Papers by Keyword: Phosphorus

Abstract: Phytoremediation is the most commonly selected option for decontaminating the nutrients in eutrophic water bodies in recent years. In the present study, the effects of pH and illumination time on removing nitrogen and phosphorus by purple-root water hyacinth were investigated. The results indicate that there would be a better removal rates of nitrogen and phosphorus under the condition of pH=6~7 and t=8~10 h. Both acid and alkali conditions would slow down the purification effects and increasing illumination time can not improve the removal rate remarkablely. Therefore, it provides an important theoretical foundation for the efficient use of purple-root water hyacinth to restore eutrophic water bodies.

Abstract: The Equilibrium Phosphorus Concentration (EPC₀) of Hohhot dust (HD) of Inner mongolia was measured to examine whether the HD acted as sources or sinks of soluble reactive phosphorus (SRP) to the Yellow River water column. The modified Langmuir isotherm equation was modified to describe phosphorus (P) adsorption on the HD in Yellow River water. The EPC₀ was higher than P concentration in the overlying water, which indicates that the HD acted as sources of phosphate. In addition, solid concentration (C_s) effect existed obviously in P adsorption experiment and the hysteresis got bigger as C_s increased.

Abstract: Based on the main factor of hydraulic loading, removal of nitrogen and phosphorus and effluent quality of rural domestic wastewater were studied in subsurface constructed wetlands-ponds system in Jiangxi Province. The results showed that there had good processing results on nitrogen and phosphorusremoval by subsurface constructed wetlands-ponds system,especially on removal of phosphorus.In the combined system removal influence of nitrogen and phosphorus were affected by hydraulic loading,it was influenced more significantly for nitrogen removal and had less influence on removal effect of phosphorus relatively.When the hydraulic loading was 72 m³·m^-2·d^-1, removal rate of TNNH₃-NTP were 75.3%76.08%86.77% respectively,which was very good for the combined system;removal rate of TNNH₃-NTP were 42.67%33.62%61.72% in the subsurface constructed wetlands; removal rate of TNNH₃-NTP were 32.63%42.46%25.05% in the ponds.While hydraulic loading was lower,the subsurface constructed wetlands was the control factor for the combined system.With the increasing of hydraulic loading,the ponds was the control factor gradually. In the combined system, effluent quality of TN was superior to the first class B criteria specified in GB 18918-2002(15mg·L^-1),effluent quality of NH₃-N was superior to the first class B criteria (8mg·L^-1), effluent quality of TP was superior to the case-Vwaters of surface water quality (GB3838-2002) standard (0.4 mg·L^-1) .Research results could be the basis of combined system in Jiangxi Province.

Abstract: This paper discusses the temporal and spatial distribution of nitrogen, phosphorus in the soil with typical crops planted on in Headwater Region of Liao He. The purpose is to provide theoretical basis for the prediction of the non-point source pollution and protection of the environment in Headwater Region of Liao He. The results show that the content of the substance which can be absorbed by plants was higher in the surface soil than that in the bottom soil. The nitrate nitrogen content in soil was lower in autumn than that in spring except normal planting surface soil. And the ammonia nitrogen content was also a little lower in autumn than that in spring except normal planting surface soil and blank control land 1. In autumn, the hydrolyzable nitrogen content in the surface soil was decreased slightly and it was nearly unchanged in the bottom soil. The total nitrogen content was higher in autumn. The content of available phosphorus was a little higher or nearly unchanged in autumn than that in spring, the content of total phosphorus changed irregularly.

Abstract: The kinetic models of COD removal and phosphorus release in anaerobic zone, and phosphorus uptake, nitrification, denitrification and COD removal in circulating corridors were established in this work, in order to provide the guidance on design and running of the modified oxidation ditch. At the same time, the coefficients of reaction rates were calculated. Using the kinetic models already been established and the coefficients already been calculated to simulate the experimental results, the results showed that the models can well simulate the removal effect of pollutants in the modified oxidation ditch.

Abstract: adsorption is a good method to remove phosphorus. In the experiment, lithium silica fume is used as the adsorption material, adsorption isotherms ,kinetics and dosage effects were examined. It shows that the adsorption kinetics data are consistent with the pseudo-second-order equation and the adsorption is easy to happen. Freundlich isotherm equation is fit for description of the adsorption. The maximum adsorption capacities on lithium silica fume is 1.166 mg/g. When dosage get to 12 g/l and the concentration of phosphorus solution is 2 mg/l, the removal rate reach to 95% at 308k.

Abstract: A novel polymeric phosphate flame retardant (PFR-P) was synthesized from 1-oxo-4-hydroxymethyl-2,6,7-trioxa-1-phosphbicyclo [2.2.octane (pentaerythritol phosphate, PEPA), POCl₃ and bisphenol S. Phosphorus was bonded both in the main chain and in the pendant group of flame-retardant polymer molecule, reached a content of 13.1%. And sulfur content was 6.75%. The thermal stability was investigated by TGA, and the results showed that the initiative decomposition temperature was 334°C with 41.1% charring residue at 500°C under air. The high phosphorus and sulfur content contributes an excellent flame retardancy to PC/ABS without a considerable decrease of mechanical properties. It is a potential flame retardant for other polymer systems.

Abstract: The study aimed at phosphorus and nitrogen removal by honeycomb cinder modified with Zinc chloride (ZnCl₂). By bench-scale batch experiments, honeycomb cinders with different modification time and ZnCl₂ dosage were modified and its adsorption capacities were evaluated by methylence blue as the adsorbate. Under the optimal modification conditions, large amount modified honeycomb cinders were prepared to remove the phosphorus and nitrogen from domestic sewage, which different operating conditions of honeycomb cinders dosage, and contact time were considered. The results show that removal efficiencies of total phosphate (TP), orthophosphate (PO₄³-P), total nitrogen (TN) and ammonia nitrogen (NH⁴⁺-N) could reach 89.9%, 96.7%, 18.9% and 23.3% under the optimal conditions, respectively. Modified honeycomb cinders might be an effective and low cost adsorbent for phosphorus removal.

Abstract: Iron oxides play an important role in controlling P activity and availability in environmental systems. Two iron oxides (goethite and ferrihydrite) were synthesized characterized by X-ray diffraction, transmission electron microscopy and N₂ adsorption method. To investigate the effect of silicon on phosphorus adsorption of them, batch equilibration method was used. Attempts were made to explore the mechanisms involved by eliminating effects of pH and accompany ions. Results reveal that the ability of two kinds of iron oxides adsorbed phosphorus were as follows: ferrihydrite > goethite. Compared with the control, silicon inhibited the adsorption of phosphorus on two iron oxides, and this effect increased with the increasing of silicon content. Langmuir, Freundlich and Temkin equations could be used to describe the adsorption characteristics of phosphorus on iron oxides well, but the Langmuir model was optimal. With silicon addition, the adsorption equilibrium constants (K) decreased of the phosphorus absorbed on iron oxide, the free energy(ΔG)dropping degree increased, the maximum adsorption capacity(X_m)and maximum buffering capacity (MBC) reduced.

Abstract: The black soil was taken as the research object, and the phosphorus sorption-desorption kinetics characteristics of different components of colloidal dispersion complex in black soil were studied. Results showed that the maximum phosphorus adsorption amount by different components of the colloidal dispersion complex decreased in the order of G₀ < G₁2, and the adsorption amount would be stable as the time increase, while the desorption amount was in the order of G₁>G₀>G₂. The Elovich equation was the optimal model to describe phosphorus adsorption by different components of colloidal dispersion complex, which fitted better than the Two-constant equation.