不同配体合成的锆基MOFs吸附VOCs的试验研究

以对苯二甲酸作为基础配体,采用功能化官能团配体2-氨基对苯二甲酸、1,4-萘二甲酸以及长链配体联苯二甲酸,水热合成UIO-66、UIO-66-NH 2、UIO-66-NDC和UIO-67等含有不同配体的锆基MOFs吸附材料。利用XRD、FTIR、BET表征分析了这4种材料,分别考察了其对甲苯和乙酸乙酯的动态吸附容量。结果表明:具有4种不同配体的MOFs均合成成功;在相对湿度为80%时,UIO-66表现出最高的吸附容量,甲苯吸附量高达139.4 mg/g,乙酸乙酯吸附量为60.8 mg/g;UIO-66具有最佳吸附性能归因于其以微孔为主的孔径结构,BET结果显示其微孔分布在0.5~1 nm之间,有利于小分子VOCs的吸附,展示出良好的应用潜力。

Estimate of contribution of near-inertial waves to the velocity shear in the Bay of Bengal based on mooring observations from2013 to 2014

Near-inertial motions contribute most of the velocity shear in the upper ocean.In the Bay of Bengal(BoB),the annual-mean energy flux from the wind to near-inertial motions in the mixed layer in 2013 is dominated by tropical cyclone(TC)processes.However,due to the lack of long-term observations of velocity profiles,our knowledge about interior near-inertial waves(NIWs)as well as their shear features is limited.In this study,we quantified the contribution of NIWs to shear by integrating the wavenumber-frequency spectra estimated from velocity profiles in the upper layers(40-440 m)of the southern Bo B from April 2013 to May 2014.It is shown that the annual-mean proportion of near-inertial shear out of the total is approximately 50%,and the high contribution is mainly due to the enhancement of the TC processes during which the near-inertial shear accounts for nearly 80%of the total.In the steady monsoon seasons,the near-inertial shear is dominant to or at least comparable with the subinertial shear.The contribution of NIWs to the total shear is lower during the summer monsoon than during the winter monsoon owing to more active mesoscale eddies and higher subinertial shear during the summer monsoon.The Doppler shifting of the M_(2)internal tide has little effect on the main results since the proportion of shear from the tidal motions is much lower than that from the near-inertial and subinertial motions.

Sea level anomalies in the northwestern Pacific during 2011 associated with La Nina and negative Indian Ocean Dipole

The sea level anomalies(SLAs)pattern in the northwestern Pacific delineated significant differences between La Ni?a events occurring with and without negative Indian Ocean Dipole(IOD)events.During the pure La Ni?a events,positive the sea surface level anomalies(SLAs)appear in the northwestern Pacific,but SLAs are weakened and negative SLAs appear in the northwestern Pacific under the contribution of the negative IOD events in 2010/2011.The negative IOD events can trigger significant westerly wind anomalies in the western tropical Pacific,which lead to the breakdown of the pronounced positive SLAs in the northwestern Pacific.Meanwhile,negative SLAs excited by the positive wind stress curl near the dateline propagated westward in the form of Rossby waves until it approached the western Pacific boundary in mid-2011,which maintained and enhanced the negative phase of SLAs in the northwestern Pacific and eventually,it could significantly influence the bifurcation and transport of the North Equatorial Current(NEC).

Intra-seasonal variability of the abyssal currents in COMRA's contract area in the Clarion-Clipperton Zone

In this paper,the intra-seasonal variability of the abyssal currents in the China Ocean Mineral Resources Association(COMRA)polymetallic nodule contact area,located in the western part of the Clarion and Clipperton Fraction Zone in the tropical East Pacific,is investigated using direct observations from subsurface mooring instruments as well as sea-surface height data and reanalysis products.Mooring observations were conducted from September 13,2017 to August 15,2018 in the COMRA contact area(10°N,154°W).The results were as follows:(1)At depths below 200 m,the kinetic energy of intra-seasonal variability(20-100 d)accounts for more than 40%of the overall low-frequency variability,while the ratio reaches more than 50%below 2000 m.(2)At depths below 200 m,currents show a synchronous oscillation with a characteristic time scale of 30 d,lasting from October to the following January;the energy of the 30-d oscillation increases with depth until the layer of approximately 4616 m,and the maximum velocity is approximately 10 cm/s.(3)The 30-d oscillation of deep currents is correlated with the tropical instability waves in the upper ocean.

Evaluation of reanalysis surface wind products with quality-assured buoy wind measurements along the north coast of the South China Sea

Three archived reanalysis wind vectors at 10 m height in the wind speed range of 2-15 m/s,namely,the second version of the National Centres for Environmental Prediction(NCEP)Climate Forecast System Reanalysis(CFSv2),European Centre for Medium-Range Weather Forecasting Interim Reanalysis(ERA-I)and NCEPDepartment of Energy(DOE)Reanalysis 2(NCEP-2)products,are evaluated by a comparison with the winds measured by moored buoys in coastal regions of the South China Sea(SCS).The buoy data are first quality controlled by extensive techniques that help eliminate degraded measurements.The evaluation results reveal that the CFSv2 wind vectors are most consistent with the buoy winds(with average biases of 0.01 m/s and 1.76°).The ERA-I winds significantly underestimate the buoy wind speed(with an average bias of-1.57 m/s),while the statistical errors in the NCEP-2 wind direction have the largest magnitude.The diagnosis of the reanalysis wind errors shows the residuals of all three reanalysis wind speeds(reanalysis-buoy)decrease with increasing buoy wind speed,suggesting a narrower wind speed range than that of the observations.Moreover,wind direction errors are examined to depend on the magnitude of the wind speed and the wind speed biases.In general,the evaluation of three reanalysis wind products demonstrates that CFSv2 wind vectors are the closest to the winds along the north coast of the SCS and are sufficiently accurate to be used in numerical models.

疏水改性ZSM-5的优化制备及其在高湿度下的VOCs吸附性能研究

针对分子筛在高湿度条件下VOCs吸附容量急剧下降的问题,通过优化液相沉积法合成了疏水改性的ZSM-5分子筛.实验选用更加经济环保的乙醇替代甲苯作为改性溶剂,并对两种溶剂的改性效果进行比较,优选出最佳改性条件制备疏水改性ZSM-5,考察了该吸附剂对模拟高湿度有机废气的吸附性能,并采用了SEM、XRD、FTIR、氮气吸脱附、水接触角等方法进行表征.结果表明,作为分散剂,相较于甲苯,无水乙醇更能显著提高分子筛疏水性.在最佳改性条件下,无水乙醇改性的ZSM-5-E_(0)在90%相对湿度下对甲苯的饱和吸附量可达81.9 mg·g^(-1),远高于原样,是甲苯改性的ZSM-5-T_(0)的3倍,循环吸脱附4次后的吸附容量仍在90%以上,对甲苯的吸附符合Langmuir等温吸附模型.实验证明,无水乙醇改性的ZSM-5-E_(0)有优异的VOCs吸脱附性能,具有应用前景.