A review of the recent progress in biotrickling filters: packing materials, gases, micro-organisms, and CFD

Organic pollutants in the air have serious consequences on both human health and the environment. Among the various methods for removing organic pollution gas, biotrickling filters (BTFs) are becoming more and more popular due to their cost-effective advantages. BTF can effectively degrade organic pollutants without producing secondary pollutants. In the current research on the removal of organic pollutants by BTF, improving the performance of BTF has always been a research hotspot. Researchers have conducted studies from different aspects to improve the removal performance of BTF for organic pollutants. Including research on the performance of BTF using different packing materials, research on the removal of various mixed pollutant gases by BTF, research on microbial communities in BTF, and other studies that can improve the performance of BTF. Moreover, computational fluid dynamics (CFD) was introduced to study the microscopic process of BTF removal of organic pollutants. CFD is a simulation tool widely used in aerospace, automotive, and industrial production. In the study of BTF removal of organic pollutants, CFD can simulate the fluid movement, mass transfer process, and biodegradation process in BTF in a visual way. This review will summarize the development of BTFs from four aspects: packing materials, mixed gases, micro-organisms, and CFD, in order to provide a reference and direction for the future optimization of BTFs.

The steric effect of benzodifuran based polymers via alkyl side chain manipulation: a simple approach for enhancing the photovoltaic performance

A series of narrow band gap conjugated copolymers with different alkyl side chains were synthesized via Stille copolymerization of benzodifuran (BDF) and benzothiadiazole (BT) monomers.

[Analysis of Industrial VOCs Emission Inventory and Countermeasures in Xiamen]

Based on data from industrial activities and environmental surveys in the six districts of Xiamen, the emission inventory of industrially sourced volatile organic compounds (VOCs) from eight industries in the six districts of Xiamen was calculated for 2019 by applying the emission factor analysis method. The spatial distribution pattern of VOC emission intensity in the six districts of Xiamen was analyzed. VOCs treatment technologies applied in the industries in the VOCs emission inventory were analyzed and countermeasures for improving VOC control were proposed based on the survey of the industries. The results showed that the total VOCs production and VOCs emission from industrial sources in Xiamen was 16027.88 t and 5514.58 t in 2019, respectively. Among them, the VOCs emission from Haicang, Tong'an, Xiang'an, and Jimei districts outside Xiamen Island were 1648.35, 2111.13, 667.52, and 750.48 t, respectively. Fewer VOC emissions from Xiamen Island were observed, which included 292.42 and 44.68 t from Huli and Siming districts, respectively. Except for the Huli District, the spatial distribution of emissions showed a spatial characteristic that the VOCs emission intensities outside Xiamen Island are higher than that of Xiamen Island. Among the eight industries in Xiamen, VOCs emissions were mainly from coating, printing, chemical, and rubber industries, which accounted for 51.21%, 20.18%, 13.63%, and 10.67%, respectively, of the total emissions. The analytic results of the VOCs waste gas disposal technique in Xiamen indicate that, from the perspective of source control, enterprises can effectively control the generation and emission of the VOCs at the source by using low (zero) raw materials. For the terminal disposal procedure, the actual disposal efficiency of UV photolysis/photocatalysis, low-temperature plasma, and biological methods are all lower than 80%, and that of the combined technique of adsorption and catalytic combustion, and the combustion method are both higher than 90%.

Flexible modulation of electronic and magnetic properties of zigzag H-MoS2 nanoribbons by crack defects

The effects of crack defects on electronic and magnetic properties of zigzag MoS₂ nanoribbons are investigated systematically by first-principles calculations based on spin-polarized density functional theory. We find that not only the electronic and spin transport ability of zigzag MoS₂ nanoribbons can be enhanced significantly by the armchair crack defects, but also their magnetism could be modulated flexibly by crack defects. Our study suggests that the introduction of crack defect is a feasible way to modulate the electronic and magnetic properties of zigzag MoS₂ nanoribbons. We further propose that the crack defects may also provide a useful tool for improving the performance of devices.

[Allelopathy effects of ferulic acid and coumarin on Microcystis aeruginosa]

The inhibitory effects and allelopathy mechanism of ferulic acid and coumarin on Microcystis aeruginosa were investigated by measuring the D680 value, the content of chlorophyll-a, the electrical conductivity (EC) and superoxide anion radical O*- value. Ferulic acid and coumarin had allelopathic effects on the growth of M. aeruginosa and promoted the physiological metabolism at low concentrations while inhibited the metabolism at high concentrations. Obvious inhibitory effects were observed when the concentration of ferulic acid or coumarin was over 100 mg x L(-1). The average inhibitory rates reached 80.3% and 58.0% after six days when the concentration of ferulic acid or coumarin was 200 mg x L(-1). The content of chlorophyll-a was decreased while the EC value and O2*- concentration were promoted by higher concentrations of ferulic acid or coumarin, suggesting that the growth of algae was inhibited probably by the damage of cell membrane, increase in the content of O2*- and decrease in the content of chlorophyll-a. In addition, seed germination test elucidated that Ferulic acid was safer than Coumarin.

Fluorescence ratiometric pH sensor prepared from covalently immobilized porphyrin and benzothioxanthene

A fluorescence ratiometric sensor for pH determination is described in this paper. The sensor incorporated the pH-sensitive dye meso-5,10,15,20-tetra-(4-allyloxyphenyl)porphyrin (TAPP) as an indicator and a pH-insensitive dye N-(2-methacryloxyethyl)benzo[k,l]thioxanthene-3,4-dicarboximide (MBTD), a benzothioxanthene derivative, as a reference for fluorescence ratiometric measurement. To prevent leakage of the dyes, both were photocopolymerized with acrylamide, hydroxyethyl methacrylate, and triethylene glycol dimethacrylate on the silanized glass surface. The reproducibility and response time of the prepared sensor were sufficient. Most common coexisting inorganic ions and organic compounds did not interfere with pH sensing. In the acidic pH range from 1.5 to 5.0 the fluorescence intensity ratio of the two dyes varied linearly as a function of pH. The sensing membrane was found to have a lifetime of at least one month. The sensor was applied to the analysis of waste water and artificial samples.

[Detection of Epstein-Barr virus and human papillomavirus in sinonasal malignant neoplasms]

OBJECTIVE

To investigate the existance of Epstein-Barr virus (EBV) and papilloma virus(HPV) in sinonasal malignant neoplasms.

METHOD

EBV and HPV (including HPV6,11,16,18,33) gene were detected in paraffin-embedded tissues with polymerase chain reaction(PCR) from 32 cases of sinonasal malignant neoplasms.

RESULT

EBV was detected in 12(37.5%), HPV in 21(65.6%); The coinfection of EBV and HPV was found in 6 cases with stage III-IV by TNM; 10 cases of nasal polyps contained neither EBV nor HPV.

CONCLUSION

Like HPV, there may be relationship between EBV and sinonasal malignant neoplasms. The coinfection of EBV and HPV is related to stage III-IV by TNM of sinonasal malignant neoplasms.