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1.
2.
ABSTRACT

The solid residue of the cold press oil extraction from prickly pear (Opuntia ficus indica L.) fruit seeds was evaluated as a low-cost biosorbent for biosorption of Cr(VI) from aqueous solutions. Batch experiments were conducted as a function of initial pH, contact time, biosorbent dose, initial Cr(VI) concentration, and temperature. Biosorption was highly pH-dependent and found to be maximum at pH 1.0. Langmuir and Freundlich equations fitted very well with experimental data. The maximum monolayer adsorption capacity was 19.61 mg/g at 298 K and pH 1.0. Biosorption kinetics was controlled by the pseudo-second-order model. Thermodynamic parameters indicated that biosorption of Cr(VI) was a spontaneous, favorable and endothermic process. The activation energy was found to be 40.68 kJ.mol?1.  相似文献   

3.
BACKGROUND: The removal of methylene blue from aqueous solution was studied using softstem bulrush (Scirpus tabernaemontani Gmel.) as the biosorbent. The effects of various parameters including contact time, biosorbent dosage, ionic strength and solution pH on the biosorption were investigated. RESULTS: The sorption capacity increased with an increase in biosorbent dosage and a decrease in ionic strength. The equilibrium time was found to be 240 min for full equilibration. Pseudo‐first‐order, pseudo‐second‐order, Bangham equation and intraparticle diffusion models were applied to fit the kinetic data, and the results showed that the sorption process followed the pseudo‐second‐order model. Equilibrium data conformed to Langmuir and Redlich–Peterson isotherm models, with a maximum monolayer biosorption capacity of 53.8 mg g?1 for the Langmuir isotherm at 18 °C. The value of ΔG was estimated to be ? 29.24 kJ mol?1, indicating the spontaneous nature of the biosorption. The biosorption process was strongly pH‐dependent and favourable at alkaline pH. CONCLUSION: Softstem bulrush, which is readily available and inexpensive, could be employed as a promising biosorbent for the removal of dye. Copyright © 2008 Society of Chemical Industry  相似文献   

4.
Biosorption of Acid Red 57 (AR57) on to Neurospora crassa was studied with variation of pH, contact time, biosorbent and dye concentrations and temperature to determine equilibrium and kinetic models. The AR57 biosorption was fast and equilibrium was attained within 40 min. Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherm models were applied to experimental equilibrium data for AR57 biosorption at various temperatures. The equilibrium data fitted very well to all the equilibrium models in the studied concentration range of AR57. Maximum biosorption capacity (qmax) of AR57 on to N. crassa was 2.16 × 10?4 mol g?1 at 20 °C. The kinetics of biosorption of AR57 were analyzed and rate constants were derived. The overall biosorption process was best described by a pseudo‐second‐order kinetic model. The changes in Gibbs free energy, enthalpy and entropy of biosorption were also evaluated for the biosorption of AR57 on to N. crassa. The results indicate that the biosorption was spontaneous and exothermic in nature. Copyright © 2006 Society of Chemical Industry  相似文献   

5.
《分离科学与技术》2012,47(1):192-211
Abstract

In this study, the biosorption of Basic Blue 9 (BB9) dye from aqueous solutions onto a biomass of Euphorbia rigida was examined by means of the initial biosorbate concentration, biosorbent amount, particle size, and pH. Biosorption of BB9 onto E. rigida increases with both the initial biosorbate concentration and biosorbent amount, whereas decreases with the increasing particle size. The experimental data indicated that the biosorption isotherms are well‐described by the Langmuir equilibrium isotherm equation at 20, 30, and 40°C. Maximum biosorption capacity was 3.28×10?4 mol g?1 at 40°C. The biosorption kinetics of BB9 obeys the pseudo‐second‐order kinetic model. The thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated to estimate the nature of biosorption. These experimental results have indicated that E. rigida has the potential to act as a biosorbent for the removal of Basic Blue 9 from aqueous solutions.  相似文献   

6.
In this study, the feasibility of using modified plantain peel to remove 2,6-dichlorophenol from iaqueous solutions was investigated under batch mode. The effects of physical factors such as initial 2,6-dichlorophenol concentration, contact time, biosorbent particle size, biosorbent dosage and temperature on the removal process were evaluated. The results showed that biosorption of 2,6-dichlorophenol was dependent on these factors. The equilibrium biosorption data were analyzed by the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich (D-R) adsorption isotherm models. The four tested isotherm models provided good fits to the experimental data obtained at 30°C; however, the Freundlich isotherm model provided the best correlation (R2 = 0.9874) of the experimental data. The maximum monolayer biosorption capacity (Q max ) was found to be 14.25 mg/g. The biosorption kinetics data of 2,6-dichlorophenol were analyzed by pseudo-first-order, pseudo-second-order, Elovich, intraparticle diffusion, and liquid film diffusion models. The five kinetic models fitted well to the biosorption kinetic data; however, the pseudo-second-order kinetic model gave the best fit when the biosorption mechanism was controlled by film diffusion. Thermodynamic quantities such as standard Gibbs free energy (ΔG°), standard enthalpy (ΔH°), standard entropy change of biosorption (ΔS°), and activation energy (Ea) were evaluated, and it was found that the biosorption process was spontaneous, feasible, endothermic in nature and of dual nature, physisorption and chemisorption; however, the physisorption process was dominant. Therefore, modified plantain peel has potential for application as an effective bioadsorbent for removal of 2,6-dichlorophenol from aqueous solution.  相似文献   

7.
The coating of silk yarn with microcrystalline chitosan (MCCh) was carried out using the ultrasonic‐assisted method at a pulsed wave frequency of 80 kHz, which only had a slight impact on the yarn as measured by changes in Young's modulus and percentage of elongation compared with untreated silk. A significant enhancement of lac dye uptake onto MCCh‐coated silk yarn compared with the untreated silk was observed. The rate of dye uptake at different temperatures onto silk yarn coated with MCCh was investigated. It was found that the adsorption rate constant and diffusion coefficient both increased with increasing temperature, as a result of a diffusion kinetically controlled process with a diffusion activation energy of 9.40 kJ mol?1. This suggests that dye adsorption on silk yarn coated with MCCh is a physisorption process. The free energy change (?G), enthalpy change (?H) and entropy change for dye adsorption were also determined, and the negative values of ?G and ?H obtained indicated that the lac dye adsorption process is both spontaneous and exothermic.  相似文献   

8.
《分离科学与技术》2012,47(15):2293-2301
The capacity of Ganoderma lucidum biomass for biosorption of selenium (IV) ions from aqueous solution was studied in a batch mode. In this study the effects of operating parameters such as solution pH, adsorbent dosage, initial metal concentration, contact time, and temperature were investigated. The adsorption capacity of G. lucidum was found to be 126.99 mg g?1. The biosorption follows pseudo-first order kinetics and the isotherms fit well to both Langmuir and Freundlich isotherm models. Isotherms have been used to determine thermodynamic parameters of the process, that is, free energy, enthalpy, and entropy changes. Furthermore, the biosorbent was characterized by scanning electron microscopy and FT-IR analysis. FT-IR analysis of fungal biomass shows the presence of amino, carboxyl, hydroxyl, and carbonyl groups, which were responsible for the biosorption of selenium(IV) ions. The results indicated that the biomass of G. lucidum is an efficient biosorbent for the removal of selenium (IV) ions from aqueous solutions.  相似文献   

9.
A comprehensive feasibility study on adsorption of Cu(II) and a water‐soluble nitrazine yellow (NY) dye by chitosan‐montmorillonite (CS‐MMT) hydrogel as the biosorbent was investigated as a function of biosorbent dosage, initial concentration, pH, temperature, and the presence of salts. Box–Behnken methodology was applied to optimize the adsorption experiments. Maximum adsorption values were determined as 132.74 mg/g and 144.41 mg/g at pH = 5.0, for Cu(II) and NY dye, respectively. Equilibrium isotherms of Langmuir and Freundlich were analyzed by the non‐linear regression model. The equilibrium data were well described by Freundlich model and the adsorption process well fitted pseudo‐second order kinetics. The enthalpy change of adsorption (ΔH°) were calculated as ?3.78 kJ/mol and ?5.75 kJ/mol for Cu(II) and NY dye, respectively, indicating that the adsorption processes were exothermic. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43664.  相似文献   

10.
《分离科学与技术》2012,47(7):1044-1054
A biomass derived from plant A. nilotica (leave) has been used for efficient removal of trivalent arsenic (As(III)) from aqueous media. The experiments were carried out to study the effects of different parameters i.e., biomass dosage, As(III) concentration, pH, temperature, and contact time. The equilibrium biosorption data were analyzed by the Langmuir and Freundlich isotherm models and satisfactorily both isotherm models could be fitted well. The biosorption mean free energy based on the D-R isotherm model was calculated in the range of 7.50–8.21 kJ mol?1. The data of thermodynamic parameters [enthalpy (ΔH°), Gibbs free energy (ΔG°), and entropy (ΔS°)] were identified that biosorption of As(III) onto studied biomass was spontaneous, feasible, and exothermic under the optimum experimental conditions. Kinetic estimations based on the experimental data demonstrated that the biosorption of As(III) followed the pseudo-second-order kinetics. The studied biomass was successfully applied for the removal of As(III) from contaminated groundwater samples of Jamshoro district.  相似文献   

11.
《分离科学与技术》2012,47(6):997-1004
Equilibrium, thermodynamic, and kinetic studies on the biosorption of Cu(II) using biomass, Trichoderma viride were carried out. The biosorbent was characterized by Fourier transform infrared spectroscopy and Scanning Electron Microscopy. The Langmuir and Freundlich isotherm models were applied to describe the biosorption process. The influence of pH, the biomass dosage, the contact time, the initial metal ion concentration, and the temperature of the solution on the biosorption was studied. The maximum Cu(II) biosorption was attained at pH 5. The equilibrium data were better fit by the Langmuir isotherm model than by the Freundlich isotherm. The maximum biosorption capacity of T. viride biomass was found to be 19.6 mg/g for Cu(II). The kinetic studies indicated that the biosorption of Cu(II) followed the pseudo-second-order model. The calculated thermodynamic parameters, Gibbs-free energy (ΔGo), enthalpy (ΔHo), and entropy (ΔSo) showed that the biosorption of Cu(II) onto T. viride biomass was spontaneous and endothermic. It can be concluded that the T. viride biomass has the potential as an effective and low-cost biosorbent for Cu(II) removal from aqueous solutions.  相似文献   

12.
《分离科学与技术》2012,47(1):112-123
The feasibility of using eggshells as a low-cost biosorbent for the removal of Direct Red 28 (DR 28) from aqueous solutions was studied in batch and dynamic flow modes of operation. The effect of biosorption process variables such as particle size, solution pH, initial dye concentration, contact time, temperature, feed flow rate, and bed height were investigated. Both the Langmuir and Freundlich isotherm models exhibited excellent fit to the equilibrium biosorption data. Optimum pH (6.0), particle size (<250 µm), initial dye concentration (50 mg g?1), temperature (313 K), and contact time (240 min) gave maximum monolayer biosorption capacity of 69.45 mg g?1 which was higher than those of many sorbent materials. Pseudo-second-order kinetic model depicted the biosorption kinetics accurately. Thermodynamic study confirmed the spontaneous and endothermic nature of the biosorption process. Breakthrough time increased with increase in the bed height but decreased with increase in flow rate. Overall, batch and continuous mode data suggest the applicability of eggshells as an environment friendly and efficient biosorbent for removal of DR 28 from aqueous media.  相似文献   

13.
《分离科学与技术》2012,47(16):2550-2562
ABSTRACT

The complete removal of Pb(II) was achieved by intact Pseudomonas putida cells. The biosorption isotherm exhibited Langmuirian behaviour and followed pseudo-second-order rate kinetics. The standard Gibbs free energy change (?G°) for the biosorption of Pb(II) ions was found to be ?26.4 kJ mol?1, attesting to a chemisorption process. Thermolysis of P. putida cells improved the Pb(II) binding capacity by around 27%. All the four components tested, namely DNA, protein, polysaccharide and lipid, were found to contribute to the uptake of Pb(II) ions. The possible mechanisms of Pb(II) binding by P. putida have been delineated.  相似文献   

14.
BACKGROUND: In this study, the capability of low‐cost, renewable and abundant marine biomass Posidonia oceanica (L.) for adsorptive removal of anionic and non‐ionic surfactants from aqueous solutions have been carried out in batch mode. Several experimental key parameters were investigated including exposure time, pH, temperature and initial surfactant concentration. RESULTS: It was found that the highest surfactant adsorption capacities reached at 30 °C were determined as 2.77 mg g?1 for anionic NaDBS and as 1.81 mg g?1 for non‐ionic TX‐100, both at pH 2. The biosorption process was revealed as a thermo‐dependent phenomenon. Equilibrium data were well described by the Langmuir isotherm model, suggesting therefore a homogeneous sorption surface with active sites of similar affinities. The thermodynamic constants of the adsorption process (i.e. ΔG°, ΔH° and ΔS°) were respectively evaluated as ? 8.28 kJ mol?1, 48.07 kJ mol?1 and ? 42.38 J mol?1 K?1 for NaDBS and ? 9.67 kJ mol?1, 95.13 kJ mol?1 and ? 174.09 J mol?1 K?1 for TX‐100. CONCLUSION: Based on this research, valorization of highly available Posidonia oceanica biomass, as biological adsorbent to remove anionic and non‐ionic surfactants, seems to be a promising technique, since the sorption systems studied were found to be favourable, endothermic and spontaneous. Copyright © 2007 Society of Chemical Industry  相似文献   

15.
Tobacco hairy roots (THR) were used to evaluate its potential for the biosorption and removal of malachite green (MG) from aqueous solutions. A 32 full factorial design was applied to study the effects of pH and THR concentration on the biosorption capacity. Under the optimal conditions (pH of 7.0 and THR concentration of 1?g?L?1), dye removal efficiency was around 92%. Experimental data obtained from kinetic studies demonstrated good concordance with the pseudo-second-order model. Equilibrium studies were developed and the data were evaluated by Langmuir, Freundlich, and Sips models, being the Sips model the most adequate (maximum biosorption capacity of 277.2?mg?g?1). Thermodynamically, the biosorption of MG on THR proved to be endothermic, spontaneous, and favorable. Desorption was feasible under acidic conditions and the biosorbent could be reused three times. THR was tested in simulated effluent and the removal percentage was 87%, demonstrating that this material is a promising biosorbent which can be used to treat colored wastewaters.  相似文献   

16.
Multidye biosorption of Sunset yellow (SY), Eosin yellow (EY) and Indigo carmine (IC) dyes onto chemically modified biomass of brown alga Sargassum glaucescens was studied. Principal component-wavelet neural network (PC-WNN) was applied for the simultaneous determination of anionic dye concentrations in ternary solutions. Experimental parameters were optimized using response surface methodology (RSM) with a Doehlert design. The optimal biosorption conditions were identified as biosorbent dosage 0.2 g L?1, pH 3, and time 25 min. The maximum total biosorption capacity was 0.102 mmol g?1. The Hill isotherm was the most suitable adsorption models in single and ternary systems. Scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) analysis confirmed possible interactions between biosorbent surface and dye molecules.  相似文献   

17.
The synergistic effect of 1‐phenyl‐3‐methyl‐4‐benzoyl‐pyrazalone‐5 (HPMBP, HA) and di‐(2‐ethylhexyl)‐2‐ethylhexylphosphonate (DEHEHP, B) in the extraction of rare earths (RE) from chloride solutions has been investigated. Under the experimental conditions used, there was no detectable extraction when DEHEHP was used as a single extractant while the amount of RE(III) extracted by HPMBP alone was also low. But mixtures of the two extractants at a certain ratio had very high extractability for all the RE(III). For example, the synergistic enhancement coefficient was calculated to be 9.35 for Y3+, and taking Yb3+ and Y3+ as examples, RE3+ is extracted as RE(OH)A2.B. The stoichiometry, extraction constants and thermodynamic functions such as Gibbs free energy change ΔG (?17.06 kJ mol?1), enthalpy change ΔH (?35.08 kJ mol?1) and entropy change ΔS (?60.47 J K?1 mol?1) for Y3+ at 298 K were determined. The separation factors (SF) for adjacent pairs of rare earths were calculated. Studies show that the binary extraction system not only enhances the extraction efficiency of RE(III) but also improves the selectivity, especially between La(III) and the other rare earth elements. Copyright © 2006 Society of Chemical Industry  相似文献   

18.
Powdered waste sludge (PWS) obtained from a paint industry wastewater treatment plant and pretreated with 1% H2O2 was used for biosorption of Zn(II) ions from aqueous solution. The effects of operating conditions, pH, temperature, agitation speed, PWS particle size, Zn ion and PWS concentrations on the extent of Zn ion biosorption were investigated in batch experiments. The optimum pH resulting in maximum Zn ion biosorption was found to be pH = 5, since Zn ions precipitated in the form of Zn(OH)2 at pH levels above 5. The rate and extent of Zn ion biosorption increased with temperature between 25 and 50 °C, although biosorption was not strongly sensitive to temperature variations since the activation energy was low at 4.5 kcal mol?1. Biosorbent particle size had a significant effect on Zn ion biosorption, yielding high percentage Zn removals at small particle sizes (Dp < 100 µm) or large surface areas of PWS. Agitation speed also considerably affected the extent of Zn ion removal, and should be above 150 rpm in order to obtain a high rate. The extent of Zn ion biosorption was also affected by the initial Zn ion and PWS concentrations. At constant biosorbent (PWS) concentration, percentage Zn ion removal decreased, but the biosorbed Zn concentration increased with increasing initial Zn ion concentrations. However, at constant initial Zn concentrations, percentage Zn removal increased, but the biosorbed Zn ion concentration decreased with increasing adsorbent (PWS) concentration. With a maximum Zn ion biosorption capacity of 168 mg g?1 powdered waste sludge was proven to be an effective biosorbent compared to other biosorbents. Copyright © 2006 Society of Chemical Industry  相似文献   

19.
The removal of cadmium from aqueous solution by sorption on Aeromonas caviae particles was investigated in a well‐stirred batch reactor. Equilibrium and kinetic experiments were performed at various initial bulk concentrations, biomass loads and temperatures. Biosorption equilibrium was established in about 1 h and biosorption was well described by the Langmuir and Freundlich biosorption isotherms. The maximum biosorption capacity was found as 155.32 mg Cd(II) g?1 at 20 °C. The obtained sorption capacity is appreciably high for most experimental conditions; so A caviae may be considered as a suitable biosorbent for the removal of cadmium. Moreover, the sorption rate of cadmium onto A caviae particles was particularly sensitive to initial bulk concentration and solid load. A detailed analysis was conducted, examining several diffusion (external and intraparticle) kinetic models in order to identify a suitable rate expression. The results are discussed and indicate that biosorption of cadmium is a complex process that is described more correctly by more than one model. Copyright © 2004 Society of Chemical Industry  相似文献   

20.
《分离科学与技术》2012,47(10):1456-1462
The biosorption behavior of lanthanum and cerium ions from aqueous solution by leaf powder of Pinus brutia was separately studied in a batch system as a function of initial pH, contact time, initial metal ion concentration, temperature, and adsorbent amount. The uptake of lanthanum and cerium was increased when the initial pH of the solution was increased. Thermodynamic parameters such as standard enthalpy (ΔH°), entropy (ΔS°) and free energy (ΔG°) were calculated and the results indicated that biosorption was endothermic and spontaneous in nature. The biosorption of lanthanum and cerium on powdered leaf of Pinus brutia was investigated by the Freundlich, Langmuir, and D-R isotherms. The results show that lanthanum and cerium adsorption can be explained by the Langmuir isotherm model and monolayer capacity was found as 22.94 mg g?1 for lanthanum and 17.24 mg g?1 for cerium. Desorption of lanthanum and cerium was studied using 0.5 M HNO3 solution. The results suggested that powdered leaf of Pinus brutia may find promising applications for the recovery of lanthanum and cerium from aqueous effluents.  相似文献   

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