Elaborate Design of Two Novel Fluorescent Zinc-based Metal-Organic Frameworks for Highly Efficient Tetracycline Antibiotics Detection

The abuse of tetracycline antibiotics has caused great harm to human health and ecosystems.Developing inexpensive,convenient and sensitive methods for the detection of tetracycline antibiotics is highly desirable.Herein,based on the H_(4)ddp ligand[H_(4)ddp=3-(3,5-dicarboxyphenyl)pyridine-2,6-dicarboxylic acid],two novel zinc-based metal-organic frameworks(MOFs){[Zn_(3)(ddp)_(2)(H_(2)O)_(4)]·3H_(2)O}n(Zn1-ddp)and{[Zn_(3)(ddp)_(2)(H_(2)O)_(4)]·3H_(2)O}n(Zn2-ddp)were successfully designed by delicate structural regulation.Both Zn1-ddp and Zn2-ddp exhibited excellent water and chemical stability and showed excellent fluorescence quenching performance for tetracycline antibiotics.Notably,the more advanced framework structure and better fluorescent performance make Zn1-ddp more sensitive than Zn2-ddp in fluorescent detection with a detection limit of 0.29µmol/L for tetracycline(TC),0.09µmol/L for doxycycline(DOX),0.10µmol/L for minocycline(MIN)and metacycline(MEL),0.19µmol/L for chlortetracycline(CTC),and 0.67µmol/L for oxytetracycline(OTC)among tetracycline antibiotics.The fluorescence quenching mechanism of Zn1-ddp and Zn2-ddp for tetracycline antibiotics detection was deeply investigated.The reasons for the superior detection performance of Zn1-ddp over Zn2-ddp were also analyzed in depth through Fourier transform infrared spectrophotometry(FTIR),X-ray photoelectron spectroscopy(XPS)analysis and framework structure analysis.The developed method opens up a new perspective for antibiotics detection based on zinc-based MOFs.

Applying an AIE type fluorescent probe in the detection of tetracycline antibiotics

The typical representative TPB(tetraphenyl-1,3-butadiene)molecule with AIE effect was used as a fluorescent probe,and the specific recognition of tetracycline antibiotics was achieved through the comparison of the experimental results of the quenching of TPB by nine antibiotics of different types,which indicated that tetracycline antibiotics were found to quench TPB to the greatest extent,while the quenching of other antibiotics(e.q.chloramphenicol,aminoglycoside,sulfonamides,and quinolone)was not obvious.Then the quantitative relationship between the concentration of antibiotic solution and the effect of fluorescence quench was investigated by taking oxytetracycline among tetracycline antibiotics as an example,and the detection limit was calculated.Finally,it was found that the UV absorption spectra of tetracycline hydrochloride and the fluorescence excitation spectra of TPB had high overlap,while the overlap between the UV absorption spectra of other antibiotics,such as sulfadimethoxine,and the fluorescence laser spectrum of TPB was low,which fulfilled the fluorescence internal filtering effect.The fluorescence probe has stable properties,low cost and strong anti-interference ability,which makes the method more valuable in the practical detection of tetracycline.This study indicates great potent in the detection of antibiotics.

Selective adsorption of tetracycline by β-CD-immobilized sodium alginate aerogel coupled with ultrafiltration for reclaimed water

In this work,a novel composite material based on β-cyclodextrin-immobilized sodium alginate aerogel(β-CD/NaAlg) was developed utilizing cross-linker of epichlorohydrin and applied as an adsorbent to remove tetracycline antibiotics from reclaimed wastewater.A series of characterizations were utilized to confirm the successful synthesis of the adsorbent and this β-CD/NaAlg presented a three-dimensional network at the nanoscale or microscale.Under optimal conditions(pH=4,t=8 h,β-CD:NaAlg=9,adsorbent dosage = 1.5 g·L-1),the maximum removal rate of β-CD/NaAlg to tetracycline was 70%.The adsorption behavior of tetracycline on β-CD/NaAlg conformed to the Freundlich isotherm model(R2=0.9977) and the pseudo-second-order kinetic model(R^(2)=0.9993).Moreover,the adsorbent still removed 55.3% of tetracycline after five cycles.Specially,the adsorbent was integrated with ultrafiltration to adsorb tetracycline antibiotics from simulated reclaimed wastewater,and the removal rate of tetracycline reached 78.9% within 2 h.The existence of Cr(Ⅵ) had a negligible impact on tetracycline removal,while the presence of humic acid exhibited a promoting effect.The possible adsorption mechanisms were also elucidated through X-ray photoelectron spectroscopy and density functional theory analysis.In summary,β-CD/NaAlg represents an environmentally friendly,efficient,and sustainable adsorbent for removing tetracycline antibiotics from reclaimed water.

Phosphine production in anaerobic wastewater treatment under tetracycline antibiotic pressure

The influence of tetracycline（TC） antibiotics on phosphine（PH3） production in the anaerobic wastewater treatment was studied. A lab-scale anaerobic baffled reactor with three compartments was employed to simulate this process. The reactor was operated in a TC-absence wastewater and 250 μg/L TC-presence wastewater for three months after a start-up period,respectively. The responses of p H, oxidation–reduction potential（ORP）, chemical oxygen demand（COD）, total phosphorus（TP）, enzymes activity（dehydrogenase and acid phosphatase）,and microbial community were investigated to reveal the effect of TC on PH3 production.Results suggested that the dehydrogenase（DH） activity, acid phosphatase（ACP） activity and COD have positive relationship with PH3 production, while p H, ORP level and the TP in liquid phase have negative relationship with PH3 production. With prolonged TC exposure, decrease in p H and increase in DH activity are beneficial to PH3 production, while decrease in COD and ACP activity are not the limiting factors for PH3 production.

Preparation of hydrophilic molecularly imprinted polymers for tetracycline antibiotics recognition

Hydrophilic molecularly imprinted polymers（MIPs） were prepared using tetracycline as template,methacrylic acid as monomer and glycidilmethacrylate as pro-hydrophilic co-monomer.Compared with common MIPs,the imprinting effect and adsorption amounts of hydrophilic MIPs for tetracycline（TC） were greatly improved in water media.Furthermore,the electrochemical sensor fabricated by modifying hydrophilic MIPs on glassy carbon electrode was developed for the determination of TC in foodstuff samples.

A new Eu-MOF for ratiometrically fluorescent detection toward quinolone antibiotics and selective detection toward tetracycline antibiotics

Development of new self-calibrating fluorescent sensing methods has been a popular research field with the aim of protecting the human health and environment sustainability. In this work, a novel Eu-based metal organic framework(MOF) Eu(2,6-NDC)(COO)(BUC-88) was developed by employing 2,6-NDC(2,6-naphthalenedicarboxylic acid) as bridging ligands. BUC-88 performed different sensing process toward quinolone antibiotics and tetracyclines antibiotics in terms of fluorescence intensity and color. BUC-88exhibited excellent selectivity and sensitivity detection property toward enrofloxacin(ENR), norfloxacin(NOR) and ciprofloxacin(CIP) over other Pharmaceutical and Personal Care Products(PPCPs), accomplishing the detection limit of 0.12 μmol/L, 0.52 μmol/L, 0.75 μmol/L, respectively. Notably, BUC-88 acted as an excellent fluorescence sensor for tetracyclines antibiotics with fast response time(less than 1 s), high selectivity and sensitivity(LODs = 0.08 μmol/L). The fluorescent detection method was successfully used for visual and ultrasensitive detection of ENR, NOR, CIP and tetracycline hydrochloride(TC) in lake water with satisfied recovery from 99.75% to 102.30%. Finally, the photoinduced electron transfer and the competitive absorption of ultraviolet light are the main mechanisms for sensitive detection toward quinolone antibiotics and tetracyclines antibiotics.

Preparation of high selective molecularly imprinted polymers for tetracycline by precipitation polymerization

High selective molecularly imprinted polymers （MIPs） for tetracycline have been prepared by precipitation polymerization. Effects of monomer and solvent, the ratio of monomer and template and the characterization of the polymer were investigated by frontal chromatography and selectivity experiment. The results clearly indicated that the polymer, which had the highest molecular recognition abilities for tetracycline antibiotics, had been received.

Effects of anaerobic composting on tetracycline degradation in swine manure

Oxytetracycline(OTC) and tetracycline(TC) are the most common TC antibiotics used in human and veterinary medicine.Residual amounts of these antibiotics in manure pose a potential threat to public and ecological health as a result of the potential for them to be released to the environment following land application of manure from animals treated with antibiotics.We investigated the degradation of OTC and TC during anaerobic composting.We tested the effects of temperature and antibiotic concentration on degradation rates in a control and in manure spiked with TCs.We examined changes in p H,biological degradation material(BDM),and moisture corresponding with antibiotic degradation of TCs in the swine manure.Results showed that the OTC and TC concentrations decreased by between 68.54% and 95.50% in all nine treatments following 14 days of anaerobic composting,and the highest removal ef ficiencies were observed at an incubation temperature of 55°C and initial concentrations of 10.36 μg·g^(-1),and 5.96 μg·g^(-1) of OTC and TC,respectively,which were degraded by 95.50%,and 90.06%.During composting at 55 °C and at added concentrations of 5 μg·g^(-1),OTC decreased rapidly,and the time required for50% and 90% degradation was 4.1 and 9.8 days,respectively;for TC,these values were 4.4 and 14.0 days,respectively.Removal ef ficiencies for all TCs correlated well with moisture content of the manure.These results show that composting may be a practical and useful means to reduce concentrations of OTC and TC in swine manure prior to its land application.

Investigation on the Veterinary Antibiotics Contamination in Groundwater with SPE-LC/MS/MS

[Objective]The aim is to provide data support for the prevention and control of pollution of exogenous chemical in pig breeding industry.[Methods]Solid-phase extraction（SPE）and tandem mass（LC-MS/MS）were used for determining four classes（tetracyclines,quinolones,macrolides and sulfonamides）of 10 common veterinary antibiotics in groundwater of an important pig breeding base in the Yangtze River Delta region of China.[Results]Results revealed the total concentration of the ten antibiotics in urban rivers ranged from 20.1 ng /L to 61.2 ng /L.The highest proportion was taken by tetracyclines,account for 95%,the concentration was up to 44.0 ng /L.Quinolones shared the second largest proportion of total concentration,about 29%,the concentration was up to 21.6 ng /L,while concentration of sulfonamides and macrolides were respectively below 2.7 ng /L and 6.3 ng /L.The highest total concentration of the ten antibiotics in rural rivers was up to 467 ng /L,60% of which was shared by tetracyclines,the highest concentration of tetracyclines was 253 ng /L.Sulfonamides share 20% of the total concentration,the highest concentration of it was 165 ng /L.The highest concentration of macrolides and quinolones was 14.6 ng /L and 14.5 ng /L,respectively.[Conclusion] Antibiotics＇ pollution in town rivers is more serious than urban rivers＇ pollution caused by antibiotics.

Photocatalytic degradation of tetracycline by copper(I)oxide loaded on Daylily Stalk derived carbon material

In this work,Daylily Stalks derived N doped carbon material(N-DSC)with a high specific surface area was firstly prepared by a chemical activation method,and then cubic Cu_(2)O nanoparticles were combined with the prepared N-DSC to obtain N-DSC/Cu_(2)O composite as the catalyst for the photocatalytic degradation of tetracycline(TC)antibiotics under visible light.It is found that the obtained composite had higher photocatalytic activity than pure Cu_(2)O.Particularly,25 wt%N-DSC/Cu_(2)O composite showed the highest photocatalytic performance with 95%of TC degradation within 100 min and more excellent stability.Combined with various characterizations,it is confirmed that carbon bonds should be conducive to the separation of photoelectron and hole,and the carbon layer with an excellent electrical conductivity on Cu_(2)O can reduce the charge transfer resistance between N-DSC and Cu_(2)O,thereby improving the absorption of visible light and enhancing the photocatalytic activity.Moreover,it is considered that the synergistic effect of photo-generated electron pair in Cu_(2)O and N-DSC could promote the photodegradation efficiency of N-DSC/Cu_(2)O composite.In addition,the active species capture experiment confirmed that·OH and·O_(2)should be the main active species for TC degradation under visible light.This study is expected to provide a novel low-cost photocatalysts for pollutants removal.

Two-dimensional Ti_(3)C_(2)T_(X)-nanosheets/Cu_(2)O composite as a high-performance photocatalyst for decomposition of tetracycline

Construction of photocatalysts with a Schottky heterojunction could realize highly efficient and stable degradation of organic pollutes in the wastewater.In this work,a precipitation method was used to prepare Ti_(3)C_(2)T_(X)-nanosheets/Cu_(2)O composite photocatalysts with the Schottky heterojunction for the decomposition of tetracycline(TC)antibiotics under visible light.As-prepared photocatalysts were characterized by various techniques such as X-ray diffraction analysis(XRD),High resolution transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS).When the best Ti_(3)C_(2)T_(X)-nanosheets/Cu_(2)O composite was applied for the degradation of TC under visible light,the degradation efficiency reached up to 97.6%only in 50 min.It is considered that superoxide radical(O_(2)^(→))and hole(h^(+))were the main reactive species for the TC degradation,and in the Schottky heterojunction,e^(-)-h^(+)pairs in the catalyst could be transferred and separated effectively,resulting in obviously enhanced photocatalytic efficiency and stability.