Advanced Materials Research Vols. 955-959

Abstract: This paper adopts a pot incubation test in greenhouse to study the enhancing applicability from earthworms (Pheretima sp.) live in the soil with PAHs.Pheretima (Pheretima sp.) had a certain level of tolerance towards PAHs polluted soils. Phenanthrene and pyrene were found to inhibit the growth of Pheretima to a certain extent. The inhibition rates were 7.09% ~ 25.19% and 6.79%~ 27.83% respectively. Furthermore, with increasing concentrations of PAHs in the soil, the inhibition effect on the growth of Pheretima became progressively stronger. In this experiment, the earthworms were found to have a certain role in promoting the degradation of phenanthrene and pyrene in the soil, but not to a significant extent, (n = 15, p> 0.05). Moreover, with the highering of the degradation ratio of pollutants, the rate of promotion of the earthworms on phenanthrene and pyrene degradation also decreased.

Abstract: Iron silicate, a stable and efficient catalyst prepared in the laboratory has been successfully used as a catalyst combined with ozonation in the degradation of p-Chloronitrobenzene (pCNB). The catalytic ozonation removal effectiveness of pCNB was investigated under various physicochemical conditions. Both the adsorption and the single ozonation were not effective for the degradation of pCNB, but the presence of iron silicate in ozonation process could substantially enhance the pCNB removal efficiency. The hydroxyl radical scavenger experiment confirmed that iron silicate catalytic ozonation followed a radical-type mechanism. The increasing of both the iron silicate dosage and the ozone dosage could enhance the removal effectiveness of pCNB. The iron silicate catalyst could be recycled easily without decreasing any ozone catalytic activity after four successive reuses. It is concluded that the iron silicate was an efficient green catalyst for pCNB degradation in drinking water.

Abstract: Five kinds of powder activatedcarbons were studied to investigate the removal of SO₂ from flue gasin a fixed bed reactor. The fractal dimension of activated carbon was determined by N₂ adsorption isothermat 77Kand SO₂ adsorptioncapacity was correlated with thefractal dimension. The results show thatthe activated carbons prepared from different precursors by differentactivation methods have different fractal dimension. Big differences in SO₂ adsorption capacity are found between fivekinds of activated carbons. SO₂ adsorption capacity increases with the fractaldimension increasing. The results indicate that the fractal dimension could be used as a indicator of SO₂removal capacity on powder activated carbon.

Abstract: Compared with a great deal of traditional desulphurization crafts, the catalytic reduction of SO₂ with CO to elemental sulfur is considered to be the best technology for the removal of SO₂ from flue gas. Adding rare earth oxide CeO2 with variable valences to La₂O₃ formed a mixture of rare earth oxides. By means of dipping CeO₂, La₂O₃ and their mixture, whose carriers are allγ-Al₂O₃, are used as the catalyst for the reduction of SO₂ by CO. The activation process of this catalyst without O₂ was investigated. The result shows that the rare earth oxide mixture composing of CeO₂ and La₂O₃, as the catalyst for the reduction of SO₂ by CO, can remove SO₂ mostly without O₂.

Abstract: The structure and arrangement of flue and deflector modules have significant influences on flue gas flow field and distribution of NH₃ concentration in a SCR reactor. Numerical calculations about distributions of velocity, NH₃ concentration and flow resistance in the deNOx reactor of a 1000MW power plant boiler with CFD have provided the optimal combination of layout scheme of guide plates. A1:15 experimental model of the reactor was constructed based on the principles of similarity theory, and cold model test was carried out with air substituting for flue gas, and CO for NH₃.The consequences of model test and numerical modeling were basically similar and met the design requirements. Moreover, deposition characteristics of the experimental model was studied with fly ash from coal-fired boiler, which demonstrated that deposition was not severe under both 50% and 100% boiler full load. The model experiments indicated that the optimum program could achieve purpose of the flow field optimization.

Abstract: With the development of modern industry, the environmental pollution problem caused by the non-ferrous metal smelting production process has become more and more serious. A lot of poisonous and harmful substances, which discharged in non-ferrous metal smelting process, enter soil via atmospheric deposition, waste residue infiltration and sewage irrigation, causing different levels of pollution of surrounding soil. In the paper, pollution sources, pollution situation and pollution harmfulness are analyzed in detail in non-ferrous metal smelting production process. Some pollution factors are concluded. Finally, some strategies and technology measures for controlling environmental pollution in non-ferrous metal smelting process are discussed.

Abstract: To form microbial nanoball, EM active calcium was immobilized on nano-silica carrier consisting of pond sediment, zeolite powder and nanosilica. Through real-time monitoring of pH, dissolved oxygen (DO), chemical oxygen demand (COD) and ammonia nitrogen (NH₄⁺-N) aquaculture wastewater, the purification effects of Microbial nanoSilica Ball on aquaculture wastewater under different mud-water ratio condition were studied. The results showed that the purification effect reached best in 3-6 days for all treatments and was better for mud-water ratio of 1:2.7. In this mud-water ratio, it was indicated that pH was maintained at 7-8.5 which was an optimum value for the aquaculture, the content of DO was increased by 82.16% compared with the initial value and the removal rate of COD and NH₄⁺-N was 57.80% and 54.60% respectively.

Abstract: This paper made the high absorbent resins poly 2-acrylamide-2-methyl propane sulfonic acid (PAMPS) by solution polymerization method, researched its adsorption properties to heavy metals Cu²⁺ and Zn²⁺ from landfill leachate, and studied the adsorbent dosage, pH and the adsorption times effect on adsorption effect. The results indicated: when the adsorbent dosage was 25 g/L, pH was 6.5 and adsorption time was 45 minitues, the removal rates of Cu²⁺ by PAMPS reached 89.5%. When the adsorbent dosage was 35 g/L, pH was 6.5 and adsorption time was 55 minitues, the removal rates of Zn²⁺ by PAMPS reached 96.8%.

Abstract: Due to the presence of complicated and considerable amounts of toxic compounds such as phenolic compounds, thiocyanate and ammonium, coal gasification wastewater (CGW) would cause a serious environmental problem. Conventional treatment of CGW includes a series of biological treatment (mostly anoxic-aerobic process and activated sludge process) after a physico-chemical pretreatment to reduce the concentrations of phenols and ammonium. Although quite effective, these processes are still not enough to meet the strict requirements of the National Discharge Standard of China. To find more efficient way to treat CGW, a serious of hybrid processes were reviewed in this study. Through this review we found that A²O combined with MBR (anaerobic-anoxic-aerobic membrane reactor) can effectively remove COD, total organic carbon, NH₄⁺ -N, total phenols and total nitrogen (TN).

Abstract: The distribution behaviors of iodide complex of Cd (II) in the propyl-alcohol ammonium sulfate aqueous biphasic extraction system was experimentally investigated in this work. Cd (II) was found to be extracted from the propyl-alcohol phase due to its ion pair formation as CdI₄^2-(PrOH²⁺)₂ in the presence of NH₄I and in HCL, and the associated extraction conditions were optimized. The experimental results indicated that cadmium can be efficiently extracted by the method, and an extraction rate of 99.1% for cadmium can be achieved under optimizing conditions.