Quantitative and qualitative characteristics of dissolved organic matter from eight dominant aquatic macrophytes in Lake Dianchi, China

The aim of this research was to determine and compare the quantitative and qualitative characteristics of dissolved organic matters (DOM) from eight aquatic macrophytes in a eutrophic lake. C, H, N, and P in ground dry leaves and C, N, and P in DOM of the species were determined, and C/N, C/P, C/H, DOC/C, TDN/N, TDP/P, DOC/TDN, and DOC/TDP were calculated. Chemical structures of the DOM were characterized by the use of multiple techniques including UV-visible, FT-IR, and ¹³C CP/MAS spectra. The results showed subtle differences in quantity and quality of DOM among species and life-forms. Except oriental pepper which had a C/H of 0.7, C/H of all the other species was 0.6. C/N and C/P of ground leaves was 10.5–17.3 and 79.4–225.3, respectively, which were greater in floating and submerged species than in the others. Parrot feather also had a small C/P (102.8). DOC/C, TDN/N, and TDP/P were 7.6–16.8, 5.5–22.6, and 22.9–45.6 %, respectively. Except C/N in emergent and riparian species, C/N in the other species and C/P in all the species were lower in their DOM than in the ground leaves. DOM of the macrophytes had a SUVA₂₅₄ value of 0.83–1.80. The FT-IR and ¹³C NMR spectra indicated that the DOM mainly contained polysaccharides and/or amino acids/proteins. Percent of carbohydrates in the DOM was 37.3–66.5 % and was highest in parrot feather (66.5 %) and crofton weed (61.5 %). DOM of water hyacinth, water lettuce, and sago pondweed may have the greatest content of proteins. Aromaticity of the DOM was from 6.9 % in water lettuce to 17.8 % in oriental pepper. DOM of the macrophytes was also different in polarity and percent of Ar–OH. Distinguished characteristics in quantity and quality of the macrophyte-derived DOM may induce unique environmental consequences in the lake systems.     

超声前处理强化活性炭吸附活性艳红X-3B染料废水

探究了超声前处理活性艳红X-3B染料废水强化活性炭吸附降解性能及不同超声参数的影响规律,包括超声功率和超声时间。研究结果表明,超声前处理活性艳红X-3B染料废水可通过空化效应使有机大分子裂解为小分子易于被活性炭吸附,同时可强化其到活性炭微孔中传输,提高了活性炭吸附降解性能,最佳超声功率为320 W。浓度越高,所需超声时间越长,当超声达到一定时间后,继续超声不会影响染料分子的吸附。超声前处理虽然不会改变吸附平衡时间,但可有效增加活性炭处理活性艳红X-3B染料废水的饱和吸附量。     

氧化物催化剂对非热等离子体催化降解甲苯的影响

考察了在干燥气氛下不同氧化物催化剂对非热等离子体催化降解甲苯的影响。从甲苯降解率、碳平衡、CO2选择性和O3去除4个方面,对比了氧化物催化剂的介电性能、表面供氧能力和比表面积与多孔结构对反应产生影响的强弱。结果表明,催化剂的介电性能有利于甲苯降解率、碳平衡和O3产量的提高,但对CO2选择性和O3去除的影响极小;一定能量密度下,催化剂比表面积与多孔结构对CO2选择性和O3去除所产生的影响要强于介电性能;催化剂表面供氧能力可明显促进反应的进行,其对反应所产生的影响要强于比表面积与多孔结构。     

喀喇昆仑山-昆仑山植物区系的一般特征及植物资源的保护与开发利用

本文根据1987—1988年两年考察的结果,初步讨论了喀喇昆仑—昆仑山地区植物区系的一般特征:1.植物种类比较贫乏高等植物仅243属约700种;2.北温带分布型属占绝对优势;3.以桑株河谷为界,昆仑山西段与东段的植物区系有很大差异;4.无严格的特有属,但种的分化强烈,种群数量大。本区由于极端干旱,自然生态系统十分脆弱,而森林和各类天然植被在维护本区自然生态系统平衡方面,起着十分重大的作用。在严格保护使森林和各类自然植被不致破坏的前提下,提出本区最有可能开发利用的植物资源是药用植物资源,除许多著名的中药外,应着重开发利用红景天属(Rhodiola)、风毛菊属(Saussurea)、葱属(Allium)的药用植物,并对当地的民族药物矮膜苞芹(Hymnolaena nana)等,进行深入研究。     

Degradation of bisphenol A in aqueous solution by persulfate activated with ferrous ion

Degradation of bisphenol A (BPA) in aqueous solution was studied with high-efficiency sulfate radical (SO₄ ^?·), which was generated by the activation of persulfate (S₂O₈ ^2?) with ferrous ion (Fe²⁺). S₂O₈ ^2? was activated by Fe²⁺ to produce SO₄ ^?·, and iron powder (Fe⁰) was used as a slow-releasing source of dissolved Fe²⁺. The major oxidation products of BPA were determined by liquid chromatography-mass spectrometer. The mineralization efficiency of BPA was monitored by total organic carbon (TOC) analyzer. BPA removal efficiency was improved by the increase of initial S₂O₈ ^2? or Fe²⁺ concentrations and then decreased with excess Fe²⁺ concentration. The adding mode of Fe²⁺ had significant impact on BPA degradation and mineralization. BPA removal rates increased from 49 to 97 % with sequential addition of Fe²⁺, while complete degradation was observed with continuous diffusion of Fe²⁺, and the latter achieved higher TOC removal rate. When Fe⁰ was employed as a slow-releasing source of dissolved Fe²⁺, 100 % of BPA degradation efficiency was achieved, and the highest removal rate of TOC (85 %) was obtained within 2 h. In the Fe⁰–S₂O₈ ^2? system, Fe⁰ as the activator of S₂O₈ ^2? could offer sustainable oxidation for BPA, and higher TOC removal rate was achieved. It was proved that Fe⁰–S₂O₈ ^2? system has perspective for future works.     

利用废弃物衍生燃料的热化学处理法制富含氢气合成气

为了探讨利用热化学方式从城市垃圾中制取富含氢气合成气过程的要素影响,解析氢气发生特性及其与主要影响要素之间的关系。在分析了城市生活垃圾组分特性的基础上,将其加工成组分均一的废弃物衍生燃料(refuse derived fuel,RDF),并在700、800和900℃等3个温度条件下,分别开展了RDF的热解、气化及水蒸汽气化等实验。研究表明,RDF的加工不但可有效降低垃圾含水率,还可将垃圾热值提高近1倍。温度和添加水蒸汽是从RDF中制取富含氢气合成气过程中的关键影响要素。其中,温度对氢气生成起到至关重要的决定作用,温度的提高对促进H2浓度的提高有利,同时,在气化过程中添加水蒸汽,可有效促进CO和H2等有价气体组分生成。在900℃的高温水蒸汽气化处理过程中,可获得H2浓度最高为34.13%的合成气。另外,800℃热解过程所产生的合成气热值最高,达到14 509 kJ/Nm3。     

超滤膜深度处理染整废水的膜污染机理

实验采用不同规格和材料的超滤膜进行染整二级尾水分离实验,对超滤膜污染机理及影响因素进行了分析。实验采用红外光谱分析了聚醚(PES)膜、聚砜(PSF)膜和聚醚酰亚胺(PEI)膜3种超滤膜材料,对比了污染前后膜面的接触角以及不同切割分子量对膜通量及出水水质的影响,并利用线性化的Herman堵塞模型拟合了不同分子量超滤膜的堵塞模型,初步探讨了超滤膜的污染机理。实验结果表明,膜材料表面亲水性基团的多少与初始膜通量大小成正比,出水COD值随超滤膜切割分子量减小而减小。切割分子量同为2 000 Da的3种超滤膜中,PES膜的处理效果最佳,出水COD平均值为47.81 mg/L;PEI膜通量最高,平衡通量可达50 L/(m2.h);切割分子量为1 000、10 000的超滤膜堵塞机理符合滤饼过滤模型,100 000的超滤膜堵塞机理更接近于完全堵塞模型;1 000的聚醚砜材质膜(PES)更适合此类废水的深度处理。     

Biotreatment of chromite ore processing residue by Pannonibacter phragmitetus BB

Chromite ore processing residues (COPR) is the source of the Cr(VI) contamination in the environment. Pannonibacter phragmitetus BB was used to treat two different types of COPRs in this research. The water-soluble Cr(VI) of COPR A and B is 3,982.9 and 1,181.4 mg/kg, respectively. In the column biotreatment process, P. phragmitetus BB can reduce Cr(VI) in the leachate to an undetectable level at the flow rate of 1 and 2 ml/min. In the direct biotreatment process, Cr(VI) in the liquid supernatant of COPR A and B decreased from 265 and 200 mg/l to 145 and 40 mg/kg after 240 h of incubation. In one-step and two-step biotreatment processes, Cr(VI) in the liquid supernatant of both COPRs can be reduced to an undetectable level. The toxicity characteristic leaching procedure results indicate that the Cr(VI) concentration of treated COPR A (3.48 mg/l) is lower than the identification standards for hazardous wastes of China (5 mg/l) (GB 5085.6-2007). The information obtained in this study has significance for the application of P. phragmitetus BB to remediate COPR contamination.     

Sedimentary record of polycyclic aromatic hydrocarbons and DDTs in Dianchi Lake, an urban lake in Southwest China

Unique time trends of polycyclic aromatic hydrocarbons (PAHs) and dichlorodiphenyltrichloroethanes (DDTs) were found in a dated sediment core from Dianchi Lake (DC), an urban lake in Southwest China. The temporal trend of PAHs in DC was not only different from those in China's coastline and remote lakes of China, but also different from those in more developed countries. Identification of sources suggested that PAHs in DC originated primarily from domestic combustion of coal and biomass. However, a change of source from low- and moderate-temperature combustion to high-temperature combustion processes was observed. Different from those in China's coastline and some developed countries, the temporal trend of DDTs in DC mirrored the historical usage of DDTs in China, with erosion of soils and surface runoff from its drainage area the most likely routes of DDT introduction to the lake. Rapid urbanization and industrialization in its catchment, effective interception of point-source pollution, and changes in sources of energy during the last few decades have significantly influenced the vertical profiles of PAHs in DC.     

The effects of residual tetracycline on soil enzymatic activities and plant growth

A pot trial was carried out to investigate the adverse effects of tetracycline (TC) on soil microbial communities, microbial activities, and the growth of ryegrass (Lolium perenne L). The results showed that the presence of TC significantly disturbed the structure of microbial communities and inhibited soil microbial activities in terms of urease, acid phosphatase and dehydrogenase (p < 0.05). Plant biomass was adversely influenced by TC, especially the roots with a reduction of 40% when compared with the control. Furthermore, TC decreased the assimilation of phosphorus by the plant although the concentration of phosphorus was increased by 20% due to decreased plant biomass. TC seemed to increase the concentration of dissolved organic carbon (by 20%) in soil. The findings implied that the agricultural use of animal manure or fishpond sediment containing considerable amounts of antibiotics may give rise to ecological risks.