Search

Tailorable chiral plasmonic nanostructures have attracted great interest due to their potential applications in photonics and sensing. However, there are limited straightforward fabrication routes to modulate the morphology of chiral materials with an external stimulus. Here, a helical assembly of gold nanospheres (AuNSs) is successfully obtained via self‐assembly using glycopeptide helical nanofibers as templates based on electrostatic interactions. The assembly morphology can be readily tailored from short debris to single‐/double‐ and multiple helical threads by changing pHs, resulting in well‐controlled modulation of circular dichroism (CD) in the visible range. Further, this tunable assembly and corresponding chiroptical properties are fully reversible in the pH range from 6 to 10. The electromagnetic simulation revealed how the structural geometries of AuNS helices changed the electromagnetic field propagation pattern to facilitate corresponding chiral optical properties. This approach is a unique and facilely obtained example of chiral nanomaterials with in situ tailoring morphology and chiral properties through external stimulus, demonstrating a potential application for biosensing. [ABSTRACT FROM AUTHOR]

Coal gasification tar residue (CGTR) is a kind of environmentally hazardous byproduct generated in fixed-bed coal gasification process. The CGTR extracted by ethyl acetate was used to prepare powdered activated carbon (PAC), which is applied later for adsorption of phenol. The results showed that the PAC prepared under optimum conditions had enormous mesoporous structure, and the iodine number reached 2030.11 mg/g, with a specific surface area of 1981 m²/g and a total pore volume of 0.92 ml/g. Especially, without loading other substances, the PAC, having a strong magnetism, can be easily separated after it adsorbs phenol. The adsorption of phenol by PAC was studied as functions of contact time, temperature, PAC dosage, solution concentration and pH. The results showed a fast adsorption speed and a high adsorption capacity of PAC. The adsorption process was exothermic and conformed to the Freundlich models. The adsorption kinetics fitted better to the pseudo-second-order model. These results show that CGTR can be used as a potential adsorbent of phenols in wastewater. [ABSTRACT FROM AUTHOR]

Calcium acetate and sodium hydroxide solution with different concentrations mixed with three demineralized low rank bituminous coals were boiled respectively in order to ion exchange with carboxyl and total acids functional groups. The titration end of carboxyl and total acids functional groups were controlled by the pH of calcium acetate solution and phenolphthalein indicator respectively. It showed that correct carboxyl content was obtained at 0.15 mol/L calcium acetate and 2 h boiling time; total acids functional groups were obtained at 0.25 mol/L sodium hydroxide and 1 h boiling time. The carboxyl content was lower than 2 mmol/g and the phenolic hydroxyl content was between 2 and 4 mmol/g; the oxygen in total acids functional groups was more than half in three low rank bituminous coals (dry ashes free basis). An accurate method for measuring acidic functional groups in low rank bituminous coals was obtained. [ABSTRACT FROM AUTHOR]