Carbon nanotube-based electrocatalytic filtration membrane for continuous degradation of flow-through Bisphenol A

Flower-like Ni/Mn/MC microspheres derived from metal-organic frameworks for electrocatalytic degradation of ceftriaxone sodium

This study demonstrated the design and fabrication of flower-like Ni/Mn-MOFs materials, and three-dimensional ultrathin flower-like Ni/Mn/MC microspheres were fabricated by embedding metal or metal oxide nanoparticles into a porous carbon skeleton via high-temperature pyrolysis at 600 °C and used for the electrocatalytic degradation of ceftriaxone sodium. This unique ultrathin porous flower-like structure can expose more active sites, provide rapid ion/electron transfer, and improve electrocatalytic activity. Meanwhile, the excellent electrical conductivity of the carbon skeleton, as well as the rational composition and synergistic effect of the two components, can promote the generation of active radicals (•OH and •O2-) in the reaction system, which accelerates the electrochemical degradation process and improves the electrocatalytic degradation performance. The results showed that the Ni/Mn/MC-5:1 composite prepared when the molar ratio of Ni: Mn was 5:1 exhibited the best electrocatalytic degradation performance for the degradation of sodium ceftriaxone. The composites showed 98.2% degradation of ceftriaxone sodium in 120 min and maintained sound degradation after 20 cycles. Therefore, we concluded that this novel multicomponent composite has good electrocatalytic activity and stability for the degradation of antibiotic wastewater.

Bisphenol A contamination in aquatic environments: a review of sources, environmental concerns, and microbial remediation

The production of polycarbonate, a high-performance transparent plastic, employs bisphenol A, which is a prominent endocrine-disrupting compound. Polycarbonates are frequently used in the manufacturing of food, bottles, storage containers for newborns, and beverage packaging materials. Global production of BPA in 2022 was estimated to be in the region of 10 million tonnes. About 65-70% of all bisphenol A is used to make polycarbonate plastics. Bisphenol A leaches from improperly disposed plastic items and enters the environment through wastewater from plastic-producing industries, contaminating, sediments, surface water, and ground water. The concentration BPA in industrial and domestic wastewater ranges from 16 to 1465 ng/L while in surface water it has been detected 170-3113 ng/L. Wastewater treatment can be highly effective at removing BPA, giving reductions of 91-98%. Regardless, the remaining 2-9% of BPA will continue through to the environment, with low levels of BPA commonly observed in surface water and sediment in the USA and Europe. The health effects of BPA have been the subject of prolonged public and scientific debate, with PubMed listing more than 17,000 scientific papers as of 2023. Bisphenol A poses environmental and health hazards in aquatic systems, affecting ecosystems and human health. While several studies have revealed its presence in aqueous streams, environmentally sound technologies should be explored for its removal from the contaminated environment. Concern is mostly related to its estrogen-like activity, although it can interact with other receptor systems as an endocrine-disrupting chemical. Present review article encompasses the updated information on sources, environmental concerns, and sustainable remediation techniques for bisphenol A removal from aquatic ecosystems, discussing gaps, constraints, and future research requirements.

Viable remediation techniques to cleansing wastewaters comprising endocrine-disrupting compounds

Endocrine-disrupting chemicals (EDCs) have recently gained prominence as emerging pollutants due to their significant negative impacts on diverse living forms in ecosystems, including humans, by altering their endocrine systems. EDCs are a prominent category of emerging contaminants in various aquatic settings. Given the growing population and limited access to freshwater resources, their expulsion from aquatic systems is also a severe issue. EDC removal from wastewater depends on the physicochemical properties of the specific EDCs found in each wastewater type and various aquatic environments. Due to these components' chemical, physical, and physicochemical diversity, various approaches based on physical, biological, electrochemical, and chemical procedures have been developed to eliminate them. The objective of this review is to provide the comprehensive overview by selecting recent approaches that showed significant impact on the best available methods for removing EDCs from various aquatic matrices. It is suggested that adsorption by carbon-based materials or bioresources is effective at higher EDC concentrations. Electrochemical mechanization works, but it requires expensive electrodes, continual energy, and chemicals. Due to the lack of chemicals and hazardous byproducts, adsorption and biodegradation are considered environmentally friendly. When combined with synthetic biology and an AI system, biodegradation can efficiently remove EDCs and replace conventional water treatment technologies in the near future. Hybrid in-house methods may reduce EDCs best, depending on the EDC and resources.

Efficient recovery of bisphenol A from aqueous solution using K2CO3 activated carbon derived from starch-based polyurethane

Endocrine-disrupting compounds (EDCs) are increasingly polluting water, making it of practical value to develop novel desirable adsorbents for removing these pollutants from wastewater. Here, a simple cross-linking strategy combined with gentle chemical activation was demonstrated to prepare starch polyurethane-activated carbon (STPU-AC) for adsorbing BPA in water. The adsorbents were characterized by various techniques such as FTIR, XPS, Raman, BET, SEM, and zeta potential, and their adsorption properties were investigated comprehensively. Results show that STPU-AC possesses a large surface area (1862.55 m²·g^-1) and an abundance of functional groups, which exhibited superior adsorption capacity for BPA (543.4 mg·g^-1) and favorable regenerative abilities. The adsorption of BPA by STPU-AC follows a pseudo-second-order kinetic model and a Freundlich isotherm model. The effect of aqueous solution chemistry (pH and ionic strength) and the presence of other contaminants (phenol, heavy metals, and dyes) on BPA adsorption was also analyzed. Moreover, theoretical studies further demonstrate that hydroxyl oxygen and pyrrole nitrogen are the primary adsorption sites. We found that the efficient recovery of BPA was associated with pore filling, hydrogen-bonding interaction, hydrophobic effects, and π-π stacking. These findings demonstrate the promising practical application of STPU-AC and provide a basis for the rational design of starch-derived porous carbon.

Electrically conductive TiO2/CB/PVDF membranes for synchronous cross-flow filtration and solar photoelectrocatalysis

Combining photocatalysis (PC) and membrane filtration (MF) has emerged as an attractive technology for water purification, however, the water purification efficiency and membrane fouling are still challenging. Herein, we report a novel photoelectrocatalytic (PEC) membrane mediated by a ternary polyvinylidene fluoride (PVDF)-carbon black (CB)-TiO₂ composite conductive membrane synthesized by a phase inversion method assisted by the mixed surfactants of polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate (SDS). The resultant electrically conductive TiO₂/CB/PVDF membrane features a homogeneous surface with obvious pore size of 20-150 nm, a thickness ∼116 μm, and an average resistivity as low as ∼3.165 Ω∙m. The cooperation of PVP and SDS surfactants dramatically improves the organic-inorganic interactions and thus eventually enhances the porosity, stability of porous structure, mechanical stability, and conductivity and electrochemical properties of the hybrid membrane. Upon the solvent evaperation of the wellblended casting solution and the phase inversion, TiO₂/CB preferentially exist on the surface of PVDF membrane, enabling the efficient PEC degradation of organic pollutants. The synergistic coupling of TiO₂ and CB in PVDF membrane results in efficient PEC properties with bi-functional membrane antifouling and enhanced water purification in azo dyes decolorization under the stationary mode and in our lab-made continuous cross-flow PEC system, superior to those by photocatalysis and electrocatalysis. The developed synchronous MF and PEC system mediated by the conductive TiO₂/CB/PVDF membrane proves to a feasible route to improving the self-cleaning properties of the polymer membrane while simultaneously increasing the water decontaminating efficiency.

Current progress in treatment technologies for plastic waste (bisphenol A) in aquatic environment: Occurrence, toxicity and remediation mechanisms

Bisphenol-A (BPA) is a type of endocrine disrupting compound (EDC) that is being widely used in the production of polycarbonate and epoxy resins. In the last few years, human exposure to BPA has been extensively high due to the continuous increment in the Annual Growth Rate (AGR) of the BPA global market. The presence and transportation of BPA in the environment could cause serious damage to aquatic life and human health. This paper reviewed the literature on the exposure and toxicity mechanisms of BPA and advanced analytical techniques for the detection of BPA in the environment and human beings. The study indicated that BPA can cause damaging effects on numerous tissues and organs, including the reproductive system, metabolic dysfunction, respiratory system, immune system and central nervous system. On the basis of reported studies on animals, it appears that the exposure of BPA can be carcinogenic and responsible for causing a variety of cancers like ovarian cancer, uterine cancer, prostate cancer, testicular cancer, and liver cancer. This review paper focused mainly on the current progress in BPA removal technologies within last ten years (2012-2022). This paper presents a comprehensive overview of individual removal technologies, including adsorption, photocatalysis/photodegradation, ozonation/advance oxidation, photo-fenton, membranes/nanofilters, and biodegradation, along with removal mechanisms. The extensive literature study shows that each technology has its own removal mechanism and their respective limitations in BPA treatment. In adsorption and membrane separation process, most of BPA has been treated by electrostatic interaction, hydrogen boning and π-π interations mechanism. Whereas in the degradation mechanism, O* and OH* species have played a major role in BPA removal. Some factors could alter the removal potential and efficiency of BPA removal. This review paper will provide a useful guide in providing directions for future investigation to address the problem of BPA-containing wastewater treatment.

Effect of the presence of various natural organic matters on anodic oxidation of electrified carbon nanotube membrane

The widespread adoption of electrified carbon nanotube membranes (ECM) requires to better understand process effectiveness according to limiting phenomena of natural organic matters (NOMs). In this study, the influences of various NOM fractions were investigated on the oxidative degradation of Rhodamine B (RhB) in ECM. The results showed the decolorizing efficiencies of RhB in the presence of humic acid (HA) were still above 96%, while bovine serum albumin (BSA) reduced firstly and then increased the decolorizing efficiencies of RhB. The decolorizing efficiencies of RhB with alginate (AA) were over 98% at the first 15 min but decreased gradually to 76% after 150 min. These different performances of HA, BSA and AA were mainly due to their influences on the electrochemical reactivity characterization of ECM. ECM with the BSA depositing layer showed the highest exchange current density (j₀), while the AA depositing layer restrained electron-transfer activity of ECM. Cyclic voltammetry (CV) experiments showed that the partial electrooxidation of BSA would occur in ECM with its degradation product observed in the effluent. The variation of electrochemical reactivity characterization of ECM resulted into its electri-oxidation and electri-adsorption rates to be the largest with BSA, followed by AA and HA.

Endocrine disrupting chemicals (EDCs) in environmental matrices: Occurrence, fate, health impact, physio-chemical and bioremediation technology

Endocrine disrupting chemicals (EDCs) are an emerging category of toxicity that adversely impacts humans and the environment's well-being. Diseases like cancer, cardiovascular risk, behavioral disorders, autoimmune defects, and reproductive diseases are related to these endocrine disruptors. Because these chemicals exist in known sources such as pharmaceuticals and plasticizers, as well as non-point sources such as agricultural runoff and storm water infiltration, the interactive effects of EDCs are gaining attention. However, the efficiency of conventional treatment methods is not sufficient to fully remediate EDCs from aqueous environments as the occurrence of EDC bioremediation and biodegradation is detected in remediated drinking water. Incorporating modification into current remediation techniques has to overcome challenges such as high energy consumption and health risks resulting from conventional treatment. Hence, the use of advanced psychochemical and biological treatments such as carbon-based adsorption, membrane technology, nanostructured photocatalysts, microbial and enzyme technologies is crucial. Intensifying environmental and health concerns about these mixed contaminants are primarily due to the lack of laws about acute concentration limits of these EDCs in municipal wastewater, groundwater, surface water, and drinking water. This review article offers evidence of fragmentary available data for the source, fate, toxicity, ecological and human health impact, remediation techniques, and mechanisms during EDC removal, and supports the need for further data to address the risks associated with the presence of EDCs in the environment. The reviews also provide comprehensive data for biodegradation of EDCs by using microbes such as fungi, bacteria, yeast, filamentous fungi, and their extracellular enzymes.

Recent advances in electrocatalytic membrane for the removal of micropollutants from water and wastewater

The increasing occurrence of micropollutants in water and wastewater threatens human health and ecological security. Electrocatalytic membrane (EM), a new hybrid water treatment platform that integrates membrane separation with electrochemical technologies, has attracted extensive attention in the removal of micropollutants from water and wastewater in the past decade. Here, we systematically review the recent advances of EM for micropollutant removal from water and wastewater. The mechanisms of the EM for micropollutant removal are first introduced. Afterwards, the related membrane materials and operating conditions of the EM are summarized and analyzed. Lastly, the challenges and future prospects of the EM in research and applications are also discussed, aiming at a more efficient removal of micropollutants from water and wastewater.

A High Flux Electrochemical Filtration System Based on Electrospun Carbon Nanofiber Membrane for Efficient Tetracycline Degradation

In this work, an electrochemical filter using an electrospun carbon nanofiber membrane (ECNFM) anode fabricated by electrospinning, stabilization and carbonization was developed for the removal of antibiotic tetracycline (TC). ECNFM with 2.5 wt% terephthalic acid (PTA) carbonized at 1000 °C (ECNFM-2.5%-1000) exhibited higher tensile stress (0.75 MPa) and porosity (92.8%), more graphitic structures and lower electron transfer resistance (23.52 Ω). Under the optimal condition of applied voltage 2.0 V, pH 6.1, 0.1 mol L−1 Na2SO4, initial TC concentration 10 ppm and membrane flux 425 LMH, the TC removal efficiency of the electrochemical filter of ECNFM-2.5%-1000 reached 99.8%, and no obvious performance loss was observed after 8 h of continuous operation. The pseudo-first-order reaction rate constant in flow-through mode was 2.28 min−1, which was 10.53 times higher than that in batch mode. Meanwhile, the energy demand for 90% TC removal was only 0.017 kWh m−3. TC could be converted to intermediates with lower developmental toxicity and mutagenicity via the loss of functional groups (-CONH2, -CH3, -OH, -N(CH3)2) and ring opening reaction, which was mainly achieved by direct anodic oxidation. This study highlights the potential of ECNFM-based electrochemical filtration for efficient and economical drinking water purification.