Bing Liu,Xiaochen Xu,Yuan Xue,Lifen Liu,Fenglin Yang
An integrated method of simultaneous desulfurization and denitrification from flue gas by catalytic ozonation combined with NH 3 /(NH 4 ) 2 S 2 O 8 absorption was developed for the first time. It consisted of two parts: (1) the catalytic ozonation of NO over FeO x /SAPO-34 to study the effects of the various influencing factors, and (2) the absorption–oxidation of NO x and SO 2 induced by ozone combined with a NH 3 /(NH 4 ) 2 S 2 O 8 solution in a bubble column reactor. In Part 1, results showed that under the optimal condition of a molar ratio of 0.5 for O 3 /NO, a residence time of 3 s, a water vapor volume fraction of 4%, a NO initial concentration of 536 mg/m 3 , and a SO 2 initial concentration of 343 mg/m 3 , the oxidation rate of NO was 55%. The characterizations of poisoned catalyst are briefly discussed. In Part 2, as the gas passed sequentially through the ozonizing reactor and the absorber (NH 3 /(NH 4 ) 2 S 2 O 8 solution of 0.8% ammonia and 0.2 mol/L (NH 4 ) 2 S 2 O 8 ), a NO conversion rate of approximately 92.6% and SO 2 conversion rate of 100% were obtained. The pH of the NH 3 /(NH 4 ) 2 S 2 O 8 solution had a significant impact on the NO conversion. According to the analysis of the composition of products under different pHs, a mechanism of desulfurization and denitrification based on NH 3 /(NH 4 ) 2 S 2 O 8 solutions was proposed. The reaction product as a compound fertilizer contained up to 24.5% nitrogen.
The abuse of agrochemicals has caused serious environmental pollution, raising urgently requirement for sensitive controlled release systems. Biochar supported γ-FeOOH nanoarrays (γ-FeOOH@BC) were synthesized in situ through a two-step pyrolyzation-oxidation procedure. The decoration of γ-FeOOH nanoarray structure significantly enhanced the surface positive charge of the composite (pH zpc increased from 2.7 to 7.8), due to which active substances could be electrostatically self-assembled on γ-FeOOH@BC to realize accurate release by changing the environmental pH. The assembled amounts of QNC and PO 4 3- could reach a value of 94 mg·g −1 and 92 mg·g −1 respectively, and the encapsulation efficiency as well as the release concentration were closely related to the pKa of the substance. 45% (QNC) and 63% (PO 4 3- ) could be released at pH = 7.8 and finally both reached to 88% at pH = 11. After 5 rounds of the sensitivity test, QNC/ PO 4 3- could be well assembled or released by pH adjustment, and the encapsulation efficiency remained above 75%. Meanwhile, the assembly structures could also be self-formed in real soil containing QNC/PO 4 3- and had selective herbicidal activity on barnyard grass plants. This work not only provides a feasible material but also a novel method for self-assembly and controlled release of agricultural chemicals.
Wang Juanjuan,Li Ruochen,Zhang Hui,Wei Gehong,Li Zhefei
Background Excessive application of chemical fertilizer has exerted a great threat to soil quality and the environment. The inoculation of plants with plant-growth-promoting rhizobacteria (PGPR) has emerged as a great prospect for ecosystem recovery. The aim of this work to isolate PGPRs and highlights the effect of bacterial inoculants on available N/P/K content in soil and on the growth of wheat under conditions of reduced fertilizer application. Results Thirty-nine PGPRs were isolated and tested for their growth-promoting potential. Thirteen isolates had nitrogen fixation ability, of which N9 ( Azotobacter chroococcum ) had the highest acetylene reduction activity of 156.26 nmol/gh. Eleven isolates had efficient phosphate solubilizing ability, of which P5 ( Klebsiella variicola ) released the most available phosphorus in liquid medium (231.68 mg/L). Fifteen isolates had efficient potassium solubilizing ability, of which K13 ( Rhizobium larrymoorei ) released the most available potassium in liquid medium (224.66 mg/L). In culture medium supplemented with tryptophan, P9 ( Klebsiella pneumoniae ) produced the greatest amount of IAA. Inoculation with the bacterial combination K14 + 176 + P9 + N8 + P5 increased the alkali-hydrolysed nitrogen, available phosphorus and available potassium in the soil by 49.46, 99.51 and 19.38%, respectively, and enhanced the N, P, and K content of wheat by 97.7, 96.4 and 42.1%, respectively. Moreover, reducing fertilizer application by 25% did not decrease the available nitrogen, phosphorus, and potassium in the soil and N/P/K content, plant height, and dry weight of wheat. Conclusions The bacterial combination K14 + 176 + P9 + N8 + P5 is superior candidates for biofertilizers that may reduce chemical fertilizer application without influencing the normal growth of wheat.
危险品化学品经营许可证（带存储）