A novel type of adsorbent, TiO₂ impregnated pomegranate peels (PP@TiO₂) was successfully synthesized and its efficacy was investigated based on the removal of As(III) from water. The adsorbent was characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectrometer (EDS), X-ray Diffraction (XRD) analysis, and Fourier Transform Infrared (FTIR) Spectroscopy, to evaluate its morphology, elemental analysis, crystallinity, and functional groups, respectively. Batch experiments were conducted on PP@TiO₂ for As(III) adsorption to assess the adsorption isotherm, effect of pH, and adsorption kinetics. Characterization data suggested that TiO₂ was successfully impregnated on the biomass substrate. The equilibrium data better fitted to the Langmuir isotherm model having a maximum adsorption capacity of 76.92 mg/g and better distribution coefficients (K_D) in the order of ~10³ mL/g. The highest percentage of adsorption was found at neutral pH. The adsorption kinetics followed the pseudo-2nd-order model. X-ray Photoelectron Spectroscopy (XPS) of the adsorption product exhibited that arsenic was present as As(III) and partially oxidized to As(V). PP@TiO₂ can work effectively in the presence of coexisting anions and could be regenerated and reused. Overall, these findings suggested that the as-prepared PP@TiO₂ could provide a better and efficient alternative for the synergistic removal of As(III) from water.

Zinc oxide (ZnO) nanorods incorporated activated carbon (AC) composite photocatalyst was synthesized using a hydrothermal process. The AC was prepared from lapsi (Choerospondias axillaris) seed stone, an agricultural waste product, found in Nepal by the chemical activation method. An aqueous suspension of AC with ZnO precursor was subjected to the hydrothermal treatment at 140 °C for 2 h to decorate ZnO rods into the surface of AC. As-obtained ZnO nanorods decorated activated carbon (ZnO/AC) photocatalyst was characterized by various techniques, such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL) spectroscopy. Results showed that highly crystalline hexagonal ZnO nanorods were effectively grown on the surface of porous AC. The photocatalytic property of the as-prepared ZnO/AC composite was studied by degrading methylene blue (MB) dye under UV-light irradiation. The ZnO/AC composite showed better photocatalytic property than that of the pristine ZnO nanorods. The enhanced photocatalytic performance in the case of the ZnO/AC composite is attributed to the combined effects of ZnO nanorods and AC.

Lately, the upsurge in the liberation of synthetic dyes into the environment, primarily by the textile industries, is a threat to the natural habitat and existing ecosystem. Various methods such as adsorption and degradation with nanoparticles are currently being used to degrade those hazardous materials, but still, the yearning for novel methods continues. In this study, hydrothermal reactions were performed at 160°C to synthesize manganese dioxide nanostructures (MnNSs) under different incubation periods that facilitated the comparison of the size, morphology, and crystallinity of MnNSs. The study revealed the change in crystallinity over the incubation period; MnNSs prepared at 24 hrs were highly crystalline among others. Additionally, the size and morphology of MnNSs changed from the sea‐urchin or flower‐like structure, predominantly sheet/layer form, to nanorods as the reaction proceeded for 24 hrs. Characterization of MnNSs was followed by heterogeneous Fenton’s reaction, using α‐manganese dioxide nanostructures, for the degradation of methylene blue (MB). To further understand the catalytic activity of MnNSs, the synthesized nanostructures were subjected to degrade MB at varied time intervals, both with and without hydrogen peroxide (H₂O₂). Catalytically, MnNSs evinced good potential for degrading MB dye in the presence of H₂O₂; MnNSs prepared at 24 hrs degraded MB up to 73% within 110 minutes.

The characteristic NIR of copper sulfide nanocrystals (Cu_2−xS NCs) assemblies based on the LSPR can be controlled by exploiting monovalent lithium ions through electrochemical methods.