Solanum nigrum is a traditional medicinal plant renowned as a cure for many diseases due to the presence of bioactive compounds. The Solanum nigrum complex refers to a group of more than 30 closely related but morphologically distinct taxa. Five indigenous taxa of this complex were investigated for their medicinal potential by using methanolic extracts. The efficacy of each plant was different for each of the seven bacteria studied. On comparing the MIC values, S. americanum was found to be most potent against Bacillus licheniformis (34 µg/mL), S. chenopodioides against Escherichia coli (78 µg/mL), S. nigrum against Bacillus licheniformis (49 µg/mL) and Escherichia coli (49 µg/mL), S. retroflexum against Escherichia coli (30 µg/mL), and S. villosum against Proteus mirabilis (45 µg/mL). The extracts were also subjected to six antioxidant assays. Moderate scavenging activity was observed by all plants in the DPPH free radical assay, but S. chenopodioides was the most effective. The total phenolic contents of the five plants were comparable, but the gallic acid equivalents of S. americanum and S. nigrum were the highest (26.58 mg/100 g GAE). The highest Trolox equivalent antioxidant capacity was observed for S. retroflexum, with the ABTS assay giving a TEAC value of 33.88 mM/100 g of dry weight. Metal-chelating activity against Fe²⁺ was observed to be highest for S. chenopodioides (70.37%). The FRAP value of S. nigrum was the highest (8.5 mM FeSO₄·7H₂O) among all taxa. The lipid peroxidation trend was very similar for all five samples. The results suggest the specified medicinal use of different members of the Solanum nigrum complex, which will also have significant nutritional value.

Air pollution, resulting from buffing dust waste produced by local leather tanning industry, has become a critical issue for the environment and public health. To promote a circular economy through resource recovery, this work developed a thermal insulation composite using buffing dust-laden tanning waste mixed with polystyrene and a blowing agent. To prepare the samples from leather tanning waste, different proportions of buffing dust (5–20% (w/w)) were blended with polystyrene in the presence of 3% (w/w) blowing agent. The composite material was processed in double-barreled with co-twin extruder to expose it to pressure and then heated at 200 °C. Different physico-chemical properties of composite samples were determined. The prepared composite materials had a good thermal conductivity (0.033–0.029 W/m-K), strong compression (5.21–6.25 ton), density (38–20 kg/m³), and water absorption (5–7.5%), as compared to conventional constructional insulation panels. The thermal conductivity of polystyrene was reduced to 10% after the addition of buffing dust (20% w/w). The presence of a blowing agent in the composite material enhanced its volume without compromising its physico-chemical properties. Thermo-gravimetric analysis showed that the thermal stability of the composite material ranged from 200–412 °C. FTIR analysis indicated that the composite had carbonyl and amino functional groups. The SEM images revealed the formation of voids with a decreasing homogeneity of the composite after the addition of the buffing dust waste. The EDX analysis revealed that the composite also had 62% of C and a tiny amount of Cr. This implies that the composite panels can be used for installation in buildings as thermal insulators in the construction sector. Overall, this work not only resolved the energy consumption problems during manufacturing, but it also brought positive impacts on the environment by recycling hazardous buffing dust and then reusing it as a thermal insulation material. Not only does this reduce the air pollution that results from the buffing dust waste, but this also promotes resource recovery in the framework of a circular economy.

In the present approach, a Cr₂O₃–TiO₂-modified, portable, and biomimetic nanosensor was designed to meet the requirement of a robust and colorimetric sensing of hydrogen peroxide. Cr₂O₃–TiO₂ nanocomposites prepared via the hydrothermal method were fabricated as a transducer surface on the filter paper using the sol–gel matrix. The color on the filter paper sensor changed from green to blue upon the addition of hydrogen peroxide in the presence of TMB. This change in the color intensity was linear with the concentration of H₂O₂. RGB software was used as a color analyzing model to evaluate the optical signals. This paper-based colorimetric platform provided us with an improved analytical figure of merit with a linear range of 0.005–100 μM with 0.003 μM limit of detection. The real sample analysis and excellent anti-interference potential results proved the good analytical performance of the proposed design, providing a more promising tool for colorimetric H₂O₂ detection. Introducing Cr₂O₃–TiO₂ nanocomposite-based paper sensors, being a novel method for optical and colorimetric detection, can pave the way for the development of other sensing devices for the detection of different analytes.

Active photocatalysts with an efficiency of 99% were prepared for the degradation of the industrial dye, methylene blue (MB), under visible light irradiation. These photocatalysts comprised Co/Ni-metal–organic frameworks (MOFs), to which bismuth oxyiodide (BiOI) was added as a filler to prepare Co/Ni-MOF@BiOI composites. The composites exhibited remarkable photocatalytic degradation of MB in aqueous solutions. The effects of various parameters, including the pH, reaction time, catalyst dose, and MB concentration, on the photocatalytic activity of the prepared catalysts were also evaluated. We believe that these composites are promising photocatalysts for the removal of MB from aqueous solutions under visible light.

The synthesis of MMT and poly(o-anisidine) (MMT/POA) clay nanocomposites was carried out by using the chemical oxidative polymerization of POA and MMT clay with POA, respectively. By maintaining the constant concentration of POA, different percentage loads of MMT clay were used to determine the effect of MMT clay on the properties of POA. The interaction between POA and MMT clay was investigated by FTIR spectroscopy, and, to reveal the complete compactness and homogeneous distribution of MMT clay in POA, were assessed by using scanning-electron-microscope (SEM) analysis. The UV–visible spectrum was studied for the optical and absorbance properties of MMT/POA ceramic nanocomposites. Furthermore, the horizontal burning test (HBT) demonstrated that clay nanofillers inhibit POA combustion.