Nadia Katir

Bismuth is widely recognized for its natural abundance, moderate cost, and low toxicity, making it an attractive alternative to the expensive and toxic transition metals commonly employed in heterogeneous catalysis. In this work, we report the immobilization of bismuth onto a series of SBA-15 materials and their application for nitrophenol reduction and iodine uptake. Particular attention was given to anchoring bismuth on three nitrogen-containing mesostructured silicas in comparison with its deposition on the unmodified silica support. Remarkably, nitrogen-containing ligands directed the nucleation and growth of crystalline bismuth nanosheets, whereas the pristine SBA-15 afforded atomically dispersed and amorphous metal particulates. Bismuth loaded on SBA-NNH₂ represents an optimal balance between porosity, accessibility, and metal–ligand interaction. Crystalline nanosheets displayed interesting catalytic activity for the reduction of nitrophenol to the corresponding aromatic amine, even at low bismuth loading (k_app = 3.8 × 10⁻³ s⁻¹), and exhibited recyclability. Upon reduction, bismuth loaded on SBA-NNH₂ stands as the best scavenger for iodine adsorption, reaching 442 mg.g⁻¹. On the whole, these findings highlight the role of the N-ligands in directing the growth of bismuth particles and the capability of the resulting bismuth-supported materials for iodine scavenging and for sustainable catalysis in fine and pharmaceutical chemistry.

Fish oil byproducts can be upcycled into porous foam composite adsorbents via a one-step process combining reaction with elemental sulfur and in situ exfoliation of montmorillonite or graphene oxide sheets.

Incorporating biotechnologically engineered violacein into chitosan derived from fishery waste yields sustainable food packaging materials with enhanced, multifunctional properties that surpass those of conventional packaging.

Quantum dots (QDs) are promising photocatalysts, primarily investigated in Cd- and Pb-based systems which raise severe toxicity concerns. Indium phosphide (InP) QDs represent an eco-friendly alternative, though their photocatalytic applications remain limited, especially under heterogeneous conditions. We report the first demonstration of InP/ZnS QDs immobilized on mesoporous silica (SBA-15) as recyclable heterogeneous photocatalysts. By tuning particle size and surface ligands, we identify key structure–activity relationships in the benchmark reduction of ferricyanide, with smaller QDs and π-conjugated ligands yielding quantitative conversion. Time-resolved photoluminescence reveals ultrafast charge transfer as the origin of enhanced activity. Immobilization ensures reusability over multiple cycles without loss of performance, establishing InP QDs as robust, sustainable photocatalysts and paving the way for environmentally benign nanomaterials in solar-driven chemistry.

Activated carbon embedded on porous chitosan microspheres perform better than montmorillonite embedded on similar beads for olive mill wastewater treatment.

Several nitrogen-containing organofunctionalized SBA-15-type materials have been successfully prepared, characterized and assessed for methyl orange uptake, antibacterial activity and quercetin release.

Surface functionalization is a key enabler that imparts solid materials with excellent chemoselectivity. With this aim, halloysite and sepiolite clay particles were functionalized with carboxyethylsilanetriol sodium salt (CES) and 3-aminopropyltriethoxysilane (APTES), affording carboxy-terminated and amino-terminated clay, respectively. In the case of halloysite, the grafting occurs at Al-OH groups of the lumen surface (tube inner surface) and Al-OH and Si-OH groups at the edges and external surface defects of the nanotubes. For sepiolite, silanol groups located on the edges of the structural channels were at the origin of a chemical reaction between this fibrous clay and the terminal alkoxysilane. The resulting modified clays were examined for removal of Congo red (CR) and malachite green (MG) as anionic and cationic dyes, respectively. Clay bearing only carboxylic groups display more affinity towards cationic dye (MG), recording 926 mg·g⁻¹ and 387 mg·g⁻¹ for HNT-CES and SEP-CES, respectively, while amino-functionalized clays show very high adsorption for anionic dye (CR), reaching 1232 and 1228 mg·g⁻¹ for HNT-APTES and SEP-APTES, respectively. Simultaneous grafting of the two silyl coupling reagents was also attempted through one-pot and sequential grafting method, with the latter being more appropriate to access amphoteric clay featuring both carboxylic and amino groups. The behavior of the bifunctional adsorbents was investigated with respect to pristine and monofunctional clay. The obtained results provide insights to fulfill the requirement for handling complex water effluent containing both anionic and cationic pollutants, towards more sustainable development.

The interactions between new phosphorylated polysaccharide nanocrystals (cellulose, chitin) and aluminium oxo–hydroxo clusters e-Al₁₃O₄(OH)₂₄(H₂O)₁₂⁷⁺ are investigated and exploited to form mesoporous aluminophosphate materials.

Imidazolium dialkylphosphates were synthesized and used to access nanostructured ionic liquid@TiO₂ hybrid ionogels bridged through P–O–Ti. The dynamicity of these tectonics was explored for exchanging cationic species and for removing micropollutants.