Advanced Materials Research Vol. 908

Abstract: Biological nitrification and denitrification via nitrite pathway is technically feasible and economically favorable, especially when wastewater with high ammonium concentrations or low C/N ratios is treated. Therefore, it has attracted more and more attention. It is very important to maintain partial nitrification of ammonium to nitrite. In this paper, the factors that influence operation and efficiency of nitrification and denitrification via nitrite are discussed, including DO concentration, carbon source, aeration pattern, PH, temperature and high free ammonia. High ammonia concentration and temperature are prone to accomplish of short-cut nitrification and denitrification, but limit application in practice. Finally, the review discussed the future challenges for application of short-cut nitrification and denitrification.

Abstract: The sulfur retention mechanism of bio-briquette combustion is analyzed in the paper. The experimental research is carried out on the influence factors of biomass content, with inclusion of combustion temperature, Ca/S ratio, sulfur retention additives. The results indicate that when Ca/S ratio is equal to 2 and the combustion temperature is 850°C,the sulfur retention efficiency of low sulfur bio-briquette exceeds 60%.The rising trend becomes slow when Ca/S ratio is higher than 2.The sulfur retention effect will be reduced over 950°C. Using Fe₂O₃ as sulfur retention additive can significantly improve the sulfur retention capability of bio-briquette.

Abstract: Performance of simultaneous desulfurization and denitrification from N₂-NO-SO₂ simulated flue gas using sodium chlorite as the additive and urea as the reductant in a rotating packed bed was investigated. In RPB, various rotational speeds, the flow rates of SO₂, the flow rates of NO and the liquid flow rates were studied by means of the calculation of the removal efficiencies of SO₂ and NO. The experimental results showed that the removal efficiency of SO₂ was higher than 99.00% under various experimental conditions, while the removal efficiency of NO exhibited different results. A better simultaneous desulfurization and denitrification behavior could be obtained under the conditions of a SO₂-NO-N₂ simulated flue gas with the ratio of SO₂/NO/ N₂=6:4:8.33(v), a rotational speed of 460 rpm and an absorbent flow rate of 120 L/h.

Abstract: In this work, simultaneous absorption of SO₂ and NO from N₂-NO-SO₂ simulated flue gas using sodium chlorate as the additive and urea as the reductant was investigated experimentally in a rotating packed bed. In RPB, various rotational speeds, gas flow rates and liquid flow rates were studied by means of the removal efficiency of SO₂ and NO. The experimental results showed that the removal efficiency of SO₂ was higher than 99.00% under various experimental conditions and, at the same time, the removal efficiency of NO exhibited different results under various experimental conditions. The simultaneous NO removal efficiency of 82.45% and the SO₂ removal efficiency of 99.49% could be obtained under the N₂ flow rate of 0.5 m³/h, SO₂ flow rate of 6 mL/min, the NO flow rate of 4 mL/min, the rotational speed of 460 rpm and the absorbent flow rate of 40 L/h.

Abstract: Theoretical study aims to the way of obtain C₄H₆O⁺ fragments laser-induced by cyclicketone ion (C₇H₁₂O⁺) excited state, and gives out a result with proved and directed significance for the corresponding experiments. According to the analysis of C-C key vibration mode, mainly considering the C-H bond cleavage, H atom migration formed fragments, We can get the possible ways of C₄H₆O⁺ fragments are: 1C-7C, 4C-5C broken, formed C₄H₆O⁺ fragments, 2C-3C, 6C-5C broken, formed C₄H₆O⁺ fragments.

Abstract: This study combines the template method and sol-gel method, prepares TiO2 photocatalytic materials with the cotton, leaves and towel gourd as the template, and then makes degradation of phenol in ultraviolet light with the prepared TiO2 photocatalysts. The results show that all the photocatalyst prepared with three kinds of templates have high photocatalytic activity, among which, the catalytic performance of cotton is better, leaves secondly, and towel gourd’s relatively poor. With cotton as templates for the preparation of TiO2 under UV irradiation for 6h, the degradation rate was 80%, leaves as template for the preparation of TiO2 under UV irradiation for 6h, the degradation rate was 63%, and with towel gourd as template for the preparation of TiO2 under UV irradiation for 6h, the degradation rate was 52%.

Abstract: Treatment of inosine 5’-phosphate (IMP) with 2,2’-dithiodianiline/triphenylphosphine provided an efficient method for the synthesis of inosine 5′-phosphoropiperidate under mild conditions. Inosine 5’-triphosphate (ITP) and inosine 5′-diphosphate (IDP) were efficiently synthesized from inosine 5’-phosphoropiperidate via the activation P(V)—N bond by 4,5-dicyanoimidazole.

Abstract: A novel and efficient method for the preparation of acyclovir diphosphate and triphosphate has been developed. Phosphitylation, acid-catalyzed hydrolysis, and oxidative coupling with piperidine yielded acyclovir phosphoropiperidate benzyl ester intermediate in excellent yield. Acyclovir polyphosphates were synthesized in good yields by using the phosphoropiperidate/DCI system.

Abstract: As non-hydrolyzable analogs of stavudine 5’-triphosphate, β,γ-bridging oxygen-modified stavudine 5’-triphosphates (β,γ-CX₂-NTPs, X = H, F, and Cl) possess potential medicinal value in the treatment of viral infections and are of substantial interest to both synthetic and medicinal chemists. Three β,γ-bridging oxygen-modified stavudine 5’-triphosphates were synthesized from stavudine 5’-phosphoropiperidate with 4,5-dicyanoimidazole (DCI) as the activator.

Abstract: The diphosphate and triphosphate of an antiviral 2’,3’-dideoxynucleoside, d4T, were synthesized via a P(V)–N activation method. The key d4T phosphoropiperidate intermediate was obtained by a redox condensation method based on 2,2’-dithiodipyridine/triphenylphosphine system. The reaction of the phosphoropiperidate with phosphate and pyrophosphate in the presence of acidic 4,5-dicyanoimidazole activator afforded the desired d4T diphosphate and triphosphate in high isolated yields.