纳米SiO2对含十二烷基苯磺酸钠微污染原水的助凝特性

以含微污染有机物——十二烷基苯磺酸钠(SDBS)的高岭土悬浊液为研究对象,投加聚合氯化铝(PAC)与纳米SiO₂,借助在线显微摄像技术与分形理论,探讨了纳米SiO₂作为水处理剂的絮凝作用、助凝效果以及形态学特性.结果表明:①PAC与纳米SiO₂单独使用时,PAC对无机高岭土颗粒去除效果好;而纳米SiO₂对去除SDBS有利. ②仅投加PAC,当pH为10时,SDBS去除率低于4%;当pH为5～6时,SDBS去除率可达50%. ③不同pH下将纳米SiO₂与PAC联用,SDBS去除率显著提高;以纳米SiO₂为助凝剂,偏酸性环境有利于SDBS的去除,当pH为5时,SDBS去除率可达75%.④中性条件下,在PAC与纳米SiO₂投加量比值为3时,纳米SiO₂的助凝效果最优;纳米SiO₂宜在投加PAC后40 s时加入,絮体粒径大、结构强大、沉降性能好、分形维数值大、剩余浊度低,SDBS去除率高.      

海藻酸钠/β-环糊精固定化纳米Fe~0去除重金属的性能研究

针对纳米Fe0在空气中易被氧化的问题,应用海藻酸钠、β-环糊精对纳米Fe0进行协同固定化,考察了原料配比、交联剂浓度等对凝胶球性能的影响,并对固定化纳米Fe0材料的稳定性进行了考察。实验结果表明:以1.5%SA、0.5%β-CD为原料,4.0%Ca Cl2为交联剂制备的固定化纳米Fe0具有较高的反应活性;固定化Fe0对Pb2+的去除效率明显高于Cd2+,反应4 h,200 mg/L的Pb2+去除率可达99.3%,主要通过凝胶球与Fe0联合作用去除。该材料保存120 d后仍具有较高的反应活性。     

TiO2/ZSM-5m光催化耦合过硫酸盐降解焦化尾水的研究

以具有介孔结构的沸石分子筛ZSM-5m负载纳米TiO2制备出复合型光催化剂,用扫描电镜、比表面及孔径分析仪和X射线衍射对形貌和结构进行表征,通过序批试验考察了TiO2/ZSM-5m/过硫酸盐体系深度降解焦化生化处理出水中残余有机污染物(ROPs)的效果和机理.结果表明,在COD初始平均浓度为352mg/L,TiO2/ ZSM-5m投加量为1.6g/L,pH值为3.0,C(Na2S2O8)为0.8g/L,常温下反应180min,COD出水平均浓度为76.3mg/L,去除率达到78.2 %,在上述优化条件下可达到现行污染物排放标准.ROPs光催化符合Langmuir-Hinshelwood模型,推测具有微介双孔结构的催化剂表面电子易被S2O82-俘获,降低空穴与电子的复合率,促进了·OH 和SO4-·形成,对ROPs的吸附和光降解有较大的强化作用.用GC-MS对处理前后废水中的污染物进行测定以揭示降解与转化规律,发现苯类特征污染物能有效降解,但产生的中间产物明显增多.     

Effects of arsenic exposure during early postnatal period on Leydig cells of rat testis

The effects of sodium arsenite exposure from postnatal day (PND) 1 to PND 14 on Leydig cells of Wistar rat testes were investigated at PND 15 and 21. Gross morphometric observations of testes did not reveal a significant change in the numerical density and volume of the testes in exposed animals compared to controls either at PND 15 or 21. However, there was significant decrease in testicular weight at PND 21 in treated animals. Measurement of nuclear area of Leydig cells revealed a decrease in nuclear area of these cells in exposed groups at PND 15 and 21. A significant decrease in the total number of Leydig cells was apparent at PND 21 in the treated group. The observations of the present study are indicative of adverse effects on rat testes Leydig cells following exposure to low doses of sodium arsenite during critical window periods. The persistence of these observations at PND 21 is suggestive of irreversible damage to testicular tissue.     

Protective effects of quercetin against sodium fluoride-induced oxidative stress in rat erythrocytes

Protective effects of quercetin against oxidative stress induced by sodium fluoride intoxication in rat erythrocytes were evaluated. Rats were divided into five groups consisting of 10 in each for this experiment. The animals of group I received water and standard diet to serve as control group, the animals of groups II and III were treated with quercetin (10 and 20?mg?kg^?1 body weight), administrated intraperitoneally for 7 days followed by sodium fluoride (600?ppm) in drinking water for the next 7 days. The animals of group IV were treated with vitamin C (10?mg?kg^?1) intraperitoneally for 7 days followed by sodium fluoride treatment for next 7 days serving as positive control group. The animals of group V were treated only with sodium fluoride (600?ppm) for the same time and were used as control group. Blood sample were collected via retro-orbital puncture. The antioxidant enzymes, superoxide dismutase, and catalase, as well as the levels of reduced glutathione and lipid peroxidation end products were measured in erythrocytes. There was a significant increase in lipid peroxidation along with a decrease in superoxide dismutase activity in the erythrocytes of sodium fluoride-treated animals. Quercetin treatment prior to fluoride administration normalized the levels of all parameters measured in the rat erythrocytes.     

海藻酸钠对改性黏土絮凝特征的影响

以海藻酸钠为藻源有机质的模式化合物,考察了赤潮水体中藻源有机化合物对改性黏土絮凝速率及絮凝体特征的影响;并利用图像分析法,测定了絮凝体的分形维数Df,借助分形维数对改性黏土的絮凝形态学特征进行了半定量化分析.结果表明:当海藻酸钠浓度在10~100mg/L范围内时,可以提高改性黏土絮凝的速率,絮凝体的分形维数Df、絮凝体强度呈现出先增大后减小的规律;其中,最佳浓度为50mg/L,其最大絮凝速率达到44.13、Df 为1.6823.低浓度(100mg/L)海藻酸钠能促进改性黏土的絮凝效率,但促进作用呈现减小的趋势,表现为最大絮凝效率减小,Df降低、絮凝体的空隙率增大.     

微量滴定法测定微痕量铀的研究及应用

在磷酸介质中,试样经硫酸亚铁铵、亚硝酸钠、尿素预处理后,铀为4价,以二苯基联苯胺二磺酸钠为指示剂,用标准钒酸铵滴定至微红色,实现了不经分离与富集直接测定。ｎ×10－5g／g以上的痕量铀的微量滴定分析。方法简便、快速、廉价,环境污染少。     

催化还原脱除地下水中硝酸盐的研究

采用浸渍法制备催化剂Pd-Cu/γ-Al2O3,用BET、ICP、XRD、TEM和EDX对该催化剂进行了表征.以甲酸钠作为还原剂,对催化还原硝酸盐进行了试验研究.结果表明,100 mg·L-1硝酸盐完全反应时总氮的脱除率可以达到87%.催化反应的活性和选择性受pH值、催化剂投加量、甲酸钠浓度和硝酸盐初始浓度等反应条件影响.甲酸钠作为还原剂时只需控制溶液初始pH值,初始pH值过高或过低都会降低催化剂活性;控制初始pH值为4.5,适当降低催化剂投加量和增加甲酸钠的浓度有利于提高催化活性,但选择性会显著降低.初始pH值为4.5时,不同初始浓度硝酸盐的催化还原反应为一级反应.     

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。     

从废蚀刻液中回收资源的应用研究

从电路板蚀刻液回收硫酸铜及制作再生蚀刻液进行了工艺探索 ,得出中和法可从蚀刻液中脱除约 90 %的铜 ,沉淀氢氧化铜的最佳pH值为 5 6～ 6 0。采用水合肼还原法与硫化钠沉淀法可进一步脱除蚀刻液中的铜。研究结果表明 ,水合肼还原法回收海绵铜 ,在pH值为 6 0 ,反应温度 4 0℃ ,水合肼的投加浓度为 3%时 ,铜的回收率达到了 98%以上。而硫化钠沉淀法可取得 99%以上脱除废液中的铜效果 ,且具有适应范围广 ,操作成本低的优势。进一步除铜后的废液可回用于制新蚀刻液