烟气脱硫溶液中硫酸根的去除

分别采用石灰乳化学沉淀法和低温结晶法去除烟气脱硫溶液中的SO42-。实验结果表明：在室温、CaO溶液质量分数25%的条件下，石灰乳化学沉淀法对SO42-的去除率仅为59.51%，且向溶液中引入了Ca2+，产生的硫酸钙固体废物难以再生利用；采用低温结晶法处理烟气脱硫溶液，在结晶温度7 ℃、结晶时间3 h、NaOH加入量34.8 g/L的条件下，SO42-的去除率为82.04%、滤液中的ρ（Na+）为3.88 g/L。在现场工业应用试验中，采用低温结晶法去除烟气脱硫溶液中的SO42-，平均SO42-的去除率可达70.00%以上，滤液中的ρ（Na+）小于15.00 g/L。该法可有效抑制烟气脱硫溶液中SO42-含量的增加。     

Facile in situ synthesis of silver nanocomposites based on cellulosic paper for photocatalytic applications

Environmental Science and Pollution Research - In this work, various photocatalysts were synthesized with an impregnation-precipitation process to in situ decorate Ag-based nanoparticles (NPs,...     

Polystyrene nanoplastics affect growth and microcystin production of Microcystis aeruginosa

Nanoplastics are widely distributed in freshwater environments, but few studies have addressed their effects on freshwater algae, especially on harmful algae. In this study, the effects of polystyrene (PS) nanoplastics on Microcystis aeruginosa (M. aeruginosa) growth, as well as microcystin (MC) production and release, were investigated over the whole growth period. The results show that PS nanoplastics caused a dose-dependent inhibitory effect on M. aeruginosa growth and a dose-dependent increase in the aggregation rate peaking at 60.16% and 46.34%, respectively, when the PS nanoplastic concentration was 100 mg/L. This caused significant growth of M. aeruginosa with a specific growth rate up to 0.41 d^?1 (50 mg/L PS nanoplastics). After a brief period of rapid growth, the tested algal cells steadily grew. In addition, the increase in PS nanoplastics concentration promoted the production and release of MC. When the PS nanoplastic concentration was 100 mg/L, the content of the intracellular (intra-) and extracellular (extra-) MC increased to 199.1 and 166.5 μg/L, respectively, on day 26, which was 31.4% and 31.1% higher, respectively, than the control. Our results provide insights into the action mechanism of nanoplastics on harmful algae and the potential risks to freshwater environments.

     

Do trace metal(loid)s in road soils pose health risks to tourists? A case of a highly-visited national park in China

Nowadays, more people tend to spend their recreational time in large national parks, and trace metal(loid)s in soils have attracted long-term attention due to their possible harm to human health. To investigate the pollution levels, potential sources and health risks of trace metal(loid)s in road soils, a total of eight trace metal(loid)s (including As, Cd, Cr, Cu, Ni, Pb, Zn and Hg) from 47 soil samples along roads were studied in the Huangshan National Park in Southeast China. The results showed that the concentrations of As, Cd, Pb, Zn and Hg appeared different degrees of pollution compared with their corresponding background values. According to the pollution indices, Hg and Cd were recognized as significant pollutants presenting moderate to high ecological risk. Combining principal component analysis and positive matrix factorization model, the results showed that traffic, industrial, agricultural and natural sources were the potential origins of trace metal(loid)s in this area, with contribution rates of 39.93%, 25.92%, 10.53% and 23.62%, respectively. Non-carcinogenic risks were all negligible, while the carcinogenic risk of As was higher than the limit (1 $\times$ 10⁻⁶). Moreover, children were more susceptible to trace metal(loid)s by ingestion which appeared to be a more important exposure pathway than dermal contact and inhalation. The contribution rates of different sources to non-carcinogenic risks and carcinogenic risks were similar among children and adults, while traffic and industrial sources have a significant impact on health risks. This study will give more insights to control the environmental risks of trace metal(loid)s in national parks.     

攀钢六号烧结烟气脱硫树脂脱盐工艺参数优化研究

针对攀钢六号烧结烟气脱硫树脂脱盐工艺中存在的脱氯效率低、脱硫剂夹带损耗严重的现状,在现场开展了树脂脱盐工艺参数的优化研究工作。通过对树脂脱盐各步骤工艺参数的优化改进,有效地提高了树脂脱盐的脱氯效率及降低了脱硫剂损耗,为脱硫系统的高效、稳定运行奠定了基础。     

Fe_2O_3和K_2CO_3对钙基添加剂脱硫脱硝的影响

在研究焦炭燃烧过程中使用钙基添加剂固硫的基础上,探讨了Fe_2O_3或K_2CO_3对CaO脱硫脱硝的影响。实验结果表明:添加剂的种类对焦炭燃烧过程中排放的SO_2和NO的浓度及总量均有一定的影响;加入Fe_2O_3或K_2CO_3替代部分CaO后,焦炭燃烧过程中排放的SO_2和NO比单独加入CaO时均有所下降;向焦炭中分别混合3.0%(w)CaO),1.5%(w)CaO+1.5%(w)Fe_2O_3,1.5%(w)CaO+1.5%(w)K_2CO_3的添加剂时,焦炭的SO_2排放总量分别降低了69.93%,75.98%,79.98%,NO排放总量分别降低了64.38%,79.73%,84.14%;加入Fe_2O_3或K_2CO_3后,钙基添加剂的表面性质发生了变化,同时增加了反应的活性中心数,因而复合添加剂能更有效地进行脱硫脱硝。     

Effect of pH on biologic degradation of Microcystis aeruginosa by alga-lysing bacteria in sequencing batch biofilm reactors

In this paper, the effect of pH on biological degradation of Microcystis aeruginosa by alga-lysing bacteria in laboratory-scale sequencing batch biofilm reactors (SBBRs) was investigated. After 10 d filming with waste activated sludge, the biological film could be formed, and the bioreactors in which laid polyolefin resin filler were used to treat algal culture. By comparing the removal efficiency of chlorophyll a at different aerobic time, the optimum time was determined as 5 h. Under pH 6.5, 7.5, and 8.5 conditions, the removal rates of Microcystis aeruginosa were respectively 75.9%, 83.6%, and 78.3% (in term of chlorophyll a), and that of Chemical Oxygen Demand (COD_Mn) were 30.6%, 35.8%, and 33.5%. While the removal efficiencies of ammonia nitrogen (NH ₄ ⁺ - N) were all 100%. It was observed that the sequence of the removal efficiencies of algae, NH ₄ ⁺ - N and organic matter were pH 7.5>pH 8.5>pH 6.5. The results showed that the dominant alga-lysing bacteria in the SBBRs was strain HM-01, which was identified as Bacillus sp. by Polymerase Chain Reaction (PCR) amplification of the 16S rRNA gene, Basic Local Alignment Search Tool (BLAST) analysis, and comparison with sequences in the GenBank nucleotide database. The algicidal activated substance which HM-01 strain excreted could withstand high temperature and pressure, also had better hydrophily and stronger polarity.