Latest ArticlesTo control the addition of chlorine disinfectant in drinking water disinfection technology, and to combine the coagulation and disinfection units to reduce energy consumption, a quaternary ammonium chitosan-based flocculant (CTS-g-CHPTAC) with dual functions of flocculation and sterilization was developed. This flocculant effectively removes kaolin and Escherichia coli from wastewater. Material characterization results showed that CTS-g-CHPTAC had a higher cationicity (29.51%) and better water solubility. Flocculation performance tests indicated that the turbidity and bacterial removal rates of CTS-g-CHPTAC reached up to 98.5% and 99%, respectively, when dosages were 0.2mg/L and 2mg/L. Meanwhile, the removal rate was as high as 97% when the dosage of CTS-g-CHPTAC was only 1~1.6mg/L in the mixed simulated wastewater, and the removal rate of mixed pollutants was as high as 95% within the pH range of 5~11. It is speculated that CTS-g-CHPTAC's higher cationic content and rougher surface topography enhance charge neutralization, adsorption bridging, and net sweeping effects, leading to improved flocculation.Furthermore, CTS-g-CHPTAC has bactericidal function, which can interact with the cell wall and cell membrane of E. coli through the quaternary ammonium group on CHPTAC and the amino group on chitosan and kill E. coli.
Based on the LMDI decomposition model, the contribution of driving factors of transportation carbon emissions is quantified. The Tapio decoupling model is used to analyze the relationship between carbon emissions and economic growth, and the efforts made by each factor to achieve decoupling are quantitatively analyzed. The results show that: Economic output is the decisive factors leading to an increase on transportation carbon emissions, with a contribution rate of 115.93% to carbon emissions; Industrial structure has the most significant inhibiting effect on carbon emissions. The decoupling index of transportation carbon emissions in the national, eastern, central, and western regions is all in a downward trend, experiencing the decoupling trend of expansive negative decoupling → weak decoupling → strong decoupling. The driving factors of transportation carbon emissions in the four regions generally show the phased characteristic of "no decoupling effort → weak decoupling effort → strong decoupling effort". Industrial structure has made varying degrees of decoupling effort in 30provinces, with transportation intensity and population size becoming key factors hindering carbon decoupling in the vast majority of provinces.
When drinking water quality and hydraulic conditions change, the solid-liquid balance between pipe scales and water in drinking water distribution systems (DWDSs) will be destroyed, causing iron release and secondary pollution of drinking water. In this paper, dynamic experimental systems were set up to analyze the process of iron release in DWDSs under coupled changes of flow rate (v), pH, sulfate (SO42-), and alkalinity (Alk). Principal component regression was used to establish the model for predicting the release of iron. The results indicated that under the condition of v=0.12m/s, pH=6.5, [SO42-]=250mg/L, and Alk=100mg/L CaCO3, the total iron concentrations in steel and cast iron pipes reached the maximum of 1.423mg/L and 0.184mg/L, respectively. A large amount of flaky and scattered spherical structures were observed in steel and cast iron pipe scales, with α-FeOOH being the main component. After the experiment, the contents of α-FeOOH, γ-FeOOH, and Fe2O3 in both pipe scales increased, while those of Fe3O4 decreased. The predictive model showed that the total iron concentrations were negatively correlated with pH and Alk, and positively correlated with SO42- and v. The order of the influences of the four factors was: v > pH > Alk > SO42-.
This paper chose epoxy resin modified loess as the primary filler for the biological retention tank. It tested 48 different raw material types with varying parameters to improve the ratio of epoxy resin to loess as the benchmark (greater than 2mm/min). The corresponding epoxy resin content is 5% (b5), 10% (b10), 5% (b5d1), and 10% (b10d1). The adsorption capability of the four enhanced materials for NH4+ -N and phosphate was stronger than that of conventional fillers. After the biological retention tank was filled, b5d1had the best average removal of NH4+ -N and COD, reaching 93.97% and 77.5%, respectively. b5also removed NO3- -N(76.6%), TN (62.4%), and TP (98%) more successfully than the other two. Through microbial investigation, b5was found to contain more organisms including Chloroflexi and Steroidobacter that are engaged in the flora process. The NH4+ -N, NO3- -N, TN, TP, and COD can all be efficiently removed by an enhanced loess packed biological tank. According to studies, loess enhanced with epoxy resin has a wide range of promotional uses, may be utilized as biological tank packing, and effectively filters contaminants in runoff rainfall.
Pollen allergy is a global health problem which also has attracted much attention in China, and the incidence is increasing in the northern area. The data of daily airborne pollen concentration, meteorological conditions, vegetation growth and allergic patient were analyzed from 2017 to 2022 in Hohhot of Inner Mongolia Autonomous Region. There were two peaks of pollen dissemination every year. The first peak was in early April, which was a greater proportion of woody plant pollen, with a short duration. The second peak was from August to September, mainly composed of herbaceous plants pollen such as Artemisia of Compositae pollen, with a long duration and had much more serious sensitization effect. The results showed that the effective accumulated temperature of ≥5℃ from January to June was significantly negatively correlated with the start date of the peak pollen dispersal period, while the cumulative precipitation and cumulative sunshine hours from the early stage to the flowering period were significantly positively correlated with the end date of the peak pollen dispersal period. The higher the accumulated temperature was, the earlier the peak period of pollen dispersal started. The end date of peak period would be delayed by the large amount of precipitation and light hours, meanwhile the number of pollen dispersal would increase. There were statistically significant or significant positive correlation between the cumulative value of each meteorological factor or the vegetation index and the monthly average pollen concentration. Appropriate light hours and precipitation, the vegetation would grown well, which would promote pollen dispersal and stimulate an increase in concentration. The number of Allergic Rhinitis patients was consistent with the variation of pollen concentration, and was reaching a peak in August. When the pollen concentration exceeds 100 grains/1000mm2, there was a lag period of 0~4days in the peak of AR treatment, among which the most obvious incremental effect was after 2 days. The number of patients was exponentially related to the pollen concentration in a ten-day time range. The above results would provide some practical reference for pollen concentration meteorological forecasting services and the prevention and treatment of AR caused by pollen allergy.
In this study, Six treatments were established: a control (CK), warming (W), increased precipitation (+P30), decreased precipitation(-P30), increased warming and precipitation (W+P30), and increased warming and decreased precipitation (W-P30). Field experiments were conducted to investigate the effects of warming and precipitation changes on the structure and function of soil bacterial communities in dry-crop farmland. Macro-genome sequencing was exployed to examine the composition, diversity, network structure and metabolic function characteristics of soil bacterial communities under varying treatments. The results demonstrated that the W and W+P30 treatments significantly elevated the relative abundance of Alphaproteobacteria, while the W+P30 treatment notably increased the relative abundance of unclassified Chloroflexi. Conversely, the W, +P30, W+P30, and W-P30 treatments significantly reduced the relative abundance of unclassified Actinomycetia. The +P30 treatment resulted in a significant increase in the Shannon, Simpson and Pielou indices, whereas the W-P30 treatment led to a significant reduction in the alpha diversity index of bacteria. Significant differences were observed in the effects of warming, precipitation changes and their interactions on the β-diversity of the bacterial community. The W, +P30, W+P30 and W-P30 treatments exhibited higher complexity and connectivity than the CK treatment. However, the -P30 treatment exhibited lower relevant parameters than CK. The W, -P30 and W+P30 treatments demonstrated an increase in the number of connectivity nodes, whereas the +P30 and W-P30 treatments did not exhibit this increase. The W treatment led to a notable increase in the relative abundance of the circulatory system, while the +P30 treatment resulted in a significantly decreased the relative abundance of xenobiotics biodegradation and metabolism. The -P30 treatment led to a considerable decrease in the relative abundance of the excretory system, and the W+P30 treatment caused a notable decrease in the relative abundance of nucleotide metabolism. It was observed that warming, precipitation changes (either an increase or decrease in precipitation) and their interaction had significant impact on the structure and metabolic functions of soil bacterial in wheat fields.
The novel PAN/PVDF-HFP/TiO2 nanofibrous membranes with a high performance in PM2.5 removal and high-temperature filtration were developed in this study under co-electrospinning-electrospray strategy, with PVDF-HFP/TiO2 as the functional layer and polyacrylonitrile (PAN) as the base membrane. According to the results, the PHT20nanofibrous membrane achieved an efficiency of 99.8% in capturing particulate matters, a low pressure drop of 67Pa, excellent air permeability, and high thermal stability (to 200℃). Moreover, the results of self-cleaning tests showed that the superhydrophobic surfaces of the PAN/PVDF-HFP/TiO2 nanofibrous membranes were resistant to dust particle contamination. To sum up, the multifunctional PPHT20 nanofibrous membrane developed in this study is an effective solution to dust removal at high temperatures.