基于MODIS_C061的长三角地区AOD与Angström指数时空变化分析

以长三角为研究区,利用AERONET地基观测的气溶胶光学厚度(AOD)数据,验证了基于MODIS_C061深蓝算法(DB)的AOD产品适用于长三角地区.并利用2000～2018年MOD04_L2产品,分析研究区AOD和Angstr?m指数(AE)的时空变化特征.结果表明,长三角地区AOD呈现东部和北部平原地区高、南部和西部山区低的空间分布,AE呈现南部地区高北部地区低的空间分布. 2003～2007年,AOD年均值增长显著,增长率为23%, 2011年以后逐渐下降; 2001～2003年,AE年均值增长迅速, 2012年以后逐渐下降.AOD在长三角地区呈现夏季最高、冬季最低的显著季节性变化,月均值6月最高达0.84, 8月最低为0.40;AE呈现秋季最高,春季最低的季节性变化,月均值9月最高达1.47, 3月最低为1.08.根据AOD与AE的关系,对长三角地区气溶胶类型进行了研究,结果表明人为产生的城市工业气溶胶是该地区主要的气溶胶类型,其次为混合型和清洁大陆型.     

壳聚糖的改性及其去除废水中染料物质的性能研究

采用戊二醛交联FeCl_3制备改性壳聚糖吸附处理染料废水,以20 mg·L~(-1)的亚甲基蓝溶液作为处理对象,探究氯化铁改性壳聚糖(FeCl_3-CTS)投加量、废水p H值、反应时间对其处理亚甲基蓝废水性能的影响,并对吸附动力学、吸附等温线过程进行拟合.结果表明,FeCl_3-CTS对亚甲基蓝废水的处理效果远高于未改性壳聚糖(N-CTS),尤其是在投加量为0.1 g·L~(-1)、p H=6的条件下,经FeCl_3-CTS处理50 min后,亚甲基蓝废水的脱色率高达99.4%,FeCl_3-CTS对亚甲基蓝的吸附容量高达198.8 mg·g~(-1),与N-CTS的54.8%和109.6 mg·g~(-1)相比,均有显著的提高.吸附动力学、吸附等温线拟合结果显示,FeCl_3-CTS对亚甲基蓝废水的吸附过程符合准二级反应动力学方程(R2=0.9992)和Langmuir等温线方程(R~2=0.9995).     

磁性Fen+@GO非均相Fenton催化氧化亚甲基蓝

采用化学共沉淀法制备了磁性Feⁿ⁺@GO（MFGO）纳米复合材料,并将其用于非均相Fenton催化氧化亚甲基蓝（MB）.扫描电镜、透射电镜和光电子能谱分析表明,催化活性粒子（Feⁿ⁺/铁氧化物）成功负载在GO表面.实验研究了pH值、H₂O₂初始浓度、催化剂投加量等因素对MB降解效果的影响.结果表明,H₂O₂、MFGO和H₂O₂+MFGO体系在反应120min后,MB降解率分别达到7.83%、25.58%和99.19%;在优化条件为H₂O₂浓度0.79mol/L、MFGO用量0.75g/L、pH值8时,MB降解率可达99.90%;在pH值为3~11范围内,MB降解率均在99%以上;MFGO经过6次重复使用后对MB的降解率仍可达到95.08%,是一种pH值响应宽、可磁分离回收的新型非均相催化剂.     

Comparison of activated carbon and iron/cerium modified activated carbon to remove methylene blue from wastewater

The methylene blue(MB)removal abilities of raw activated carbon and iron/cerium modified raw activated carbon(Fe–Ce-AC)by adsorption were researched and compared.The characteristics of Fe–Ce-AC were examined by N_2adsorption,zeta potential measurement,FTIR,Raman,XRD,XPS,SEM and EDS.After modification,the following phenomena occurred:The BET surface area,average pore diameter and total pore volume decreased;the degree of graphitization also decreased.Moreover,the presence of Fe_3O_4led to Fe–Ce-AC having magnetic properties,which makes it easy to separate from dye wastewater in an external magnetic field and subsequently recycle.In addition,the equilibrium isotherms and kinetics of MB adsorption on raw activated carbon and Fe–Ce-AC were systematically examined.The equilibrium adsorption data indicated that the adsorption behavior followed the Langmuir isotherm,and the pseudo-second-order model matched the kinetic data well.Compared with raw activated carbon,the maximum monolayer adsorption capacity of Fe–Ce-AC increased by27.31%.According to the experimental results,Fe–Ce-AC can be used as an effective adsorbent for the removal of MB from dye wastewater.     

Influence of sodium dodecyl sulfate coating on adsorption of methylene blue by biochar from aqueous solution

Biochar is regarded as a promising new class of materials due to its multifunctional character and the possibility of effectively coupling different properties. With increasing introduction into the environment, environmental chemicals such as surfactants will load onto the released biochar and change its physicochemical characteristics and adsorption behavior toward pollutants. In this study, sodium dodecyl sulfate(SDS), as one type of anionic surfactant, was coated onto biochar with different loading amounts. The influence of SDS loading onto biochar's physicochemical properties were investigated by Fourier transform infrared(FT-IR) spectroscopy, elemental analysis, zeta potential and Brunauer–Emmett–Teller(BET) surface area and pore size distribution analysis. Results showed that the pore size of the biochar decreased gradually with the increase of SDS loading because of the surface-adsorption and pore-blocking processes; the p H of the point of zero charge(pHPZC) decreased with increasing SDS loading. Although surface-coating with SDS decreased the pore size of the biochar, its adsorption capacity toward Methylene Blue(MB) significantly increased. The biochar-bound SDS introduced functional groups and negative charges to the biochar surface, which could thus enhance the adsorption of MB via hydrogen bonding and electrostatic interaction. The results can shed light on the underlying mechanism of the influence of anionic surfactants on the adsorption of MB by biochar.     

环境中硝酸盐和亚硝酸盐光谱测定法研究进展

主要概述了近年来环境中硝酸盐和亚硝酸盐光谱法测定的研究进展，包括原理、测定参数及其适用范围等。并对各种光谱法的优缺点作出相应评述。     

钐掺杂磷酸铋的制备及其光催化研究

采用一步水热合成法制备不同掺杂量的Sm~(3+)-BiPO_4光催化剂。用XRD,EDS,SEM和DRS手段对光催化剂的特性进行表征。以亚甲基蓝为目标污染物,考察了Sm~(3+)-BiPO_4的光催化活性。结果表明,适量的钐掺杂使BiPO_4光催化活性提高了30%。当钐掺杂量为5%时,紫外光照射90 min,亚甲基蓝的降解率可达86.1%。     

BiPO_4-BiVO_4复合光催化剂的制备及其光催化性能

采用水热法制备了BiPO_4-BiVO_4复合光催化剂,运用XRD,SEM,UV-Vis DRS技术对其进行了表征,并以亚甲基蓝为目标降解物考察了复合光催化剂在模拟太阳光下的光催化性能。实验结果表明:当BiPO_4与BiVO_4的摩尔比(磷钒比)为2∶8时BiPO_4-BiVO_4的光催化性能最优,光照180 min时对亚甲基蓝(初始质量浓度5mg/L)的降解率达96.20%,反应速率常数为0.018 1 min-1,明显优于单纯BiPO_4和BiVO_4。表征结果显示:单斜相的BiPO_4与BiVO_4晶粒实现了复合生长,BiPO_4-BiVO_4(磷钒比2∶8)的晶粒粒径比单纯BiPO_4和BiVO_4小;复合光催化剂在紫外光和可见光区均具有较好的光响应,且其禁带宽度较BiPO_4明显减小。     

秸秆生物质炭的制备及吸附性能研究

将麦秆、向日葵秆和玉米秆低温热解制备生物质炭。采用傅里叶红外光谱、X射线衍射等仪器对其结构进行了表征。研究了热解温度、溶液p H值、初始浓度、吸附时间以及吸附剂用量等因素对各生物质炭吸附亚甲基蓝效果的影响。实验结果表明,3种生物质炭均含有多孔的微晶炭,表面存在大量的活性-OH,-COOH等基团,对亚甲基蓝有较强的吸附作用;在最佳吸附条件下,玉米秆炭、向日葵秆炭以及麦秆炭对亚甲基蓝的吸附容量分别为26.6,26.2,14.7 mg/g。     

可见光响应Pr3+:Y2SiO5/ TiO2薄膜的制备

目的研究层涂法制备Pr~(3+):Y_2SiO_5/TiO_2复合薄膜的结构与可见光催化性能。方法分别以钛酸丁酯(TBOT)和正硅酸乙酯(TEOS)为前驱体,通过溶胶-凝胶法制得TiO_2凝胶和Pr掺杂的Y_2SiO_5凝胶,以碳纤维为薄膜载体,并通过浸渍提拉法制备Pr~(3+):Y_2SiO_5/TiO_2层涂薄膜,研究层涂法制备复合薄膜对复合薄膜结构、形貌以及光催化效果的影响。结果复合薄膜具有明显的分层界限,形貌较平整,有较少龟裂;复合薄膜性能受涂覆次序的影响较大。结论依次将Pr~(3+):Y_2SiO_5和TiO_2涂覆在碳纤维上的复合薄膜具有较好的光催化性能,可见光光照2 h,对亚甲基蓝的脱色率达到94%,其可见光催化效率高于TiO_2薄膜的59%。