Adsorption kinetics and isotherms of berberine by ZSM-5 molecular sieves from Cortex Phellodendron

Facile fabrication of chitosan-based molecular imprinted microspheres to adsorb selectively, release and anti-bacteria for berberine

Berberine hydrochloride (Ber), a bioactive compound widely found in the roots, rhizomes, stems and barks of Coptis chinensis, has demonstrated efficacy in treating many diseases, such as cancer, congestive heart failure, Alzheimer's disease, especially inflammatory caused by bacteria. The molecularly imprinted microspheres based on chitosan were fabricated to adsorb selectively, release and anti-bacteria of Ber. The Ber surface molecularly imprinted microspheres (Ber-PSSS@GCS-MIPs) were synthesized using crosslinked chitosan as matrix, Ber as template, and sodium 4-styrene sulfonate (SSS) as functional monomer via a redox surface-initiating system -NH2/-S2O82-. The microspheres were characterized by fourier transform infrared reflection (FTIR), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Adsorption kinetics, isotherms and imprinting factor were investigated, and the drug release performance and antibacterial activity were evaluated. As a result, via electrostatic interaction and "lock-key" imprinted cavities, the adsorption capacity of Ber-PSSS@GCS-MIPs reaches 185 mg/g at 2 h, significantly higher than 51 mg/g observed for non-imprinted microspheres. The adsorption of Ber-PSSS@GCS-MIPs. follows pseudo-second-order kinetics, with adsorption amount decreasing as temperature increases and salt concentration rises. Ber-PSSS@GCS-MIPs show excellent recognition and selectivity with an imprinting factor of 3.07, a selectivity factor exceeding to 2. The adsorption capacity remains at 82.4 % of three times cycles. The Ber-PSSS@GCS-MIPs loaded drug microspheres attain slow and sustained release for 70 % at 139 h. The relative antibacterial rate of Ber-PSSS@GCS-MIPs loaded Ber is higher than non-imprinted microsphere and control against S. aureus and E. coli.

Unraveling the Origin of Enhanced Activity of the Nb2O5/H2O2 System in the Elimination of Ciprofloxacin: Insights into the Role of Reactive Oxygen Species in Interface Processes

The overlooked role of reactive oxygen species (ROS), formed and stabilized on the surface of Nb₂O₅ after H₂O₂ treatment, was investigated in the adsorption and degradation of ciprofloxacin (CIP), a model antibiotic. The contribution of ROS to the elimination of CIP was assessed by using different niobia-based materials in which ROS were formed in situ or ex situ. The formation of ROS was confirmed by electron paramagnetic resonance (EPR) and Raman spectroscopy. The modification of the niobia surface charge by ROS was monitored with zeta potential measurements. The kinetics of CIP removal was followed by UV-vis spectroscopy, while identification of CIP degradation products and evaluation of their cytotoxicity were obtained with liquid chromatography-mass spectrometry (LC-MS) and microbiological studies, respectively. Superoxo and peroxo species were found to significantly improve the efficiency of CIP adsorption on Nb₂O₅ by modifying its surface charge. At the same time, it was found that improved removal of CIP in the dark and in the presence of H₂O₂ was mainly determined by the adsorption process. The enhanced adsorption was confirmed by infrared spectroscopy (IR), total organic carbon measurements (TOC), and elemental analysis. Efficient chemical degradation of adsorbed CIP was observed upon exposure of the Nb₂O₅/H₂O₂ system to UV light. Therefore, niobia is a promising inorganic adsorbent that exhibits enhanced sorption capacity toward CIP in the presence of H₂O₂ under dark conditions and can be easily regenerated in an environmentally benign way by irradiation with UV light.

Studies on Adsorption Kinetics and Thermodynamics of Macroporous Resin for Rosmarinic Acid

This experiment treated perilla seeds with different concentrations of NaCl solution to enrich and purify their rosmarinic acid (RosA). The results showed that low concentrations of salt (0-20 mmol/L) promoted seed germination, while high concentrations (> 20 mmol/L) inhibited germination. When the salt concentration was 20 mmol/L, the germination rate was the highest. The content of RosA in germinated perilla seeds was 3.5 mg/g, which was 3.5 times as much as that in the seeds without germination. The RosA was purified using NK-109 macroporous resin and its adsorption kinetics, isotherms and thermodynamics were determined. The adsorption kinetics showed that the adsorption behavior of RosA in NK-109 resin conformed to the pseudo-second-order kinetic model. The model for RosA in the NK-109 resin exhibited Langmuir adsorption based on a spontaneous exothermic process according to its adsorption thermodynamics, which included both physical and chemical adsorption. The optimized process conditions were as follows: the loading concentration of 0.04 mg/mL, loading volume of 40 mL, 70% methanol as the eluent with the volume of 60 mL, and the purity of RosA was 42.1%.

Removal of Berberine from Wastewater by MIL-101(Fe): Performance and Mechanism

The water contamination from pharmaceuticals and personal care products (PPCPs) has attracted worldwide attention in recent years because of its threat to public health. Berberine is a typical anti-inflammatory medicine and berberine wastewater is difficult to be treated due to its high toxicity, poor biodegradability, and high acidity. Metal-organic frameworks would be a good choice to remove berberine from wastewater due to its advantages of high specific surface area, ultrahigh porosity, and structural and functional tunability. In this study, MIL-101(Fe) was synthesized and used for the removal of berberine from water. Experimental results indicated that MIL-101(Fe) showed promising characteristics when berberine was adsorbed in acidic wastewater. The high concentration of chloride in berberine wastewater could promote the adsorption of berberine by MIL-101(Fe). Fitting of batch equilibrium data showed that MIL-101(Fe) had a maximum adsorption capacity of 163.93 mg/g for berberine removal at pH 7, and the berberine sorption on MIL-101(Fe) followed the pseudo-second-order model. Furthermore, the associate mechanism for berberine removal was proposed by characterizing the material and theoretical calculation. The X-ray power diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analysis showed that no chemical reaction occurred during the adsorption of berberine by MIL-101(Fe). Also, the theoretical calculation results indicated that π-π interactions may play the main role in the adsorption of berberine onto MIL-101(Fe). The findings of this study suggest that MIL-101(Fe) is a promising sorbent for berberine removal from wastewater.