石油烃混合降解菌对汽油污染土的降解条件优化试验研究

为测定实验室提取的5种石油烃降解菌的混合菌悬液对汽油污染土的降解效果,利用气相色谱-质谱联用仪对经过降解菌降解的汽油污染土化合物进行定性分析,以鉴定此混合菌悬液对汽油污染土是否有降解能力;考虑pH值、温度、土壤含水率及降解菌接种量等因素,采用单因素试验和多因素正交试验进行降解率测定,以优化此混合菌悬液对汽油污染土的降解条件。试验结果表明,单因素试验条件下,经过试验前后化合物组分比较发现,实验室提取的5种混合降解菌对汽油污染土有良好的降解能力;由相对峰面积比图发现,温度和降解菌接种量相对于含水率和pH值这两个因素来说,对混合降解菌降解效果的影响更为显著;当pH值在6～8、降解温度在30～35 ℃、含水率在15%～25%、降解菌接种量在1～2.5 mL范围时,混合菌悬液的降解效果相对明显。多因素正交试验条件下,混合菌悬液的最佳降解条件是：温度为32 ℃,pH值为7,降解菌接种量为1 mL,含水率为25%。     

氨氮降解菌的分离、鉴定及降解效果初步研究

以(NH4)2SO4为唯一氮源的培养基中,从活性污泥中分离筛选出8株具有氨氮降解能力的菌株,根据各菌株之间降解率及生长情况的比较,从中筛选出1株对氨氮降解效果较为明显的菌株NX3,经形态学和生理特性初步鉴定其为芽孢杆菌属(Bacillus),分别测定了在不同的氨氮初始浓度、pH值、温度下菌株NX3对培养基中氨氮的降解效果,实验结果表明在初始氨氮质量浓度300mg/L、pH值7.0、温度30℃时,该菌株对氨氮降解效果较好,降解率为45.53%。     

乙酰嘧啶分解菌的筛选及其降解性能的研究

从某制药厂废水处理好氧池的活性污泥中,驯化、分离得到4株能以乙酰嘧啶为唯一碳源、氮源进行生长的菌株,分析了它们的表观特点,并对其降解乙酰嘧啶的能力和降解动力学的特性进行了研究.结果表明:4种菌株的生长均符合S型生长曲线;7 d内,这4种细菌对初始浓度为50 mg/L的乙酰嘧啶的降解量分别为34.47、27.09、38.52、9.79 mg/L.     

LAS优势降解菌对洗浴废水处理效果的实验研究

针对洗浴废水中LAS难以去除及对微生物具有一定毒性的特点,通过对微生物样品的富集培养、纯种分离获得LAS优势降解菌,并对其进行了菌种鉴定;测定结果表明:LAS优势降解菌属革兰氏阴性菌(G-),并呈短杆状;硝酸盐还原阳性菌;甲基红阴性,可以将产生的酸性物质转化为中性;经需氧性实验测定其为好氧菌。在此基础上,通过静态实验确定LAS优势降解菌处理洗浴废水的最佳反应条件及处理效果;研究结果表明:在LAS降解优势菌菌悬液(OD=0.4)接种量为4%、摇床振荡频率150r·min-1、水样pH=7的条件下,洗浴废水水样中LAS、COD和NH3-N去除率分别为77.89%、86.37%和62.75%。     

光化学、吸附和光催化对甲醛降解作用的对比研究

以甲醛为例,介绍了光化学反应、吸附作用和光催化氧化作用对挥发性有机化合物降解过程的作用机理;通过实验数据比较了以上三种作用对甲醛的降解效果;肯定了光催化氧化作用对甲醛降解的高效性;证明了将纳米半导体TiO2覆膜于普通滤料上,消除挥发性有机化合物以提高室内空气品质是完全可行的。     

3株耐盐细菌对萘、菲、惹烯和苯并[α]芘的降解性能

为研究3株耐盐细菌(S1Microbacterium sp.、G12Zhihengliuella sp.和Y3Pseudomon putida)对多环芳烃的利用性能,分别测定其在以萘、菲、惹烯和苯并[α]芘为唯一碳源并添加不同浓度葡萄糖(0、0.5、1.0、1.5 g/L)的无机盐培养基中的生长情况,采用气质联用(GC-MS)技术测定了3株菌在上述培养基中作用7 d后对4种多环芳烃(PAHs)的降解性能,同时测定出3株菌的生长量并计算出单位细胞的降解效率。结果表明:3株菌均能够利用4种PAHs作为碳源,且在无糖的萘-无机盐培养基的中生长量高于其他3种PAHs-无机盐培养基,在萘、菲、惹烯-无机盐培养基的生长量均与含糖量成正比,但0.5、1.0、1.5 g/L葡萄糖组间无显著性差异(P>0.05);添加1.0 g/L葡萄糖时,3株菌对4种PAHs的降解率均可达到最高值,对萘的降解率分别提高了44.06%(S1)、70.56%(Y3)和50.98%(G12),对菲的降解率分别提高了49.66%(S1)、45.87%(Y3)和38.29%(G12),对惹烯的降解率分别提高了66.13%(S1)、61.31%(Y3)和56.20%(G12),对苯并[α]芘的降解率分别提高了69.42%(S1)、65.79%(Y3)和65.01%(G12)。研究表明,3株菌对4种PAHs单个细胞降解速率均随葡萄糖浓度的增加而大幅度降低,呈剂量反比关系。     

Degradation of organic matter from black shales and charcoal by the wood-rotting fungus Schizophyllum commune and release of DOC and heavy metals in the aqueous phase

We investigated the degradation of refractory organic matter (OM) by the basidiomycete fungus Schizophyllum commune to understand the release of dissolved organic compounds, heavy metals and sulfur. The investigated OM consisted of: charcoal, the short time end product of high temperature wood alteration in the absence of oxygen and composed mainly of pure OM; and black shales composed of clay minerals, quartz, sulfides and OM formed geogenically in an abiotic long-term process. In both cases, the OM fraction contains mainly polyaromatic hydrocarbons. We investigated the degradation of these fractions by a wood-rotting basidiomycete, which is able to produce exoenzymes like peroxidases and laccases. These enzymes can perform radical reactions to oxidize OM (like lignin) and therefore hypothetically are able to degrade OM from charcoal and/or low grade metamorphic black shales. Release of new components into dissolved organic carbon (DOC) could be detected in both cases. The attack on OM in the case of black shales coincided with the release of the heavy metals Fe, Mn and Ni. By following sulfur concentrations throughout the experiment, it was shown that heavy metal release is not due to pyrite oxidation. Ground black shale and charcoal samples were inoculated with S. commune in a diluted minimal medium containing aspartic acid and glucose. The aqueous and solid phases were sampled after 1, 7, 28 and 84 days. DOC was measured as non purgeable carbon and characterized by size exclusion chromatography and UV detection. Carbon concentrations of the solid phase were determined by element analyses. After initial decrease of the DOC concentrations due to the degradation of the carbon source provided with the medium, DOC increased up to 80 mg/l after 84 days. Carbon decreased in the solid fraction confirming that this carbon was released as DOC by the fungus. The newly generated DOC formed larger agglomerations than the DOC of the growth medium. The investigation proved that the degradation of persistent carbon sources, such as charcoal and black shale, is accelerated by fungal activity. Consequently, the associated release of heavy metals is also accelerated by the fungus. Main products of the biological degradation processes were organic heavy metal complexes which can enter the environment.     

水力空化与生物法联用降解苯酚的试验研究

本试验将水力空化作为生物法处理含苯酚废水溶液的预处理工艺,研究了苯酚废水中COD的去除率,并与单独用生物法处理苯酚废水溶液后的COD去除率作对比,确定水力空化作为难降解废水预处理工艺的可行性。     

ZnO/O3工艺降解水中微量有机物的研究

以实验室制备的粉末氧化锌(ZnO)为催化剂,考察了ZnO/O3工艺去除水中有机物的效能.采用总有机碳(TOC)指标反映水中有机污染物的含量.结果表明:臭氧投量为1 mg/L、ZnO投量为300 mg/L时,反应60 min后ZnO-O3工艺对TOC的去除率为46%,比单独臭氧化提高了1倍;反应温度明显影响该工艺对有机物的降解效果,在水温为5,10,20和25 ℃时,TOC的去除率分别为17.5%,31.5%,45.9%和51.3%.臭氧浓度和催化剂投量的增加,可以提高TOC的氧化降解效率.     

光催化纳米建筑涂料降解气态氨的研究

以掺加纳米TiO2制备的光催化纳米建筑涂料为催化剂,研究了气态氨在紫外光照射下的降解,探讨了TiO2光催化剂的类型、催化剂用量、氨的初始浓度等对氨光催化降解的影响,并对氨的降解产物进行了分析,探讨了氨的光催化降解机理.结果表明,掺加锐钛型纳米TiO2的光催化纳米建筑涂料具有较高的光催化活性,其光催化活性随着纳米TiO2添加量的增加而提高,氨的光催化降解转化率随着氨初始浓度的增加而下降.氨的降解产物主要为NO3-和NO2-,涂料的光催化活性通过水洗清除催化剂表面的降解产物后可得到有效恢复.     

利用HPLC-MS研究高锰酸钾对水中MC-IR的降解作用

采用液相色谱串联质谱(HPLC-MS)的检测方法,研究了高锰酸钾对MC-LR降解作用.结果表明,HPLC-MS方法可靠,灵敏度高,在5～500 mg/L范围内,MC-LR浓度与HPLC-MS峰面积呈线性关系,相关系数R2为0.999 3;在常规的氧化剂投加量和反应时间条件下,高锰酸钾对MC-LR表现出良好的降解作用,降解反应符合一级动力学模式;通过分析质谱扫描图,确定了降解产物的分子量,并进一步探讨了MC-LR的氧化降解机理.     

Cu-TiO2光催化降解甲醛气体的研究及应用

采用环境测试舱模拟可见光下的室内环境,以甲醛气体的光催化降解为探针反应,评价了通过纳米杂化和溶胶-凝胶技术制备的Cu-TiO2纳米晶体对甲醛气体的降解效果.用X射线衍射和紫外-可见分光光谱表征了掺杂纳米TiO2的晶体结构与光学性能.结果表明,Cu-TiO2在可见光源下具有比纯TiO2更好的光催化降解甲醛气体能力,并探讨了其在新型环保建材方面的应用.     

Study of tropaeolin degradation by iron--proposition of a reaction mechanism

The degradation of tropaeolin by iron was studied under oxidizing and inert atmospheres. The products were identified by various chromatographic and spectroscopic methods. Under inert atmosphere, the proposed model of mechanism is based on the adsorption of tropaeolin by the sulfonate function on the solid iron, followed by a reduction of the –N=N– bond with formation of 1-amino-2-naphthol and sulfanilic acid. These two intermediaries were reduced to 1,2-dihydroxynaphthalene and benzene with NH₄⁺ and HSO₃⁻ liberation. Under oxidizing atmosphere, besides the reductions of tropaeolin, water and ferric ions, the existence of a homogeneous degradation was found. This process was explained (on the basis of surface iron potential monitoring) by a stepwise reduction of oxygen giving hydrogen peroxide. The initial stages of the mechanism were similar to those under inert atmosphere, but the degradation of the 1,2-dihydroxynaphthalene continued giving 1,2-naphthalenedione, then various polar monocyclic compounds leading to three unidentified volatile final products.     

The aqueous degradation of bisphenol A and steroid estrogens by ferrate

The aqueous reactivity of five prominent endocrine disrupting chemicals (EDCs) with potassium ferrate has been studied. The degradation kinetics and reaction pathways for bisphenol A (BPA) have been considered in detail, and the reaction rate constants for 17alpha-ethynylestradiol (EE2), estrone (E1), beta-estradiol (E2), and estriol (E3) have been determined, from tests carried out in the pH range of 8-12 and at different reactant molar ratios. The rate constants were determined by a kinetic model incorporating the various species equilibria for the EDC compounds and ferrate, using observations of the temporal reduction in EDC and ferrate concentrations. In agreement with other studies, the oxidation of the EDCs was found to be greater for mono-protonated ferrate, HFeO(4)(-), than for non-protonated ferrate, FeO(4)(2-). Among the five EDCs, all of which have phenol moieties, the ferrate oxidation of the four steroid estrogens (each incorporating the cyclopentanoperhydrophenanthrene ring) had higher reaction rates than BPA. The by-products of BPA degradation by ferrate were analyzed by liquid chromatography/mass spectrometry-mass spectrometry (LC/MS-MS) and gas chromatography/mass spectrometry-mass spectrometry (GC/MS-MS) and nine specific compounds were identified, including p-isopropylphenol, 4-isopropanolphenol, p-isopropenylphenol, and some dicarboxylic acids, etc. It is concluded that ferrate oxidation could be an effective treatment method for the purification of waters containing these particular EDCs.     

Enhanced dissipation of phenanthrene and pyrene in spiked soils by combined plants cultivation

Polycyclic aromatic hydrocarbons (PAHs), a class of POPs, are widely distributed in the environment. Phytoremediation has long been recognized as a cost-effective method for removal of PAHs pollutants from soil. This study was conducted to investigate the capability of three plant species separately and their combination to promote the degradation of phenanthrene and pyrene in soil. The performance of three plant species, maize, ryegrass and white clover for phenanthrene and pyrene removal was also compared. The result showed that the presence of vegetation significantly enhances the dissipation of phenanthrene and pyrene in the soil environment. This effect was especially marked with maize. At the end of 60 days treatment, phenanthrene and pyrene concentrations in treated soils declined from an initial 52.52 mg kg-1 and 58.19 mg kg-1 to 4.15 mg kg-1 and 6.77 mg kg-1, respectively, indicating that phenanthrene and pyrene was successfully removed by maize. Around 92.10% of phenanthrene and 88.36% of pyrene were removed from soils planted with maize. Within approximately two months experimental period, the dissipation extent showed that the 4-ring pyrene was more recalcitrant than 3-ring phenanthrene. Although the extents did not differ significantly among three tested species, the rates of degradation were different. The maize treatment had the highest rate of contaminant removal after two months, followed by white clover and annual ryegrass. As compare to single plant cultivation, combined plants cultivation significantly enhanced the destruction rate and extent of phenanthrene and pyrene in soils. Around 98.22% of phenanthrene and 95.81% of pyrene were removed from soils planted with maize and ryegrass. This research indicates the potential for phenanthrene and pyrene mineralization in combined plants cultivation, which may be especially useful for phytoremediation of soils contaminated with PAHs.     

铁粉类FENTON降解对硝基苯酚的研究

以硝基苯酚(PNP)为研究对象,分析了铁粉类FENTON体系降解硝基类有机物的反应参数,结果表明对于初始浓度为100 mg/L的PNP溶液最佳降解工艺条件是pH=3±0.1,30%的H2O2投加量为2 mL/L,铁粉投加量4.0 g/L,20 min的PNP去除率达95%以上。