酸改性高岭土对含Cd~(2+)和Pb~(2+)废水的吸附研究

采用酸改性高岭土进行SEM和FTIR表征,考察其对含Cd~(2+)、Pb~(2+)废水的吸附特性及机理。结果表明:与原矿高岭土对比发现,酸改性高岭土片层状结构变薄变小,表面基团组成发生明显的变化;对于20 m L初始浓度为40 mg·L~(-1)的Cd~(2+)、Pb~(2+)溶液,当p H为5.8,酸改性高岭土投加量50 g·L~(-1)时,吸附效果最好;利用Freundlich和Langmuir方程对吸附等温线进行拟合,Langmuir方程拟合效果更优,表明其吸附过程为单分子层吸附;吸附机理服从准二级动力学方程,其计算吸附量与实验测量值仅偏差2.87%。     

黄原酸化交联壳聚糖树脂对Ag(Ⅰ)的吸附

采用微波辐射下制备的黄原酸化交联壳聚糖树脂(XCCTS)来吸附水溶液中的Ag(Ⅰ),研究了pH值和温度对XCCTS吸附性能的影响,并用FT-IR和XRD对XCCTS吸附Ag(Ⅰ)前后的结构进行了表征.结果表明,XCCTS可有效吸附水中的银离子,pH值和温度对XCCTS吸附Ag(Ⅰ)有显著影响,在pH=4.0和50℃时XCCTS可获得最大吸附量.采用Lagergren一级和拟二级动力学模型对XCCTS吸附Ag(Ⅰ)的动力学数据进行了分析.吸附过程更符合拟二级动力学模型.分别用Langmuir和Freundlich等温线模型对吸附平衡数据进行了处理,并计算了Ag(Ⅰ)吸附过程的热力学参数.实验数据既符合Langmuir等温方程又符合Freundlich等温方程,但用Langmuir方程拟合的相关系数相对更大.吸附过程是自发的吸热过程.     

一种新生物质吸附去除水体中直接大红

法国梧桐球果制备生物吸附剂,研究了其对水体中直接大红的吸附作用,研究结果表明法国梧桐球果能有效的吸附水体中的直接大红.通过不同影响因素下(pH、吸附剂量和温度)的吸附试验,确定了试验的最佳条件,并且得出了吸附平衡和动力学参数.25℃时吸附经7 h接近平衡,并且随着温度升高吸附接近平衡的时间明显缩短,35℃和45℃时分别为3 h和2 h.试验结果显示吸附过程符合一级和二级动力学吸附模型,二级吸附方程的数据拟合优于一级吸附方程,由动力学常数可求得吸附过程的表观活化能Ea=536.7 kJ/mol.吸附等温线的研究表明直接大红吸附符合Langmuir和Freundlich吸附等温方程,由Langmuir吸附等温方程可求得直接大红的最大吸附量为66.23 mg/g.     

HPD-100大孔树脂吸附葛根异黄酮的热力学和动力学

通过298、308 K和318 K温度下的平衡吸附实验和298 K下的动力学实验,考察了HPD-100大孔吸附树脂吸附水溶液中葛根异黄酮的热力学和动力学过程.分别用Langmuir和Freundlich等温方程对热力学数据进行拟合并计算得到各热力学参数,结果表明,HPD-100树脂对水溶液中葛根异黄酮的吸附可用Freundlich吸附模型描述(相关系数大于0.992),吸附为不均匀表面的多分子层吸附.负的热力学焓变和吉布斯自由能证实反应为可自发进行的放热过程,低温有利于吸附的进行,负的熵变说明吸附后体系的混乱度降低.动力学实验结果显示,吸附为快速过程.通过拟一级/二级动力学方程的拟合可知,HPD-100吸附水溶液中葛根异黄酮的过程遵循拟二级吸附动力学(相关系数大于0.99)规律.吸附速率随异黄酮初始浓度升高而显著降低.     

好氧颗粒污泥等温吸附甾体雌激素

为了研究好氧颗粒污泥对甾体雌激素E1、E2、EE2的吸附作用,通过摇瓶试验考察了吸附平衡时间及在不同温度下的等温吸附过程,对该过程进行了Freundlich方程和Langmuir方程拟合分析,并采用SEM观察好氧颗粒污泥结构.实验结果表明,吸附40min后基本达到平衡;吸附量随着温度的升高而减少,在20℃时,E1、E2、EE2最大吸附量分别为60.98、58.82、82.64μg/g;吸附过程符合Freundlich方程和Langmuir方程,其相关系数R2分别为0.93~0.99和0.92~0.99;吸附后好氧颗粒污泥表面及内部均发生了变化.     

对煤吸附甲烷的Lang muir方程的讨论

煤吸附甲烷量一般用Langmuir方程来表示 .Langmuir方程是用单分子层吸附模型推导出来的 ;在理论上 ,煤吸附甲烷不符合单分子层吸附模型 .由于煤吸附甲烷得到的吸附等温线都属于第Ⅰ类吸附等温线 ,所以可以用Langmuir方程来表示煤吸附甲烷量 ;同时 ,Langmuir方程使用方便 ,两个吸附常数a和b的物理意义明确 ,因而应用广泛     

对煤吸附甲烷的Langmuir方程的讨论

煤吸附甲烷量一般用Langmuir方程来表示.Langmuir方程是用单分子层吸附模型推导出来的;在理论上,煤吸附甲烷不符合单分子层吸附模型.由于煤吸附甲烷得到的吸附等温线都属于第Ⅰ类吸附等温线,所以可以用Langmuir方程来表示煤吸附甲烷量;同时,Langmuir方程使用方便,两个吸附常数a和b的物理意义明确,因而应用广泛。     

壳聚糖复合磁性生物炭吸附去除水中Cu(Ⅱ)的性能和机理

以粉碎松树枝粉末为原料高温热解制备生物炭,然后采用水热方法与Fe3O4和壳聚糖复合,制备复合吸附剂,并将其用于水中Cu(Ⅱ)的吸附去除。研究发现复合吸附剂可有效去除Cu(Ⅱ),反应1.5h后可达到吸附平衡,其最大平衡吸附量为74.83mg·g-1。对其吸附机理研究表明,Cu(Ⅱ)在复合吸附剂表面的吸附过程包括表面扩散、颗粒内部扩散和吸附平衡扩散三个阶段,其吸附反应动力学可采用准二级反应动力学方程拟合,吸附等温线符合Langmuir模型。对其反应热力学研究表明Cu(Ⅱ)在复合生物炭表面的吸附主要为物理吸附。     

天然斜发沸石对水中氨氮的吸附研究

研究了天然斜发沸石对废水中氨氮的吸附行为,比较了pH值、温度、氨氮浓度等条件对吸附性能的影响。对沸石的吸附等温线用Langmuir和Freundlich模型分析拟合表明,其吸附等温线更符合Langmuir模型;不同pH环境和不同温度下氨氮的吸附量比较表明,适宜的pH值和较低的温度有利于沸石具有较高的吸附量,在温度低于30℃、pH在4~8的范围内,沸石的吸附性量可达2 mg.g-1以上。     

煤渣作为人工湿地除磷基质的性能评价

通过静态吸附试验对煤渣的磷吸附动力学、热力学及等温线进行了模型拟合,并分析了pH值、离子强度和有机酸浓度对煤渣吸附磷的影响。拟合结果表明,煤渣对磷的吸附容量随着温度的升高而增加,Elovich方程和双常数方程对煤渣的磷吸附动力学过程拟合效果最好,煤渣吸附磷过程是一个自发的吸热过程,Freundlich方程对煤渣的等温磷吸附曲线拟合最好,Langmuir方程其次。影响因素试验表明：当4．28〈pH〈7．14时煤渣的吸附容量最小,在此范围外吸附容量均显著升高;离子强度的升高对磷的吸附有促进作用;草酸、柠檬酸和酒石酸3种有机酸随浓度的升高对煤渣磷吸附抑制作用增强,其中以草酸抑制最强。     

铁氧化物改性蛭石对Pb2+的吸附性能研究

将天然膨胀蛭石加入硝酸铁的碱性溶液中,制得铁氧化物改性蛭石。通过铁氧化物改性蛭石对Pb2+的吸附动力学和吸附热力学研究,了解其吸附机理。研究结果表明,铁氧化物改性蛭石对Pb2+的吸附动力学可用准二级速率方程描述;铁氧化物改性蛭石对Pb2+的吸附等温线均符合Langmuir和Freundlich方程;铁氧化物改性蛭石对Pb2+的吸附吉布斯自由能变ΔG0<0,吸附焓变ΔH0>0,表明吸附为自发的吸附过程,升温有利于吸附的进行,且吸附过程主要为物理吸附;铁氧化物改性蛭石在不同pH值下对Pb2+的吸附效果变化不明显。     

Kinetics and mechanism of the adsorption of methylene blue onto ACFs

The kinetics and mechanism of methylene blue (MB) adsorption onto activated carbon fibers (ACFs) have been studied.The effects of various experimental parameters, such as the initial MB concentration and the ACF mass, on the adsorption rate were investigated. Equilibrium data were fit well by a Freundlich isotherm equation. Adsorption measurements show that the process is very fast. The adsorption data were modeled using first- and second-order kinetic equations and intra-particle diffusion models. It was found that the first-order kinetic equation could best describe the adsorption kinetics. The adsorption process was found to be complex and controlled by both surface and pore diffusion with surface diffusion at the earlier stages, followed by pore diffusion at the later stages. The thermodynamic parameters △G0, △S0 and △H0, have been calculated. The thermodynamics of the MB-ACF system indicate that the adsorption process is spontaneous.     

CO2 isothermal adsorption models of coal in the Haishiwan Coalfield

Since the capacity of CO2 adsorption of coal is a key factor in coal and CO2 outbursts,an experimental study was carded out on CO2 isothermal adsorption with high-pressure volumetry with dry coal samples from the No.2 coal seam in the Haishiwan Coalfield.Four different equations (Langmuir,BET,D-R and D-A) were used to fit the experimental data.We discuss adsorption mechanisms.The results show that the amount of CO2 adsorption increases rapidly under low relative pressure,i.e.,the ratio of equilibrium pressure and saturated vapor pressure,which indicates that molecular layer adsorption or micropore filling may occur in coal.No clear equilibrium state was observed on the isothermal adsorption curves under relative pressure (P/P0) ranging from 0 to 0.8.The fitted results show that the accuracy of the D-A equation is highest with n=1.Micropores are more developed in coal by comparing the BET equation with a pressure mercury injection method on the surface area.The D-A equation (n=l) provides the best fit.By comparing the calculated specific surface area of the BET equation and the mercury intrusion method,it is found that micropore adsorption of CO2 occupies a dominant position.     

球形活性炭的制备及其对苯并噻吩的吸附研究

以122型弱酸性酚醛系阳离子交换树脂为炭前驱体,经过炭化和CO2活化,制备球形活性炭(SAC).利用热重分析、扫描电镜、红外光谱和低温N2吸附对材料进行表征.结果表明:制得的球形活性炭比表面积达到799.567 m2/g,孔容为0.969 cm3/g,对苯并噻吩的吸附硫容达到10.3mg/g.用Freundlich和Langmuir模型对吸附平衡数据进行拟合发现:球形活性炭对苯并噻吩的吸附更符合Freundlich模型,表明球形活性炭的吸附活性位不均匀分布;分别用准一级(PFO)、准二级(PSO)、修正的准n级(MPnO)和混阶(MOE)四种动力学速率方程对吸附动力学数据进行拟合,MPnO最适合描述球形活性炭吸附苯并噻吩的动力学过程.     

Methane adsorption behavior on coal having different pore structures

The adsorption of methane onto five dry coal samples was measured at 298 K over the pressure range from 0 to 3.5 MPa using a volumetric method. The isotherm data were fitted to the Langmuir and the Freundlich equations. The kinetic data were fitted to a pseudo second order equation, the linear driving force equation (LDF), and an intra-particle diffusion model. These results showed that higher methane adsorption is correlated with larger micro-pore volumes and specific surface areas. The adsorption was related to the narrow micro-pore size distribution when the previous two parameters are large. The kinetics study showed that the kinetics of methane adsorption onto these five dry coal samples followed a pseudo second order model very well. Methane adsorption rates are controlled by intra-particle diffusion. The faster the intra-particle diffusion, the faster the methane adsorption rate will be.     

含吡啶型聚苯乙烯阴离子树脂的合成及其对碘的吸附性能

通过对聚苯乙烯进行氯甲基化处理,获得了氯甲基化的聚苯乙烯树脂,然后把吡啶固载到树脂上得到含吡啶型聚苯乙烯阴离子树脂。通过FT-IR和元素分析方法研究了该树脂的结构并对其吸附碘的性能进行了研究,结果表明该树脂在中性水溶液中对碘的吸附能力比在酸性条件下强,碘在树脂中的吸附符合液膜扩散机理,吸附动力学方程符合拟一级和拟二级动力学方程;吸附热力学符合Langmuir吸附模型和Freundlich吸附模型。     

N-羧甲基壳聚糖对Ca2+,Fe2+的络合(吸附)及光谱分析

研究N-羧甲基壳聚糖(NCMC)对Ca^2 ，Fe^2 的吸附性能，探讨了时间、pH对吸附性质的影响。结果表明NCMC对Ca^2 ，Fe^2 的络合能力随pH的升高而增大。当pH=10时NCMC对Ca^2 的最大吸附量为0．6575mmol／g；pH=6时NCMC对Fe^2 的最大吸附量为2．3920mmol／g。NCMC对Fe^2 的吸附能力大于Ca^2 ，并通过IR和UV光谱证实了NCMC与Ca^2 ，Fe^2 的络合作用。     

D208树脂对肝素吸附过程的研究

以大孔强碱型离子交换树脂D208对肝素吸附行为为研究对象，对肝素的吸附平衡和吸附动力学进行研究。以Freundlich和Langmuir公式拟合25℃下的吸附等温线，研究结果表明：用Langmuir式拟合比较理想。D208树脂对肝素的离子交换过程为一级反应，交的速率常数为0．383h^-1。     

Adsorption of K+ from an aqueous phase onto an activated carbon used as an electric double-layer capacitor electrode

The adsorption capacity and absorption rate for electrolyte onto activated carbon are important parameters used to characterize activated carbon electric double-layer capacitor electrodes. In this paper the pore structure of typical commercial activated carbons, and various Mn-doped activated carbons prepared on a laboratory scale, are described. The pore structure was characterized by N2 adsorption/desorption isotherms. Isotherms for K+ adsorption onto these activated carbons from the aqueous phase were also obtained. The experimental, equilibrium K+ adsorption data were fitted to the Langmuir, Freundlich or Temkin equations. Adsorption of K+ onto the activated carbons was measured and plotted as a function of time. The adsorption kinetic data were modeled by either pseudo-first or pseudo-second order equations. The Elvoich equation, a liquid film diffusion and an intra-particle diffusion model were used to fit the kinetic data. The results indicate that the adsorption of K+ onto activated carbon is influenced by many factors including pore size distribution, specific surface area and the surface chemistry of the activated carbons. The Temkin equation best describes the equilibrium adsorption data. The pseudo-second order model exactly describes the whole adsorption process, which is controlled by both liquid film and intra-particle diffusion.