混凝和强化混凝对印染废水中锑(Ⅴ)的去除特性

印染废水中锑的排放标准日趋严格,是印染废水处理面临的新挑战.以混凝和强化混凝去除印染废水中锑(Ⅴ)为目标,发现聚硫酸铁(PFS)混凝剂对印染废水中锑(Ⅴ)的去除效率显著优于铁铝复配混凝剂和铝盐混凝剂,去除效率达97.4%,出水锑(Ⅴ)浓度可达4μg·L~(-1).酸性条件(低水解度)有利于PFS生成Fe(a)活性组分和静电吸引、锑(Ⅴ)迁移,且絮体颗粒较小,促进PFS混凝除锑(Ⅴ)效率;酸性条件下PFS除锑(Ⅴ)效率是中性条件的1.27倍,处理出水中锑(Ⅴ)浓度仅为中性条件的33.3%.PFS投加量与除锑(Ⅴ)效率符合反比例模型.在较高锑(Ⅴ)浓度下,提升PFS投加量可提高除锑(Ⅴ)效率,但在较低锑(Ⅴ)浓度下,提升PFS投加量对除锑(Ⅴ)效率的促进较小.PFS絮体回流与混凝沉淀串联或耦合可显著提升印染废水中锑(Ⅴ)的去除效率,其除锑(Ⅴ)效率分别是单一PFS混凝沉淀的1.14倍和1.32倍,可有效降低出水锑(Ⅴ)浓度并节约PFS投加量和减少污泥生成量.其中混凝-絮体回流耦合工艺中,最佳絮体回流比例为100%.     

三聚磷酸钠在层状氢氧化镁铝及其焙烧产物上的吸附特性

通过静态吸附实验,研究了水溶液中三聚磷酸钠(STPP)在层状氢氧化镁铝(Mg-Al LDH)及其焙烧产物(Mg-Al CLDH)上的吸附性能,并用多晶X射线衍射对Mg-Al LDH,Mg-Al CLDH及Mg-Al CLDH吸附STPP后Mg-Al RLDH的结构进行了表征.结果表明,STPP在层状氢氧化镁铝及其焙烧产物上的吸附量和脱除率在pH为4.7-10.0时受溶液初始pH值的影响较小;饱和吸附量随温度的升高而增大,在25-50℃下,STPP在层状氢氧化镁铝上的饱和吸附量为34.52-40.20 mgP3 O105-·g-1,在25-60℃下,STPP在焙烧层状氢氧化镁铝上的饱和吸附量为118.67-179.57mgP3O105-·g-1.静态吸附热力学结果证明STPP在层状氢氧化镁铝及其焙烧产物上的吸附为自发的物理吸热过程,焓变与熵增是吸附的主要驱动力.     

氢氧化镁在环境污染治理中的应用研究进展

本文综述了不同种类氢氧化镁工业产品的特性及其在废水处理、烟气脱硫等方面的应用进展 ,并讨论了在我国的应用趋势     

UV强化草酸络合Fe3+活化过硫酸盐氧化降解苯胺

采用UV-草酸络合Fe~(3+)[UV-Fe(C_2O_4)3-3]活化过硫酸钠(PS)氧化降解苯胺,研究了Fe(C_2O_4)3-3浓度,PS浓度,pH对PS活化效率及苯胺氧化降解效果的影响机制.结果表明,Fe(C_2O_4)3-3浓度和pH决定了UV-Fe(C_2O_4)3-3体系中Fe~(3+)向Fe2+的转化过程,并对活化PS氧化降解苯胺产生显著影响.随着Fe(C_2O_4)3-3浓度增加,PS的分解率不断提高,但当浓度高于0.75 mmol·L~(-1)时,草酸根离子(C2O_2-4)对硫酸根自由基(SO·-4)的竞争以及SO·-4之间的相互淬灭作用降低了苯胺的降解效果,降解速率大小顺序为5 mmol·L~(-1)0.25 mmol·L~(-1)0.5 mmol·L~(-1)1 mmol·L~(-1)0.75 mmol·L~(-1);中性和碱性条件不利于Fe(C_2O_4)3-3发生光化学反应生成Fe2+,但当初始pH为7和9时,由于PS活化分解过程降低反应体系pH,反应300min时PS的活化率可分别达到74%和67%,苯胺去除率分别高达91%和97%,均高于初始pH为酸性条件下的结果;苯胺降解率随初始PS浓度增加而增大,当PS浓度大于10 mmol·L~(-1)时,苯胺降解过程由二级反应变为准一级反应,但此时过量的PS因与SO·-4发生反应而显著降低PS用于氧化降解苯胺的利用率.     

含铅废水絮凝处理的试验研究

正交法确定了含铅废水絮凝过程中聚合磷硫酸铁的较佳用量、pH值、沉淀时间和原水Pb2+的控制浓度。实验结果表明,聚合磷硫酸铁对含铅废水处理效果明显,处理后排水中的残留磷量和残留铁量较少,低于国家排放标准,不存在铁、磷的二次污染。     

Characterization of the lignin signature in Lake Mead,NV, sediment: comparison of on-line flash chemopyrolysis (600°C) and off-line chemolysis (250°C)

The distribution of lignin in sediment is a useful tool for tracing the transport of land-derived organic matter in an aquatic environment. Tetramethylammonium hydroxide (TMAH) flash chemopyrolysis, or chemolysis followed by GC–MS analysis can be used for evaluating the origin of organic carbon in sediments. TMAH chemopyrolysis or chemolysis of organic matter produces a myriad of semi-volatile products. Among these products are methylated phenols which are an indirect measure of lignin in sediment. In this study, total organic carbon, elemental carbon, and lignin were measured in Lake Mead sediments. This study indicates that terrestrial runoff makes a contribution to Lake Mead sediments, and that this contribution is most apparent in sediment that is close to the Las Vegas Wash. Two chemolysis methods (on-line and off-line) were examined and compared for detection of lignin phenols. The results from these sediment cores indicate that comparable results can be obtained from the two approaches, although detection levels are significantly lower for the off-line approach.     

用聚硅酸铁铝混凝剂处理炼油厂废水

研究了以煤矸石和硫酸烧来主要原料研制的聚硅酸铁铝（ＰＳＦＡ）混凝剂对炼油厂废水的絮凝作用及混凝剂种类、用量和体系ＰＨ对混凝效果的影响,试验结果表明,在工ＰＨ范围内,ＰＳＦＡ对炼油废水具有良好的混凝处理效果。与传统混产剂相比,它具有破乳性能好、投量少、滤饼含水率低、上清液透光性好的特点。     

含硼聚硅硫酸铁絮凝剂的制备及其絮凝性能

以硅酸钠、硫酸铁和四硼酸钠为原料,在SiO2质量分数为3％、pH为3．0、活化时间为30min铁与硅摩尔比为0.5、硼与硅摩尔比为0.31的条件下,制备了无机高分子絮凝剂——含硼聚硅硫酸铁（PFSSB）。当焦化厂生化后废水pH在6.0左右、PFSSB加入量为20mg／L时,除浊率和脱色率分别达到93％和60％以上。PFSSB的脱色、除浊性能明显优于聚合氯化铝。     

Phenolic content,antioxidant and antibacterial activity of selected natural sweeteners available on the Polish market

Seventeen natural sweeteners available on the Polish market were screened for total phenolic content, by the Folin-Ciocalteu method, and for antioxidant activity, using the ferric reducing antioxidant power (FRAP) assay and the 2,2′-Azinobis (3-ethylbenzthiazoline-6-sulphonic acid) radical cation decolorization assay (ABTS^·+). In addition, we analyzed antibacterial activities against Staphylococcus aureus strains: both those susceptible and those resistant to methicillin (MRSA). The results of the study showed that total phenolic content, antioxidant activity and antibacterial activity differ widely among different samples of sweeteners. Phenolic content, expressed as a gallic acid equivalent, ranged from 0 mg kg^?1 in white, refined sugar, xylitol and wheat malt syrup to 11.4 g kg^?1 in sugarcane molasses. Antioxidant activity was lowest in refined white sugar, xylitol, brown beet sugar, liquid fructose, and rape honey; it was average in spelt syrup and corn syrup, and highest in sugar cane, beet molasses, date and barley syrups. Despite the great variety of sweeteners, a strong correlation was noted between the concentration of phenolics and antioxidant properties, as determined by the ABTS^·+ method (r = 0.97) and the FRAP assay (r = 0.77). The strongest antibacterial activity was observed in sugarcane molasses, which was lethal to S. aureus strains at 2 and 4% concentrations in medium for susceptible and MRSA strains respectively. Other sweeteners kill bacteria in 6–15% solutions, whereas some did not show any antibacterial activities against S. aureus strains, even at 20% concentrations. Due to their high antioxidant and antibacterial activities, some of the tested sweeteners have potential therapeutic value as supporting agents in antibiotic therapy.     

用透射电镜研究聚硅酸硫酸铁混凝剂的形态

由水玻璃、硫酸和硫酸铁制备聚硅酸硫酸铁（ＰＦＳＳ）混凝剂,用透射电镜观察ＰＦＳＳ的形态,研究了ＰＦＳＳ的形态随硅酸聚合时间,ＳｉＯ２／Ｆｅ摩尔比和熟化时间的变化。结果表明,硅酸聚合时间,ＳｉＯ２／Ｆｅ摩尔比及熟化时间对ＰＦＳＳ的形态有较大的影响。