Adsorption of cationic methylene blue dye using microwave-assisted activated carbon derived from acacia wood: Optimization and batch studies

This study assesses the performance of optimized acacia wood-based activated carbon (AWAC) as an adsorbent for methylene blue (MB) dye removal in aqueous solution. AWAC was prepared via a physicochemical activation process that consists of potassium hydroxide (KOH) treatment, followed by carbon dioxide (CO₂) gasification under microwave heating. By using response surface methodology (RSM), the optimum preparation conditions of radiation power, radiation time, and KOH-impregnation ratio (IR) were determined to be 360 W, 4.50 min, and 0.90 g/g respectively, which resulted in 81.20 mg/g of MB dye removal and 27.96% of AWAC’s yield. Radiation power and IR had a major effect on MB dye removal while radiation power and radiation time caused the greatest impact on AWAC’s yield. BET surface area, mesopore surface area, and pore volume of optimized AWAC were found to be 1045.56 m²/g, 689.77 m²/g, and 0.54 cm³/g, respectively. Adsorption of MB onto AWAC followed Langmuir and pseudo-second order for isotherm and kinetic studies respectively, with a Langmuir monolayer adsorption capacity of 338.29 mg/g. Mechanism studies revealed that the adsorption process was controlled by film diffusion mechanism and indicated to be thermodynamically exothermic in nature.     

Facile preparation of MgAl2O4/CeO2/Mn3O4 heterojunction photocatalyst and enhanced photocatalytic activity

Novel Mn₃O₄-promoted double p?n junction MgAl₂O₄/CeO₂/Mn₃O₄ heterojunction photocatalyst was constructed by one-step synthesis method and two-step synthesis method. The X-ray powder diffraction, Fourier transform infrared spectrum, X-ray photoelectron spectroscopy, optical and photoluminescence demonstrated that the MgAl₂O₄/CeO₂/Mn₃O₄ heterojunction photocatalyst was synthesized by the two-step synthesis method comprehends a high crystallinity, charge carrier migration and separation efficiency, and relatively low optical absorption coefficient. The MgAl₂O₄/CeO₂/Mn₃O₄ heterojunction photocatalysts were efficiently used as simulated sunlight-driven n-n and p-n double junction photocatalyst for the simultaneous degradation of methylene blue (MB) dye. The continuous double p?n junction MgAl₂O₄/CeO₂/Mn₃O₄ heterojunctions strengthened the function of single n-n or p-n junction and guided the charge carrier migration and separation direction; thus, the oxidation and reduction reactions occur at the active site of spatial separation and prevent the recombination of electrons and holes. The results suggest that the continuous double p?n junction MgAl₂O₄/CeO₂/Mn₃O₄ heterojunctions are very promising candidate material for enhancing the photocatalytic activity in the photocatalytic degradation of MB dye.     

“蓝瓶子”实验再探究*

利用SPSS 25.0统计软件对“蓝瓶子”实验进行正交实验设计,通过统计学分析得出最佳实验条件。利用氧化还原传感器(ORP)对“蓝瓶子”振荡体系的电极电势变化曲线进行分析,并针对蓝色的产生和消失过程设计3组对比实验深入探究,阐明其反应原理,意在引导学生深刻理解趣味实验现象背后的微观反应本质。     

指导本科生课外科研实践活动*——“我爱实验室”有感

由南开大学化学学院科技创新协会面向低年级本科生举办的“我爱实验室”活动,旨在拓宽学生的专业知识领域、使学生深入了解科研前沿方向、培养学生科研素养等。基于实验室的研究方向,学生自主调研文献选题、设计实验过程、参与组会沟通、交流并解决实验中遇到的问题。课外科研实践活动的开展不仅提高了学生的实验技能,而且拓宽了学生的知识领域,更重要的是培养和提高学生进行科学研究的素养和能力。     

Bimetallic CuCo Derived from Prussian Blue Analogue for Nonenzymatic Glucose Sensing

Bimetallic CuCo composites are prepared by calcinating copper hexacyanocobaltate precursor in N₂ atmosphere. The CuCo modified electrodes are fabricated for nonenzymatic glucose sensing in the alkaline electrolyte. The glucose can be directly electro-oxidized on the surface of the electrode catalyst mediated by the redox couples of Cu and Co. The optimal glucose sensor exhibits a high sensitivity (567 μA ⋅ mM⁻¹ ⋅ cm⁻²) in the range up to 825 μM with a detection limit of 3 μM and acceptable selectivity. The sensor can also be applied in serum samples. This work provides a facile and easily-scalable synthesis method of electrocatalysts for nonenzymatic glucose sensors.     

Gold Nanowires – Assisted Prussian Blue Enhancing Peroxidase – Like Activity for the Non-enzymatic Electrochemically Sensing H2O2 Released From Living Cells

Prussian blue nanoparticles (PBNPs) have peroxidase-like activity for H₂O₂. However, PB alone have poor electrochemical performances. Herein, a strategy was proposed by direct in-situ growth PBNPs onto gold nanowires (AuNWs) surface to obtain the peroxidase-like activity with about 4.05 times higher than that of PBNPs alone. PBNPs@AuNWs was employed to construct a non - enzymatic electrochemical H₂O₂ sensor with the detection limit of 5.3×10⁻⁹ mol/L (S/N=3). The sensor was successfully used to detect H₂O₂ in human serum samples or secreted from living HeLa cells. It may be a competitive candidate for H₂O₂ assaying in biological samples or cellular investigation.     

Hydrogen Peroxide Detection Using Prussian Blue-modified 3D Pyrolytic Carbon Microelectrodes

A highly sensitive amperometric Prussian blue-based hydrogen peroxide sensor was developed using 3D pyrolytic carbon microelectrodes. A 3D printed multielectrode electrochemical cell enabled simultaneous highly reproducible Prussian blue modification on multiple carbon electrodes. The effect of oxygen plasma pre-treatment and deposition time on Prussian blue electrodeposition was studied. The amperometric response of 2D and 3D sensors to the addition of hydrogen peroxide in μM and sub-μM concentrations in phosphate buffer was investigated. A high sensitivity comparable to flow injection systems and a detection limit of 0.16 μM was demonstrated with 3D pyrolytic carbon microelectrodes at stirred batch condition     

P‐type tin‐oxide thin film transistors for blue‐light detection application

We reported the characteristics of p‐type tin‐oxide (SnO) thin film transistors (TFTs) upon illumination with visible light. Our p‐type TFT device using the SnO film as the active channel layer exhibits high sensitivity toward the blue‐light with a high light/dark read current ratio (I_light/I_dark) of 8.2 × 10³ at a very low driven voltage of <3 V. Since sensing of blue‐light radiation is very critical to our eyes, the proposed p‐type SnO TFTs with high sensitivity toward the blue‐light show great potential for future blue‐light detection applications.

     

An efficient and practical synthesis of methylene dioximes by combination of ultrasound and phase transfer catalyst

The reaction of oximes with dichloromethane was carried out in 71–98% yields at 20–30 °C for 2–3.5 h in the presence of sodium hydroxide by combination of benzyldimethyltetradecylammonium chloride and ultrasonication. The main advantage of the present procedure is that the reaction time is much shorter than classical methods.     

几种光产酸剂产酸效率的测定

溴酚兰水溶液的紫外吸收会随着体系中含酸的量发生变化,在440 nm吸收峰处一定浓度范围内溴酚兰水溶液的吸光度与溶液中酸浓度成正比,可由此测定酸浓度.用这种方法测定了3种不同类型的光产酸剂在聚乙二醇膜层中在低压汞灯(254 nm)照射下的产酸量.其中三嗪光产酸剂的光照产酸能力最强.