The environmental distribution and removal of emerging pollutants, highlighting the importance of using microbes as a potential degrader: A review

Fate of bisphenol A and nonylphenol in the lake riparian zone: Distribution, transport, and microbial response

The lake riparian zone (LRZ) is a key area of material circulation between terrestrial and aquatic ecosystems. However, the exchange of endocrine disrupting compounds (EDCs) in this area is still unknown. Thus, in this study, the distribution, convection and microbial response of two typical EDCs, bisphenol A (BPA) and nonylphenol (NP), in submerged (SS) and temporarily flooded sediment (FS) of LRZ were investigated by in-situ diffusive gradients in thin films technology. Concentrations of BPA (11.07 ± 2.49 μg/kg) and NP (20.42 ± 8.23 μg/kg) in FS significantly fluctuated with depth, conversely, their concentrations in SS increased steadily with depth (BPA: 14.01 ∼ 74.76 μg/kg; NP: 14.14 ∼ 137.01 μg/kg). BPA and NP dynamics analysis based on the DIFS (DGT-induced fluxes in sediments) model and fugacity fraction showed the water-sediment exchange capacity of BPA and NP in SS was on average 2-3 times higher than in FS. Some bacterial genera involved in nitrogen metabolism can effectively transform BPA and NP, such as Pseudomonas, Novosphingobium, and Sphingomonas, which are more active in oxygenic FS than in hypoxic SS. Considering this evidence as well as an increasing EDCs pollution, the behavior and quantification of EDCs at the water-sediment interface of the LRZ merits a further investigation.

Assessment of biodegradation and toxicity of alternative plasticizer di(2-ethylhexyl) terephthalate: Impacts on microbial biofilms, metabolism, and reactive oxygen species-mediated stress response

Although di(2-ethylhexyl) terephthalate (DOTP) is being widely adopted as a non-phthalate plasticizer, existing research primarily focuses on human and rat toxicity. This leaves a significant gap in our understanding of their impact on microbial communities. This study assessed the biodegradation and toxicity of DOTP on microbes, focusing on its impact on biofilms and microbial metabolism using Rhodococcus ruber as a representative bacterial strain. DOTP is commonly found in mass fractions between 0.6 and 20% v/v in various soft plastic products. This study used polyvinyl chloride films (PVC) with varying DOTP concentrations (range 1-10% v/v) as a surface for analysis of biofilm growth. Cell viability and bacterial stress responses were tested using LIVE/DEAD™ BacLight™ Bacterial Viability Kit and by the detection of reactive oxygen species using CellROX™ Green Reagent, respectively. An increase in the volume of dead cells (in the plastisphere biofilm) was observed with increasing DOTP concentrations in experiments using PVC films, indicating the potential negative impact of DOTP on microbial communities. Even at a relatively low concentration of DOTP (1%), signs of stress in the microbes were noticed, while concentrations above 5% compromised their ability to survive. This research provides a new understanding of the environmental impacts of alternative plasticizers, prompting the need for additional research into their wider effects on both the environment and human health.

Pesticides in the environment: Degradation routes, pesticide transformation products and ecotoxicological considerations

Among rising environmental concerns, emerging contaminants constitute a variety of different chemicals and biological agents. The composition, residence time in environmental media, chemical interactions, and toxicity of emerging contaminants are not fully known, and hence, their regulation becomes problematic. Some of the important groups of emerging contaminants are pesticides and pesticide transformation products (PTPs), which present a considerable obstacle to maintaining and preserving ecosystem health. This review article aims to thoroughly comprehend the occurrence, fate, and ecotoxicological importance of pesticide transformation products (PTPs). The paper provides an overview of pesticides and PTPs as contaminants of emerging concern and discusses the modes of degradation of pesticides, their properties and associated risks. The degradation of pesticides, however, does not lead to complete destruction but can instead lead to the generation of PTPs. The review discusses the properties and toxicity of PTPs and presents the methods available for their detection. Moreover, the present study examines the existing regulatory framework and suggests the need for the development of new technologies for easy, routine detection of PTPs to regulate them effectively in the environment.

Z-scheme Fe@Fe2O3/BiOBr heterojunction with efficient carrier separation for enhanced heterogeneous photo-Fenton activity of tetracycline degradation: Fe2+ regeneration, mechanism insight and toxicity evaluation

The recombination of photogenerated carrier leads to inefficient Fe2+ regeneration, which limits the extensive application of heterogeneous photo-Fenton. Here, a novel Fe@Fe2O3/BiOBr catalyst with Z-scheme heterojunction structure is designed, and the establishment of the Z-scheme heterojunction facilitates the separation and transfer of photogenerated carrier and maintains the superior redox capability of the system. As-prepared Fe@Fe2O3/BiOBr catalyst exhibits outstanding catalytic performance and stability, especially for the optimum composite FFB-3, its degradation efficiency of tetracycline (TC) achieves 98.22% and the mineralization degree reaches 59.48% within 90 min under natural pH. The preeminent catalytic efficiency benefited from the synergistic of heterogeneous photo-Fenton and Z-scheme carriers transfer mechanism, where Fe2+ regeneration was achieved by photogenerated electrons, and increased hydroxyl radicals were produced with the participation of H2O2 in-situ generated. The results of free-radical scavenging experiment and ESR illustrated that •OH, •O2-, 1O2 and h+ were active species participating in TC degradation. Furthermore, the TC degradation paths were proposed according to LC-MS, and the toxicity evaluation result showed that the toxicity of TC solutions was markedly decreased after degradation. This study provides an innovative strategy for heterogeneous photo-Fenton degradation of antibiotic contaminations by constructing Z-scheme heterojunctions.

Innovative remediation strategies for persistent organic pollutants in soil and water: A comprehensive review

Persistent organic pollutants (POPs) provide a serious threat to human health and the environment in soil and water ecosystems. This thorough analysis explores creative remediation techniques meant to address POP pollution. Persistent organic pollutants are harmful substances that may withstand natural degradation processes and remain in the environment for long periods of time. Examples of these pollutants include dioxins, insecticides, and polychlorinated biphenyls (PCBs). Because of their extensive existence, cutting-edge and environmentally friendly eradication strategies must be investigated. The most recent advancements in POP clean-up technology for soil and water are evaluated critically in this article. It encompasses a wide range of techniques, such as nanotechnology, phytoremediation, enhanced oxidation processes, and bioremediation. The effectiveness, cost-effectiveness, and environmental sustainability of each method are assessed. Case studies from different parts of the world show the difficulties and effective uses of these novel techniques. The study also addresses new developments in POP regulation and monitoring, highlighting the need of all-encompassing approaches that include risk assessment and management. In order to combat POP pollution, the integration of diverse remediation strategies, hybrid approaches, and the function of natural attenuation are also examined. Researchers, legislators, and environmental professionals tackling the urgent problem of persistent organic pollutants (POPs) in soil and water should benefit greatly from this study, which offers a complete overview of the many approaches available for remediating POPs in soil and water.

Occurrence, bioaccumulation, fate, and risk assessment of emerging pollutants in aquatic environments: A review

Significant concerns on a global scale have been raised in response to the potential adverse impacts of emerging pollutants (EPs) on aquatic creatures. We have carefully reviewed relevant research over the past 10 years. The study focuses on five typical EPs: pharmaceuticals and personal care products (PPCPs), per- and polyfluoroalkyl substances (PFASs), drinking water disinfection byproducts (DBPs), brominated flame retardants (BFRs), and microplastics (MPs). The presence of EPs in the global aquatic environment is source-dependent, with wastewater treatment plants being the main source of EPs. Multiple studies have consistently shown that the final destination of most EPs in the water environment is sludge and sediment. Simultaneously, a number of EPs, such as PFASs, MPs, and BFRs, have long-term environmental transport potential. Some EPs exhibit notable tendencies towards bioaccumulation and biomagnification, while others pose challenges in terms of their degradation within both biological and abiotic treatment processes. The results showed that, in most cases, the ecological risk of EPs in aquatic environments was low, possibly due to potential dilution and degradation. Future research topics should include adding EPs detection items for the aquatic environment, combining pollution, and updating prediction models.

Integrated model of ozone mass transfer and oxidation kinetic: Construction, solving and analysis

Ozone-based advanced oxidation process (O3-AOPs) is rapidly evolving, but the surge of emerging pollutants brings new challenges for ozone oxidation research. Herein, we proposed a state-of-the-art model for simultaneously analyzing both ozone mass transfer and oxidation kinetics during ozone oxidation of emerging organic contaminants. The numerical solution and graphical representations of the integrated model were utilized to analyze the dynamics of ozone and pollutant concentration. An in-depth analysis of the integrated model revealed that the reaction rate constants in this present study were higher than previously reported apparent reaction rate constants, and catalysts were not always necessary. Finally, we developed an installable mobile application (APP) that allowed the simulation of the dynamic process for ozone oxidizing organic pollutants in the laboratory, which offered theoretical support for the selection of experimental conditions. The results of model simulation not only provide scientific explanations for counter-intuitive experimental phenomena, but also optimized experimental conditions to enhance ozone utilization.

Novel insights into aerobic 17β-estradiol degradation by enriched microbial communities from mangrove sediments

Various persistent organic pollutants (POPs) including estrogens are often enriched in mangrove regions. This research investigated the estrogens pollution levels in six mangroves located in the Southern China. The estrogen levels were found to be in the range of 5.3-24.9 ng/g dry weight, suggesting that these mangroves had been seriously contaminated. The bacterial communities under estrogen stress were further enriched by supplementing 17β-estradiol (E2) as the sole carbon source. The enriched bacterial communities showed an excellent E2 degradation capacity > 95 %. These communities were able to transform E2 into estrone (E1), 4-hydroxy-estrone, and keto-estrone, etc. 16 S rDNA sequencing and metagenomics analysis revealed that bacterial taxa Oleiagrimonas, Pseudomonas, Terrimonas, and Nitratireductor etc. were the main contributors to estrogen degradation. Moreover, the genes involved in E2 degradation were enriched in the microbial communities, including the genes encoding 17β-hydroxysteroid dehydrogenase, estrone 4-hydroxylase, etc. Finally, the analyses of functional genes and binning genomes demonstrated that E2 was degraded by bacterial communities via dehydrogenation into E1 by 17β-hydroxysteroid dehydrogenase. E1 was then catabolically converted to 3aα-H-4α(3'-propanoate)- 7aβ-methylhexahydro-1,5-indanedione via 4,5-seco pathway. Alternatively, E1 could also be hydroxylated to keto-estrone, followed by B-ring cleavage. This study provides novel insights into the biodegradation of E2 by the bacterial communities in estrogen-contaminated mangroves.

Bisphenol A affects microbial interactions and metabolic responses in sludge anaerobic digestion

The widespread use of bisphenol A (BPA) has resulted in the emergence of new pollutants in various environments, particularly concentrated in sewage sludge. This study investigated the effects of BPA on sludge anaerobic digestion, focusing specifically on the interaction of microbial communities and their metabolic responses. While the influence of BPA on methane accumulation is not significant, BPA still enhanced the conversion of soluble COD, protein, and polysaccharides. BPA also positively influenced the hydrolysis-acidogenesis process, leading to 17% higher concentrations of volatile fatty acids (VFAs). Lower BPA levels (0.2-0.5 mg/kg dw) led to decreased hydrolysis and acidogenesis gene abundance, indicating metabolic inhibition; conversely, higher concentrations (1-5 mg/kg dw) increased gene abundance, signifying metabolic enhancement. Diverse methane metabolism was observed and exhibited alterations under BPA exposure. The presence of BPA impacted both the diversity and composition of microbial populations. Bacteroidetes, Proteobacteria, Firmicutes, and Chloroflexi dominated in BPA-treated groups and varied in abundance among different treatments. Changes of specific genera Sedimentibacter, Fervikobacterium, Blvii28, and Coprothermobacter in response to BPA, affecting hydrolysis and acetogenesis. Archaeal diversity declined while the hydrogenotrophic methanogen Methanospirillum thrived under BPA exposure. BPA exposure enabled microorganisms to form structured community interaction networks and boost their metabolic activities during anaerobic digestion. The study also observed the enrichment of BPA biodegradation pathways at high BPA concentrations, which could interact and overlap to ensure efficient BPA degradation. The study provides insights into the digestion performance and interactions of microbial communities to BPA stress and sheds light on the potential effect of BPA during anaerobic digestion.

A bibliometric analysis of emerging contaminants (ECs) (2001-2021): Evolution of hotspots and research trends

Emerging contaminants (ECs) have attracted increasing attention in the past two decades because of their ubiquitous existence and high environmental risk. Understanding the progress of research and the evolution of hot topics is critical. This study provides a bibliometric review, along with a quantitative trend analysis of approximately 8000 publication records dated from 2001 to 2021. Wider distribution in various subjects was discovered in terms of publication numbers, indicating a strong tendency for EC research to become an interdisciplinary topic. Visualization of term co-occurrence analysis revealed that the ECs study went through three stages over time: identification and detection, traceability and risk, and process and control. Quantitative trend analysis revealed that antibiotics, microplastics, endocrine disrupting chemicals (EDCs), per/poly-fluoroalkyl substances (PFAS), pesticides, heavy metals, and nanoparticles are attracting increasing attention, whereas conventional pharmaceuticals, persistent organic pollutants, and materials such as benzotriazole, diclofenac, bisphenol A, carbamazepine, triclosan, and titanium dioxide exhibit a downward trend. PFAS and EDCs are considered potential future core hotspots for the hysteretic rise in research attention compared with conventional ECs. Furthermore, analysis of research linkage and the developing stages of ECs could be possible approach to determine the evolution of hotspots in ECs study. This study provides objective and comprehensive insights into the research landscape of ECs, which may shed light on future developmental directions for researchers interested in this field.

A Co-based nitrogen-doped lignin carbon catalyst with high stability and wide operating window for rapid degradation of antibiotics

Co-based catalysts play a crucial role in the activation of peroxymonosulfate (PMS) for degradation contaminants. However, the practical application of such catalysts is hindered by challenges like the self-aggregation of Co nanoparticles and leaching of Co2+. In this study, the Co-based catalyst Co-N/C@CL was synthesized from carboxymethylated lignin obtained by grafting abundant carboxymethyl groups into alkali lignin, in which the presence of these carboxymethyl groups enhanced its water solubility and allowed the formation of stable macromolecular complexes with Co2+. This catalyst exhibited a high specific surface area (521.8 m2·g-1) and a uniform distribution of Co nanoparticles. Consequently, the Co-N/C@CL/PMS system could completely remove 20 ppm tetracycline (TC) in 2 min at a rate of 2.404 min-1. Experimental results and DFT calculations revealed that the synergistic effect of lignin carbon and Co NPs accelerated the cleavage and electron transfer of OO bonds, thus promoting the formation of 1O2, OH and SO4-, with 1O2 emerging as the predominant contributor. Moreover, Co-N/C@CL displayed excellent cycling stability and low Co2+ leaching. This work not only provides a feasible strategy for the preparation of highly active and stable Co-based carbon materials but also offers a promising catalyst for the efficient degradation of TC.

Nuclear receptor superfamily structural diversity in pacific oyster: In silico identification of estradiol binding candidates

The increasing presence of anthropogenic contaminants in aquatic environments poses challenges for species inhabiting contaminated sites. Due to their structural binding characteristics to ligands that inhibit or activate gene transcription, these xenobiotic compounds frequently target the nuclear receptor superfamily. The present work aims to understand the potential interaction between the hormone 17-β-estradiol, an environmental contaminant, and the nuclear receptors of Crassostrea gigas, the Pacific oyster. This filter-feeding, sessile oyster species is subject to environmental changes and exposure to contaminants. In the Pacific oyster, the estrogen-binding nuclear receptor is not able to bind this hormone as it does in vertebrates. However, another receptor may exhibit responsiveness to estrogen-like molecules and derivatives. We employed high-performance in silico methodologies, including three-dimensional modeling, molecular docking and atomistic molecular dynamics to identify likely binding candidates with the target moecule. Our approach revealed that among the C. gigas nuclear receptor superfamily, candidates with the most favorable interaction with the molecule of interest belonged to the NR1D, NR1H, NR1P, NR2E, NHR42, and NR0B groups. Interestingly, NR1H and NR0B were associated with planktonic/larval life cycle stages, while NR1P, NR2E, and NR0B were associated with sessile/adult life stages. The application of this computational methodological strategy demonstrated high performance in the virtual screening of candidates for binding with the target xenobiotic molecule and can be employed in other studies in the field of ecotoxicology in non-model organisms.

High biosorption of cationic dye onto a novel material based on paper mill sludge

The valorization of paper mill sludge (PMS) is the main goal of this study. The emissions of PMS continue to increase at global scale, especially from packaging paper and board sectors. The raw sludge was used to prepare an adsorbent to remove toxic pollutants from wastewater, the methylene blue (MB), an organic dye. Firstly, the physico-chemical characterization of PMS was done determining the crystalline phases of PMS fibers, the content of main elements, and the pH zero point charge, which was determined at around pH 7. The adsorption of MB on PMS powder was studied at 18 °C with an agitation of 200 rpm, being the best operating conditions 30 min of contact time, 250 mg L-1 of initial MB concentration and 0.05 g in 25 mL of adsorbent dose. Experimental data of MB adsorption was fitted to Langmuir and Freundlich isotherm equations. The Langmuir model was more accurate for the equilibrium data of MB adsorption at pH 5.1. The PFOM and PSOM were adjusted to experimental adsorption kinetics data, being PSOM, which describes better the MB adsorption by PMS powder. This was confirmed by calculating the maximum adsorption capacity with PSOM, which was 42.7 mg g-1, being nearly similar of the experimental value of 43.5 mg g-1. The analysis of adsorption thermodynamics showed that the MB was adsorbed exothermically with a ΔH0 = - 20.78 kJ mol-1, and spontaneously with ΔG0 from - 0.99 to - 6.38 kJ mol-1 in the range of temperature from 291 to 363 K, respectively. These results confirm that the sludge from paper industry can be used as biosorbent with remarkable adsorption capacity and low cost for the treatment of wastewater. PMS can be applied in the future for the depollution of the effluents from the textile industry, which are highly charged with dyes.

Iron-loaded carbon black prepared via chemical vapor deposition as an efficient peroxydisulfate activator for the removal of rhodamine B from water

The excessive use of organic pollutants like organic dyes, which enter the water environment, has led to a significant environmental problem. Finding an efficient method to degrade these pollutants is urgent due to their detrimental effects on aquatic organisms and human health. Carbon-based catalysts are emerging as highly promising and efficient alternatives to metal catalysts in Fenton-like systems. They serve as persulfate activators, effectively eliminating recalcitrant organic pollutants from wastewater. In this study, iron-loaded carbon black (Fe-CB) was synthesized from tire waste using chemical vapor deposition (CVD). Fe-CB exhibited high efficiency as an activator of peroxydisulfate (PDS), facilitating the effective degradation and mineralization of rhodamine B (RhB) in water. A batch experiment and series characterization were conducted to study the morphology, composition, stability, and catalytic activity of Fe-CB in a Fenton-like system. The results showed that, at circumneutral pH, the degradation and mineralization efficiency of 20 mg L-1 RhB reached 92% and 48% respectively within 60 minutes. Fe-CB exhibited excellent reusability and low metal leaching over five cycles while maintaining almost the same efficiency. The degradation kinetics of RhB was found to follow a pseudo-first-order model. Scavenging tests revealed that the dominant role was played by sulfate (SO4-˙) and superoxide (O2-˙) radicals, whereas hydroxyl radicals (OH˙) and singlet oxygen (1O2) played a minor role in the degradation process. This study elucidates the detailed mechanism of PDS activation by Fe-CB, resulting in the generation of reactive oxygen species. It highlights the effectiveness of Fe-CB/PDS in a Fenton-like system for the treatment of water polluted with organic dye contaminants. The research provides valuable insights into the potential application of carbon black derived from tire waste for environmental remediation.

Cost estimation of synthesis and utilization of nano-adsorbents on the laboratory and industrial scales: A detailed review

The recent regulations pertaining to the circular economy have unlocked new prospects for researchers. In contrast to the unsustainable models associated with the linear economy, integration of concepts of circular economy braces reducing, reusing, and recycling of waste materials into high-end products. In this regard, adsorption is a promising and cost-effective water treatment technology for handling conventional and emerging pollutants. Numerous studies are published annually to investigate the technical performance of nano-adsorbents and nanocomposites in terms of adsorption capacity and kinetics. Yet, economic performance evaluation is rarely discussed in the literature. Even if an adsorbent shows high removal efficiency towards a specific pollutant, its high preparation and/or utilization costs might hinder its real-life use. This tutorial review aims at illustrating cost estimation methods for the synthesis and utilization of conventional and nano-adsorbents. The current treatise discusses the synthesis of adsorbents on a laboratory scale where the raw material, transportation, chemical, energy, and any other costs are discussed. Moreover, equations for estimating the costs at the large-scale adsorption units for wastewater treatment are illustrated. This review focuses on introducing these topics to non-specialized readers in a detailed but simplified manner.

Advancements in nanomaterial-based aptasensors for the detection of emerging organic pollutants in environmental and biological samples

The combination of nanomaterials (NMs) and aptamers into aptasensors enables highly specific and sensitive detection of diverse pollutants. The great potential of aptasensors is recognized for the detection of diverse emerging organic pollutants (EOPs) in different environmental and biological matrices. In addition to high sensitivity and selectivity, NM-based aptasensors have many other advantages such as portability, miniaturization, facile use, and affordability. This work showcases the recent advances achieved in the design and fabrication of NM-based aptasensors for monitoring EOPs (e.g., hormones, phenolic contaminants, pesticides, and pharmaceuticals). On the basis of their sensing mechanisms, the covered aptasensing systems are classified as electrochemical, colorimetric, PEC, fluorescence, SERS, and ECL. Special attention has been paid to the fabrication processes, analytical achievements, and sensing mechanisms of NM-based aptasensors. Further, the practical utility of aptasensing approaches has also been assessed based on their basic performance metrics (e.g., detection limits, sensing ranges, and response times).

Pollutant impacts on bacteria in surface water and sediment: Conventional versus emerging pollutants in Taihu Lake, China

Bacteria play a critical role in biogeochemical cycling, self-purification, and food web fueling in surface freshwater ecosystems. However, the comparison between the impacts of conventional and emerging pollutants on the bacteria in surface water and sediment remains unclear and requires for an in-depth understanding to assess ecological risk and select associated bioindicators. Taihu Lake, a typical shallow lake in China, was divided into pollutant impacted and less-impacted zones for sampling. Spatial distributions of conventional pollutants, emerging pharmaceuticals, and bacterial communities were investigated in surface water and sediment. The correlations of pollutants with bacterial communities and the variations in bacterial functions were analyzed to help assess the pollutant influences on bacteria. The results showed that the water quality index and trophic level index across the whole lake were at medium to good, and mesotropher to light eutropher grades, respectively, indicating a relatively good control on conventional pollutants in water. Target pharmaceuticals were at much higher concentrations in water of the impacted zone compared to the less-impacted zone, exhibiting close positive relationships with the bacterial phyla in the impacted water. The ratio of Firmicutes to Proteobacteria in surface water is suggested as a plausible bioindicator to evaluate the level of inflow pharmaceutical contamination and the risk of relevant bacterial resistance in the outflow. In sediment, no significant difference was observed for pharmaceuticals between the two zones, whereas total phosphorus and orthophosphate were substantially higher in the impacted zone. Phosphorus pollutants were tightly associated with the bacterial genera in the impacted sediment, likely relating to the increase in iron- or sulfate-reducing bacteria which implies the potential risk of phosphorus releasing from sediment to water.

Two QSAR models for predicting the toxicity of chemicals towards Tetrahymena pyriformis based on topological-norm descriptors and spatial-norm descriptors

Quantitative structure-activity relationship (QSAR) is important for safe, rapid and effective risk assessment of chemicals. In this study, two QSAR models were established with 1230 chemicals to predict toxicity towards Tetrahymena pyriformis using multiple linear regression (MLR) method. The topological(T)-QSAR model was developed by using topological-norm descriptors generated from the topological structure, and the spatial(S)-QSAR model were built with spatial-norm descriptors obtained from the three-dimensional structure of molecules and topological-norm descriptors. The r²_training and r²_test are 0.8304 and 0.8338 for the T-QSAR model, and 0.8485 and 0.8585 for the S-QSAR model, which means that T-QSAR model and S-QSAR model can be used to predict toxicity quickly and accurately. In addition, we also conducted validation on the developed models. Satisfying validation results and statistical parameters demonstrated that QSAR models based on the topological-norm descriptors and spatial-norm descriptors proposed in this paper could be further utilized to estimate the toxicity of chemicals towards Tetrahymena pyriformis.

Simultaneous Cr (VI) reduction and diazinon oxidation with organometallic sludge formation under photolysis: kinetics, degradation pathways, and mechanism

In this study, simultaneous removal of an organic matter (diazinon, DIZ) and an inorganic substance (chromium, Cr) was used. Breaking down of organic matter by UV irradiation produces various radicals, including sulfides, carboxyl, hydroxyl, hydrated electrons, and various organic radicals that are highly reactive and help us to precipitation inorganic substance (Cr). The optimal condition was 30:1 DIZ:Cr molar ratio, pH 9, and about 100% and 82.3% of DIZ and Cr were obtained in 30 min. Cr deposition was very slow at first. After the destruction of the DIZ structure, Cr deposition began, and various types of sludge with disturbed properties were formed. These sledges were analyzed by FTIR analysis and showed that green sludge could be chromium (III) hydroxide; brown sludge due to chromium (III) hydroxide, tiny green crystals from chromium (III) oxide, red brick from chromium (II) acetate chromium trioxide, as well as black sludge caused by chromium oxide were identified. In UV/DIZ/Cr process, kobs and robs range obtained 0.33-0.15 and 16.8-23.4 $ with both Cr and DIZ concentration increased from 50 to 150 mg L-1. Also, EEO for Cr precipitation was 24.65 to 5.74 and for DIZ 12.54 to 4.73 (kwh m-3). Depending on the amount of energy consumption, TCS was 37.19 to 10.47 for Cr precipitation and 4.46 to 1.25 $. It is important to note that when both pollutants are exposed to ultraviolet light, more energy and cost are generally required from UV/DIZ process and less than of UV/Cr process. But it should be noted that in fact 50 mg L-1 of chromium and 50 mg L-1 of DIZ are being removed at the same time. In UV/DIZ and UV/Cr processes that are exposed to ultraviolet radiation alone, only one of them is removed. Also, when these two pollutants are being removed at the same time, the total amount of energy is much less than the total energy consumption of the pollutants one by one.

Biochar for the Removal of Emerging Pollutants from Aquatic Systems: A Review

Water contaminated with emerging pollutants has become a serious environmental issue globally. Biochar is a porous and carbon-rich material produced from biomass pyrolysis and has the potential to be used as an integrated adsorptive material. Many studies have shown that biochar is capable to adsorb emerging pollutants from aquatic systems and could be used to solve the water pollution problem. Here, we provided a dual perspective on removing emerging pollutants from aquatic systems using biochar and analyzed the emerging pollutant removal efficiency from the aspects of biochar types, pollutant types and coexistence with heavy metals, as well as the associated mechanisms. The potential risks and future research directions of biochar utilization are also presented. This review aims to assist researchers interested in using biochar for emerging pollutants remediation in aquatic systems and facilitate research on emerging pollutants removal, thereby reducing their environmental risk.

Chemicals/materials of emerging concern in farmlands: sources, crop uptake and potential human health risks

Certain chemicals/materials that are contaminants of emerging concern (CECs) have been widely detected in water bodies and terrestrial systems worldwide while other CECs occur at undetectable concentrations. The primary sources of CECs in farmlands are agricultural inputs, such as wastewater, biosolids, sewage sludge, and agricultural mulching films. The percent increase in cropland area during 1950-2016 was 30 and the rise in land use for food crops during 1960-2018 was 100-500%, implying that there could be a significant CEC burden in farmlands in the future. In fact, the alarming concentrations (μg kg^-1) of certain CECs such as PBDEs, PAEs, and PFOS that occur in farmlands are 383, 35 400 and 483, respectively. Also, metal nanoparticles are reported even at the mg kg^-1 level. Chronic root accumulation followed by translocation of CECs into plants results in their detectable concentrations in the final plant produce. Thus, there is a continuous flow of CECs from farmlands to agricultural produce, causing a serious threat to the terrestrial food chain. Consequently, CECs find their way to the human body directly through CEC-laden plant produce or indirectly via the meat of grazing animals. Thus, human health could be at the most critical risk since several CECs have been shown to cause cancers, disruption of endocrine and cognitive systems, maternal-foetal transfer, neurotoxicity, and genotoxicity. Overall, this comprehensive review provides updated information on contamination of chemicals/materials of concern in farmlands globally, sources for their entry, uptake by crop plants, and their likely impact on the terrestrial food chain and human health.

Polystyrene microplastics and nanoplastics distinctively affect anaerobic sludge treatment for hydrogen and methane production

Microplastics and nanoplastics generally accumulated in waste activated sludge (WAS) after biological wastewater treatment. Currently, researches mainly focused on how plastics affected a particular sludge treatment method, without the comparison of different sludge systems. Herein, distinct responses of hydrogen-producing and methane-producing sludge systems were comprehensively evaluated with polystyrene microplastics (PS-MPs) and nanoplastics (PS-NPs) existence. Experimental results showed that PS particles would stimulate inhibition on anaerobic gas production except that PS-MPs were conducive to hydrogen accumulation, which was caused by the enhanced solubilization. Mechanistic investigation demonstrated that severe inhibition of PS-NPs to hydrogen production was derived from the excessively inhibitory hydrolysis despite of improving solubilization. Varying degrees of inhibition to acidification and methanation collectively contributed to reduced methane accumulation with exposure to PS-MPs and PS-NPs. Excessive oxidative stress would be generated in the presence of PS-MPs or PS-NPs, deteriorating microbial activities and richness of species responsible for hydrogen or methane production.

Integrating Reactive Chlorine Species Generation with H2 Evolution in a Multifunctional Photoelectrochemical System for Low Operational Carbon Emissions Saline Sewage Treatment

Conventional wastewater treatment plants (WWTPs) suffer from high carbon emissions and are inefficient in removing emerging organic pollutants (EOPs). Consequently, we have developed a low operational carbon emissions multifunctional photoelectrochemical (PEC) system for saline sewage treatment to simultaneously remove organic pollutants, ammonia, and bacteria, coupled with H₂ evolution. A reduced BiVO₄ (r-BiVO₄) photoanode with enhanced PEC properties, ascribed to constructing sufficient oxygen vacancies and V⁴⁺ species, was synthesized for the aforementioned technique. The PEC/r-BiVO₄ process could treat saline sewage to meet local WWTPs' discharge standard in 40 min at 2.0 V vs Ag/AgCl and completely degrade carbamazepine (one of EOPs), coupled with 633 μmol of H₂ production; 93.29% reduction in operational carbon emissions and 77.82% decrease in direct emissions were achieved by the PEC/r-BiVO₄ process compared with large-scale WWTPs, attributed to the restrained generation of CH₄ and N₂O. The PEC system activated chloride ions in sewage to generate numerous reactive chlorine species and facilitate ^•OH production, promoting contaminants removal. The PEC system exhibited operational feasibility at varying pH and total suspended solids concentrations and has outstanding reusability and stability, confirming its promising practical potential. This study proposed a novel PEC reaction for reducing operational carbon emissions from saline sewage treatment.

Engineering microbes for enhancing the degradation of environmental pollutants: A detailed review on synthetic biology

Anthropogenic activities resulted in the deposition of huge quantities of contaminants such as heavy metals, dyes, hydrocarbons, etc into an ecosystem. The serious ill effects caused by these pollutants to all living organisms forced in advancement of technology for degrading or removing these pollutants. This degrading activity is mostly depending on microorganisms owing to their ability to survive in harsh adverse conditions. Though native strains possess the capability to degrade these pollutants the development of genetic engineering and molecular biology resulted in engineering approaches that enhanced the efficiency of microbes in degrading pollutants at faster rate. Many bioinformatics tools have been developed for altering/modifying genetic content in microbes to increase their degrading potency. This review provides a detailed note on engineered microbes - their significant importance in degrading environmental contaminants and the approaches utilized for modifying microbes. The genes responsible for degrading the pollutants have been identified and modified fir increasing the potential for quick degradation. The methods for increasing the tolerance in engineered microbes have also been discussed. Thus engineered microbes prove to be effective alternate compared to native strains for degrading pollutants.

Bio-removal of emerging pollutants by advanced bioremediation techniques

This review highlights the relevance of bioremediation techniques for the removal of emerging pollutants (EPs). The EPs are chemical or biological pollutants that are not currently monitored or regulated by environmental authorities, but which can enter the environment and cause harmful effects to the environment and human health. In recent times, an ample range of EPs have been found in water bodies, where they can unbalance ecosystems and cause negative effects on non-target species. In addition, some EPs have shown high rates of bioaccumulation in aquatic species, thus affecting the safety and quality of seafood. The negative impacts of emerging pollutants, their wide distribution in the environment, their bioaccumulation rates, and their resistance to wastewater treatment plants processes have led to research on sustainable remediation. Remediation techniques have been recently directed to advanced biological remediation technologies. Such technologies have exhibited numerous advantages like in-situ remediation, low costs, eco-friendliness, high public acceptance, and so on. Thus, the present review has compiled the most recent studies on bioremediation techniques for water decontamination from emerging pollutants to extend the current knowledge on sustainable remediation technologies. Biological emerging contaminants, agrochemicals, endocrine-disrupting chemicals, and pharmaceutical and personal care products were considered for this review study, and their removal by bioremediation techniques involving plants, bacteria, microalgae, and fungi. Finally, further research opportunities are presented based on current challenges from an economic, biological, and operation perspective.

Current advances and research prospects for agricultural and industrial uses of microbial strains available in world collections

Microorganisms are an important component of the ecosystem and have an enormous impact on human lives. Moreover, microorganisms are considered to have desirable effects on other co-existing species in a variety of habitats, such as agriculture and industries. In this way, they also have enormous environmental applications. Hence, collections of microorganisms with specific traits are a crucial step in developing new technologies to harness the microbial potential. Microbial culture collections (MCCs) are a repository for the preservation of a large variety of microbial species distributed throughout the world. In this context, culture collections (CCs) and microbial biological resource centres (mBRCs) are vital for the safeguarding and circulation of biological resources, as well as for the progress of the life sciences. Ex situ conservation of microorganisms tagged with specific traits in the collections is the crucial step in developing new technologies to harness their potential. Type strains are mainly used in taxonomic study, whereas reference strains are used for agricultural, biotechnological, pharmaceutical research and commercial work. Despite the tremendous potential in microbiological research, little effort has been made in the true sense to harness the potential of conserved microorganisms. This review highlights (1) the importance of available global microbial collections for man and (2) the use of these resources in different research and applications in agriculture, biotechnology, and industry. In addition, an extensive literature survey was carried out on preserved microorganisms from different collection centres using the Web of Science (WoS) and SCOPUS. This review also emphasizes knowledge gaps and future perspectives. Finally, this study provides a critical analysis of the current and future roles of microorganisms available in culture collections for different sustainable agricultural and industrial applications. This work highlights target-specific potential microbial strains that have multiple important metabolic and genetic traits for future research and use.

A new cutting-edge review on the bioremediation of anaerobic digestate for environmental applications and cleaner bioenergy

Circular agriculture and economy systems have recently emerged around the world. It is a long-term environmental strategy that promotes economic growth and food security while reducing negative environmental consequences. Anaerobic digestion (AD) process has a high contribution and effective biodegradation route for bio-wastes valorization and reducing greenhouse gases (GHGs) emissions. However, the remaining massive digestate by-product contains non-fermented organic fractions, macro and/or micro-nutrients, heavy metals, and metalloids. Direct application of digestate in agriculture negatively affected the properties of the soil due to the high load of nutrients as well as the residuals of GHGs are emitted to the environment. Recycling and valorizing of anaerobic digestate is the main challenge for the sustainable biogas industry and nutrients recovery. To date, there is no global standard process for the safe digestate handling. This review described the biochemical composition and separation processes of anaerobic digestate. Further, advanced physical, chemical, and biological remediation's of the diverse digestate are comprehensively discussed. Moreover, recycling technologies such as phyco-remediation, bio-floc, and entomoremediation were reviewed as promising solutions to enhance energy and nutrient recovery, making the AD technology more sustainable with additional profits. Finally, this review gives an in-depth discussion of current biorefinery technologies, key roles of process parameters, and identifies challenges of nutrient recovery from digestate and prospects for future studies at large scale.

A BaTiO3/WS2 composite for piezo-photocatalytic persulfate activation and ofloxacin degradation

Piezoelectric fields can decrease the recombination rate of photogenerated electrons and holes in semiconductors and therewith increase their photocatalytic activities. Here, a BaTiO₃/WS₂ composite is synthesized and characterized, which combines piezoelectric BaTiO₃ nanofibers and WS₂ nanosheets. The piezo-photocatalytic effect of the composite on the persulfate activation is studied by monitoring Ofloxacin (OFL) degradation efficiency. Under mechanical forces, LED lamp irradiation, and the addition of 10 mM persulfate, the OFL degradation efficiency reaches ~90% within 75 min, which is higher than efficiencies obtained for individual BaTiO₃, WS₂, or TiO₃, widely used photocatalysts in the field of water treatment. The boosted degradation efficiency can be ascribed to the promotion of charge carrier separation, resulting from the synergetic effect of the heterostructure and the piezoelectric field induced by the vibration. Moreover, the prepared composite displays good stability over five successive cycles of the degradation process. GC-MS analysis is used to survey the degradation pathway of OFL during the degradation process. Our results offer insight into strategies for preparing highly effective piezo-photocatalysts in the field of water purification.

Sustainable microalgal biomass valorization to bioenergy: Key challenges and future perspectives

The global trend is shifting toward circular economy systems. It is a sustainable environmental approach that sustains economic growth from the use of resources while minimizing environmental impacts. The multiple industrial use of microalgal biomass has received great attention due to its high content of essential nutrients and elements. Nevertheless, low biomass productivity, unbalanced carbon to nitrogen (C/N) ratio, resistant cellular constituents, and the high cost of microalgal harvesting represent the major obstacles for valorization of algal biomass. In recent years, microalgae biomass has been a candidate as a potential feedstock for different bioenergy generation processes with simultaneous treating wastewater and CO₂ capture. An overview of the appealing features and needed advancements is urgently essential for microalgae-derived bioenergy generation. The present review provides a timely outlook and evaluation of biomethane production from microalgal biomass and related challenges. Moreover, the biogas recovery potential from microalgal biomass through different pretreatments and synergistic anaerobic co-digestion (AcoD) with other biowastes are evaluated. In addition, the removal of micropollutants and heavy metals by microalgal cells via adsorption and bioaccumulation in their biomass is discussed. Herein, a comprehensive review is presented about a successive high-throughput for anaerobic digestion (AD) of the microalgal biomass in order to achieve for sustainable energy source. Lastly, the valorization of the digestate from AD of microalgae for agricultural reuse is highlighted.

Recent Advances of Emerging Organic Pollutants Degradation in Environment by Non-Thermal Plasma Technology: A Review

Emerging organic pollutants (EOPs), including endocrine disrupting compounds (EDCs), pharmaceuticals and personal care products (PPCPs), and persistent organic pollutants (POPs), constitute a problem in the environmental field as they are difficult to completely degrade by conventional treatment methods. Non-thermal plasma technology is a novel advanced oxidation process, which combines the effects of free radical oxidation, ozone oxidation, ultraviolet radiation, shockwave, etc. This paper summarized and discussed the research progress of non-thermal plasma remediation of EOPs-contaminated water and soil. In addition, the reactive species in the process of non-thermal plasma degradation of EOPs were summarized, and the degradation pathways and degradation mechanisms of EOPs were evaluated of selected EOPs for different study cases. At the same time, the effect of non-thermal plasma in synergy with other techniques on the degradation of EOPs in the environment was evaluated. Finally, the bottleneck problems of non-thermal plasma technology are summarized, and some suggestions for the future development of non-thermal plasma technology in the environmental remediation were presented. This review contributes to our better understanding of non-thermal plasma technology for remediation of EOPs-contaminated water and soil, hoping to provide reference for relevant practitioners.

Mixed Contaminants: Occurrence, Interactions, Toxicity, Detection, and Remediation

The ever-increasing rate of pollution has attracted considerable interest in research. Several anthropogenic activities have diminished soil, air, and water quality and have led to complex chemical pollutants. This review aims to provide a clear idea about the latest and most prevalent pollutants such as heavy metals, PAHs, pesticides, hydrocarbons, and pharmaceuticals—their occurrence in various complex mixtures and how several environmental factors influence their interaction. The mechanism adopted by these contaminants to form the complex mixtures leading to the rise of a new class of contaminants, and thus resulting in severe threats to human health and the environment, has also been exhibited. Additionally, this review provides an in-depth idea of various in vivo, in vitro, and trending biomarkers used for risk assessment and identifies the occurrence of mixed contaminants even at very minute concentrations. Much importance has been given to remediation technologies to understand our current position in handling these contaminants and how the technologies can be improved. This paper aims to create awareness among readers about the most ubiquitous contaminants and how simple ways can be adopted to tackle the same.

Impact of Polymer Membrane Properties on the Removal of Pharmaceuticals

The influence of various factors on the removal efficiency of selected pharmaceuticals by membrane filtration was investigated. Several commercial polymer membranes were used for nanofiltration (NF) from various manufacturers. The studies were conducted for ibuprofen (IBF), amoxicillin (AMX), diclofenac (DCF), tetracycline (TRC), salicylic acid (SA) and acetylsalicylic acid (ASA). The influence of the structure and properties of the tested compounds on the retention coefficient and filtration rate was investigated. The influence of pH on the filtration parameters was also checked. The properties of selected membranes influencing the retention of pharmaceuticals and filtrate flux were analysed. An extensive analysis of the retention coefficients dependence on the contact angle and surface free energy was performed. It was found that there is a correlation between the hydrophilicity of the membrane and the effectiveness and efficiency of the membrane. As the contact angle of membrane increased, the flow rate of the filtrate stream increased, while the retention coefficient decreased. The studies showed that the best separation efficiency was achieved for compounds with a molecular weight (MW) greater than 300 g/mol. During the filtration of pharmaceuticals with MW ranging from 300 to 450 g/mol, the type of membrane used practically did not affect the filtration efficiency and a high degree of retention was achieved. In the case of low MW molecules (SA and ASA), a significant decrease in the separation efficiency during the process was noted.