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硝酸改性花生壳对Pb2+的吸附研究 总被引:8,自引:0,他引:8
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. 相似文献
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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. 相似文献
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花生壳生物炭的改性及其吸附Pb2+性能研究 总被引:1,自引:0,他引:1
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(pHPZC)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。 相似文献
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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。 相似文献
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《应用化工》2022,(7):1736-1740
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。 相似文献
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ABSTRACTPhosphoric 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. 相似文献
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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. 相似文献
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Srinath Chamarthy Chung W Seo Wayne E Marshall 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2001,76(6):593-597
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 相似文献
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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. 相似文献
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《分离科学与技术》2012,47(5):943-959
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. 相似文献
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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。 相似文献
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