Ternary MIL-100(Fe)@Fe3O4/CA magnetic nanophotocatalysts (MNPCs): Magnetically separable and Fenton-like degradation of tetracycline hydrochloride

Today’s world, tetracycline hydrochloride (TC) is considered as a Compounds of Emerging Concern (CECs). Metal-organic frameworks MOFs with a microporous structure and holding larger pores indicating potential applications in the fields of environmental purification. Recently, carbon aerogel (CA) has also aroused great interest due to its larger specific surface area, low density, thermal stability, and non-toxicity. Herein, MIL-100(Fe) was synthesized under low temperature and combined with Fe₃O₄ and CA, respectively. The obtained MIL-100(Fe), MIL-100(Fe)@Fe₃O₄, MIL-100(Fe)@CA and MIL-100(Fe)@Fe₃O₄/CA were investigated as a photocatalyst for removal of TC from the water. The results indicated that the MIL-100(Fe)@Fe₃O₄/CA degrade TC up to 85%, which is much higher than MIL-100(Fe)@Fe₃O₄ (c.a. 42%), due to its high surface area 389?m²?g^?1, smaller pore size and pore volume 2.4?nm and 0.319?m³?g^?1, high separation of electron and hole, and lower band gap of 1.76?eV. The coupling of CA with MIL-100(Fe)@Fe₃O₄ considerably accelerate the transfer of photo-generated charge carriers and enhanced 1.6 times the performance of MIL-100(Fe)@Fe₃O₄. Furthermore, the stability and recyclability were enhanced due to the addition of Fe₃O₄, facilitating the environmentally friendly water purification processes.     

LaMnO3/GA复合材料活化PMS降解四环素的性能和反应机制探究

本研究采用溶胶凝胶法和水热法制备了石墨烯气凝胶(GA)负载的LaMnO₃复合催化剂,研究了其对过一硫酸盐(PMS)降解四环素(TC)的催化性能。采用SEM、TEM、XPS、拉曼光谱等手段对样品的形貌结构、元素组成和化学形态进行了表征,结果显示构成了LaMnO₃/GA复合催化剂。实验结果表明,与LaMnO₃纯样相比(降解率为58%),LaMnO₃/GA25复合材料活化PMS降解TC的催化性能可提高至83%以上。这种增强效果可归因于GA的引入,加快了电荷的迁移速率并提升了活性位点的电荷浓度。自由基捕获试验验证了O₂•⁻, ¹O₂, •OH作为活性物质在TC降解过程中的重要性。此外,通过探究LaMnO₃/GA25/PMS体系对多种无机阴离子(如${{text{H}}_{text{2}}}text{PO}_{text{4}}^{{-}} $, $text{SO}_{text{4}}^{{2-}} $, Cl⁻, Urea, $text{HCO}_{text{3}}^{{-}} $)和腐殖酸(HA)的抗干扰活性以及和循环使用性能,证明了LaMnO₃/GA25/PMS体系用于复杂水体中污染物处理的可行性,并为充分利用锰矿资源解决环境污染问题提供了新的思路。     

A novel poly(triazine imide) hollow tube/ZnO heterojunction for tetracycline hydrochloride degradation under visible light irradiation

A novel poly(triazine imide) hollow tube (PTI)/ZnO heterojunction was prepared by a molten salts method. The photocatalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy, respectively. The results showed the ZnO nanoparticles were successfully coupled into the PTI hollow tube to form PTI/ZnO heterojunction. The degradation of tetracycline hydrochloride (TC) under visible light irradiation was used to evaluate the activity of photocatalyst. The PTI/ZnO-6?wt% heterojunction exhibits the highest photocatalytic activity, which can degrade almost all TC within 90?min. The kinetic constant of degradation reaction with PTI/ZnO-6?wt% heterojunction (0.034?min^?1) is about 5 times as high as that of the PTI (0.0070?min^?1). A possible photocatalytic mechanism for heterojunction according to the energy-band theory was proposed.     

Development of local injectable dental gel: the influence of certain additives on physicochemical properties of glycerylmonooleate-based formulations

The current research study is based on the design and development of a sol-gel biodegradable controlled-release formulation for use in the treatment of periodontal diseases. Glycerylmonooleate (GMO) was used as a main composition in the gel base. The influence of various additives, e.g., glycerylmonostearate (GMS), methylcellulose (MC), surfactants, and triglycerides, in GMO formulations on rheologic and swelling properties and release characteristics was described. It was demonstrated that the surfactants and triglycerides affected rheologic behavior, whereas GMS and MC influenced both rheologic and swelling properties of the bases. The release study revealed that drug released from the gel bases depended on the square root of time. The kinetics can be explained by the Higuchi's diffusion theory. Some polyols could enhance drug release from the gel. The stability results suggested that the dental gels obtained should be kept in the low temperature range.     

Development of Local Injectable Dental Gel: The Influence of Certain Additives on Physicochemical Properties of Glycerylmonooleate‐Based Formulations

The current research study is based on the design and development of a sol‐gel biodegradable controlled‐release formulation for use in the treatment of periodontal diseases. Glycerylmonooleate (GMO) was used as a main composition in the gel base. The influence of various additives, e.g., glycerylmonostearate (GMS), methylcellulose (MC), surfactants, and triglycerides, in GMO formulations on rheologic and swelling properties and release characteristics was described. It was demonstrated that the surfactants and triglycerides affected rheologic behavior, whereas GMS and MC influenced both rheologic and swelling properties of the bases. The release study revealed that drug released from the gel bases depended on the square root of time. The kinetics can be explained by the Higuchi's diffusion theory. Some polyols could enhance drug release from the gel. The stability results suggested that the dental gels obtained should be kept in the low temperature range.     

Removal of antibiotics by coagulation and granular activated carbon filtration

Treatment of seven tetracycline classes of antibiotic (TAs) from raw waters (synthetic and river) was evaluated using coagulation and granular activated carbon (GAC) filtration in this study. Both coagulation and GAC filtration were effective for removal of TAs, and the removal efficiency depended on the type of TAs. GAC filtration was relatively more effective for removal of tetracycline (TC), doxycycline-hyclate (DXC), and chlortetracycline-HCl (CTC), which were difficult to remove by coagulation. It was speculated that TAs would be removed through the charge neutralization and sweep coagulation when poly-aluminum chloride (PACl) was added into the raw waters. The charge neutralization of zwitterionic or negative TAs by cationic Al (III) species drove removal of TAs from the synthetic water. When sufficient alkalinity was available (river water), aluminum hydroxide precipitates were formed. TAs could be removed by being enmeshed into or adsorbed onto the precipitates when PACl was added to the river water.     

Enhanced visible light photocatalytic activity in AgI/BiOCOOH composite

AgI/BiOCOOH composite photocatalysts have been synthesized via a simple deposition-precipitation method. The crystal structure, microstructure, element valance, light and electrical properties of as prepared samples were characterized by XRD, SEM, TEM, XPS, UV–Vis DRS, PL, EIS and photocurrent response. The loading of AgI nanoparticles endowed BiOCOOH with good visible light absorption and photocatalytic activity for degrading rhodamine B. The composition with Ag:Bi?=?1:1 exhibited the best photocatalytic activity. The enhanced photocatalytic performance could be mainly attributed to the effective separation of the photogenerated carriers at the heterojunction. O^2? and h⁺ were suggested as the main reactive species in the photocatalytic reaction. In addition, the photocatalysts showed excellent stability over multiple reaction cycles.     

Microwave-assisted method for preparation of Zn1−xMgxO nanostructures and their activities for photodegradation of methylene blue

Nanostructures of Zn_1−xMg_xO (0 ⩽ x ⩽ 0.2) were prepared in water by one-pot method under microwave irradiation for 5 min. In this method, zinc acetate, magnesium nitrate and sodium hydroxide were used as starting materials without using any additive and post preparation treatment. The nanostructures were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS), electrochemical impedance spectroscopy (EIS), Fourier transform-infrared (FT-IR), and the Brunauer–Emmett–Teller (BET) techniques. The nanostructures have wurtzite hexagonal crystalline phase and doping of Mg²⁺ ions does not change the phase of ZnO. The SEM and TEM images show that morphology of the samples is changing by doping of Mg²⁺ ions. The EIS data show that by doping the ion, interfacial charge transfer resistance of the nanostructures decreases. Photocatalytic activity of the nanostructures was evaluated by degradation of methylene blue (MB) under UV irradiation. The degradation rate constant on the nanostructures with 0.15 mol fraction of Mg²⁺ ions is about 2-fold greater than for ZnO. Moreover, influence of various operational parameters such as microwave irradiation time, calcination temperature, weight of catalyst, concentration of MB, pH of solution and scavengers of reactive species on the degradation rate constant was investigated and the results were discussed.     

The acidic complexation of tetracycline with sucralfate for its mucoadhesive preparation

The complex of antibiotics with sucralfate (SF) was prepared with acid. The mechanism of the complexation and some factors concerning the preparation, which influence the mucoadhering property, were studied. The complexation was confirmed by the change in color and instrumental analysis. The acidic complex appeared to be produced by reagglomeration of SF preliminary particles. It was suggested that the amide or amine groups of tetracycline (TC) and aluminum moieties of SF serve as the binding sites. The potential of multiple binding sites and a priority in them were suggested by the Scatchard plot analysis. The additional amounts of acid and the increase in the surface area increased the number of sites. The amount of the additional acid appeared to be the most important factor during the preparation of the acidic complex. The appropriate amount of acid added appeared to produce a complex rich in TC. However, an excess amount might cause the excess dissociation of aluminum moieties, which destroys the mucoadhesive paste-forming property.