Bacterial valorization of agricultural-waste into a nano-sized cellulosic matrix for mitigating emerging pharmaceutical pollutants: An eco-benign approach.

For Bacterial Nanocellulose (BNC) production, standard methods are well-established, but there is a pressing need to explore cost-effective alternatives for BNC commercialization. This study investigates the feasibility of using syrup prepared from maize stalk as a valuable nutrient and sustainable carbon source for BNC production. Our study achieved a remarkable BNC production yield of 19.457 g L-1 by utilizing Komagataeibacter saccharivorans NUWB1 in combination with components from the Hestrin-Schramm (HS) medium. Physicochemical properties revealed that the obtained BNC exhibited a crystallinity index of 60.5 %, tensile strength of 43.5 MPa along with enhanced thermostability reaching up to 360 °C. N2 adsorption-desorption isotherm of the BNC displayed characteristics of type IV, indicating the presence of a mesoporous structure. The produced BNC underwent thorough investigation, focusing on its efficacy in addressing environmental concerns, particularly in removing emerging pharmaceutical pollutants like Metformin and Paracetamol. Remarkably, the BNC exhibited strong adsorption capabilities, aligning with the Langmuir isotherm and pseudo-second-order model. Thermodynamic analysis confirmed a spontaneous and endothermic adsorption process. Furthermore, the BNC showed potential for regeneration, enabling up to five recycling cycles. Cytotoxicity and oxidative stress assays validated the biocompatibility of BNC. Lastly, the BNC films displayed an impressive 88.73 % biodegradation within 21 days.

Investigation on surface sulfate attack of nanoparticle-modified fly ash concrete.

Sulfate attack on concrete structures is a major durability concern wherein concrete interacts with marine water, swamp water, groundwater, sewage water, freshwater, etc. In this study, the supplementary cementitious materials such as fly ash (FA) and nanoparticles are together incorporated into conventional concrete aiming to enhance the resistance of concrete against the penetration of sulfates. The present work is focused to understand the degradation in FA concrete modified with nanoparticles by surface sulfate attack. Concrete mix such as FA and FA modified with 2 wt% nano-TiO2 (FAT), nano-CaCO3 (FAC), and 1:1 ratio of nano-TiO2 to nano-CaCO3 (FATC) was fabricated. The specimens were exposed in 3% of ammonium and sodium sulfate for 90 days. The deterioration effects and changes in microstructural properties in all the specimens were comparatively studied. Results showed FAT, FAC, and FATC concrete have been deteriorated in ammonium and sodium sulfate solution compared with FA concrete. Partial replacement of cement with fly ash decreases the quantity of freely available reactive aluminates. Consumption of free lime by the fly ash prevents to react with sulfate. The enhanced properties of fly ash concrete against sulfate attack could be achieved with less C3A content thus reducing the available Ca(OH)2 and reducing the possibility of development of deleterious ettringite and gypsum.