In low- to middle-income communities, the lack of affordability of conventional sanitary products during menstrual cycles can cause psychological and health issues, ultimately affecting their quality of life. It is crucial to develop alternative products that are affordable and accessible to all while also promoting menstrual health and hygiene. Super absorbent polymers (SAPs) are a vital component in current disposable sanitary pads and nappies. However, these SAPs are often non-biodegradable and non-biocompatible. Therefore, the use of eco-friendly materials for the production of SAPs is gaining popularity in the hygiene industry, as it offers a means to reduce the carbon footprint and environmental impact associated with traditional SAPs made from non-renewable petroleum-based materials. SAPs made from polysaccharides often have naturally occurring antibacterial properties, making them appealing for commercial applications in sanitary products such as sanitary pads. In addition, the move toward reusable sanitary pads with antibacterial properties can significantly reduce waste generated by single-use products and prevent the growth of bacteria, improving the safety and hygiene of the product. Furthermore, computational modeling and artificial intelligence are now important tools in SAP synthesis, providing advantages such as predicting polymer properties, rationalizing synthesis pathways, and improving quality control. These tools can reduce synthesis costs by eliminating the need for trial-and-error approaches in polymer synthesis, ultimately promoting more affordable products for end users. Overall, these advancements in polymer synthesis and material design can help to create a more sustainable industry and promote menstrual hygiene and product accessibility to those who need it most.

Metal organic frameworks (MOFs) are porous hybrid crystalline materials that consist of organic linkers coordinated to metal centres. The trans–cis isomerisation kinetics of the azobenzene-4,4′-dicarboxylic acid (AZB(COOH)₂) precursor, as well as the Al³⁺ (Al-AZB)- and Zr⁴⁺ (Zr-AZB)-based MOFs with azobenzene-4,4′-dicarboxylate linkers, are presented. The photo-isomerization in the MOFs originates from singly bound azobenzene moieties on the surface of the MOF. The type of solvent used had a slight effect on the rate of isomerization and half-life, while the band gap energies were not significantly affected by the solvents. Photo-responsive MOFs can be classified as smart materials with possible applications in sensing, drug delivery, magnetism, and molecular recognition. In this study, the MOFs were applied in the dye adsorption of congo red (CR) in contaminated water. For both MOFs, the UV-irradiated cis isomer exhibited a slightly higher CR uptake than the ambient-light exposed trans isomer. Al-AZB displayed a dye adsorption capacity of over 95% for both the UV-irradiated and ambient light samples. The ambient light exposed Zr-AZB, and the UV irradiated Zr-AZB had 39.1% and 44.6% dye removal, respectively.

The increasing concentration of antidepressants in wastewater due to economic hardship and pressures correlated to the global pandemic is an environmental threat. Therefore, new and efficient methods for their removal need to be developed. Metal-organic frameworks (MOFs) are potent adsorbents for wastewater but there are limited reports on the adsorption potentials of an emerging class of dicarboxylate MOFs. Herein, we synthesised two aluminium-based dicarboxylate MOFs containing terephthalic (Al-MIL-53) and biphenyl (Al-Biphen) linkers for the adsorption of nortriptyline antidepressants from contaminated water. The MOFs were characterised by the TGA, SEM, PXRD, BET and FTIR and exhibited desirable surface properties for potent adsorption of nortriptyline. BET surface areas of 1024 m² g⁻¹ and 624 m² g⁻¹ were obtained for Al-Biphen and Al-MIL-53, respectively, which resulted in a maximum nortriptyline uptake capacity of 284.9 mg g⁻¹ and 246.3 mg g⁻¹. Optimum adsorption of nortriptyline was obtained at pH of 7.0, adsorbate concentration of 50 mg/L, contact time of 40 min and a temperature of 300 K. The Langmuir model was well correlated with the adsorption onto Al-Biphen, while both the Langmuir and Freundlich models were more suited for Al-MIL-53. The drug adsorption kinetics was well interpreted by the pseudo-second-order, Elovich, and intraparticle diffusion models. For both materials, the adsorption processes are exothermic and spontaneous with decreasing randomness. Moreover, less than 10.9% of the initial efficiency of the MOFs was lost after four cycles of reuse, which showed that the dicarboxylate MOFs are highly efficient, fast, and reusable for nortriptyline adsorption from aqueous phase.