新生态铁的混凝作用探索

利用双氧水和亚铁瞬时反应制备新生态铁作为混凝剂,采用杯罐试验确定了最优制备条件老化时间、酸的添加量、n(H2O2)/n(Fe),并且通过对比新生态铁、硫酸铁、聚合硫酸铁分别对浊度、UV254吸光度的去除效果、沉后水Zeta电位来衡量新生态铁的混凝效果并推测其可能的反应机制.结果表明,老化时间对新生态铁的除浊效果影响极小,可忽略不计;添加酸浓度为[H+]=0.1 mol.L-1时制备出的新生态铁混凝效能最佳;提高n(H2O2)/n(Fe)可显著增强新生态铁的混凝效果,最为经济有效的摩尔比值为0.55.新生态铁对浊度的去除效果与硫酸铁、聚合硫酸铁相近;对UV254吸光度有机物的去除率比Fe2(SO4)3高20%～44%;沉后水Zeta电位随新生态铁投量增加逐渐趋近于0 mV,电中和作用较强.新生态铁是一种具有开发价值的新型混凝剂,老化时间极短,过程简化,原料价格低廉,对浊度、UV254吸光度去除效果较好.     

阴极电极面积和膜面积对H型MFCs产电能力的影响

以生活污水为底物,碳棒作电极,构建H型瓶式微生物燃料电池(microbial fuel cells,MFCs),研究了阴极电极面积和膜面积对电池产电能力的影响.阳极以厌氧污泥作接种体,两室分隔物使用阳离子交换膜(cation exchange membrane,CEM),阳极不使用中介体,阴极使用无催化剂的普通碳电极....     

过碳酸钠降解水相中罗丹明B的实验研究

以水相中的罗丹明B为研究对象,考察了不同条件下过碳酸钠对罗丹明B染料废水的降解作用。结果表明:在一定浓度范围内,过碳酸钠初始浓度与罗丹明B去除速率呈正相关性。碱性和加温能加快反应速率,当温度超过35℃时,罗丹明B褪色率达到90%以上只需要30min。实验还考察了MnO2和254nm的紫外灯对反应的催化作用,结果表明,254nm的紫外灯其能有效的加快反应的进行。     

南京市湖泊沉积物中重金属垂直分布及污染状况评价

为了解城市湖泊沉积物中重金属污染概况及其垂直分布规律,文章选取南京市前湖和月牙湖2个小型浅水湖泊为研究对象,应用电感耦合等离子体原子发射光谱法(ICP-AES)对沉积物中Cd、Cr、Cu、Mn、Ni、Pb和Zn 7种重金属在垂向上的分布进行测定,并采用地累积指数法对重金属的污染情况进行评价。结果表明,月牙湖沉积物中重金属污染程度较前湖严重,整体上,沉积物中7种重金属质量分数由大到小的顺序为:Mn>Zn>Ni>Pb>Cu>Cr>Cd。沉积物中重金属垂向分布规律表明,7种重金属质量分数在表层0~10 cm无明显差别,而10~20 cm波动较大。地累积指数法的评价结果显示,重金属元素中Cd累积最严重,其污染程度处于中度到偏重污染水平之间。前湖沉积物中重金属Zn、Pb和Mn也发生明显累积,而污染较为严重的月牙湖7种元素都处于不同程度的污染状态。     

高海拔环境下离心风机性能数值模拟研究*

为研究高海拔环境下离心风机的运行性能规律,采用计算流体力学（CFD）方法对海拔高度分别为0,1 000,2 000,3 000,4 000和5 000 m条件下的离心风机流场及性能进行三维数值模拟。研究结果表明:相同工况风量条件下,风机内部流场形态不受海拔高度影响,但随着海拔的升高,内流场各处压力绝对值均减小,风机叶片载荷减小,风机蜗壳出口压力及轴功率均大致呈线性趋势降低,海拔每升高1 000 m,风机输出全压及静压分别降低9.3%及9.1%左右,轴功率降低9.0%左右。离心风机效率受海拔高度影响较小,模拟结果表明,各工况条件下,海拔每升高1 000 m,风机全压及静压效率分别平均降低0.21%和0.29%左右。研究为保证高海拔地区离心风机的高效运转及风机选型提供理论参考。     

Long-term exposure to air pollution and cerebrovascular disease: findings from Beijing Health Management Cohort study

● This study explored the long-term association by double robust additive models. ● Individual exposure concentrations were assessed by integrating GAM, LUR and BPNN. ● PM_2.5, SO₂ and NO₂ are positively associated with cerebrovascular disease. ● CO could reduce the risk of cerebrovascular disease with the highest robustness. ● The elderly, women and people with normal BMI are at higher risk for air pollution. The relationship between air pollution and cerebrovascular disease has become a popular topic, yet research findings are highly heterogeneous. This study aims to investigate this association based on detailed individual health data and a precise evaluation of their exposure levels. The integrated models of generalized additive model, land use regression model and back propagation neural network were used to evaluate the exposure concentrations. And doubly robust additive model was conducted to explore the association between cerebrovascular disease and air pollution after adjusted for demographic characteristics, physical examination, disease information, geographic and socioeconomic status. A total of 25097 subjects were included in the Beijing Health Management Cohort from 2013 to 2018. With a 1 μg/m³ increase in the concentrations of PM_2.5, SO₂ and NO₂, the incidence risk of cerebrovascular disease increased by 1.02 (95% CI: 1.008–1.034), 1.06 (95% CI: 1.034–1.095) and 1.02 (95% CI: 1.010–1.029) respectively. Whereas CO exposure could decrease the risk, with an odds ratio of 0.38 (95% CI: 0.212–0.626). In the subgroup analysis, individuals under the age of 50 with normal BMI were at higher risk caused by PM_2.5, and SO₂ was considered more hazardous to women. Meanwhile, the protective effect of CO on women and those with normal BMI was stronger. Successful reduction of long-term exposure to PM_2.5, SO₂ and NO₂ would lead to substantial benefits for decrease the risk of cerebrovascular disease especially for the health of the susceptible individuals.     

Insights into the changes of amino acids,microbial community,and enzymatic activities related with the nutrient quality of product during the composting of food waste

● The highest seed germination index was achieved at 0.3 g/g total solids of food waste. ● Proline was identified as the key amino acid related with the composting process. ● Amino acid metabolism sequences predominated during the whole composting process. This study systematically investigated the changes of amino acids as the composting process of food waste proceeded. It is found that the addition of 0.3 g/g total solids of food waste achieved the highest seed germination index of the product (268 %). The microbial community results indicated that the abundance of amino acid metabolism sequences remained at high levels during the whole composting process. Proline was identified as the key amino acid related with the nutrient quality of product during the composting of food waste. Further plant germination and hydroponic experiments found, that compared with those without the addition of proline, the addition of 50 mg/L proline increased seed germination rate by 20 %, increased shoot length by 3 %, increased root biomass of seedlings by 82 %, and increased leaf biomass of seedlings by 76 %, respectively. Firmicutes, γ-Pseudomonadota, Chloroflexi and Planctomycetes were the key identified bacteria related with the increase of proline during the composting of food waste. Meanwhile, the enzymatic tests of the activities of superoxide dismutase, peroxidase and malondialdehyde indicated that proline did not cause oxidative damage on the growth of plants. This study provided novel insights into the changes of amino acids, microbial community, and enzymatic activities related with the nutrient quality of product during the composting of food waste.     

山东临沂大气夏季典型时段臭氧污染特征及其控制因素分析

2020年6月,在山东省临沂城区开展臭氧(O3)及其前体物观测实验,基于观测数据结合MCM光化学模式模拟,对6月中旬O3污染特例生成机理及控制机制进行了分析.结果 发现,尽管观测期间降水较多,一旦天气转晴,O3迅速积累并超标,1-h和8-h φ(O3)超标天数分别为10d(频率32％)和14 d(45％).O3日变化呈...     

一种易于推广的蓄电池放电测试仪改进装置

依据吴忠供电公司所辖通信独立站点配套蓄电池现状及通信电源蓄电池组核对性放电试验中存在的一些问题,介绍了 １种易于推广的蓄电池放电测试仪改进装置,提高了蓄电池核对性放电工作效率,降低了工作现场安全风险。     

氟喹诺酮类抗生素环境行为及其生态毒理研究进展

氟喹诺酮类抗生素(FQs)是治疗人和动物细菌性感染的高效广谱抗菌药,随着氟喹诺酮类抗生素在禽畜养殖业的广泛使用,由此引起的环境污染受到人们的关注。本文综述了氟喹诺酮类抗生素在水体、土壤/沉积物中的污染现状、吸附降解环境行为及其生态毒理研究进展。FQs抗生素的环境行为和风险应从环境多介质层面进行评估,同时应加强对生态毒性机理以及与其他环境污染物的联合毒性效应的研究。