A new approach to explore and assess the sustainable remediation of chromium-contaminated wastewater by biochar based on 3E model.

As a cost-effective material, biochar, known as 'black gold', has been widely used for environmental applications (EA), including chromium-contaminated wastewater remediation. However, limited reports focused on the multiple impacts of biochar, including energy consumption (EC) and environmental risk (ER). Hence, to recommend biochar as a green material for sustainable development, the three critical units were explored and quantitatively assessed based on an adapted 3E model (EA-EC-ER). The tested biochar was produced by limited-oxygen pyrolysis at 400-700 °C by using three typical biomasses (Ulva prolifera, phoenix tree, and municipal sludge), and the optimal operational modulus of the 3E model was identified using six key indicators. The findings revealed a significant positive correlation between EC and biochar yield (p < 0.05). The biochar produced by phoenix tree consumed more energy due to having higher content of unstable carbon fractions. Further, high-temperature and low-temperature biochar demonstrated different chromium removal mechanisms. Notably, the biochar produced at low temperature (400 °C) achieved better EA due to having high removal capacity and stability. Regarding ER, pyrolysis temperature of 500 °C could effectively stabilize the ecological risk in all biochar and the biochar produced by Ulva prolifera depicted the greatest reduction (37-fold). However, the increase in pyrolysis temperature would lead to an increase in global warming potential by nearly 22 times. Finally, the 3E model disclosed that the biochar produced by Ulva prolifera at 500 °C with low EC, high EA, and low ER had the most positive recommendation index (+78%). Importantly, a rapid assessment methodology was established by extracting parameters from the correlation. Based on this methodology, about eight percent of biochar can be the highest recommended from more than 100 collected peer-related data. Overall, the obtained findings highlighted that the multiple impacts of biochar should be considered to efficiently advance global sustainable development goals.

Recent innovations in microplastics and nanoplastics removal by coagulation technique: Implementations, knowledge gaps and prospects.

Recently, microplastics (MPs) and nanoplastics (NPs) contamination is a worldwide problem owing to the immense usage of plastic commodities. Thus, the environmental risks by MPs and NPs demand the application of innovative, efficient, and sustainable technologies to control the pollution of plastic particles. Regarding this, numerous technologies, including adsorption, coagulation, filtration, bioremediation, chemical precipitation, and photocatalysis, have been engaged to eradicate MPs and NPs from contaminated waters. However, the coagulation technique is getting much attention owing to its simplicity, higher removal performance, low carbon footprint, and low operational and maintenance cost. Therefore, this paper has been designed to critically summarize the recent innovations on the application of coagulation process to eradicate MPs and NPs from both synthetic and real sewage. More importantly, the effect of pertinent factors, including characteristics of coagulants, MPs/NPs, and environmental medium on the elimination performances and mechanisms of MPs/NPs have been critically investigated. Further, the potential of coagulation technology in eliminating MPs and NPs from real sewage has been critically elucidated for the first time, for better execution of this technique at commercial levels. Finally, this critical review also presents current research gaps and future outlooks for the improvement of coagulation process for eradicating MPs and NPs from water and real sewage. Overall, the current review will offer valuable knowledge to scientists in selecting a suitable technique for controlling plastic pollution.

More effective application of biochar-based immobilization technology in the environment: Understanding the role of biochar.

In recent years, biochar-based immobilization technology (BIT) has been widely used to treat different environmental issues because of its cost-effectiveness and high removal performance. However, the complexity of the real environment is always ignored, which hinders the transfer of the BIT from lab-scale to commercial applications. Therefore, in this review, the analysis is performed separately on the internal side of the BIT (microbial fixation and growth) and on the external side of the BIT (function) to achieve effective BIT performance. Importantly, the internal two stages of BIT have been discussed concisely. Further, the usage of BIT in different areas is summarized precisely. Notably, the key impacts were systemically analyzed during BIT applications including environmental conditions and biochar types. Finally, the suggestions and perspectives are elucidated to solve current issues regarding BIT.

Innovations in the Development of Promising Adsorbents for the Remediation of Microplastics and Nanoplastics - A Critical Review.

Microplastics and nanoplastics are being assumed as emerging toxic pollutants owing to their unique persistent physicochemical attributes, chemical stability, and nonbiodegradable nature. Owing to their possible toxicological impacts (not only on aquatic biota but also on humans), scientific communities are developing innovative technologies to remove microplastics and nanoplastics from polluted waters. Various technologies, including adsorption, coagulation, photocatalysis, bioremediation, and filtration, have been developed and employed to eliminate microplastics and nanoplastics. Recently, adsorption technology has been getting great interest in capturing microplastics and nanoplastics and achieving excellent removal performance. Therefore, this review is designed to discuss recent innovations in developing promising adsorbents for the remediation of microplastics and nanoplastics from wastewater and natural water. The developed adsorbents have been classified into four main classes: sponge/aerogel-based, metal-based, biochar-based, and other developed adsorbents, and their performance efficiencies have been critically examined. Further, the influence of various pertinent factors, including adsorbents' characteristics, microplastics/nanoplastics' characteristics, solution pH, reaction temperature, natural organic matter, and co-existing/interfering ions on the removal performance of advanced adsorbents, have been critically assessed. Importantly, the particle application of the developed adsorbents in removing microplastics and nanoplastics from natural water has been elucidated. In addition, barriers to market penetration of the developed adsorbents are briefly discussed to help experts transfer adsorption-based technology from laboratory-scale to commercial applications. Finally, the current knowledge gaps and future recommendations are highlighted to assist scientific communal for improving adsorption-based technologies to battle against microplastics and nanoplastics pollution.

Fire releases micro- and nanoplastics: Raman imaging on burned disposable gloves.

Raman imaging can effectively characterise microplastics and nanoplastics, which is validated here to capture the items released from the plastic gloves when subjected to a mimicked fire. During the COVID-19 pandemic, large quantities of personal protective equipment (PPE) units have been used, such as the disposable gloves. If discarded and poorly managed, plastics gloves might break down to release secondary contaminants. The breakdown process can be accelerated by burning in a bushfire or at the incineration plants. During the burning process, the functional groups on the surface can be burned differently due to their different thermal stabilities. The different degrees of burning can be distinguished and visualised via Raman imaging. In the meantime, at the bottom of the burned plastics, microplastics and nanoplastics can be generated at a significant amount. The possible false Raman imaging on microplastics and nanoplastics is also discussed, by effectively extracting and distinguishing the weak signal from the background or noise. Overall, these findings confirm the importance of effectively working waste incineration plants and litter prevention, and suggest that Raman imaging is a suitable approach to characterise microplastics and nanoplastics.

Comparison of organic matter (OM) pools in water, suspended particulate matter, and sediments in eutrophic Lake Taihu, China: Implication for dissolved OM tracking, assessment, and management.

Suspended particulate matter (SPM) and sediments are important sources of dissolved organic matter (DOM) in lake water. However, studies on what extent and how both sources affect DOM composition are lacking, which hampers DOM management. Herein, DOM, SPM-extracted particulate organic matter (POM), and sediment-extracted organic matter (SOM) were characterized and compared in terms of absorption spectral properties and chemical composition in Lake Taihu, a large cyanobacterial bloom-affected shallow lake. A statistical method was proposed to quantify the similarity of organic matter (OM) in the different states and to evaluate the potential effects of SPM and sediments on DOM. Results showed that POM and DOM were mainly composed of small-molecular-size and low-humified organic components (i.e., 27 %-38 % tryptophan-like and ~30 % protein-like substances), and most of them were derived from autochthonous sources. While tyrosine-like (57 %) and humic-like (27 %) substances were dominant in SOM. The OM similarity between POM and DOM was approximately 1.5 times higher than that between SOM and DOM, indicating the greater effect of SPM than sediments on DOM composition. High pH and low nitrogen (e.g., nitrate and ammonia) were positively correlated to the OM similarity between POM and DOM. Further, the findings indicated that nitrogen limitation enhanced the OM exchange between POM and DOM by promoting the production of extracellular polymeric substances (EPS) in cyanobacterial aggregates. The obtained findings highlighted the importance of SPM in shaping the DOM composition relative to sediments and facilitating the DOM management in bloom-affected lakes.

Real-time Raman analysis of the hydrolysis of formaldehyde oligomers for enhanced collagen fixation.

Formaldehyde (FA) is widely applied as a fixative for proteins such as collagen. Current studies have confirmed that the reversible oligomer-to-monomer equilibrium of FA in aqueous solution and the proportion of FA monomer is a significant factor affecting tissue fixation. Since the hydrolysis of FA oligomers is a dynamic process affected jointly by different factors, its real time monitoring has proved to be challenging. In this work, by utilizing the well-established Raman technique as an analytical platform, we identified the factors affecting the hydrolysis of FA oligomers by rationally examining the νs (OCO) and νas (OCO) modes with varying conditions, such as time, pH, temperature, and FA concentration. The optimized conditions of the highest hydrolysis rate of oligomers into monomers for fixation on collagen and tissues have been found to be relatively low FA concentration (≤5%) in phosphate-buffered saline at pH 9.0 in room temperature. In order to compare the fixation quality of the optimized conditions to that of the conventional conditions used by current medical practices (4% FA concentration in tap water under room temperature), Raman spectroscopy and chemical derivatization methods with o-phthalaldehyde and fluorescent probe FAP-1 have been investigated, and our results revealed that the FA molecules under our optimized conditions have reacted with at least 15% more amino groups within collagen compared to those under the conventional conditions mentioned above. This study provides direct evidence of the FA equilibrium in solution by Raman spectroscopy, which could be applied for the optimal use of FA in medicine, even at an industrial scale.

An integrated approach utilizing raman spectroscopy and chemometrics for authentication and detection of adulteration of agarwood essential oils.

Agarwood is a precious aromatic plant which has good pharmacological effects such as antidepressant and sedation. It also has good ornamental and collection value. However, due to it is long and complex production process, the output of agarwood essential oils (AEOs) is scarce, so the price is expensive, the quality is uneven, and the adulteration events is endless. From the commercial and pharmaceutical point of view, the authenticity and quality of the commercial products labeled as AEOs is very important. This paper tested the applicability of Raman spectroscopy combined with chemometrics in classification and authenticity identification of AEOs. In this study, Raman spectroscopy and principal component analysis (PCA) combined with partial least square discriminant analysis (PLS-DA) were used to comprehensively evaluate AEOs from different geographical origins and/or extracted by different methods which showed different characteristic bands. The characteristic component of AEOs, chromone derivatives, and two commonly used adulterants were also detected. These characteristic bands provide spectrum information of AEO samples and reference materials, which can be used as Raman spectral markers for the qualitative identification of AEOs. This study can provide a novel, fast and convenient method for identification of AEOs.

Microfluidic Raman Sensing Using a Single Ring Negative Curvature Hollow Core Fiber.

A compact microfluidic Raman detection system based on a single-ring negative-curvature hollow-core fiber is presented. The system can be used for in-line qualitative and quantitative analysis of biochemicals. Both efficient light coupling and continuous liquid injection into the hollow-core fiber were achieved by creating a small gap between a solid-core fiber and the hollow-core fiber, which were fixed within a low-cost ceramic ferrule. A coupling efficiency of over 50% from free-space excitation laser to the hollow core fiber was obtained through a 350 µm-long solid-core fiber. For proof-of-concept demonstration of bioprocessing monitoring, a series of ethanol and glucose aqueous solutions at different concentrations were used. The limit of detection achieved for the ethanol solutions with our system was ~0.04 vol.% (0.32 g/L). Such an all-fiber microfluidic device is robust, provides Raman measurements with high repeatability and reusability, and is particularly suitable for the in-line monitoring of bioprocesses.

Fibre-Optic Surface Plasmon Resonance Biosensor for Monoclonal Antibody Titer Quantification.

An extraordinary optical transmission fibre-optic surface plasmon resonance biosensing platform was engineered to improve its portability and sensitivity, and was applied to monitor the concentrations of monoclonal antibodies (Mabs). By refining the fabricating procedure and changing the material of the flow cell and the components of the optical fibre, the biosensor is portable and robust to external interference. After the implementation of an effective template cleaning procedure and precise control during the fabrication process, a consistent sensitivity of 509 ± 5 nm per refractive index unit (nm/RIU) was achieved. The biosensor can detect the Mab with a limit of detection (LOD) of 0.44 µg/mL. The results show that the biosensor is a potential tool for the rapid quantification of Mab titers. The biosensor can be regenerated at least 10 times with 10 mM glycine (pH = 2.5), and consistent signal changes were obtained after regeneration. Moreover, the employment of a spacer arm SM(PEG)2, used for immobilising protein A onto the gold film, was demonstrated to be unable to improve the detecting sensitivity; thus, a simple procedure without the spacer arm could be used to prepare the protein A-based biosensor. Our results demonstrate that the fibre-optic surface plasmon resonance biosensor is competent for the real-time and on-line monitoring of antibody titers in the future as a process analytical technologies (PATs) tool for bioprocess developments and the manufacture of therapeutic antibodies.

Cytoplasmic delivery of quantum dots via microelectrophoresis technique.

Nanoparticles with specific properties and functions have been developed for various biomedical research applications, such as in vivo and in vitro sensors, imaging agents and delivery vehicles of therapeutics. The development of an effective delivery method of nanoparticles into the intracellular environment is challenging and success in this endeavor would be beneficial to many biological studies. Here, the well-established microelectrophoresis technique was applied for the first time to deliver nanoparticles into living cells. An optimal protocol was explored to prepare semiconductive quantum dots suspensions having high monodispersity with average hydrodynamic diameter of 13.2-35.0 nm. Micropipettes were fabricated to have inner tip diameters of approximately 200 nm that are larger than quantum dots for ejection but less than 500 nm to minimize damage to the cell membrane. We demonstrated the successful delivery of quantum dots via small electrical currents (-0.2 nA) through micropipettes into the cytoplasm of living human embryonic kidney cells (roughly 20-30 µm in length) using microelectrophoresis technique. This method is promising as a simple and general strategy for delivering a variety of nanoparticles into the cellular environment.

Compact plasmonic fiber tip for sensitive and fast humidity and human breath monitoring.

We demonstrate a plasmonic fiber tip for relative humidity (RH) detection by integrating a gold nanomembrane onto the end-face of a multimode optical fiber via a flexible and high-efficiency transfer method. Fast water condensation/evaporation is responsible for the high performance of the fiber tip in response to RH. A high sensitivity of 279 pm/%RH is obtained in the range of $ 11\% \sim 92\% {\rm RH} $11%∼92%RH. Taking advantage of the fast dynamics (response and recovery times of 156 ms and 277 ms), the plasmonic fiber tip offers an excellent detection capability to human breaths at varied frequencies and depths. The compact, easy-fabrication, and fast-dynamics plasmonic platform has versatile potential for practical applications, including environmental and healthcare monitoring, as well as biochemical sensing.

Mechanistic insight into the non-hydrolytic sol-gel process of tellurite glass films to attain a high transmission.

The development of amorphous films with a wide transmission window and high refractive index is of growing significance due to the strong demand of integrating functional nanoparticles for the next-generation hybrid optoelectronic films. High-index TeO2-based glass films made via the sol-gel process are particularly suitable as their low temperature preparation process promises high compatibility with a large variety of nanoparticles and substrates that suffer from low thermal stability. However, due to the lack of in-depth understanding of the mechanisms of the formation of undesired metallic-Te (highly absorbing species) in the films, the preparation of high-transmission TeO2-based sol-gel films has been severely hampered. Here, by gaining insight into the mechanistic chemistry of metallic-Te formation at different stages during the non-hydrolytic sol-gel process, we identify the chemical route to prevent the generation of metallic-Te in a TeO2-based film. The as-prepared TeO2-based film exhibits a high transmission that is close to the theoretical limit. This opens up a new avenue for advancing the performance of hybrid optoelectronic films via incorporating a large variety of unique nanoparticles.

Effects of nitrogen on interspecific competition between two cell-size cyanobacteria: Microcystis aeruginosa and Synechococcus sp.

Micro-cyanobacteria and pico-cyanobacteria coexist in many lakes throughout the world. Their distinct cell sizes and nutrient utilization strategies may lead to dominance of one over the other at varying nutrient levels. In this study, Microcystis aeruginosa and Synechococcus sp. were chosen as representative organisms of micro- and pico-cyanobacteria, respectively. A series of nitrate and ammonia conditions (0.02, 0.1, 0.5, and 2.5 mg N L-1) were designed in mono- or co-cultured systems, respectively. Growth rates of the two species were calculated and fitted by the Monod and Logistic equations. Furthermore, the interspecific competition was analyzed using the Lotka-Volterra model. In mono-cultures, the two cyanobacteria displayed faster growth rates in ammonia than in nitrate. Meanwhile, Synechococcus sp. showed faster growth rates compared to M. aeruginosa in lower N groups (≤ 0.5 mg N L-1). However, in the highest nitrate treatment (2.5 mg N L-1), M. aeruginosa achieved much higher biomass and faster growth rates than Synechococcus sp.. In co-cultures, Synechococcus sp. dominated in the lowest N treatment (0.02 mg N L-1), but M. aeruginosa dominated under the highest nitrate condition (2.5 mg N L-1). Based on the analysis of Raman spectra of living cells in mono-cultures, nitrate (2.5 mg N L-1) upgraded the pigmentary contents of M. aeruginosa better than ammonia (2.5 mg N L-1), but nitrogen in different forms showed little effects on the pigments of Synechococcus sp.. Findings from this study can provide valuable information to predict cyanobacterial community succession and aquatic ecosystem stability.

Incorporation of γ-butyrolactone (GBL) dramatically lowers the phase transition temperature of formamidinium-based metal halide perovskites.

We demonstrate that the δ to α phase transition temperature of formamidinium-based perovskites is reduced by ∼50 °C through the incorporation of ∼2 wt% γ-butyrolactone (GBL) into the crystal lattice. The intercalation of GBL is found to expand the unit cell of the δ-phase, reducing the energy barrier for thermal conversion.

Vortex Fluidic Mediated Synthesis of Macroporous Bovine Serum Albumin-Based Microspheres.

Macroporous bovine serum albumin (BSA) nanoparticles with controllable diameter were readily fabricated in a rapidly rotating angled glass tube in a vortex fluidic device (VFD). Systematically varying the rotational speed and the ratio of BSA, ethanol, and glutaraldehyde led to conditions for generating ca. 600 nm diameter macroporous particles that have intrinsic fluorescence emission at 520 nm when excited at 490 nm. The presence of the macropores increased the absorption efficiency of rhodamine B with potential applications for drug delivery purpose, compared with BSA nanoparticles having surfaces devoid of pores. Further control over the size of BSA nanoparticles occurred in the presence of C-phycocyanin protein during the VFD processing, along with control of their shape, from spheres to pockets, as established in exploring the parameter space of the microfluidic device.

Towards rewritable multilevel optical data storage in single nanocrystals.

Novel approaches for digital data storage are imperative, as storage capacities are drastically being outpaced by the exponential growth in data generation. Optical data storage represents the most promising alternative to traditional magnetic and solid-state data storage. In this paper, a novel and energy efficient approach to optical data storage using rare-earth ion doped inorganic insulators is demonstrated. In particular, the nanocrystalline alkaline earth halide BaFCl:Sm is shown to provide great potential for multilevel optical data storage. Proof-of-concept demonstrations reveal for the first time that these phosphors could be used for rewritable, multilevel optical data storage on the physical dimensions of a single nanocrystal. Multilevel information storage is based on the very efficient and reversible conversion of Sm3+ to Sm2+ ions upon exposure to UV-C light. The stored information is then read-out using confocal optics by employing the photoluminescence of the Sm2+ ions in the nanocrystals, with the signal strength depending on the UV-C fluence used during the write step. The latter serves as the mechanism for multilevel data storage in the individual nanocrystals, as demonstrated in this paper. This data storage platform has the potential to be extended to 2D and 3D memory for storage densities that could potentially approach petabyte/cm3 levels.

Light-controllable fiber interferometer utilizing photoexcitation dynamics in colloidal quantum dot.

The development of highly efficient light-controlled functional fiber elements has become indispensable to optical fiber communication systems. Traditional nonlinearity-based optical fiber devices suffer from the demerits of complex/expensive components, high peak power requirements, and poor efficiency. In this study, we utilize colloidal quantum dots (CQDs) to develop a light-controlled optical fiber interferometer (FI) for the all-optical control of the transmission spectrum. A specially designed exposed-core microstructure fiber (ECMF) is utilized to form the functional structure. Two types of PbS CQDs with absorption wavelengths around 1180 nm and 1580 nm, respectively, are deposited on the ECMF to enable the functional FI. The wavelength and power of control light are key factors for tailoring the FI transmission spectrum. A satisfactory recovery property and linear relationship between the spectrum shift and the power of control light at certain wavelength are achieved. The highest wavelength shift sensitivity of our light-controlled FI is 4.6 pm/mW, corresponding to an effective refractive index (RI) change of 5 × 10-6 /mW. We established a theoretical model to reveal that the RI of the CQD layer is governed by photoexcitation dynamics in CQD with the light absorption at certain wavelength. The concentration of charge carriers in the CQD layer can be relatively high under light illumination owing to their small size-related quantum confinement, which implies that low light power (mW-level in this work) can change the refractive index of the CQDs. Meanwhile, the absorption wavelength of quantum dots can be easily tuned via CQD size control to match specific operating wavelength windows. We further apply the CQD-based FI as a light-controllable fiber filter (LCFF) in a 50-km standard single-mode fiber-based communication system with 12.5-Gbps on-off keying direct modulation. Chirp management and dispersion compensation are successfully achieved by using the developed LCFF to obtain error-free transmission. CQDs possess excellent solution processability, and they can be deposited uniformly and conformally on various substrates such as fibers, silicon chips, and other complex structure surfaces, offering a powerful new degree of freedom to develop light control devices for optical communication.

Magnetically sensitive nanodiamond-doped tellurite glass fibers.

Traditional optical fibers are insensitive to magnetic fields, however many applications would benefit from fiber-based magnetometry devices. In this work, we demonstrate a magnetically sensitive optical fiber by doping nanodiamonds containing nitrogen vacancy centers into tellurite glass fibers. The fabrication process provides a robust and isolated sensing platform as the magnetic sensors are fixed in the tellurite glass matrix. Using optically detected magnetic resonance from the doped nanodiamonds, we demonstrate detection of local magnetic fields via side excitation and longitudinal collection. This is a first step towards intrinsically magneto-sensitive fiber devices with future applications in medical magneto-endoscopy and remote mineral exploration sensing.

Structures, bioactivities and future prospective of polysaccharides from Morus alba (white mulberry): A review.

Morus alba L. (family Moreaceae), also known as white mulberry, is distinguished as a source of highly promising traditional medicines (including Mori Folium, Mori Fructus, Mori Ramulus and Mori Cortex) and also functional foods. Over the past two decades, the vast majority of the studies with regard to the isolation and bioactivities of M. alba polysaccharides have mainly focused on its leaves and fruits, which are both medicinal and edible. The tender M. alba leaf is edible and can be used to make tea, the mature M. alba fruit is sweet and juicy. M. alba fruits and leaves contain rich bioactive polysaccharides, which are shown to possess various promising bioactivities, mainly including antidiabetic, immunomodulation, anti-inflammation, antioxidation, anti-obesity, hepatoprotection and renoprotection. The main purpose of this review is to provide systematically reorganized information on structural characteristics and bioactivities of M. alba polysaccharides to support their further therapeutic potentials and sanitarian functions.