[Ammonium Adsorption Characteristics in Aqueous Solution by Dairy Manure Biochar].

The adsorption characteristics of ammonium from aqueous solution onto biochar derived from dairy manure were investigated as a function of parameters such as solution pH, particle size, adsorbent dosage, temperature and competitive cations. The results indicated that the effects of other cations on the adsorption of ammonium followed the order of preference Na > Ca2+ at identical mass concentrations. It was observed that pH played an important role in the ammonium adsorption and the optimal pH values ranged between 5 and 8. The kinetic data fitted the pseudo-second-order model (R2 = 0.967 3) but showed very poor fits for the pseudo-first-order model (R2 = 0.765 9) and the Elovich model (R2 = 0.724 9). The results from the Intra-particle model also showed that there were two separate stages in sorption process, which were external diffusion and the diffusion of inter-particle. Adsorption isotherms for dairy manure biochar were fitted the Freundlich model (R2 = 0.976 2) more effectively than other models. Thermodynamics parameters such as free energy (ΔGθ), enthalpy (ΔHθ), and entropy (ΔSθ) were also determined, which indicated that the adsorption was a spontaneous and endothermic process.

[Sorption behavior of Triton X-100 on loess and affecting factors].

Batch experiments involving soil-aqueous systems were conducted to determine sorption of Triton X-100 onto natural loess as a function of equilibrium time, Triton X-100 concentration, ionic strength, and pH value. The results showed that the equilibration time for sorption of Triton X-100 onto loess was about 30 min. The sorption kinetics of Triton X-100 fitted well to the pseudo-first-order kinetic model and the corresponding parameters Q(e), k1, and r2 were 3.041 mg x g(-1), 0.102 min(-1), and 0.9934, respectively. Sorption isotherm was found to be distinctly nonlinear. The Sips model provided the best fitting to the experimental data among the four isothermal models tested. Q(max) and r2 of Sips model were 3.202 mg x g(-1) and 0.998 7, respectively. It was found that the ionic strength and the pH of the solution had a significant influence on the sorption of Triton X-100 onto loess. The amount of Triton X-100 sorbed onto the loess increased significantly with increasing concentration of NaCl. Sorption of Triton X-100 onto loess was influenced greatly by pH, the amount of Triton X-100 sorbed decreased as the pH increased.

[Remediation of Cu/phenanthrene and combined contaminated loess soil by chemical-enhanced washing].

The chemical-enhanced washing of Cu2+ or/and phenanthrene (PHE) single or combined contaminated loess soil in Gansu Province was investigated with disodium ethylene diamine tetraacetate (EDTA) or/and sodium dodecyl sulfate (SDS) by the batch equilibrium experiments. The experimental results showed that EDTA or/and SDS could remove efficiently Cu2+ and/or PHE in single-contaminated or combined contaminated loess soils. The Cu2+ removal was significantly promoted by coexisting PHE with low concentration of EDTA (EDTA < 0.1 mol/L), however, the removal was slightly hindered with high concentration of EDTA (EDTA > 0.1 mol/L). As for the PHE removal by EDTA, it was founded that coexisting Cu2+ could enhance the PHE removal in the investigated ranges of the concentrations of EDTA. When concentration of EDTA was 0.01 mol/L, the removal of combined PHE was 20.94% higher than that of single PHE. The experimental results of the removal of contaminations by SDS showed that coexisting Cu2+ could suppress slightly the removal of PHE at a concentration of less than 4 000 mg/L SDS, but could assist the removal of PHE in 5 000 mg/L or higher SDS concentration. On the contrary, the influence of coexisting PHE for the removal of Cu2+ by SDS was that it facilitated Cu2+ extraction by low concentrations of SDS, however, it inhibited the removal of Cu2+ at high concentrations of SDS. The removal efficiencies of PHE and Cu2+ were improved greatly as using combined EDTA-SDS. Beside, there are some differences in the removal efficiency of the oth contaminants with the different sequence of EDTA and SDS added in the washing solution. In EDTA washing followed by SDS, SDS washing followed by EDTA and mixture of SDS-EDTA washing concurrently, the removal of Cu2+ is 91.40%, 95.10% and 96.50%, respectively, which is 28.46%, 32.16%, 33.56% higher than that of combined, 62.94%, by single EDTA. For PHE, the removal is 68.30%, 85.40%, 84.95%, respectively, which is 16.14%, 33.24%, 32. 79% higher than that of combined PHE, 52.16%, by single SDS. Thus, SDS washing followed by EDTA or mixture of SDS-EDTA washing concurrently is considered as the optimal washing sequence for PHE and Cu2+ removal.

2,2'-[1,1'-(Propane-1,3-diyldioxy-dinitrilo)diethyl-idyne]diphenol.

The title compound, C(19)H(22)N(2)O(4), was synthesized by the reaction of 2'-hydroxy-acetophenone with 1,3-bis-(amino-oxy)propane in ethanol. Intra-molecular O-H⋯N and weak C-H⋯O hydrogen bonds stabilize the three-dimensional structure. A twofold rotation axis passes through the molecule.

6,6'-Dimeth-oxy-2,2'-[(hexane-1,6-diyldi-oxy)bis-(nitrilo-methyl-idyne)]diphenol.

In the title compound, C(22)H(28)N(2)O(6), strong intra-molecular O-H⋯N hydrogen bonds and weak inter-molecular C-H⋯O hydrogen bonds stabilize the three-dimensional supra-molecular structure.