LiFePO_4非均相Fenton法处理亚甲基蓝染料的研究

采用水热法制备出LiFePO4催化剂,通过电子显微镜（SEM）、X射线衍射（XRD）和傅立叶红外光谱（FTIR）对其进行表征,并将其作为非均相Fenton催化剂处理亚甲基蓝（MB）染料溶液。实验结果表明,在催化剂用量为4 g/L,H2O2浓度为0.04 mol/L,pH值为3,温度为50℃,反应时间为60 min的条件下,浓度为500 mg/L的亚甲基蓝脱色率达99%。根据实验结果,讨论了LiFePO4作为非均相Fenton催化剂对亚甲基蓝的降解机理。     

Relevant parameters for assessing the environmental impact of some pyridinium, ammonium and pyrrolidinium based ionic liquids

Several physico-chemical properties relevant to determine the environmental impact of ionic liquids - aqueous solubility, octanol/water partition coefficient, chromatographically derived lipophilicity and infinite dilution diffusion coefficients in water - were measured in ionic liquids based on pyridinium, ammonium and pyrrolidinium cations with bis(trifluoromethylsulfonyl)imide anions. The influence of the presence of hydroxyl or ester groups in the physico-chemical properties of these liquids was checked. It appeared that the presence of functional oxygenated moieties reduces the lipophilicity of ionic liquids and so decreases the risk of bioaccumulation in environment.     

A2O氧化沟缺氧区三维流场模拟及结构形式优化

以FLUENT软件为工具,选用三维RNG k-ε紊流数学模型对重庆井口污水厂A²O氧化沟缺氧区内的流场进行模拟,分析了缺氧区内流场分布不均匀及沉泥的原因,提出了水下推进器的合理设置位置与导流墙的合理设置方式,并对优化后的缺氧区进行了模拟计算。通过优化后模拟的结果可见,在相同的功率密度下,缺氧区内的流场得到了较均匀的分布,流速从原来的0.131 m/s提升到0.204 m/s,减少了能量的损失。底部的流速也从原来的0.140 m/s提升到0.226 m/s,有效的防止或减少了沟中的污泥沉积。优化的结果对实际工程的设计也有一定的指导意义。     

生物表面活性剂在城市污泥静态强制通风好氧堆肥中的作用

采用静态强制通风好氧堆肥模式对城市剩余污泥进行堆肥降解,并研究了生物表面活性剂鼠李糖脂对堆肥过程的作用。结果表明,堆肥过程中,添加了质量分数为0.015%鼠李糖脂溶液堆制处理和空白对照堆制处理的堆温变化都明显呈现出中温期0～5 d、高温期6～12 d和降温期13～28 d 3个阶段。实验组比空白组的堆体升温快、高温期持续时间长、堆体的含水率高。鼠李糖脂的添加,使实验组的微生物数量高于空白组。添加鼠李糖脂的堆体和空白堆体的种子发芽指数(GI)在堆肥结束时分别为53.70%和50.80%,说明鼠李糖脂促进了堆肥的腐熟,但由于相对浓缩效应,堆肥产品的重金属含量略高于空白堆体。生物表面活性剂的介入促进了堆肥中木质纤维素的初步降解。研究表明,添加鼠李糖脂能够改善堆肥处理的微环境,促进有机质降解和堆肥的腐熟。     

侧沟式一体化OCO工艺中DO和C/N对同步硝化反硝化的影响

以自配模拟生活污水为处理对象,研究了不同DO和C/N对侧沟式一体化OCO反应器同步硝化反硝化和COD降解效果的影响。实验结果表明,维持进水COD均值约为300 mg/L,TN约为40 mg/L,MLSS约为2 600 mg/L,进水流量为20 L/h时,COD去除率随着DO的增大逐步提高,当好氧区DO均值约为2.0 mg/L时,同步硝化反硝化效果最好,TN去除率达到了80%以上;维持好氧区DO均值约为2.0 mg/L,MLSS约为2 600 mg/L,进水流量为20 L/h时,不同C/N对COD去除率影响不大,当进水C/N约为8时,同时硝化反硝化效果最好,TN去除率均值达到了82%。     

改性多壁碳纳米管对水中Cd2+的去除

为了增加多壁碳纳米管(multiwall carbon nanotubers,MWNTs)对水中Cd2+的吸附量,使用混酸对多壁碳纳米管进行氧化处理,采用红外光谱进行结果表征,并探讨了吸附时间、pH值和MWNTs的使用量、Cd2+的浓度及干扰离子对镉离子吸附的影响。结果表明,吸附时间为1.5 h、pH为5.3、吸附效果最佳,随MWNTs量的增加Cd2+去除量增加,共存的阳离子会降低对Cd2+的吸附效果,对Cd2+的吸附符合Longmuir吸附定律。研究同时表明,pH小于2时Cd2+能容易从碳纳米管上解吸。初步探讨了Cd2+吸附机制。     

环糊精在环境治理中的应用研究进展

环糊精及其衍生物由于具有一定大小的低极性空腔结构,能够包合多种低极性有机物,形成主客体包合物.这种包合物的形成可以增加有机物的水溶性和促进其被微生物的分解利用;可以改变有机物的物理化学特性,促进其在光化学和芬顿体系中的降解;可以在去除有机物的同时,去除Cd2 等无机物;此外,环糊精还可以用来制成环境友好材料,吸除空气和水中污染物.     

高铁酸钾降解苯酚的机制研究

借助高效液相色谱(HPLC),通过标准物比对法和添加标准物法,研究了高铁酸钾降解苯酚的开环产物.结果表明,高铁酸钾降解苯酚的主要稳定的中间产物有顺丁烯二酸、反丁烯二酸、草酸和甲酸.并据此推导出苯酚被高铁酸钾氧化降解的可能途径.     

Photodegradation of bisphenol Z by UV irradiation in the presence of beta-cyclodextrin

In this work, the formation of the inclusion complex of bisphenol Z (1,1-bis(4-hydroxyphenyl)cyclohexane, abbreviated as BPCH) with beta-cyclodextrin (beta-CD) has been studied, 1:1 inclusion complex can be obtained, the formation constant of the beta-CD/BPCH complex is 5.94x10(3)M(-1). The photodegradation behavior of BPCH was investigated under monochromatic UV irradiation (lambda=254 nm). The photodegradation rate constant of BPCH in aqueous solutions with beta-CD showed a 9.0-fold increase, and simultaneously the mineralization of BPCH can be enhanced by beta-CD. The influence factors on photodegradation of BPCH were also studied and described in details, such as concentration of beta-CD, initial concentration of BPCH, organic solvent and pH. The photodegradation of BPCH in the presence of beta-CD includes the direct photolysis and the photooxidation of BPCH during the photochemical process. Some predominant photodegradation products are 4-(2,4,5-trihydroxy-phenyl)-4-(4-hydroxyphenyl) butanoic acid, 5,5-bis(4-hydroxyphenyl)pentanoic acid, meta-hydroxylated BPCH, ortho-hydroxylated BPCH and 4-(1-(4-hydroxyphenyl)pentyl)phenol respectively. The enhancement of photodegradation of BPCH mainly results from moderate inclusion depth of BPCH molecule in the beta-CD cavity. This kind of inclusion structure allows BPCH molecule sufficient proximity to secondary hydroxyl groups of the beta-CD cavity, and these hydroxyl groups could be activated and converted to hydroxyl radicals under UV irradiation, which can enhance the photooxidation of BPCH.     

Rapid quantification of polycyclic aromatic hydrocarbons in hydroxypropyl-beta-cyclodextrin (HPCD) soil extracts by synchronous fluorescence spectroscopy (SFS)

Synchronous fluorescence spectroscopy (SFS) was directly applied to rapidly quantify selected polycyclic aromatic hydrocarbons (PAHs: benzo[a]pyrene and pyrene) in aqueous hydroxypropyl-beta-cyclodextrin (HPCD) soil extract solutions from a variety of aged contaminated soils containing four different PAHs. The method was optimized and validated. The results show that SFS can be used to analyse benzo[a]pyrene and pyrene in HPCD based soil extracts with high sensitivity and selectivity. The linear calibration ranges were 4.0x10(-6)-1.0x10(-3)mM for benzo[a]pyrene and 6.0x10(-6)-1.2x10(-3)mM for pyrene in 10mM HPCD aqueous solution alone. The detection limits according to the error propagation theory for benzo[a]pyrene and pyrene were 3.9x10(-6) and 5.4x10(-6)mM, respectively. A good agreement between SFS and HPLC was reached for both determinations of PAHs in HPCD alone and in soil HPCD extracts. Hence, SFS is a potential means to simplify the present non-exhaustive hydroxypropyl-beta-cyclodextrin (HPCD)-based extraction technique for the evaluation of PAH bioavailability in soil.