Removal Of Micropollutants Research Articles

Expression of Concern: Study on the removal of organic micropollutants from aqueous and ethanol solutions by HAP membranes with tunable hydrophilicity and hydrophobicity (Chemosphere, Vol. 174, May 2017, Pages 380–389)

Expression of Concern: Study on the removal of organic micropollutants from aqueous and ethanol solutions by HAP membranes with tunable hydrophilicity and hydrophobicity (Chemosphere, Vol. 174, May 2017, Pages 380–389)

Characterization of a hyperbolic vortex plasma reactor for the removal of aqueous phase micropollutants

The present study focuses on the characterization of a hyperbolic vortex plasma reactor through the comparison of various plasma-atmospheric regimes for the production efficiency of reactive nitrogen (RNS) and reactive oxygen (ROS) species. The research also explores effectiveness in the removal of micropollutants, including pharmaceuticals and per- and polyfluoroalkyl substances (PFAS). The technology includes several degradation mechanisms, such as advanced oxidation, ultraviolet photolysis, ozonation, electrolysis, and shockwave water purification, without the need for additional chemicals. Our results indicate that the plasma of bipolar or ‘flashover’ mode is notably more effective and efficient than both positive or negative polarity. Through the testing of various energy levels, it has been demonstrated that higher energy plasma yields lower efficiency but necessitates shorter treatment times compared to lower energy treatment. When plasma is produced under ambient atmosphere, water chemical properties change significantly in comparison to treatment under argon (Ar) or nitrogen (N2) due to the presence of both oxygen and N2 molecules. In a N2 atmosphere, the predominant formation is of RNS due to the chemical reactivity of N2 exited states, whereas under Ar atmosphere, predominantly ROS are generated. Notable advantages of this technology are its scalability and its low energy requirements. The scalability of the technology involves increasing the size of the reactor, the power and electrode count.

Immobilization of Bi2WO6 on Polymer Membranes for Photocatalytic Removal of Micropollutants from Water - A Stable and Visible Light Active Alternative.

In this work, bismuth tungstate Bi2WO6 is immobilized on polymer membranes to photocatalytically remove micropollutants from water as an alternative to titanium dioxide TiO2. A synthesis method for Bi2WO6 preparation and its immobilization on a polymer membrane is developed. Bi2WO6 is characterized using X-ray diffraction and UV-vis reflectance spectroscopy, while the membrane undergoes analysis through scanning electron microscopy, X-ray photoelectron spectroscopy, and degradation experiments. The density of states calculations for TiO2 and Bi2WO6, along with PVDF reactions with potential reactive species, are investigated by density functional theory. The generation of hydroxyl radicals OH• is investigated via the reaction of coumarin to umbelliferone via fluorescence probe detection and electron paramagnetic resonance. Increasing reactant concentration enhances Bi2WO6 crystallinity. Under UV light at pH 7 and 11, the Bi2WO6 membrane completely degrades propranolol in 3 and 1 h, respectively, remaining stable and reusable for over 10 cycles (30 h). Active under visible light with a bandgap of 2.91eV, the Bi2WO6 membrane demonstrates superior stability compared to a TiO2 membrane during a 7-day exposure to UV light as Bi2WO6 does not generate OH• radicals. The Bi2WO6 membrane is an alternative for water pollutant degradation due to its visible light activity and long-term stability.

Biochar from co-pyrolysis of biological sludge and sawdust in comparison with the conventional filling media of vertical-flow constructed wetlands for the treatment of domestic-textile wastewater.

A biochar from co-pyrolysis of a mixture of sawdust and biological sludge (70/30, w/w), providing a high environmental compatibility in terms of water leachable polycyclic aromatic hydrocarbons and inorganic elements, together with a remarkable surface area (389 m2/g), was integrated into laboratory-scale vertical-flow constructed wetlands (VF-CWs), planted with Phragmites australis and unplanted. Biochar-filled VF-CWs have been tested for 8 months for the refining of effluents from the tertiary clariflocculation stage of a wastewater treatment plant operating in a mixed domestic-industrial textile context, in comparison with systems filled with gravel. VF-CW influents and effluents were monitored for chemical oxygen demand (COD), nitrogen and phosphorus cycles, and absorbance values at 254 and 420 nm, the latter as rapid and reliable screening parameters of the removal of organic micropollutants containing aromatic moieties and/or chromophores. Biochar-based systems provided a statistically significant improvement in COD (Δ = 22%) and ammonia (Δ = 35%) removal, as well as in the reduction of UV-Vis absorbance values (Δ = 32-34% and Δ = 28% for 254 and 420 nm, respectively), compared to gravel-filled microcosms. The higher removal of organic was mainly attributed to the well-known adsorption properties of biochars, while for nitrogen the biological mechanisms seem to play a predominant role.

Transformative Removal of Aqueous Micropollutants into Polymeric Products by Advanced Oxidation Processes.

This perspective presents the latest advancements in selective polymerization pathways in advanced oxidation processes (AOPs) for removal of featured organic pollutants in wastewater. In radical-based homogeneous reactions, SO4• --based systems exhibit superior oxidative activity toward aromatics with electron-donating substituents via single electron transfer and radical adduct formation (RAF). The produced organic radical cations subsequently undergo coupling and polymerization reactions to produce polymers. For •OH-based oxidation, metal ions facilitate the production of monomer radicals via RAF. Additionally, heterogeneous catalysts can mediate both coupling and polymerization reactions via persulfate activation without generating inorganic radicals. Metal-based catalysts will mediate a direct oxidation pathway toward polymerization. In contrast, carbon-based catalysts will induce coupling reactions to produce low-molecular-weight oligomers (≤4 units) via an electron transfer process. In comparison to mineralization, polymerization pathways remarkably reduce peroxide usage, quickly separate pollutants from the aqueous phase, and generate polymeric byproducts. Thus, AOP-driven polymerization systems hold significant promise in reducing carbon emission and realizing carbon recycling in water treatment processes.

Characterization of Ceramic Beads for the Removal of Organic Micropollutants from Wastewater and Prediction of Their Adsorption Properties by In Silico Quantitative Structure–Adsorption Relationship Modeling

Characterization of Ceramic Beads for the Removal of Organic Micropollutants from Wastewater and Prediction of Their Adsorption Properties by In Silico Quantitative Structure–Adsorption Relationship Modeling

Non-radical activation of low additive periodate by carbon-doped boron nitride for acetaminophen degradation: Significance of high-potential metastable intermediates

Metal-free environmental-friendly and cost-effective catalysts for periodate (PI) activation are crucial to popularize their application for micropollutant removal in water. Herein, we report that carbon-doped boron nitride (C-BN) can efficiently activate PI to degrade acetaminophen under very low oxidant doses (40 μM) and over a relatively wide pH range (3−9). As expected, the significant reduction in periodate addition is likely to be due to the higher chemical utilization efficiency achieved by a non-radical oxidation pathway. This involved two main mechanisms, the electron transfer process mediated by the high-potential metastable C-BN-900-PI* complex and singlet oxygen. In this case, the CO groups and defects on the C-BN surface were identified as key active sites for PI activation. Notably, the prepared C-BN-900 had good cycling performance and the degradation efficiency is recovered after simple annealing. The existence of HCO3− and HA significantly inhibited the reaction, whereas Cl−, SO42−, and NO3− had little effect on the degradation of ACE. Overall, this study provides a new alternative method to regulate the non-radical pathway of boron nitride/periodate system.

Highly efficient micropollutant decomposition by ultrathin amorphous cobalt-iron oxide nanosheets in peroxymonosulfate-mediated membrane-confined catalysis

Applications of advanced oxidation processes (AOPs) in water treatment require addressing technological challenges such as developing low-cost techniques for nanocatalyst synthesis, overcoming mass transfer limitations, and enhancing the yield of reactive oxygen species (ROS). This study employs a simple sodium borohydride (NaBH4)-based reduction technique for synthesizing ultrathin amorphous cobalt-iron oxide nanosheets (A/Co3-Fe ONS) to activate peroxymonosulfate (PMS). These nanosheets were found to outperform crystalline nanosheets due to their abundant reactive sites, oxygen vacancies, and capability to produce ROS through O–O and S–O bond cleavage. Due to the nanoconfinement effect, converting A/Co3-Fe ONS into a lamellar membrane significantly enhances reactivity and efficacy (1290 times) compared to batch PMS-mediated AOP reactors. Quenching experiments, solid-state and solution-based electron paramagnetic resonance (EPR) spectroscopy facilitated delineation of the reaction mechanisms involving both radical and nonradical pathways. Finally, the A/CoFeOx membrane achieved efficient removal (>95 %) of various organic micropollutants (OMPs), ultrafast destruction (318 ms), and excellent stability (48 h) through redox-recycling facilitated by the redox-potential difference and oxygen vacancies. This strategy offers a low-temperature cost-effective alternative and may be considered for scale-up in water treatment.

Hydroponic materials improve organic micropollutant removal in vertical flow constructed wetlands treating wastewater

Unconventional substrata like activated carbon or clay beads can enhance micropollutant removal in constructed wetlands. However, hydroponic materials widely used in horticulture have not yet been investigated for their potential to remove micropollutants. In addition, potential effect of plant species other than reeds on micropollutant removal has not been sufficiently investigated. Therefore, a nature-based, post-treatment technology called improved vertical flow constructed wetlands (CW) with hydroponic (H) materials (CWH) was designed by employing cocopeat and mineral with ornamental plant species syngonium and periwinkle. A mesocosm CWH system was tested in a climate-controlled greenhouse for 550 days for its potential to remove frequently found micropollutants in wastewater, namely sulfamethoxazole, trimethoprim, diclofenac, erythromycin, carbamazepine, pyrimethanil, tebuconazole, pymetrozine, atrazine and DEET from wastewater effluent. The main focus was to understand the contribution of sorption, microbial degradation and phytoremediation on the removal of those micropollutants. It was found that cocopeat showed a capacity for sorbing micropollutants, ranging between 80 and 99% of the compounds added while less than 10% sorption was observed for mineral wool. Additionally moderate to high biological removal (25–60 μg of compound/kg dry weight of substratum/day) for most of the studied compounds was observed in all the cocopeat biotic groups. Furthermore, it could be stated that plants appear not to be an important factor for micropollutant removal. The observed differences in removal between the cocopeat and mineral wool systems could be explained by the difference in physico-chemical properties of the substrata, where cocopeat has a higher water holding capacity, moisture content, nutrient and organic matter content, and a higher intraparticle porosity and surface area. This study revealed notable removal of persistent and mobile micropollutants in cocopeat CWH, namely carbamazepine (80–86%) and diclofenac (97–100%). These results demonstrate the potential beneficial use of hydroponic materials as substratum in more advanced constructed wetlands designed to remove micropollutants.

Corrigendum: Characterisation of two wood-waste and coffee bean husk biochars for the removal of micropollutants from water

Corrigendum: Characterisation of two wood-waste and coffee bean husk biochars for the removal of micropollutants from water

Removal characteristics of 53 micropollutants during ozonation, chlorination, and UV/H2O2 processes used in drinking water treatment plant

The removal of 53 emerging micropollutants (MPs), including 10 per- and polyfluorinated substances (PFASs), 25 pharmaceuticals and personal care products (PPCPs), 7 pesticides, 5 endocrine disrupters (EDCs), 3 nitrosamines, and 3 taste and odor compounds (T&Os), by chlorination, ozonation, and UV/H2O2 treatment was examined in deionized water and surface waters used as the raw waters in drinking water treatment plants (DWTPs) in South Korea. The UV/H2O2 treatment was effective in the removal of most MPs, whereas chlorination was selectively effective for 19 MPs, including EDCs (>70 %). MPs containing aromatic ring with electron-donating functional group, or primary and secondary amines were effectively removed by chlorination immediately upon reaction initiation. The removal of MPs by ozonation was generally lower than that of the other two processes at a low ozone dose (1 mg L−1), but higher than chlorination at a high ozone dose (3 mg L−1), particularly for 16 MPs, including T&Os. Compared in deionized water, the removals of MPs in the raw water samples were lower in all three processes. The regression models predicting the rate constants (kobs) of 53 MPs showed good agreement between modeled and measured value for UV/H2O2 treatment (R2 = 0.948) and chlorination (R2 = 0.973), despite using only dissolved organic carbon (DOC) and oxidant concentration as variables, whereas the ozonation model showed a variation (R2 = 0.943). Our results can provide the resources for determining which oxidative process is suitable for treating specific MPs present in the raw waters of DWTPs.

Integrated and Hybrid Processes for the Treatment of Actual Wastewaters Containing Micropollutants: A Review on Recent Advances

The global concern regarding the release of micropollutants (MPs) into the environment has grown significantly. Considerable amounts of persistent micropollutants are present in industrial discharges. Depending solely on a singular treatment approach is inadequate for the effective removal of MPs from wastewater due to their complex composition. The performance of different treatment methods to meet the discharge standards has been widely studied. These efforts are classified as hybrid and sequential processes. Despite their adequate performance, the optimization and industrial application of these methods could be challenging and costly. This review focuses on integrated (sequential) and hybrid processes for MP removal from actual wastewater. Furthermore, to provide a thorough grasp of the treatment approaches, the operational conditions, the source of wastewater containing MPs, and its characteristics are detailed. It is concluded that the optimal sequence to achieve the removal of MPs involves biological treatment followed by an advanced oxidation process (AOP) with a final passage through an activated carbon column. To refine this process further, a membrane unit could be added based on the desired effluent quality. Nevertheless, considering practical feasibility, this study identifies specific areas requiring additional research to implement this integrated treatment strategy effectively.

From PET bottle waste to enzyme support for removal of estrogens from wastewaters

Recycling poly(ethylene terephthalate) disposables into electrospun functional membranes creates new opportunities for pollution reduction. In this study, two types of electrospun membranes made of poly(ethylene terephthalate) (PET) recycled from bottles and PET recycled from recycled bottles (rPET) were utilized in order to produce four types of biosystems with immobilized laccase for the removal of synthetic hormones micropollutants from wastewater. The enzyme was adsorbed onto the fibers directly or after a prior 24 h treatment with 10% glutaraldehyde. Obtained removal efficiency of 17α-ethynylestradiol from aqueous systems was in a range of 71% to 85%, depending on the type of PET utilized for the fabrication of the membranes and the way of laccase immobilization. Moreover, fabricated biosystems showed highly improved storage stability of 72% to 85% compared to only 55% activity exhibited by free laccase after 20 days of storage. Immobilization of the laccase on the PET-based fibrous substrates also increased their thermal stability after 2 h at 50 °C with preserved activity in a range of 27% to 55%, compared to only 5% registered for the free enzyme. Produced biosystems exhibited high reusability and the activity of the enzyme remains over 60% after seven catalytic cycles for all tested samples, with 79% activity after eight cycles obtained for the enzyme immobilized on PET membranes modified with glutaraldehyde prior to immobilization of laccase. The presented approach has been proven to have great potential as a sustainable tool for the enzymatic removal of synthetic hormones from wastewaters showing superior properties compared to the utilization of the enzyme in its basic form.

Nanocomposite PVDF/TiO2 Photocatalytic Membranes for Micropollutant Removal in Secondary Effluent

In this study, a mixed-matrix method was used to prepare PVDF polymeric membranes with different amounts of TiO2 P25 photocatalyst embedded, which were employed in filtration processes in the presence of UV radiation (LED, peak emission at 375 nm) to eliminate two aqueous micropollutants (MPs) used as model compounds (venlafaxine and metoprolol). The obtained membranes were characterized to gain insights into their texture, morphology, composition, and other catalyst-related properties that could affect the photocatalytic filtration process. For that purpose, N2 adsorption–desorption, contact angle, SEM-EDX, thermal analysis, FTIR, XPS, UV-vis DRS, and PL spectroscopy were used. Filtration tests were carried out in continuous mode using a dead-end filtration cell to evaluate the performance of the prepared membranes in removing the selected MPs. Experiments were performed both in ultrapure water and a secondary effluent from a municipal wastewater treatment plant. It was found that the synthesized membranes could effectively remove the target MPs in ultrapure water, achieving up to 99% elimination. Such process performance decreased drastically in the secondary effluent with removals below 35%. Carbonate/bicarbonate ions in the secondary effluent were identified as the main scavenging substances. Thus, after the partial removal of carbonate/bicarbonate ions from the secondary effluent, the removal of MPs achieved was above 60%.

Generation of •OH and intermediate manganese species for the efficient removal of micropollutants via photocatalysis of permanganate by indium oxide

Activation of permanganate (Mn(VII)) by generating intermediate manganese species (Mnint, i.e., Mn(V) and Mn(III)) has been demonstrated to be an efficient way to enhance the oxidative ability of Mn(VII). In this work, it was found that the addition of indium oxide (In2O3) could significantly enhance the visible light response of Mn(VII) (Vis/In2O3/Mn(VII)) by selecting flumequine (FLU) as a representative compound. The presence of In2O3 enhanced the degradation of FLU by the Vis/Mn(VII) process with the pseudo-first-order rate constant increasing by around 30 folds. Intermediate Mnint (Mn(V) and Mn(III)) and hydroxyl radicals (•OH) were identified as the major oxidants in the Vis/In2O3/Mn(VII) process, and •OH outcompeted that of Mnint under alkaline conditions. The scavenge of photogenerated e- by Mn(VII) played a critical role in the generation of Mnint, while the reaction of photogenerated h+ with H2O contributed to the generation of •OH. The degradation efficiency of FLU showed a negative relationship with the increase of solution pH, likely due to the electrostatic repulsion between the deprotonated FLU and negatively charged In2O3 surfaces. Increasing Mn(VII) or In2O3 dosages enhanced the degradation of FLU by elevating the concentrations of reactive species. The presence of chloride, bicarbonate, and humic acid slightly inhibited FLU degradation by the Vis/In2O3/Mn(VII) process, due to their competitive scavenging of reactive species. Totally 14 oxidation products were identified during FLU oxidation by the Vis/In2O3/Mn(VII) process, and they were likely generated via hydroxylation, defluorination, dealkylation/decarboxylation/deamination, ring-opening, or oxidation pathways. Good stability and reusability of the In2O3 catalyst were obtained. This work proposed a new activation pathway for Mn(VII) and provided a novel approach for the treatment of emerging contaminants in aqueous environments.

Synthesis and characterization of the magnetic chitosan/zinc oxide nanocomposite: an efficient magnetic adsorbent for removal of harmful aromatic micropollutants from wastewater

In this work, a magnetic chitosan/zinc oxide nanocomposite (CS/ZnO-Fe3O4) was fabricated for efficient adsorptive removal of harmful aromatic micropollutants, including Cephalexin (CFX) antibiotic and Eosin B (EB) dye from wastewater samples. To maximize the adsorption efficiency of the CS/ZnO-Fe3O4, the adsorption process was first modeled and statistically optimized by using the response surface methodology based on central composite design (RSM-CCD). The results demonstrated that the maximum removal efficiency of the adsorbent for CFX and EB was 98.87% and 99.08%, respectively. Also, the adsorption isotherms, kinetics, and thermodynamics were also studied in detail under the optimum conditions. The results indicated that the adsorption equilibrium data was fit well with the Langmuir isotherm model, which indicated monolayer adsorption via chemisorption process. The Langmuir maximum adsorption capacity (Qmax) was 81.38 mg g−1 and 144.4 mg g−1 for CFX and EB, respectively. The adsorption kinetic was followed by the pseudo-second-order kinetic model, and the thermodynamic studies showed that the adsorption process was endothermic and spontaneous, as well as that adsorption entropy was also increased during the process. Also, the main adsorption mechanism was considered to be based on H-bonding, n-π, and electrostatic interactions. The regeneration experiments indicated that the spent adsorbent was easily regenerated by NaOH solution (0.1 mol L−1) and reused for subsequent cycles without a significant decrease in its performance, so that removal efficiency remained about 90% at the fourth cycle. Overall, the results indicated that CS/ZnO-Fe3O4 could be used as a promising adsorbent for the efficient removal of aromatic micropollutants from wastewater.

Continuous Removal of Organic Micropollutants from Municipal Treated Effluents and Studying Kinetics of Removal of Methylene Blue as a Model Micropollutant Component in Batch and Continuous Flow Systems

Continuous Removal of Organic Micropollutants from Municipal Treated Effluents and Studying Kinetics of Removal of Methylene Blue as a Model Micropollutant Component in Batch and Continuous Flow Systems

Ensuring safety standards in sewage sludge-derived biochar: Impact of pyrolysis process temperature and carrier gas on micropollutant removal

The application of sewage sludge to agricultural land is facing increasing restrictions due to concerns about various micropollutants, including polycyclic aromatic hydrocarbons (PAHs), dioxins and furans (PCDD/Fs), polychlorinated biphenyls (PCBs), per- and poly-fluoroalkyl substances (PFAS), and heavy metals (HMs). As an alternative approach to manage this residue, the use of pyrolysis, a process that transforms sludge into biochar, a carbon-rich solid material, is being explored. Despite the potential benefits of pyrolysis, there is limited data on its effectiveness in removing micropollutants and the potential presence of harmful elements in the resulting biochar. This study aims to evaluate the impact of the temperature and the use of a carrier gas (N2) during a two-stage pyrolysis and cooling on micropollutant removal. Pilot-scale tests showed that a higher temperature (650 °C) and the use of a carrier gas (0.4 L/min N2) during the pyrolysis and the cooling process led to a reduction of PAHs, PCDD/Fs, PCBs and PFAS below their detection limits. As such, the generated biochar aligns with the guidelines set by the International Biochar Initiative (IBI) and the European Biochar Certificate (EBC) for all micropollutants, except for zinc and copper. Additional investigation is required to determine whether the micropollutants undergo destruction or transition into other pyrolysis end-products, such as the gas or liquid phase.

Methods for eliminating micropollutant from wastewater: A review

The amount of suspended solid and medicinal micropollutants, such as fungicides, personal care products, contraceptive medications, antibiotics and aromatic hydrocarbons are increasing daily and has reached an alarming level. The micropollutant present in wastewater must be treated before its release because it forms adverse effect on mortal health. Because some harmful micropollutants are incredibly difficult to remove from WWTPs because of their nonbiodegradability, poor adsorption capability, complex nature and traditional wastewater treatments are precious or insufficient for decontamination. For the micropollutant declination some of the conventional physicochemical has been used. The use of powdered activated carbon (PAC) for water purification has been proven to be effective without harming the environment. Advanced oxidation technologies (AOTs), typically applied after natural processes have recently emerged as effective tertiary treatments for the withdrawal of micropollutants at high concentrations. Various methods have been developed and studied for the removal of these micropollutants from wastewater. This review aims to provide a comprehensive overview of the different methods employed, including physical, chemical, and biological processes, highlighting their effectiveness and limitations in micropollutant removal. As well as improving treatment efficiency, they can also remove any accumulation of dangerous byproducts produced during treatment.

Polymer–Zeolite Composites: Synthesis, Characterization and Application

Although the potential of natural minerals for purification of liquid radioactive wastes (LRW) from radionuclides has been widely studied, the use of hybrid polymer composites made of zeolite is still rather scarce. This article reports on the preparation of zeolite-based hybrid polymer composites using the in situ polymerization technique in the body of mineral matrix and its intercalated with copper ferrocyanide (CuFC) forms. This hybrid polymer composites have shown unique and enhanced properties for the removal of micropollutants from wasted water as compared to the individual mineral. The change in conventional properties of two mixed minerals, such as zeolite and bentonite, and their intercalated with CuFC forms were probed using techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), Mössbauer spectroscopy (MS) and FT-IR analysis. The totality of analysis showed a coexistence of intercalated and percolated zeolite phases. The hybrid polymer composites exhibited both adsorption and ion-exchange properties in the removal of 134,137Cs+, 57,60Co2+ and 85Sr2+ radionuclides from LRW.