高温氧化-定向转化法处理草甘膦生产含磷废料

根据草甘膦生产含磷废料的成分特点,先进行预处理及指标调节,然后采用高温氧化-定向转化法进行氧化、聚合反应,得到高品质的磷酸盐产品。实验结果表明:控制预处理后含磷废料中杂质氯化钠质量分数不超3%、p H在7~9,雾化后进入高温氧化-定向转化反应器,在750~800℃下反应50~60 min,产物中焦磷酸钠质量分数达97%以上,含磷废料的COD去除率达99%以上,杂质氯化钠分解率不超0.8%。该方法工艺条件稳定,工程化简单,可以直接得到附加值较高的焦磷酸钠、三聚磷酸钠、六偏磷酸钠等磷酸盐产品,回收产品的经济性较好,推广应用前景广阔。     

Chemical content and source apportionment of 36 heavy metal analysis and health risk assessment in aerosol of Beijing

The concentration levels of 36 airborne heavy metals and atmospheric radioactivity in total suspended particulate (TSP) samples were measured to investigate the chemical characteristics, potential sources of aerosols, and health risk in Beijing, China, from September 2016 to September 2017. The TSP concentrations varied from 6.93 to 469.18 μg/m³, with a median of 133.97 μg/m³. The order for the mean concentrations of heavy metals, known as hazardous air pollutants (HAPs), was as follows: Mn > Pb > As > Cr > Ni > Se > Cd > Co > Sb > Hg > Be; Non-Designated HAPs Metals: Ca > Fe > Mg > Al > K > Na > Zn > P > Ba > Ti > Cu > Sr > B > Sn > I > V > Rb > Ce > Mo > Cs > Th > Ag > U > Pt. The median concentration of As was higher than China air quality standard (6 ng/m³). The gross α and β concentration levels in aerosols were (1.84?±?1.59) mBg/m³ and (1.15?±?0.85) mBg/m³, respectively. The enrichment factor values of Cu, Ba, B, Ce, Tl, Cs, Pb, As, Cd, Sb, Hg, Fe, Zn, Sn, I, Mo, and Ag were higher than 10, which indicated enriched results from anthropogenic sources. Pb, As, and Cd are considered to originate from multiple sources; fireworks released Ba during China spring festival; Fe, Ce, and Cs may come from stable emissions such as industrial gases. The health risks from anthropogenic metals via inhalation, ingestion, and dermal pathway were estimated on the basis of health quotient as well as the results indicated that children faced the higher risk than adults during the research period. For adults, the health risk posed by heavy metals in atmospheric particles was below the acceptable level.

     

柠檬酸强化纳米零价铁活化过硫酸钠体系降解水溶液中的三氯乙烯

采用螯合剂柠檬酸(CA)强化纳米零价铁(nZVI),活化过硫酸钠(PS)体系,降解水溶液中的三氯乙烯(TCE),分别考察了PS、CA、nZVI投加量、溶液初始pH和无机阴离子对TCE降解效果的影响,确定了在TCE降解过程中起主导作用的活性氧自由基,并验证了PS/nZVI/CA体系降解实际地下水中TCE的效果。结果表明:投加适量的CA可以明显提高PS/nZVI体系对TCE的降解效果,但当CA浓度过高时,TCE降解反而受到抑制,过量或不足的PS、nZVI均会降低TCE的降解率;当溶液初始pH为3～9时,PS/nZVI/CA体系可有效降解TCE;溶液中存在的Cl–和HCO_3~-会抑制TCE的降解,其中HCO_3~-的抑制作用大于Cl–;自由基清除实验和电子顺磁共振实验表明PS/nZVI/CA体系中产生了HO·、SO_4~-·和O _2~-·活性氧自由基,其中HO·、SO_4~-·对TCE降解起主导作用;CA的加入有利于实际地下水中TCE的降解,PS/nZVI/CA体系相比PS/nZVI体系,更适应实际地下水中各种水质条件的冲击,具有实际应用前景。     

焦化废水除氰工艺的优化研究

对某焦化厂生化出水进行了除氰研究。对硫酸亚铁混凝除氰法进行了优化,采用沉淀净化法对其出水进行深度处理,考察了工艺中不同影响因素对总氰化物(TCN)去除效果的影响。结果表明,硫酸亚铁混凝除氰法的最佳反应条件为pH 5.00、FeSO4·7H2O投加量500mg/L、反应时间15min、沉淀时间30min;在此条件下,当原水TCN质量浓度为3.1~4.1mg/L时,出水TCN质量浓度达到0.60~0.70mg/L,需作进一步的深度处理。采用沉淀净化法处理硫酸亚铁混凝除氰法出水的最佳反应条件为先同时投加药剂A和药剂B,投加量分别为150、0.75mg/L,反应15min后,再按2mg/L投加药剂C,继续反应3min,最终出水TCN质量浓度低于0.1mg/L,达到《炼焦化学工业污染物排放标准》(GB 16171—2012)要求(氰化物排放限值为0.2mg/L);在此条件下,单位废水处理的药剂成本合计约为0.25元/t。     

菌根在污染土壤生物修复中的作用

菌根是土壤真菌 -植物根系形成的共生体 ,广泛存在于自然界中 ,它能增强植物的吸收能力 ,改善植物的生长 ,提高植株的抗逆能力和耐受能力等。所以 ,菌根化植物可作为很好的生物修复载体。本文主要从无机、有机以及放射性污染 3方面对国内外关于菌根在污染土壤生物修复中的作用进行了综述     

Modeling of land use and reservoir effects on nonpoint source pollution in a highly agricultural basin

Nonpoint source (NPS) pollution is tightly linked to land use activities that determine the sources and magnitudes of pollutant loadings to stream water. The pollutant loads may also be alleviated within reservoirs because of the physical interception resulting from changed hydrological regimes and other biochemical processes. It is important but challenging to assess the NPS pollution processes with human effects due to the measurement limitations. The objective of this study is to evaluate the effects of human activities such as land uses and reservoir operation on the hydrological and NPS pollution processes in a highly agricultural area-the Iowa River Basin-using the Soil and Water Assessment Tool (SWAT). The evaluation of model performance at multiple sites reveals that SWAT can consistently simulate the daily streamflow, and monthly/annual sediment and nutrient loads (nitrate nitrogen and mineral phosphorus) in the basin. We also used the calibrated model to estimate the trap efficiencies of sediment (～78%) and nutrients (～30%) in the Coralville Reservoir within the basin. These non-negligible effects emphasize the significance of incorporating the sediment and nutrient removal mechanisms into watershed system studies. The spatial quantification of the critical NPS pollution loads can help identify hot-spot areas that are likely locations for the best management practices.     

Effects of garbage salvaging and suspended crossbar on microplastic pollution along a typical urban river

Environmental Geochemistry and Health - Microplastic pollution has been considered as a global environmental issue that potentially threatens human health. However, research about microplastic...     

Analysis of the spatial distribution of collectors in dust scrubber based on image processing

The spatial distribution of the collectors in dust scrubber is key in determining the effectiveness of the dust removal process. In the present study, a high-speed camera was used to capture images of the distribution of the collectors. Some of the image information was extracted by image processing, such as the gray mean (GM), the angular second moment (ASM), and the entropy (ENT) from the gray-level co-occurrence matrix of the image. Subsequently, the spatial distribution rules of the collectors were studied by analyzing the spatial proportion, dispersion area, and uniformity and intensiveness of the collectors. It is an intuitive approach and a novel analysis method for the operating state of dust scrubber. The results show that the spatial distribution of the collectors could be better reflected by image processing methods. The dispersion area of the collectors expanded with an increase in the airflow velocity. When the initial liquid level (ILL) was higher, the collectors expanded in an approximate circular shape, and when the ILL was lower the collectors expanded in an approximate sector shape. In general, the variation trend in the spatial proportion enhanced with an increase in ILL and airflow velocity, which is consistent with the uniformity of collectors. When the liquid level was 0?20 mm and the airflow velocity was greater than 6.5 m/sec, the spatial proportion and uniformity of the collectors reached the highest degree. However, the growth rate of the spatial proportion and uniformity of the collectors slowed down and even led to negative growth when the ILL was lower and the airflow velocity was higher. The intensiveness of the collectors was great when the ILL was higher, which was free from the apparent influence of the airflow velocity and the ILL. However, when the ILL was lower, the intensiveness of the collectors was poor, intensifying as the airflow velocity and ILL increased. When the liquid level was ?5?10 mm and the airflow velocity was greater than 8 m/sec, the intensiveness of the collectors reached the highest degree, indicating that a liquid level greater than 0 mm and a higher airflow velocity improved the spatial distribution of the collectors.

Implications: This paper focuses on the spatial distribution of the collectors in dust scrubber. Some of the image information was extracted by image processing, such as the gray mean of the image, the angular second moment, and the entropy from the gray-level co-occurrence matrix of the image. The spatial distribution rules of the collectors were studied by analyzing the spatial proportion, the dispersion area, and the uniformity and intensiveness of the collectors.