Microwave-assisted hydrothermal synthesis and adsorption properties of carbon nanofibers for methamphetamine removal from aqueous solution using a response surface methodology

Versatile Carbon Nanofiber-Based Sensors

Carbon nanofibers (CNFs) display colossal potential in different fields like energy, catalysis, biomedicine, sensing, and environmental science. CNFs have revealed extensive uses in various sensing platforms due to their distinctive structure, properties, function, and accessible surface functionalization capabilities. This review presents insight into various fabrication methods for CNFs like electrospinning, chemical vapor deposition, and template methods with merits and demerits of each technique. Also, we give a brief overview of CNF functionalization. Their unique physical and chemical properties make them promising candidates for the sensor applications. This review offers detailed discussion of sensing applications (strain sensor, biosensor, small molecule detection, food preservative detection, toxicity biomarker detection, and gas sensor). Various sensing applications of CNF like human motion monitoring and energy storage and conversion are discussed in brief. The challenges and obstacles associated with CNFs for futuristic applications are discussed. This review will be helpful for readers to understand the different fabrication methods and explore various applications of the versatile CNFs.

Optimization of Pb(II) ions adsorption on nanohydroxyapatite adsorbents by applying Taguchi method

This paper presents an optimization approach for the removal of lead ions (Pb⁺²) by nano-hydroxyapatite powder form adsorbents that were produced from bovine bone by mechanical activation method. The Taguchi method was implemented for designing the experiments by considering four controllable factors including (1) ball milling time (A), (2) the initial concentration of lead ions (B), (3) initial pH of the solution (C); and (4) the adsorbent dosage (D), each factor at four different levels. According to the ANOVA analysis results, the removal efficiency of the lead ions was predominantly influenced by the adsorbent dosage (38.2%) and the initial lead ions concentration (23.64%), whereas the effect of initial pH of the solution was ignorable and the ball milling time had a mild contribution of 14.79%. The total optimum adsorptive lead ions removal of 100% was achieved by optimization process at operating conditions of C_o = 180 mg L^{- 1}, ball milling time = 2 h, pH = 3, and adsorbent dosage = 0.15 g. The Langmuir isotherm model fitted to the equilibrium results with good accuracy and a maximum sorption capacity of 200 mg g^-1 was predicted by the model for the hydroxyapatite adsorbent ball milled for 2 h.

Study on jet aeration oxidation of magnesium sulfite from magnesium-based exhaust gas cleaning system

Oxidation of magnesium sulfite in washing water is essential for the treatment of by-product of shipboard magnesium-based exhaust gas cleaning systems. The purpose of this study is to obtain a highly efficient magnesium sulfite oxidation technology by using the jet aeration process. Response surface methodology and central composite design were used to investigate the effects of major variables on oxidation of magnesium sulfite and optimize the oxidation conditions. The predictions of the two response functions agree well with the experimental data. The optimum oxidation conditions for ship are temperature 318 K, liquid flow rate 4.04 m³/h, and pH 7.70. Under optimal conditions, 12 moles of magnesium sulfite were oxidized by 90% over 15 minutes at an energy consumption of 0.220 kw h.

Molecular aspects of core-shell intrinsic defect induced enhanced antibacterial activity of ZnO nanocrystals

AIM

To investigate molecular aspects of the antibacterial effect of size-dependent core-shell intrinsic defects of nanocrystalline ZnO synthesized through high energy ball milling technique.

MATERIALS & METHODS

Mechanically synthesized and characterized 7, 10 and 15 h milled ZnO nanoparticles were evaluated for antibacterial activity with molecular investigation by computational molecular docking.

RESULTS

Synthesized ZnO nanoparticles displayed shrinkage of core and increase of shell with reduction in size of bulk ZnO particles from 250 to 80, 40 and 20 nm and increase in zeta potential up to -19 mV in 7, 10 and 15 h nano ZnO. Antibacterial activity was found increased with decrease in size due to increased reactive oxygen species and membrane damage in bacteria.

CONCLUSION

Synthesized nano ZnO exhibit size-dependent antibacterial action as consequences of interactions with cell membrane proteins via hydrogen bond interaction with amino acid residues followed by internalization, membrane depolarization and induction of reactive oxygen species generation.