首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 671 毫秒
1.
The present work involves the study of Se(IV) adsorption onto granular activated carbon (GAC) and powdered activated carbon (PAC). The adsorbents are coated with ferric chloride solution for the effective removal of selenium. The physico-chemical characterization of the adsorbents is carried out using standard methods, e. g., proximate analysis, scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), thermo-gravimetric (TGA) and differential thermal analysis (DTA), etc. The FTIR spectra of the GAC and PAC indicate the presence of various types of functional groups, e. g., free and hydrogen bonded OH groups, silanol groups (Si-OH), alkenes, and CO group stretching from aldehydes and ketones on the surface of adsorbents. Batch experiments are carried out to determine the effect of various factors such as adsorbent dose (w), initial pH, contact time (t), and temperature (T) on the adsorption process. The optimum GAC and PAC dosage is found to be 10 g/L and 8 g/L, respectively, for Se(IV) removal with C0 = 100 mg/L. The percent removal of Se(IV) increases with increasing adsorbent concentration, while removal per unit weight of adsorbent increases with decreasing adsorbent concentration. Se(IV) adsorption onto both the GAC and PAC adsorbents is high at low pH values, and decreases with increased initial pH. The results obtained are analyzed by various kinetic models. The parameters of pseudo-first order, pseudo-second order kinetics, and Weber-Morris intra particle kinetics are determined. It is seen that the sorption kinetics of Se(IV) onto GAC and PAC can be best represented by the pseudo-second order kinetic model.  相似文献   

2.
The present study was aimed at removing cadmium ions from aqueous solution through batch studies using adsorbents, such as, granular activated carbon (GAC) and activated clay (A‐clay). GAC was of commercial grade where as the A‐clay was prepared by acid treatment of clay with 1 mol/L of H2SO4. Bulk densities of A‐clay and GAC were 1132 and 599 kg/m3, respectively. The surface areas were 358 m2/g for GAC and 90 m2/g for A‐clay. The adsorption studies were carried out to optimize the process parameters, such as, pH, adsorbent dosage, and contact time. The results obtained were analyzed for kinetics and adsorption isotherm studies. The pH value was optimized at pH 6 giving maximum Cd removal of 84 and 75.2% with GAC and A‐clay, respectively. The adsorbent dosage was optimized and was found to be 5 g/L for GAC and 10 g/L for A‐clay. Batch adsorption studies were carried out with initial adsorbate (Cd) concentration of 100 mg/L and adsorbent dosage of 10 g/L at pH 6. The optimum contact time was found to be 5 h for both the adsorbents. Kinetic studies showed Cd removal a pseudo second order process. The isotherm studies revealed Langmuir isotherm to better fit the data than Freundlich isotherm.  相似文献   

3.
In Germany, the gasoline additive methyl tert‐butyl ether (MTBE) is almost constantly detected in measurable concentrations in surface waters and is not significantly removed during riverbank filtration. The removal of MTBE from water has been the focus of many studies that mostly were performed at high concentration levels and centred in understanding the mechanisms of elimination. In order to assess the performance of conventional and advanced water treatment technologies for MTBE removal in the low concentration range further studies were undertaken. Laboratory experiments included aeration, granulated activated carbon (GAC) adsorption, ozonation and advanced oxidation processes (AOP). The results show that the removal of MTBE by conventional technologies is not easily achieved. MTBE is only removed by aeration at high expense. Ozonation at neutral pH values did not prove to be effective in eliminating MTBE at all. The use of ozone/H2O2 (AOP) may lead to a partly elimination of MTBE. However, the ozone/H2O2 concentrations required for a complete removal of MTBE from natural waters is much higher than the ozone levels applied nowadays in waterworks. MTBE is only poorly adsorbed on activated carbon, thus GAC filtration is not efficient in eliminating MTBE. A comparison with real‐life data from German waterworks reveals that if MTBE is detected in the raw water it is most often found in the corresponding drinking water as well due to the poor removal efficiency of conventional treatment steps.  相似文献   

4.
In the present study, the vine stem and modified vine stem were used as low cost adsorbents for the removal of acidic and basic dyes from aqueous solutions. A comparative study was also carried out with activated carbon obtained from vine stem and then the adsorption capacities of all adsorbents were evaluated by batch adsorption process. The effects of various adsorption parameters (initial pH, particle size, and contact time) were investigated. The modification of the vine stem with nitric acid increased its adsorption capacity for the basic dye. Both, vine stem and modified vine stem exhibited higher adsorption capacities than activated carbon. The adsorption capacities were found to be 322.58, 250, and 200 mg g?1 for modified, natural vine stem, and activated carbon, respectively. In the case of acidic dye, the pH strongly affected the adsorption capacity and the maximum dye uptake was observed at pH 2 for all adsorbents. The acidic dye adsorption was lower compared to basic dye on both biosorbents and activated carbon tested. The maximum acidic dye adsorption values (58.82 and 59.88 mg g?1) were obtained with the vine stem and activated carbon, respectively. In the case of lignocellulosic adsorbents, both surface charge and surface groups had main effect on the adsorption of basic dye, while adsorption mechanism in activated carbon was mainly through the physical adsorption. The results of comparative adsorption capacity of adsorbents indicated that vine stem or modified vine stem can be used as a low cost alternative to activated carbon in aqueous solution for basic dye removal.  相似文献   

5.
Adsorptive removal of EDTA (ethylenediaminetetraacetic acid) from aqueous solution was studied using steam pyrolyzed activated carbon. Rubber wood sawdust, obtained from a local timber facility at Kodangavila, Trivandrum, Kerala, India was used as the precursor for the production of the activated carbon. Batch adsorption experiments were employed to monitor and optimize the removal process. The experimental parameters, i. e., solution pH, agitation time, initial EDTA concentration and adsorbent dosage, affecting the adsorption of EDTA onto sawdust activated carbon (SDAC) were optimized. The inner core mechanism for the interaction between EDTA and SDAC, which resulted in the adsorption process, was also discussed. The change in amount of EDTA adsorbed onto SDAC and CAC (commercial activated carbon) was compared over a wide range of pH (2.0–8.0). The maximum removal of EDTA took place in the pH range of 4.0–6.0 for SDAC and 5.0–5.5 for CAC, which demonstrates the effectiveness of the former adsorbent. Kinetic as well as equilibrium studies were performed to determine the rate constant and adsorption capacity, respectively. The adsorption kinetic data was fitted with pseudo‐first‐order kinetics and the equilibrium data was shown to follow the Langmuir isotherm model. These observations explain the formation of a monolayer of EDTA on the surface of SDAC as confirmed by the slow approach to equilibrium after 4 h of contact time. The adsorption capacity of SDAC for the removal of EDTA was 0.526 mmol/g and is seen to be greater than that of CAC and other reported adsorbents (0.193–0.439 mmol/g). Finally, it is clear that the production of steam pyrolyzed activated carbon in the presence of K2CO3 greatly enhanced EDTA removal and resulted in a product with possible commercial value for wastewater treatment strategies.  相似文献   

6.
The removal of benzene, toluene, ethylbenzene, and xylene (BTEX) from aqueous solution by multi- and single-walled carbon nanotubes (MWCNTs and SWCNTs), hybrid carbon nanotubes (HCNTs) and nano-Fe was evaluated for a nanomaterials dose of 1 g/L and a BTEX concentration of 10 mg/L and pH 7. The equilibrium amount (q e ) (mg/g) removed by SWCNTs (B: 9.98, T: 9.96, E: 9.97, and X: 9.97 mg/g) was higher than for MWCNTs, HCNTs and nano-Fe in a c 0 of 10 mg/L and for a contact time of 10 min. The q e of total BTEX removed via SWCNTs was 39.89 mg/g. The order of uptake for SWCNTs is X > T = E > B, which is related to the increasing water solubility and the decreasing molecular weight of the compounds. The SWCNTs performed better for BTEX sorption than the MWCNTs, HCNTs and nano-Fe. The results of desorption study show that BTEX adsorbed on SWCNTs can easily be desorbed at 105 ± 2°C. It was concluded that recycling CNTs using heat improved the performance of the CNTs. For the first time, better adsorption performance was observed for recycled CNTs than for raw CNTs. SWCNTs are efficient BTEX adsorbents that could be used for cleaning up environmental pollution.  相似文献   

7.
Activated carbons prepared from sunflower seed hull have been used as adsorbents for the removal of acid blue 15 (AB‐15) from aqueous solution. Batch adsorption techniques were performed to evaluate the influences of various experimental parameters, e. g., temperature, adsorbent dosage, pH, initial dye concentration and contact time on the adsorption process. The optimum conditions for AB‐15 removal were found to be pH = 3, adsorbent dosage = 3 g/L and equilibrium time = 4 h at 30°C. The adsorption of AB‐15 onto the adsorbent was found to increase with increasing dosage. It was found from experimental results that the Langmuir isotherm fits the data better than the Freundlich and Temkin isotherms. The maximum adsorption capacity, Qm (at 30°C) was calculated for SF1, SF2, and SF3 as 75, 125 and 110 mg g–1 of adsorbent, respectively. It was found that the adsorption follows pseudo‐second order kinetics. The thermodynamic parameters such as ΔG°, ΔH°, and ΔS° were also evaluated. The activated carbons prepared were characterized by FT‐IR, SEM and BET analysis.  相似文献   

8.
The effects of various parameters such as initial concentration, adsorbent loading, pH, and contact time on kinetics and equilibrium of adsorption of Cd2+ metal ion from its aqueous solution by castor seed hull (CSH) and also by activated carbon have been investigated by batch adsorption experiments. The amount of adsorption increases with initial metal ion concentration, contact time, solution pH, and the loading of adsorbent for both the systems. Kinetic experiments indicate that adsorption of cadmium metal ion on both CSH and on activated carbon consists of three steps – a rapid adsorption of cadmium metal ion, a transition phase, and an almost flat plateau region. This has also been confirmed by the intraparticle diffusion model. The lumped kinetic results show that the cadmium adsorption process follows a pseudo‐second order rate law. The kinetic parameters including the rate constant are determined at different initial metal ion concentrations, pH, amount, and type of adsorbent, respectively. The Langmuir and Freundlich adsorption isotherm models are used to describe the experimental data. The Langmuir model yields a better correlation coefficient than the other model. A comparison of the monolayer adsorption capacity (qm) of CSH, activated carbon, and several other reported adsorbents has been provided. The value of separation factor (RL) calculated from the Langmuir equation also gives an indication of favorable adsorption of the metal ion. From comparative studies, it has been found that CSH is a potentially attractive adsorbent than commercial activated carbon for cadmium metal ion (Cd2+) removal.  相似文献   

9.
A vertical flow constructed wetland (VFCW) filled with natural zeolite had higher ammonium removal (82.4–94.0%) than another VFCW filled with volcanic rock (51.3–69.4%) treating piggery wastewater under any of three recirculation ratios. To reveal the underling reasons, physicochemical characteristics and ammonium‐oxidizing prokaryotes (AOPs) of two substrates were determined. The calculated maximum ammonium adsorption of zeolite (11.6 mg g?1) was remarkably higher than that of volcanic rock (0.21 mg g?1), mainly because the former contains two cationic binding crystalline species, and montmorillonite. Quantitative analyses indicated that ammonium‐oxidizing archaea (AOA) are the dominant AOP of zeolite and ammonium‐oxidizing bacteria (AOB) are the dominant AOP of volcanic rock respectively. Diversity and phylogenetic analysis further showed that both AOB and AOA communities were significantly different between two substrates. Nitrosospira‐like AOB (92.6%) and sediment/soil clade AOA (71.4%) were the main components of AOB and AOA in natural zeolite, whereas Nitrosomonas‐like AOB (76.1%) and water/sediment clade AOA (77.1%) dominated the AOB and AOA in volcanic rock. These results suggest that the substrates show high selectivity to AOP community. Thus, in addition to physicochemical characteristics, the AOP of substrates is very likely to affect ammonium removal in VFCWs.  相似文献   

10.
This study investigates potential occurrence, distribution, and sources of the newly added gasoline oxygenate, methyl‐tert‐butyl ether (MTBE) and the petroleum derivatives benzene, toluene, ethylbenzene, and xylenes called collectively, BTEX, in Jordan's heavily populated Amman–Zarqa Basin (AZB). It presents the first data on the levels of MTBE and BTEX in the aquifers of this basin. One hundred and seventy‐nine (179) groundwater wells were sampled near petrol service stations, oil refinery storage tanks, car wrecks, bus stations, and chemical industries at different locations in the basin. Headspace GC and purge and trap GC–MS were utilized to determine the target substances in the samples. Concentrations of BTEX varied between no‐detection (minimum) for all of them to 6.6 µg/L (maximum) for ethylbenzene. MTBE was found in few samples but none has exceeded the regulated levels; its concentrations ranged between no‐detection to 4.1 µg/L. However, though the contamination levels are very low they should be considered alarming.  相似文献   

11.
In India, the annual production of tea is ca. 857,000 tonnes, which is 27.4% of the total world production. The amount of tea factory waste (TFW) produced per annum after processing is ca. 190,400 tonnes. TFW can be used as a low cost adsorbent for the removal of toxic metals from the aqueous phase. An investigation was carried out to study the feasibility of the use of TFW as an adsorbent for the removal of the heavy metal, zinc. Equilibrium, kinetic and thermodynamic studies were reported. The straight line plot of log (qe–q) versus time t for the adsorption of zinc shows the validity of the Lagergren equation. The various steps involved in adsorbate transport from the solution to the surface of the adsorbent particles were dealt with by using a Weber‐Morris plot, qe versus t0.5 for the TFW. The rate controlling parameters, kid,1 and kid,2, were determined and it was found that the macro‐pore diffusion rate was much larger than micro‐pore diffusion rate. A batch sorption model, which assumes the pseudo‐second‐order mechanism, was used to predict the rate constant of sorption, the equilibrium sorption capacity and the initial sorption rate with the effect of initial zinc (II) ion concentration. Equilibrium data obtained from the experiments were analyzed with various isotherms, i. e., Freundlich, Langmuir, Redlich‐Peterson and Tempkin. The adsorption equilibrium was reached in 30 min and the adsorption data fitted well to all models. The maximum adsorption capacity of TFW for zinc (II) ions was determined to be 14.2 mg/g. The capacity of adsorption on Zn(II) increased with increasing temperatures and pH. The maximum uptake level of zinc was observed at pH of 4.2. The various thermodynamic parameters, i. e., ΔG°, ΔH° and ΔS°, were estimated. The thermodynamics of the zinc ion/TFW system indicated a spontaneous, endothermic and random nature of the process. The results showed that the TFW, which has low economical value, is a suitable adsorbent for the removal of zinc (II) ions from aqueous solutions.  相似文献   

12.
Field Treatment of MTBE‐Contaminated Groundwater Using Ozone/UV Oxidation   总被引：1，自引：0，他引：1  
Methyl‐tertiary butyl ether (MTBE) is often found in groundwater as a result of gasoline spills and leaking underground storage tanks. An extrapolation of occurrence data in 2008 estimated at least one detection of MTBE in approximately 165 small and large public water systems serving 896,000 people nationally (United States Environmental Protection Agency [U.S. EPA] 2008). The objective of this collaborative field study was to evaluate a small groundwater treatment system to determine the effectiveness of ultraviolet (UV)/ozone treatment in removing MTBE from contaminated drinking water wells. A pilot‐scale advanced oxidation process (AOP) system was tested to evaluate the oxidation efficiency of MTBE and intermediates under field conditions. This system used ozone as an oxidizer in the presence of UV light at hydraulic retention times varying from 1 to 3 min. MTBE removal efficiencies approaching 97% were possible with this system, even with low retention times. The intermediate t‐butyl alcohol (TBA) was removed to a lesser extent (71%) under the same test conditions. The main intermediate formed in the oxidation process of the contaminated groundwater in these studies was acetone. The concentrations of the other anticipated intermediates t‐butyl formate (TBF), isopropyl alcohol (IPA), methyl acetate (MAc), and possible co‐occurring aromatics (BTEX) in the effluent were negligible.  相似文献   

13.
Waste red mud and natural pumice/volcanic slag particles were surface modified and their selenium adsorption from waters was investigated. Acid activation/heat treatment of original red mud (ORM) particles significantly increased their micropore and external surface area and cumulative volume of pores. Iron oxide coating of pumice/slags and acid activation of ORM decreased their pHpzc values and increased surface acidity. Selenite/selenate adsorption on iron oxide surfaces and acid activated red mud (AARM) was very fast with approximately first‐order adsorption kinetics. Iron oxide coating of pumice/slag and acid activation of ORM particles significantly enhanced their selenite and selenate uptakes. Maximum Se adsorption capacities as high as 6.3 (mg Se/g adsorbent) were obtained by AARM. The extent of selenate uptakes by the surface modified particles was generally lower than those of selenite. Due to competition among Se species and other background water matrix for iron oxide adsorption sites, reduced selenite/selenate uptakes were found in natural water compared to single solute tests. Higher Se uptakes by iron oxide surfaces were found at pH 7.5 compared to pH 8.9, due to increased electrostatic repulsion among iron oxides and Se species at higher pH. The most effective adsorbents among the tested 17 different particles for Se uptake were AARM and iron oxide coated pumice. Se concentrations less than drinking water standards (5–10 µg/L) can be achieved by these particles. These low‐cost, natural, or recyclable waste particles appear to be promising adsorbents for Se removal after their surface modification.  相似文献   

14.
Methyl tert-butyl ether (MTBE), the widely used gasoline oxygenate, has been identified as a common ground water contaminant, and BTEX compounds (benzene, toluene, ethylbenzene, and xylenes) have long been associated with gasoline spills. Because not all instances of ground water contamination by MTBE and BTEX can be attributed to spills or leaking storage tanks, other potential sources need to be considered. In this study, used motor oil was investigated as a potential source of these contaminants. MTBE in oil was measured directly by methanol extraction and gas chromatography using a flame ionization detector (GC/FID). Water was equilibrated with oil samples and analyzed for MTBE, BTEX, and the oxygenate tert-amyl methyl ether (TAME) by purge- and-trap concentration followed by GC/FID analysis. Raoult's law was used to calculate oil-phase concentrations of MTBE, BTEX, and TAME from aqueous-phase concentrations. MTBE, TAME, and BTEX were not detected in any of five new motor oil samples, whereas these compounds were found at significant concentrations in all six samples of the used motor oil tested for MTBE and all four samples tested for TAME and BTEX. MTBE concentrations in used motor oil were on the order of 100 mg/L. TAME concentrations ranged from 2.2 to 87 mg/L. Concentrations of benzene were 29 to 66 mg/L, but those of other BTEX compounds were higher, typically 500 to 2000 mg/L.  相似文献   

15.
In this study, the adsorption of reactive red 120 (RR 120) on pistachio husk, and the modeling of the adsorption was investigated. Characterization of the pistachio husk was confirmed by Fourier transform infrared spectroscopy. The pHzpc of pistachio husk was found to be pH 8.5. Increasing the initial pH value decreased (p < 0.01) the amount of dye adsorbed. However, increasing the initial dye concentration from 50 to 900 mg/L at pH 1 increased (p < 0.01) the equilibrium dye uptake from 20.83 to 182.10 mg/g. Results indicated that this adsorbent had great potential for the removal of RR 120 dye. The logistic model was found to be the most suitable of the kinetic and equilibrium models tested to describe the adsorption of the dye. The parameters determined from the logistic model were well correlated with the initial dye concentration, and were seen to increase with the increasing initial dye concentration, but this was not observed from pseudo‐second order kinetics.  相似文献   

16.
Batch sorption technique was carried out for the removal of anionic dye Congo red (CR) from aqueous solution using raw rectorite (R‐REC) and organified rectorite (CTA+‐REC) modified by cetyltrimethylammonium bromide (CTAB) as adsorbents. The effects of organification degree of CTA+‐REC as well as the process parameters including the pH of dye solution, sorption time, and initial dye concentration on adsorption capacity for CR were investigated and the sorption kinetics was also evaluated. The results showed that the sorption behaviors of R‐REC and CTA+‐REC for CR followed pseudo‐second‐order kinetic model and the sorption equilibrium data perfectly obeyed the Langmuir isotherm. The thermodynamic parameters including entropy of sorption (ΔS0), enthalpy of sorption (ΔH0), and Gibbs free energy of sorption (ΔG0) were obtained and analyzed. Fourier transform infrared study revealed that a chemisorption process occurred between CR and CTA+‐REC. REC modified by cationic surfactants showed the higher adsorption capacities for CR compared to R‐REC and in theory would be used as an efficient and promising adsorbent for the removal of anionic dyes in wastewater treatment.  相似文献   

17.
Adsorption of reactive black 5 (RB5) from aqueous solution onto chitosan was investigated in a batch system. The effects of solution pH, initial dye concentration, and temperature were studied. Adsorption data obtained from different batch experiments were modeled using both pseudo first‐ and second‐order kinetic equations. The equilibrium adsorption data were fitted to the Freundlich, Tempkin, and Langmuir isotherms over a dye concentration range of 45–100 µmol/L. The best results were achieved with the pseudo second‐order kinetic and Langmuir isotherm equilibrium models, respectively. The equilibrium adsorption capacity (qe) was increased with increasing the initial dye concentration and solution temperature, and decreasing solution pH. The chitosan flakes for the adsorption of the dye was regenerated efficiently through the alkaline solution and was then reused for dye removal. The activation energy (Ea) of sorption kinetics was estimated to be 13.88 kJ/mol. Thermodynamic parameters such as changes in free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) were evaluated by applying the van't Hoff equation. The thermodynamics of reactive dye adsorption by chitosan indicates its spontaneous and endothermic nature.  相似文献   

18.
The increased accumulation of toxic pharmaceuticals and personal care products in the environment is a concern of worldwide relevance. Efficient technologies are needed to mitigate the level of such chemicals in natural waters. The suitability of multi‐walled carbon nanotubes (MWCNTs) to remove aqueous triclosan (a widely used anti‐microbial agent) was investigated in the present study. Tested operational parameters included the pH (3.0–11.0) value and the ionic strength (10?3, 10?2, and 10?1 M). Kinetic and thermodynamic studies were conducted at different initial concentrations (4, 8, and 10 mg/L) and temperatures (288, 298, and 308 K). Results showed higher triclosan adsorption at pH 3.0 (157.7 mg/g) than at pH 11.0 (103.9 mg/g). With an increase of ionic strength from 10?3 to 10?2 M, the adsorption capacity increased from 136.1 to 153.1 mg/g and from 80.8 to 105.8 mg/g at pH 3.0 and 10.0, respectively, while further increase of ionic strength to 10?1 M slightly reduced the triclosan adsorption to 149.9 and 94.7 mg/g due to the aggregation of MWCNTs. The Polanyi–Manes model (PMM) provided a best fitting of adsorption isotherms to the experimental data, and the kinetic process was well described by the pseudo second‐order kinetic model. The calculated thermodynamic parameters (ΔH0 = ?88.08 kJ/mol, ΔS0 = ?173.38 J/mol K) suggested that the adsorption of triclosan is spontaneous and exothermic in nature. The findings of the present work have significant implications for the removal of triclosan from aqueous solution with MWCNTs.  相似文献   

19.
This study investigates the potential use of activated carbon prepared from the peel of Cucumis sativa fruit for the removal of malachite green (MG) dye from simulated wastewater. The effects of different system variables, adsorbent dosage, initial dye concentration, pH, and contact time were investigated and optimal experimental conditions were ascertained. The results showed that when the amount of the adsorbent increased, the percentage of dye removal increased accordingly. Optimum pH value for dye adsorption was 6.0. Maximum dye was sequestered within 50 min of the start of every experiment. The adsorption of MG followed the pseudo‐second‐order rate equation and fits the Langmuir, Freundlich, Dubinin–Radushkevich (D–R), and Tempkin equations well. The maximum removal of MG was obtained at pH 6 as 99.86% for adsorbent dose of 1 g/50 mL and 25 mg L?1 initial dye concentration at room temperature. Activated carbon developed from the peel of C. sativa fruit can be an attractive option for dye removal from diluted industrial effluents since test reaction made on simulated dyeing wastewater showed better removal percentage of MG.  相似文献   

20.
Using batch method, the adsorption of thallium(I) ions from aqueous solutions on eucalyptus leaves powder, as a low cost adsorbent, was studied. The effect of various modification of considered adsorbent on the adsorption percentage of Tl(I) is an important feature of this study. The results showed that the unmodified and acidic modified adsorbent are the poor adsorbents for the Tl(I) ions while basic modified adsorbent is a suitable adsorbent. Also, the effect of some experimental conditions such as solution initial pH, agitation speed, contact time, sorbent dosage, temperature, particle size, and thallium initial concentration was studied. The results showed that the adsorption percentage depends on the conditions and the process is strongly pH‐dependent. The satisfactory adsorption percentage of Tl(I) ions, 81.5%, obtained at 25 ± 1°C. The equilibrium data agreed fairly better with Langmuir isotherm than Freundlich and Temkin models. The value of qm that was obtained by extrapolation method is 80.65 mg g?1. Separation factor values, RL, showed that eucalyptus leaves powder is favorable for the sorption of Tl(I). The negative values of ΔH0 and ΔS0 showed that the Tl(I) sorption is an exothermic process and along with decrease of randomness at the solid–solution interface during sorption, respectively.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号