土酸溶液中溴化十六烷基吡啶对锌的缓蚀作用及吸附热力学研究

用失重法研究了土酸溶液中溴化十六烷基吡啶对锌的缓蚀作用，发现溴化十六烷基吡啶在锌表面上的吸附是产生缓蚀作用的重要原因，且吸附规律服从Langmuir吸附等温式。用Sekine方法处理实验数据，从而获得了吸附过程△H^0、△S^0和△G^0等一系列重要热力学参数。     

氨基磺酸溶液中溴化十六烷基吡啶对碳钢的缓蚀作用和吸附热力学研究

采用失重法考察了不同温度下5％氨基磺酸中,不同浓度的溴化十六烷基吡啶对碳钢的缓蚀作用;并对氨基磺酸介质中溴化十六烷基吡啶在碳钢表面吸附热力学进行了研究。溴化十六烷基吡啶低浓度时,随浓度增大,缓蚀作用增强;当其浓度达到一定值后,缓蚀作用基本保持不变。实验结果表明,溴化十六烷基吡啶在碳钢表面产生单分子层吸附,并且满足Langmuir吸附规律。△G^0〈0,吸附过程可以自发进行,并且随着温度升高△G^0增大,吸附作用降低。△H^0〈0,表明反应是放热过程。△S^0〈0表示随着缓蚀过程的进行,体系进入更为有序状态。     

盐酸溶液中异喹啉在锌表面的吸附及其缓蚀作用

锌换热设备表面积垢常用盐酸进行清洗,因此研究盐酸介质中锌缓蚀剂有重要意义.采用失重法和电化学方法研究了异喹啉在0.8 mol/L盐酸中对锌的吸附及缓蚀作用、吸附热力学和吸附动力学.结果表明,随异喹啉浓度增大,缓蚀率增大,当浓度增大到1g/L后,缓蚀率达到最大值.随温度升高,吸附系数减小,缓蚀率降低.吸附过程是放热过程,△H0=-30.27 kJ/mol.吸附过程熵值减小,且随温度升高,熵变下降.加入异喹啉后腐蚀电流明显减小,过程活化能由3.29 kJ/mol升高至25.56 kJ/mol.异喹啉明显抑制阴极过程,是一种阴极型缓蚀剂.     

盐酸介质中锌缓蚀剂的电化学研究

采用电化学极化曲线法研究了在盐酸介质中盐酸吖啶、苯扎溴铵、溴代十六烷基吡啶、丙炔醇等对锌的缓蚀作用。结果表明，它们的加入提高了腐蚀反应的活化能，均为阴极型缓蚀剂，缓蚀率排序为盐酸吖啶〉苯扎溴铵〉溴代十六烷基吡啶〉丙炔醇。     

硫脲和溴代十六烷基吡啶对X70钢在30%乳酸溶液中的协同缓蚀

目前,对X70钢在乳酸溶液中的缓蚀行为少有报道.采用交流阻抗法和极化曲线法研究硫脲(TU)和溴代十六烷基吡啶(CPB)复配前后对X70钢在30%乳酸溶液中的缓蚀作用.研究发现:在30%乳酸体系中,TU和CPB对X70钢均有缓蚀作用;硫脲和溴代十六烷基吡啶复配后,缓蚀性能增强.当缓蚀剂的总浓度为20 mg/L,TU和CPB质量浓度比为1:1时缓蚀效果最佳.     

溴化十六烷基三甲基铵在麦壳上的吸附研究

以麦壳为吸附剂,研究其对污水中阳离子表面活性剂溴化十六烷基三甲基铵(CTMAB)的吸附特性。考察了吸附剂用量、吸附时间、CTMAB初始浓度、溶液pH、吸附液盐度、温度等条件对吸附的影响。结果表明:随着麦壳用量的增加,吸附量逐渐减小;麦壳对CTMAB的吸附反应速率很快,40min即可达到吸附平衡;随着CTMAB初始浓度以及pH值的增加,吸附量均逐渐增大;随着Ca2+浓度的增大,吸附量逐渐减小;随着反应温度的升高,吸附量缓慢增大。麦壳对CTMAB的吸附符合Langmuir和Freundlich模型。     

烷基吡啶盐对铝的缓蚀作用

通过阳离子表面活性剂烷基吡啶盐在铝表面上的吸附，研究了不同温度下的酸碱介质中烷基吡啶盐对金属铝的缓蚀作用。     

烷基三唑类缓蚀剂的合成及对N80碳钢的缓蚀性能

目前,对引入长链烷基的三唑类缓蚀剂在盐酸中对金属缓蚀性能的研究尚存在着较大的空白。合成并探讨了烷基三唑类缓蚀剂对碳钢的缓蚀作用机理,采用失重法和电化学法测试评价了3种不同碳链长度的三唑类缓蚀剂对N80碳钢在盐酸中的缓蚀性能,采用扫描电镜(SEM)观察了其缓蚀前后的表面形貌。结果表明:3种缓蚀剂均能有效抑制盐酸对N80碳钢的腐蚀,为阴极抑制型缓蚀剂,在N80碳钢表面的吸附服从Langmuir等温吸附模型;在较低温度下,缓蚀剂碳链越长,缓蚀性能越好;缓蚀剂分子中吸附基团的比例随着碳链的增长而降低,随着温度的增加,缓蚀剂分子热运动加剧,吸附能力降低,碳链较短的缓蚀剂高温条件下能达到更高的缓蚀率。     

吐温-60对钢在H2SO4中的缓蚀性能

用失重法研究了非离子表面活性剂吐温-60对冷轧钢在0.5-7.0 mol/L H2SO4溶液中的缓蚀作用。结果表明：吐温-60对冷轧钢在1.0 mol/L H2SO4溶液中具有良好的缓蚀作用,且在钢表面的吸附符合校正的Langmuir吸附模型。缓蚀率随缓蚀剂浓度的增加而增大,但随温度和硫酸浓度的增加而减小。求出了相应的吸附热力学（吸附自由能ΔG^0, 吸附焓ΔH^0, 吸附熵ΔS^0）和动力学参数（腐蚀速率常数k, 腐蚀动力学常数B）,并根据这些参数讨论了缓蚀作用机理。     

溴化十六烷基吡啶改善二甲酚橙指示剂性能的研究

本文研究了溴化十六烷基吡啶(CPB)的存在使二甲酚橙(XO)作配位滴定指示剂的性能得到改善的情况。发现CPB的加入可以使XO的最大吸收波长入_(max)兰移约5nm,使Pb~(2)—XO和Zn~(2+)—XO配合物的最大吸收波长入_(max)红移约4nm,增大了滴定终点变色的对比度(使△入增大约9nm),终点锐度增大滴定误差减少。同时还发现,CPB的存在可以使XO的应用pH范围从pH≤6扩大到pH≤9.8。因而确认CPB-XO是优于XO的配位滴定指示剂。试验表明加入CPB的适宜浓度为0.007～0.008%,即每100mL溶液中,加0.1％CPB7～8mL.     

Removal of nitrate from aqueous solution using cetylpyridinium bromide (CPB) modified zeolite as adsorbent

Surfactant modified zeolites (SMZ) with different coverage types were prepared by loading the cetylpyridinium bromide (CPB) onto the surface of the natural zeolites. The adsorption behavior of nitrate on SMZ was investigated. Natural zeolite and SMZ with monolayer CPB coverage were inefficient for the removal of nitrate from aqueous solution. However, SMZ with patchy bilayer or bilayer CPB coverage was efficient in nitrate removal, and the nitrate adsorption capacity of SMZ increased with its CPB loading. For typical SMZ with bilayer CPB coverage, the nitrate adsorption process was well described by the pseudo-second-order kinetic model, and the experimental isotherm data fitted well with the Langmuir, Freundlich and Dubinin-Redushkevich isotherm models. Thermodynamic parameters such as Gibbs free energy change, enthalpy change and entropy change were calculated and the results showed that the adsorption of nitrate on SMZ was spontaneous and exothermic in nature. The presence of competing anions such as chloride, sulfate and bicarbonate ions slightly reduced the nitrate adsorption efficiency. Anionic exchange and electrostatic interaction were proven to be the main mechanisms that govern the adsorption of nitrate on SMZ.     

Preparation of porous nano-calcium titanate microspheres and its adsorption behavior for heavy metal ion in water

Using D311 resin as a template, porous nano-calcium titanate microspheres (PCTOM) were prepared by a citric acid complex sol-gel method and characterized by X-ray diffraction (XRD), SEM and FTIR. The method's adsorption capabilities for heavy metal ions such as lead, cadmium and zinc were studied and adsorption and elution conditions were investigated. Moreover, taking the cadmium ion as an example, the thermodynamics and kinetics of the adsorption were studied. The results show that the microspheres were porous and were made of perovskite nano-calcium titanate. The lead, cadmium and zinc ions studied could be quantitatively retained at a pH value range of 5-8. The adsorption capacities of PCTOM for lead, cadmium and zinc were found to be 141.8 mg g(-1), 18.0 mg g(-1) and 24.4 mg g(-1) respectively. The adsorption behavior followed a Langmuir adsorption isotherm and a pseudo-second-order kinetic model, where adsorption was an endothermic and spontaneous physical process. The adsorbed metal ions could be completely eluted using 2 mol L(-1) HNO(3) with preconcentration factors over 100 for all studied heavy metal ions. The method has also been applied to the preconcentration and FAAS determination of trace lead, cadmium and zinc ion in water samples with satisfactory results.     

Preconcentration and separation of copper, nickel and zinc in aqueous samples by flame atomic absorption spectrometry after column solid-phase extraction onto MWCNTs impregnated with D2EHPA-TOPO mixture

A solid phase extraction method has been developed for the determination of copper, nickel and zinc ions in natural water samples. This method is based on the adsorption of copper, nickel and zinc on multiwalled carbon nanotubes (MWCNTs) impregnated with di-(2-ethyl hexyl phosphoric acid) (D2EHPA) and tri-n-octyl phosphine oxide (TOPO). The influence of parameters such as pH of the aqueous solution, amount of adsorbent, flow rates of the sample and eluent, matrix effects and D2EHPA-TOPO concentration have been investigated. Desorption studies have been carried out with 2 mol L(-1) HNO(3). The copper, nickel and zinc concentrations were determined by flame atomic absorption spectrometry. The results indicated that the maximum adsorption of copper, nickel and zinc is at pH 5.0 with 500 mg of MWCNTs. The detection limits by three sigma were 50 μg L(-1) for copper, 40 μg L(-1) for nickel and 60 μg L(-1) zinc. The highest enrichment factors were found to be 25. The adsorption capacity of MWCNTs-D2EHPA-TOPO was found to be 4.90 mg g(-1) for copper, 4.78 mg g(-1) for nickel and 4.82 mg g(-1) for zinc. The developed method was applied for the determination of copper, nickel and zinc in electroplating wastewater and real water sample with satisfactory results (R.S.D.'s <10%).     

硝酸溶液中十二烷基磺酸钠对锌的缓蚀作用及吸附热力学研究

在不同的温度和浓度下,在3％硝酸溶液中,利用失重法试验,得到十二烷基磺酸钠在金属锌表面的吸附热力学数据以及其对金属锌的缓蚀作用。结果表明,十二烷基磺酸钠在锌表面进行单分子层吸附,抑制锌腐蚀。温度升高,吸附能力减弱,缓蚀效率下降。对实验数据进行分析,得到相应的焓变、熵变等一系列热力学数值。     

席夫碱基聚乙二醇(400)月桂酸酯表面活性剂在碱性锌电池中的缓蚀性能

为了研发一种能应用于碱性锌电池的代汞缓蚀添加剂,以解决锌电极易变形、长枝晶等问题,合成了3种席夫碱基聚乙二醇(400)月桂酸酯表面活性剂(M1、M2、M3),通过失重法、电化学技术、表面分析等方法研究了其在6 mol/L KOH电解液(饱和Zn O)中对锌电极的缓蚀效果。结果表明:缓蚀率随席夫碱基表面活性剂浓度升高而增加,室温下3种席夫碱基表面活性剂中M3缓蚀能力最强,缓蚀率最高达92.14%,缓蚀能力大小为M3M2M1,属于抑制阴极型缓蚀剂;表面分析揭示3种席夫碱基表面活性剂在锌电极表面上形成吸附层,其吸附符合Langmuir等温吸附模型,吸附平衡常数较大,M1、M2、M3的Kads分别为5 875.441,18 750.012,187 500.117 L/mol,适合作为碱性锌电池的缓蚀添加剂。     

Taguchi optimization approach for Pb(II) and Hg(II) removal from aqueous solutions using modified mesoporous carbon

Using the Taguchi method, this study presents a systematic optimization approach for removal of lead (Pb) and mercury (Hg) by a nanostructure, zinc oxide-modified mesoporous carbon CMK-3 denoted as Zn-OCMK-3. CMK-3 was synthesized by using SBA-15 and then oxidized by nitric acid. The zinc oxide was loaded to the modified CMK-3 by the equilibrium adsorption of Zn(II) ions from aqueous solution followed by calcination to convert zinc nitrate to zinc oxide. The CMK-3 had porous structure and high specific surface area which can accommodate zinc oxide in a spreading manner, the zinc oxide connects to the carbon surface via oxygen atoms. The controllable factors such as agitation time, initial concentration, temperature, dose and pH of solution have been optimized. Under optimum conditions, the pollutant removal efficiency (PRE) was 97.25% for Pb(II) and 99% for Hg(II). The percentage contribution of each controllable factor was also determined. The initial concentration of pollutant is the most influential factor, and its value of percentage contribution is up to 31% and 43% for Pb and Hg, respectively. Our results show that the Zn-OCMK-3 is an effective nanoadsorbent for lead and mercury pollution remediation. Langmuir and Freundlich adsorption isotherms were used to model the equilibrium adsorption data for Pb(II) and Hg(II).     

Comparison for adsorption modelling of copper and zinc from aqueous solution by Ulva fasciata sp

The removal of copper and zinc from aqueous solution by adsorption on Ulva fasciata sp. was studied, as a function of contact time and pH of the solution. Adsorption of copper and zinc on U. fasciata sp. was compared. It was shown that U. fasciata sp. has high metal removal efficiency. The maximum adsorption capacity of U. fasciata sp. for copper and zinc was 26.88 and 13.5mg/g, respectively. The adsorption of copper and zinc on U. fasciata sp. was increased with increase in pH from 2 to 5 and decreased with increase in pH from 5 to 10. The Freundlich and Langmuir model can describe the adsorption equilibrium of copper and zinc on U. fasciata sp. The Freundlich and Langmuir constants for adsorption of copper and zinc on U. fasciata sp. were determined.     

负载纳米氧化锌多孔碳吸附剂的制备及其结构研究

半导体纳米粒子光催化降解VOC是一种有效、经济的有机废气处理方法,本论文研究了纳米氧化锌改性的多孔碳材料的制备、结构及其对挥发性有机物的光催化分解性能.结果表明,可利用微乳液法合成并经高温煅烧得到负载于多孔碳材料上的纳米氧化锌.制备条件如反应物浓度、配比、沉淀剂种类等条件对产品的形貌、氧化锌纳米颗粒大小和负载量有明显的影响.负载纳米氧化锌微粒多孔炭吸附剂既保持了多孔炭材料的多孔性,又具有一定催化分解低浓度挥发性有机污染物的能力.     

微波加热烟杆制备微孔活性炭的研究

研究了微波加热烟杆氯化锌活化法制备微孔活性炭的新工艺.采用正交试验研究了氯化锌浓度、浸渍时间、微波功率和活化时间对活性炭得率和吸附性能的影响.最佳工艺条件为ZnCl2浓度25%,浸渍时间36h,微波功率为700W,加热时间为16 min时,所制备的活性炭的碘吸附值为1059.32 mg/g,亚甲基蓝吸附值为21 mL/0.1g,得率为32.90 %.该工艺将常规加热方法的预热、干燥、炭化和活化简化为一个过程,所需要加热时间仅为传统方法的1/13,产品活性炭的亚甲基蓝吸附值为国家一级品标准的2.33倍.同时测定了该活性炭的氮吸附等温线,通过BET法计算了活性炭的比表面积,并通过H-K方程、D-A方程和密度函数理论(DFT)表征了活性炭的孔结构.结果表明:该活性炭为微孔型,BET比表面积为1214m2/g,总孔容为0.7387 mL/g,微孔占总孔容74.03%,中孔占24.54%,大孔占1.43%.     

Adsorption of zinc on bed sediment of River Hindon: adsorption models and kinetics

The paper presents a study of zinc adsorption using the experimental data on bed sediments of River Hindon in western Uttar Pradesh (India). The effect of various operating variables, viz., initial concentration, solution pH, sediment dose, contact time, and particle size, have been studied. The optimum contact time needed to reach equilibrium was of the order of 60 min and was independent of initial concentration of zinc ions. The extent of adsorption increased with an increase of pH. Furthermore the adsorption of zinc increases with increasing adsorbent doses and decreases with the adsorbent particle size. The content of iron, manganese and organic matter in various fraction of sediment decreases with increasing particle size indicating the possibility of the two geochemical phases to act as the active support material for the adsorption of zinc ions. The adsorption data follows both Langmuir and Freundlich adsorption models. Isotherms were used to determine thermodynamic parameters, viz., free energy change, enthalpy change and entropy change. The negative values of free energy change indicate spontaneous nature of the adsorption while positive values of enthalpy change suggest the endothermic nature of the adsorption of zinc on bed sediment of the River Hindon. The positive values of entropy change indicate randomness at the solid/solution interface.