Co掺杂TiO2纳米晶光催化降解制浆黑液

用溶胶-凝胶法制备Co掺杂TiO2纳米晶,利用X-射线衍射(XRD)和紫外-可见光谱(UV-Vis)对样品进行表征.结果表明400℃时,粒子平均粒径为10nm左右,适量Co掺杂抑制TiO2晶粒的成长,掺Co使TiO2纳米晶的光谱响应范围向可见光拓展.在紫外光照射下,掺杂Co的TiO2能有效促进光催化降解制浆黑液,显著提高制浆黑液中CODCr的去除效果,反应8h后,CODCr由反应前的480mg/L降至144mg/L,色度去除率可达到86.9%.     

Fe3+和La3+共掺杂纳米TiO2的制备及光催化性能的研究

通过溶胶凝胶法制备掺杂铁和镧的纳米TiO2,并以活性红15为目标降解物,研究了其光催化性能.采用热失重分析(TG)、X射线衍射(XRD)、电镜、紫外-可见漫反射光谱(DRS)等测试手段对TiO2的结构、晶型、光吸收范围等进行了表征.结果表明:共掺杂的纳米TiO2在500℃煅烧3 h呈现锐钛矿型,晶粒尺寸约15 nm;掺杂铁和镧的纳米TiO2吸收带会发生红移,拓展了其对光谱响应范围.通过光催化降解模拟试验,发现掺杂铁和镧的纳米TiO2粉末对活性红15溶液的降解率最高达到98.9%,具有较高的光催化活性.     

金属共掺杂纳米TiO2对甲基橙的催化降解

以硫酸钛、CoCl2·6H2O和FeCl3为原料,采用共沉淀法制备了掺杂不同量Co2+和e3+的TiO2纳米粒,通过X-射线衍射(XRD)、差热-热重(TG-DTA)和紫外-可见吸收光谱(UV-Vis)等分析手段对样品的晶体类型、光谱吸收特征进行了表征.结果表明,金属共掺杂TiO2纳米粒仍以锐钛矿相存在,粒子的粒径约为12 nm;Co2+和Fe3+掺入TiO2后,主要以替代的方式占据TiO2晶格中Ti4+的位置,并在TiO2禁带中产生掺杂能级,使原来位于380 nm的吸收带边红移至460 nm.以太阳光为光源,当Co2+掺杂量为0.025%,Fe3+掺杂量小于0.05%时,光催化剂TiO2的活性较高,对甲基橙的降解率接近100%.     

Ni掺杂介孔TiO2的制备及其光催化降解造纸废水

采用溶胶-凝胶法合成了不同Ni掺杂量的介孔TiO2材料,用X射线衍射(XRD)、透射电子显微镜(TEM)、红外(FT-IR)和N2吸附脱附等分析技术对产物结构和组成进行了表征.结果表明,介孔骨架TiO2主要以锐钛矿存在,介孔孔径由未掺杂时的8.8 nm增加到掺杂2%后的10.6 nm,BET比表面积由未掺杂时的159 m2/g降至136 m2/g.在紫外光照射、初始pH值4、连续通氧、催化剂用量1.5 g/L的反应条件下,使用不同Ni掺杂量的TiO2作为催化剂光催化降解造纸废水.实验表明,当Ni掺杂量为2%时,造纸废水的光催化降解效果最佳.以Ni掺杂量为2%的TiO2为催化剂,光催化降解造纸废水,废水的色度和CODCr去除率分别为100%和83.4%.     

掺杂纳米TiO2棉织物的自清洁性能

采用氧化沉淀法,锌与TiO2的质量比为0.3%,制备了锌离子掺杂纳米TiO2光催化剂。掺杂纳米TiO2可使5 mg/L亚甲基蓝溶液在紫外光下达到56.75%的降解率,可见光下达到42.93%的降解率。将Zn2+/TiO2质量比为0.4%的掺杂纳米TiO2整理到棉织物上,表现出较强的自清洁性能。在紫外光或是可见光照射16 h后,棉织物上的辣椒油污渍基本完全分解。     

新型纳米TiO2的制备及其研究

以钛酸正丁酯为前驱物,采用溶胶-凝胶(Sol-Gel)法制备出了新型S-N掺杂的纳米TiO2,通过紫外可见吸收光谱、粒度测试、TEM测试、XRD光谱分析对所制备的粉体进行了性能表征,结果表明,和未掺杂样品相比,S-N共掺纳米TiO2的紫外吸收性能得到了改善,最佳的掺杂比例(S-N/Ti)为1∶1;本试验制得的S-N共掺纳米TiO2属于金红石和锐钛矿的混合晶型,具有较小的尺寸,粒径小于18nm,并且分散性能较好.     

分光光度-低压离子色谱法测定Cu2+、Ni2+、Zn2+、Pb2+、Fe2+和Mn2+

建立了分光光度-低压离子色谱法测定Cu2+、Ni2+、Zn2+、Pb2+、Fe2+和Mn2+6种重金属离子的分析方法.选用柠檬酸-草酸混合液作为洗脱体系进行梯度洗脱,将6种金属离子完全分离,柱后采用1-(2-吡啶偶氮)-2-萘酚(PAN)进行衍生反应,于波长560 nm处进行检测.6种离子的检出限分别为0.006、0.012、0.005、0.125、0.070、0.020 mg/L.该方法用于环境水样测定,结果与原子吸收法所测值基本吻合,分析结果令人满意.     

弱酸性染料的铁氮共掺杂纳米TiO_2光催化降解

以硝酸铁为铁源、尿素为氮源、钛酸四丁酯为钛源,采用溶胶-凝胶法制备铁氮共掺杂纳米TiO2光催化剂(Fe—N—TiO2)。利用X射线衍射仪(XRD)、红外光谱仪(FT-IR)和紫外-可见吸收光谱仪(UV-Vis),表征分析所制备的Fe—N—TiO2光催化剂的晶体结构和光谱性质;以弱酸性红RN染料为目标降解物,研究测试其可见光催化性能。结果表明,所制备的Fe—N—TiO2光催化剂为锐钛矿相,平均粒径为17.1 nm;其吸收边带红移至528 nm,禁带宽度为2.35 eV。在300 W金卤灯照射下,光催化反应240 min,0.12 g Fe—N—TiO2光催化剂对100mL质量浓度为5mg/L、染液初始pH值为5的弱酸性红RN染料的降解率达97.28%。     

Co掺杂ZnO微/纳米纤维的制备及其光催化性能

以聚乙烯吡咯烷酮(PVP)为络合剂,与醋酸锌(Zn(CH3COO)2)和乙酸钴(Co(CH3COO)2)反应制得前驱体溶液.采用静电纺丝法制备了PVP/Zn(CH3COO)2/Co(CH3COO)2复合微/纳米纤维,经过高温煅烧得到Co掺杂ZnO微/纳米纤维.采用热重分析(TG)、X射线衍射(XRD)、扫描电镜(SEM)等手段对其进行了表征.以甲基橙模拟有机污染物,考察紫外光照射下所得Co掺杂ZnO微/纳米纤维的降解效果.实验结果表明,所制备的Co掺杂ZnO微纳米纤维对甲基橙溶液具有良好的光催化性能,在光照80min后降解率可达93%.     

氮铈共掺杂介孔TiO2的制备及在造纸废水处理中的应用

以钛酸四正丁酯为前躯体,用聚氧乙烯脂肪醇醚(Brij98)和十六烷基三甲基溴化铵(CTAB)作为复合模板剂,硝酸铈和尿素为掺杂离子给予体,通过改进的溶胶-凝胶法成功地制备了氮铈共掺杂介孔TiO2光催化剂.用X射线衍射(XRD)、透射电子显微镜(TEM)、傅里叶变换红外光谱(FT-IR)等分析手段对所得产物的结构和光学性能进行了表征.结果表明,所制备材料为锐钛矿晶型,具有7～10 nm的均一孔径,掺杂能够阻止TiO2的相转变,提高TiO2介孔结构的热稳定性.当共掺杂催化剂含氮2％、铈2％(物质的量分数)时对造纸废水的光催化降解效果最佳,色度和CODCr的去除率分别达到100％和72％.     

生理条件下PDF对Pb2+、Cu2+、Zn2+、Ca2+的吸附研究

在生理条件下(pH2和pH7，37℃)，用马铃薯膳食纤维(PDF)对金属离了Pb^2 、Cu^2 、Zn^2 、Ca^2 进行吸附试验。结果表明，两种酸度条件下PDF对Pb^2 的吸附较大，对Cu^2 、Zn^2 的吸附较小，对Ca^2 吸附很小；PDF用量增大(减小)，吸附量(qe)减小(增大)。PDF对重金属离了的吸附表明PDF具有较好的生理活性。用作膳食纤维时应根据需求，按照已研究的用量与吸附量关系配制。其吸附作用是化学吸附与物理吸附的综合结果。PDF的疏松结构和红外光谱中较多的醛羧基团证明了这一点。吸附数据线形拟合表明物理吸附符合Ligniur单分子层吸附机理。     

UV+H2O2和UV+H2O2+Fe2+化学氧化处理CEH漂白废水研究

采用UV+H2O2和UV+H2O2+Fe2+二种高级化学氧化工艺处理硫酸盐苇浆CEH漂白废水,研究了氧化剂用量、Fe2+浓度、初始pH值、处理时间等因素与处理效果(以COD和色度为指标)的关系.研究表明,添加Fe2+可大大加速体系对有机污染物氧化降解,H2O2用量对COD和色度的去除影响显著,硫酸盐苇浆CEH漂白混合废水pH值呈较强的酸性,适合于采用UV+H2O2+Fe2+工艺氧化处理.     

可见光检测-低压离子色谱法测定Fe3+、Cu2+、Zn2+、Fe2+

利用低压离子色谱柱，选用酒石酸一柠檬酸混合液作为洗脱体系，将Fe^3 、Cu^2 抖、Zn^2 、Fe^2 四种离子完全分离，柱后采用2-E(5-溴-2-吡啶)-偶氮]-5-二乙氨基苯酚(5-Br-PADAP)进行衍生反应，于波长560nm处进行检测。四种离子的检出限分别为0．14rng／L，0．006mg／L，0．003mg／L，0．05mg／L。方法用于实际样品分析，取得满意的结果。     

Effect of Ca2+ and Zn2+ on UO2 dissolution rates

The dissolution of UO(2) in a continuously stirred tank reactor (CSTR) in the presence of Ca(2+) and Zn(2+) was investigated under experimental conditions relevant to contaminated groundwater systems. Complementary experiments were performed to investigate the effect of adsorption and precipitation reactions on UO(2) dissolution. The experiments were performed under anoxic and oxic conditions. Zn(2+) had a much greater inhibitory effect on UO(2) dissolution than did Ca(2+). This inhibition was most substantial under oxic conditions, where the experimental rate of UO(2) dissolution was 7 times lower in the presence of Ca(2+) and 1450 times lower in the presence of Zn(2+) than in water free of divalent cations. EXAFS and solution chemistry analyses of UO(2) solids recovered from a Ca experiment suggest that a Ca-U(VI) phase precipitated. The Zn carbonate hydrozincite [Zn(5)(CO(3))(2)(OH)(6)] or a structurally similar phase precipitated on the UO(2) solids recovered from experiments performed in the presence of Zn. These precipitated Ca and Zn phases can coat the UO(2) surface, inhibiting the oxidative dissolution of UO(2). Interactions with divalent groundwater cations have implications for the longevity of UO(2) and the mobilization of U(VI) from these solids in remediated subsurface environments, waste disposal sites, and natural uranium ores.     

关于商高数(n+h)~2-n~2,2n(n+h),(n+h)~2+n~2

本文解决了一类商高数的Jes′manowicz猜测,即证明下列定理:设a=(n+h)~2-n~2、b=2n(n+h)、C=(n+h)+n~2,此处正整数n、h满足h~2=2n~2-1,则丢番图方程a+b~y=c~z仅有正整数解x=y=z=2。     

镁、锰离子对黄原胶生物合成的影响

通过添加不同浓度镁、锰的一系列摇瓶实验,研究野油菜黄单胞菌代谢过程中的关键酶：葡萄糖-6- 磷酸脱氢酶(G-6-PDH)和丙酮酸激酶(PYK)的活性变化,确定最佳单因素金属离子添加方案：Mg2+ 添加量0.4g/100ml、Mn2+ 添加量0.04g/100ml,随后进行罐发酵实验,从而对摇瓶实验结果进行验证并研究金属离子对黄原胶罐发酵生物合成的影响。实验结果表明：0.4g/100ml Mg2+ 可以较大程度提高G-6-PDH 的活性,与摇瓶实验结果基本一致;0.04g/100ml Mn2+ 大大提高了PYK 的活性,与摇瓶实验结果一致;5L 发酵罐中发酵液残糖总体呈下降趋势,在60h以后趋向平稳,Mg2+、Mn2+ 会一定程度上增加发酵液中残糖含量,从而降低碳源的利用率。     

改性壳聚糖水凝胶对废水中Cu2+、Cd2+和Pb2+的吸附

将改性壳聚糖与聚丙烯酸结合,制备N-羧甲基壳聚糖水凝胶(NCS-hydrogel)吸附剂,吸附废水中三种重金属元素.通过红外光谱仪、电镜扫描仪以及热重分析仪对NCS-hydrogel的形貌和结构进行了表征和分析.分别考察pH值、NCS-hydrogel使用量以及环境温度对所制备NCS-hydrogel吸附能力的影响.结...     

Effects of Ca2+ and Mg2+ on defluoridation in the electrocoagulation process

Because aqueous ions can influence the defluoridation of the electrocoagulation (EC) process, the effects of Ca(2+) and Mg(2+) were investigated. The behaviors and mechanisms of EC defluoridation in Ca(2+)-containing systems were different from those in Mg(2+)-containing systems. An increase in Ca(2+) concentration improved the defluoridation efficiency (ε(F)), but it could not change the optimal molar ratio of OH(-) and F(-) to Al(3+) (r(OH+F)). The highest ε(F) can usually be obtained at r(OH+F) = 3 for defluoridation. Only a small portion of Ca(2+) entered into the flocs, and Ca(2+) could not influence the mechanism of EC defluoridation. For the Mg(2+)-containing system, the optimal r(OH+F) increased with increasing Mg(2+) concentration. The optimal r(OH+F) was maintained at 3 after the Mg(2+) concentration was corrected using the obtained correction coefficient of 0.3435. About 50% to 70% of the total Mg(2+) entered into the flocs. From the XRD analysis, it was found that some Mg-Al-F layered double hydroxides (LDHs) were formed by Mg(2+), F(-), and Al(3+) during electrolysis. It is proposed for the first time that the formation of Mg-Al-F LDH is one of the mechanisms for EC defluoridation in systems containing both F(-) and Mg(2+).     

Sorption and desorption of Cd2+ and Zn2+ ions in apatite-aqueous systems

As a low-soluble phosphate mineral capable of binding various metal ions, apatite can be used to immobilize toxic metals in soils and waters. In the present research the factors affecting sorption and desorption of Cd2+ and Zn2+ ions on/from apatites are investigated. Batch experiments were carried out using synthetic hydroxy-, fluoride-, and carbonate-substituted apatites having various specific surface area (SSA). Apatite sorption capacity was found to depend mainly on its SSA, ranging from 16 to 78 and from 11 to 79 mmol per 100 g of apatite for Cd2+ and Zn2+, respectively. The solution composition (pH, and presence of Cl- and NO3- ions) had no essential impact on sorption. Desorption of bound cations depended both on the sorption level and solution composition. The amount of desorbed Cd2+ and Zn2+ increased proportionally to the amount of sorbed cations. However, apatites having higher sorption capacity release relatively less sorbed cations. Desorption increases with increasing Ca2+ concentration in the solution, reaching 8-20% of sorbed Cd2+ in 0.002 M, 10-35% in 0.01 M, and 33-45% in 0.05 M Ca(NO3)2 solution. Compared to nitrate solutions, the presence of Cl- ions in the solution promotes the release of bound cations. Desorption of Zn2+ is slightly higher than that of Cd2+. The desorption mechanism was assumed to include both ion-exchange and adsorption of Ca2+ ions on apatite surface.