磁性氧化石墨烯/壳聚糖制备及其对磺胺嘧啶吸附性能研究

采用一步溶剂热法制备磁性氧化石墨烯/壳聚糖三元复合材料(GO/CS/Fe_3O_4).复合材料的表征结果显示,GO/CS/Fe_3O_4含有丰富含氧官能团,氧化石墨烯片层上均匀负载四氧化三铁磁性粒子,分散到水中的磁性复合材料在外加磁场的作用下,具有良好的磁分离效果.选择磺胺嘧啶为目标污染物考察复合材料吸附性能.结果表明,吸附动力学符合拟二级动力学模型,吸附等温线符合Langmuir模型,在295、303、313 K温度下最大吸附量分别为53.30、60.56、79.23 mg·g~(-1),吸附热力学参数表明GO/CS/Fe_3O_4对磺胺嘧啶的吸附是以物理吸附为主的自发吸热反应.通过不同pH条件下吸附量和Zeta电位分析吸附机理,证明π-π电子共轭效应及静电吸附是复合材料吸附磺胺嘧啶过程中的主导作用力.     

TA修饰GO-ZIF复合纳滤膜对染料MB的去除

采用层层自组装法,在氧化石墨烯（GO）中原位生长ZIF-8,GO-ZIF复合纳滤膜中的GO层间距被成功扩大.通过单宁酸（TA）的修饰,GO-ZIF-TA复合纳滤膜的渗透通道被进一步优化以提高通量和抗污染性能.采用SEM、XRD、FTIR等对复合膜材料进行表征和死端过滤对膜性能进行测试.GO-ZIF复合纳滤膜过滤50 mg·L^-1甲基蓝（MB）时水通量达到40.01 L·m^-2·h^-1,是GO膜水通量的2.4倍,其MB截留率为92.63%.采用TA对GO-ZIF复合纳滤膜进一步改性优化,得到的复合纳滤膜过滤MB时水通量达到47.09 L·m^-2·h^-1,并保持92.13%的MB截留率.TA沉积使膜表面更光滑并改善膜的亲水性,GO-ZIF-TA复合膜表现出良好的抗污染性.     

亚硝酸盐对外碳源反硝化过程N2O还原的影响

本试验通过批次试验考察了亚硝酸盐对外碳源反硝化过程N2O还原的影响.结果表明NO2--N初始浓度为5.92~35.23mg/L时,随着NO2--N浓度的增加,反硝化过程中N2O的积累量逐渐增加;当NO2--N浓度为35.23mg/L时,NO2--N还原量的46.26%被转化为N2O.通过对比试验得出,N2O还原酶与亚硝酸盐还原酶对电子的竞争和游离亚硝酸(FNA)对N2O还原酶的抑制会导致N2O比还原速率下降,造成反硝化过程N2O积累.基于上述试验结果提出,污水处理厂可通过调控运行条件控制NO2--N浓度,降低反硝化过程的N2O的产生与释放;也可以通过短程硝化提高NO2--N浓度,促进反硝化过程N2O的积累,再通过N2O氧化甲烷减少N2O排放,同时提高产能37%.     

掺铈的铜锰钴复合氧化物催化剂对甲苯催化燃烧的性能研究

研究了铜锰钴复合氧化物上掺铈对甲苯完全氧化反应性能的影响。结果表明掺铈的铜锰钴复合氧化物催化剂的催化效果比铜锰、钴锰和钴铜双组分催化剂的催化效果好。以气相色谱为检测手段,用常压气体流动评价装置考察了这四类催化剂对甲苯的温度和空速特性,并对Cu-Mn-Co-Ce-O型催化剂进行了X射线衍射波谱(XRD)表征和BET测量,分析了该催化剂的晶体结构。     

Preparation of SGO-modified nanofiltration membrane and its application in SO42 − and Cl− separation in salt treatment

The lack of fresh water in the world makes the search for an effective method to decontaminate water an urgent priority. An important step is to remove different multivalent ions in salt treatment. Nanofiltration (NF) has been used for treating water containing different kinds of salts. In this work, sulfonate group-modified graphene oxide (SGO) was prepared, and added during the interfacial polymerization (IP) reaction to prepare SGO-modifiedNF membranes (PA-SGO). The chemical composition, structure and surface properties of PA and PA-SGO membranes were characterized by FT-IR, XPS, SEM, AFM, contact angle and zeta potential measurements. Their water flux, salt rejection and anti-fouling abilities were investigated systematically. The testing results showed that the water flux of PA-SGO (0.03% SGO) was 45.85 LMH under a pressure of 0.2?MPa, and the salt rejection varied in the order of Na₂SO₄ (98.99%)?>?MgSO₄ (91.25%)?>?MgCl₂ (42.27%)?>?NaCl (21.96%). An anti-fouling experiment indicated that the PA-SGO membrane had good anti-fouling properties because of its decreased roughness and increased hydrophilicity and electronegativity. The PA-SGO membrane has good potential for use in removing salt ions from water.     

温度对污水脱氮系统污染物去除效果及氧化亚氮释放的影响

污水生物脱氮过程是大气中的氧化亚氮(N2O)的一个重要来源.以anoxic-oxic sequencing batch reactors(A/O SBRs)工艺为研究对象,考察了5组不同温度(10、20、25、30、35℃)条件下系统的污染物去除效果和氧化亚氮释放情况.结果表明,温度对COD的去除无显著影响,但对氮素的去除有明显影响:在一定范围内,随温度的升高氮的去除率升高,但温度超过25℃后,随着温度的上升氮的去除效果下降;温度对氧化亚氮的释放量有重要影响,随温度的升高氧化亚氮的释放量逐渐降低[释放量(以MLSS计)依次为:530.1、260.8、218.3、104.7、57.7μg.g-1].对于A/O SBRs工艺,氧化亚氮的释放主要集中的好氧段,缺氧段几乎无氧化亚氮释放.     

A comparative investigation of NdSrCu_(1-x)Co_xO_(4-δ) and Sm_(1.8)Ce_(0.2)CU_(1-x)Co_xO_(4-δ) (x: 0-0.4) for NO decomposition

A series of single-phase T-structured NdSrCu_(1-x)Co_xO_(4-δ) with oxygen vacancies and T'-structured Sm_(1.8)Ce_(0.2)Cu_(1-x)Co_xO_(4-δ) (x:0-0.4) with oxygen excess were prepared using ultrasound-assisted citric acid complexing method, and characterized by means of techniques such as thermogravimetric analysis and NO temperature-progranuned desorption (NO-TPD). The catalytic activities of these materials were evaluated for the decomposition of NO. It was found that the NdSrCut_xCoxO4_b catalysts were of oxygen vacancies whereas the Sm_(1.8)Ce_(0.2)CU_(1-x)Co_xO_(4-δ) ones possessed excessive oxygen (i.e., over-stoichiometric oxygen); with a rise in Co doping level,the oxygen vacancy density of NdSrCu_(1-x)Co_xO_(4-δ) decreased while the over-stoichiometric oxygen amount of Sm_(1.8)Ce_(0.2)CU_(1-x)Co_xO_(4-δ)increased. The NO-TPD results revealed that NO could be activated much easier over the oxygen-deficient perovskite-like oxides than over the oxygen-excessive perovskite-like oxides, with the NdSrCuO_(3.702) catalyst showing the best efficiency in activating NO molecules. Under the conditions of 1.0% NO/helium, 2800 hr~(-1), and 600-900℃, the catalytic activity of NO decomposition followed the order of NdSrCuO_(3.702)> NdSrCu_(0.8)Co_(0.2)O_(3.736) > NdSrCu_(0.6)Co_(0.4)O_(3.789) > Sm_(1.8)Ce_(0.2)Cu_(0.6)Co_(0.4)O_(4.187)> Sm_(1.8)Ce_(0.2)Cu_(0.8)Co_(0.2)O_(4.104)> Sm_(1.8)Ce_(0.2)CuO_(4.045), in concord with the sequence of decreasing oxygen vacancy or oxygen excess density. Based on the results, we concluded that the higher oxygen vacancy density and the stronger Cu~(3+)/Cu~(2+) redox ability of NdSrCu_(1-x)Co_xO_(4-δ) account for the easier activation of NO and consequently improve the catalytic activity of NO decomposition over the catalysts.     

硝酸浸提拆解废印制电路板元器件技术

研究了废印制电路板在不同浓度硝酸溶液中焊锡完全溶解的时间,以及Sn,Pb,Zn,Fe和Cu的溶解规律及循环利用浸提液的可行性. 结果表明:废印制电路板最佳剥离硝酸浓度为2 mol/L左右,该条件下210 min内废印制电路板上的焊锡完全溶解,元器件能够全部拆除;稀硝酸作为浸提液,可重复利用4次以上,各次循环对焊锡均具有较好的溶解效果;循环利用过程中,Cu反应速率逐次增加,易造成Cu的流失.      

污水处理过程N2O排放：过程机制与控制策略

污水处理生物脱氮过程中氧化亚氮(N₂O)作为直接碳排放源,其大气升温效应较CO₂高出265倍.因此,国际上对N₂O排放机制与控制策略的研究层出不穷.N₂O产生源于硝化与反硝化过程,主要涉及亚硝化(AOB)及其同步反硝化、常规异养反硝化(HDN)、同步异养硝化-好氧反硝化(HN-AD)和全程氨氧化(COMAMMOX)等生物途径,以及硝化过程中间产物NH₂OH与NOH之非生物化学途径.常规硝化与反硝化(AOB+HDN)途径在正常运行工况下N₂O排放量并不是很大,约只占进水TN负荷的1.3%;即使是HN-AD与COMAMMOX代谢过程,两者N₂O产生量也不足TN负荷的0.5%.不可忽视的是AOB亚硝化及其同步反硝化,它们已被确认为是污水处理生物脱氮过程中N₂O排放的首要途径;AOB过程中间产物(NH₂OH与NOH)非生物化学过程以及AOB反硝化生物过程(主途径)共同导致的N₂...     

An inventory of N(2)O emissions from agriculture in China using precipitation-rectified emission factor and background emission

Fertilized agricultural soils are a major anthropogenic source of atmospheric N₂O. A credible national inventory of agricultural N₂O emission would benefit its global strength estimate. We compiled a worldwide database of N₂O emissions from fertilized fields that were consecutively measured for more than or close to one year. Both nitrogen input (N) and precipitation (P) were found to be largely responsible for temporal and spatial variabilities in annual N₂O fluxes (N₂O–N). Thus, we established an empirical model (N₂O–N = 1.49 P + 0.0186 P · N), in which both emission factor and background emission for N₂O were rectified by precipitation. In this model, annual N₂O emission consists of a background emission of 1.49 P and a fertilizer-induced emission of 0.0186 P · N. We used this model to develop a spatial inventory at the 10 × 10 km scale of direct N₂O emissions from agriculture in China. N₂O emissions from rice paddies were separately quantified using a cropping-specific emission factor. Annual fertilizer-induced N₂O emissions amounted to 198.89 Gg N₂O–N in 1997, consisting of 18.50 Gg N₂O–N from rice paddies and 180.39 Gg N₂O–N from fertilized uplands. Annual background emissions and total emissions of N₂O from agriculture were estimated to be 92.78 Gg N₂O–N and 291.67 Gg N₂O–N, respectively. The annual direct N₂O emission accounted for 0.92% of the applied N with an uncertainty of 29%. The highest N₂O fluxes occurred in East China as compared with the least fluxes in West China.