萘降解菌MQ合成靛蓝的研究

利用萘降解菌(丛毛单胞菌)MQ完整细胞对吲哚进行转化合成靛蓝,结果表明菌株MQ具有较好的靛蓝合成能力,靛蓝产量在4h左右即达到稳定.薄层色谱和高效液相色谱分析结果表明,合成的蓝色产物为靛蓝.考察了反应温度及摇床转速对靛蓝合成的影响,结果表明最适温度和转速分别为25℃和150r·min-1.随后,采用表面响应法确定了菌株MQ合成靛蓝的最优条件:菌株接种量OD6602.16,吲哚浓度200.55mg·L-1,pH=6.91.在最优条件下,菌株MQ合成靛蓝的产量为53.05mg·L-1,比初始条件下的产量提高了179%.     

野鸭湖湿地挺水植物磷素截留量动态变化分析

野鸭湖湿地位于官厅水库上游,在截留养分、预防水库水体富营养化方面发挥着重要作用.通过野鸭湖湿地中4种优势挺水植物(茭白、扁秆藨草、香蒲、芦苇)的分布区域研究,分析了植物生物量及养分元素磷含量随季节的动态变化特征,得到了研究区域内4种挺水植物对磷素截留总量的动态变化.结果表明,研究区域内4种优势挺水植物地上部分磷含量为茭白>香蒲>扁秆藨草>芦苇;地下部分磷含量呈现茭白>扁秆藨草>香蒲>芦苇的分布特点;4种植物的地上部分和地下部分磷含量均随生长季节而降低;4种植物的单位面积磷素蓄积能力存在明显差异,表现为茭白>香蒲>扁秆藨草>芦苇的规律,其单位面积蓄积峰值依次为4910、4140、2190和1390g.m-2;研究区域内挺水植物磷素蓄积总量在夏季达到峰值2210.8kg,最小值出现在冬季,为1263.5kg;区域内上、中、下游挺水植物的磷素截留总量依次递减.     

配碳还原回收铜渣中铁、铜的影响因素探讨

采用配碳还原和熔融造渣方法回收铜渣中铁和铜,研究了CaO、Al2O3、CaF2、Na2CO3成分对铁和铜回收效果的影响。在碳氧比1.5和1 450℃条件下,CaO加入量约30%时,铁和铜的回收率较高,分别是93.85%和92.73%。实验表明:添加Al2O3、Na2CO3均降低铁和铜的回收效果,使渣中含铁量增加;CaF2添加量小于2%时,有利于铜渣中铁的回收,CaF2添加量较大时不利于铁和铜的回收。     

以印刷电路板废粉末料制取碱式碳酸铜的研究

印刷电路板废粉末料的资源化和无害化问题日益得到重视。以报废印刷电路板经机械粉碎和分选后的非金属粉(铜含量1%～5%)为原料,采用"氨浸—脱氨—干燥"的工艺制备碱式碳酸铜,设计了实验装置,考察了氨浸分离工艺条件,通过实验验证了其可靠性:铜的回收率达到98.8%以上,获得了纯度不小于98.0%的碱式碳酸铜,采用X射线粉末衍射(XRD)﹑扫描电镜(SEM)和能谱(EDS)方法对产品进行了分析和表征。     

Photodegradation of amoxicillin by catalyzed Fe3+/H2O2 process

Three oxidation processes of UV-Fe³⁺(EDTA)/H₂O₂ (UV: ultraviolet light; EDTA: ethylenediaminetetraacetic acid), UV-Fe³⁺/H₂O₂ and Fe³⁺/H₂O₂ were simultaneously investigated for the degradation of amoxicillin at pH 7.0. The results indicated that, 100% amoxicillin degradation and 81.9% chemical oxygen demand (COD_Cr) removal could be achieved in the UV-Fe³⁺ (EDTA)/H₂O₂ process. The treatment efficiency of amoxicillin and COD_Cr removal were found to decrease to 59.0% and 43.0% in the UV-Fe³⁺/H₂O₂ process; 39.6% and 31.3% in the Fe³⁺/H₂O₂ process. Moreover, the results of biodegradability (biological oxygen demand (BOD₅)/COD_Cr ratio) revealed that the UV-Fe³⁺ (EDTA)/H₂O₂ process was a promising strategy to degrade amoxicillin as the biodegradability of the effluent was improved to 0.45, compared with the cases of UV-Fe³⁺/H₂O₂ (0.25) and Fe³⁺/H₂O₂ (0.10) processes. Therefore, it could be deduced that EDTA and UV light performed synergetic catalytic effect on the Fe³⁺/H₂O₂ process, enhancing the treatment efficiency. The degradation mechanisms were also investigated via UV-Vis spectra, and high performance liquid chromatography-mass spectra. The degradation pathway of amoxicillin was further proposed.     

Heavy metal phytoextraction by Sedum alfredii is affected by continual clipping and phosphorus fertilization amendment

Improving the efficacy of phytoextraction is critical for its successful application in metal contaminated soils. Mineral nutrition affects plant growth and metal absorption and subsequently the accumulation of heavy metal through hyper-accumulator plants. This study assessed the effects of di-hydrogen phosphates (KH₂PO₄, Ca(H₂PO₄)₂, NaH₂PO₄ and NH₄H₂PO₄) application at three levels (22, 88 and 352 mg P/kg soil) on Sedum alfredii growth and metal uptake by three consecutive harvests on aged and Zn/Cd combined contaminated paddy soil. The addition of phosphates (P) significantly increased the amount of Zn taken up by S. alfredii due to increased shoot Zn concentration and dry matter yield (DMY) (P<0.05). The highest phytoextraction of Zn and Cd was observed in KH₂PO₄ and NH₄H₂PO₄ treatment at 352 mg P/kg soil. The amount of Zn removed by phytoextraction increased in the order of 1st clipping<2nd clipping<3rd clipping, and for Cd extraction the order was 2nd clipping<1st clipping<3rd clipping. These results indicate that the application of P fertilizers coupled with multiple cuttings can enhance the removal of Zn and Cd from contaminated soils by S. alfredii, thus shortening the time needed for accomplishing remediation goals.     

大气细颗粒物(PM_(2.5))在环境科学中的研究简述

细颗粒物作为一种重要的大气污染物,其形态与组成非常复杂,本身所具有的毒性和对环境的有害性已日益受到重视。文章对细颗粒物PM2.5在环境科学中的研究进行了概括,提出了自己的一些见解。     

纳米Fe3O4/CeO2-H2O2非均相类Fenton体系对3,4-二氯三氟甲苯的降解

以浸渍法制备的新型纳米Fe3O4/Ce O2为催化剂,3,4-二氯三氟甲苯(3,4-DCBTE)为目标污染物,在Fe3O4/Ce O2-H2O2非均相类Fenton体系中对目标污染物的降解进行研究,考察催化剂的催化效果和温度、p H、H2O2投加量等因素对催化剂催化效果的影响.结果表明,以纳米Fe3O4/Ce O2作为催化剂的非均相类Fenton体系对3,4-二氯三氟甲苯的处理效果极佳;随着温度的升高,纳米Fe3O4/Ce O2的催化效果不断提高;在偏酸性环境中,p H越低催化效果越好,p H=2时反应去除效率可达96.67%;随着H2O2投加量的增加,3,4-二氯三氟甲苯的降解效率先提高后降低,投加量为15 mg·L-1时去除效果最好可达99.47%;随着催化剂投加量的增加,同样出现了处理效果先升高后降低的现象,投加量为0.5 g·L-1时催化效果最好可达99.64%.在以纳米Fe3O4/Ce O2为催化剂的非均相类Fenton体系中,3,4-二氯三氟甲苯的降解符合一级反应动力学,反应所需活化能较低只需30.26 k J·mol-1.     

长江三角洲地区基于喷涂工艺的溶剂源VOCs排放特征

了解挥发性有机物(volatile organic compounds,VOCs)的溶剂源排放特征是制定长江三角洲地区PM2.5和臭氧防控策略的关键.本研究通过罐采样-GC-MS/FID测定了长江三角洲地区重点喷涂行业(集装箱喷涂、造船喷涂、木器喷涂和汽车喷涂业)的VOCs排放特征.结果表明,长江三角洲地区喷涂行业排放的主要VOCs组分为甲苯、二甲苯、乙苯等芳香烃类物质,三者之和占总VOCs的质量分数为79%~99%.生产工艺的不同对VOCs的排放组成影响并不大,废气处理装置中活性炭吸附对VOCs的组成并无明显影响,而催化燃烧的处理过程会使VOCs的排放组成产生显著变化,乙烯排放明显增大,同时也使得催化燃烧处理最大增量反应活性(maximum increment reactivity,MIR)值高于活性炭吸附处理后的MIR值,说明不同的处理措施的使用将影响VOCs对臭氧的生成作用.     

生物操纵方法对水绵(Spirogyra)的调控效应

为探究安全高效调控水绵生长的方法,本研究利用养殖水桶开展了两次生物操纵实验,分别观测了鲤(Cyprinus carpio)、鲫(Carassius auratus)和鲢(Hypophthalmichthys molitrix)在没有营养加富条件下,以及鲫和日本沼虾(Macrobrachium nipponense)在营养加富条件下,对水体中浮游态和固着态水绵(Spirogyra)生长的抑制效果.结果表明,在没有营养加富的水体中,鲤和鲫对水绵不仅没有调控效应,反而会促进水绵的生长.建议在水绵生长旺盛的水体中,一定程度上移除水体中这些鱼类反而可以有效控制水绵的生长.在营养加富条件下,日本沼虾对水绵的控制效应明显.鲫对水绵发挥的作用与水体营养状态存在交互作用,日本沼虾对水绵的抑制效应是否受水体营养状态的影响值得进一步探究.