Removal of phthalates from aqueous solution by semiconductor photocatalysis: A review

Structure-dependent degradation of phthalate esters with persulfate oxidation activated by thermal in soil

Phthalate esters (PAEs) have become one of the most concerned emerging organic pollutants in the world, due to the toxicity to human health, and hard to remove it efficiently. In this study, the degradation performance of DBP and DEHP in the soil by water bath heating activated sodium persulfate (PS) method under different factors were studied, in which the degradation rate of DBP and DEHP were improved with the increasing of temperature, PS concentration and water/soil ratio, and higher diffusion efficiency treatments methods, due to the improved mass transfer from organic phase to aqueous media. However, the degradation rate of DEHP was much lower than that of DBP, because DEHP in the soil was more difficult to contact with SO4•- for reaction on soil surface, and the degradation rate of PAEs in soil was significantly lower than that in water. Redundancy analysis of degradation rate of DBP and DEHP in water demonstrated that the key factors that determine the degradation rate is time for DBP, and cosolvent dosage for DEHP, indicating that the solubility and diffusion rate of PAEs from soil to aqueous are predominance function. This study provides comprehensive scenes in PAEs degradation with persulfate oxidation activated by thermal in soil, reveal the difference of degradation between DBP and DEHP is structure-dependent. So that we provide fundamental understanding and theoretical operation for subsequent filed treatment of various structural emerging pollutants PAEs contaminated soil with thermal activated persulfate.

Biodegradation of phthalic acid and terephthalic acid by Comamonas testosteroni strains

Phthalic acid isomers are the monomers of phthalate molecules, also known as phthalic acid esters, widely employed in the plastics industry. This study aims to investigate the biodegradation of phthalic acid (PA) and terephthalic acid (TPA) by five industry-borne Comamonas testosteroni strains: 3APTOL, 3ABBK, 2B, 3A1, and C8. To assess the ability of C. testosteroni strains to biodegrade phthalic acid isomers in fermentation media, an analytical method was employed, consisting of high-performance liquid chromatography (HPLC) analyses. Subsequently, molecular screening of the genomic and plasmid DNA was conducted to identify the degradative genes responsible for the breakdown of these chemicals. The genes of interest, including ophA2, tphA2, tphA3, pmdA, and pmdB, were screened by real-time PCR. The five C. testosteroni strains effectively degraded 100% of 100 mg/L PA (p = 0.033) and TPA (p = 0.0114). Molecular analyses indicated that all C. testosteroni strains contained the pertinent genes at different levels within their genomes and plasmids, as reflected in the threshold cycle (Ct) values. Additionally, DNA temperature of melting (Tm) analyses uncovered minor differences between groups of genes in genomic and plasmid DNA. C. testosteroni strains could be excellent candidates for the removal of phthalic acid isomers from environmental systems.

Pollution characteristics, sources, and health risks of phthalate esters in ambient air: A daily continuous monitoring study in the central Chinese city of Nanchang

In recent years, the atmospheric pollution caused by phthalate esters (PAEs) has been increasing due to the widespread use of PAE-containing materials. Existing research on atmospheric PAEs lacks long-term continuous observation and samples from cities in central China. To investigate the pollution characteristics, sources, and health risks of PAEs in the ambient air of a typical city in central China, daily PM2.5 samples were collected in Nanchang from November 2020 to October 2021. In this study, the detection and quantification of six significant PAE contaminants, namely diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), diisobutyl phthalate (DIBP), Di-2-ethylhexyl phthalate (DEHP), di-n-octyl phthalate (DnOP), and diisodecyl phthalate (DIDP), were accomplished using gas chromatography and mass spectrometry. The results revealed that the concentrations of DEP, DnBP, DEHP, and DnOP were relatively high. Higher temperatures promote the volatilization of PAEs, leading to an increase in the gaseous and particulate PAE concentrations in warm seasons and winter pollution scenarios. The results of principal component analysis show that PAEs mainly come from volatile products and polyvinylchloride plastics. Using positive matrix factorization analysis, it is shown that these two sources contribute 67.0% and 33.0% in atmosphere PAEs, respectively. Seasonally, the contribution of volatile products to both gaseous and particulate PAEs substantially increases during warm seasons. The residents in Nanchang exposed to PAEs have a negligible non-cancer risk and a potential low cancer risk. During the warm seasons, more PAEs are emitted into the air, which will increase the toxicity of PAEs and their impact on human health.

Analysis and remediation of phthalates in aquatic matrices: current perspectives

Phthalic acid esters (PAEs) are high production volume chemicals used extensively as plasticizers, to increase the flexibility of the main polymer. They are reported to leach into their surroundings from plastic products and are now a ubiquitous environmental contaminant. Phthalate levels have been determined in several environmental matrices, especially in water. These levels serve as an indicator of plasticizer abuse and plastic pollution, and also serve as a route of exposure to different species including humans. Reports published on effects of different PAEs on experimental models demonstrate their carcinogenic, teratogenic, reproductive, and endocrine disruptive effects. Therefore, regular monitoring and remediation of environmental water samples is essential to ascertain their hazard quotient and daily exposure levels. This review summarises the extraction and detection techniques available for phthalate analysis in water samples such as chromatography, biosensors, immunoassays, and spectroscopy. Current remediation strategies for phthalate removal such as adsorption, advanced oxidation, and microbial degradation have also been highlighted.

Occurrence and Health Risk Assessment of Phthalates in Municipal Drinking Water Supply of a Central Indian City

In this study, the occurrence of phthalates in the municipal water supply of Nagpur City, India, was studied for the first time. The study aimed to provide insights into the extent of phthalate contamination and identify potential sources of contamination in the city's tap water. We analyzed fifteen phthalates and the total concentration (∑15phthalates) ranged from 0.27 to 76.36 µg L-1. Prominent phthalates identified were di-n-butyl phthalate (DBP), di-isobutyl phthalate (DIBP), benzyl butyl phthalate (BBP), di (2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DNOP), and di-nonyl phthalate (DNP). Out of the fifteen phthalates analyzed, DEHP showed the highest concentration in all the samples with the median concentration of 2.27 µg L-1, 1.39 µg L-1, 1.83 µg L-1, 2.02 µg L-1, respectively in Butibori, Gandhibaag, Civil Lines, and Kalmeshwar areas of the city. In 30% of the tap water samples, DEHP was found higher than the EPA maximum contaminant level of 6 µg L-1. The average daily intake (ADI) of phthalates via consumption of tap water was higher for adults (median: 0.25 µg kg-1 day-1) compared to children (median: 0.07 µg kg-1 day-1). The hazard index (HI) calculated for both adults and children was below the threshold level, indicating no significant health risks from chronic toxic risk. However, the maximum carcinogenic risk (CR) for adults (8.44 × 10-3) and children (7.73 × 10-3) was higher than the threshold level. Knowledge of the sources and distribution of phthalate contamination in municipal drinking water is crucial for effective contamination control and management strategies.

Point-of-Use SERS Approach for Efficient Determination and Removal of Phthalic Acid Esters Based on a Metal-Organic Framework-Coated Melamine Sponge

Phthalic acid esters (PAEs) are ubiquitous environmental contaminants, and their real-time monitoring and removal remain challenging. Herein, a point-of-use (POU) device integrating adsorption, surface-enhanced Raman spectroscopy (SERS), and removal strategy was developed and realized ultrafast on-site determination of PAEs and cleanup of them from water. A piece of flexible melamine sponge (MS) was coated with gold nanostars (AuNSs) and metal-organic frameworks (MOFs), thus obtaining SERS activity and adsorption capacity. Based on this multifunctional AuNSs@MOFs/MS composite, clear trends were observed between SERS signal intensity and concentration of di(2-ethylhexyl)phthalate (DEHP) and dibutyl phthalate (DBP). The method detection limits of DEHP and DBP were calculated to be 0.75 × 10-7 and 0.67 × 10-7 M in water, respectively, proving good sensitivity. Furthermore, this POU device exhibited satisfactory adsorption capacity (∼82.3 g/g for DBP and ∼90.0 g/g for DEHP), high adsorption efficiency (equilibrium in 100 s), and good regeneration capability (removal efficiency >70% after 5 cycles). The applicability of this device was verified by its good determination and removal performance in real environmental water matrices. The whole process could be completed within 5 min. This approach provides a new POU alternative for real-time monitoring and removal of PAEs in water.

Phthalates contamination in sediments: A review of sources, influencing factors, benthic toxicity, and removal strategies

Sediments provide habitat and food for benthos, and phthalates (PAEs) have been detected in numerous river and marine sediments as a widely used plastic additive. PAEs in sediments is not only toxic to benthos, but also poses a threat to pelagic fish and human health through the food chain, so it is essential to comprehensively assess the contamination of sediments with PAEs. This paper presents a critical evaluation of PAEs in sediments, which is embodied in the analysis of the sources of PAEs in sediments from multiple perspectives. Biological production is indispensable, while artificial synthesis is the most dominant, thus the focus was on analyzing the industrial and commercial sources of synthetic PAEs. In addition, since the content of PAEs in sediments varies, some factors affecting the content of PAEs in sediments are summarized, such as the properties of PAEs, the properties of plastics, and environmental factors (sediments properties and hydrodynamic conditions). As endocrine disruptors, PAEs can produce toxicity to its direct contacts. Therefore, the effects of PAEs on benthos immunity, endocrinology, reproduction, development, and metabolism were comprehensively analyzed. In addition, we found that reciprocal inhibition and activation of the systems lead to genotoxicity and apoptosis. Finally, the paper discusses the feasible measures to control PAEs in wastewater and leachate from the perspective of source control, and summarizes the in-situ treatment measures for PAEs contamination in sediments. This paper provides a comprehensive review of PAEs contamination in sediments, toxic effects and removal strategies, and provides an important reference for reducing the contamination and toxicity of PAEs to benthos.

Ultrasound for the degradation of endocrine disrupting compounds in aqueous solution: A review on mechanisms, influence of operating parameters and cost estimation

Availability of drinking water is one of the basic humanitarian goals but remains as a grand challenge that the world is facing today. Currently, water bodies are contaminated not only with conventional pollutants but also with numerous recalcitrant pollutants, such as PPCPs, endocrine disrupting compounds, etc. These emerging pollutants require special attention because of their toxicity to living organisms, bio-resistant and can sustain even after primary and secondary treatments of wastewater. Among different treatment technologies, sonolysis is found to be an innovative and promising technique for the treatment of emerging pollutants present in aqueous solution. Sonolysis is the use of ultrasound to enhance or alter chemical reactions by the formation of free radicals and shock waves which ultimately helps in degradation of pollutants. This review summarizes several studies in the sonochemical literature, including mechanisms of sonochemical process, physical and chemical effects of ultrasound, and the influence of several process variables such as ultrasound frequency, power density, temperature and pH of the medium on degradation performance for endocrine disrupting compounds. In addition, this review highlighted techno-economic perspectives focusing on the total cost required for translating the ultrasound-based processes on a large scale. Overall, the objective of this study is to exhibit a critical review of information available in the literature to encourage and promote future research on sonolysis for the degradation of Endocrine Disrupting Compounds (EDCs).

Recent advances in remediation strategies for mitigating the impacts of emerging pollutants in water and ensuring environmental sustainability

The proliferation of emerging pollutants (EPs), encompassing a range of substances such as phthalates, phenolics, pharmaceuticals, pesticides, personal care products, surfactants, and disinfection agents, has become a significant global concern due to their potential risks to the environment and human well-being. Over the past two decades, numerous research studies have investigated the presence of EPs in wastewater and aquatic ecosystems, with the United States Environmental Protection Agency (USEPA) categorizing these newly introduced chemical compounds as emerging contaminants due to their poorly understood impact. EPs have been linked to adverse health effects in humans, including genotoxic and cytotoxic effects, as well as conditions such as obesity, diabetes, cardiovascular disease, and reproductive abnormalities, often associated with their estrogenic action. Microalgae have shown promise in the detoxification of both inorganic and organic contaminants, and several large-scale microalgal systems for wastewater treatment have been developed. However, the progress of algal bioremediation can be influenced by accidental contaminations and operational challenges encountered in pilot-scale research. Microalgae employ various processes, such as bioadsorption, biouptake, and biodegradation, to effectively remediate EPs. During microalgal biodegradation, complex chemical compounds are transformed into simpler substances through catalytic metabolic degradation. Integrating algal bioremediation with existing treatment methodologies offers a viable approach for efficiently eliminating EPs from wastewater. This review focuses on the use of algal-based biological remediation processes for wastewater treatment, the environmental impacts of EPs, and the challenges associated with implementing algal bioremediation systems to effectively remove emerging pollutants.

Biodegradation of di-2-ethylhexyl phthalate by Bacillus firmus MP04 strain: parametric optimization using full factorial design

Di-2-ethylhexyl phthalate (DEHP) is used as a plasticizer in making plastics and released from landfills. This study attempted to degrade DEHP using microbial isolates. Isolates of Bacillus spp. were tested for their efficacy in degrading DEHP. Degradation was assessed using liquid chromatography-mass spectrometry (LC-MS). The most efficient DEHP degradation was achieved by Bacillus firmus MP04, which has been identified as Bacillus firmus MP04. This strain was found to use DEHP as the sole source of carbon without carbon source supplementation. Full factorial design was used to optimize the conditions for DEHP degradation which revealed the suitability of pH 7, 5% salt concentration, 20 to 37 °C temperature, and yeast extract as a nitrogen source. LC-MS elucidated the possible degradation mechanism via benzoic acid formation. However, prolonged incubation formed a typical compound denatonium benzoate due to reactions with other compounds. As maximum degradation was achieved in 4 days, prolonged incubation is not suggested. It can be concluded that new strain Bacillus firmus MP04 is the most efficient strain among all the tested strains for DEHP degradation.

Conductive Polymer-Inorganic Polythiophene/Cd0.5Zn0.5S Heterojunction with Apace Charge Separation and Strong Light Absorption for Boosting Photocatalytic Activity

In order to utilize the synergistic effect between a conductive polymer and an inorganic semiconductor to efficaciously enhance charge transfer and solve the problem of unsatisfactory performance of a single photocatalyst, thiophene (Th) was polymerized on the Cd0.5Zn0.5S nanoparticle surface to prepare a conductive polymer-inorganic polythiophene/Cd0.5Zn0.5S (PTh/CZS) heterostructrue through a simple in situ oxidation polymerization for the first time. The as-prepared PTh/CZS heterostructures significantly improved photocatalytic TCH degradation and hydrogen production activities. Especially, the 15PTh/CZS sample exhibited the optimal hydrogen production rate (18.45 mmol g-1 h-1), which was 2.51 times higher than pure Cd0.5Zn0.5S nanoparticles. In addition, 15PTh/CZS also showed very fast and efficient photodegradation ability for degrading 88% of TCH in 25 min. Moreover, the degradation rate (0.06229 min-1) was five times more than that of Cd0.5Zn0.5S. The π-π* transition characteristics, high optical absorption coefficient, wide absorption wavelength of PTh, the tight contact interface, and synergistic effect of PTh and Cd0.5Zn0.5S efficiently boosted charge transfer rate and increased the light absorption of PTh/CZS photocatalysts, which greatly enhanced the photocatalytic abilities. Besides, the mechanism of improved photocatalytic activities for TCH degradation and H2 production was also carefully proposed. Undoubtedly, this work would provide new insights into coupling conductive polymers to inorganic photocatalysts for achieving multifunctional applications in the field of photocatalysis.

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 24 h, 45% of DMP (25 mg/L) was degraded in the presence of 0.8 U/mL laccase and 0.053 mM 2, 2, 6, 6-tetramethylpiperidine-1-oxyl (TEMPO). A certain concentration (1 mM) 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.

A Review of the Analysis of Phthalates by Gas Chromatography in Aqueous and Food Matrices

As a commonly well-known industrial chemical, phthalates are produced in high volumes to be used in various consumer products (e.g., plasticizers, medical devices, construction materials, and toys) to enhance softness, durability, transparency, and flexibility. Phthalates are generally not chemically bonded to the polymer chain of the plastic in which they are mixed. Thus, they may leach, migrate, or evaporate into indoor/outdoor air, and foodstuffs. In this review, a comprehensive overview of several sample preparation methods coupled with gas chromatography for the analysis of phthalates in various kinds of complex matrices, with a focus on the last 20 years' worth of papers. The review begins by highlighting the environmental significance of phthalate pollution along with the various routes to their exposure to general population. Then, the discussion is extended to cover the pretreatment and extraction techniques for phthalates for their quantitation based on gas chromatographic approach. Finally, the present and future challenges for the detection of phthalates in aqueous and food matrices are discussed.

Adsorptive removal of dimethyl phthalate using peanut shell-derived biochar from aqueous solutions: equilibrium, kinetics, and mechanistic studies

Rise in polymer industry and extensive use of their products leads to leaching of phthalate esters and distributed into the different matrices of the environment. This chemical group has the potential to hamper the life of living organisms and ecosystem. Thus, it is essential to develop cost-effective adsorbents capable of removing these harmful compounds from the environment. In this work, peanut hull-derived biochar was taken as the adsorbent, and DMP was selected as the model pollutant or adsorbates. The biochars of different properties were produced at three pyrolysis temperatures (i.e., 450, 550, and 650 °C) to check how temperature affected the adsorbent properties and adsorption performance. Consequently, the performance of biochars for DMP adsorption was thoroughly studied by the combination of experiments and compared with commercial activated carbon (CAC). All the adsorbents are meticulously characterized using various analytical techniques and used for adsorption DMP from aqueous solutions. The results suggested that adsorption was favoring chemisorption with multi-layered adsorption as adsorption kinetics and isotherm are in good alignment with pseudo-second-order kinetics and Freundlich isotherm, respectively. Further, thermodynamic study revealed DMP adsorption on adsorbent is physically spontaneous and endothermic. The removal efficiency order of four adsorbent was as follows: BC650 > CAC > BC550 > BC450 with maximum efficiency of 98.8% for BC650 followed by 98.6% for CAC at optimum conditions. And as it is a short carbon chain PAE, dominant mechanisms of adsorption for DMP onto porous biochar were H-bonding, π-π EDA interactions, and diffusion within the pore spaces. Therefore, this study can provide strategies for the synthesis of biochar for effectively removing DMP from aqueous solution.

Advanced oxidation processes for phthalate esters removal in aqueous solution: a systematic review

This study addresses a systematic review of the scientific literature to evaluate the most common advanced oxidation processes (AOP) for the removal of phthalate esters (PE) in aqueous matrices. Six AOP were reviewed for PE degradation such as processes based on photolysis, Fenton, ozonation and sulfate radicals ( SO 4 • - ), combined AOP and other processes. The PE degradation efficiencies by AOP processes ranged from 40.3 to 100%. In the reviewed literature, an initial PE concentration within 0.04-250 mg/L was applied. The H₂O₂ concentrations used in the UV/H₂O₂ process and O₃ concentrations in ozonation-based processes ranged between 0.85-1,360.6 mg/L and 2-4,971 mg/L, respectively. Based on the reported results, the PE oxidation data fit well to the pseudo-first order kinetic model. A review of the studies revealed that many oxidant species are produced in the AOP, including hydroxyl radicals (^•OH), SO 4 • - , superoxide radical anions ( O 2 - • ), hydroperoxyl radicals (HO₂ ^•), hydrogen peroxide (H₂O₂), and singlet oxygen (O₂). Among these oxidants, ^•OH play a key role in the degradation of PE. However, SO 4 • - are more effective and efficient than ^•OH since SO 4 • - has a higher oxidation power (E = 2.5-3.1 V) compared to ^•OH radicals (E = 1.8-2.7 V). In different AOP processes, the aromatic rings of PE are destroyed by ^•OH and produce intermediates such as phthalic acid (C₆H₄(CO₂H)₂), benzoic acid ethyl ester (C₉H₁₀O₂), 2, 5-dihydroxybenzoic acid (C₇H₆O₄), formic acid (CH₂O₂), acetic acid (CH₃COOH), and oxalic acid (C₂H₂O₄), among some others. Until now, limited data have been reported on PE toxicity assessment. The reviewed literature has shown that AOP can be used effectively to degrade PE from aqueous matrices. However, this systematic study suggests focusing more on the evaluation of the toxicity of the effluent resulting from AOP for the decomposition of PE in future studies.

Cumulative Exposure to Phthalates and Their Alternatives and Associated Female Reproductive Health: Body Burdens, Adverse Outcomes, and Underlying Mechanisms

The global birth rate has recently shown a decreasing trend, and exposure to environmental pollutants has been identified as a potential factor affecting female reproductive health. Phthalates have been widely used as plasticizers in plastic containers, children's toys, and medical devices, and their ubiquitous presence and endocrine-disrupting potential have already raised particular concerns. Phthalate exposure has been linked to various adverse health outcomes, including reproductive diseases. Given that many phthalates are gradually being banned, a growing number of phthalate alternatives are becoming popular, such as di(isononyl) cyclohexane-1,2-dicarboxylate (DINCH), di(2-ethylhexyl) adipate (DEHA), and di(2-ethylhexyl) terephthalate (DEHTP), and they are beginning to have a wide range of environmental effects. Studies have shown that many phthalate alternatives may disrupt female reproductive function by altering the estrous cycle, causing ovarian follicular atresia, and prolonging the gestational cycle, which raises growing concerns about their potential health risks. Herein, we summarize the effects of phthalates and their common alternatives in different female models, the exposure levels that influence the reproductive system, and the effects on female reproductive impairment, adverse pregnancy outcomes, and offspring development. Additionally, we scrutinize the effects of phthalates and their alternatives on hormone signaling, oxidative stress, and intracellular signaling to explore the underlying mechanisms of action on female reproductive health, because these chemicals may affect reproductive tissues directly or indirectly through endocrine disruption. Given the declining global trends of female reproductive capacity and the potential ability of phthalates and their alternatives to negatively impact female reproductive health, a more comprehensive study is needed to understand their effects on the human body and their underlying mechanisms. These findings may have an important role in improving female reproductive health and in turn decreasing the number of complications during pregnancy.

Insights into the Photoelectrocatalytic Behavior of gCN-Based Anode Materials Supported on Ni Foams

Graphitic carbon nitride (gCN) is a promising n-type semiconductor widely investigated for photo-assisted water splitting, but less studied for the (photo)electrochemical degradation of aqueous organic pollutants. In these fields, attractive perspectives for advancements are offered by a proper engineering of the material properties, e.g., by depositing gCN onto conductive and porous scaffolds, tailoring its nanoscale morphology, and functionalizing it with suitable cocatalysts. The present study reports on a simple and easily controllable synthesis of gCN flakes on Ni foam substrates by electrophoretic deposition (EPD), and on their eventual decoration with Co-based cocatalysts [CoO, CoFe₂O₄, cobalt phosphate (CoPi)] via radio frequency (RF)-sputtering or electrodeposition. After examining the influence of processing conditions on the material characteristics, the developed systems are comparatively investigated as (photo)anodes for water splitting and photoelectrocatalysts for the degradation of a recalcitrant water pollutant [potassium hydrogen phthalate (KHP)]. The obtained results highlight that while gCN decoration with Co-based cocatalysts boosts water splitting performances, bare gCN as such is more efficient in KHP abatement, due to the occurrence of a different reaction mechanism. The related insights, provided by a multi-technique characterization, may provide valuable guidelines for the implementation of active nanomaterials in environmental remediation and sustainable solar-to-chemical energy conversion.

Remediation of phthalate acid esters from contaminated environment—Insights on the bioremedial approaches and future perspectives

Phthalates are well-known emerging pollutants that are toxic to the environment and human health. Phthalates are lipophilic chemicals used as plasticizers in many of the items for improving their material properties. These compounds are not chemically bound and are released to the surroundings directly. Phthalate acid esters (PAEs) are endocrine disruptors and can interfere with hormones, which can cause issues with development and reproduction, thus there is a huge concern over their existence in various ecological surroundings. The purpose of this review is to explore the occurrence, fate, and concentration of phthalates in various environmental matrices. This article also covers the phthalate degradation process, mechanism, and outcomes. Besides the conventional treatment technology, the paper also aims at the recent advancements in various physical, chemical, and biological approaches developed for phthalate degradation. In this paper, a special focus has been given on the diverse microbial entities and their bioremedial mechanisms executes the PAEs removal. Critically, the analyses method for determining intermediate products generated during phthalate biotransformation have been discussed. Concluisvely, the challenges, limitations, knowledge gaps and future opportunities of bioremediation and their significant role in ecology have also been highlighted.

Heterogeneous photocatalytic oxidation for the removal of organophosphorus pollutants from aqueous solutions: A review

Organophosphorus pollutants (OPs), which are compounds containing carbon‑phosphorus bonds or phosphate derivatives containing organic groups, have received much attention from researchers because of their persistence in the aqueous environment for long periods of time and the threat they pose to human health. Heterogeneous photocatalysis has been widely applied to the removal of OPs from aqueous solutions due to its better removal effect and environmental friendliness. In this review, the removal of OPs from aqueous matrices by heterogeneous photocatalysis was presented. Herein, the application and the heterogeneous photocatalysis mechanism of OPs were described in detail, and the effects of catalyst types on degradation effect are discussed categorically. In particular, the heterojunction type photocatalyst has the most excellent effect. After that, the photocatalytic degradation pathways of several OPs were summarized, focusing on the organophosphorus pesticides and organophosphorus flame retardants, such as methyl parathion, dichlorvos, dimethoate and chlorpyrifos. The toxicity changes during degradation were evaluated, indicating that the photocatalytic process could effectively reduce the toxicity of OPs. Additionally, the effects of common water matrices on heterogeneous photocatalytic degradation of OPs were also presented. Finally, the challenges and perspectives of heterogeneous photocatalysis removal of OPs are summarized and presented.

Bacterial community shifts in a di-(2-ethylhexyl) phthalate-degrading enriched consortium and the isolation and characterization of degraders predicted through network analyses

Di-(2-ethylhexyl) phthalate (DEHP) is an extensively used and toxic phthalate plasticizer that is widely reported in marine environments. Degradation of DEHP by bacteria from several environments have been studied, but little is known about marine sediment bacteria that can degrade DEHP and other phthalate plasticizers. Therefore, in this study, we enriched a bacterial consortium C10 that can degrade four phthalate plasticizers of varying alkyl chain lengths (DEHP, dibutyl phthalate, diethyl phthalate, and dimethyl phthalate) from marine sediment. The major bacterial genera in C10 during degradation of the phthalate plasticizers were Glutamicibacter, Ochrobactrum, Pseudomonas, Bacillus, Stenotrophomonas, and Methylophaga. Growth of C10 on DEHP intermediates (mono-ethylhexyl phthalate, 2-ethylhexanol, phthalic acid, and protocatechuic acid) was studied and these intermediates enhanced the Brevibacterium, Ochrobactrum, Achromobacter, Bacillus, Sporosarcina, and Microbacterium populations. Using a network-based approach, we predicted that Bacillus, Stenotrophomonas, and Microbacterium interacted cooperatively and were the main degraders of phthalate plasticizers. Through selective isolation techniques, we obtained twenty isolates belonging to Bacillus, Microbacterium, Sporosarcina, Micrococcus, Ochrobactrum, Stenotrophomonas, Alcaligenes, and Cytobacillus. The best DEHP-degraders were Stenotrophomonas acidaminiphila OR13, Microbacterium esteraromaticum OR16, Sporosarcina sp. OR19, and Cytobacillus firmus OR20 (83.68%, 59.1%, 43.4%, and 40.6% degradation of 100 mg/L DEHP in 8 d), which agrees with the prediction of key degraders. This is the first report of DEHP degradation by all four bacteria and, thus, our findings reveal as yet unknown PAE-degradation capabilities of marine sediment bacteria. This study provides insights into how bacterial communities adapt to degrade or resist the toxicities of different PAEs and demonstrates a simple approach for the prediction and isolation of potential pollutant degraders from complex and dynamic bacterial communities.

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.

Recent developments in photocatalysis of industrial effluents ։ A review and example of phenolic compounds degradation

Industrial expansion and increased water consumption have created water scarcity concerns. Meanwhile, conventional wastewater purification methods have failed to degrade recalcitrant pollutants efficiently. The present review paper discusses the recent advances and challenges in photocatalytic processes applied for industrial effluents treatment, with respect to phenolic compounds degradation. Key operational parameters including the catalyst loading, light intensity, initial pollutants concentration, pH, and type and concentrations of oxidants are evaluated and discussed. Compared to the other examined controlling parameters, pH has the highest effect on the photo-oxidation of contaminants by means of the photocatalyst ionization degree and surface charge. Furthermore, major phenolic compounds derived from industrial sources are comprehensively presented and the applicability of photocatalytic processes and the barriers in practical applications, including high energy demand, technical challenges, photocatalyst stability, and recyclability have been explored. The importance of energy consumption and operational costs for realistic large-scale processes are also discussed. Finally, research gaps in this area and the suggested direction for improving degradation efficiencies in industrial applications are presented. In the light of these premises, selective degradation processes in real water matrices such as untreated sewage are proposed.

Molecularly Imprinting Microfiltration Membranes Able to Absorb Diethyl Phthalate from Water

In this study, polypropylene porous membranes with an average pore size of 1.25 µm were modified by barrier discharge plasma. Next, molecularly imprinted layers with an imprint of diethyl phthalate (DEP) ware grafted of their surface. In order to optimize the composition of the modifying mixture various solvents, the ratios of functional monomers and the cross-linking monomer as well as various amounts of phthalate were verified. It was shown that the most effective membranes were obtained during polymerization in n-octane with the participation of functional monomers in the ratio 3:7 and the amount of phthalate 7 wt.%. The membranes were tested in the filtration process as well as static and dynamic sorption. In all of these processes, the imprinted membranes showed better properties than those without the imprint. The diethyl phthalate retention coefficient was 36.12% for membranes with a grafting yield of 1.916 mg/cm². On the other hand, DEP static sorption for the imprinted membranes was 3.87 µmol/g higher than for non-imprinted membranes. Also, in the process of dynamic sorption higher values were observed for membranes with the imprint (DS_MIM, 4.12 µmol/g; DS_NIM, 1.18 µmol/g). The membranes were also tested under real conditions. In the process of filtration of tap water contaminated with phthalate, the presence of imprints in the membrane structure resulted in more than three times higher sorption values (3.09 µmol/g) than in the case of non-imprinted membranes (1.12 µmol/g).

Phthalates removal from wastewater by different methods - a review

Phthalate esters are commonly used as plasticizers to improve the durability and workability of polymeric materials, locating and identifying them in various contexts has become a major challenge. Because of their ubiquitous use in plastic packaging and personal care items, as well as their tendency to leach out of these materials, phthalates have been detected in a variety of aquatic situations, including surface water, groundwater, drinking water, and wastewater. Phthalate esters have been shown to affect reproductive health and physical growth by disrupting the endocrine system. As a result, developing energy-efficient and effective technologies to eliminate these harmful substances from the atmosphere has become more important and urgent. This paper examines the existing techniques for treating phthalates and degradation mechanisms, as well as knowledge gaps and future research directions. These technologies include adsorption, electrochemical, photocatalysis, membrane filtration and microbial degradation. Adsorption and photo catalysis are the most widely used techniques for phthalate removal, according to the literature survey papers.

Insights into photocatalytic degradation of phthalate esters over MSnO3 perovskites (M = Mg, Ca): Experiments and density functional theory

In this study, the physicochemical and photocatalytic properties of two kinds of stannate perovskite oxides (MgSnO₃ and CaSnO₃) were investigated under simulated sunlight, where dimethyl phthalate (DMP) and diethyl phthalate (DEP) were selected as the probe pollutants. The results of photochemical characterization showed that MgSnO₃ perovskite exhibited better photocatalytic performance than CaSnO₃ perovskite. MgSnO₃ perovskite could effectively degrade 75% of DMP and 79% of DEP through pseudo-first-order reaction kinetics, which remained good in pH 3.0 to 9.0. Quenching experiments and electron paramagnetic resonance (EPR) characterization indicated that photogenerated holes (h⁺), superoxide (O₂^-), and hydroxyl radicals (OH) worked in the photo-degradation, while O₂^- played the most important role. Furthermore, intermediates identification and density functional theory (DFT) calculations were used to explore the degradation mechanism. For both DMP and DEP, the reactive oxygen species (ROS, including O₂^- and OH) were responsible for the hydroxylation of benzene ring and the breaking of the aliphatic chain, while h⁺ was prone to break the aliphatic chain. This work is expected to provide new insights on the photocatalytic mechanism of stannate perovskites for environmental remediation.

Dibutyl phthalate weakens the role of electroactive biofilm as an efficient wastewater handler and related mechanism

Plasticizer plays an imperceptible role in interfering with the structure and function of wastewater biofilms, but the inherent influence mechanism still remains unknown. Here, the responses in electrochemical, structural, microbial properties of electroactive biofilm (EAB) to plasticizer (dibutyl phthalate, DBP) were comprehensively elucidated, especially for the property variation of extracellular polymeric substances (EPS). The biofilm-0 in DBP-absent environment contributed to 22.9% and 63.9% higher current, compared to those in 1 mg/L and 10 mg/L DBP environment (biofilm-1 and biofilm-10). Chronic exposure to high-concentration DBP significantly boosted the content and distribution width of polysaccharide in EPS, but the electron exchange capacity of EPS decreased 76.6% to 0.146 μmol e^-/mg EPS for biofilm-10. The bacteria were subjected to metabolic function loss, in terms of esterase activity and membrane integrity, by using flow cytometry. The DBP exposure also imposed selective pressure on enrich EPS-secretion-related bacteria, while the Geobacter species decreased from 71.2% (biofilm-0) to 55.8% (biofilm-10). Consequently, the DBP exposure suppressed the pollutant degradation rate, which provided new insights into the EAB role as a promising core for wastewater treatment in plasticizer-existing environments.

Broccoli-liked silver phosphate nanoparticles supported on green nanofiber membrane for visible-light driven photodegradation towards water pollutants

In view of the practical application, it is imperative to develop efficient, exercisable, and visible light driven water pollution treatment materials. Herein, a high-efficiency green photocatalytic membrane for water pollution treatment is proposed and fabricated conveniently. Firstly, silver phosphate (Ag₃PO₄) nanoparticles with controlled morphology were prepared by simple liquid-phase precipitation method, and then a hierarchical structured Ag₃PO₄@polylactic acid (PLA) composite nanofiber membrane was prepared by electrospinning. Using electrospun PLA nanofiber membrane as a carrier of photocatalysts can significantly improve the dispersion of Ag₃PO₄nanoparticles, and increase the contact probability with pollutants and photocatalytic activity. The prepared PLA@Ag₃PO₄composite membrane was used to degrade methylene blue (MB) and tetracycline hydrochloride (TC) under visible light irradiation. The results showed that the removal ratio of pollutants on Ag₃PO₄@PLA composite nanofiber membrane was 94.0% for MB and 82.0% for TC, demonstrating an outstanding photocatalytic activity of composite membrane. Moreover, the PLA nanofiber membrane is a self-supported and biodegradable matrix. After five cycles, it can still achieve 88.0% of the initial photocatalytic degradation rate towards MB, showing excellent recyclability. Thus, this composite nanofiber membrane is a high-efficiency and environmental-friendly visible light driven water pollution treatment material that could be used in real applications.

Phthalates in the environment: characteristics, fate and transport, and advanced wastewater treatment technologies

Phthalates are well-known emerging contaminants that harm human health and the environment. Therefore, this review aims to discuss about the occurrence, fate, and phthalates concentration in the various environmental matrices (e.g., aquatic, sediment, soil, and sewage sludge). Hence, it is necessary to treat sources containing phthalates before discharging them to aqueous environment. Various advanced wastewater treatments including adsorption process (e.g., biochar, activated carbon), advanced oxidation processes (e.g., photo-fenton, ozonation, photocatalysis), and biological treatment (membrane bioreactor) have been successfully to address this issue with high removal efficiencies (70-95%). Also, the degradation mechanism was discussed to provide a comprehensive understanding of the phthalate removal for the reader. Additionally, key factors that influenced the phthalates removal efficiency of these technologies were identified and summarized with a view towards pilot-scale and industrial applications.

Construction of a hydrangea-like Bi2WO6/BiOCl composite as a high-performance photocatalyst

Bi2WO6 flower-like microspheres were acted as porous templates for depositing BiOCl to prepare a hydrangea-like Bi2WO6/BiOCl composite. The Bi2WO6/BiOCl heterojunction exhibits a high photocatalytic activity under visible light.

Enhanced degradation of dimethyl phthalate in wastewater via heterogeneous catalytic ozonation process: performances and mechanisms

Ozonation process is a promising yet challenging method for the removal of refractory organic matter due to the sluggish reaction for generating hydroxyl radical (˙OH) at a neutral pH condition. Herein, an efficient heterogeneous catalytic ozonation system using CeO₂/Al₂O₃ catalyst was developed to remove dimethyl phthalate (DMP) from wastewater. Under a neutral condition of pH = 6, this system achieved almost 100% DMP removal within 15 min at an optimized catalyst dosage of 30 g L⁻¹ and the ozone flow rate of 22.5 mg min⁻¹. Moreover, the catalytic ozonation system exhibited a stable degradation performance of DMP in a wider pH range (pH = 5–10). The results of electron paramagnetic resonance (EPR) and quantitative tests confirmed the ultrafast conversion of O₃ to ˙OH (0.774 μM min⁻¹) on the surface of CeO₂ based ceramic catalyst. The quenching experiments further supported the predominant role of ˙OH in the mineralization of DMP. These results highlight the potential of using the heterogeneous catalytic ozonation system for the efficient removal of refractory organic matter from wastewater.

An efficient heterogeneous catalytic ozonation system using CeO₂/Al₂O₃ catalyst was developed to remove dimethyl phthalate (DMP) from wastewater.

Atmospheric plasma-based approaches for the degradation of dimethyl phthalate (DMP) in water

Cold plasma based treatment of contaminated water is becoming a promising novel green remediation option. This study assessed the performance of two different cold plasma reactors, using, respectively, a self-pulsing discharge (SPD) and a multipin corona discharge (MCD), in the degradation of dimethyl phthalate (DMP), a persistent and ubiquitous pollutant of the aquatic environment. The process kinetics and energy efficiency, as well as the main plasma generated reactive species were determined under various operating conditions concerning the plasma feed gas and flowrate, the voltage polarity, the input power, the DMP initial concentration, the liquid conductivity, and the aqueous matrix used to prepare DMP solutions for these experiments. The MCD reactor, operated with air as plasma feed gas and negative voltage polarity, gave the best results in terms of rate and energy efficiency. Moreover, variations in plasma input power and in the liquid conductivity have limited effect on DMP degradation rate, making this reactor suitable for treating liquids with a range of initial conductivities The effects of DMP initial concentration on its rate of degradation and on the process energy efficiency were also investigated. Differences in the efficiency of production and distribution of plasma generated reactive species, notably ^•OH and H₂O₂, observed for the two tested reactors are discussed in terms of different extension of the plasma/liquid interface and diffusion into the bulk solution. It is proposed that among the reactive species, ^•OH foremost, and O₃ to a lesser extent, play a pivotal role in DMP degradation, while the contribution of H₂O₂ appears to be limited. The rate of DMP degradation was not drastically different in Milli-Q water and in tap water, a positive outcome in view of practical applications of the technology. The lower rate observed in tap than in Milli-Q water is attributed to the presence of bicarbonate and carbonate, which are known scavengers of hydroxyl radicals.

Continuous photocatalysis via photo-charging and dark-discharging for sustainable environmental remediation: Performance, mechanism, and influencing factors

Continuous photocatalysis via photo-charging and dark-discharging presents a paradigm shift in conventional photocatalysis with the requirement of continuous illumination to maintain the catalytic activity. This is expected to meet the ever-increasing demand for sustainable development of energy and environment driven by natural day-night cycles. Substantial advances in continuous photocatalysis for various environmental applications under light-dark cycles have been witnessed during the last decade. However, there lacks a systematic and critical review on basic but important information of continuous photocatalysis for environmental remediation, challenging robust scientific progress of this technology towards potential practical use. Here, the general description of continuous photocatalysis involving energy storage mechanisms (hole and electron storage) and characterizations (electron storage behaviors, release behaviors and storage capacity) has been first introduced. Importantly, the remediation performance and mechanism of continuous photocatalysis for environmental applications are qualitatively and quantitatively demonstrated, including chemical pollutant oxidation and reduction, microbial pathogen inactivation, and multifunctional treatment. In addition, key factors influencing its remediation performance are analyzed, for the first time, from both operational and environmental views. The ample opportunities in the field of continuous photocatalysis for sustainable environmental remediation are also pointed out, calling for more efforts to fill current knowledge gaps in the future.

Extending photocatalysis to the visible and NIR: the molecular strategy

Photocatalysis exploits light to perform important processes as solar fuel production by water splitting, and CO2 reduction or water and air decontamination. Therefore, photocatalysis contributes to the satisfaction of the increasing needs for clean energy, environmental remediation and, most recently, sanification. Most of the efficient semiconductor nanoparticles (NP), developed as photocatalysts, work in the ultraviolet (UV) spectral region and they are not able to exploit either visible (Vis) or near infrared (NIR) radiation. This limitation makes them unable to fully exploit the broad band solar radiaton or to be applied in indoor conditions. Recently, different approaches have been developed to extend the spectral activity of semiconductor NP, like for example band-gap engineering, integration with upconversion NP and plasmonic enhancement involving also hot-electron injection. Nevertheless, the use of organic molecules and metal complexes, for enhancing the photoactivity in the Vis and NIR, was one of the first strategies proposed for sensitization and it is still one of the most efficient. In this minireview we highlight and critically discuss the most recent and relevant achievements in the field of photocatalysis obtained by exploiting dye sensitization either via dynamic or static quenching.

Isotope Effects in Photocatalysis: An Underexplored Issue

In order to improve the performance of well-established photocatalysts and to develop new potential photocatalyst materials, an understanding of the underlying mechanisms of photocatalytic reactions is of the utmost importance. An often neglected method for studying the mechanism is the investigation of isotope effects. Although just a few studies related to isotope effects exist, it has been shown to be a powerful tool for exploring mechanisms of photocatalytic processes. Most of the reports are focused on TiO₂, which is the most studied photocatalyst, while there is a lack of data for other photocatalyst materials. This mini-review represents an overview of research utilizing isotope effects in the area of photocatalysis. The benefits and the importance of these studies will be highlighted, and the potential for these processes to be applied for the study of further photocatalytic reactions and different photocatalyst materials will be shown.

Chemico-nanotreatment methods for the removal of persistent organic pollutants and xenobiotics in water - A review

While the technologies available today can generate high-quality water from wastewater, the majority of the wastewater treatment plants are not intended to eliminate emerging xenobiotic pollutants, pharmaceutical and personal care items. Most endocrine disrupting compounds (EDCs) and personal care products (PPCPs) are more arctic than most regulated pollutants, and several of them have acid or critical functional groups. Together with the trace occurrence, EDCs and PPCPs create specific challenges for removal and subsequent improvements of wastewater treatment plants. Various technologies have been investigated extensively because they are highly persistent which leads to bioaccumulation. Researchers are increasingly addressing the human health hazards of xenobiotics and their removal. The emphasis of this review was on the promising methods available, especially nanotechnology, for the treatment of xenobiotic compounds that are accidentally released into the setting. In terms of xenobiotic elimination, nanotechnology provides better treatment than chemical treatments and their degradation mechanisms are addressed.

Advances in Homogeneous Photocatalytic Organic Synthesis with Colloidal Quantum Dots

Colloidal semiconductor quantum dots (QDs) have been proven to be excellent photocatalysts due to their high photostability, large extinction coefficients, and tunable optoelectrical properties, and have attracted extensive attention by synthetic chemists. These excellent properties demonstrate its promise in the field of photocatalysis. In this review, we summarize the recent application of QDs as homogeneous catalysts in various photocatalytic organic reactions. These meaningful works in organic transformations show the unique catalytic activity of quantum dots, which are different from other semiconductors.

Photocatalytic Inactivation as a Method of Elimination of E. coli from Drinking Water

The presence of microorganisms, specifically the Escherichia coli, in drinking water is of global concern. This is mainly due to the health implications of these pathogens. Several conventional methods have been developed for their removal; however, this pathogen is still found in most drinking water. In the continuous quest for a more effective removal approach, photocatalysis has been considered as an alternative method for the elimination of pathogens including E. coli from water. Photocatalysis has many advantages compared to the conventional methods. It offers the advantage of non-toxicity and utilizes the energy from sunlight, thereby making it a completely green route. Since most photocatalysts could only be active in the ultraviolet region of the solar spectrum, which is less than 5% of the entire spectrum, the challenge associated with photocatalysis is the design of a system for the effective harvest and complete utilization of the solar energy for the photocatalytic process. In this review, different photocatalysts for effective inactivation of E. coli and the mechanism involved in the process were reviewed. Various strategies that have been adopted in order to modulate the band gap energy of these photocatalysts have been explored. In addition, different methods of estimating and detecting E. coli in drinking water were presented. Furthermore, different photocatalytic reactor designs for photocatalytic inactivation of E. coli were examined. Finally, the kinetics of E. coli inactivation was discussed.