High Removal Efficiency Research Articles

Wastewater treatment process using immobilized microalgae.

Microalgae biomass products are gaining popularity due to their diverse applications in various sectors. However, the costs associated with media ingredients and cell harvesting pose challenges to the scale-up of microalgae cultivation. This study evaluated the growth and nutrient removal efficiency (RE) of immobilized microalgae Tetradesmus obliquus in sodium alginate beads cultivated in swine manure-based wastewater compared to free cells. The main findings of this research include (i) immobilized cells outperformed free cells, showing approximately 2.3 times higher biomass production, especially at 10% effluent concentration; (ii) enhanced organic carbon removal was observed, with a significant 62% reduction in chemical oxygen demand (383.46-144.84 mg L-1) within 48 h for immobilized cells compared to 6% in free culture; (iii) both immobilized and free cells exhibited efficient removal of total nitrogen and total phosphorus, with high REs exceeding 99% for phosphorus. In addition, microscopic analysis confirmed successful cell dispersion within the alginate beads, ensuring efficient light and substrate transfer. Overall, the results highlight the potential of immobilization techniques and alternative media, such as biodigested swine manure, to enhance microalgal growth and nutrient RE, offering promising prospects for sustainable wastewater treatment processes.

Presence, behaviour, and risk assessment of volatile methylsiloxanes in wastewater: A year-long comprehensive study within a wastewater treatment plant

The awareness of possible environmental hazards caused by the widespread global use of volatile methylsiloxanes (VMSs) in personal care products (PCPs) and industrial processes has been increasing. Sewage containing these compounds may reach wastewater treatment plants (WWTPs), which are hotspots of their release into the environment. The levels, distribution, and potential risks of VMSs were studied in an unprecedently comprehensive sampling strategy (four seasonal campaigns) along the water line of a WWTP: the main influent entrance (SA1), after the preliminary treatment (SA2), after the primary treatment (SA3) and after the secondary treatment (the treated effluent; SA4). This WWTP was selected as a representative of the conventional set up based on a secondary treatment, allowing a similar approach in numerous facilities worldwide. Seven VMSs (L3, L4, L5, D3, D4, D5, D6) were analysed in wastewater samples by a small-scale liquid-liquid extraction (LLE) protocol, followed by gas chromatography–mass spectrometry (GC–MS), and the cyclic VMSs were dominant at all sampling sites and in all seasons. Considering the whole year, the total VMSs ranged from 0.4 to 22.5 μg L−1 for SA1, 0.03 to 33.7 μg L−1 for SA2, below method detection limit (MDL) to 13.2 μg L−1 for SA3 and <MDL to 0.8 μg L−1 for SA4. D5 prevailed, together with D6 and D4. The mean VMS mass flows dropped from 119 g day−1 in SA1 to 1.9 g day−1 in SA4, resulting in high removal efficiencies from the water line (>98 %). According to the risk quotients (RQ), only 18 SA4 samples (32 %) presented a minimal risk to the receiving media (0.01 ≤ RQ < 0.1). However, considering the absence of a secondary treatment or a direct discharge without treatment, there may be a risk to the environment.

Novel avenues for achieving simultaneous high-efficiency oil removal and sterilization: Designing a quaternary ammonium-hydrophobic ternary template copolymer

In treating complex sewage containing microorganisms, flocculation and disinfection typically occur as distinct stages, involving the addition of flocculants and disinfectants separately. To integrate oil removal and disinfection, a novel quaternary ammonium-hydrophobic ternary template polymer, TPAMA-DA, was engineered with capabilities for both flocculation and sterilization functions. Optimal copolymer characteristics were determined through Response Surface Methodology of the preparation parameters for TPAMA-DA. The copolymer prepared was applied to model wastewater, and the results indicate that, in emulsified oil and E. coli single systems, TPAMA-DA achieved removal rates of 95.71 % and 97.19 % for emulsified oil and OD600 (residual OD600 = 0.0239), respectively, showcasing superior oil removal and antibacterial capabilities compared to TPAMA and PAMA. Meanwhile, TPAMA-DA exhibited excellent oil removal efficiency across a broad range of pH environments, contrasting sharply with its pH-sensitive antibacterial properties. Surprisingly, applying TPAMA-DA to the oil-E. coli binary systems, it not only maintained high efficiency in oil removal but also showed certain pH adaptability in antibacterial activity, suggesting TPAMA-DA’s outstanding ability for simultaneous oil removal and antibacterial action in oil-E. coli binary systems. Impressively, SEM and 3D-EEM analyses confirm that TPAMA-DA disrupts the bacterial cell, resulting in the death of E. coli. These findings may pave the way for new avenues in the development of multi-functional, efficient, low-consumption, and environmentally friendly high-performance copolymers with dual capabilities for oil removal and sterilization.

Vermifiltration as a green solution to promote digestate reuse in agriculture in small-scale farms

Digestates from low-tech digesters need to be post-treated to ensure their safe agricultural reuse. This study evaluated, for the first time, vermifiltration as a post-treatment for the digestate from a low-tech digester implemented in a small-scale farm, treating cattle manure and cheese whey under psychrophilic conditions. Vermifiltration performance was monitored in terms of solids, organic matter, nutrients, and pathogens removal efficiency. In addition, the growth of earthworms (Eisenia foetida) and their role in the process was evaluated. Finally, the vermicompost and the effluent of the vermifilter were characterized in order to assess their potential reuse in agriculture.Vermifilters showed high removal efficiency of chemical oxygen demand (55–90%), total solids (60–80%), ammonium nitrogen (83–97%), and phosphate-P (28–49%). Earthworms effectively grew and reproduced on digestate (i.e. earthworms number increased by 183%), enhancing the vermifiltration performance, while reducing clogging and odour-related issues. Both the vermicompost and effluent produced complied with legislation limits established for soil improvers and wastewater for fertigation, respectively. Indeed, there was an absence of pathogens and non-detectable heavy metals concentrations. Vermifiltration may be thus considered a suitable post-treatment option for the digestate from low-tech digesters, allowing for its safe agricultural reuse and boosting the circular bioeconomy in small-scale farms.

In silico and experimental characterization of a new polyextremophilic subtilisin-like protease from Microbacterium metallidurans and its application as a laundry detergent additive.

Considering the current growing interest in new and improved enzymes for use in a variety of applications, the present study aimed to characterize a novel detergent-stable serine alkaline protease from the extremophilic actinobacterium Microbacterium metallidurans TL13 (MmSP) using a combined in silico and experimental approach. The MmSP showed a close phylogenetic relationship with high molecular weight S8 peptidases of Microbacterium species. Moreover, its physical and chemical parameters computed using Expasy's ProtParam tool revealed that MmSP is hydrophilic, halophilic and thermo-alkali stable. 3D structure modelling and functional prediction of TL13 serine protease resulted in the detection of five characteristic domains: [catalytic subtilase domain, fibronectin (Fn) type-III domain, peptidase inhibitor I9, protease-associated (PA) domain and bacterial Ig-like domain (group 3)], as well as the three amino acid residues [aspartate (D182), histidine (H272) and serine (S604)] in the catalytic subtilase domain. The extremophilic strain TL13 was tested for protease production using agricultural wastes/by-products as carbon substrates. Maximum enzyme activity (390U/gds) was obtained at 8th day fermentation on potato peel medium. Extracellular extract was concentrated and partially purified using ammonium sulfate precipitation methodology (1.58 folds purification fold). The optimal pH, temperature and salinity of MmSP were 9, 60°C and 1M NaCl, respectively. The MmSP protease showed broad pH stability, thermal stability, salt tolerance and detergent compatibility. In order to achieve the maximum stain removal efficacy by the TL 13 serine protease, the operation conditions were optimized using a Box-Behnken Design (BBD) with four variables, namely, time (15-75min), temperature (30-60°C), MmSP enzyme concentration (5-10U/mL) and pH (7-11). The maximum stain removal yield (95 ± 4%) obtained under the optimal enzymatic operation conditions (treatment with 7.5U/mL of MmSP during 30min at 32°C and pH9) was in good agreement with the value predicted by the regression model (98 ± %), which prove the validity of the fitted model. In conclusion, MmSP appears to be a good candidate for industrial applications, particularly in laundry detergent formulations, due to its high hydrophilicity, alkali-halo-stability, detergent compatibility and stain removal efficiency.

Investigation of cellulosic fines removal in dissolving pulp production with small-holed screen plates

This study investigates the influence of hole diameter and hole spacing on the fractionation performance using an industrial scale pressure screen. The objective is to increase the quality of the long fiber fraction during dissolving pulp production by separating cellulosic fines from unbleached softwood sulfite pulp containing 8% (w/w) primary fines (fibrous particles shorter than 0.200 mm fiber length). Different screen basket designs were applied, using the same hole spacing while varying hole diameter, and vice versa. This allowed a comparison of the separate influence of hole diameter and hole spacing on the separation efficiency. Production parameters of screening devices are always a compromise between separation efficiency, runnability/plugging, and throughput. High aperture velocity, high feed consistency and low reject rate were identified as the crucial operating parameters for high cellulosic fines removal efficiency, which turned out to be positive in terms of throughput. Considering the different hole diameters, the industrial trials showed that smaller holes yielded better fractionation results. Whereas reduced hole spacing resulted in a denser fiber network on the screen, reducing the amount of fines and short fibers passing, thereby leading to worse fractionation results. By choosing suitable screening conditions, we found that the weight-weighted fines content was reduced more than 50 percent using a one stage fiber fractionation screen set up under industrial conditions. The lowered fines content in the long fiber fraction is expected to allow a reduced purification effort and a lower chemical demand in the subsequent processes of dissolving pulp production. By reducing the fines fraction, consisting of short fibers, fiber fines, as well as mainly short-chain alkali-soluble carbohydrates (hemicelluloses), improvements in process efficiency and dissolving pulp quality can be achieved.

The impact of aeration rate on the denitrification performance and microbial community characteristics of the HN-AD bacteria-inoculated MBBR system

This study investigated the influence of aeration rates on the denitrification performance and microbial community of heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria-inoculated MBBR systems treating nitrate wastewater. The results demonstrated high removal efficiencies for COD (93.8 %) and TN (86.2 %) at an optimal aeration rate of 1 mL/min, indicating enhanced TN removal with reduced energy consumption. High-throughput sequencing results revealed that Proteobacteria, Bacteroidota, and Chloroflexi were key players in denitrification, with notable genera including Stappia, Thauera, norank_f__A4b, SM1A02, Pseudomonas, and Flavobacteria. HN-AD bacteria Stappia and Thauera played the key denitrification role at 1 mL/min and lower aeration rate was more conducive to the enrichment of Stappia and Thauera. Functional gene analysis further highlighted the importance of narG, narH and narI in denitrification processes.

High-efficiency removal of microcystis aeruginosa using Z-scheme AgBr/NH2-MIL-125(Ti) photocatalyst with superior visible-light absorption: Performance insights and mechanisms

Algal blooms have become a widespread concern for drinking water production, threatening ecosystems and human health. Photocatalysis, a promising advanced oxidation process (AOP) technology for wastewater treatment, is considered a potential measure for in situ remediation of algal blooms. However, conventional photocatalysts often suffer from limited visible-light response and rapid recombination of photogenerated electron-hole pairs. In this study, we prepared a Z-scheme AgBr/NH2-MIL-125(Ti) composite with excellent visible light absorption performance using co-precipitation to efficiently inactivate Microcystis aeruginosa. The degradation efficiency of AgBr/NH2-MIL-125(Ti) for chlorophyll a was 98.7 % after 180 min of visible light irradiation, significantly surpassing the degradation rate efficiency of AgBr and NH2-MIL-125(Ti) by factors of 3.20 and 36.75, respectively. Moreover, the removal rate was maintained at 91.1 % even after five times of repeated use. The experimental results indicated that superoxide radicals (•O2-) were the dominant reactive oxygen species involved. The photocatalytic reaction altered the morphology and surface charge of algal cells, inhibited their metabolism, and disrupted their photosynthetic and antioxidant systems. In conclusion, this study presents a promising material for the application of photocatalytic technology in algal bloom remediation.

Optimization of surface filtration to enhance wafer uniformity by removing large particle in ceria slurry

Owing to the limitations of scaling down, the development of complex structures for chip design is progressing in the semiconductor industry. As a result, the chemical mechanical polishing (CMP) process has become essential for the precise control of micro-level steps and for maintaining surface uniformity between layers during the stacking process. Structural management and improved performance of the consumables used in CMP processes are required. In particular, controlling the abrasive particles in the slurry that directly contact the wafer surface is crucial. Large particles within the slurry can occur scratches and cause non-uniformity in the polishing process, thus the particle size distribution of the slurry must be regulated. In this study, two types of filtration systems were constructed to determine the optimal conditions for CMP of ceria slurry. Depth filtration effectively removes particles through a cake layer formation mechanism but has limitations in achieving a consistent pore size within the fiber layer. Consequently, separation efficiency for particle sizes is relatively low. In contrast, surface filtration consisting of a single membrane demonstrates a consistent correlation between pore size and the size of the filtered particles, resulting in high particle removal efficiency. The pore size capable of removing large particles without active particle loss was 200 nm. After evaluating slurry productivity and filter-induced agglomeration, 0.8 L per minute (LPM) was identified as the optimal flow rate. Additionally, after filtration at 0.8 LPM, the maximum reduction in removal rates was relatively small at 272.54 Å/min due to decreased edge removal rates. However, by removing large particles to implement a monodisperse state, an improvement in uniformity of 17.11 % was achieved. Therefore, the CMP performance can be enhanced using surface filtration to control the particle size distribution (PSD).

The development of Giant reed biochar for adsorption of Basic Blue 41 and Eriochrome Black T. azo dyes from wastewater

The textile industry is discharging high concentrations of anionic and cationic azo dyes into the nearby environment, which can cause adverse effects on public health, and the aquatic environment. Therefore, this study aimed to develop giant reed biochar and apply for the removal of Basic blue 41 (BB41) and Eriochrome black T (EBT) azo dyes from water. Characterization techniques such as BET surface area analyzer, Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermal gravimetric analyzer (TGA) were applied for biochar description. The biochar exhibits a high fixed carbon content (80.4%), a low ash content (3.8%), a large surface area (429.0 m2/g), and good thermal stability. High removal efficiencies of BB41 98.6% and EBT 82.5% were recorded at the specific experimental condition. The experimental data were fitted with the Langmuir isotherm model at R2 0.99 for both dyes whereas the adsorption kinetics revealed the pseudo-second-order kinetics at R2∼\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim$$\\end{document} 1 and 0.99 for BB41 and EBT, respectively. Furthermore, four regenerations of biochar with adsorption performances of BB41 and EBT dyes were found to be 94.7% and 79.1%, respectively. Finally, this adsorbent can be considered an economically viable material for the removal of synthetic dyes from wastewater systems. In conclusion, the study findings showed that the adsorbent material is promising to apply for water and wastewater treatment but still, the study of adsorption interaction and modifications of the surface functionalities are essential to accommodate multipollutant removal from real water systems.

Insights into Adsorption Behavior and Mechanism of Br- onto Nickel-Aluminum Layered Double Hydroxides Intercalated with Different Inorganic Anions.

Layered double hydroxides (LDHs) have garnered significant attention from researchers in the field of adsorption due to their unique laminated structures and ion exchange properties. LDHs with various anion intercalation showed different adsorption effects on adsorbing ions, but the corresponding adsorption mechanisms are ambiguous. In this study, three types of NiAl-LDHs were synthesized, utilizing NO3-, CO32-, or Cl- as the interlayer anions. Batch tests were conducted to study their adsorption performances for Br-. Among them, the LDH with a NO3- intercalation layer exhibited the highest adsorption capacity for Br-, reaching up to 1.40 mmol g-1. The adsorption kinetics, mechanism, and renewability of these NiAl-LDHs were systematically compared. As a result, the type of Br- adsorption by all three materials was single molecular layer chemisorption. Moreover, the thermodynamic results of adsorption suggested that the adsorption of Br- was a spontaneous exothermic process. X-ray photoelectron spectroscopy, X-ray diffraction, and point of zero charge analysis collectively indicated that the adsorption of Br- by LDHs primarily occurred through interlayer ion exchange and electrostatic interactions. Structural characterizations of the adsorbents revealed that Br- entered the interlayers of the three LDHs, causing varying degrees of reduction in the interlayer spacing. Density functional theory calculations indicated that the interlayer binding energy of LDH with NO3- intercalation was the lowest, thereby making it more susceptible NO3- to be exchanged with Br-. Finally, the stability of the NiAl-LDHs was studied. The NiAl-LDHs retains a high removal efficiency of Br- even after 5 cycles of adsorption and desorption.

Utilizing Mixed Cultures of Microalgae to Up-Cycle and Remove Nutrients from Dairy Wastewater.

This study explores the novel use of mixed cultures of microalgae-Spirulina platensis, Micractinium, and Chlorella-for nutrient removal from dairy wastewater (DW). Microalgae were isolated from a local wastewater treatment plant and cultivated under various light conditions. The results showed significant biomass production, with mixed cultures achieving the highest biomass (2.51 g/L), followed by Spirulina (1.98 g/L) and Chlorella (1.92 g/L). Supplementing DW (75%) with BG medium (25%) significantly enhanced biomass and pH levels, improving pathogenic bacteria removal. Spirulina and mixed cultures exhibited high nitrogen removal efficiencies of 92.56% and 93.34%, respectively, while Chlorella achieved 86.85% nitrogen and 83.45% phosphorus removal. Although growth rates were lower under phosphorus-limited conditions, the microalgae adapted well to real DW, which is essential for effective algal harvesting. Phosphorus removal efficiencies ranged from 69.56% to 86.67%, with mixed cultures achieving the highest removal. Microbial and coliform removal efficiencies reached 97.81%, with elevated pH levels contributing to significant reductions in fecal E. coli and coliform levels. These findings suggest that integrating microalgae cultivation into DW treatment systems can significantly enhance nutrient and pathogen removal, providing a sustainable solution for wastewater management.

Treatment of Textile Wastewater from Spinning Mill Using Electrocoagulation-Flocculation Process

Textile spinning mills generate wastewater containing high levels of pollutants such as suspended solids, dyes, oils, and organic compounds. This study investigates the electrocoagulation-flocculation (ECF) process as a sustainable treatment method. ECF combines electrocoagulation, where an electric current induces pollutant coagulation, and flocculation, which aggregates these pollutants for removal. Extensive lab experiments were conducted, analyzing setup, procedures, and results. The study found that ECF significantly reduced pollutants, achieving high removal efficiencies for suspended solids, COD, color, and oil/grease. Economic analysis confirmed ECF's cost- effectiveness over conventional methods. A case study demonstrated successful implementation, highlighting operational efficiency and environmental compliance. The paper concludes with recommendations for future research and industrial applications. Key Words: Electrocoagulation, Textile Wastewater, Sustainable Wastewater Treatment, Spinning Mill, Pollutant Removal

Efficient removal of polycyclic aromatic hydrocarbons from aqueous solutions using green cyclodextrin-maltodextrin nanosponge incorporated polyvinyl alcohol cryogel

Developing efficient adsorbents for removing polycyclic aromatic hydrocarbons (PAHs) from aqueous solutions is a significant and worthwhile approach. In this study, we showcase a method for fabricating β-cyclodextrin-maltodextrin nanosponges (βCD-MD) incorporated polyvinyl alcohol (PVA) cryogel for removing PAHs from aqueous solutions. The composite nanosponges enhanced the adsorption efficiency of PAHs such as Naphthalene, Acenaphthene, Fluorene, Phenanthrene, Anthracene, Fluoranthene, Pyrene, and Benzo[a]pyrene from water samples and the porous PVA cryogel helped to entrap and prevent the loss of the adsorbent. This efficacy was attributed to the strong affinities of PAHs toward βCD-MD nanosponges, facilitated by hydrophobic interactions between the analytes and the hydrophobic inner region present in both dextrins. The removal efficiency of the prepared βCD-MD/PVA composite cryogel was more than 95 % for all 8 PAHs (C0 = 5.0 mg/L) in less than 30 min, and the experimental data were well described by the Freundlich isotherm and the pseudo-second-order kinetic model. Additionally, the βCD-MD/PVA composite cryogel exhibited a maximum adsorption capacity ranging from 16.34 to 18.49 mg/g for eight PAHs. Moreover, the thermodynamic study revealed that the adsorption of PAHs was an endothermic and spontaneous process. The βCD-MD/PVA composite cryogel exhibited an abundance of polar functional groups along with numerous hydrophobic cavities and regions. It demonstrated high mechanical and thermal stability and maintained high removal efficiency even after seven adsorption–desorption cycles. Overall, it was concluded that βCD-MD/PVA composite cryogel can be utilized as a high-performance, eco-friendly, and sustainable alternative for PAH removal.

Bacillus subtilis as an effective tool for bioremediation of lead, copper and cadmium in water

Bioremediation is a promising technique for the removal and recovery of contaminated areas, which is based on the ability of organisms to convert toxic substances into less harmful or inert compounds. Here, we evaluate the capacity of the Bacillus subtilis (BS) bacteria to bioadsorved heavy metals such as lead (Pb), copper (Cu) and cadmium (Cd) in water samples. Water samples were laboratory contaminated Pb at 500 ppm, Cu and Cd at 100 ppm. First, the growth curve of BS was plotted using Tryptone Soy Broth (TSB) at 100% (TSB100) and 33% (TSB33). Later, BS was studied in water containing all three metals separately and simultaneously. All solutions were stirred at 150 rpm, 35 ℃ for periods that ranged from 1 to 144 h. The heavy metal analyses were performed by X-ray fluorescence and Inductively Coupled Plasma Mass Spectrometry. The results showed that BS was resistant to Cu, Cd and Pb in water, with active multiplication and reduction in the concentration of the metals. The highest removal efficiency, in the presence of each heavy metal, reached 100% with Pb, 92.3% with Cd and 89% with Cu. In the solution with the mixture of heavy metals, Cd and Pb levels reduced significantly. However, the mixture of metals negatively affected the removal of Cu. In conclusion, the implement using Bacillus-type bacteria can be efficient in the biosorption of heavy metals from aqueous solutions and can be employed as a cost-effective treatment for the bioremediation of industrial effluents and contaminated areas.

Tourmaline triggered biofilm transformation: Boosting ultrafiltration efficiency and fouling resistance

Ultralow pressure filtration system, which integrates the dual functionalities of biofilm degradation and membrane filtration, has gained significant attention in water treatment due to its superior contaminant removal efficiency. However, it is a challenge to mitigate membrane biofouling while maintaining the high activity of biofilm. This study presents a novel ceramic-based ultrafiltration membrane functionalized with tourmaline nanoparticles to address this challenge. The incorporation of tourmaline nanoparticles enables the release of nutrient elements and the generation of an electric field, which enhances the biofilm activity on the membrane surface and simultaneously alleviates intrapore biofouling. The tourmaline-modified ceramic membrane (TCM) demonstrated a significant antifouling effect, with a substantial increase in water flux by 60 %. Additionally, the TCM achieved high removal efficiencies for contaminants (48.78 % in TOC, 22.28 % in UV254, and 24.42 % in TN) after 30 days of continuous operation. The fouling resistance by various constituents in natural water was individually analyzed using model compounds. The TCM with improved electronegativity and hydrophilicity exhibited superior resistance to irreversible fouling through increased electrostatic repulsion and reduced adhesion to foulants. Comprehensive characterizations and analyses, including interfacial interaction energies, redox reaction processes, and biofilm evolutions, demonstrated that the TCM can release nutrient elements to facilitate the development of functional microbial community within the biofilm, and generate reactive oxygen species (ROS) on the membrane surface to the degrade contaminants and mitigate membrane biofouling. The electric field generated by tourmaline nanoparticles can promote electron transfer in the Fe(III)/Fe(II) cycle, ensuring a stable and sustainable generation of ROS and bactericidal negative ions. These synergistic functions enhance contaminant removal and reduce irreversible fouling of the TCM. This study provides fundamental insights into the role of tourmaline-modified surfaces in enhancing membrane filtration performance and fouling resistance, inspiring the development of high-performance, anti-fouling membranes.

A handy way for forming N-doped TiO2/carbon from pectin and d,l-serine hydrazide hydrochloride

N-doped TiO2/carbon composites (N-TiPC) have shown excellent photodegradation performances to the organic contaminants but are limited by the multistage preparation (i.e., preparation of porous carbon, preparation of N-doped TiO2, and loading of N-doped TiO2 on porous carbon). Here, we develop a handy way by combining the Pickering emulsion-gel template route and chelation reaction of polysaccharides. The N-TiPC is obtained by calcinating pectin/Dl-serine hydrazide hydrochloride (SHH)-Ti4+ chelate and is further described by modern characterization techniques. The results show that the N atom is successfully doped into the TiO2 lattice, and the bandgap value of N-TiPC is reduced to 2.3 eV. Moreover, the particle size of N-TiPC remains about 10 nm. The configurations of the composites are simulated using DFT calculation. The photocatalytic experiments show that N-TiPC has a high removal efficiency for methylene blue (MB) and oxytetracycline hydrochloride (OTC-HCL). The removal ratios of MB (20 mg/L, 50 mL) and OTC-HCL (30 mg/L, 50 mL) are 99.41 % and 78.29 %, respectively. The cyclic experiments show that the photocatalyst has good stability. Overall, this study provides a handy way to form N-TiPC with enhanced photodegradation performances. It can also be promoted to other macromolecules such as cellulose and its derivatives, sodium alginate, chitosan, lignin, etc.

Using Zeolite Materials to Remove Pharmaceuticals from Water.

Pharmaceutical drugs, including antibiotics and hormonal agents, pose a significant threat to environmental and public health due to their persistent presence in aquatic environments. Colistin (KOL), fluoxetine (FLUO), amoxicillin (AMO), and 17-alpha-ethinylestradiol (EST) are pharmaceuticals (PhCs) that frequently exceed regulatory limits in water and wastewater. Current removal methods are mainly ineffective, necessitating the development of more efficient techniques. This study investigates the use of synthetic zeolite (NaP1_FA) and zeolite-carbon composites (NaP1_C), both derived from fly ash (FA), for the removal of KOL, FLUO, AMO, and EST from aquatic environments. Batch adsorption experiments assessed the effects of contact time, adsorbent dosage, initial concentration, and pH on the removal efficiency of the pharmaceuticals. The results demonstrated that NaP1_FA and NaP1_C exhibited high removal efficiencies for all tested pharmaceuticals, achieving over 90% removal within 2 min of contact time. The Behnajady-Modirshahla-Ghanbary (BMG) kinetic model best described the adsorption processes. The most effective sorption was observed with a sorbent dose of 1-2 g L-1. Regarding removal efficiency, the substances ranked in this order: EST was the highest, followed by AMO, KOL, and FLUO. Sorption efficiency was influenced by the initial pH of the solutions, with optimal performance observed at pH 2-2.5 for KOL and FLUO. The zeolite-carbon composite NaP1_C, due to its hydrophobic nature, showed superior sorption efficiency for hydrophobic pharmaceuticals like FLUO and EST. The spectral analysis reveals that the primary mechanism for immobilizing the tested PhCs on zeolite sorbents is mainly due to physical sorption. This study underscores the potential of utilizing inexpensive, fly ash-derived zeolites and zeolite-carbon composites to remove pharmaceuticals from water effectively. These findings contribute to developing advanced materials for decentralized wastewater treatment systems, directly addressing pollution sources in various facilities.

Construction of a multifunctional paper-based fluorescent material for the detection and adsorption of formaldehyde

Indoor air pollution is one of the significant inducing factors of some diseases, such as leukemia, tumors, respiratory disease, and kidney failure. Among these contaminants, formaldehyde has a long release span and is a great threat to our health. However, methods for formaldehyde elimination and detection are limited. Herein, a new paper-based multifunctional fluorescent material was developed for the simultaneous high-efficiency removal and detection of formaldehyde. The paper-based material was fabricated using polyethyleneimine (PEI) and a highly sensitive ratiometric fluorescent probe (FP). The paper-based material can detect formaldehyde with a significant change in fluorescence: the fluorescence at 450 nm decreased by over 75 %, and the fluorescence of FP in the ratiometric channel increased by over 100-fold. Moreover, the formaldehyde elimination rate is up to 99 %. By combining the porous network structures of paper, the abundant amino groups in PEI, and the highly sensitive fluorescent response of FP, the multifunctional fluorescent paper material can be effectively utilized for formaldehyde removal and detection.

Inorganic carbon metabolism enhanced hydrogen-driven denitrification: Evaluation of carbon fixation pathways and microbial traits

H2-driven denitrification offers a promising alternative for treating low C/N wastewater amidst global nitrogen pollution, due to its advantages of high removal efficiency, low energy consumption, and independence from exogenous organic carbon source. While inorganic carbon assimilation is crucial for the growth and reproduction of autotrophic microorganisms, it remains uncertain whether the fixation of inorganic carbon could impact H2-driven denitrification. This work demonstrated that the supplement of inorganic carbon efficiently improved the efficiency of nitrate removal to 90.3%, compared to 78.0% in the control. Further analysis indicated that inorganic carbon supplementation shifted the microbial structure from autotrophic-dominated (e.g., Hydrogenophaga and Rhodococcus with abundance of 2.3% and 2.6%) to mixotrophic-dominated (e.g., Thauera and Microscillaceae sp. with abundance of 5.6% and 32.8%). Additionally, although H2 boosted the carbon fixation via the reductive TCA cycle and Wood-Ljungdahl pathway, the Calvin-Benson cycle emerged as the predominant pathway, significantly boosted under inorganic carbon supplementation, along with the upregulation of critical enzyme expression including RuBisCo (EC 4.1.1.39), PGK (EC 2.7.2.3) and GAPDH (EC 1.2.1.12). Moreover, the expressions and activities of functional enzymes involved in nitrogen transformation, including nitrate reductase (NAR), nitrite reductase (NIR) and nitric oxide reductase (NOR), as well as microbial electron transfer ability, were remarkably enhanced under sufficient inorganic carbon conditions. This work contributed to understanding the carbon metabolism mechanism in H2-driven denitrification, thereby facilitating the promotion of the efficient and low-carbon approach for nitrogen removal from wastewater.