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Analysis of Fluorescence and Biodegradability of Wastewater
摘要： Three-dimensional fluorescence spectrometer was adopted for the content analysis of different types of organics in coking wastewater before biochemical treatment and through biochemical treatment, and the model of parallel factors was employed to analyze fluorescence components and contents. It was found that tryptophan-like components were the most easily degraded by biology, while humic-like components were the least easily degraded. Meanwhile, it had been seen that the change trends over time of total fluorescence densities of proteinoid fluorescence, and degradable organic fluorescence were highly consistent with that of parameter values of COD, NH3-N in this wastewater after analyzing the trends of the two indexes. It was proved that the three-dimensional fluorescence spectrum method was appropriate for the accurate degradation analysis of wastewater components.
关键词： Coking wastewater,Analysis and evaluation,Biodegradation,Parallel factors model,Three-dimensional fluorescence spectrum
更新于2025-11-14 15:23:50
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Straw Degradation Behaviors under Different Conditions of Relative Air Humidity and Ultraviolet-A Irradiation
摘要： In this study, straw was degraded continuously for 150 days under one of three levels of relative air humidity (RH) (90%, 60%, or 30%) to estimate the effect of humidity on straw biodegradation. Moreover, straw was treated with ultraviolet (UV)-A irradiation + 90% RH for 180 days to evaluate the interaction between photodegradation and biodegradation. The effects of 30% and 60% RH on straw degradation was inconspicuous. Straw mass losses at 90% RH and UV-A + 90% RH were 18.5% and 39.1%, respectively. BIOLOG analysis showed that filamentous fungi played a major role in straw biodegradation. Thermogravimetric analysis showed that treatment with UV-A + 90% RH tended to increase the maximum pyrolysis rate and decreased the initial pyrolysis temperature. Compared with 90% RH, infrared spectra analysis showed that functional groups of UV-A + 90% RH treatment, e.g., –CH, –C=O, and the benzene ring structure, clearly decreased. Straw-degrading bacteria were observed by scanning electron microscopy at the beginning and end of UV-A + 90% RH treatment. Results highlight the role of humidity in the degree of straw biodegradation by filamentous fungi. Straw degradation is accelerated by the combined action of photodegradation and biodegradation under high UV-A irradiation and high humidity.
关键词： Relative air humidity,Biodegradation,TGA,Photodegradation,Ultraviolet-A irradiation,BIOLOG,SEM,ATR-FTIR
更新于2025-09-23 15:23:52
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Integrated photocatalytic-biological treatment of triazine-containing pollutants
摘要： The degradation of triazine-containing pollutants including simazine, Irgarol 1051 and Reactive Brilliant Red K-2G (K-2G) by photocatalytic treatment was investigated. The effects of titanium dioxide (TiO2) concentration, initial pH of reaction mixture, irradiation time and ultraviolet (UV) intensity on photocatalytic treatment efficiency were examined. Complete decolorization of K-2G was observed at 60 min photodegradation while only 15 min were required to completely degrade simazine and Irgarol 1051 under respective optimized conditions. High-performance liquid chromatography (HPLC), gas chromatography/mass spectrometry (GC/MS) and ion chromatography (IC) were employed to identify the photocatalytic degradation intermediates and products. Dealkylated intermediates of simazine, deisopropylatrazine and deethyldeisopropylatrazine, and Irgarol 1051 were detected by GC/MS in the initial phase of degradation. Complete mineralization could not be achieved for all triazine-containing pollutants even after prolonged (>72 h) UV irradiation due to the presence of a photocatalysis-resistant end product, cyanuric acid (CA). The toxicities of different compounds before and after photocatalytic treatment were also monitored by three bioassays. To further treat the photocatalysis-resistant end product, a CA-degrading bacterium was isolated from polluted marine sediment and further identified as Klebsiella pneumoniae by comparing the substrate utilization pattern (Biolog? microplate), fatty acid composition and 16S rRNA gene sequencing. K. pneumoniae efficiently utilized CA from 1 to 2000 mg/L as a good nitrogen source and complete mineralization of CA was observed within 24 h of incubation. This study demonstrates that the biodegradability of triazine-containing pollutants was significantly improved by the photocatalytic pre-treatment, and this proposed photocatalytic-biological integrated system can effectively treat various classes of triazine-containing pollutants.
关键词： Integration,Biodegradation,Photocatalysis,Triazine-containing pollutants
更新于2025-09-19 17:15:36
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Preparation and Photocatalytic Properties of a Bagasse Cellulose-Supported Nano-TiO2 Photocatalytic-Coupled Microbial Carrier
摘要： Intimate coupling of photocatalysis and biodegradation (ICPB) has shown promise in removing unwanted organic compounds from water. In this study, bagasse cellulose titanium dioxide composite carrier (SBC-TiO2) was prepared by low-temperature foaming methods. The optimum preparation conditions, material characterization and photocatalytic performance of the composite carrier were then explored. By conducting a single factor test, we found that bagasse cellulose with a mass fraction of 4%, a polyvinyl alcohol solution (PVA) with a mass fraction of 5% and 20 g of a pore-forming agent were optimum conditions for the composite carrier. Under these conditions, good wet density, porosity, water absorption and retention could be realized. Scanning electron microscopy (SEM) results showed that the composite carrier exhibited good biologic adhesion. X-ray spectroscopy (EDS) results confirmed the successful incorporation of nano-TiO2 dioxide into the composite carrier. When the mass concentration of methylene blue (MB) was 10 mg L?1 at 200 mL, 2 g of the composite carrier was added and the initial pH value of the reaction was maintained at 6, the catalytic effect was best under these conditions and the degradation rate reached 78.91% after 6 h. The method of preparing the composite carrier can aid in the degradation of hard-to-degrade organic compounds via ICPB. These results provide a solid platform for technical research and development in the field of wastewater treatment.
关键词： photocatalytic performance,bagasse cellulose–nano TiO2 composite carrier,characterization,intimate coupling of photocatalysis and biodegradation
更新于2025-09-19 17:13:59
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Study on Fe-xGO Composites Prepared by Selective Laser Melting: Microstructure, Hardness, Biodegradation and Cytocompatibility
摘要： The problem of the degradation rate being too slow is a key technical bottleneck to clinical applications for pure iron (Fe), a promising candidate biodegradable metal. This work used powders of pure Fe and graphene oxide (GO) to prepare Fe-xGO composites (x = 0.4 wt.%, 0.8 wt.%, 1.2 wt.%, and 1.6 wt.%) via selective laser melting (SLM), aiming to obtain a higher degradation rate. The microstructure, hardness, biodegradation and cytocompatibility were investigated. The degradation rate of the SLMed Fe-xGO composites was faster than that of SLMed Fe, due to incorporating GO into Fe. The GO content had a significant effect on the microstructure, hardness and degradation rate. The SLMed Fe-0.8 GO composite presented the finest, relatively uniform grains, had the maximum degradation rate, density and hardness, and had good cytocompatibility. The mechanisms were also clarified.
关键词： biodegradation,Fe-xGO composites,hardness,cytocompatibility,selective laser melting,microstructure
更新于2025-09-16 10:30:52
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Biodegradable and Photostable Nb2C MXene Quantum Dots as Promising Nanofluorophores for Metal Ions Sensing and Fluorescence Imaging
摘要： Conventional fluorescent probes are either easily photobleached or non-biodegradable, which often leads to the unstable fluorescence signal output and long-term biological toxicity. Therefore, the development of novel fluorescent materials with both excellent photostability and biodegradability is of great significance for further broadening their application in numerous research fields. In this work, Nb2C quantum dots (Nb2C QDs) with pristine crystallographic structures of Nb2C MXene phases and surface oxygen-containing species are synthesized by an ultrasound assisted physicochemical exfoliation in tetrapropylammonium hydroxide. Detailed analyses indicate that the Nb2C QDs not only possess excellent chemical- and photo-stable fluorescence emission but also achieve successful application in fluorescence sensing of heavy metal ions and fluorescence imaging. More importantly, it is confirmed that the Nb2C QDs present high biocompatibility and unique biodegradation property responsive to human myeloperoxidase, implying the application safety of Nb2C QDs in vivo. Under the background of ever-growing and stringent requirements for biosafety and technical stability, the biocompatibility, biodegradability, and most importantly the promising fluorescence sensing/imaging characteristic of the obtained Nb2C QDs may argue well for their future applications in environmental monitoring, biomedical diagnosis, visual display, and anti-counterfeiting.
关键词： MXene quantum dots,biodegradation,fluorescent probes,fluorescence imaging,photobleaching resistance
更新于2025-09-16 10:30:52
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The effects of drying technique and surface pre-treatment on the cytotoxicity and dissolution rate of luminescent porous silicon quantum dots in model fluids and living cells
摘要： Tailoring of the biodegradation of photoluminescent silicon quantum dots (Si QDs) is important for their future applications in diagnostics and therapy. Here, the effect of drying and surface pretreatment on the dissolution rate of Si QDs in model liquids and living cells was studied in-vitro by a combination of photoluminescence and Raman micro-spectroscopy. Porous silicon particles were obtained by mechanical milling of electrochemically etched mesoporous silicon films, and consist of interlinked silicon nanocrystals (QDs) and pores. The samples were subjected to super-critical drying with CO2 solvent (SCD) or air drying (AD) and then annealed at 600 C for 16 hours in 1% oxygen to achieve the nano-sized Si QDs. The obtained samples were characterized by a core-shell structure with a crystalline silicon core and a SiO2 layer on the surface. The sizes of the crystalline silicon core, calculated from the Raman scaterring spectra, were about 4.5 nm for initial AD-SiQDs, and about 2 nm for initial SCD-SiQDs. Both AD-Si QDs and SCD-Si QDs exhibited visible photoluminescene (PL) properties due to quantum confinement effects. The dissolution of nanocrystals was evaluated by their PL quenching , as well as by the presence of a low-frequency shift, broadening, and decrease in the intensity of the Raman signal. The stability of AD-Si QDs and the complete dissolution of SCD-Si QDs during 24 hours of incubation with cells have been demonstrated. This might explain the apparent lower cytoxicty observed for SCD-Si QDs.
关键词： air drying,silicon quantum dots,Raman micro-spectroscopy,biodegradation,photoluminescence,super-critical drying
更新于2025-09-12 10:27:22
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Studies on the Properties of Photo/Bio-Degradable Ldpe with Benzophenone and Hydrolysed Starch
摘要： Maize starch was acid hydrolyzed at 50-60?C for 6 hours. Reduced viscosity for raw starch, hydrolyzed starch (HS) and glucose were determined. DSC tests were done to determine the melting point of the modified starch. LDPE of MFI 2 g/10 min was blended with this hydrolyzed starch at various proportions of 3-20% (wt%), photo-degradable additive – benzophenone (3%) and glycerol (3%) as compatibilizer using a twin screw extruder. The formulations made using HS were easy for processing and since the MFI was increased, the starch added, proved to be hydrolyzed, Tubular blown film was extruded using blown film extruder. LDPE with hydrolysed starch are processable into thin films (< 250 microns). The films obtained were tested for various mechanical tests like tensile strength, elongation at break, etc. The mechanical properties like tensile strength and elongation at break were lowered. Tear strength and dart impact strength were lowered. Also accelerated UV weathering and compost biodegradation tests were done on all the samples. Scanning Electron Microscope images were taken before and after UV weathering and also after biodegradation to determine the morphological changes on the samples. The samples were highly photo/biodegradable and hence will not pollute the environment.
关键词： LDPE,Photo/Biodegradation,Benzophenone,Hydrolyzed starch,Mechanical properties
更新于2025-09-10 09:29:36
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Simultaneous determination of dissolved phenanthrene and its metabolites by derivative synchronous fluorescence spectrometry with double scans method in aqueous solution
摘要： A simple and sensitive derivative synchronous fluorescence spectrometry with double scans (DS-DSFS) method was developed for simultaneous determination of dissolved Phenanthrene (Phe) and its metabolites 1-hydroxy-2-naphthoic acid (1H2NA) and salicylic acid (SA) in aqueous solution. The value of 69 nm was selected as the optimal Δλ conditions for Phe and 1H2NA, and the Δλ value of 55 nm was selected for SA. The overlapping fluorescence emission spectra of Phe, 1H2NA and SA were resolved by DS-DSFS. The signals detected at wavelength of 296 nm for Phe, 352 nm for 1H2NA and 307 nm for SA vary linearly when the concentrations in the range of 4.0–1.0 × 103 μg L?1, 4.0–1.2 × 103 μg L?1 and 4.0–8.0 × 102 μg L?1, respectively. The detection limits were 0.08, 0.07 and 0.88 μg L?1 for Phe, 1H2NA and SA, with the relatively standard deviations less than 5.0%. The established method was successfully applied in the determination of Phe and the metabolites during the biodegradation of dissolved Phe in the lab. It was evidenced that the method has potential for the in situ investigation of PAH biodegradation.
关键词： Metabolites,PAHs,In situ,Derivative synchronous fluorescence spectrometry,Biodegradation
更新于2025-09-04 15:30:14
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Exploring the untapped potential of solar pretreatment for deconstruction of recalcitrant Kraft lignin in fungal biotransformation
摘要： Kraft lignin (KL) released from pulp and paper industries could cause severe environmental contamination. Appropriate effluent treatment is needed to mitigate the pollution. A novel strategy for biodegradation of KL by integrating photolysis with microbial oxidation process is reported. Results unveiled degradability of solar-treated KL (SKL) using a potential microbial strain: Trametes hirsuta MTCC-1171. Initially, KL was photodegraded by solar treatment. To analyze the chemical and physical changes in KL after solar treatment, scanning electron microscopy, Fourier transform infrared spectroscopy, and gel permeation chromatography were employed. Photolytic pretreatment induced depolymerization of chains in KL along with the cleavage of aromatic rings which made it amiable to further microbial degradation. SKL was used as a substrate to produce laccase during microbial degradation. The maximum activity of laccase of 7.1 ± 0.02 U/mL was observed on the 4th day of incubation. Microbial degradation products of photo-treated and untreated KL were identified using GC–MS. Intensification in KL degradation has been noticed along with the conversion of value-added products such as vanillin, valeric acid, and various higher alcohols. The results contribute an evidence of notable modifications of KL into value-added products using an innovative approach, which is eco-friendly and energy-efficient as well.
关键词： Kraft lignin,Yellow laccase,Biodegradation,Solar treatment,Trametes hirsuta MTCC-1171
更新于2025-09-04 15:30:14