天然沸石对甲基橙的吸附研究

用分光光度法研究了天然沸石对甲基橙的吸附行为.较低的pH、较高的温度有利于吸附,3h吸附基本达到平衡,增加溶液中NaCl、CaCl2的浓度降低沸石对甲基橙的吸附量.随着平衡浓度增加,吸附量增大,且吸附符合Langmuir等温吸附方程,30℃时最大吸附量为7.06mg.g-1.     

Effects of Complexes and pH Buffer Solution in Electrokinetic Oxidation Treatment on Sediments Chromium Removal

Three electrokinetic(EK) experiments were designed to study the remediation efficiency of Cr(Ⅲ) by EK-oxidation method and to investigate the influence of complexes and p H buffer solution in EK-oxidation process. Sediments Cr(Ⅲ) can be oxidized into Cr(Ⅵ) effectively by KMn O4, but the oxidation efficiency is not proportional to the dose of oxidant, and chemical oxidation process leads to a bit lower buffering capacity of the sediment. Compared with the simple EK remediation, the removal efficiency of total Cr in the sediments increased 32.6% by EK-oxidation method, and the concentrations of total chromium in the sediment showed increasing trend from the cathode to the anode after EK-oxidation treatment. The p H control and KMn O4 improved the removal of Cr(Ⅵ) and total Cr from the sediments. Due to stronger complexation action of citric acid with Cr(Ⅲ) in sediments, citric acid in the catholyte obviously increased the removal rate of total Cr in sediments. Finally, the removal rate of total Cr from sediments reached 60.9% by adding complex and controlling the p H of cathode and anode pond solution on EK-oxidation processes.     

不同化学方法对印染、造纸废水的深度处理研究

采用Fenton试剂氧化法、NaClO氧化法、KAl(SO4)2混凝沉淀法分别对新乡市某印染厂和某造纸厂的二级生化出水进行深度处理.考察了废水初始pH,3种试剂投加量对废水COD和色度的影响.研究结果表明:室温下,反应时间30min,3种方法对印染废水、造纸废水的深度处理均具有明显效果.Fenton试剂氧化法对两种废水的处理效果明显优于另外两种方法,其对印染废水深度处理的最适条件为:pH 4,H2O20.8mg·L-1、FeSO4150mg·L-1,COD、色度去除率分别达到81.5%、75.0%,COD和色度分别从243mg·L-1、128降至45mg·L-1、32;其对造纸废水深度处理的最适条件为pH 4,H2O20.6mL·L-1、FeSO4200mg·L-1,COD、色度去除率分别达到73.8%、75.0%,COD和色度分别从351mg·L-1、128降至92mg·L-1、32.两种废水经过Fenton试剂氧化法处理后完全可以达到地方工业行业废水排放标准.     

Reductive recovery of manganese from low-grade manganese dioxide ore using toxic nitrocellulose acid wastewater as reductant

The hydrometallurgical strategy of extracting Mn from low-grade Mn ores has attracted attention for the production of electrolytic manganese metal (EMM). In this work, the reductive dissolution of low-grade MnO₂ ores using toxic nitrocellulose acidic wastewater (NAW) as a reductant was investigated for the first time. Under the optimized conditions of an MnO₂ ore dosage of 100 g·L-1, an ore particle size of -200 mesh, concentrated H₂SO₄-to-NAW volume ratio of 0.12, reaction temperature of 90℃, stirring speed at 160 r·min-1, and a contact time of 120 min, the reductive leaching efficiency of Mn and the total organic carbon (TOC) removal efficiency of NAW reached 97.4% and 98.5%, respectively. The residual TOC of 31.6 mg·L-1 did not adversely affect the preparation of EMM. The current process offers a feasible route for the concurrent realization of the reductive leaching of Mn and the treatment of toxic wastewater via a simple one-step process.     

化学沉淀法去除木薯制备酒精废水中氨氮的试验研究

针对NH_3-N质量浓度为500~900mg/L木薯制备酒精的废水,采用正交试验及单因素试验研究了用化学沉淀法去除废水中氨氮的工艺条件,结果表明:以MgCl_2·6H_2O和Na2HPO4·12H_2O为沉淀剂,在pH=9.0时废水溶液中PO_4~(3-)与Mg~(2+)和NH_4~+一起发生沉淀反应生成MgNH4PO4·6H_2O,从而达到去除废水中的氨氮的目的;影响废水中的氨氮去除率的因素依次为n(Mg~(2+):NH_4~+),反应时间,n(PO_4~(3-)∶NH_4~+)和pH值。最佳反应条件是当pH=9.0,n(Mg~(2+))∶n(NH_4~+)∶n(PO_4~(3-))=1.4∶1.0∶1.2,常温下反应30min,静置30min,该工艺条件下,对初始氨氮为644.5mg/L的木薯制备酒精的废水进行处理,其氨氮的去除率90%。     

膨胀蛭石吸附氨氮的研究

研究了膨胀蛭石对氨氮的吸附容量及pH、温度、进水氨氮浓度和膨胀蛭石用量对氨氮去除率的影响.结果表明,膨胀蛭石对氨氮的饱和吸附量为17.32 mg.g-1;氨氮去除率在pH 4.0~7.0范围内大于65%;在进水氨氮浓度低于200 mg.L-1时,氨氮去除率随着进水氨氮浓度增加而增大,为膨胀蛭石作为一种新型填料提供了基础数据和理论依据.     

表面改性活性炭的制备及其去除污水中Cd~(2+)的试验研究

以花生壳生物质炭(PSB)为原料,采用KOH活化法制备了比表面积为461 m2·g-1的花生壳活性炭(K-PSB),利用氮气吸附脱附等温线、SEM等对样品进行了表征,并将孔隙结构发达的花生壳活性炭用于重金属Cd2+的吸附,考察反应时间、溶液p H值、花生壳活性炭的投加量等对Cd2+吸附的影响。结果表明:随着吸附时间的推移,Cd2+的吸附量逐渐增加直至达到平衡,当Cd2+浓度为50 mg·L-1,PH值等于6,投加量为1 g·L-1时,花生壳活性炭对Cd2+的吸附效果最佳;该吸附是一个吸热反应,随着温度的增加,吸附量逐渐增大。     

Photodegradation of bisphenol a induced by metal ions in aqueous solution in the presence of ascorbic acid

The photodegradation of bisphenol A (BPA) in aqueous solution containing metal ions and ascorbic acid (AsA) was investigated. After strong irradiation, the aqueous solution containing AsA and Cu²⁺ could produce hydroxyl radicals that induced the photodegradation of BPA. The photodegradation efficiency of BPA in the solution containing 70 μmol·L⁻¹ Cu²⁺ and 15 mg·L⁻¹ AsA reached 59% at pH 6.0 after 4 hours irradiation with high pressure mercury lamp. The photodegradation efficiency of BPA reached 10% after 4 hours irradiation with daylight lamp in the presence of 70 μmol·L⁻¹ Cu²⁺ and 15 mg·L⁻¹ ascorbic acid. BPA was not degraded in the aqueous solution only containing AsA or Cu²⁺. The BPA photodegradation in aqueous solution containing AsA and Fe³⁺ was weaker than in aqueous solution that containing AsA and Cu²⁺ at the same concentration. This work showed a new route of the BPA photodegradation in aqueous environment. Biography: PENG Zhang’e (1970–), female, Ph. D. candidate, research direction: aquatic environmental chemistry.     

Preparation and electrochemical properties of carbon-coated LiFePO4 hollow nanofibers

Carbon-coated LiFePO₄ hollow nanofibers as cathode materials for Li-ion batteries were obtained by coaxial electrospinning. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller specific surface area analysis, galvanostatic charge–discharge, and electrochemical impedance spectroscopy (EIS) were employed to investigate the crystalline structure, morphology, and electrochemical performance of the as-prepared hollow nanofibers. The results indicate that the carbon-coated LiFePO₄ hollow nanofibers have good long-term cycling performance and good rate capability: at a current density of 0.2C (1.0C = 170 mA·g-1) in the voltage range of 2.5–4.2 V, the cathode materials achieve an initial discharge specific capacity of 153.16 mAh·g-1 with a first charge–discharge coulombic efficiency of more than 97%, as well as a high capacity retention of 99% after 10 cycles; moreover, the materials can retain a specific capacity of 135.68 mAh·g-1, even at 2C.     

碱熔融法合成NaA和NaX型粉煤灰沸石对亚甲蓝的吸附动力学研究

以粉煤灰为原料采用碱熔融法合成了两种单一沸石矿物种的NaA和NaX型沸石,通过静态吸附实验,研究了这两种沸石对水溶液中亚甲蓝(MB)的吸附特性,从动力学角度探讨了吸附机理.结果表明:在所研究的浓度和pH值条件下,合成NaA和NaX型沸石对亚甲蓝的吸附平衡数据符合Langmuir等温吸附方程,静态饱和吸附量(Qm)分别为37.81和43.02 mg.g-1;氢键作用是影响亚甲蓝吸附行为的主要因素;通过动边界模型研究表明,两种沸石对亚甲蓝吸附过程的速度控制步骤为液膜扩散,且亚甲蓝的吸附过程符合伪二级方程.     

天然沸石的改性及其吸附Pb~(2+);Cu~(2+)的研究

以天然沸石为原料,结合废水处理应用中对吸附材料的要求,采用酸、碱、盐对沸石进行了改性;并利用改性沸石进行了去除溶液中Pb2+,Cu2+的方法、效果、影响因素和吸附机理的研究.结果表明,NaOH改性的沸石对Pb2+,Cu2+的吸附能力大幅度提高;随着初始浓度的增加,沸石的吸附容量也增加;改性沸石对Pb2+,Cu2+的吸附很快,在较短的时间内即可达到平衡;溶液的pH值越高越有利于沸石吸附Pb2+,Cu2+.     

Modulation of active Cr(III) complexes by bath preparation to adjust Cr(III) electrodeposition

The preparation process of the Cr(III) bath was studied based on a perspective of accelerating the formation of active Cr(III) complexes. The results of ultraviolet-visible absorption spectroscopy (UV-Vis) and electrodeposition showed that active Cr(III) complexes in the bath prepared at room temperature in several days were rare for depositing chromium. The increase of heating temperature, time, and pH value during the bath preparation promoted the formation of active Cr(III) complexes. The chromium deposition rate increased with the concentration of active Cr(III) complexes increasing. Increasing the heating temperature from 60 to 96℃, the chromium deposition rate increased from 0.40 to 0.71 μm/min. When the concentration of active Cr(III) complexes increased, the grain size of Cr coatings increased, and the carbon content of the coating decreased. It is deduced that Cr(H₂O)₄(OH)L2+ (L is an organic ligand, and its valence is omitted) is a primary active Cr(III) complex.     

Cu-Mn/Fe3O4@SiO2@KCC纳米催化剂制备及其 催化臭氧化降解对苯二甲酸性能

采用微乳法及浸渍法合成负载型铜锰单分散核壳磁性纤维状纳米催化剂(Cu-Mn/Fe_3O_4@SiO_2@KCC),利用XRD、TEM、BET、VSM等手段对其表征;并通过构建类均相催化臭氧化降解对苯二甲酸(100 mg·L~(-1))的研究,考察其催化性能。结果表明:臭氧通入量13.92 mg·min~(-1)、催化剂投加量40 mg·L~(-1)和pH=9时,对苯二甲酸去除率高达90.97%,TOC去除率可达30%。五次循环试验后对苯二甲酸降解率仍稳定在88.23%。     

盐酸环丙沙星在不同模拟水体中的降解与残留

 通过反相高效液相色谱法研究在不同模拟水体中,溶液质量浓度、pH对盐酸环丙沙星（CPFX）在水和底泥中含量变化的影响,分析其在模拟水体中降解和残留规律。研究结果表明：在1、5、10 mg·L^-1三个CPFX溶液质量浓度中,光降解度最高的溶液质量浓度为1 mg·L^-1,自然光照下,72 h后盐酸环丙沙星在有底泥和无底泥的水体中残留率分别为19 %和20 %,光降解率与初始质量浓度成反比。在pH分别为3、5、9、11条件下,pH=9的微碱性环境下最易光降解,而当pH=3时其光稳定性最佳,48 h后水体残留率分别为22.6 %和95.7 %。盐酸环丙沙星进入模拟水生态系统后,水体中CPFX质量浓度迅速下降,45 d后检测不到它的存在;底泥中CPFX质量分数迅速上升,之后缓慢下降,45 d后底泥中仍有一定残留量,达到93.86 μg·kg^-1。     

药物中半胱氨酸的流动注射荧光测定方法研究

 在近中性介质及聚乙烯醇(PVA)存在下,半胱氨酸能熄灭一个新的荧光试剂5-(4-氯苯基)-8-苯磺酰氨基喹啉(CPBSQ)与Cu(Ⅱ)络合体系的荧光的反应.基于此现象,本文建立了一个测定半胱氨酸的流动注射荧光熄灭方法.结果表明,在λ_ex/λ_em=327/368nm处测定,方法的进样频率为64h-1,检测范围为0.05～5.5μg·mL^-1,检出下限为0.01μg·mL^-1,对4.0μg·mL^-1半胱氨酸平行测定11次的相对标准偏差为1.52%.大量存在的常见金属离子、蛋白质及很多不带巯基的氨基酸不干扰测定.应用此方法测定了某些注射液针剂中半胱氨酸的含量,结果满意.     

零价纳米铁对水中Cr(VI)的吸附动力学研究

 为开发新型环境材料,改进治理技术以控制或修复污染水体中Cr(Ⅵ),采用NaBH₄还原Fe³⁺制备纳米级零价铁(NZVI).X射线衍射(XRD)及扫描电镜(SEM)测试表明,制备的纳米铁颗粒纯度高、粒径小、粒度均匀.以Cr(VI)为研究对象,批试验考查了溶液初始浓度、NZVI投加量、温度等条件对去除效果的影响,研究了NZVI对Cr(VI)的吸附动力学.结果表明,室温、pH值为6-7时,NZVI加入量为0.15g/L,水体中Cr(VI)浓度为30.0mg/L时,Cr(VI)最大吸附量为198.02mg/g,Cr(VI)在NZVI上的吸附符合准二级动力学方程.实验结果显示,纳米零价铁能快速去除水体中Cr(VI);溶液初始浓度、NZVI投加量等是影响Cr(VI)脱除的主要因素,Cr(VI)去除率随反应温度和NZVI投加量升高而升高,随初始浓度升高而降低.实验表明,该纳米铁在废水除铬领域具有较好的应用前景.     

Flow-injection microcolumn on-line preconcentration for the determination of chromium (VI)

A rapid and sensitive on-line preconcentration method for spectrophotometric determination of chromium (VI) in nature water is described. Preconcentration and determination are based on (i) the quantitative and fast adsorption of chromium (VI) on the high surface area nanometer-size TiO₂ (anatase) powders, which prepared by a sol-gel method from hydrolysis of TiCl₄ and (ii) the quantitative and reproducible elution of Cr (VI) by 2.0 mol·L⁻¹ HCl. A mini-column system for preconcentration is developed, Cr(VI) on the mini-column is eluted and merged with a stream water and DPCB (1,5-diphenylcarbazide) as the chromogenic reagent. The proposed system permits throughputs of 6 sample h⁻¹ (0.001 μg·mL⁻¹ Cr(VI)) or 20 sample h⁻¹ (0.1 μg·mL⁻¹ Cr(VI)). The preconcentration factor is 55. The detection limit is 0.8 ng · mL⁻¹ Cr(VI). The reproducibility is satisfactory with a relative standard deviation of less than 3.35% (0.01 μg·mL⁻¹ Cr(VI),n=5). Supported by the National Natural Science Foundation of China Ma Wanhong: born in 1961, Ph. D. Graduate student, Associate professor     

天然沸石对含镍废水的吸附研究

采用天然沸石对含镍废水进行吸附特性研究。考察了沸石粒径、接触时间、镍的初始浓度及溶液pH值等因素对沸石吸附镍的影响。结果表明,吸附25min后吸附接近平衡,溶液pH在4～6范围内,沸石对Ni2+去除效果较好,沸石粒径减小,Ni2+初始浓度提高,镍的吸附量增大。沸石对Ni2+的吸附动力学及热力学研究表明,在一定的实验条件下,Ni2+在沸石表面主要以单分子层吸附为主,符合Langmuir吸附等温式且吸附过程遵循准二阶动力学吸附模型(相关系数R>0.999)。     

Application of Nanometer-Size Titanium Dioxide in Extreme-Trace V（Ⅴ） Analysis

0Introduction Vanadiumplaysanimportantroleinmodernindustry,es peciallyinsteelandchemicalindustry.Forinstance,itscompoundsarewidelyappliedintheproceduresofvitrioland petroleumchemicalmanufactureascatalyzers[14].Vanadium hasseveralvalences,butgenerallyitslowvalencesturnintohighoneseasilyinenvironment[5].BecauseV(Ⅴ)isthemost stableandpoisonousone,weoftenlayemphasisonitinenvi ronmentalpollutioncontrol.Vanadiumexistsinenvironmentalwaterwithextremelylowconcentration.Inseawateritscontentislessthan…     

纳米零价铁富集水体中的铀

应用纳米零价铁(nZVI)富集水体中的铀不但能够回收珍贵的铀资源,同时还可以避免放射性物质对环境的污染.研究结果表明纳米零价铁可快速高效地分离水体中的铀.nZVI对铀的最大富集负荷达到920.16 mg/g,溶液中铀离子的质量浓度可降低至0.03 mg/L以下.弱酸性的水质条件促进nZVI对铀的分离,且分离和还原效率随着nZVI投加量的增加、HCO-₃浓度的降低而升高.高浓度的铀离子可水解形成UO₃·2H₂O沉淀,但Fe⁰和Fe²⁺的还原作用是nZVI分离铀离子的主要反应机理.nZVI富集尾矿水中铀资源的过程中可同步去除多种共存重金属污染物.