Effective adsorption of quadrivalent cerium by synthesized laurylsulfonate green rust in a central composite design

The layered laurylsulfonate intercalated green rust (lauryl-S GR) was synthesized to evaluate the influence of synthesis parameters and aqueous conditions on the adsorption of Ce^IV. The maximum adsorption capacity of 305.58 mg/g by lauryl-S GR was predictably obtained. The pseudo-first-order kinetic model was appropriate in fitting the whole uptake process in a weak acid environment. Three isotherm models including Langmuir, Freundlich, and Tempkin were all reliable in depicting the isotherm adsorption process. The maximum monolayer adsorption capacity of lauryl-S GR towards Ce^IV was 315.46 mg/g. Ce species including CeO and Ce₂O₃ besides CeO₂ were matched in the XPS distribution, directly indicating the reduction reaction brought by Fe^II in the GR occurred to hydrated Ce^IV ions during the adsorption. Nano-sized Ce particles attached to the lauryl-S GRs after the adsorption experiments were observed in the morphological characterization. Flocculated materials were formed on the surface of the lauryl-S GR at a pH of 7, which further reduced the active sites and disrupted the continuous uptake of Ce^IV to the lauryl-S GR. This study expands the application of GRs and supplies an ideal iron-based material for the construction of the affiliated recovery pathway to the traditional separation of Ce.     

Spatiotemporal variations of ambient air pollutants and meteorological influences over typical urban agglomerations in China during the COVID-19 lockdown

To investigate the air quality change during the COVID-19 pandemic, we analyzed spatiotemporal variations of six criteria pollutants in nine typical urban agglomerations in China using ground-based data and examined meteorological influences through correlation analysis and backward trajectory analysis under different responses. Concentrations of PM_2.5, PM₁₀, NO₂, SO₂ and CO in urban agglomerations respectively decreased by 18%–45% (30%–62%), 17%–53% (22%–39%), 47%-64% (14%–41%), 9%–34% (0%–53%) and 16%-52% (23%–56%) during Lockdown (Post-lockdown) period relative to Pre-lockdown period. PM_2.5 pollution events occurred during Lockdown in Beijing-Tianjin-Hebe (BTH) and Middle and South Liaoning (MSL), and daily O₃ concentration rose to grade Ⅱ standard in Post-lockdown period. Distinct from the nationwide slump of NO₂ during Lockdown period, a rebound (～40%) in Post-lockdown period was observed in Cheng-Yu (CY), Yangtze River Middle-Reach (YRMR), Yangtze River Delta (YRD) and Pearl River Delta (PRD). With slightly higher wind speed compared with 2019, the reduction of PM_2.5 (51%–62%) in Post-lockdown period is more than 2019 (15%–46%) in HC (Harbin-Changchun), MSL, BTH, CP (Central Plain) and SP (Shandong-Peninsula), suggesting lockdown measures are effective to PM_2.5 alleviation. Although O₃ concentrations generally increased during the lockdown, its increment rate declined compared with 2019 under similar sunlight duration and temperature. Additionally, unlike HC, MSL and BTH, which suffered from additional (> 30%) air masses from surrounding areas after the lockdown, the polluted air masses reaching YRD and PRD mostly originated from the long-distance transport, highlighting the importance of joint regional governance.     

兼氧条件下厨余垃圾发酵液作碳源的反硝化性能

在兼氧条件下,利用厨余垃圾厌氧发酵液调节反硝化系统的碳氮比（COD/TN,C/N）,并考察了其脱氮性能.结果表明,不同C/N条件下,反应系统均未出现有机物的积累,但高C/N条件下的亚硝酸盐最大积累浓度和积累速率高于低C/N;随着进水C/N的增大,反应整体脱氮率和反硝化速率不断增大,当C/N为13时,反硝化速率达到了最大值,为9.79mg/（gVSS·h）,其脱氮率超过95%;相同C/N条件下,反硝化速率和最大亚硝酸盐积累浓度均与进水硝酸盐浓度成正比.此外,实验结果表明,兼氧条件下的反硝化过程虽不易出现COD残留,但去除单位氮所需的有机物更多,且整体反硝化速率以及亚硝酸盐还原速率均低于厌氧条件.     

保定市2013~2019年秋冬季污染物浓度变化特征

为深入了解保定市空气质量状况,揭示保定市空气污染变化趋势、多尺度变化特征和突变特性,综合利用Morlet小波分析和Mann-Kendall非参数检验方法,对保定市2013~2019年秋冬季PM₁₀、PM_2.5、SO₂、NO₂、CO和O₃-8h 6种常规大气污染物年均浓度和秋冬季污染特征逐日数据进行分析.结果表明：除O₃-8h外保定市其它各污染物年均浓度逐年下降,全年重度污染天数占全年天数的比例从31%下降到6.6%,整体呈好转趋势,但2013~2019年秋冬季重度污染天数占全年重度污染天数的81%~97%,秋冬季污染依然需要重视;小波分析结果显示,保定市秋冬季各污染物浓度存在显著的周期性变化,周期震荡主要在20d准双周、50~90d左右的季节内震荡和90~110d的季节震荡3个时间尺度范围,污染物浓度存在的低频震荡与大气中存在的低频震荡密切相关;历年各污染物污染最严重的月份多集中在12月、1月和2月,主要与污染源排放强度和相对静稳的大气条件有关;各污染物污染序列突变点多集中于10月和3月;2019~2020年秋冬季NO₂呈极显著的下降趋势,且突变点较往年提前1个月,这与疫情期间车辆排放大幅降低有直接关系;SO₂和CO在2013~2014年和2015~2016年秋冬季的突变点时间相近,这可能与冬季居民取暖散煤的不完全燃烧有关,2015年后保定实施了煤改气、煤改电,劣质散煤专项治理等措施后,2种污染物突变点时间存在差异,说明清洁取暖措施对降低SO₂浓度,改善空气质量的效果明显.     

Fe_3O_4、Fe_2O_3对燃煤飞灰比电阻和击穿场强的影响

利用从国内不同燃煤电厂采集的飞灰作为本底灰样，采用试剂添加、磁选分离和高温煅烧等多种方法分别制备Ｆｅ_２Ｏ_３、Ｆｅ_３Ｏ_４含量不等的试样，进而对这些试样的比电阻和击穿场强进行实验研究。研究结果表明，Ｆｅ_２Ｏ_３和Ｆｅ_３Ｏ_４对飞灰的电导性质的影响规律明显不同：Ｆｅ_３Ｏ_４含量提高４％，可使飞灰的比电阻降低约１个数量级，并使霜些飞灰在０．５ｋＶ／ｃｍ场强下产生电击穿；Ｆｅ_２Ｏ_３的比电阻和击穿场强大大高于Ｆｅ_３Ｏ_４，对飞灰的影响不大。实验结果为研究电除尘器收尘极板上飞灰对收尘机理的影响，和飞灰比电阻数学模型的建立提供了依据。     

电活性铝凝剂EAF对炼油废水的絮凝作用

采用电化学方法制取电活性铝凝剂ＥＡＦ．对照测定了３种传统的含铝絮凝剂和ＥＡＦ对模拟和实际含油废水的絮凝净化作用．结果表明，６０℃温度下，ｐＨ＝６～７，ＥＡＦ的用量为１０～３０ｍｇ／Ｌ时，油与ＣＯＤｃｒ去除率分别在９０％和８０％以上．简单讨论了ＥＡＦ的絮凝作用机理．     

环珠江口近地面夜间臭氧上升现象：基于垂直观测的两个个例研究

利用广州塔的O₃观测资料、风廓线雷达和转动拉曼温廓线激光雷达探测的垂直环境气象等观测资料,结合ERA5的近地面风场,对2017年5月6—7日(Case I)和2019年10月1—2日(CaseⅡ)两个典型个例从垂直混合与水平输送的角度进行特征与成因分析.O₃的垂直观测结果表明,夜间残留层可储存日间混合层内的高浓度O₃气团.从垂直混合与水平输送的分析结果表明,残留层O₃的垂直混合及高浓度O₃气团的水平输送是夜间地表O₃的重要来源：夜间存在垂直风切变或边界层抬升,均可加强O₃的垂直混合;珠三角地区背景风表现为在早上偏北风和晚上转换为偏南风,广州与佛山地表O₃浓度上升最显著.此外,夜间O₃浓度上升事件可造成夜间及凌晨O₃ 8 h滑动平均值持续高值,对空气质量和大气氧化性造成一定影响.     

宁东基地大气PAHs污染特征及呼吸暴露风险

利用主动观测技术对宁东能源化工基地大气PM_2.5、PM_1.0和气相中的PAHs浓度水平、族谱特征、时空分布及来源进行研究,并基于该观测数据对居民呼吸暴露健康风险进行评估.结果表明,宁东基地大气PM_2.5、PM_1.0及气相中∑₁₆PAHs浓度范围分别为：17.95~325.12ng/m³、12.66~311.96ng/m³和26.33~97.88ng/m³,年均浓度分别为（99.42±117.48）ng/m³、（78.88±100.58）ng/m³和（57.89±47.39）ng/m³.宝丰基地冬夏季大气PM_2.5、PM_1.0和气相中∑₁₆PAHs浓度水平均明显高于英力特;宝丰和英力特基地冬季大气PM_2.5、PM_1.0中∑₁₆PAHs浓度水平均明显高于夏季浓度.宁东基地大气中∑₁₆PAHs的浓度水平要高于国内外其他城市,大气PAHs污染较为严重.源解析表明夏季宁东基地PAHs的主要排放源是工业煤燃烧和机动车尾气,冬季则主要来自工业煤燃烧和木材、薪柴等生物质燃烧排放.宁东基地人群暴露于大气PAHs可能会造成平均冬季每百万人中约有33~2628人罹患癌症,夏季每百万人中约有11~834人罹患癌症的风险.     

浅谈海上油井安全阀及其控制系统技术的应用

针对实际生产条件，为全面推行海上安全环保、节能与清洁生产，在油井上安装了太阳能安全阀控制系统，对油井生产与安全管理起着重要的作用。     

重庆主城区大气总悬浮颗粒中有机碳和元素碳污染特征分析

在四个季节采样分析的基础上，本文报道了重庆市主城区江北区(商住区)和缙云山(清洁对照点)两个监测点总悬浮颗粒物质量浓度的空间分布和季节变化特征，同时利用热分解示差热导法元素分析仪测定了TSP中的OC和EC浓度，探讨了OC和EC含量并与北京相应功能区的TSP质量浓度及其OC和EC浓度进行了比较。结果表明：重庆市商住区和对照点TSP年均质量浓度均小于北京市商住区和对照点；重庆市商住区OC和EC年均质量浓度高于北京市商住区，北京市对照点OC和EC年均质量浓度高于重庆市对照点。两个城市的四个监测点OC／EC年均值均大于2．0，说明两城市城区二次污染比较严重。