查找使用阿拉丁产品的科研文献

Post-synthesis of covalent organic frameworks as a hydrophilic platform for specific detection of egg ovalbumin under physiological pH

Quanshou Feng,Zehu Xie,Hongze Liang,Chuan-Fan Ding,Yinghua Yan

Ovalbumin (OVA) is an important protein source in our daily life. Unfortunately, the food safety problem has become more and more serious, such as protein allergy and contaminated protein. Therefore, it is necessary to detect vital proteins efficiently and rapidly. Mass spectrometry (MS) is a powerful tool for the detection of proteins. Herein, dual amino acids functionalized covalent organic frameworks containing disulfide covalent bonds ( [email protected] [email protected] , where G is glutathione and C is cysteine) were facilely prepared for OVA enrichment through hydrophilic interaction liquid chromatography (HILIC) under physiological pH. The results showed that [email protected] [email protected] had displayed sensitive detection (0.1 fmol), good selectivity (OVA: BSA = 1:100), adsorption capacity (311 mg/g), stability, reproducibility, linearity, LOQ level (42 μg/mL) and recovery ratio (64.83 %) for OVA. [email protected] [email protected] also demonstrated satisfactory purification ability in the enrichment of egg white, indicating that [email protected] [email protected] had great potential in the enrichment of protein from complex samples.

Synergizing Fenton oxidation and in-situ coagulation over a wide pH range for the simultaneous removal of multiple pollutants

Ruoyun Lin,Fangjie Lv,Hao Zhang,Yang Li,Jiangang Lu,Jiansheng Li

Efficient removal of multiple pollutants from discharged antibiotic wastewater effluents by a single processing unit is highly desirable, yet challenging. In this study, intrinsically synergizing Fenton oxidation and in-situ coagulation were achieved in the tannic acid (TA)/Fe(III)/H 2 O 2 process, demonstrating the simultaneous removal of multiple pollutants over a wide pH range. Under the optimal conditions (TA/Fe(III)/H 2 O 2  = 25 mg/L/0.1 mM/0.5 mM), 95.43 % of SMR and 98.41 % of turbidity were simultaneously removed at pH = 7. Moreover, the applicability of this process was validated by treating a spiked actual secondary effluent. Compared with polymer ferric sulphate coagulation and conventional Fe(II)/H 2 O 2 Fenton, TA/Fe(III)/H 2 O 2 process exhibited significantly enhanced removal performance in terms of SMR, COD, UV 254 and turbidity without any pH adjustment. The mechanism analysis revealed that the introduction of TA can not only promote the iron redox cycle for the production of ∙OH, but also neutralize the charge for the generation of the porous flocs. Due to the bridging of TA, the synergy of Fenton oxidation and in-situ coagulation was achieved in a single processing unit. Finally, the synergy mechanism proposed that a four-step process sequentially proceeded during the treatment. This study may provide new insights into the simultaneous removal of multiple pollutants in the advanced treatment of refractory industrial wastewater.

Flow-through heterogeneous electro-Fenton based on Co-CNT/Ti3C2TX membrane for improved tetracycline removal in wide pH ranges

Peng Zhang,Yiran Wang,Xiaomin Luo,Jian Wang,Wenqi Wang,Xubin Duan,Kai Qi,Meng Li

The heterogeneous electro-Fenton (HEF) membrane has shown great potential for the treatment of refractory organic pollutants, but there are growing demands to improve its degradation efficiency and suitability for addressing practical organic pollutant issues. Here, a novel Co-CNT/Ti3C2TX nanocomposite membrane was successfully prepared by vacuum filtration, followed by heat treatment. Different from the traditional batch reactor, a flow-through reactor with Co-CNT/Ti3C2TX membrane was designed as an electrode to make the full use of the combined synergistic effect of adsorption and electro-Fenton (EF) process for the degradation of organic pollutants. The results found that the Co-CNT/Ti3C2TX flow-through HEF system exhibited satisfactory degradation (99.0–83.2%) on tetracycline (TC) in a wide range of pH 2.0–7.0. In addition, the obtained Co-CNT/Ti3C2TX membrane possesses self-cleaning performance in long-term continuous conditions. Co-CNT/Ti3C2TX membrane can also be used to treat practical TC wastewater with complex components, tannery printing and dyeing wastewater, and wastewater with different water matrices, and their removal efficiency can reach more than 87.0%. Specially, the coupling effect could be beneficial to accelerate the degradation of pollutants in the EF process. The method provided in this work could be further expanded, making industrial usage of the HEF membrane a reality.

Ag@Pt core-shell icosahedral nanocrystals with solid solution interface improve pH-Universal hydrogen evolution at large current densities

Wen Zhang,Guang-Rui Xu,Qiong Zhang,Yingxiu Zhao,Yanyan Li,Zexing Wu,Jie Liu,Zhenjiang Li,Lei Wang

Industrial application of electrochemical hydrogen production urgently requires the development of highly efficient, stable, and inexpensive electrocatalysts that can drive a large current density. Here, Ag@Pt icosahedral nanocrystals (Ag@Pt icosahedral NCs) catalysts were successfully prepared through one-step solvothermal synthesis for addressing those challenges. The synergies of geometric effect and electronic effect triggered by the discrepancy of different components greatly enhance the electrocatalytic performance in the hydrogen evolution reaction (HER) process at large current densities over wide pH ranges. Excitingly, the Ag@Pt icosahedral NCs could reach 4000 mA cm −2 at 232 mV under the acidic medium and also showed efficient catalytic activity in 1 M KOH and 1 M phosphate buffered saline (PBS) media, improving their potential application in industrialization. Density functional theory (DFT) calculation results show that the electronic synergistic effect brought by the core-shell structure weakens the optimal free energy of hydrogen adsorption (ΔG H* ), promoting the water decomposition kinetics and greatly achieving high catalytic performance.

pH responsive, reversible photo-crosslinkable micelle in layer-by-layer assembly—Study on film growth and drug delivery behavior

Yilin Song,Shuqing Jin,Ke Fu,Jian Ji,Liyan Shen

Layer-by-layer multilayered film has been creating great opportunities in developing controlled drug and other bioactive molecular delivery system. In this work, coumarin bearing micelles of poly(acrylic acid-coumarin methacrylate) is first synthesized in a one-step copolymerization and the reversible photo-crosslinkable multilayers containing coumarin groups are then fabricated via layering the micelles with polyethyleneimine (PEI). The film growth behavior of polyetheleneimine/poly(acrylic acid-coumarin methacrylate) (PEI/P(AA-r-CMA)) multilayer is found to rely on deposit solution pH. Increasing PEI solution pH and decreasing P(AA-r-CMA) pH can greatly accelerate film growing process. This is explained by PEI diffusivity and destabilization of P(AA-r-CMA) micelle at solution/multilayer interface. Nile red (NR) is loaded into the film as a model drug via simple post diffusion driven by hydrophobic interactions. Furthermore, photo-crosslink and decrosslink of PEI/P(AA-r-CMA) film is achieved by irradiating the films with light of 365 and 254 nm wavelength, respectively, which therefore ensures the possibility of fine control over drug delivery procedure. Graphical

Surface Stability and Morphology of Calcium Phosphate Tuned by pH Values and Lactic Acid Additives: Theoretical and Experimental Study

Hongwei Chen,Changchang Lv,Lin Guo,Ming Ma,Xiangfeng Li,Zhengyi Lan,Jun Huo,Hao Dong,Xiangdong Zhu,Qiang Zhu,Yuming Gu,Ziteng Liu,Jianjun Liu,Hangrong Chen,Xuefeng Guo,Jing Ma

The ubiquitous mineralization of calcium phosphate (CaP) facilitates biological organisms to produce hierarchically structured minerals. The coordination number and strength of Ca2+ ions with phosphate species, oxygen-containing additives, and solvent molecules played a crucial role in tuning nucleation processes and the surface stability of CaP under the simulated body fluid (SBF) or aqueous solutions upon the addition of oligomeric lactic acid (LACn, n = 1, 8) and changing pH values. As revealed by ab initio molecular dynamics (AIMD), density functional theory (DFT), and molecular dynamics (MD) simulations as well as high-throughput experimentation (HTE), the binding of LAC molecules with Ca2+ ions and phosphate species could stabilize both the pre-nucleation clusters and brushite (DCPD, CaHPO4·2H2O) surface through intermolecular electrostatic and hydrogen bonding interactions. When the concentration of Ca2+ ions ([Ca2+]) is very low, the amount of the formed precipitation decreased with the addition of LAC based on UV–vis spectroscopic analysis due to the reduced chance for the LAC capped Ca2+ ions to coordinate with phosphates and the increased solubility in the acid solution. With the increasing [Ca2+] concentration, the kinetically stable DCPD precipitation was obtained with high Ca2+ coordination number and low surface energy. Morphologies of DCPD precipitation are in plate, needle, or rod, depending on the initial pH values that were tuned by adding NH3·H2O, HCl, or CH3COOH. The prepared samples at pH ≈ 7.4 with different Ca/P ratios exhibited negative zeta potential values, which were correlated with the surface electrostatic potential distributions and potential biological applications.

A pH-responsive Eu(III) functionalized metal–organic framework hybrid luminescent film for amino acid sensing and anti-counterfeiting

Haifeng Sha,Bing Yan

As the basic units of proteins, the importance of amino acids in organisms is self-evident and therefore detection of the concentration of amino acids is significant in monitoring human health. Herein, a dual-responsive Eu3+-functionalized metal–organic framework (MOFs) luminescent film (1@SA) was designed and prepared, which not only realizes the simultaneous detection of aspartic acid (Asp) and arginine (Arg) but also has the possibility of being applied in anti-counterfeiting. A portable film sensor is obtained through the cross-linking and solidification of Eu3+ ions and sodium alginate (SA) hydrogel containing uniformly dispersed MOFs. The MOF used in this work is a zinc metal–organic framework (ZnMOF) comprising uncoordinated carboxyl groups that can provide binding sites for Eu3+ ions. Moreover, it is found that the sensor shows unique fluorescence changes under the stimulation of an acidic environment. Therefore, the quantitative detection of Asp and Arg by 1@SA can be achieved, and optical anti-counterfeiting platforms are also designed according to the diversity of fluorescence changes. The new strategy proposed in this work may broaden the scope of lanthanide fluorescence films used in optical fields.

3D hierarchical Fe-doped Bi4O5I2 microflowers as an efficient Fenton photocatalyst for tetracycline degradation over a wide pH range

Chenxi Zhu,Yingjun Wang,Longyu Qiu,Yequn Liu,Haibo Li,Yongsheng Yu,Jiaming Li,Weiwei Yang

Fenton reaction is proved to be an efficient method for degrading organic pollutants in wastewater. However, the narrow pH range greatly restricts the application of Fenton reaction. Herein, the 3D hierarchical Fe-doped Bi 4 O 5 I 2 microflowers have been synthesized via a hybrid solvothermal-calcination method and applied in a photo-Fenton system for efficient removal of tetracycline (TC). The optimized Fe-doping Bi 4 O 5 I 2 (11Fe-BOI) microflowers present more than 90% degradation efficiency over the pH range of 3.0–9.0 in Fenton system under visible light irradiation, and the reaction rate constant in 11Fe-BOI/H 2 O 2 /Vis system is 2.79 × 10 −2 min −1 , which is 19.11, 1.85 and 7.71 times higher than that of H 2 O 2 /Vis (1.46 × 10 −3 min −1 ), 11Fe-BOI/Vis (1.51 × 10 −2 min −1 ) and 11Fe-BOI/H 2 O 2 (3.61 × 10 −3 min −1 ) systems, respectively. The synergy effect of photocatalysis and Fenton reaction plays a pivotal role for the TC degradation process via accelerating the separation of carriers and the generation of reactive oxygen species. The scavenging experiments and EPR results manifest that O 2 – and OH are dominant active species during the TC degradation process. This work provides great prospect to fabricate an efficient non-noble metal photocatalyst for photo-Fenton degradation of antibiotics.

Arsenite photo-oxidation and removal by ferrihydrite in the presence of oxalate: a pH dependence and surface-mediated process

Yajie Wang,Xianhe Gong,Xin Dong,Xiuzhen Tao,Yingchun Luo

In this study, the kinetics of arsenite (As(III)) removal in a ferrihydrite/oxalate system under irradiation was investigated, and the effects of pH, ferrihydrite dosage, As(III) initial concentration, and oxalate concentration were evaluated. Ultraviolet A (UVA) irradiation significantly promoted As(III) removal in the presence of ferrihydrite and oxalate. The greatest removal efficiency of As(III) (92.5%) was observed under the following conditions: pH 3.0, 100.0 μg L−1 As(III), 0.0125 g L−1 ferrihydrite, 0.1 mmol L−1 oxalate, and after 90 min under UVA irradiation. The removal of As(III) in the ferrihydrite/oxalate system was strongly pH-dependent. Mechanistic investigations indicated that HO˙ was the primary oxidant for As(III) photo-oxidation in the ferrihydrite/oxalate system. Surface adsorbed hydroxyl radical (HOads˙) was the dominant oxidant over the entire pH range in the presence of oxalate, and the hydroxyl radical in aqueous solution (HOaq˙) made only a small contribution under acidic conditions. The sources of HO˙ were also strongly dependent on pH; HO2˙/O2˙− was the precursor of HO˙ under acidic conditions, while photo-generated holes gradually became the main source of HO˙ as the pH increased. The photo-oxidation of As(III) mainly occurred on the surface of ferrihydrite. Although some ferrihydrite transformed into goethite during the removal process, the iron oxides showed good reusability for up to five regeneration cycles. The findings indicate that As(III) can be efficiently removed by the ferrihydrite/oxalate system and provide guidance for developing effective treatment strategies for As(III)-contaminated waters.

A targeted and efficient CDT system with photocatalytic supplement of H2O2 and hydroxyl radical production at a neutral pH

Xuwen Da,Zhanhua Wang,Yao Jian,Chao Zhang,Yuanjun Hou,Yishan Yao,Xuesong Wang,Qianxiong Zhou

The bottleneck problems of chemodynamic therapy (CDT) are the dependence on an acidic pH (2.0–4.0), insufficient H2O2 level in tumor tissues, and potential systematic toxicity of inorganic nanomaterials-based CDT agents. In this study, the new tricks of two old compounds, i.e. [Ru(phen)2(PIP-OCH3)](PF6)2 (Ru3, phen = 1,10-phenanthroline, PIP-OCH3 = 2-(4-methoxy phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) and Fe(tpy)Cl3 (tpy = 2,2′:6′,2′-terpyridine), were harnessed to construct an ideal CDT system. Ru3 was able to efficiently photo-catalyze NADH oxidation accompanied by the production of H2O2in situ with a high yield of 73.2%, which can be converted into cytotoxic hydroxyl radicals by the biocompatible Fe(tpy)Cl3 at a neutral pH. By loading both Ru3 and Fe(tpy)Cl3 in tumor-targeting bovine serum albumin (BSA), the obtained BSA@Fe/Ru nanoparticles exhibited a highly efficient, selective, and photo-controlled CDT activity both in vitro and in vivo. This work may provide new sights for overcoming the issues confronted in CDT.

Construction of pH-sensitive targeted micelle system co-delivery with curcumin and dasatinib and evaluation of anti-liver cancer

Xiangle Zeng,Yawen Zhang,Xue Xu,Zhuo Chen,Lanlan Ma,Yushuai Wang,Xuliang Guo,Jianchun Li,Xiu Wang

Vinegars inhibiting of the generation of BaP in barbecued pork sausages by decreasing the pH and free radical scavenging

Xiao-min Zhang,Chao-yang Xu,Teng Hui,Ke-zhou Cai,Hui Zhou,Cong-gui Chen,Bao-cai Xu

Benzo[a]pyrene (BaP) is a polycyclic aromatic hydrocarbon (PAH) that has been found in barbecued meat products and has shown carcinogenic properties in humans. The purpose of this study was to investigate the effect of vinegar (fermented vinegars and distilled vinegar) on the generation of BaP in barbecued pork sausages. The results showed that fermented vinegars and distilled vinegar could significantly ( P  < 0.05) inhibit the formation of BaP (26.8%–82.3%) in barbecued pork sausages. Furthermore, fermented vinegar could enhance the sensory evaluation of barbecued pork sausages(tenderness, flavor, juiciness and overall acceptability). Additionally, an intermediate of the Maillard reaction (hydroxymethylfurfural) (0.14–2.34 mg/kg), which is possibly associated with BaP generation, was inhibited because of the decrease in pH. The fermented vinegars, which were rich in phenols (1787.09–3089.60 mg GRE/L) and flavonoid (622.54–2167.97 mg RE/L) compounds, inhibited the formation of BaP by scavenging reactive oxide species (1,1-diphenyl-2-picrylhydrazine (DPPH) radical (85.50–96.73%) and hydroxy free radical (34.56–66.30%) scavenging activities) in pork sausages. Therefore, the vinegars inhibited the content of BaP in barbecued pork sausages by decreasing the pH and scavenging free radicals. In addition, ten phenolic compounds in sun vinegar were confirmed to be critical in inhibiting the content of BaP in barbecued pork sausages. This study provides a more affordable and feasible strategy for the inhibition of BaP in meat processing.