Evaluation of dry protonated calcium alginate beads for biosorption applications and studies of lead uptake

Alginate polysaccharide is a promising biosorbent for metal uptake. Dry protonated calcium alginate beads for biosorption applications were prepared, briefly characterized and tested for lead uptake. Several advantages of this biosorbent are reported and discussed in comparison with other alginate-based sorbents. The alginate beads contained 4.7 mmol/g of COOH groups, which suffered hydrolysis near pH 4. The Weber and Morris model, applied to kinetic results of lead uptake, showed that intraparticle diffusion was the rate-controlling step in lead sorption by dry alginate beads. Equilibrium experiments were performed and the data were fitted with different isotherm models. The Langmuir equation was the most adequate to model lead sorption. The maximum uptake capacity (qmax) was estimated as 339 mg/g and the Langmuir constant (b) as 0.84 l/mg. These values were compared with that of other sorbents found in the literature, indicating that dry protonated calcium alginate beads are among the best biosorbents for the treatment and recovery of heavy metals from aqueous streams.

The role of additive manufacturing in patient specific solutions

This dissertation investigates de role of the new additive manufacturing techniques in the treatment of pathologies with a patient-specific approach. Throughout this work the development methodology of these said products is explained in order to understand the different stages required to achieve a tailor made solution. The goal is to demonstrate the importance of the manufacturing technique and its capabilities to tailor-fit devices to patients and the adaptability of the process to tackle the most diverse situations. Three real cases are documented in order to prove the viability of the method and to showcase its advantages. Whenever possible patient-specific solutions are compared to their “off-the-shelf” counterparts in order to establish the pros and cons of each one of them. The dissertation is an insight into a possible future for the medical devices industry, where customization is expected to be the standard approach in the treatment of patients.