Nanoscaled Bi₂O₃ particles coated on ZnO nanorods (ZNRs) have been fabricated by combining hydrothermal technique with a chemical precipitation method. X-ray diffraction, field emission-scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and UV–vis absorption and photoluminescence studies were adapted to characterize the structure, morphologies, and optical properties of the nanocomposites. The results indicated that small Bi₂O₃ nanoparticles were well distributed on the surfaces of ZNRs. And the Bi₂O₃–ZNR nanocomposites showed high charge separation efficiency and •OH generation ability as evidenced by photoluminescence spectra. Under irradiation of a 55-W compact fluorescent lamp, the Bi₂O₃–ZNR nanocomposites demonstrated photocatalytic activities higher than pure ZNRs in the degradation of two endocrine-disrupting chemicals, phenol and methylparaben, which might be attributed to the high separation efficiency of photogenerated electron–hole pairs based on the cooperative role of Bi₂O₃ loading on ZNRs. Moreover, the Bi₂O₃–ZNR nanocomposite could be easily recovered and reused due to their one-dimensional nanostructural property. All these characteristics brought enormous benefits of Bi₂O₃–ZNR nanocomposites to the practical application in indoor environmental remediation.

Hyperaccumulators contain tubular cellulose and heavy metals, which can be used as the sources of carbon and metals to synthesize nanomaterials. In this paper, carbon nanotubes (CNTs), Cu₀.₀₅Zn₀.₉₅O nanoparticles, and CNTs/Cu₀.₀₅Zn₀.₉₅O nanocomposites were synthesized using Brassica juncea L. plants, and the ultraviolet (UV)-light-driven photocatalytic degradations of bisphenol A (BPA) using them as photocatalysts were studied. It was found that the outer diameter of CNTs was around 50 nm and there were a few defects in the crystal lattice. The synthesized Cu₀.₀₅Zn₀.₉₅O nanocomposites had a diameter of around 40 nm. Cu₀.₀₅Zn₀.₉₅O nanocomposites have grown on the surface of the CNTs and the outer diameter of them was around 100 nm. The synthesized hybrid carbon nanotubes using B. juncea could enhance the efficiency of photocatalytic degradation on BPA. The complete equilibration time of adsorption/desorption of BPA onto the surface of CNTs, Cu₀.₀₅Zn₀.₉₅O nanoparticles, and CNTs/Cu₀.₀₅Zn₀.₉₅O nanocomposites was within 30, 20, and 30 min, and approximately 14.9, 8.7, and 17.4 % BPA was adsorbed by them, respectively. The combination of UV light irradiation (90 min) with CNTs, Cu₀.₀₅Zn₀.₉₅O nanoparticles, and CNTs/Cu₀.₀₅Zn₀.₉₅O nanocomposites could lead to 48.3, 75.7, and 92.6 % decomposition yields of BPA, respectively. These findings constitute a new insight for synthesizing nanocatalyst by reusing hyperaccumulators.

Functionalized magnetic core–zeolitic shell nanocomposites were prepared via hydrothermal and precipitation methods. The products were characterized by vibrating sample magnetometer, X-ray powder diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption–desorption isotherms, and transmission electron microscopy analysis. The growth of mordenite nanocrystals on the outer surface of silica-coated magnetic nanoparticles at the presence of organic templates was well approved. The removal performance and the selectivity of mixed metal ions (Pb²⁺ and Cd²⁺) in aqueous solution were investigated via the sorption process. The batch method was employed to study the sorption kinetic, sorption isotherms, and pH effect. The removal mechanism of metal ions was done by chem–phys sorption and ion exchange processes through the zeolitic channels and pores. The experimental data were well fitted by the appropriate kinetic models. The sorption rate and sorption capacity of metal ions could be significantly improved by optimizing the parameter values.

Nanocomposite hydrogels based on poly(methacrylamide-co-acrylic acid) and nano-sized montmorillonite were prepared by aqueous dispersion and in situ radical polymerization. Optimum sorption conditions were determined as a function of montmorillonite content, contact time, pH, and temperature. The equilibrium data of Cu(2+) and Ni(2+) conformed to the Freundlich and Langmuir isotherms in terms of relatively high regression values. The maximum monolayer adsorption capacity of the nanocomposite hydrogel (with 3 wt% montmorillonite content), as obtained from the Langmuir adsorption isotherm, was found to be 49.26 and 46.94 mg g(-1) for Cu(2+) and Ni(2+), respectively, at contact time = 60 min, pH = 6.8, adsorbent dose = 100 mg/ml, and temperature = 318 K. Kinetic studies of single system indicated that the pseudo-second order is the best fit with a high correlation coefficient (R (2) = 0.97-0.99). The result of five times sequential adsorption-desorption cycle shows a good degree of desorption and a high adsorption efficiency.