PubMed · 12055033
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2002. Microbicides may be ready.. https://doi.org/10.1089/10872910252972302
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The contamination of water resources by uranyl (UO22+) ions poses significant environmental and health risks, requiring the development of efficient and sustainable remediation strategies. Adsorption-based techniques have emerged as promising approaches in the field of UO22+ removal, but the design of cost-effective, high-capacity, and environmentally friendly adsorbents remains challenging. In this study, a three-dimensional porous nano-hydroxyapatite@gelatin (nHAP@Ge) composite was synthesized through glutaraldehyde cross-linking, combining the structural stability of Ge with the high uranium affinity of nHAP. The optimized nHAP@Ge, with a nHAP:Ge mass ratio of 1:0.5, exhibited exceptional UO22+ removal efficiency (97 %), along with high adsorption capacity (364.03 mg/g). Systematic characterizations using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) methods revealed that the porous structure and surface functional groups (-OH, Ca2+, and PO43-) of the material synergistically contributed to binding UO22+ species. Furthermore, the incorporation of nHAP into the Ge framework resulted in enhanced thermal stability while significantly improving the UO22+ adsorption performance. This work presents a scalable, eco-friendly, and recyclable strategy for the effective treatment of uranium-contaminated water, with potential applications in nuclear wastewater treatment and environmental remediation.
Expanded bed adsorption is an integrated technology that allows the introduction of particle-containing feedstock without the risk of blocking the bed. The biomass particles contained in the feedstock have to be treated as an integral part of the process and potential interactions between suspended biomass and the adsorbent must be excluded during process design. Because the electrostatic forces dominate the interactions between the biomass and adsorbent, the zeta potential has been studied as a tool to characterize biomass/adsorbent electrostatic interactions. The zeta potentials of four types of biomass (yeast intact cells, yeast homogenate, Escherichia coli intact cells, and E. coli homogenate) and two types of ion exchanger were measured systematically at varying process conditions. Using the cell transmission index from biomass pulse-response experiments as a parameter, the relations between zeta potential and the biomass/adsorbent interaction were evaluated. Combining the influences from zeta potential of adsorbent (zeta(a)), zeta potential of biomass (zeta(b)), and biomass size (d), parameter (-zeta(a)zeta(b)d) was found to be an appropriate indicator of the biomass/adsorbent interactions in expanded beds under various liquid-phase conditions for different types of biomass. The threshold value of parameter (-zeta(a)zeta(b)d) can be defined as 120 mV(2) microm for cell transmission of >90%, which means that systems with (-zeta(a)zeta(b)d) < 120 may have a considerable probability of forming stable expanded beds in a biomass suspension under the particular experimental conditions.
In any therapeutic model involving a tissue-engineering approach to the repair of partial-thickness articular cartilage defects, a chondrogenic differentiation factor is required to ensure tissue-specific healing. Transforming growth factor-beta1 (TGF-beta1) is known to act in this capacity, but at such high concentrations as to render its direct injection into the joint cavity inadvisable. This situation calls for a delivery system that can be applied directly to the defect site and that will release the drug gradually over a period of some weeks. Liposome encapsulation represents one such system, and has been recently implemented with some success in an animal model for cartilage repair. However, the kinetics of TGF-beta1 release have not been determined, it was the purpose of the present study to characterize these. The liberation of [(125)I]-labeled TGF-beta1 from fibrin matrices containing this agent in either a free or liposome-encapsulated form was monitored by liquid scintillation counting for 25 days in vitro. During the initial 5 days, fibrin clots containing liposome-encapsulated TGF-beta1 released this cytokine at a slower rate (2% to 4% per day) than did those containing the free molecules (10% to 20% per day); thereafter, the release rates were similar. At the end of the incubation period, only 40% of the liposome-encapsulated TGF-beta1 had been released from the fibrin clots, as compared with 68% from those containing the free molecules. Liposome encapsulation thus represents a suitable means of establishing a slow-delivery system in tissue-engineering approaches to articular cartilage repair.