浸渍液pH值对V-Mo/Ti脱硝催化剂性能的影响研究

为提升V-Mo/Ti催化剂的脱硝性能,在催化剂制备过程中调节浸渍工艺参数,制备了一系列不同浸渍液pH值的催化剂,采用XRD、N2-吸附脱附、拉曼光谱、UV-Vis、H2-TPR、NH3-TPD等手段对催化剂进行表征,考察了pH值的变化对催化剂物理化学性能的影响,采用固定床微型反应器对催化剂的脱硝性能进行评价。结果表明,降低浸渍液pH值,可以抑制催化剂上VOx物种的聚合,提升催化剂的还原性能,有利于提升催化剂的脱硝效率,降低脱硝反应过程中N2O生成量。同时,浸渍液pH值的变化,也会影响催化剂的酸性性能。当浸渍液pH值低于3.64时,催化剂酸性性能显著降低,造成催化剂脱硝性能降低;当浸渍液pH值控制在3.64时,催化剂的还原性能和酸性性能匹配较好,从而显示了较高的脱硝性能。     

土壤碳淋溶流失研究进展

土壤碳的淋溶流失是指在水的作用下土壤中的碳沿着水文路径转移到水环境的过程。尽管这些流失量有限,却对陆地碳平衡核算具有重要影响。本文在总结了土壤碳淋溶流失研究的重要性、近年来相关领域取得的进展的基础上,指出已有研究的不足有:对土壤无机碳(SIC)的淋溶流失研究薄弱、缺乏野外实地观测、对土地利用变化影响土壤碳淋溶流失的过程与机制认识不足等。今后除了加强以上几个方面的研究外,还要综合利用同位素示踪和在线仪器观测等各种手段,开展"陆地-水生系统连续体"内多界面碳交换的综合研究。     

基于可持续发展的总量预算指标分配方法对比分析研究

阐述了总量预算指标分配的概念,结合环境容量承载水平和总量管理的实际,从理论上建立河南各省辖市可用于社会经济发展的总量预算指标分配模型.针对各分析方法的理论模型进行对比分析,确定合理的分配方案,为后续的实证研究和"十三五"时期河南省总量预算管理提供基础.     

Reversibility of the structure and dewaterability of anaerobic digested sludge

The reversibility of the structure and dewaterability of broken anaerobic digested sludge(ADS)is important to ensure the efficiency of sludge treatment or management processes.This study investigated the effect of continuous strong shear(CSS)and multipulse shear(MPS)on the zeta potential,size(median size,d_(50)),mass fractal dimension(D_F),and capillary suction time(CST)of ADS aggregates.Moreover,the self-regrowth(SR)of broken ADS aggregates during slow mixing was also analyzed.The results show that raw ADS with d_(50) of 56.5μm was insensitive to CSS–SR or MPS–SR,though the size slightly decreased after the breakage phase.For conditioned ADS with d_(50) larger than 600μm,the breakage in small-scale surface erosion changed to large-scale fragmentation as the CSS strength increased.In most cases,after CSS or MPS,the broken ADS had a relatively more compact structure than before and d_(50) is at least 200μm.The CST of the broken fragments from optimally dosed ADS increased,whereas that corresponding to overdosed ADS decreased.MPS treatment resulted in larger and more compact broken ADS fragments with a lower CST value than CSS.During the subsequent slow mixing,the broken ADS aggregates did not recover their charge,size,and dewaterability to the initial values before breakage.In addition,less than 15%self-regrowth in terms of percentage of the regrowth factor was observed in broken ADS after CSS at average velocity gradient no less than 1905.6 sec~(-1).     

哈尔滨市大气主要污染物浓度变化与城市发展因素影响分析研究

采用Daniel趋势检验法对哈尔滨市近年来SO2、NO2和PM10年均浓度变化趋势分析,并对城市总人口与经济、产业结构、民用汽车保有量和能源状况五个城市发展因素进行数据统计分析,用SPSS探究城市发展过程中影响大气污染的因素及相关性.结果表明:浓度变化趋势是SO2明显上升;NO2缓慢上升;PM10整体明显下降,但在2013年点突增至了0.119 mg/m3.SO2与NO2显著相关,相关系数为0.533.经统计,哈尔滨人口经济发展、产业结构调整较为缓慢,全市民用汽车保有量增加并未对NO2浓度影响显著,能源结构依然以煤为主,虽然能源强度提升,但也存在着煤质、散煤的问题.哈尔滨市各城市发展因素与污染物浓度关联度不显著.     

Efficient treatment of azo dye containing wastewater in a hybrid acidogenic bioreactor stimulated by biocatalyzed electrolysis

In this study, a novel scaled-up hybrid acidogenic bioreactor(HAB) was designed and adopted to evaluate the performance of azo dye(acid red G, ARG) containing wastewater treatment. Principally, HAB is an acidogenic bioreactor coupled with a biocatalyzed electrolysis module. The effects of hydraulic retention time(HRT) and ARG loading rate on the performance of HAB were investigated. In addition, the influent was switched from synthetic wastewater to domestic wastewater to examine the key parameters for the application of HAB. The results showed that the introduction of the biocatalyzed electrolysis module could enhance anoxic decolorization and COD(chemical oxygen demand) removal. The combined process of HAB-CASS presented superior performance compared to a control system without biocatalyzed electrolysis(AB-CASS). When the influent was switched to domestic wastewater, with an environment having more balanced nutrients and diverse organic matters, the ARG, COD and nitrogen removal efficiencies of HAB-CASS were further improved, reaching 73.3% ± 2.5%, 86.2% ± 3.8% and 93.5% ± 1.6% at HRT of 6 hr, respectively, which were much higher than those of AB-CASS(61.1% ± 4.7%,75.4% ± 5.0% and 82.1% ± 2.1%, respectively). Moreover, larger TCV/TV(total cathode volume/total volume) for HAB led to higher current and ARG removal. The ARG removal efficiency and current at TCV/TV of 0.15 were 39.2% ± 3.7% and 28.30 ± 1.48 m A,respectively. They were significantly increased to 62.1% ± 2.0% and 34.55 ± 0.83 m A at TCV/TV of 0.25. These results show that HAB system could be used to effectively treat real wastewater.     

Microbial bioavailability of dissolved organic nitrogen (DON) in the sediments of Lake Shankou, Northeastern China

Dissolved organic nitrogen(DON)extracted from Lake Shankou sediments using KCl was isolated into hydrophobic and hydrophilic fractions.The bioavailabilities of the hydrophobic and hydrophilic fractions to three types of bacterial communities collected from sediments,activated sludge and compost products were examined.The DON recoveries obtained by DAX-8 and cation exchange resins treatment were 96.17% ± 1.58% and 98.14% ±0% for the samples obtained from N4 and N14 stations,respectively.After 25 days of incubation at 25°C,most DON(59% to 96%)was degraded.Hydrophilic DON exhibited a higher reduction rate than hydrophobic DON during the growth phase.Untreated wastewater from Changshuihe town was the main degradable DON source to station N4,and 93% of hydrophilic DON and 80% of hydrophobic DON were degraded.Station N14 received a large amount of refractory DON from forest soils and exhibited DON degradation rates of 82% and 71% for the hydrophilic and hydrophobic fractions,respectively.Amino acid contents and fluorescence intensities were also analyzed.Approximately 27% to 74% of amino acids were taken up by day 5,and their concentration gradually increased in the following days due to the decomposition of dissolved proteins.Parallel factor analysis resulted in identification of tryptophan-like proteins,tyrosine-like proteins and FA-like substances.During the growth phase,40%–51% of the tryptophan-like proteins were taken up by bacteria,and the accumulation of tyrosine-like proteins was attributed to the release of biotic substances.The concentration of the FA-like substances decreased due to microbial decomposition.     

Growth inhibition and oxidative damage of Microcystis aeruginosa induced by crude extract of Sagittaria trifolia tubers

Aquatic macrophytes are considered to be promising in controlling harmful cyanobacterial blooms. In this research, an aqueous extract of Sagittaria trifolia tubers was prepared to study its inhibitory effect on Microcystis aeruginosa in the laboratory. Several physiological indices of M. aeruginosa, in response to the environmental stress, were analyzed. Results showed that S. trifolia tuber aqueous extract significantly inhibited the growth of M. aeruginosa in a concentration-dependent way. The highest inhibition rate reached 90% after 6 day treatment. The Chlorophyll-a concentration of M. aeruginosa cells decreased from 343.1 to314.2 μg/L in the treatment group. The activities of superoxide dismutase and peroxidase and the content of reduced glutathione in M. aeruginosa cells initially increased as a response to the oxidative stress posed by S. trifolia tuber aqueous extract, but then decreased as time prolonged. The lipid peroxidation damage of the cyanobacterial cell membranes was reflected by the malondialdehyde level, which was notably higher in the treatment group compared with the controls. It was concluded that the oxidative damage of M. aeruginosa induced by S.trifolia tuber aqueous extract might be one of the mechanisms for the inhibitory effects.