改性花生壳吸附水中Cr6+的研究

研究了改性花生壳对Cr6 的吸附作用,并探讨了溶液的pH值、Cr6 初始浓度、吸附时间、温度及改性花生壳用量等因素对Cr6 吸附效果的影响.结果表明,在温度为33℃、改性花生壳用量为1.0 g、20 mg·L-1的Cr6 溶液50 mL、溶液的pH值为2.0、振荡吸附时间为120 min的条件下,Cr6 的吸附去除率达到了98.4%.     

硝酸改性花生壳对Pb2+的吸附研究

以花生壳为原料、HNO3为改性剂,对花生壳进行改性制备吸附剂,并研究了其吸附水中Pb2 的性能.结果表明,在2.0 g花生壳中加入体积分数为10%的HNO3溶液25 mL、控制温度80℃、搅拌3 h,得到改性的花生壳;用此改性花生壳吸附Pb2 的最佳条件为:0.20 g改性花生壳、97.5 mg·L-1的Pb2 溶液25 mL、pH值5.0、搅拌吸附60 min,在此条件下吸附率可达97%;吸附后的花生壳用0.5 mol·L-1的HCl溶液再生,重复使用2次对Pb2 的吸附率在92%以上;同时,比较了改性花生壳和未改性花生壳对Pb2 的吸附性能,未改性花生壳对Pb2 的吸附率为87%,改性花生壳对Pb2 的吸附率为96%,通过HNO3改性使花生壳的吸附性能得到提高.     

花生壳活性炭对Cu~(2+)的吸附性能研究

以花生壳为原料,磷酸为活化剂制备花生壳活性炭,采用高分辨电子扫描电镜(SEM)对花生壳活性炭进行了表征。从热力学和动力学的角度,研究了花生壳活性炭对Cu2+的吸附行为。热力学研究表明:花生壳活性炭对Cu2+的吸附符合Langmuir等温吸附方程,该吸附是自发吸热过程。动力学研究表明:花生壳活性炭对Cu2+的吸附符合二级反应动力学方程反应特征,颗粒内扩散为主要控速步骤。     

花生壳活性炭对水中Cu2+的吸附研究

以氢氧化钾为活化剂,高温碳化花生壳制备活性炭,并用于吸附水中铜离子。通过单因素实验,探索了花生壳活性炭对水中Cu²⁺离子的吸附性能,在最优条件(活性炭投加量0.6 g、40℃、2 h)下,对初始质量浓度30 mg/L的50 mL溶液进行了吸附实验。结果表明,Cu²⁺离子去除率达96.57%。活性炭吸附水中铜离子的过程符合准二级动力学模型。     

农业废弃物香芋柄对含Mn2+废水的吸附

以废弃香芋柄作为新型生物吸附剂,通过静态吸附实验,研究了pH、温度、吸附时间、Mn2+初始浓度等因素对香芋柄吸附Mn2+的影响,分析了吸附过程的热力学、动力学和等温吸附规律. 结果表明,溶液初始pH=4,香芋柄用量6 g/L,30℃下吸附60 min,溶液中Mn2+吸附去除率达90.79%以上,吸附容量高达18.16 mg/g. 应用Langmuir和Freundlich模型描述香芋柄对Mn2+的吸附过程,结果显示Freundlich吸附等温线拟合效果更好. 吸附动力学实验数据符合准二级动力学模型. 计算得到热力学参数DG<0, DH>0, DS>0,表明该吸附过程是自发和吸热的过程.     

花生壳对抗生素的吸附特性研究

研究了生物质花生壳对溶液中头孢拉定的吸附特性和吸附机理,考察了不同条件对头孢拉定吸附效果的影响.结果表明,25℃、pH为5左右、吸附剂用量为1.0g·L-1和头孢拉定初始质量浓度为60 mg·L-1的条件下,吸附平衡时间为90min、吸附率为98.21%.在一定范围内吸附剂用量和共存离子对花生壳吸附头孢拉定影响不显著;花生壳对头匏啦定的吸附符合2级动力学模型,由粒子内扩散模型可知花生壳对头孢拉定的吸附属于单层吸附.     

花生壳生物炭的改性及其吸附Pb2+性能研究

以花生壳为原料热解制备生物炭,并分别采用NaOH和KMnO₄进行改性,经表征发现改性后生物炭微观结构较为疏松、孔径变小、稳定性增强,NaOH改性花生壳生物炭（AB）和KMnO₄改性花生壳活性炭（MnB）的比表面积分别增至花生壳生物炭（B）的3.178倍和5.065倍,以KMnO₄作为改性剂时,锰氧化物成功地固定在生物炭上,B、AB和MnB的零电荷点（pH_PZC）分别为2.193、2.888和2.466。探究改性前后生物炭对Pb²⁺的吸附性能发现：B、AB和MnB吸附Pb²⁺的适宜pH值分别为4.5~6.5、5.5~6.5和5.0~6.5,达到相同Pb²⁺去除率时,生物炭用量MnB 2+的吸附平衡时间较B吸附Pb²⁺的吸附平衡时间（1 080 min）分别缩短了180和480 min。通过吸附动力学模型和等温线模型分析可知,3种生物炭吸附Pb²⁺的过程均受化学吸附控制,吸附速率MnB>AB>B,AB和MnB的最大理论吸附量分别是53.19和80.65 mg/g,分别提高至B的1.38倍和2.10倍。     

灭活酿酒酵母对水中Ni2+的吸附去除

以灭活酿酒酵母菌为生物吸附剂,研究吸附剂对水中的镍离子吸附。考察了溶液初始pH、菌体投加量、温度等因素对吸附镍离子的影响,并对灭活酿酒酵母菌吸附镍离子的吸附动力学和吸附等温线进行了研究。通过动电电位分析,表明实验用的灭活酿酒酵母等电点介于3～4之间。当溶液的pH为7,吸附能力较好,灭活酵母菌对镍离子吸附量可达128.33 mg/g。随着酵母菌投加量增加,其对镍离子吸附量也随之下降。对灭活酵母吸附Ni~(2+)的数据进行动力学分析,发现灭活酵母菌对Ni~(2+)的吸附符合准二级动力学吸附模型,吸附量理论值q_(cal)为133.33 mg/g。对酵母菌吸附镍离子的等温吸附数据进行分析,表明灭活酵母菌对Ni~(2+)的吸附符合Langmuir等温模型。在30℃时,酵母菌对镍离子的饱和吸附量可达83.33 mg/g。     

花生壳对Pb^2＋的吸附特性研究

以花生壳为吸附物质,研究了吸附pH值,吸附时间对3种不同产地花生壳吸附水溶液中Pb^2＋的影响,同时进行解吸研究。研究结果表明：在25℃,Pb^2＋的质量浓度为30mg／L条件下得出最佳吸附pH值为4．5．吸附平衡时间为30min。花生壳对Ph^2＋的吸附符合准二级动力学模型,Freundlich模型能很好的拟合等温吸附试验数据。吸附后的花生壳在600℃灼烧灰化回收,Pb^2＋的回收率达到93％以上。     

硼酸-微波改性花生壳对Cd~(2+)的吸附特性

采用硼酸-微波二次改性的方法对农业废弃物花生壳进行改性,获得改性生物吸附材料。利用扫描电子显微镜(SEM)、傅里叶红外光谱(FTIR)等手段分析了改性花生壳的结构和成分,并研究了不同因素对改性花生壳吸附性能的影响。结果表明,在花生壳投加量为4 g/L,pH为6～7,30℃的条件下,Cd⁽²⁺⁾的去除率可以达到97.2%,最大吸附量为21.77 mg/L。通过相关模型对动力学和吸附等温曲线的拟合,证明花生壳对Cd(2+)的去除率可以达到97.2%,最大吸附量为21.77 mg/L。通过相关模型对动力学和吸附等温曲线的拟合,证明花生壳对Cd⁽²⁺⁾的吸附是单分子层吸附,吸附过程主要受化学吸附的控制。     

Adsorption of uranium on phosphoric acid-activated peanut shells

ABSTRACT

Phosphoric acid-activated peanut shells (PS) were prepared by hydrothermal treatment at 200–800 °C and denoted as peanut shell-activated carbons (PACs). The PACs were characterized as adsorbent for removing U(VI) from aqueous solutions. The U(VI) adsorption on PACs follows the pseudo-second-order kinetic equation and the Langmuir model. The adsorption capacity depends on solution pH and ionic strength and PAC-800 exhibits the highest adsorption capacity. The increasing U(VI) adsorption could be attributed to C = OOH groups and delocalized π electrons as sorption sites by surface complexation and ion exchange. Therefore, PACs as economic adsorbents could potentially remove U(VI) from aqueous solutions.     

高温焙烧底泥吸附重金属Mn2+和Ni2+的动力学与热力学研究

制备了高温焙烧底泥作为吸附剂,并对底泥焙烧前后的表征(SEM、FTRI、XRD、BET)进行研究与分析.采用静态吸附试验来研究高温焙烧底泥吸附废水中重金属Mn2+和Ni2+的吸附动力学与热力学的特性并确定吸附机理.结果表明:对高温焙烧底泥吸附的数据进行拟合且符合Langrnuir和Freundlich吸附等温方程,但拟合效果更好的符合Freundlich吸附等温方程,表明吸附介于单层与多层之间.在高温焙烧底泥对Mn2和Ni2的吸附阶段用Lagergren伪一级吸附动力学方程和Lagergren伪二级吸附动力学方程进行拟合,其结果表明吸附过程遵循Lagergren伪二级吸附动力学方程,表明以化学吸附为主,对Mn2、Ni2+的平衡吸附量分别为5.2083、3.6563 mg/g.由热力学参数(△S、△H和△G)表明:高温焙烧底泥对Mn2+和Ni2+的吸附均为吸热过程.     

花生壳对Pb~(2+)的吸附特性研究

以花生壳为吸附物质,研究了吸附pH值,吸附时间对3种不同产地花生壳吸附水溶液中Pb2+的影响,同时进行解吸研究。研究结果表明:在25℃,Pb2+的质量浓度为30mg/L条件下得出最佳吸附pH值为4.5,吸附平衡时间为30min。花生壳对Pb2+的吸附符合准二级动力学模型,Freundlich模型能很好的拟合等温吸附试验数据。吸附后的花生壳在600℃灼烧灰化回收,Pb2+的回收率达到93%以上。     

Adsorption of selected toxic metals by modified peanut shells

The objective of this study was to modify peanut shells to enhance their adsorptive properties toward the metal ions cadmium (Cd²⁺), copper (Cu²⁺), nickel (Ni²⁺), lead (Pb²⁺) and zinc (Zn²⁺). Milled peanut shells were initially washed with water or 0.1 N NaOH or left unwashed. Following these treatments or lack of treatment, the shells were either left unmodified or modified by a heat treatment in the presence of either 1.0 M phosphoric acid or 0.6 M citric acid. Modified peanut shells were evaluated either for adsorption efficiency or for adsorption capacity using the five metal ions listed above. Adsorption efficiencies and capacities were compared with efficiencies and/or capacities for the commercial chelating or cation exchange resins Amberlite 200, Amberlite IRC‐718, Duolite GT‐73, and carboxymethylcellulose. For the adsorption efficiencies of individual metal ions, modified peanut shells met or exceeded the adsorption values for cadmium, copper, nickel or zinc ions compared with the commercial resins Duolite GT‐73 and carboxymethylcellulose. In a solution containing all five metal ions, modified peanut shells met or exceeded the adsorption efficiencies for cadmium, copper and lead ions compared with Duolite GT‐73, Amberlite IRC‐718 and carboxymethylcellulose. Adsorption capacities of modified peanut shells met or exceeded the adsorption capacity of Duolite GT‐73 for lead ions only. Citric or phosphoric acid‐modified peanut shells showed a preference for Cu²⁺ and Pb²⁺ and appear promising as potentially inexpensive adsorbents for selected metal ions. © 2001 Society of Chemical Industry     

过氧化氢改性花生壳对铬(Ⅵ)的吸附

用过氧化氢改性花生壳吸附六价铬,考察了改性花生壳投加量、吸附温度和铬的初始浓度等影响。结果表明,当花生壳的投加量为1.0 g,吸附时间为2 h,温度为60℃,50 mL铬的初始浓度为50 mg/L的吸附效果为最佳,吸附率为80%。红外分析表明,过氧化氢改性花生壳吸附铬的官能团主要为羟基、羧基,包含物理吸附和化学吸附。     

Adsorption of Zn2+ and Cu2+ onto sulphate and phosphate-modified bentonite

The modification of bentonite with sulphate and phosphate increased the cation exchange capacity (CEC) and adsorption of Cu²⁺ and Zn²⁺ but decreased the specific surface area (SSA). Phosphate modified bentonite had the highest adsorption capacity for both metal ions. The Fourier transformed infrared spectra indicated the bonding of sulphate and phosphate bentonite with sulphate and phosphate by the hypochromic and hyperchromic shifts are typical of physisorption and chemisorption mechanisms. Phosphate and sulphate were adsorbed through inner-sphere and outer-sphere complex formation. The isotherms were better fitted by the Langmuir model than the Freundlich model.     

Adsorption of Fe+3 and Mn+2 from Ground Water onto Maize Cobs Using Batch Adsorber and Fixed Bed Column

Abstract

The removal of iron and manganese from ground water is an important step for producing safe drinking water. A detailed investigation of the sorption of iron and manganese from ground water onto maize cobs is reported. This work deals with determination of adsorption equilibrium isotherms, kinetic, and fixed bed column studies. Results of Freundlich and Langmiur parameters revealed the favorability of maize cobs for adsorption of iron and manganese ions. Kinetic studies were carried out using from ground water samples (El‐Mina Governorate, Egypt). From the kinetic studies, a model is proposed to determine the external mass transfer (Ks) which can be correlated by the following equation Ks =A (mass)^B. where A and B are constants. During the fixed bed column studies, the effect of process variables such as bed height, flow rate, initial concentration, and percentage breakthrough has been investigated. A simplified design method, namely, the bed depth service time (BDST) model has been applied to the experimental data and the results of this analysis are presented. The mechanism of the metal ion sorption on maize cobs was also investigated. Both the calorific values and differential thermal analysis (DTA) data proved that the loaded maize cobs can be used as solid fuel. Pretences of iron and manganese salts catalyze the thermal decomposition reaction toward more flammable gases, which increase their calorific values. The loaded maize cobs are considered a new potential source for energy conversion.     

凹凸棒石对水中Mn~(2+)的吸附特性研究

通过静态试验,对凹凸棒石吸附去除水中Mn2+的特性进行了研究,重点讨论了焙烧和酸化处理对吸附的影响。结果表明,凹凸棒石对水中Mn2+吸附过程可以班厄姆公式进行拟合。弗兰德利希吸附等温式可以更好地描述Mn2+在凹凸棒石上的吸附过程。当焙烧温度在105～400℃,焙烧处理对凹凸棒石吸附去除Mn2+的影响不明显,当焙烧温度在500℃时,凹凸棒石对Mn2+的吸附去除率显著降低。凹凸棒石对Mn2+的吸附去除率随着酸化浓度的增加先减小而后增大,在HCl浓度为4 mol·L-1时达到最低。     

柠檬酸改性花生壳对水中重金属Cu、Pb、Cd和Cr的吸附特性研究

用柠檬酸对粒状花生壳进行改性,考察了改性粒状花生壳的投加量、吸附反应时间、重金属初始浓度等对水中Cu、Pb、Cd和Cr吸附量的影响,探讨了改性粒状花生壳的等温吸附及吸附动力学特性。结果表明,准二级吸附动力学方程可较好地模拟Cu、Pb、Cd和Cr等4种重金属在改性粒状花生壳上的吸附动力学行为;Langmuir模型能相对更好地拟合改性粒状花生壳对4种重金属的等温吸附过程,Cu、Pb、Cd和Cr的理论最大吸附量分别为11.88,20.70,7.82,7.35 mg/g。改性粒状花生壳与Pb的结合力最强,对Pb的吸附容量远大于其它3种重金属。