[Substructure Characteristics of Combined Acid-Base Modified Sepiolite and Its Adsorption for Cd(â ¡)].

To enhance the adsorption capacity of sepiolite (Sep) on Cd2+ in solution, an acid-base Sep (ABsep) was obtained using the method of combined acid-base modification. The structural properties of Sep and ABsep were analyzed by adsorption-desorption isotherms of N2, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray powder diffraction (XRD). Static adsorption experiments were carried out to evaluate the effects of time, mass ratio of ABsep/Cd2+, temperature, adsorbent dose, pH, and co-existing ions on the adsorption of Cd2+ by ABsep. The results showed that the pore structure of the ABsep was more developed than that of Sep. In comparison to Sep, the specific surface area, average pore diameter, and pore volume of ABsep increased by 66.1%, 15.7%, and 34.8%, respectively, and the exchangeable ion contents also increased. The main components of the ABsep were SiO2 and Mg(OH)2. The adsorption process of Cd2+ by Sep and ABsep could be well fitted with a pseudo-second-order kinetic equation and Langmuir isotherm, and both were spontaneous endothermic reactions, which were mainly chemical adsorption along with physical adsorption. The best mass ratio of ABsep:Cd2+ was 3:1, and the maximum saturated adsorption capacity fitted by the Sips model of the ABsep on Cd2+ at 298 K was 142.43 mg·g-1, which was 3.55 times that of Sep. As the adsorbent dose increased, the adsorption amounts of Cd2+ first increased and then decreased, with the optimum dose being 0.3 g·L-1. The amount of Cd2+ adsorption by the ABsep increased with the initial pH of the solution, whereby the best pH was 7. We also found that the presence of K+, Na+, Mg2+, and Ca2+ at different concentrations could inhibit the adsorption of Cd2+, whereby the inhibition of Mg2+ was the highest.

[Effect of Different Passivating Agents on the Stabilization of Heavy Metals in Chicken Manure Compost and Its Maturity Evaluating Indexes].

We explore the effects of different passivating agents on livestock manure treatment by using chicken manure and straw as raw materials and thermophilic rapid fermentation. We investigate the effects of sepiolite (SE), calcium magnesium phosphate fertilizer (NP), biochar (BI), compounds of sepiolite plus calcium magnesium phosphate fertilizer (S+N), sepiolite plus biochar (S+B), calcium magnesium phosphate fertilizer plus biochar (N+B), and sepiolite plus calcium magnesium phosphate fertilizer and biochar (SNB) on the physical and chemical characteristics, heavy metal fraction and distribution, and organic matter content in chicken manure compost. The results showed that the addition of different passivating agents significantly increased the pH in chicken manure organic fertilizer (P<0.05). The seed germination rate was increased after applying of passivation agents, being>80%, and the germination inhibition rate decreased accordingly, whereas the values of electric conductivity (EC) and organic carbon were inhibited. The total nitrogen content and carbon/nitrogen ratio (C/N) were lower than of those before composting, and all of the indicators reached the standard of organic fertilizer maturity. However, differences among the groups after composting were that the pH increase in the compounding treatment was comparatively higher, and that the EC decreased significantly under the treatment of the single sepiolite and calcium magnesium phosphate, whereas the total nitrogen content and C/N ratio of organic carbon were not significantly different in each group. Although the total amount of heavy metals in our organic chicken manure fertilizer increased due to a concentration effect, the proportion of exchangeable heavy metals in the fertilizer decreased, and while the ratio of the residual heavy metals increased. The passivation effect on heavy metals under combined treatments of different materials was better than that of a single agent, and the SNB treatment had the best effect on the passivation of Ni, Zn, As, and Pb. After composting treatment, the concentrations of humic substances (HS) and humic acid (HA) increased significantly (P<0.05), and the highest concentrations increased by 19.8% and 78.9%, respectively. The amount of fulvic acid (FA) decreased by 4.47%-20.11% compared with the initial conditions. Infrared spectroscopy analysis showed that the small molecular substances of polysaccharides increased after composting. In summary, the addition of a passivation agent can promote the heavy metal passivation in chicken manure organic fertilizers to potentially render the compost as harmless.

Investigation of low-resistivity from hydrogenated lightly B-doped diamond by ion implantation.

We have implanted boron (B) ions (dosage: 5×1014 cm-2) into diamond and then hydrogenated the sample by implantating hydrogen ions at room temperature. A p-type diamond material with a low resistivity of 7.37 mΩ cm has been obtained in our experiment, which suggests that the hydrogenation of B-doped diamond results in a low-resistivity p-type material. Interestingly, inverse annealing, in which carrier concentration decreased with increasing annealing temperature, was observed at annealing temperatures above 600 °C. In addition, the formation mechanism of a low-resistivity material has been studied by density functional theory calculation using a plane wave method.