Ion Exchange Research Articles

A novel efficient electrochemical sensor for detecting paracetamol contaminants in polluted water using an active electrode from tungsten oxide nanoplates.

Herein, electrochemical sensing of paracetamol in polluted water was achieved using facile-synthesized tungsten oxide nanoparticles. Ion exchange resin has been used as a sustainable preparation route, while the prepared nanoparticles have been characterized by XRD and SEM analyses. Orthorhombic WO3·H2O nano-plates have been synthesized via a facile preparation method, where the crystal size has been calculated as 25-33 nm, and these results were used to create a 3D model of the prepared WO3·H2O nano-plates. An active electrochemical sensor layer of the prepared WO3·H2O has been used to detect paracetamol in water with a concentration range of 0-50 mg L-1. The tungsten oxide nanoplates show high sensitivity with a detection-limit of 66 μM and sensitivity of 12.85 μA μM-1. Kinetic models have been investigated, where pseudo 1st and 2nd order models were used to study the sensing mechanism. Both experimental results and mathematical calculations have been combined and used to provide suggested sensing mechanisms. The current investigations may be the key factor of future, economic and eco-friendly environmental sensors for industrial wastewater treatment.

How Do the Valency and Radii of Cations Affect the Rheological Properties of Aqueous Solutions of Zwitterionic and Anionic Surfactant Mixtures?

Despite extensive research on the use of salts to enhance micellar growth, numerous questions remain regarding the impact of ionic exchange and molecular structure on charge neutralization. This study looks into how certain cations (Na+, Ca2+, and Mg2+) affect the structure of a cocamidopropyl betaine CAPB and sodium dodecylbenzenesulfonate SDBS surfactant mixture, aiming toward applications in targeted delivery systems. The mixture consists of a zwitterionic surfactant, cocamidopropyl betaine (CAPB), and an anionic surfactant, sodium dodecylbenzenesulfonate (SDBS), combined in varying molar ratios at a total concentration of 200 mM. We characterized the macroscale properties through rheological measurements and obtained detailed structural insights using small-angle X-ray scattering (SAXS) and cryogenic electron microscopy (cryo-EM). The findings reveal that increasing the concentration of cations in the CAPB/SDBS mixture induces the formation of peaks in the zero-shear viscosity as a function of salt concentration (salt curve). Analysis through cryo-EM and SAXS showed that these viscosity peaks are related to the change of micellar assemblies from entangled worm-like micelles to branched worm-like micelles and then to bilayer structures (vesicles). The specific cation concentration at which the zero-shear viscosity peak occurs, as well as the maximum viscosity, is strongly influenced by the type of cation present in the CAPB/SDBS solutions, a phenomenon explained by the Hofmeister series. Notably, the differing affinities of cations for the carboxylate COO- and sulfite SO3- groups and the partial dehydration of micelles contribute to the lower concentration of magnesium cations required to reach the viscosity peak compared to calcium cations.

Hydrogeochemical characterization of shallow and deep groundwater for drinking and irrigation water quality index of Kathmandu Valley, Nepal.

A comprehensive hydrogeochemical analysis of 156 groundwater samples (106 shallow and 50 deep) was conducted in the Kathmandu Valley, Nepal. This study addresses a significant research gap by focusing on the hydro-geochemical composition and contamination of groundwater in the Kathmandu Valley, an area with limited detailed assessments. The novelty of this work lies in its comprehensive analysis of both shallow and deep groundwater, particularly concerning the high concentration of contaminants like arsenic, microbial pathogens, and ammonium, which are critical for public health. The results indicate that the mean concentration of turbidity, iron (Fe), and total coliform (TC) was exceeded the permissible range by National Drinking Water Quality Standards (NDWQS). Hydro-geochemical analysis using the Piper and Chadha diagrams showed the Ca2⁺-Mg2⁺-HCO₃ dominance, suggesting carbonate rock weathering and ion exchange as primary processes. Gibbs and mixing diagrams further supported these findings. The Water Quality Index ranged from 3.93 to 442.11 (mean: 66.87) for shallow water while 8.07 to 252.87 (mean: 79.24) with turbidity, iron, and ammonia significantly contributing to the overall index. Salinity hazard assessment considering total dissolved solids, sodium adsorption ratio, sodium percentage, magnesium adsorption ratio, and Kelly ratios, indicated that shallow and deep groundwater samples are suitable for irrigation, as confirmed by Wilcox diagrams. This study provides valuable insights into the groundwater quality of Kathmandu Valley and highlights the need for effective management strategies to ensure sustainable use of this vital resource, providing a nuanced understanding of groundwater quality and its implications for water management in the region. The findings can inform water treatment practices, policy-making, and future research, ultimately aiding in the development of safer and more sustainable groundwater management practices for the region.

Unconventional and Powerful Ion Sources for Solid-State Ion Exchange, Cu2SO4 and Cu3PO4: Exemplified by the Synthesis of Metastable β-CuGaO2 from Stable β-LiGaO2.

This study introduces a new method for synthesizing Cu+-containing metastable phases through ion exchange. Traditionally, CuCl has been used as a Cu+ ion source for solid-state ion exchanges; however, its thermodynamic driving force is often insufficient for complete ion exchange with Li+-containing precursors. First-principles calculations have identified Cu2SO4 and Cu3PO4 as more powerful alternatives, providing a higher driving force than CuCl. It has been experimentally demonstrated that these ion sources can open up new reaction pathways through experimental ion exchanges, such as from β-LiGaO2 to β-CuGaO2, which were previously unattainable. An important perspective provided by this study is that the potential of such simple compounds to act as powerful ion sources has been overlooked and that they were identified through straightforward first-principles calculations. This work presents the initial strategic design of an ion-exchange reaction by exploring suitable ion sources, thereby expanding the potential for synthesizing metastable materials.

Synthesis and Application of LTA Zeolite for the Removal of Inorganic and Organic Hazardous Substances from Water: A Review

Industrialization and human activities have caused significant environmental challenges, with water pollution posing severe risks to human health. This underscores the urgent need for effective water treatment solutions. Zeolites, known for their high specific surface area and stability, have gained increasing attention as adsorbents for water treatment. Among zeolites, LTA varieties stand out due to their low Si/Al ratio, which enhances ion-exchange capacity, and their cost-effectiveness. This review focuses on the synthesis of low-silica LTA zeolites, particularly zeolite A, using natural materials and solid wastes without relying on organic-structure-directing agents (OSDAs). Common pretreatment processes for such synthesis are also highlighted. The review further explores the applications of LTA zeolites in water treatment, emphasizing their exceptional performance in adsorbing inorganic and organic pollutants. In particular, LTA zeolites are highly effective at removing inorganic cation pollutants through ion exchange. An updated ion-exchange selectivity order, based on previous studies, is provided to support these findings. Overall, this review aims to guide future research and development in water treatment technologies.

Mitigating cadmium contamination in soil using Biochar, sulfur-modified Biochar, and other organic amendments

Biochar is a novel approach to remediating heavy metal-contaminated soil. Using various organic amendments like phyllosilicate-minerals (PSM), compost, biochar (BC) and sulfur-modified biochar (SMB), demonstrates superior adsorption capacity and stability compared to unmodified biochar (BC). The adsorption mechanisms of SMB are identified for its potential to increase soil-pH and reduce available cadmium (Cd). The study reveals the potential of BC and SMB in immobilizing Cd in contaminated soil. SMB demonstrated the highest adsorption capacity for Cd, followed by BC, PSM, and compost, with capacities ranging from 7.47 to 17.67 mg g−1. Both BC and SMB exhibit high adsorption capacities (12.82 and 17.67 mg g−1, respectively) and low desorption percentages (4.46–6.23%) at ion strengths of 0.01 to 0.1 mol-L−1 and pH levels ranging from 5 to 7. SMB showed a higher adsorption capacity (17.67 mg g−1) and lower desorption percentage (4.46–6.23%) compared to BC. The adsorption mechanism involves surface-precipitation, ion exchange, and the formation of Cd(OH)2 and CdCO3 precipitates, as well as interactions between Cd and organic sulfur, leading to more stable-Cd and CdHS+ compounds. Adding 1% SMB increased soil pH and significantly reduced available Cd, demonstrating its potential for pollutant remediation. The study underscores the promise of SMB in providing a sustainable solution for Cd-contaminated soil remediation.

A novel carbonyl reductase for the synthesis of (R)-tolvaptan

Screening carbonyl reductases with the ability to catalyze the reduction of complex carbonyl compounds is of great significance for the biosynthesis of R-tolvaptan(R-TVP). In this study, the target carbonyl reductase in the crude enzyme extract of rabbit liver was separated, purified, and identified by ammonium sulfate precipitation, gel-filtration chromatography, ion exchange chromatography, affinity chromatography, and protein mass spectrometry. With the rabbit liver genome as the template, the gene encoding the carbonyl reductase rlsr5 was amplified by PCR and the recombinant strain was successfully constructed. After RLSR5 was purified by affinity chromatography, its enzymatic properties were characterized. The results indicated that the gene sequence of rlsr5 was 972 bp, encoding a protein with a molecular weight of 40 kDa. RLSR5 was a dimeric protein, and each monomer was composed of a (α/β)8-barrel structure. RLSR5 could asymmetrically reduce 7-chloro-1-[2-methyl-4-[(2- methylbenzoyl)amino]benzoyl]-5-oxo-2,3,4,5-tetrahydro-1H-1-benzazepine (prochiral ketone, PK) to synthesize R-TVP. The specific activity of the enzyme was 36.64 U/mg, and the optical purity of the product was 99%. This enzyme showcased the optimal performance at pH 6.0 and 30 °C. It was independent of metal ions, with the activity enhanced by Mn2+. This study lays a foundation for the biosynthesis of tolvaptan of optical grade.

Comparative Study of the Sensory Impacts of Acidifiers for Red Wine Production

Rising temperatures have caused a major shift in wine chemistry, including increased sugar and pH along with decreased acidity. Wines produced from such grapes tend to be microbiologically unstable and are often described as unpalatable. This study looks at treatments to lower pH and enhance sensory characteristics of wines produced from grapes grown at higher temperatures. The four acidification treatments included the following: tartaric acid; verjus—an acidic juice made from unripe grapes; glucose oxidase with catalase enzyme (GOx), which converts glucose to gluconic acid; and ion exchange. All treatments were able to reduce pH to the target pH of 3.6. Sensory analysis was conducted using the Hierarchical Rate-All-That-Apply (HRATA) method and preference testing. Analysis of the HRATA and GCMS data using Principal Component Analysis (PCA) accounted for 78.69% and 70% of the variance observed, respectively. Wines treated with GOx and verjus exhibited the most distinct sensory profiles when compared to each other, the other treatments, and the control group. GOx-treated wines were associated with positive flavor descriptors including caramel, hazelnut, lemon, and fruity which correlated well with the aromatic compounds determined by GCMS. There were no significant differences in consumer preferences of treatments. This study shows how different acidifiers can be utilized by winemakers to affect not just the pH and acidity but also the aromatic and flavor profile of the wine.

Injectable Biocompatible Zeolite Nanocrystals for Enhanced Tumor Oxygenation and MRI Imaging.

Tumor hypoxia significantly limits the effectiveness of radiotherapy, as oxygen is crucial for producing cancer-killing reactive oxygen species. To address this, we synthesized nanosized faujasite (PBS-Na-FAU) zeolite crystals using clinical-grade phosphate-buffered saline (PBS) as the solvent, ensuring preserved crystallinity, microporous volume, and colloidal stability. The zeolite nanocrystals showed enhanced safety profiles in vitro and ex vivo, and in vivo studies showed no apparent toxicity to animals. They demonstrated a high oxygen capacity with a release rate of 2.68 mg/L under hypoxic conditions. The introduction of gadolinium (Gd3+) into the zeolite nanocrystals by ion exchange, replacing three monovalent cations (Na+ and K+), led to an increased oxygen capacity of the sample. In situ Fourier transform infrared (FTIR) study revealed that Gd-containing zeolite (PBS-Gd-FAU) adsorbed ∼23% more oxygen at 20 kPa compared to the as-synthesized sample (PBS-Na-FAU). In vivo magnetic resonance imaging (MRI) demonstrated targeted oxygen delivery and release within brain tumors, revealing 14.91 and 17.10% differences in cerebral blood volume (CBV) between tumor and contralateral brain tissue after 15 and 20 min, respectively, compared to the control. T1 maps at 7 T indicated a relaxation rate of 9.254 mM-1·s-1 for PBS-Gd-FAU, twice that of commercial Gd-chelates. These findings highlight the potential of Gd-containing zeolite nanocrystals synthesized in PBS as a biocompatible platform for enhancing tumor oxygenation in anticancer therapy, with significant clinical translation potential.

Bone Diagenesis and Extremes of Preservation in Forensic Science

Understanding the composition and diagenetic processes of the deposition environment is pivotal to understanding why bone undergoes preservation or diagenesis. This research explores the complex nexus of diagenesis at the extremes of preservation, via the interdependent chemical, and short- and long-term microbial processes that influence diagenesis. These processes include dissolution, ion exchange, hydrolysis, recrystallisation, waterlogging, acidity and alkalinity, soil composition, redox potential, bacterial activity, and microbiome composition. Diagenetic processes are discussed in relation to typical sites and sites with extremes of preservation. Understanding site conditions that impact diagenetic processes is critical to understanding the visual features presented in recovered skeletal material, ensuring an appropriate post-mortem interval is assigned, and for subsequent post hoc analysis of bone.

Preparation of Highly Stable Wood with Fast Curing, Ultraviolet, and Mildew Resistance through Copper-Montmorillonite Nanoparticles Hybridized with Tung Oil.

Wood has a number of undesirable inherent properties that limit its ability to be used in a wider range of applications. For this reason, in this study, copper-montmorillonite nanoparticles were prepared from natural biomass tung oil and the natural mineral montmorillonite by the ion exchange method. Modified wood with tung oil intercalated with copper-montmorillonite was prepared by a simple and environmentally friendly impregnation and natural curing process. The natural curing rate of tung oil was greatly accelerated by the addition of copper-montmorillonite nanoparticles. The surface contact angle of the wood increased from 85.0° to 152.2° after copper-montmorillonite-tung oil treatment, and remarkably, it remained at 144.2° after 180 s. After 192 h of immersion, the water absorption decreased by 90.0% compared with the control group, of which the resistance to swelling was as high as 59.00%, which significantly improved the dimensional stability of the wood. After 15 days of ultraviolet irradiation, the copper-montmorillonite-tung oil-treated wood showed a 68.89% reduction in redness value compared to the control and a significant increase in ultraviolet resistance. Copper-montmorillonite-tung oil-treated wood showed greatly enhanced effectiveness against mildew. On the eighth day of Aspergillus niger infestation, the control wood was already full of mildew, whereas the copper-montmorillonite-tung oil-treated wood was not infested with mildew. In particular, after 28 days of infestation by Penicillium oryzae, the modified wood remained free of the fungus, with 100% mildew prevention efficiency. In addition, after 2 weeks of leaching, the leaching rate of the impregnated material was only 0.22%, facilitating long-term protection of the wood. The present study by the copper-montmorillonite synergistic tung oil treatment strategy provides innovative methods and potential ideas for extending the service life of wood products and high-value utilization of wood and also has the potential to scale up wood protection.

Porous covalent organic framework liquid for boosting CO2 adsorption and catalysis via dynamically expanding effect

Abstract The features of intrinsic porosity and fluidity endow porous liquids (PLs) unique properties and performances but the preparation of PLs remains challenging due to the difficulty in liquefying and keeping porous features at the same time. Herein, we develop a stepwise surface functionalization and ion exchange strategy to achieve a rare example of flexible covalent organic framework (COF) based porous liquid (COF-PLs). By coating the outer surface of the judiciously selected three-dimensional flexible COF-301 with an imidazolium salt corona, followed by liquefaction using the anion canopy potassium poly(ethylene glycol) sulfonate (PEGS) via electrostatic interactions to obtain the flexible porous liquid COF-301-PL. Theoretical calculations and CO2 adsorption experiments reveal that the cavities of COF-301-PL undergo dynamic adjustments in response to changes in CO2 pressure. The dynamic expansion effect not only can provide additional gas adsorption capacity (7.04 mmol/g at 40 bar) but also facilitate the mass transfer of gas molecules during the catalytic process. Consequently, COF-301-PL exhibits superior catalytic efficiency for the conversion of CO2 into cyclic carbonate by a factor of 24 and 17 compared to those of PEGS and COF-301 solid counterpart, respectively. The optimization of substrate adsorption and mass transfer conditions consequently improves the overall efficiency of catalytic reactions. This work offers a new perspective on the preparation of PLs and their large potential application for gas adsorption and catalysis.

Improved interfacial li-ion transport in composite polymer electrolytes via surface modification of LLZO

Composite polymer electrolytes that incorporate ceramic fillers in a polymer matrix offer mechanical strength and flexibility as solid electrolytes for lithium metal batteries. However, fast Li+ transport between polymer and Li+-conductive filler phases is not a simple achievement due to high barriers for Li+ exchange across the interphase. This study demonstrates how modification of Li7La3Zr2O12 (LLZO) nanofiller surfaces with silane chemistries influences Li+ transport at local and global electrolyte scales. Anhydrous reactions covalently link amine-functionalized silanes [(3-aminopropyl)triethoxysilane (APTES)] to LLZO nanoparticles, which protects LLZO in air. APTES functionalization lowers the poly (ethylene oxide) (PEO)-LLZO interphase resistance to half that of unmodified LLZO and increases effective Li+ transference number, while insulating Al2O3 completely blocks ion exchange and lowers transference number and conductivity in PEO-lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)-LLZO composites. Modeling an inner resistive interphase between LLZO and PEO surrounded by an outer conductive interphase explains non-linear conductivity trends. Solid-state 7Li & 6Li nuclear magnetic resonance shows Li+ only exchanges between PEO-LiTFSI and some LLZO interphase, with no appreciable Li+ transport through bulk LLZO. Surface functionalization is a promising path toward lowering the polymer-ceramic interphase resistance. This work demonstrates that local changes in Li+ transport affect macroscopic performance, highlighting the intricate relationships between all interfaces in inherently heterogeneous composite polymer electrolytes.

In silico optimization of a challenging bispecific antibody chromatography step.

Mechanistic modeling of chromatographic steps is an effective tool in biopharma process development that enhances process understanding and accelerates optimization efforts and subsequent risk assessment. A relatively new model for ion exchange chromatography is the colloidal particle adsorption (CPA) formalism, which promises improved separation of material and molecule-specific parameters. This case study demonstrates a straightforward CPA modeling workflow to describe an ion exchange chromatography polishing step of a knobs-into-holes construct bispecific antibody molecule. An adapted Yamamoto method was used to calculate charge and equilibrium parameters at three pH values. The remaining model parameters, binding kinetics, and effective mass transfer coefficients were determined via inverse fitting. The model was created from six experiments in total, tested on model parameter uncertainty, and evaluated on its power to predict changes in the biomolecule's retention behavior when variations in elution salt concentration occur. Finally, a three-step-gradient experiment was optimized, separating the desired bispecific antibody from its low and high molecular weight impurities, achieving a monomer yield of 68% and purity of 96%. Testing the model against a different load composition demonstrated its ability to extrapolate. An in silico one-factor-at-time and two-parameter screening of the optimized method identified the salt concentration to elute weaker binding impurities as a critical process attribute, while deviations in the buffer pH had a minor influence.

Microbe-assisted phytoremediation for sustainable management of heavy metal in wastewater - A green approach to escalate the remediation of heavy metals.

Water pollution from Heavy metal (HM) contamination poses a critical threat to environmental sustainability and public health. Industrial activities have increased the presence of HMs in wastewater, necessitating effective remediation strategies. Conventional methods like chemical precipitation, ion exchange, adsorption, and membrane filtration are widely used but possess various limitations. These include high costs, environmental impacts, and the potential for generating secondary pollutants, highlighting the need for sustainable alternatives. Phytoremediation, enhanced by microbial interactions, offers an eco-friendly solution to this issue. The unique physiological and biochemical traits of plants, combined with microbial metabolic capabilities, enable efficient uptake and detoxification of HMs. Microbial enzymes play a crucial role in these processes by breaking down complex compounds, enhancing HM bioavailability, and facilitating their conversion into less toxic forms. Synergistic interactions between root-associated microbes and plants further improves metal absorption and stabilization, boosting phytoremediation efficiency. However, challenges remain, including the limited bioavailability of contaminants and plant resilience in highly polluted environments. Recent advancements focus on improving microbial-assisted phytoremediation through mechanisms like bioavailability facilitation, phytoextraction, and phytostabilization. Genetic engineering facilitates the altering of genes that control plant immune responses and growth which improves the ability of plants to interact beneficially with microbes to thrive in HM rich environments while efficiently cleaning contaminated wastewater. This review examines these strategies and highlights future research directions to enhance wastewater remediation using phytoremediation technologies.

Advancements in functional adsorbents for sustainable recovery of rare earth elements from wastewater: A comprehensive review of performance, mechanisms, and applications.

Rare earth elements (REEs) are crucial metallic resources that play an essential role in national economies and industrial production. The reclaimation of REEs from wastewater stands as a significant supplementary strategy to bolster the REEs supply. Adsorption techniques are widely recognized as environmentally friendly and sustainable methods for the separation of REEs from wastewater. Despite the growing interest in adsorption-based REEs separation, comprehensive reviews of both traditional and novel adsorbents toward REEs recovery remain limited. This review aims to provide a thorough analysis of various adsorbents for the recovery of REEs. The types of adsorbents examined include activated carbons, functionalized silica nanoparticles, and microbial synthetic adsorbents, with a detailed evaluation of their adsorption capacities, selectivity, and regeneration potential. This study focuses on the mechanisms of REEs adsorption, including electrostatic interactions, ion exchange, surface complexation, and surface precipitation, highlighting how surface modifications can enhance REEs recovery efficiency. Future efforts in designing high-performance adsorbents should prioritize the optimization of the density of functional groups to enhance both selectivity and adsorption capacity, while also maintaining a balance between overall capacity, cost, and reusability. The incorporation of covalently bonded functional groups onto mechanically robust adsorbents can significantly strengthen chemical interactions with REEs and improve the structural stability of the adsorbents during reuse. Additionally, the development of materials with high specific surface areas and well-defined porous structures is benifitial to facilitating mass transfer of REEs and maximizing adsorption efficiency. Ultimately, the advancement of the design of efficient, highly selective and recyclable adsorbents is critical for addressing the growing demand for REEs across diverse industrial applications.

A Study of Halide Ion Exchange-Induced Phase Transition in CsPbBr3 Perovskite Quantum Dots for Detecting Chlorinated Volatile Compounds.

The unique optical properties of perovskite quantum dots (PQDs), particularly the tunable photoluminescence (PL) across the visible spectrum, make them a promising tool for chlorinated detection. However, the correlation between the fluorescence emission shift behavior and the interface of phase transformation in PQDs has not been thoroughly explored. In this study, we synthesized CsPbBr3 PQDs via the hot-injection method and demonstrated their ability to detect chlorinated volatile compounds such as HCl and NaOCl through a halide exchange process between the PQDs' solid thin film and the chlorinated vapor phase. This exchange process, which occurs alongside chloride (Cl) and bromine (Br) ion exchange and halide atom rearrangement, leads to sequential structural changes: the initial CsPbBr3 cubic Pm3̅m phase transitions to the CsPb2BrxCl5-x tetragonal I4/mcm phase, which subsequently transforms into the CsPbBrxCl3-x orthorhombic Pnma phase. The detailed exploration of this proposed mechanism during chlorinated vapor detection with CsPbBr3 PQDs thin films, supported by X-ray diffraction (XRD) analysis and PL spectrum over time, revealed high sensitivity to HCl vapor. The limit of detection (LOD) for HCl vapor was determined to be 0.02 ppm in visual recognition and 0.005 ppm via PL spectra. Additionally, the LOD for NaOCl was established at 0.50 ppm, facilitated by the photolysis reaction accelerating the conversion of NaOCl to HCl vapor under UV light irradiation. These insights have enriched our understanding of the mechanisms involved and broadened the potential use of CsPbBr3 PQDs as PL detection probes for chloride ions.

An efficient and industrially feasible process for purification and immobilization of orange‐peel‐based lipase for biocatalytic applications

AbstractLipase is an important enzyme with wide industrial applications in various sectors. The present study focuses on the development of an efficient and industrially feasible process for the purification and immobilization of orange‐peel‐based lipase. The integration of ultrafiltration (UF), adsorptive chromatography, and immobilization on synthetic resins offers an efficient method for producing purified, immobilized lipases. Ultrafiltration membranes with varying molecular weight cutoffs were evaluated for concentrating crude lipase. Among the membranes tested, the 5 kDa UF membrane demonstrated over 94% enzyme activity retention. Various microporous adsorbents (hydrophilic, hydrophobic and ion exchange) were tested for removing color impurities from concentrated crude lipase. The hydrophobic adsorbent achieved over 90% removal of color components. Overall, the integration of UF membranes and adsorptive chromatography showed a 2.29‐fold increase in production efficiency. Different microporous adsorbents were tested for the immobilization of purified lipase to produce an immobilized lipase biocatalyst. The use of hydrophobic adsorbents with lower porosity and a larger surface provides maximum binding efficiency (95%). The characterization study of purified lipase was conducted by using Fourier transform infrared (FTIR) spectroscopy and sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE). The purification process yielded a lipase enzyme concentration of 0.28 mg mL−1 with a specific activity of 250.54 U mL−1, achieving an approximately 2.29‐fold increase in purity. This study presents an efficient and industrially viable method for the purification and immobilization of lipases, enabling their use in biocatalytic applications.

Microbial community structure and water quality performance in local scrubber reclaim system for water reclamation of the semiconductor industry: A case study of a semiconductor plant in Beijing.

The local scrubber reclaim (LSR) system plays a critical role in water reclamation and in reducing environmental pollution emissions in semiconductor factories. This study monitored the changes in water quality and assessed the key stages of pollutant removal, with a primary focus on evaluating microbial growth and the shifts in microbial community structure and function in the LSR system. The results showed that activated carbon filtration (ACF) effectively removed total organic carbon (TOC) with a removal rate of 59.35%, while ion exchange (IEX) was essential for reducing conductivity, with a removal rate of 87.33%. Furthermore, severe bacterial growth was observed (more than 1000CFU/ml) in the system. Bacteria numbers in the MMF and ACF stages grew dramatically, at least four times higher than that in the influent tank. After chlorination in the storage tank, microbial numbers sharply dropped, yet microbial diversity increased. The dominant microbial group in the LSR system was Patescibacteria (average relative abundance was 32.37%), considered part of the "microbial dark matter" and also known as Candidate Phyla Radiation (CPR). Following the effluent from the storage tank, the biofilm-forming potential of bacteria significantly increased (relative abundance rose from 7.19% to 15.20%), along with a varying increase in the abundance of genes related to metabolism. Measures should be implemented to prevent pipeline blockage and improve water reclamation efficiency.

Advances in waste-derived functional materials for PFAS remediation.

Per- and polyfluoroalkyl substances (PFAS) are synthetic organofluoride compounds, widely used in industries since the 1950s for their hydrophobic properties. PFAS contamination of soil and water poses significant environmental and public health risks due to their persistence, chemical stability, and resistance to degradation. The Chemical Abstracts Service catalogs approximately 4300 PFAS globally. Research in various regions such as North America, Asia, Europe, and remote polar zones has revealed the accumulation of perfluorooctane sulfonate (PFOS) in the tissues of various animal species, with concentrations reaching up to 1900ng/g in aquatic species like dolphins and whales. Researchers have employed various remediation techniques such as solvent extraction, ion exchange, precipitation, adsorption, and membrane filtration, each of which has its drawbacks. Adsorption, particularly using waste-derived functional materials like biochar, is emerging as a promising method for PFAS remediation due to its cost-effectiveness and sustainability. For example, waste timber-derived biochar exhibits adsorption efficiency comparable to commercial activated carbon. This review highlights advancements in using agricultural, industrial, and biological waste-derived materials for sustainable PFAS remediation. We discuss innovative modification techniques like hydrothermal synthesis, pyrolysis, calcination, co-precipitation, the sol-gel method, and ball milling. The study also examines adsorption mechanisms, factors affecting adsorption efficiency, and the technological challenges in scaling up waste-derived material use. It aims to explore developments, challenges, and future directions for using these materials for efficient PFAS remediation and contributing to sustainable environmental cleanup solutions.