Treatment Of Emerging Contaminants Research Articles

Membrane-based technologies for removing emerging contaminants in urban water systems: Limitations, successes, and future improvements

Emerging contaminants (ECs) have been continuously discovered in recent years, posing high risks to human health and environmental safety. Due to their characteristics, such as environmental persistence and bioaccumulation, ECs have severe and often hidden hazards, necessitating effective control measures. Membrane-based technologies possess satisfactory feasibility in the treatment of ECs, which are considered green, efficient, and economically beneficial. Membrane technologies such as membrane separation and membrane bioreactor (MBR) treatment can efficiently remove some ECs. With the rapid development of materials science, membrane-based coupled technologies such as catalytic membranes and adsorption membranes have also achieved significant success, offering effective solutions for the treatment of refractory organic contaminants. This article systematically elucidated the effectiveness, progress, and shortcomings of membrane-based technologies in the field of ECs treatment in recent years. The trends of membrane-based technologies in the field of removal of ECs in the past two decades were described in detail, with a bibliometric analysis. The management situation of newly discovered microplastics (MPs) and antibiotic resistance genes (ARGs) was also discussed. This review provided reasonable insights into the application of membrane-based technologies in the removal of ECs and offers suggestions for future research directions.

Enhanced Fenton-like process over Cu/L(+)-ascorbic acid co-doping mesoporous silica for toxicity reduction of emerging contaminants

Effective removal of emerging contaminants (ECs) to minimize their impacts on human health and the natural environment is a global priority. For the removal of ECs in water, we fabricated a seaweed spherical microsphere catalyst with Cu cation-π structures by in situ doping of Cu species and ascorbic acid in mesoporous silica (Cu-C-MSNs) via a hydrothermal method. The results indicate that bisphenol A (BPA) is substantially degraded within 5 min under natural conditions, with its biological toxicity considerably weakened. Moreover, industrial wastewater could also be effectively purified by Cu-C-MSNs/H2O2 system. The presence of metal sites and the complexation of ECs via cation-π interaction and π-π stacking on the catalyst surface were directly responsible for the polarization distribution of electrons, thus activating H2O2 and dissolved oxygen (DO). The removal of contaminants could be attributed primarily to 1) the activation of H2O2 into •OH to attack the contaminants and 2) self-cleavage because of the transfer of electrons from the contaminants to the catalysts. This study provides an innovative solution for the effective treatment of ECs and has positive implications for easing global environmental crises.

Occurrence, removal, and risk assessment of emerging contaminants in aquatic products processing sewage treatment plants.

Emerging contaminants (ECs) in aquatic environments have attracted attention due to their wide distribution and potential ecotoxicities. Sewage treatment plants (STPs) are proven to be the major source of ECs in the aquatic environment, while there remains insufficient understanding of the removal and risk assessment of ECs in STPs. Here, we clarified the degradation and risk impact of 13 ECs in two aquatic product processing sewage treatment plants (APPSTPs) along the southeast coast of China. The concentrations of ECs followed the order: endocrine-disrupting chemicals (1877.85-15,398.02ng/L in influent, 3.37-44.47ng/L in effluent) > > sulfonamide antibiotics (SAs, 75.14-906.19ng/L in influent, 1.14-15.33ng/L in effluent) > pharmaceutical and personal care products (PPCPs, 44.47-589.93ng/L in influent, 2.54-34.16ng/L in effluent) ≈ fluoroquinolone antibiotic (54.76-434.83ng/L in influent, 10.75-32.82ng/L in effluent) > other antibiotics (16.21-51.96ng/L in influent, 0.68-6.17ng/L in effluent). Moreover, the concentrations of PPCPs (decreased by 55.33-87.65% in peak fishing season) and antibiotics (increased by 44.99% in peak fishing season) were affected by fishing activities. In particular, the sequencing batch reactor (SBR) process had a better removal effect than the anaerobic-anoxic-oxic (A2/O) process on the treatment of some contaminants (e.g., norfloxacin and nonylphenol). Risk evaluations of ECs demonstrated that nonylphenol and SAs were at high- and low-risk states, respectively. Overall, our results provide important information for the degradation treatment of ECs, which is essential for pollutant management policy formulation.

Fate of emerging contaminants in a sequencing batch reactor and potential of biological activated carbon as tertiary treatment for the removal of persisting contaminants

The study aims to understand the occurrence and removal of 20 emerging contaminants (ECs) in each unit process of a sequencing batch reactor-based wastewater treatment plant (WWTP) and explore the potential of biological activated carbon (BAC) for the treatment of residual ECs and organic matter in the secondary effluent. Analgesic-acetaminophen, anti-inflammatory drug-ibuprofen, and stimulant-caffeine were detected at high concentrations in the influent. Most of the removal was observed in the biological treatment stage in the SBR basins. The mass load of the ECs was 2.93 g/d in the secondary effluent and 0.4 g/d in the final sludge, while the total removal of the mass load of ECs till the secondary treatment stage was 93.22%. 12 of the 20 ECs were removed by more than 50%, while carbamazepine (negative removal), sulfamethoxazole, and trimethoprim were removed by less than 20%. As a polishing step and to remove residual ECs, two BAC units were studied for 11,000 bed volumes (324 days). Packed column studies on granular activated carbon were conducted, and GAC development to BAC was monitored. SEM and FTIR were used to confirm and characterize the BAC. The BAC appeared to be more hydrophobic than the GAC. The BAC removed 78.4% and 40% of the dissolved ECs and organic carbon at an optimum EBCT of 25 min. Carbamazepine, sulfamethoxazole, and trimethoprim were removed by 61.5, 84, and 52.2%, respectively. Parallel column tests revealed adsorption as an important mechanism for the removal of positively charged compounds. The results indicate that the BAC is an effective tertiary/polishing technique for removing organic and micropollutants in the secondary wastewater effluent.

Recent Advancements in the Treatment of Emerging Contaminants Using Activated Persulfate Oxidation Process

Emerging contaminants (ECs) usually refer to pesticides, polycyclic aromatic hydrocarbons (PAHs), dioxins, personal care products, cosmetics, and medications. Due to the strong demand and quick growth of these businesses, the ECs have continuously been found in alarming amounts in groundwater, surface water, and wastewater. These ECs provide a significant non-esthetic threat to the ecosystem as a whole and can cause significant non-esthetic contamination when released into the aquatic environment. The conventional wastewater treatment techniques such as activated sludge, membrane filtration, coagulation, adsorption, and ozonation showed ECs removal performance to a certain extent. In turn, numerous emerging advanced oxidation processes (AOPs), especially activated persulfate oxidation, have garnered a huge amount attention due to their outstanding performance in the remediation of ECs. This article presents a systematic and critical review of electro, sono and thermal activation of persulfate for the treatment of ECs. The effect of key parameters such as electrode materials, solution pH, persulfate concentration, current density, and temperature on electro, sono- and thermal-activated degradation of ECs was discussed. The possible reaction mechanism of ECs degradation was also elucidated in detail. It was closed with a note on the situation now and the future course of electro, sono and thermal activation in ECs degradation applications. Experiments performed in recent studies show that with the aid of persulfate in electro activation, the removal efficiency of chemical oxygen demand can be achieved up to 72.8%. Persulfate activated by sono shows 100% removal efficiency of 1,1,1-trichloroethane and sulfamethoxazole. While for thermal activation of persulfate, 100% removal efficiency of carbamazepine, atrazine and sulfamethazine was achieved. All these vital shreds of evidence are substantial enough to picture the negative impact of ECs on the environment.

Exploring degradation properties and mechanisms of emerging contaminants via enhanced directional electron transfer by polarized electric fields regulation in Fe-N4-Cx

Heterogeneous catalysis offers an opportunity to overcome the low efficiency and secondary pollution limitations of emerging contaminants (ECs) purification technologies, but it is still challenging to regulate electron directed transport for achieving high catalysis efficiency and selectivity due to insufficient understanding of the electron transfer pathways and behavioral mechanisms during its catalysis. Here, by tuning the defects of the C-N coordination of the support, the polarized electric field (PEF) characteristics are changed, which in turn affects the electron transport behavior. The results show that the charge offset on Fe-N4-Cx forms a PEF, which will induce directional electron transport. After the quantitative structure-activity relationship (QSAR) fitting analysis, the greater the degree of C-N defects, the higher the intensity of the PEF, which in turn enhances the electron transport and promotes the catalytic behavior. In addition, the surface pyrrole N site can adsorb enrofloxacin (ENR) and enrich it on the surface. This can reduce the transport distance of reactive oxygen species (ROS) to synergize catalysis and adsorption, resulting in rapid degradation of ECs. Combined with liquid chromatograph mass spectrometer (LC-MS) results and theoretical calculations, five degradation pathways of ENR were speculated, mainly including the oxidation of piperazine and the cleavage of the quinolone ring. This work proposes a novel PEF regulation strategy and explores its mechanism for safe treatment of ECs.

Recent trends in treatment technologies of emerging contaminants

AbstractIn the recent years a group of contaminants, known collectively as emerging contaminants (ECs), have attracted considerable attention due to their widespread in the environment, and lack of knowledge on their impacts on ecosystem and human health. This review gives an overview on the sources, impacts, and conventional treatment technologies of ECs and an in‐depth review of the literature on the state‐of‐the‐art treatment technologies and their performance in the removal of ECs from water sources and drinking water. A careful statistical analysis of the number of publications on the different treatment technologies of ECs was performed to identify the hot spots in this research area. Conventional treatment technologies are not able to remove ECs sufficiently. The discharge of raw or partially treated wastewater is the main source of ECs in the environment. The research in recent years is focusing on using advanced treatment process (AOPs), followed by adsorption and membrane technologies. From a technical point of view, AOPs surpass other treatment technologies as they can completely eradicate ECs without the generation of side products. Developing efficient, green, and cost‐effective materials to be used as adsorbents, photocatalysts, membranes, or membrane fillers, is one of the main research trends nowadays. Combined AOPs based on exploiting solar light, ultrasound and electrochemistry are gaining growing interest and show high potential for the treatment of ECs.