Enhanced hydrogen production from food waste dark fermentation by potassium ferrate pretreatment

Improved biohydrogen production by co-fermentation of corn straw and excess sludge: Insights into biochemical process, microbial community and metabolic genes

The global climate change mainly caused by fossil fuels combustion promotes that zero-carbon hydrogen production through eco-friendly methods has attracted attention in recent years. This investigation explored the biohydrogen production by co-fermentation of corn straw (CS) and excess sludge (ES), as well as comprehensively analyzed the internal mechanism. The results showed that the optimal ratio of CS to ES was 9:1 (TS) with the biohydrogen yield of 101.8 mL/g VS, which was higher than that from the mono-fermentation of CS by 1.0-fold. The pattern of volatile fatty acids (VFAs) indicated that the acetate was the most preponderant by-product in all fermentation systems during the biohydrogen production process, and its yield was improved by adding appropriate dosage of ES. In addition, the content of soluble COD (SCOD) was reduced as increasing ES, while concentration of NH4+-N showed an opposite tendency. Microbial community analysis revealed that the microbial composition in different samples showed a significant divergence. Trichococcus was the most dominant bacterial genus in the optimal ratio of 9:1 (CS/ES) fermentation system and its abundance was as high as 41.8%. The functional genes prediction found that the dominant metabolic genes and hydrogen-producing related genes had not been significantly increased in co-fermentation system (CS/ES = 9:1) compared to that in the mono-fermentation of CS, implying that enhancement of biohydrogen production by adding ES mainly relied on balancing nutrients and adjusting microbial community in this study. Further redundancy analysis (RDA) confirmed that biohydrogen yield was closely correlated with the enrichment of Trichococcus.

Enhanced methane production from the anaerobic co-digestion of food waste plus fruit and vegetable waste

Food waste (FW) and fruit, vegetable waste (FVW) are important components of municipal solid waste, yet the performance and related mechanisms of anaerobic co-digestion of FW and FVW for methane production have been rarely investigated. In order to get a deeper understanding of the mechanisms involved, the mesophilic FW and FVW anaerobic co-digestion in different proportions was investigated. The experimental results showed that when the ratio of FW and FVW was 1/1 (in terms of volatile suspended solid), the maximum biomethane yield of 269.9 mL/g TCOD from the codigested substrate is significantly higher than that in FW or FVW anaerobic digestion alone. FW and FVW co-digestion promoted the dissolution and biotransformation of organic matter. When the recommended mixing ratio was applied, the maximum concentration of dissolved chemical oxygen demand (COD) was high as 11971 mg/L. FW and FVW co-digestion reduced the accumulation of volatile fatty acids (VFA) in the digestive system, thus reducing its negative impact on the methanogenesis process. FW and FVW co-digestion process synergistically enhanced microbial activity. The analysis of microbial population structure showed that when FW and FVW were co-digested at the recommended ratio, the relative abundance of Proteiniphilum increased to 26.5%, and the relative abundances of Methanosaeta and Candidatus Methanofastidiosum were also significantly increased. The results of this work provide a certain amount of theoretical basis and technical support for the co-digestion of FW and FVW.

Insights into organic matter evolution during food waste stabilization induced by 14-hour high-temperature fermentation

Large amounts of secondary pollutants are released during traditional composting, and rapid fermentation is desirable for the stabilization of food wastes. Food wastes were mixed with rice husk, placed in a bioreactor, and stirred continuously to achieve high-temperature fermentation for 14 h. The transformations of the mixtures were analyzed using elemental and spectral analysis combined with kinetic equations and two-dimensional correlation spectroscopy. The carbohydrates, proteins, and aliphatic compounds of food waste were degraded after 4 h of fermentation. Transformations of dissolved organic and sulfur- and nitrogen-containing substances followed first-order kinetic equations with reaction rate constants of 0.142 h^-1, 0.098 h^-1, and 0.016 h^-1, respectively. Organic matter conversion was in the following order: aliphatic → protein → carbohydrate and followed the order, acrylamide C → O-alkyl C → anomeric C at the molecular level. The fermentation process was characterized by the increase in protein- and fulvic-like compounds. Fulvic acid substances gradually accumulated during the late fermentation period. Thus, dissolved organic matter components were gradually transformed into humic substances with increasing fermentation time. The sequence of transformation during the fermentation process was, tyrosine-like → tryptophan-like → fulvic-like substances. Humification mainly occurred in the mature stage of composting; therefore, it was verified that the food waste was stabilized by a 14-h fermentation.

Calcium hypochlorite-coupled aged refuse promotes hydrogen production from sludge anaerobic fermentation

This work investigated the effect of calcium hypochlorite (CH) coupled aged refuse (AR) treatment on the enhanced hydrogen generation from sludge anaerobic dark fermentation (SADF). The enhanced mechanism was systematically revealed through sludge disintegration, organic matter biotransformation, and microbial community characteristics, etc. The experimental data showed that CH coupled AR increased the hydrogen yield to 18.1 mL/g, significantly higher than that in the AR or CH group alone. Mechanistic analysis showed that CH-coupled AR significantly promoted sludge disintegration and hydrolysis processes, providing sufficient material for hydrogen-producing bacteria. Microbiological analysis showed that CH-coupled AR increased the relative abundance of responsible hydrogen-producing microorganisms. In addition, CH-coupled AR was very effective in reducing phosphate content in the fermentation liquid and fecal coliforms in the digestate, thus facilitating the subsequent treatment of fermentation broth and digestate. CH coupled AR is an alternative strategy to increase hydrogen production from sludge.

A novel strategy and mechanism for high-quality volatile fatty acids production from primary sludge: Peroxymonosulfate pretreatment combined with alkaline fermentation

To obtain high-quality VFAs production from primary sludge, a novel strategy that combined peroxymonosulfate (PMS) pretreatment and alkaline fermentation (i.e., PMS & pH9) was proposed in the study. The results showed that PMS & pH9 was efficient in sludge solubilization and hydrolysis, resulting in a maximal VFAs yield of 401.2 mg COD/g VSS, which was 7.3-, 2.1-, and 8.8-fold higher than the sole PMS, sole pH9, and control, respectively. Acetate comprised 87.6% of VFAs in this integration system. Mechanism investigations revealed that sulfate and free radicals produced by PMS play roles in improving VFAs yield under alkaline conditions. Besides, sulfate also aided in C3∼C5 VFAs converting to acetate under alkaline conditions depending on the increase of incomplete-oxidative sulfate-reducing bacteria (iso-SRB) (i.e., Desulfobulbus and Desulfobotulus). Moreover, the relative abundances of acid-forming characteristic genera (i.e., Proteiniborus, Proteinilcasticum, and Acetoanaerobium) were higher in PMS & pH9.

Recent updates in biohydrogen production strategies and life-cycle assessment for sustainable future

Biohydrogen (bio-H₂) is regarded as a clean, non-toxic, energy carrier and has enormous potential for transforming fossil fuel-based economy. The development of a continuous high-rate H₂ production with low-cost economics following an environmentally friendly approach should be admired for technology demonstration. Thus, the current review discusses the biotechnological and thermochemical pathways for H₂ production. Thermochemical conversion involves pyrolysis and gasification routes, while biotechnological involves light-dependent processes (e.g., direct and indirect photolysis, photo/ dark fermentation strategies). Moreover, environmentally friendly technologies can be created while utilizing renewable energy sources including lignocellulosic, wastewater, sludge, microalgae, and others, which are still being developed. Lifecycle assessment (LCA) evaluates and integrates the economic, environmental, and social performance of H₂ production from biomass, microalgae, and biochar. Moreover, system boundaries evaluation, i.e., global warming potential, acidification, eutrophication, and sensitivity analysis could lead in development of sustainable bioenergy transition with high economic and environmental benefits.

Pretreatment in Vortex Layer Apparatus Boosts Dark Fermentative Hydrogen Production from Cheese Whey

Dark fermentation (DF) is a promising process for mitigating environmental pollution and producing “green” H2. However, wider implementation and scaling of this technology is hampered by insufficient process efficiency. In this work, for the first time, the effect of innovative pretreatment of cheese whey (CW) in a vortex layer apparatus (VLA) on characteristics and DF of CW was studied. Pretreatment in VLA resulted in a heating of the CW, slight increase in pH, volatile fatty acids, iron, and reduction in fat, sugar, and chemical oxygen demand (COD). The biochemical hydrogen potential test and analysis of H2 production kinetics confirmed the significant potential of using VLA in enhancement of dark fermentative H2 production. The maximum potential H2 yield (202.4 mL H2/g COD or 3.4 mol H2/mol hexose) was obtained after pretreatment in VLA for 45 s and was 45.8% higher than the control. The maximum H2 production rate after 5 and 45 s of pretreatment was 256.5 and 237.2 mL H2/g COD/d, respectively, which is 8.06 and 7.46 times higher than in the control. The lag phase was more than halved as a function of the pretreatment time. The pretreatment time positively correlated with the total final concentration of Fe2+ and Fe3+ and negatively with the lag phase, indicating a positive effect of pretreatment in VLA on the start of H2 production.

Artificial consortia of Bacillus amyloliquefaciens HM618 and Bacillus subtilis for utilizing food waste to synthetize iturin A

Food waste is a cheap and abundant organic resource that can be used as a substrate for the production of the broad-spectrum antifungal compound iturin A. To increase the efficiency of food waste biotransformation, different artificial consortia incorporating the iturin A producer Bacillus amyloliquefaciens HM618 together with engineered Bacillus subtilis WB800N producing lipase or amylase were constructed. The results showed that recombinant B. subtilis WB-A13 had the highest amylase activity of 23406.4 U/mL, and that the lipase activity of recombinant B. subtilis WB-L01 was 57.5 U/mL. When strain HM618 was co-cultured with strain WB-A14, the higher yield of iturin A reached to 7.66 mg/L, representing a 32.9% increase compared to the pure culture of strain HM618. In the three-strain consortium comprising strains HM618, WB-L02, and WB-A14 with initial OD₆₀₀ values of 0.2, 0.15, and 0.15, respectively, the yield of iturin A reached 8.12 mg/L, which was 38.6% higher than the control. Taken together, artificial consortia of B. amyloliquefaciens and recombinant B. subtilis can produce an increased yield of iturin A, which provides a new strategy for the valorization of food waste.

Alkyl polyglycosides enhanced the dark fermentation of excess sludge and plant waste to produce hydrogen: performance and mechanism

Alkyl polyglycosides (APG), a biodegradable biosurfactant, have been widely used in environmental pollution control. However, the application of APG to enhance anaerobic dark fermentation of excess sludge (ES) and plant waste (PW) to improve hydrogen production has not been reported so far. In order to fill this gap, the effect of APG on hydrogen production from ES and PW was studied in mesophilic (30 °C) environment. The results showed that APG increased the yield of hydrogen, and the recommended dose was 0.15 g/g (calculated as volatile suspended solids), accompanied by 18.7 mL/g. The contribution of APG self-degradation to hydrogen can be ignored. Mechanism investigation revealed that APG promoted the dissolution, hydrolysis, and acidification of complex organic matter, and when the content of APG was 0.15 g/g, the concentration of dissolved chemical oxygen demand (COD) was as high as 3151 mg/L; however, the dissolved concentration of COD in the blank group was only 1548 mg/L. In addition, APG improved the output of volatile fatty acids (VFA). APG promoted the proportion of acetate and butyrate in VFA, which was conducive to hydrogen production. As for the process of methanogenesis, APG reduced the consumption of hydrogen and accumulates hydrogen. This work provides an alternative strategy for the recycling of organic waste and the enhanced generation of hydrogen.

Understanding the mechanism of polybrominated diphenyl ethers reducing the anaerobic co-digestion efficiency of excess sludge and kitchen waste

Polybrominated diphenyl ethers (PBDEs) widely existing in the environment can pose a serious threat to the ecological safety. However, the influence of PBDEs on methane production by excess sludge (ES) and kitchen waste (KW) anaerobic co-digestion and its mechanism is not clear. To fill this gap, in this work, the co-digestion characteristics of ES and KW exposed to different levels of PBDEs at medium temperature were investigated in sequencing batch reactor, and the related mechanisms were also revealed. The results showed that PBDEs reduced methane production and the proportion of methane in the biogas. Methane yield decreased from 215.3 mL/g· volatile suspended solids (VSS) to 161.5 mL/(g·VSS), accompanied by the increase of PBDE content from 0 to 8.0 mg/Kg. Volatile fatty acid (VFA) yield was also inhibited by PBDEs; especially when PBDEs were 8.0 mg/Kg, VFA production was only 215.6 mg/g VSS, accounting for 75.7% of that in the control. Mechanism investigation revealed PBDEs significantly inhibited the processes of hydrolysis, acidogenesis, acetogenesis, and methanogenesis. Further study showed that PBDEs could inhibit the degradation and bioavailability of ES and KW, but it had a greater inhibition on the utilization of KW. Enzyme activity investigation revealed that all the key enzyme activities related to methane production were suppressed by PBDEs.

Surfactant rhamnolipid promotes anaerobic codigestion of excess sludge and plant waste

In order to solve the bottleneck of low methane production in anaerobic codigestion of excess sludge (ES) and plant waste (PW), a new strategy of enhancing hydrolysis and acidification by rhamnolipid (RL) was proposed under thermophilic condition. The results showed that the optimal dosage of RL was 50 g/kg total suspended solids, and the maximum yield of methane was 198.5 mL/g volatile suspended solids (VSS), which was 2.3 times of that in the control. RL promoted the dissolution of organic matter in the codigestion process of ES and PW, and the higher the dosage of RL, the higher the concentration of soluble chemical oxygen demand (SCOD) in the fermentation broth. When RL was 100 g/kg, the maximum content of SCOD in fermentation broth was 2,451 mg/L, and the contents of soluble protein and polysaccharide were 593 mg/L and 419 mg/L on 10 d, respectively, which were significantly higher than other groups. In addition, the yield of VFA in RL group was also significantly increased, and acetate and propionate were the main components of VFAs. This research work provides data support for the resource utilization of ES and PW, and expands the application field of RL.

Improvement of anaerobic co-digestion of plant waste and excess sludge using calcium peroxide

Plant waste (PW) and excess sludge (ES) are two main organic matters of municipal solid waste. However, there are few reports on their anaerobic co-digestion. In this work, the mixed proportion of PW and ES anaerobic co-digestion was first optimized at mesophilic temperature, and then the anaerobic co-digestion of PW and ES was enhanced with strong oxidant calcium peroxide (CP). The results showed that the optimal mixing ratio of PW and ES was 1/1 (in terms of volatile solids), the C/N of mixed digestion substrate was 23.5/1, and the maximum methane production was 172.6 mL/g (in terms of volatile solids). CP could enhance methane production from anaerobic co-digestion of PW and ES. When the content of CP was 0.2 g/g (in terms of total suspended solids), the maximum methane production was 234.8 mL/g, about 1.4 times of the blank. The mechanism investigation showed that CP promoted the release of organic matter during the co-digestion, and the higher the content of CP, the greater the release of soluble chemical oxygen demand. The presence of appropriate amount of CP promoted the activities of key enzymes in anaerobic fermentation process, and then increased the efficiency of methane production. The results of this work provide an alternative strategy for the resource utilization of PW and ES.

Evaluating the effect of fluoxetine on mesophilic anaerobic dark biohydrogen fermentation of excess sludge

Recently, the influence behavior of new pollutants in the environment has been widely concerned. However, the effect of antidepressants widely detected in excess sludge (ES) on biohydrogen production from anaerobic dark fermentation has never been explored. To fill this gap, fluoxetine (FLX), a typical antidepressant, was selected to evaluate its effect on ES mesophilic anaerobic dark biohydrogen fermentation. The results showed that FLX reduced biohydrogen production even at low content (0.1 mg/Kg). The biohydrogen yield was only 12.8 mL/g in the 1.8 mg/Kg (based on total suspended solids) FLX group, decreased by about 34.7%, compared with the control group (without FLX). Further mechanism investigation implied that high levels (more than 0.6 mg/Kg) of FLX reduced every step associated with the biohydrogen production. FLX reduced the concentration of ammonia nitrogen and phosphate in fermentation broth. FLX also had a significant negative effect on enzyme activity in ES dark fermentation.

Mechanisms of emerging pollutant Dechlorane Plus on the production of short-chain fatty acids from sludge anaerobic fermentation

The effect of emerging pollutant Dechlorane Plus (DPs), an organochlorine aliphatic flame retardant, on waste-activated sludge anaerobic fermentation was investigated, and the related mechanisms were revealed for the first time. The results of this experiment suggested that the presence of DPs had a significant inhibitory effect on sludge anaerobic fermentation to generate the intermediate valuable product short-chain fatty acids (SCFA), and when the DP content was 3034.1±101.7 mg/kg total suspended solids (TSS), the maximal output of SCFA was only 215.04 mg/g, which was 0.47 times of that in the blank. The underlying mechanism investigation indicated DPs promoted the disintegration of sludge, but inhibited the process of hydrolysis and acidification. DPs inhibited the release of soluble bound extracellular polymers (SB-EPS) in sludge. The analysis of microbial community characteristics indicated that DPs reduced the level of Firmicutes and Actinobacteriathe, which were the key acid producing bacteria. At the genus level, DPs reduced the relative abundance of Proteiniclasticum and Mycobacteriumwas.

Food Waste: A Promising Source of Sustainable Biohydrogen Fuel

Annually, approximately 1.3 billion tons of food is lost worldwide, accounting for one-third of annual food production. Therefore, turning food waste into energy is of enormous environmental significance because of its sustainable nature. Nutrients and organic acids present in food waste can be used to produce (bio)products such as biohydrogen through biological processes. However, our understanding of the production of biohydrogen from food waste through photofermentation and dark fermentation is still restricted. This comprehensive study aims to review the potential of food waste for biohydrogen production using microbial mediators, including a brief overview of process parameters that affect the (bio)hydrogen production pathway.

Synergetic enhancement of methane production and system resilience during anaerobic digestion of food waste in ammonia-tolerant anaerobic sludge system

The anaerobic digestion (AD) of food waste (FW) was augmented with ammonia-tolerant anaerobic sludge (ATAS). Different inoculum substrate ratios (ISR) under an initial ammonia stress of 4220 mg N/L were investigated. Results showed that the average specific methane production (SMP) of FW in the ATAS system increased by 36% compared with that in un-acclimated anaerobic sludge. SMP with ISR of 1:2.5 increased by approximately 6 times. Volatile fatty acids (VFAs) accumulation and sharp pH decline were not detected. These results revealed the high performance of ATAS in simultaneously relieving ammonia and acid stress. This improvement was attributed to multiple factors. ATAS had high ammonia tolerance and ability in conversion of acetate into methane. The equilibrium of NH₃/NH₄⁺, CO₂/H₂CO₃/HCO₃^-, and C_xH_yCOOH/C_xH_yCOO^- could promote VFAs and ammonia ionization, reduce the levels of free VFAs and ammonia, neutralize pH, and thus enhance the system's buffering capacity to be less susceptible to fluctuations. These results demonstrated that employing ATAS in improving AD performance and resilience from acid and ammonia inhibition is feasible and effective.

Effect of emerging pollutant fluoxetine on the excess sludge anaerobic digestion

Fluoxetine (FLX), an emerging pollutant, has been detected in the sewage and excess sludge (ES) at substantial levels. So far, however, the impacts of FLX on the ES anaerobic digestion and the related mechanisms have never been investigated. In this work, the effects of FLX on the ES anaerobic digestion were explored by the batch test under moderate temperature condition. The results indicated the effect of FLX on ES digestion was dose-dependent. When FLX was at a low dose (0.1 mg/kg), FLX had no significant impact on the methane generation from the ES digestion. However，when FLX was 2.0 mg/kg, the cumulative methane production was only 91.2 ± 4.3 mL/g volatile suspended solids (VSS), which was about 59.9 ± 3.4% of the blank (without FLX). Mechanisms revealed that the presence of FLX has inhibited hydrolysis, acidification and methanogenesis. Enzyme activity analysis showed that FLX inhibited the activities of key enzymes in the process of hydrolysis, acidification and methanogenesis. The results of this work are of great significance to explain the role of FLX in the process of ES fermentation, and provide some reference for the subsequent utilization of ES.

Effect of fluoxetine on enhanced biological phosphorus removal using a sequencing batch reactor

In this work, the potential impact of emerging pollutant Fluoxetine (FLX) on enhanced biological phosphorus removal (EBPR) was systematically investigated using the sequencing batch reactor. The experimental results showed that even 200 μg/L FLX had no significant effect on EBPR during the short-term exposure. However, in the long-term exposure test, high dosage of FLX inhibited EBPR. 200 μg/L FLX induced biological phosphorus removal efficiency dropped to 71.3 ± 2.1%, significantly lower than that of the blank. The mechanism investigation showed that high concentration of FLX reduced anaerobic phosphorus release and oxic phosphorus absorption, and the consumption of organic matter during the anaerobic period. In addition, FLX decreased the synthesis of intracellular polymer polyhydroxyalkanoates (PHA), but promoted the metabolism of glycogen and polyhydroxyvalerate. FLX reduced the activity of key enzymes in EBPR and the relative abundance of Accumulibacter, but improved the relative abundance of Candidatus Competibacter.

Enhancement of short-chain fatty acids production from microalgae by potassium ferrate addition: Feasibility, mechanisms and implications

Anaerobic fermentation of microalgae was always hindered by its rigid cell wall structure. This paper reports a novel technique, i.e., adding potassium ferrate (K₂FeO₄) into microalgae fermentation systems to enhance short-chain fatty acids (SCFAs) production. The results showed that the maximum SCFAs production and acetic acid proportion were 732.6 mg COD/g VS and 54.6% at a dosage of 112.8 mg Fe(VI)/g VS, which were 168% and 208% of those in the control, respectively. Mechanism studies revealed that K₂FeO₄ effectively destroyed surface morphology and cell structure, and thus facilitated microalgae solubilization, providing a large number of biodegradable substrates for subsequent SCFA production. Although K₂FeO₄ inhibited all the microbial activities relevant to hydrolysis, acidification and methanogenesis processes to some degree, its inhibition to methanogens was much severer than that to other microbes. Illumina MiSeq sequencing analyses revealed that K₂FeO₄ addition increased the relative abundance (from 9.45% to 50.4%) of hydrolytic and SCFAs-forming bacteria.

Calcium peroxide eliminates grease inhibition and promotes short-chain fatty acids production during anaerobic fermentation of food waste

Deterioration of anaerobic fermentation can occur with the presence of grease in food waste, but little information on eliminating this deterioration is currently available. In this study, it was found that the presence of 10 g/L grease decreased SCFAs production from 16.97 to 13.32 g COD/L and prolonged the optimal fermentation time to 7 days, but could be respectively recovered to 39.10 g COD/L and 4 days with 0.02 mg/g VS (volatile solids) calcium peroxide addition. Mechanism investigations indicated that calcium peroxide facilitated biodegradable organics release and improved grease degradation, thereby providing enough nutrients and better growth environments to microbes for SCFAs-producing, which could be further supported by the elevated enzymes activities responding to hydrolysis and acidification process. Further investigations revealed that among the main derivates of calcium peroxide, OH^- and Ca²⁺ played vital role in SCFAs production promotion, O₂^- and OH radicals were the main contributors to grease degradation.

Effect of initial pH on the sludge fermentation performance enhanced by aged refuse at low temperature of 10 °C

The efficiency of anaerobic fermentation of waste activated sludge (WAS) under low-temperature condition is usually low. This work reported a new strategy to enhance the low-temperature fermentation of WAS by using aged refuse (AR), and explored the effect of initial pH 4 till pH 12 on the production of short-chain fatty acid (SCFA) from AR-enhanced sludge fermentation. The results showed that AR improved WAS fermentation under low-temperature condition (10 °C), and the maximum accumulation of SCFA was 75.6 ± 3.5 mg/g, which was significantly higher than that of the blank (without AR). In addition, when the initial pH was 7, the maximum yield of methane was 102.2 ± 4.8 mL/g, whereas when the initial pH was 11, the maximum yield of SCFA was 85.6 ± 2.8 mg/g. Weak acid or alkali pH benefited hydrolysis and acidification of WAS, but inhibited methanogenesis. The release of NH4+-N and phosphate in a strong alkaline environment (pH 11 and 12) was lower than that in other alkaline environments (pH 10).

A New Zn(II) Complex: Fluorescent Detection of Fe3+ Ions in Water and Prevention Effect on DVT By Regulating Platelets Numbers and Activity of Clotting Factor

[Zn(dima)(H₂O)_0.5]·H₂O (1), a three-dimensional metal organic framework (MOF) with high porosity was formed by self-assembly of 4,6-di(1 h-imidazol-1-yl)isophthalic acid (H₂dima) and Zn²⁺ ion. Owning to its excellent luminescence and excellent water stability, complex 1 can be used as a super sensitive sensor to detect Fe³⁺ ions via the behaviors of fluorescence quenching. At the same time, the mechanism for the fluorescence quenching is also further discussed. Furthermore, the prevention effect of the compound on the deep vein thrombosis of the lower extremities (DVT) after lower venous CHIVA surgery was evaluated in vivo. Firstly, the DVT animal models was constructed and the number of platelets was measured with flow cytometry and content of clotting factor IX and anticoagulant factor III was also detected with Lowry method after compound treatment. The molecular docking simulation results indicate that the Zn(II) complex has activity to protein docking pocket with different sizes.

A Fluorescent Zn(II) Coordination Polymer: Sensitive Detection of Cr2O72- in Water and Prevention Activity On the Deep Vein Thrombosis in Orthopedic Nursing

A novel coordination polymer (CP) based on Zn(II) of [Zn(tptc)_0.5(bpy)(H₂O)]_n (1) was synthesized through utilizing the 2,2'-bipyridine (bpy) chelating N donors and p-terphenyl-2,2'',5'',5'''-tetracarboxylate acid (H₄tptc) as the co-ligands. The measurements of the fluorescence were implemented for the complex 1 in solution and solid state, and the result reveals that 1 has a strong fluorescence and it is a sensory material with great development space to determine the trace Cr₂O₇^2- (with the detection limit of 36 ppb) in the water solutions via applying the fluorescence quenching effect. As the common disease in the orthopedic nursing, the deep vein thrombosis was the objective in this research. The weigh and length of the thrombus in the animals were measured and analyzed. In addition to this, the inflammatory response in the deep vein thrombosis animal was evaluated by RT-PCR. Molecular docking results indicate that only the carboxyl group could provide polar oxygen atoms for the formed hydrogen bonds to the protein.