The performance of slurry photocatalytic ultrafiltration membrane reactor used for degrading the direct scarlet 4BS in dying wastewater was studied. The influences of operating parameters, such as the pH value, amount of photocatalyst TiO2 used and initial 4BS concentration in the wastewater, on the photocatalysis process, as well as the effects of feed rate and operating time on the ultrafiltration processes using PAN700 and PVDF700 membranes were investigated respectively. In order to analyze the adsorption and photocatalytic process of the 4BS on TiO2 catalyst, the Langmuir model was adopted. Results indicate that a maximal adsorption amount of dye on TiO2 occurs at pH=5.5 and the adsorption character is in accord with the Langmuir model. Under the found optimal operation conditions of UV=100 W, T = 20℃, used TiO2 amount of 1 g·L-1 and initial 4BS concentration of 50 m g·L-1,the degradation ratio of 4BS in wastewater after UV irradiation of 60 min can be up to 97.9%. The effects of feed rate and operation time on the performances of ultrafiltration for TiO2 recovery by using two different kinds of membrane, PAN700 and PVDF700, were also studied respectively. The results show that the PAN700 membrane has larger permeate flux and better anti-fouled behavior than those of PVDF700; and according to the filtration cake model, the fouled constant of the separation process β for each membrane was calculated, which shows that the PVDF700 ultrafiltration membrane is more suitable than PVDF700 to be used in the coupling system of photocatalysis and ultrafiltration processes.
A catalytic absorption spectrum method is proposed for determining nitrous. The method is based on the catalytic effect of nitrite ion on the oxidation reaction of naphthol green B in a dilute medium. Linear calibration curves are obtained for NO - 2 from 4 to 14 ug/25ml. The molar absorption coefficient is 1.03×10 5 L.mo1 -1.cm -1 and relation coefficient is 0.9994. The detection limit is 1.3×10 -3ug·m1 -1. The method has been used in determining NO - 2 in tap water and canal water with satisfactory results.
Abstract Background Seed germination, the foundation of plant propagation, involves a series of changes at the molecular level. Poplar is a model woody plant, but the molecular events occurring during seed germination in this species are unclear. Results In this study, we investigated changes in gene transcriptional levels during different germination periods in poplar by high-throughput sequencing technology. Analysis of genes expressed at specific germination stages indicated that these genes are distributed in many metabolic pathways. Enrichment analysis of significantly differentially expressed genes based on hypergeometric testing revealed that multiple pathways, such as pathways related to glycolysis, lipid, amino acid, protein and ATP synthesis metabolism, changed significantly at the transcriptional level during seed germination. A comparison of Σ Z values uncovered a series of transcriptional changes in biological processes related to primary metabolism during poplar seed germination. Among these changes, genes related to CHO metabolism were the first to be activated, with subsequent expression of genes involved in lipid metabolism and then those associated with protein metabolism. The pattern of metabolomic and physiological index changes further verified the sequence of some biological events. Conclusions Our study revealed molecular events occurring at the transcriptional level during seed germination and determined their order. These events were further verified by patterns of changes of metabolites and physiological indexes. Our findings lay a foundation for the elucidation of the molecular mechanisms responsible for poplar seed germination.
Additional file 1 : Table S1. The plastome assembly, annotation information, and distributions of genomic rearrangements for the 75 individuals. Table S2. Detailed information of repeat content for the 75 individuals. Repeat content for the three IR regained plastomes were calculated using only one IR copy. Table S3. Repeats mediated tRNA duplicates. For dispersed repeats, F: forward repeat; C: complement repeat; P: palindromic repeat; R: reverse repeat, and the numbers after the colon represent length of dispersed repeats. For tandem repeats, the numbers before the colon represent length of tandem repeats, the content after the colon represent unit size × copy number. Table S4. Repeats around endpoints of inversions. For dispersed repeats, F: forward repeat; C: complement repeat; P: palindromic repeat; R: reverse repeat, and the numbers after the colon represent length of dispersed repeats. For tandem repeats, the numbers before the colon represent length of tandem repeats, the content after the colon represent unit size × copy number. Palindromic repeat (P) are marked in red. Table S5. Palindromic repeat sequences around endpoints of inversions. Table S6. Repetitive DNA in the acquired introns. Table S7. Nucleotide diversity (pi) for different genes, intergenic regions, and datasets. PC, plastid coding regions; PN, plastid noncoding regions; PCN, the whole plastome. Eight highly divergent coding regions (π > 0.04) and 16 highly divergent non-coding regions (π > 0.1) are marked in red. Table S8. Sequence divergence in accD among the IRLC species. Table S9. Sequence divergence in clpP among the IRLC species. Table S10. Sequence divergence in ycf1 among the IRLC species. Table S11. Sequence divergence in matK among the IRLC species. Table S12. Sequence divergence in rbcL among the IRLC species. Table S13. Information of repetitive elements for the coding sequence (CDS) of three genes (accD, clpP and ycf1) with accelerated substitution rates and two relatively conserved genes (matK and rbcL). There is no coding sequence (CDS) in accD for M. polymorpha because it is a pseudogene (truncated sequence). Table S14. Percent repetitive DNA of the three localized hypermutation regions around the three genes (accD, clpP, and ycf1) with accelerated substitution rates and the remaining plastome sequences. Table S15. Locations of the 75 individuals representing 20 Medicago, Trigonella, and Melilotus species. The individuals for which were planted in laboratory are marked by asterisks. Plastomes of Medicago truncatula were assembled from whole-genome resequencing data downloaded from NCBI (SRR1524305 and SRR965443). The outgroup was downloaded from NCBI (NC_011828.1). The individuals for which were chosen as the representatives of each species are marked in red. Table S16. The 73 protein-coding genes (CDS) shared across 21 taxa included in the phylogenetic analysis. Table S17. Taxa included in the synonymous and nonsynonymous divergence analyses of accD, clpP, ycf1, matK, and rbcL. (√) adopt in analysis, (−) not available in NCBI and not adopt in analysis.
Ecological measures,such as making flow by aeration,modifying sediment,planting aquatic plants,and constructing aquatic microbial population were taken to treat malodorous water from Baidangbang in Changzhou City.After the commissioning and operation for four months,the river water was significantly improved.DO was increased from 0.21 mg/L to 3.8 mg/L,the removal rates of COD,BOD5,ammonia nitrogen and TP were 57.8%,72.4%,41% and 55.6% respectively,and the transparency was increased from 15 cm to above 40 cm.The findings show that it is technically feasible to use the above-mentioned measures to remove organic compounds,ammonia nitrogen and TP and to add DO and transparency.In addition,the environmental regulatory enhancement and the regular operation management are helpful to restore the ecological environment of the river system.
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