To overcome the limits of low adsorption capacity and the separation difficulty of solid from liquid phase for graphene oxide (GO), a novel nanocomposite graphene oxide-manganese oxide (GOMO) was facilely fabricated under ultrasonic radiation. The structures and micro-morphology of the products were characterized by fourier transform infrared (FT-IR) spectroscopy, raman shift spectroscopy, X-ray diffraction (XRD) pattern and scanning electron microscopy (SEM). The effect of solution pH, adsorbent dose, contact time, initial uranium concentration, ionic strength and temperature on uranium removal efficiency was studied by batch adsorption experiments. The product GOMO was used to examine the feasibility of the removal of high salt content in uranium-containing wastewater. The adsorption results were fitted using the Langmuir and Freundlich isotherm models. The kinetic parameters in the adsorption process were measured and fitted. Five adsorption/desorption cycles were performed using 3 M HNO 3 as the regenerant in order to evaluate the reuse of GOMO.
As an environmental semiconductor material, TiO2has important applications in the fields of environmental protection and water treatment. The preparation of P25 particles into nano-functional material films with a high specific surface area has always been a bottleneck limiting its large-scale application. In this paper, a one-step method of preparing TiO2nanocomposites by doping carbon nanotube (CNT) and carbon quantum dots (CQD) with tetrabutyltitanate and P25 TiO2under ultrasonic radiation is proposed to synthesize a novel antifouling material, which both eliminates the bacterium of Escherichia coli and shows good photoelectric properties, indicating a great value for the industrial promotion of TiO2/CNT. This mesoporous composite exhibits a high specific surface area of 78.07 M2/g (BET) and a tested pore width range within 10–120 nm. The surface morphology of this composite is characterized by TEM and the microstructure is characterized through XRD. This preparation method can fabricate P25 particles into a nano-functional material film with a high specific surface area at a very low cost.Keywords:TiO2;carbon quantum dots;one-step synthesis;ultrasonic radiation;carbon nanotube;mesoporous nanocomposites
Green synthesis of silver nanoparticles (AgNPs) has been extensively studied by using a variety of plant extracts for applications in biomedical sciences and engineering. However, there are no reports on the synthesis of AgNPs by utilizing the berry extract of Sea Buckthorn, which is a traditional Chinese medicine and exhibits a wide spectrum of antioxidant, anti-inflammatory and anticancer activities. In this paper, we report an easy and eco-friendly technique for the preparation of AgNPs using the Sea Buckthorn berry extract under ultrasonic radiation at ambient temperature and the evaluation of both biosynthesis parameters and biological activities. The UV-visible spectrum and dynamic light scattering (DLS) analysis showed that the size of AgNPs was sensitive to the biosynthesis parameters, such as the pH of the extract, material proportion and reaction time, offering a size-controlled synthetic method for AgNPs. The X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and DLS studies showed that the AgNPs (pH 10.0; material proportion 1 : 1; 4 h) had a face-centered cubic (fcc) structure and spherical shape with an average particle size of 27.3 ± 0.2 nm covered by anions, and existed in a monodispersed form with a polydispersity index (PDI) of 0.213. The biosynthesized AgNPs showed potent anticancer activity against human colorectal cancer (HCT116 and SW620), hepatoma cancer (HepG2), breast cancer (MCF-7) and cervical cancer (HeLa) cell lines as well as strong antioxidant activity. The IC50 values for these five cell lines were 8.77, 4.61, 14.59, 16.05 and 27.98 μg mL−1, respectively. However, the biosynthesized AgNPs revealed poor inhibition activities for the growth of E. coli and S. aureus. These results confirmed that the Sea Buckthorn could be a low-cost, nontoxic and eco-friendly natural resource for the synthesis of AgNPs, which might be useful for the development of new alternative antioxidant and anticancer agents in biomedicine.
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