {001} facets on Ti mesh, conducive to promoted active site supply and pohotogenerated charge separation. Compared with anatase TiO2/Ti, the DMP degradation efficiency over 3D {001}TiO2/Ti (near 100 %) improved by 8.8 times, and its TOC removal achieved 89.4 %. The 3D {001}TiO2/Ti demonstrated outstanding stability with removal rate of 97.7 % even after eight cycles. The effects of various influence factors such as applied bias and coexisting ions on DMP degradation were studied for practical applications. A referable mineralization mechanism, including three possible degradation pathways of DMP, was put forward as well based on 4 kinds of new-discovered compounds.

Integrating modeling and experimental method for narrowing the optimum phase composition in P25 photocatalyst for typical aromatic pollutants degradation

• The optimum anatase/rutile ratio for typical pollutants was facilely quantified. • The optimal W R of the six pollutants were in a narrow interval of 34.7%–38.4%. • The k depends on energy gap, photoluminescence intensity, and their interaction. • The k of different materials has little correlation with the BET area and groups. The apparent rate constant k of the photocatalytic reaction of typical aromatic pollutants, i.e., dyestuff (rhodamine B [RhB]), phenol (bisphenol A [BPA]), organic chloride (4-chlorophenol [4-CP]), drug (carbamazepine [CBZ]), antibiotics (tetracycline [TC]), and endocrine contaminants (dimethyl phthalate [DMP]), with TiO 2 at different ratios of rutile (W R ) was experimentally obtained. The modelling results between k and W R show that the optimal W R of the six pollutants were in a narrow interval of [0.347, 0.384] by LogNormal model. The two-factor interaction (2FI) and Linear model between the kinetic k value and the photocatalytic performance parameters were established. The Pareto analysis results show that Brunauer–Emmett–Teller (BET) specific surface (A) has little effect on the photocatalytic system, and the most important parameter is the interaction between Energy gap (Eg) and Photoluminescence (PL) intensity (B-C) that has a positive effect on photocatalytic reaction kinetics. The single-factor Eg (B) and PL intensity (C) have negative effects on UV photocatalytic reaction kinetics. This work can help narrow the range of the optimal W R of P25-TiO 2 for emerging organic pollutants.

Study of functionality of polymer films by dense electron beams

Methodology of using megavolt electrons for investigation of the functionality of thin polymer films of polycyanurates (PCN) is described. The relevance of research is determined by the prospects of using films as a functional basis for improvement of track-etched technologies of nanoporous nuclear filters, where ionizing radiation is used in most of technological stages of their production. Functionality control is the main criterion for the qualification of films on the suitability for production of nuclear filters on their base. Development of megavolt electrons radiation methods is promising for monitoring the functionality of filters. Radiation technologies are universal and able to provide maximum information content on investigations of the characteristics of materials to qualify them for suitability of practical use. To control the functionality of the films, the methodology for research and testing of thin polymer films using powerful electron beams of 1-2 MeV has been developed. The features of these methods and the results of their application at the control of functionality and for the qualification of the films based on crosslinked polycyanurates, synthesized by in situ polycyclotrimerization of dicyanate ester of bisphenol E in the presence of dimethylphthalate (DMPh) of the composition PCN/DMPh=70/30 wt.%, on the suitability for production of nanoporous track membranes are discussed. Key words: electron beams, nuclear membranes, thermostable polycyanurates, radiation stability, functional testing.

Enhancing PPCPs Removal and Membrane Fouling Control of Ultrafiltration Membrane by UiO-66@Fe3O4@UiO-66

Pharmaceuticals and personal care products (PPCPs) adsorption and membrane fouling control were realized by a polyvinylidene fluoride (PVDF) membrane loaded with multifunctional metal-organic frameworks (MOFs) in this study. During adsorption, the multifunctional MOFs UiO-66@Fe3O4@UiO-66 in the mixed-matrix membrane (MMMs) could adsorb two typical PPCPs, salicylic acid (SA), and dimethyl phthalate (DMP), efficiently. In the membrane catalytic regeneration process, Fe3O4 in UiO-66@Fe3O4@UiO-66 could catalyze H2O2 to generate hydroxyl radicals (HO·), coupling MOFs/PVDF adsorption capacity regeneration and membrane cleaning. The results show that 10%MOFs/PVDF exhibits the highest adsorption efficiency for 0.1 mmol·L-1 SA and DMP under neutral conditions, and the removal rate reached 64.2% and 46.1%, respectively. Additionally, the pure water flux and membrane adsorption capacity of 10%MOFs/PVDF were able to recover about 91.8% and 94.2%, respectively, using 5 mmol·L-1 H2O2. In this research, the main characteristic of MOFs/PVDF is coupling of the membrane adsorption capacity regeneration and membrane fouling control process. This provides new ideas for the removal of PPCPs and the improvement of membrane anti-fouling performance during the deep purification of secondary effluent.

Construction of crystal defect sites in UiO-66 for adsorption of dimethyl phthalate and phthalic acid

The influence of constructed crystal defect sites in the metal-organic framework on the adsorptive removal of phthalic acid and dimethyl phthalate from aqueous solution has been investigated by etching UiO-66 with three monocarboxylic acids (MAs), including acetic acid (AA), trifluoroacetic acid (TFA) and trichloroacetic acid (TCA). The incomplete replacement of bridging ligands in UiO-66s by MAs, leading to the departure of partial ligands and metal clusters to create mesopores in metal organic frameworks, was determined by thermogravimetric analysis (TGA), nuclear magnetic resonance ( 1 H NMR) and N 2 adsorption-desorption. The results showed that mediate defect would increase the specific surface area and introduce mesopores to some extent, and the crystal structure was gradually destroyed as the excess concentration of MAs. Among UiO-66 samples, the UiO-66 etched by AA with concentration of 1.6 mol/L (UiO-66-1.6AA) had the highest specific surface area while the UiO-66-0.2TCA had the largest pore volume, which significantly enhanced the adsorption capacity for DMP and PA (18.05% up of PA and 41.59% up of DMP to UiO-66) respectively. The experimental data followed the pseudo-first-order kinetic and Langmuir model. In addition, regeneration study showed that the adsorption capacity of PA and DMP on UiO-66-0.2TCA and UiO-66-1.6AA can still remain over 83 and 90% after five cycles, respectively. The crystal defect sites introduction of mesopores by etching method would be an effective strategy to adsorptive removal of organic pollutants in aqueous solution. • UiO-66 was etched by acetic acid, trifluoroacetic acid and trichloroacetic acid. • Etching shaped hierarchical pore structure in UiO-66. • Defective sites had various influence on adsorption capacity of PA and DMP. • Etching method significantly enhanced adsorption for molecules of different sizes.

New insights into tailoring polyamide structure for fabricating highly permeable reverse osmosis membranes

Herein, plasticizer-assisted interfacial polymerization was developed to fabricate thin-film composite (TFC) reverse osmosis (RO) membranes with improved water permeability and comparable salt selectivity. Three representative phthalate acid esters, including dimethyl phthalate (DMP), dibutyl phthalate (DBP), and dioctyl phthalate (DOP), served as the plasticizer. FTIR results revealed that the introduction of plasticizers disrupted original amide-amide bonding between polyamide chains, converting polyamide structure from stiff to flexible, thus significantly promoting water diffusion efficiency through the polyamide matrix. Besides, the presence of plasticizers led to the creation of more voids in the polyamide layer, where water transport resistance was relatively low. Specifically, with the addition of 0.6 wt% DMP, water flux enhanced from 19.1 L m−2 h−1 of the virgin membrane to 72.5 L m−2 h−1, with NaCl rejection declining from 99.3% to 98.3%. And 0.6 wt% DBP-modified membrane showed water flux of 44.0 L m−2 h−1 and NaCl rejection of 98.9%. It was interesting to discover that DOP possessed the poorest plasticizing capacity, which contradicted the traditional cognition that DOP is one of the most resultful plasticizers for polymers. We believed it was the sizable alkyl moieties in DOP that suppressed the interaction between DOP molecules and polyamide chains.