Designing of a cellulose-based ion-imprinted biosorbent for selective removal of lead (II) from aqueous solutions.

Developing an effective adsorbent for Pb2+ removal from wastewater has huge economic and environmental implications. Adsorbents made from cellulosic materials that have been modified with certain chelators could be used to get rid of metal cations from aqueous solutions. However, their selectivity for specific metals remains very low. Here, we describe the synthesis of 4-(2-pyridyl)thiosemicarbazide (PTC) hydrazidine-functionalized cellulose (Pb-PTC-CE), a polymer imprinted with Pb2+ ions that may be used to remove Pb2+ ions from wastewater. Owing to its potent -NH2 functionalization, PTC hydrazidine not only served as an efficient chelator to effectively supply coordinating sites and construct hierarchical porous structures on Pb-PTC-CE, but it also made it possible for cross-linking to occur through the glyoxal cross-linker. The abundant chelators, along with the hierarchical porous construction of the developed Pb-PTC-CE with PTC functionality, result in a greater sorption capacity of 336 mg/g and a short sorption period of 40 min for Pb2+. Additionally, Pb-PTC-CE exhibits highly selective Pb2+ uptake compared to competing ions. This study proposes a feasible methodology for the development of high-quality materials for Pb2+ remediation by combining the advantages of active ligand functionality with ion-imprinting techniques in a straightforward way.

Synthesis and characterization of gellan gum-based hydrogels for drug delivery applications.

In this study, gellan gum (Gel) derivatives were allowed to interact via aqueous Diels-Alder chemistry without the need for initiators, producing a crosslinked hydrogel network that exhibited good potential as a drug carrier using tramadol as a drug model. Hydrogel conjugation was achieved by the synthesis of a maleimide and furan-functionalized Gel, and the pre- and post-gelation chemical structure of the resulting hydrogel precursors was fully investigated. Potential uses of the developed hydrogel in the pharmaceutical industry were also evaluated by looking at its gelation duration, temperature, morphologies, swelling, biodegradation, and mechanical characteristics. The Gel-FM hydrogels were safe, showed good antimicrobial activity, and had a low storage modulus, which meant that they could be used in many biochemical fields. The encapsulation and release of tramadol from the hydrogel system in phosphate-buffered saline (PBS) at 37 °C were investigated under acidic and slightly alkaline conditions, replicating the stomach and intestinal tracts, respectively. The in-vitro release profile showed promising results for drug encapsulation, revealing that the drug could safely be well-encapsulated in acidic stomach environments and released more quickly in slightly alkaline intestinal environments. This implies that the hydrogels produced could work well as polymers for specifically delivering medication to the colon.