The majority of nanoparticles tend to agglomerate in bacterial growth media. Thus, nanoparticle-specific characteristics can get lost. To investigate the influence of nanoparticles on bacteria, these particles should ...The majority of nanoparticles tend to agglomerate in bacterial growth media. Thus, nanoparticle-specific characteristics can get lost. To investigate the influence of nanoparticles on bacteria, these particles should remain in their nanoparticulate state. The present study demonstrates the stabilization of commercially available zinc oxide (ZnO) with sodiumhexametaphosphate (SHMP) in bacterial growth medium (LB) to avoid agglomeration of these particles after the addition to LB. This established method is appropriate to stabilize ZnO agglomerates as small as 43 nm. The method of fractionated centrifugation was used to obtain stable agglomerates (also stable in the presence of bacteria) with different mean diameters. The SHMP-stabilized ZnO inhibits the growth of Pseudomonas putida with increasing concentration (up to 500 mg/L) and decreasing agglomerate size (43 - 450 nm).展开更多
The present study focuses on the adsorption of a polyelectrolyte, the component of which is a polymer of maleic anhydride sodium salt, on the surface of nanometric zinc oxide particles and the colloidal stability of a...The present study focuses on the adsorption of a polyelectrolyte, the component of which is a polymer of maleic anhydride sodium salt, on the surface of nanometric zinc oxide particles and the colloidal stability of aqueous dispersions. FTIR spectroscopic data provided evidence in support of hydrogen bonding and chemical interaction in the case of the polyelectrolyte-ZnO system. The adsorption iso-therms showed the influences of polyelectrolyte concentra-tion, pH and ionic strength on the adsorption. With the in-crease of pH the saturated adsorbed amount decreased, while the thickness of adsorption layer increased. The saturated adsorbed amount increased with increasing salt concentra-tion, and decreased with further increasing salt concentra-tion. It should be noted that in the presence of a CaCl2 solu-tion the adsorbed amount and the adsorption layer thickness were greater than those in the NaCl solution of the same concentration. The change of the absorbance of zinc oxide dispersions showed that the absorbance decreased slowly at high pH. There was a maximum point for the absorbance of the zinc oxide dispersions in the presence of various polye-lectrolyte concentrations. The change of dispersion stability resulted from the change of macromolecular chains confor-mation at the interface.展开更多
Nowadays, nano mineral modified biochars show a promising adsorption capacity for pollutants removals by combining the advantages of porous structure of biochar and unique property of nano minerals. In this work, nano...Nowadays, nano mineral modified biochars show a promising adsorption capacity for pollutants removals by combining the advantages of porous structure of biochar and unique property of nano minerals. In this work, nano-zinc oxide doped scrap tire derived activated carbon (nZnO-STAC) was synthesized by wetness impregnation method. Equilibrium data were analyzed using Langmuir and Freundlich isotherm models while the kinetics of the process were examined using Lagergren Pseudo-first and second order, intraparticle diffusion and Elovich kinetic models. Characterization of the activated carbon by Powder X-ray Diffraction (PXRD). The surface groups present on the activated carbon surface were determined using the Fourier Transform Infra-Red Spectroscopy (FTIR) analysis. Optimization studies were carried out to determine the effects of pH, initial metal concentration, adsorbent dosage, contact time and adsorbent particle size on the Cr (VI) removal efficiency. The results showed optimum Cr (VI) removal at pH 3, 10 mg/L concentration, 120 minutes of contact using 1000 - 1400 μm adsorbent particle size at a dosage of 2.5 g/L. The adsorbent structure was found to be predominantly amorphous. The chromium removal efficiency of the adsorbent was around 81.6%. Of the tested kinetic models, the pseudo-second order model exhibited the best fit with the experimental data with an R<sup>2</sup> value of 0.9744. This study clearly demonstrates the feasibility of using the nano-ZnO doped scrap tyre derived activated carbon adsorbent for the remediation of chromium (VI) polluted industrial wastewaters.展开更多
Highly conductive and dispersible Al-doped ZnO(AZO) nanoparticles(NPs) have been successfully prepared by ligand-free colloidal synthesis at low temperature and stabilization by surfactant-aid including ethanolamine(E...Highly conductive and dispersible Al-doped ZnO(AZO) nanoparticles(NPs) have been successfully prepared by ligand-free colloidal synthesis at low temperature and stabilization by surfactant-aid including ethanolamine(EA), ethylenediamine(EDA),diethylenetriamine(DETA) and triethylenetetramine(TETA). Due to the strong intermolecular hydrogen-bonding interactions between AZO NPs and the amino groups from surfactants, the inevitable aggregation was suppressed and the surface defect sites were passivated obviously. The existence of electron transfer from the nitrogen of the amino groups to the zinc of AZO,led to a dramatic increase in electrical conductivity. A homogeneous current intensity value up to ~2200 pA for AZO tread by DETA was characterized by conductive atomic force microscopy(C-AFM), which was more superior than that of the reported sol-gel synthesized AZO with the assistance of EA surfactant(refer to 170.7 pA). Furthermore, non-fullerenes solar cells based on PBDB-T:ITIC with AZO-DETA(80 nm) yielded a best device efficiency of 10.7% and kept up prominent PCE exceeding 10%even with more thicker interlayer(95 nm).展开更多
文摘The majority of nanoparticles tend to agglomerate in bacterial growth media. Thus, nanoparticle-specific characteristics can get lost. To investigate the influence of nanoparticles on bacteria, these particles should remain in their nanoparticulate state. The present study demonstrates the stabilization of commercially available zinc oxide (ZnO) with sodiumhexametaphosphate (SHMP) in bacterial growth medium (LB) to avoid agglomeration of these particles after the addition to LB. This established method is appropriate to stabilize ZnO agglomerates as small as 43 nm. The method of fractionated centrifugation was used to obtain stable agglomerates (also stable in the presence of bacteria) with different mean diameters. The SHMP-stabilized ZnO inhibits the growth of Pseudomonas putida with increasing concentration (up to 500 mg/L) and decreasing agglomerate size (43 - 450 nm).
文摘The present study focuses on the adsorption of a polyelectrolyte, the component of which is a polymer of maleic anhydride sodium salt, on the surface of nanometric zinc oxide particles and the colloidal stability of aqueous dispersions. FTIR spectroscopic data provided evidence in support of hydrogen bonding and chemical interaction in the case of the polyelectrolyte-ZnO system. The adsorption iso-therms showed the influences of polyelectrolyte concentra-tion, pH and ionic strength on the adsorption. With the in-crease of pH the saturated adsorbed amount decreased, while the thickness of adsorption layer increased. The saturated adsorbed amount increased with increasing salt concentra-tion, and decreased with further increasing salt concentra-tion. It should be noted that in the presence of a CaCl2 solu-tion the adsorbed amount and the adsorption layer thickness were greater than those in the NaCl solution of the same concentration. The change of the absorbance of zinc oxide dispersions showed that the absorbance decreased slowly at high pH. There was a maximum point for the absorbance of the zinc oxide dispersions in the presence of various polye-lectrolyte concentrations. The change of dispersion stability resulted from the change of macromolecular chains confor-mation at the interface.
文摘Nowadays, nano mineral modified biochars show a promising adsorption capacity for pollutants removals by combining the advantages of porous structure of biochar and unique property of nano minerals. In this work, nano-zinc oxide doped scrap tire derived activated carbon (nZnO-STAC) was synthesized by wetness impregnation method. Equilibrium data were analyzed using Langmuir and Freundlich isotherm models while the kinetics of the process were examined using Lagergren Pseudo-first and second order, intraparticle diffusion and Elovich kinetic models. Characterization of the activated carbon by Powder X-ray Diffraction (PXRD). The surface groups present on the activated carbon surface were determined using the Fourier Transform Infra-Red Spectroscopy (FTIR) analysis. Optimization studies were carried out to determine the effects of pH, initial metal concentration, adsorbent dosage, contact time and adsorbent particle size on the Cr (VI) removal efficiency. The results showed optimum Cr (VI) removal at pH 3, 10 mg/L concentration, 120 minutes of contact using 1000 - 1400 μm adsorbent particle size at a dosage of 2.5 g/L. The adsorbent structure was found to be predominantly amorphous. The chromium removal efficiency of the adsorbent was around 81.6%. Of the tested kinetic models, the pseudo-second order model exhibited the best fit with the experimental data with an R<sup>2</sup> value of 0.9744. This study clearly demonstrates the feasibility of using the nano-ZnO doped scrap tyre derived activated carbon adsorbent for the remediation of chromium (VI) polluted industrial wastewaters.
基金supported by the National Natural Science Foundation of China (51603099, 51672121)the National Science Fund for Distinguished Young Scholars (51425304)
文摘Highly conductive and dispersible Al-doped ZnO(AZO) nanoparticles(NPs) have been successfully prepared by ligand-free colloidal synthesis at low temperature and stabilization by surfactant-aid including ethanolamine(EA), ethylenediamine(EDA),diethylenetriamine(DETA) and triethylenetetramine(TETA). Due to the strong intermolecular hydrogen-bonding interactions between AZO NPs and the amino groups from surfactants, the inevitable aggregation was suppressed and the surface defect sites were passivated obviously. The existence of electron transfer from the nitrogen of the amino groups to the zinc of AZO,led to a dramatic increase in electrical conductivity. A homogeneous current intensity value up to ~2200 pA for AZO tread by DETA was characterized by conductive atomic force microscopy(C-AFM), which was more superior than that of the reported sol-gel synthesized AZO with the assistance of EA surfactant(refer to 170.7 pA). Furthermore, non-fullerenes solar cells based on PBDB-T:ITIC with AZO-DETA(80 nm) yielded a best device efficiency of 10.7% and kept up prominent PCE exceeding 10%even with more thicker interlayer(95 nm).
