氮掺杂TiO2可见光光催化剂的制备及性能

以尿素和钛酸丁酯为原料,通过溶胶-凝胶法低温下制备了高可见光催化活性的氮掺杂TiO2(NDT)光催化剂,采用XRD、TEM、BET和UV-Vis DRS等测试手段对其进行了表征,并在自制光催化反应器中降解甲基橙评价了样品的光催化活性。结果表明,当氮与钛的摩尔比为0.5∶1时,350℃焙烧的样品(NDT350)具有最佳的可见光光谱吸收和光催化活性,该催化剂为锐钛矿晶相,平均粒径为21 nm,比表面积为89.13 m2/g。可见光辐照下,NDT350降解甲基橙的表观反应速率常数为1.381×10-2min-1,是商业P25催化剂的16.85倍。NDT350优良的可见光催化活性与其大的比表面积和强烈的可见光光谱吸收有关。     

磁性海泡石吸附Cr(VI)特性及动力学

采用化学共沉淀法合成磁性海泡石,通过静态吸附实验研究磁性海泡石对Cr(Ⅵ)的吸附特性及其动力学。结果表明,磁性海泡石对Cr(Ⅵ)的吸附在90 min内即可达到平衡;体系的初始pH是影响磁性海泡石吸附Cr(Ⅵ)性能的重要因素;当废水中Cr(Ⅵ)的初始浓度为50 mg/L时,磁性海泡石的适宜投加量为10 g/L;随反应温度的升高,磁性海泡石对Cr(Ⅵ)的吸附量增加;温度为25、35和45℃时,磁性海泡石对Cr(Ⅵ)的饱和吸附量分别为3.32、3.72、4.08 mg/g;吸附动力学曲线可以用拟二级反应动力学模型拟合;内扩散和液膜扩散联合控制Cr(Ⅵ)在磁性海泡石上的吸附过程,其中内扩散的控速作用大于液膜扩散。     

脂肽类生物表面活性剂液体发酵条件的响应面优化

通过Plackett-Burman和Box-Behnken实验对解淀粉芽孢杆菌XZ-173液体发酵生产表面活性素进行了响应面优化研究。首先使用Plackett-Burman实验对影响表面活性素产量的17个因素进行显著性筛选,结果表明,MnSO4、CuSO4、温度和转速为显著性因素。再运用Box-Behnken实验对这4个显著因素的取值进一步优化,得到各因素优化后的数值分别为4.4 mg/L(MnSO4)、0.18 mg/L(CuSO4)、29℃(温度)和163 r/min(转速)。响应面分析结果表明:该菌株产生表面活性素的最佳培养基为:葡萄糖15 g/L,蛋白胨5 g/L,L-谷氨酸钠6 g/L,KH2PO40.8 g/L,MgSO40.4 g/L,KCl 0.4 g/L,酵母提取物3 g/L,L-苯丙氨酸2.5 mg/L,MnSO44.4 mg/L,CuSO40.18 mg/L,FeSO40.12 mg/L;最适培养条件:pH 7.5,温度29℃,转速163 r/min,接种量5%,装液量50 mL/250 mL,摇床培养36 h。在优化后的条件下,表面活性素实际产量为336 mg/L,实际实验结果与模型预测结果相一致。表面活性素采用HPLC技术分离,发现其在浓度仅为50 mg/L时EI24就可达到70%以上,反映了表面活性素优异的乳化活性以及广阔的应用前景。     

电解锰渣中锰的浸出条件及特征

采用水洗-酸解法回收电解锰渣中锰,探讨了清水量、酸量以及温度在不同阶段对锰浸(洗)出条件的影响,分析了回收锰的主要因素及浸出特征。实验结果表明,50 g电解锰渣经m渣∶m水=1∶10的清水水洗后,采用10%的硫酸在70℃的水浴温度下酸解2 h,Mn2+浸出量为1.673 g,回收率达到97.3%,而温度和酸度对锰离子的浸出影响明显,酸度调控可有效分离酸浸锰液中金属成分,为减少电解锰渣环境污染的同时,实现电解锰渣资源化利用。     

有机酸土柱淋洗法修复重金属污染土壤

通过室内模拟实验,采用土柱淋洗方法,研究草酸、柠檬酸、乙酸和酒石酸溶液对某电镀厂附近土壤中重金属的去除效果。探讨了淋洗剂浓度、淋洗次数和淋洗时间等对淋洗效果的影响,研究草酸淋洗前后土壤中重金属形态的变化。结果表明,淋洗过程中铬的去除效果明显滞后于铜、锌和镍3种重金属离子。1 mol/L的草酸在土水比为1∶1,淋洗5h,淋洗4次的条件下可以达到最佳淋洗效果,Cu、Zn、Ni和Cr的去除率分别是99.6%、66.98%、88.7%和18.23%。     

进水水质成分改变引发的污泥粘性膨胀及控制

在研究强化SBR工艺除污性能时,由于可溶性淀粉投加导致进水水质成分发生改变,污泥沉降性能在短时间内迅速恶化,污泥出现大量的粘液。镜检发现,大量指状菌胶团异常增殖且丝状菌的数量也逐渐减少。实验结果表明,系统膨胀属于污泥粘性膨胀。停止可溶性淀粉和提高主反应池的DO浓度,污泥粘性膨胀并未得到恢复,但污泥粘液逐渐消失。粘液消失后,通过模拟前期进水水质成分和缩短泥龄,污泥粘性膨胀得以控制,污泥沉降性能在短时间内恢复。实验还研究了污泥粘性膨胀对污染物去除性能的影响。     

Biological monitoring of environmental exposure to polycyclic aromatic hydrocarbons in subjects living in the area of recycling electronic garbage,in Southern China

The study was undertaken to evaluate the environmental exposure to polycyclic aromatic hydrocarbons in subjects living in the area of recycling electronic garbage in Southern China and research the influence of environment smoke tobacco (EST) to people through active and passive smoking. Urinary concentrations of 2-hydroxynaphthalene, 2-hydoxyfluorene, 9-hydroxyphenanthrene, and 1-hydroxypyrene were determined in 141 randomly selected voluntary residents aged 13 to 81 years in two polycyclic aromatic hydrocarbon (PAH)-exposed groups, two control groups, and an EST research group. The concentrations of 2-hydroxynaphthalene, 2-hydoxyfluorene, 9-hydroxyphenanthrene, and 1-hydroxypyrene in PAH-exposed groups are significantly higher (p?PAHs (PAHm) are significantly elevated through active and passive smoking, while the influence of EST to other PAHm is not statistically significant. 2-Hydroxynaphthalene, 2-hydoxyfluorene, 9-hydroxyphenanthrene, and 1-hydroxypyrene in the urine of smokers are, respectively, 3.9, 1.9, 1.4, and 1.9 times to those of nonsmokers. In nonsmokers, passive smokers excreted 1.1, 1.5, 1.9, and 1.5 times of 2-hydroxynaphthalene, 2-hydoxyfluorene, 9-hydroxyphenanthrene, and 1-hydroxypyrene compared to nonpassive smokers.     

Radiation modeling of a photo-reactor using a backward ray-tracing method: an insight into indoor photocatalytic oxidation

This article aims to understand the radiation behavior within a photo-reactor, following the ISO 22197-1:2007 standard. The RADIANCE lighting simulation tool, based on the backward ray-tracing modeling method, is employed for a numerical computation of the radiation field. The reflection of the glass cover in the photo-reactor and the test sample influence the amount of irradiance received by the test-sample surface in the photo-reactor setup. The reflection of a white sample limits the irradiance reduction by the glass cover to 1.4 %, but darker samples can lead to an overestimation up to 9.8 % when used in the same setup. This overestimation could introduce considerable error into the interpretation of experiments. Furthermore, this method demonstrates that the kinetics for indoor photocatalytic pollutant degradation can be refined through radiation modeling of the reactor setup. In addition, RADIANCE may aid in future modeling of the more complex indoor environment where radiation affects significantly photocatalytic activity.     

不同运行模式对同步脱氮除磷CAST工艺快速启动及其稳定维持的影响

以实际生活污水为处理对象,考察了传统进水/曝气和改良型分段进水的交替缺氧-好氧(A/O)2种运行模式对CAST工艺的快速启动及脱氮除磷性能稳定维持的影响。结果表明,传统进水/曝气运行模式下,系统达到最佳营养物去除性能所需启动时间30 d,稳定运行阶段TN平均去除80.66%,磷的去除率维持在66.30%左右;采用改良型交替运行模式,反应器达到稳定运行状态仅需18 d,系统稳定运行时TN平均去除81.36%,磷去除率稳定维持在90%以上,出水磷浓度在0.3 mg/L以下,出水水质达到国家污水综合排放标准一级A(GB8978-2002)。研究还发现,传统运行模式下,由低温引起的污泥沉降性能变差导致系统污泥严重流失,反应器几乎丧失污染物去除性能;而低温对交替运行模式下的反应器除磷性能几乎没有影响,总氮去除则因氨氮不完全硝化而大大降低。     

Recycling and pollution control of the End of Life Vehicles in China

The quantity of vehicles has increased rapidly in recent years in China; however, the recycling of End of Life Vehicles (ELV) faces several problems and barriers including the collection difficulty and the environmental pollution caused by improper dismantling. In this paper, based on analysis of the basic situation regarding management and recycling of ELV in China, the ELV flow was introduced, and the potential ELV quantity was estimated. The current management regulations and policies were summarized, and dismantling and pollution control technologies for ELV recycling were introduced, too. It was suggested that with the rapid growth of ELV quantities, more regulations will be enacted, and the recycling network will be more effective; the dismantling technology and pollution control measures will be upgraded, and the recycling and remanufacturing industries will be more combined. The government should pay more attention to improve the management and supervision of, and encourage the development of, high level enterprises.