No abstract

Graphical abstract

Potato stems and leaves biochar (PB) was prepared by pyrolysis at a temperature of 500°C under anoxic conditions. In order to strengthen the adsorption capacity, biochar was modified with alkaline solution (alkali modified biochar, APB). Two kinds of biochars were adopted as adsorbents to remove ciprofloxacin (CIP) from aqueous solution. The adsorption behavior of CIP onto biochar before and after alkali modified including adsorption kinetics and isotherms were investigated. The effects of different factors (equilibrium time, pH, temperature and initial concentration) during the adsorption process were also investigated. Biochar samples were characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and nitrogen adsorption-desorption isotherm. The results showed that the alkali treated biochar possessed more mesopores than raw biochar, and accordingly exhibited a more excellent adsorption performance (23.36 mg·g) than raw biochar. Hydrophobic interaction, hydrogen-bonding interaction, electrostatic interaction, and π - π interaction were the adsorption mechanisms for CIP uptake onto the two adsorbents.

An urchin-like chiral metal–organic framework/reduced graphene oxide (urchin-CMOF/rGO) nanocomposite was developed as the electrochemical sensing interface for robust, efficient, and high-selective discrimination of tryptophan (Trp) enantiomers. An urchin-CMOF/rGO nanocomposite was elaborately integrated to combine the amplification of electrical conduction by rGO and the enantioselectivity by asymmetric CMOF. On the basis of this novel nanocomposite-mediated sensor, chiral recognition of d/l-Trp was successfully achieved by the differential potential ratiometric method. Different percentages of Trp racemic mixtures were determined in a good linear relationship with specific peak potentials, which effectively detours the nonspecific signal of concomitant interference from most current-based voltammetries. Even in the complex human cerebrospinal fluid, the simulative ratiometric results of Trp-spiked samples were accurately detected with low false negatives. Additionally, diverse CMOF-regulated hybrid materials have great potential for chiral recognition in pharmaceutical monitoring and biochemical analysis.

No abstract