Biochar-based fixed filter columns for water treatment: A comprehensive review.

Biochar used in fixed filter columns (BFCs) has garnered significant attention for its capabilities in material immobilization and recovery, filtration mechanisms, and potential for scale-up, surpassing the limitations of batch experiments. This review examines the efficacy of biochar in BFCs, either as the primary filtering material or in combination with other media, across various wastewater treatment scenarios. BFCs show high treatment efficiency, with an average COD removal of 80 % ±15.3 % (95 % confidence interval: 72 %, 86 %). Nutrient removal varies, with nitrogen-ammonium and phosphorus-phosphate removal averaging 71 ± 17.1 % (60 %, 80 %) and 57 % ± 25.6 % (41 %, 74 %), respectively. Pathogen reduction is notable, averaging 2.4 ± 1.12 log10 units (1.9, 2.9). Biochemical characteristics, pollutant concentrations, and operational conditions, including hydraulic loading rate and retention time, are critical to treatment efficiency. The pyrolysis temperature (typically 300 to 800 °C) and duration (1.0 to 4.0 h) influence biochar's specific surface area (SSA), with higher temperatures generally increasing SSA. This review supports the biochar application in wastewater treatment and guides the design and operation of BFCs, bridging laboratory research and field applications. Further investigation is needed into biochar reuse as a fertilizer or energy source, along with research on BFC models under real-world conditions to fully assess their efficacy, service life, and costs for practical implementation.

Revisiting triplet state dissolved organic matter (3DOM⁎): Advances in probes, photoreactivity, and environmental implications.

Triplet-state dissolved organic matter (3DOM⁎) plays a critical role in the photodegradation of organic pollutants in aquatic environments. This review offers a comprehensive overview of 3DOM⁎, focusing on monitoring methods using various probes, formation mechanisms, and photoreactivity. Traditional probes, such as 2,4,6-trimethylphenol (TMP) and sorbic acid, are widely used, while novel probes promise improved accuracy and sensitivity. The E2:E3 ratio emerges as a promising indicator for 3DOM⁎ due to its simplicity and correlation with photoreactivity, though further validation is needed to confirm its broader applicability. This review highlights the higher photoreactivity of DOM with low molecular weight, low aromaticity, and autochthonous sources, although DOM with contrasting features can also show significant photoreactivity. The presence of inorganic ions and nanomaterials significantly influences 3DOM⁎'s degradation capacity, demonstrating complex interactions with surrounding species. Additionally, the review underscores the importance of various environmental factors, including light source and DOM concentration, in affecting the photodegradation rates of contaminants. Recent literature suggests that future research should focus on developing new probes to capture different aspects of 3DOM⁎, exploring the synergistic effects of plastic leachate, and investigating the role of co-existing ions and nanomaterials on 3DOM⁎ activity. Employing machine learning (ML) techniques to predict 3DOM⁎-related parameters from easily measurable DOM descriptors presents an exciting research avenue. Enhanced understanding of 3DOM⁎ can lead to more effective strategies in wastewater treatment and environmental remediation.

Sources, environmental fate, and impacts of microplastic contamination in agricultural soils: A comprehensive review.

The pervasive presence of microplastics has emerged as a pressing global environmental concern, posing threats to food security and human health upon infiltrating agricultural soils. These microplastics primarily originate from agricultural activities, including fertilizer inputs, compost-based soil remediation, irrigation, and atmospheric deposition. Their remarkable durability and resistance to biodegradation contribute to their persistent presence in the environment. Microplastics within agricultural soils have prompted concerns regarding their potential impacts on agricultural practices. Functioning as significant pollutants and carriers of microcontaminants within agricultural ecosystems, microplastics and their accompanying contaminants represent ongoing challenges. Within these soil ecosystems, the fate and transportation of microplastics can detrimentally affect plant growth, microbial communities, and, subsequently, human health via the food chain. Specifically, microplastics interact with soil factors, impacting soil health and functionality. Their high adsorption capacity for hazardous microcontaminants exacerbates soil contamination, leading to increased adverse effects on organisms and human health. Due to their tiny size, microplastic debris is easily ingested by soil organisms and can transfer through the food chain, causing physiological and/or mechanical damage. Additionally, microplastics can affect plant growth and have the potential to accumulate and be transported within plants. Efforts to mitigate these impacts are crucial to safeguarding agricultural sustainability and environmental health. Future research should delve into the long-term impacts of environmental aging processes on microplastic debris within agricultural soil ecosystems from various sources, primarily focusing on food security and human beings.

Photocatalytic degradation of antibiotic sulfamethizole by visible light activated perovskite LaZnO3.

In this work, the perovskite LaZnO3 was synthesized via sol-gel method and applied for photocatalytic treatment of sulfamethizole (SMZ) antibiotics under visible light activation. SMZ was almost completely degraded (99.2% ± 0.3%) within 4 hr by photocatalyst LaZnO3 at the optimal dosage of 1.1 g/L, with a mineralization proportion of 58.7% ± 0.4%. The efficient performance of LaZnO3 can be attributed to its wide-range light absorption and the appropriate energy band edge levels, which facilitate the formation of active agents such as ·O2-, h+, and ·OH. The integration of RP-HPLC/Q-TOF-MS and DFT-based computational techniques revealed three degradation pathways of SMZ, which were initiated by the deamination reaction at the aniline ring, the breakdown of the sulfonamide moieties, and a process known as Smile-type rearrangement and SO2 intrusion. Corresponding toxicity of SMZ and the intermediates were analyzed by quantitative structure activity relationship (QSAR), indicating the effectiveness of LaZnO3-based photocatalysis in preventing secondary pollution of the intermediates to the ecosystem during the degradation process. The visible-light-activated photocatalyst LaZnO3 exhibited efficient performance in the occurrence of inorganic anions and maintained high durability across multiple recycling tests, making it a promising candidate for practical antibiotic treatment.

Using CuMgFe layered double oxide to replace laccase as a catalyst for abiotic humification.

Humification offers a promising avenue for sequestering dissolved organic carbon while facilitating environmental cleanup. In this study, CuMgFe layered double oxides (LDO) were applied as a catalyst to replace conventional enzymes, such as laccase, thereby enhancing the in vitro polyphenol-Maillard humification reaction. CuMgFe LDO was synthesized through calcination of CuMgFe layered double hydroxides (LDH) at 500 °C for 5 h. A suite of characterization methods confirmed the successful formation into mixed oxides (Cu2O, CuO, MgO, FeO, and Fe2O3) after thermal treatment. A rapid humification reaction was observed with CuMgFe LDO, occurring within a two-week span, likely due to a distinct synergy between copper and iron elements. Subsequent analyses identified that MgO in CuMgFe LDO also played a pivotal role in humification by stabilizing the pH of the reaction. In the absence of magnesium, LDO's humification activity was more pronounced in the early stages of the reaction, but it rapidly diminished as the reaction progressed. The efficiency of CuMgFe LDO was heightened at elevated temperatures (35 °C), while light conditions manifested a discernible effect, with a modest decrease in humification efficacy under indoor light exposure. CuMgFe LDO surpassed both laccase and MgFe LDH in performance, boasting a superior humification efficiency relative to its precursor, CuMgFe LDH. The catalysts' humification activity was modulated by their crystallinity and valence dynamics. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) results suggested that introducing the amino acid, glycine, expedited the CuMgFe LDO-fueled humification, enhancing the formation of C-N and C-C bonds in the resultant products. The humic-like substances derived from the catalyst-enhanced reaction displayed an elevated presence of aromatic configurations and a richer array of oxygen functional groups in comparison to a typical commercial humic material.

Advances in Hole Transport Materials for Layered Casting Solar Cells.

Huge energy consumption and running out of fossil fuels has led to the advancement of renewable sources of power, including solar, wind, and tide. Among them, solar cells have been well developed with the significant achievement of silicon solar panels, which are popularly used as windows, rooftops, public lights, etc. In order to advance the application of solar cells, a flexible type is highly required, such as layered casting solar cells (LCSCs). Organic solar cells (OSCs), perovskite solar cells (PSCs), or dye-sensitive solar cells (DSSCs) are promising LCSCs for broadening the application of solar energy to many types of surfaces. LCSCs would be cost-effective, enable large-scale production, are highly efficient, and stable. Each layer of an LCSC is important for building the complete structure of a solar cell. Within the cell structure (active material, charge carrier transport layer, electrodes), hole transport layers (HTLs) play an important role in transporting holes to the anode. Recently, diverse HTLs from inorganic, organic, and organometallic materials have emerged to have a great impact on the stability, lifetime, and performance of OSC, PSC, or DSSC devices. This review summarizes the recent advances in the development of inorganic, organic, and organometallic HTLs for solar cells. Perspectives and challenges for HTL development and improvement are also highlighted.

Novel moisturized and antimicrobial hand gel based on zinc-aminoclay and Opuntia humifusa extract.

The high antimicrobial ability and low toxicity of zinc-aminoclay (ZnAC) are claimed in our previous reports. In this study, we formulate a novel hand gel based on ZnAC and Opuntia humifusa (O. humifusa) extract, which is a high moisturizing agent. The antimicrobial activity, cytotoxicity, moisturizing effect, and clinical skin irritation of the hand gel are evaluated. The hand gel with 0.5 wt.% ZnAC and 1.0 v/v% O. humifusa extract can kill more than 99% Escherichia coli (gram-negative bacteria) and Staphylococcus aureus (gram-positive bacteria) after 24 h. Toxicity evaluation shows that, the hand gel does not affect the viability of mammalian HaCaT cells. Additionally, skin moisture is increased by applying the hand gel while its viscosity is at the standard level of commercial products. The hand gel has a skin irritation index of 0.0 and is classified as a non-irritating product. We successfully formulated hand gel from ZnAC, glucomannan, glycerol, and O. humifusa extract. Owing to the high antimicrobial activity and skin protection of hand gels, they are suitable to be used as hand sanitizers in restaurants, hospitals, and homes effectively.

Review of ZnO Binary and Ternary Composite Anodes for Lithium-Ion Batteries.

To enhance the performance of lithium-ion batteries, zinc oxide (ZnO) has generated interest as an anode candidate owing to its high theoretical capacity. However, because of its limitations such as its slow chemical reaction kinetics, intense capacity fading on potential cycling, and low rate capability, composite anodes of ZnO and other materials are manufactured. In this study, we introduce binary and ternary composites of ZnO with other metal oxides (MOs) and carbon-based materials. Most ZnO-based composite anodes exhibit a higher specific capacity, rate performance, and cycling stability than a single ZnO anode. The synergistic effects between ZnO and the other MOs or carbon-based materials can explain the superior electrochemical characteristics of these ZnO-based composites. This review also discusses some of their current limitations.

Development of Antimicrobial MgO-CuO/Activated Carbon Fiber.

Activated carbon fiber (ACF) is widely used as an adsorption fiber in air purification systems. In this study, MgO and CuO nanoparticles were immobilized on ACF with enhancement of (3-aminopropyl)triethoxysilane (APTES). The obtained fibers' coating efficiency, structural deformation, and antimicrobial activities were investigated. The MgO-CuO/APTES/ACF fiber (DA-MC) sample showed high antimicrobial activity (<90%) against both Escherichia coli and Staphylococcus aureus after 24-hour treatment. DA-MC also showed the highest coating efficiency, with no observed structural deformation. The presence of APTES and curing step at high temperature is believed to increase the coating efficiency and thus result in the high antimicrobial activity and also protect the ACF from deformation.

Development of Antimicrobial CuO/(3-aminopropyl)Triethoxysilane Activated Carbon Fiber.

CuO nanoparticles (NPs) have been used for the antimicrobial agent against different pathogenic microorganisms. In this study, CuO NPs are immobilized on the surface of activated carbon fiber (ACF) with the enhancement of (3-aminopropyl)triethoxysilane (APTES) as an organic binder. The obtained fibers are evaluated by coating efficiency, structural deformation, and antimicrobial activities. In the results, APTES can improve the immobilization of CuO on the surface of ACF. Also, the curing of silane layers at high temperature leads to the high coating efficiencies as well as structural reinforcement. The samples with drying step after APTES coating step (denoted as DA-CuO) have the highest antimicrobial activity against both Escherichia coli and Staphylococcus aureus after 24 hours treatment, respectively.

Magnesium Aminoclay (MgAC) as an Additive in Anti-Icing Mixture of Propylene Glycol Applied to Railway Electrical Wires: A Preliminary Study.

Ice accumulation on the surface of railway electrical wires can cause significant problems in the winter season. Different anti-icing liquids have been used to prevent the formation of ice on different surface substrates. The most common anti-icing liquids are ethylene glycol mixtures. Recently, propylene glycol, due to its lesser toxicity, has been considered as an alternative anti-icing agent. However, propylene glycol mixtures have some limitations, in that their degradation can lead to corrosion of the metal substrate. As detailed in the literature, (3-aminopropyl)-triethoxysilane (APTES), the precursor of magnesium aminoclay (MgAC), has been used to protect metal substrates from corrosion. In the present study we examined the potential of MgAC as an APTES-alternative additive in propylene glycol mixtures. The results showed that the anti-icing properties of the propylene glycol mixtures were maintained in the presence of MgAC (at 0.1, 0.5, and 1.0 wt.% concentrations). Furthermore, MgAC's potential as a thickening agent was shown in the increased viscosity of the propylene glycol/MgAC mixtures relative to the propylene glycol mixtures. The addition of MgAC also rendered the propylene glycol mixtures more hydrophilic. However, MgAC addition also led to corrosion due to the excess amounts of amine groups in the anti-icing solution. In this paper, the corrosion mechanism of MgAC is explained in the paper. In the future, the anti-icing and anticorrosion properties of propylene glycol/MgAC mixtures at low concentrations (<0.1 wt.%) should be more fully investigated.

A Novel Photocatalyst Composite of Magnesium Aminoclay and TiO2 Immobilized into Activated Carbon Fiber (ACF) Matrix for Pollutant Removal.

Titanium dioxide (TiO2) is a semiconductor photocatalyst widely applied in numerous fields due to possessing prominent photocatalytic properties. However, its practical applications in the form of nanoparticles or powders still have remained several limitations. Recently, novel photocatalytic porous composites have been discovered to be potential alternative approaches. In the present study, nanostructured magnesium-aminoclay-based TiO2 (MgAC-TiO2) was successfully deposited on an activated carbon fiber (ACF) matrix using the sol-gel approach followed by calcination at 350°C in an air atmosphere. The structure and photocatalytic activity of this as-prepared photocatalyst composite were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), the Brunauer-Emmett-Teller (BET), and UV-vis diffuse reflectance spectral analysis. The photocatalytic activity of MgAC-TiO2/ACF was investigated under batch conditions for the removal of methylene blue (MB) in solution under UV irradiation and dark conditions. The results revealed that MB is absorbed by MgAC-TiO2/ACF and that its photodecomposition occurs under UV irradiation. The addition of MgAC can prevent the sintering of TiO2 act as a dispersing agent to create a high specific surface area, and thus enhance photocatalytic efficiency. In addition, ACF in the MgAC-TiO2/ACF composite can additionally improve the photocatalytic activity by hindering electron-hole recombination, which is known as a synergetic effect, and thereby enhancing the photodegradation and removal efficiency of MB.

Titanium Dioxide Microscale and Macroscale Structures: A Mini-Review.

Titanium dioxide nanoparticles (TiO2 NPs) have some limitations, such as their low surface area, high bandgap energy, and low recycling ability. To overcome these limitations, TiO2 can be prepared in microscale/macroscale structures. TiO2 microscale structures, in comparison with TiO2 nanopowder, have higher surface areas, more tunable pore structures, and better top photocatalytic activity. In contrast, for TiO2 macroscale structures, although the surface area is lower than TiO2 nanopowder in many cases, they still achieve similar or better photocatalytic performance due to their unique properties. Moreover, both TiO2 microscale and macroscale structures can be easily recovered from reaction media. The difference between these two types of TiO2 structures is a function not only of size but also of the preparation process. Every type of TiO2 structure has its own advantages and disadvantages, as will be discussed further in the following pages. Future perspectives on this research field also will be discussed.

Author Correction: Synthesis of MgAC-Fe3O4/TiO2 hybrid nanocomposites via sol-gel chemistry for water treatment by photo-Fenton and photocatalytic reactions.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Synthesis of MgAC-Fe3O4/TiO2 hybrid nanocomposites via sol-gel chemistry for water treatment by photo-Fenton and photocatalytic reactions.

MgAC-Fe3O4/TiO2 hybrid nanocomposites were synthesized in different ratios of MgAC-Fe3O4 and TiO2 precursor. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray fluorescence spectrometry (XRF), electron spin resonance spectrometry (ESR), Brunauer-Emmett-Teller (BET), photoluminescence (PL), and UV photoelectron spectroscopy (UPS) were used to characterize the nanocomposites. The increase of MgAC-Fe3O4, in the hybrid nanocomposites' core-shell structure, led to the decrease of anatase TiO2 peaks, thus reducing the photo-Fenton and photocatalytic activities. According to the obtained data, MgAC-Fe3O4 [0.05 g]/TiO2 showed the best photo-Fenton and photocatalytic activities, having removed ~93% of MB (photo-Fenton reaction) and ~80% of phenol (photocatalytic reaction) after 20 and 80 mins, respectively. On the pilot scale (30 L), MgAC-Fe3O4 [0.05 g]/TiO2 was completely removed after 27 and 30 hours by the photo-Fenton and photocatalytic activities, respectively. The synergistic effect gained from the combined photo-Fenton and photocatalytic activities of Fe3O4 and TiO2, respectively, was credited for the performances of the MgAC-Fe3O4/TiO2 hybrid nanocomposites.

In-Vitro Cytotoxicity and Oxidative Stress Induced by Cerium Aminoclay and Cerium Oxide Nanoparticles in Human Skin Keratinocyte Cells.

Cerium oxide nanoparticles (CeO2 NPs) contain a number of properties suitable for biomedical, environmental and cosmetic applications, and in fact, they are well-known as inorganic sunscreen agents. Recently, cerium aminoclay (CeAC) has been considered as a hybrid material for sunscreen application, however, the basic information on the toxicity and oxidative stress induced by CeAC and CeO2 NPs on cell lines remains scanty. Therefore, the present study performed an MTT assay and ROS measurement to assess the cell viability and oxidative stress on HaCaT cells. The results showed that CeAC and CeO2 NPs exhibited low toxicities (IC50 values of 88.74/86.95 µg/mL and 84.13/83.13 µg/mL for 24 and 48 h, respectively). In particular, CeAC showed less toxicity than that did CeO2, due to its larger size, resulting in less penetration into the cell membrane, which fact reduced the level of toxicity. Notably, the coexistence of Ce3+ and Ce4+ oxidation states has been shown to promote the antioxidant activity of Ce nanomaterials, playing a major role in enhancing radical scavenging as well as reducing the intracellular ROS level on HaCaT cells. According to this estimates, CeAC and CeO2 NPs can be considered to be promising candidates for future cosmetic applications, especially sunscreens.

Surface Characterizations of Railway Electrical Wires Coated with Anti-Icing Mixtures of Ethylene Glycol or Glycerol with Tap Water.

Icing of railway contact wires in the cold climates of the USA, Canada, China, Japan, and South Korea can cause significant problems and delays in the operation schedules of electric-powered trains and subway cars. As anti-icing methods, manual de-icing, contact-wire thermal running, resistive-wire-heating de-icing, and chemical de-icing have all been explored and tested. Among them, environmentally friendly chemical de-icing based on the same concept as that of automobileengine antifreezer can be practically effective for application to contact wires at railcar depots. In the present study, the railway contact wires are coated with anti-icing mixtures of ethylene glycol/tap water and glycerol/tap water at various ratios (v/v %) as well as with tap water alone, at temperatures of -30 and -40 °C in a deep freezer. The morphological change on the wire surfaces is observed under optical microscopy. The surface-contact angles are measured to examine the surface difference between uncoated and coated railway contact-wire fragments. Conclusively, the fragments coated with 40/60 and 60/40 (v/v %) ratios of ethylene glycol or glycerol with tap water, as compared with the uncoated fragments, are shown to have been effectively de-iced. The surface-characterizations data thus indicate that mixtures of glycerol or ethylene glycol with tap water can be practical de-icing agents for application to railway contact wires.

One-Pot Synthesis of Magnesium Aminoclay-Iron Oxide Nanocomposites for Improved Photo-Fenton Catalytic Performance.

Fe3O4 nanoparticles (NPs) have been widely used in photo-Fenton catalysis applications for water/waste water treatment. Their drawbacks, however, continue to limit their potential. In the present study, we synthesized magnesium aminoclay-iron oxide [MgAC-Fe3O4] nanocomposites in DI water solution by treated them under 4% H2/Ar for 3 hours in a 500 °C furnace. Obtained X-ray diffraction (XRD) patterns confirmed that the growth of the Fe3O4 NPs in the amorphous MgAC; also, scanning electron microscopy (SEM) images indicated that the MgAC-Fe3O4 nanocomposites were in an aggregated form of 170±117 nm average-diameter. MgAC[0.7 g]-Fe3O4 nanocomposite exhibited the best photo-Fenton catalysis with methylene blue (MB) was completely removed from the treatment solution at a constant rate of 0.0083 (min-1) on the batch scale. This performance was 13.83 times better than that of commercial Fe3O4. On the pilot scale (100 L), MgAC[0.7 g]- Fe3O4 nanocomposite took 12 hours to completely removed MB from tap water. The mechanism of the high photo-Fenton catalysis was attributed to the higher rate adsorption of MgAC as well as Brunauer-Emmett-Teller (BET) surface area.

Particulate Matter Exposure of Passengers at Bus Stations: A Review.

This review clarifies particulate matter (PM) pollution, including its levels, the factors affecting its distribution, and its health effects on passengers waiting at bus stations. The usual factors affecting the characteristics and composition of PM include industrial emissions and meteorological factors (temperature, humidity, wind speed, rain volume) as well as bus-station-related factors such as fuel combustion in vehicles, wear of vehicle components, cigarette smoking, and vehicle flow. Several studies have proven that bus stops can accumulate high PM levels, thereby elevating passengers' exposure to PM while waiting at bus stations, and leading to dire health outcomes such as cardiovascular disease (CVD), respiratory effects, and diabetes. In order to accurately predict PM pollution, an artificial neural network (ANN) and adaptive neuro-fuzzy inference systems (ANFIS) have been developed. ANN is a data modeling method of proven effectiveness in solving complex problems in the fields of alignment, prediction, and classification, while the ANFIS model has several advantages including non-requirement of a mathematical model, simulation of human thinking, and simple interpretation of results compared with other predictive methods.

Effective Peroxidase-Like Activity of Co-Aminoclay [CoAC] and Its Application for Glucose Detection.

In this study, we describe a novel peroxidase-like activity of Co-aminoclay [CoAC] present at pH ~5.0 and its application to fluorescent biosensor for the determination of H2O2 and glucose. It is synthesized with aminoclays (ACs) entrapping cationic metals such as Fe, Cu, Al, Co., Ce, Ni, Mn, and Zn to find enzyme mimicking ACs by sol-gel ambient conditions. Through the screening of catalytic activities by the typical colorimetric reaction employing 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid)diammonium salt (ABTS) as a substrate with or without H2O2, Fe, Cu, and CoACs are found to exhibit peroxidase-like activity, as well as oxidase-like activity was observed from Ce and MnACs. Among them, CoAC shows exceptionally high peroxidase-like activity, presumably due to its ability to induce electron transfer between substrates and H2O2. CoAC is then used to catalyze the oxidation of Amplex® UltraRed (AUR) into a fluorescent end product, which enables a sensitive fluorescent detection of H2O2. Moreover, a highly sensitive and selective glucose biosensing strategy is developed, based on enzyme cascade reaction between glucose oxidase (GOx) and CoAC. Using this strategy, a highly linear fluorescence enhancement is verified when the concentration of glucose is increased in a wide range from 10 µM to 1 mM with a lower detection limit of 5 µM. The practical diagnostic capability of the assay system is also verified by its use to detect glucose in human blood serum. Based on these results, it is anticipated that CoAC can serve as potent peroxidase mimetics for the detection of clinically important target molecules.