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1.
This study reports the potential ability of non-living biomass of Cabomba caroliniana for biosorption of Cr(III) and Cr(VI) from aqueous solutions. Effects of contact time, biosorbent dosage, pH of the medium, initial concentration of metal ion and protonation of the biosorbent on heavy metal–biosorbent interactions were studied through batch sorption experiments. Cr(III) was sorbed more rapidly than Cr(VI) and the pH of the medium significantly affected the extent of biosorption of the two metal species differently. Surface titrations showed that the surface of the biosorbent is positively charged at low pH while it is negatively charged at pH higher than 4.0. Protonation of the biosorbent increased its capacity for removal of Cr(III), while decreasing that of Cr(VI). FT-IR spectra of the biosorbent confirmed the involvement of –OH groups on the biosorbent surface in the chromium removal process. Kinetic and equilibrium data showed that the sorption process of each chromium species followed pseudo second-order kinetic model and both Langmuir and Freundlich isothermal models. A possible mechanism for the biosorption of chromium species by non-living C. caroliniana is suggested.  相似文献   

2.
The treatment of radioactive liquid waste containing organic compounds was always a cause for concern to radioactive waste management facilities because the processes available are expensive and difficult to manage. Biosorption has been studied as a new process in simulated wastes as an alternative to treating them. Among the potential biomass, the coconut fiber has very attractive features that allow the removal of radionuclides using a low-cost biosorbent. The aim of this study was to evaluate the capacity of coconut fiber to remove uranium, americium, and cesium from real radioactive liquid organic waste. Experiments with the biosorption of these radionuclides in coconut fiber were made including (1) preparation, activation, and characterization of biomass and (2) biosorption assays. The biomass was tested in raw and activated form. Biosorption assays were performed, adding the biomass to real waste solutions. The solutions contain natural uranium, americium-241, and cesium-137. The contact times and the concentrations range were varied. The radioisotopes remaining concentration in the solutions was determined by inductively coupled plasma optical emission spectrometry and gamma spectrometry. The results were evaluated by maximum experimental sorption capacity and isotherm and kinetics ternary models. The highest sorption capacity was observed with the activated coconut fiber, with values of 2 mg/g of U (total), 70E?06 mg/g of Am-241 and 40E?09 mg/g of Cs-137. These results suggest that biosorption with activated coconut fiber can be applied in the treatment of radioactive liquid organic wastes containing uranium, americium-241, and cesium-137.  相似文献   

3.
The biosorption of ammoniacal nitrogen (N-NH4 +) from aqueous solutions by dead biomass of brown seaweed Cystoseira indica and Jatropha oil cake (JOC), which is generated in the process of biodiesel recovery from its seeds, was studied under diverse experimental conditions. The N-NH4 + biosorption was strictly pH dependent, and maximum uptake capacity of C. indica (15.21 mg/g) and JOC (13.59 mg/g) was observed at initial pH 7 and 3, respectively. For each biosorbent–N-NH4 + system, kinetic models were applied to the experimental data to examine the mechanisms of sorption and potential rate-controlling steps. The generalized rate model and pseudo-second-order kinetic models described the biosorption kinetics accurately, and the sorption process was found to be controlled by pore and surface diffusion for these biosorbents. Results of four-stage batch biosorber design analysis revealed that the required time for the 99 % efficiency removal of 40 mg/L N-NH4 + from 500 L of aqueous solution were 76 and 96 min for C. indica and JOC, respectively. The Fourier transform infrared spectroscopy analysis before and after biosorption of ammonium onto C. indica and JOC revealed involvement of carboxylic and hydroxyl functional groups.  相似文献   

4.
Biofilms wasted from biotrickling filters was dried and used as biosorbent for Cd(II) removal from aqueous solutions. The adsorption condition and effect, adsorption isotherms and kinetics of Cd(II) removal were investigated, and the effects of competitive metal ions on Cd(II) removal were also examined. Results showed that the dry waste biofilms reached the maximum adsorption capacity of 42 mg/g of Cd(II) at 25 °C for 120 min when the initial concentration of Cd(II) and their pH were 50 mg/L and 6.0, respectively. Under these conditions, the removal efficiency of Cd(II) reached to 89.3% when the biosorbent dosage was 2.0 g/L. The Langmuir isotherm model correlated with the isotherm data better than the Freundlich isotherm model, and the pseudo-second-order model fitted the kinetic data better than the pseudo-first-order model. These results indicated that the adsorption was monolayer accompanied with chemical adsorption. In the presence of other metal ions, divalent metal ions of Ca and Zn inhibited the performance of Cd(II) biosorption significantly, while Na(I), K(I) and Fe(III) which had a higher or lower valence than Ca(II) affected slightly when containing 50 mg/L Cd(II), 0.5 g/L adsorbent dosage and pH 6.0. The analyses of scanning electron microscopy and Fourier transform infrared spectroscopy illuminated that the biosorbent had porous structures and the amide group was the majorly responsible for Cd(II) removal. Dry biofilms were novel sorbents for effective removal Cd(II), and it could be reused and recycled if necessary.  相似文献   

5.
The Pb(II) and Ni(II) biosorption of a fungal biomass isolated from mine drainage of metal-processing industries in Balya (Bal?kesir province, Turkey) was optimized using a response surface methodology by altering parameters such as pH, initial metal concentration, contact time and biosorbent dosage. This strain was shown to be highly similar to Penicillium sp. Furthermore, zeta potential measurements and Fourier transform infrared spectroscopy were performed to understand the adsorption mechanism. A Box–Behnken design with 29 experiments was used to evaluate the interactions between independent variables. The results showed that the fungal biomass isolated from the metal mine drainage could have a significant environmental impact through the biosorption of Pb(II) and Ni(II) in waters polluted with heavy metals, particularly in the drainage from metal mines. The maximum removal values were 76 and 47 % at pH 4.5 for both Pb(II) and Ni(II), with 123 and 33 mg/L initial metal concentrations, 65 and 89 min contact times and 0.2 and 1.6 g/L biosorbent, respectively.  相似文献   

6.
The present study reports on the preliminary investigation of three low-cost natural materials with respect to their chromium(VI) removal efficiency from contaminated water. The tested materials were reed, in milled and chopped form, compost, and dewatered sludge from a municipal wastewater treatment plant. The chromium(VI) removal capacity of the aforementioned materials was investigated by simulating the physicochemical conditions prevailing in a stormwater outfall flowing into the Asopos River in Inofyta, Central Greece. Thus, batch and column experiments were carried out using solutions of 3–5 mg/L chromium(VI) and pH value 8.5 ± 0.5. The results showed that the tested materials were capable of removing 3 mg/L chromium(VI), however by allowing different contact times for each material. The chromium(VI) removal kinetics were studied through batch experiments, and reed was found to be the most efficient material. Therefore, at a second series of batch and up-flow column experiments, the effect of the liquid-to-solid ratio, pH, and contact time on chromium(VI) removal using chopped reed was investigated. Chromium(VI) removal took place through both reduction and adsorption mechanisms, while the released soluble organic matter from reed seemed to favor the reduction mechanism. As a result, reed is a potential biosorbent capable of treating heavily chromium(VI)-contaminated water flows, although a high mass of reed is required for a treatment process, such in the case of the stormwater discharged into Asopos River.  相似文献   

7.
Hexavalent chromium has been proved to be the reason of several health hazards. This study aimed at evaluating the application of pomegranate seeds powder for chromium adsorption (VI) from aqueous solution. Chromium adsorption percentage (VI) increased with increasing the adsorbent dosage. Chromium adsorption capacity (VI), at pH = 2 and 10 mg/L initial metal concentration, decreased from 3.313 to 1.6 mg/g through increasing dosage of adsorbent from 0.2 to 0.6 g/100 ml. The adsorption rate increased through increase in chromium initial concentration (VI). However, there was a removal percentage reduction of chromium (VI). Chromium adsorption kinetics by different models (pseudo-first-order, modified pseudo-first-order, pseudo-second-order, Elovich, intraparticle diffusion, Boyd kinetic) was investigated as well. Studies on adsorption kinetic indicated that the experimental data were matched by pseudo-second-order model (R 2 = 0.999) better. Obtained results demonstrated the pomegranate seeds can be used as an effective biomaterial and biosorbent for hexavalent chromium adsorption from aqueous solutions.  相似文献   

8.
In this study, dried anaerobic digested sludge (DADS) was utilized to remove 4-chlorophenol (4-CP) from aqueous solutions. Batch biosorption experiments were carried out to investigate the effects of physicochemical parameters such as pH, contact time, biosorbent dosage, and initial concentration. Artificial neural network (ANN) was then used to predict the removal efficiency of the process. The comparison between predicted and experimental results provided a high degree of determination coefficient (R2 = 0.98), indicating that the model could predict the biosorption efficiency with reasonable accuracy. Biosorption data were successfully described by the Freundlich isotherm and pseudofirst-order model. The Weber–Morris kinetic model indicated that intraparticle diffusion was not the only rate-controlling step, and other mechanisms may be involved in the biosorption process. The optimum pH was detected to be 3 for DADS. By increasing contact time and biosorbent dosage, the removal efficiency of 4-CP increased. Also, a decreasing trend was observed when initial concentrations were increased. The findings suggested that the results predicted by ANN are very close to the experimental values, and DADS as an available adsorbent can efficiently remove 4-CP from aqueous solutions.  相似文献   

9.
Arsenic is a ubiquitous element in the environment and occurs naturally in both organic and inorganic forms. Under aerobic condition, the dominant form of arsenic in waters is arsenate, which is highly mobile and toxic. Arsenic poisoning from drinking water remains a serious world health issue. There are various standard methods for arsenic removal from drinking waters (coagulation, sorption, ion-exchange reactions or methods of reverse osmosis) and alternative methods, such as biosorption. Biosorption of arsenic from natural and model waters by native or chemically modified (with urea or ferric oxyhydroxides) plant biomass prepared from sawdust of Picea abies was studied. The kinetic of the adsorption process fitted well the pseudo second order adsorption model and equilibrium was achieved after 2 h. The results showed that biosorption was well described by both Langmuir and Freundlich isotherms. The maximum biosorption capacity of the sawdust modified with ferric oxyhydroxides, evaluated by Langmuir adsorption model, was 9.259 mg/g, while the biosorption capacity of unmodified biosorbent or biosorbent modified with urea was negligible. The adsorption capacity is comparable to results published by other authors, suggesting that the prepared chemically modified biosorbent has potential in remediation of contaminated waters.  相似文献   

10.
A novel biosorbent synthesized from Ficus racemosa leaves based on the treatment using NaOH was applied for removal of Acid Blue 25 from aqueous solution. The synthesized biosorbent was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller analysis. NaOH treatment was demonstrated to remove lignin content from the biomass and to induce the development of significant pores. Batch experiments were performed to evaluate the effect of important operating parameters such as pH (range of 2–10), biosorbent dose (range of 1–10 g/L), contact time (range of 0–5 h), initial dye concentration (range of 50–400 mg/L) and temperature (range of 293–323 K) on the extent of removal of Acid Blue 25. The established optimum conditions were pH of 2, biosorbent dose of 4 g/L, contact time of 3 h and temperature of 323 K, yielding maximum removal of dye. Pseudo-second-order model was found to best fit the kinetic data. Langmuir and Temkin isotherm models were found to best fit the equilibrium data. The obtained thermodynamic parameters confirmed endothermic and spontaneous nature of adsorption. The study established the utility of novel biosorbent for removal of Acid Blue 25 with higher adsorption capacities (83.33 mg/g) as compared to the more commonly used adsorbents. Desorption-adsorption  studies conducted for seven cycles indicated potential reusability of synthesized biosorbent for the treatment of dye effluents.  相似文献   

11.
The objective of this study was to investigate the biosorption of an azo dye (Methylene blue) by a wetland phytomass (Typha angustata) under post-phytoremediation scenario. Thus, the phytomass was used without any chemical modification. The batch adsorption experiments were conducted to evaluate the effects of contact time and temperatures (25–45 °C) on the adsorption of methylene blue (MB) from aqueous solution by cattail phytomass (CP). More than 80 % of MB dye was removed from the aqueous solution within first 10 min of the experiment. Langmuir isotherm was modeled to describe the monolayer adsorption of MB dye (R 2 = 0.995) with the maximum adsorption capacity of 8.1 mg/g at 25 °C. Pseudo-second-order kinetic model adequately described the kinetics of absorption process (R 2 = 0.999). The adsorption of MB on the cattail phytomass was a spontaneous and endothermic process that was governed by chemisorption. Hence, CP could be applied as a potential low cost biosorbent to treat dyeing wastewater.  相似文献   

12.
This paper investigates the potential of alginate-immobilised Chlorella sorokiniana for removing Cu2+, Ni2+ and Cd2+ ions from drinking water solutions. The effects of initial metal concentrations, contact times and temperatures on the biosorptions and removal efficiencies of the tested metals were investigated at initial pH values of 5, and pH effects were studied within the range of 3–7. When studying the effects of initial metal concentrations, the highest experimental removal yields achieved for Cu2+, Ni2+ and Cd2+ ions were 97.10, 50.94 and 64.61 %, respectively. The maximum biosorption capacities obtained by the Langmuir isotherm model for the biosorptions of Cu2+, Ni2+ and Cd2+ ions by alginate-immobilised C. sorokiniana were found to be 179.90, 86.49 and 164.50 mg/g biosorbent, respectively. The experimental data followed pseudo-second-order kinetics. At an initial metal concentration of 25 mg/L, immobilised algae could be used in at least 5 successive biosorption–desorption cycles. SEM and EDS analyses revealed that the metals bonded to the biosorbent. Bi- and multi-metal systems of Cu2+, Ni2+ and Cd2+ were investigated at initial metal concentrations of 30, 50 and 100 mg/L. The removal of Cd2+ as well as Ni2+ in such systems was negatively affected by the presence of Cu2+. The removal efficiency for Cu2+ in multi-metal systems decreased by 5–7 %, whilst in the cases of Cd2+ and Ni2+ the efficiencies decreased by up to 30 %. Nevertheless, the results obtained show that alginate-immobilised C. sorokiniana can efficiently remove the metals tested from polluted drinking water sources.  相似文献   

13.
The biosorption of chromium (VI) ions from aqueous solutions by two adsorbents viz. mango and neem sawdust was studied under a batch mode. An initial pH of 2.0 was most favorable for chromium (VI) removal by both the adsorbents. The results obtained for the final concentration of chromium (VI) and chromium (DI) at a pH range of 2–8 indicated that a combined effect of biosorption and reduction was involved in the chromium (VI) removal specially when the pH value is lower than 3. The maximum loading capacity was calculated from adsorption isotherms by applying the Langmuir model and found to be higher for neem sawdust (58.82 mg/g). Evaluation of experimental data in terms of biosorption kinetics showed that the biosorption of chromium (VI) by neem sawdust followed pseudo second-order kinetics. Therefore, the rate limiting step may be chemical sorption or chemisorption. The efficiency of this process was examined in using tannery wastewater contaminated with chromium (VI) ions in column mode.  相似文献   

14.
Surface modification of two algal biomasses, Nizimuddinia zanardini and Stoechospermum marginatum, using 4-phenyl-3-thiosemicarbazide ligand was performed to investigate the consequences on the adsorption of heavy metals from aqueous solution. Stabilization of amino group of 4-phenyl-3-thiosemicarbazide on the surface of biomasses was confirmed using Fourier transform infrared spectroscopy. Chemical modification was found to exert significant positive effects on biosorption. Adsorption capacities for Pb(II), Cd(II) and Cr(VI) using modified N. zanardini were observed to be 19.3, 16.75 and 15.75 mg/g, respectively, compared to 17.48, 14.18 and 11.85 mg/g for raw N. zanardini biomass. Also, adsorption of Pb(II), Cd(II) and Cr(VI) by the modified S. Marginatum was found to be 17.54, 15.62 and 14.77 mg/g, respectively, in comparison with that of the raw biomass which were 16.86, 12.9 and 11.2 mg/g. The obtained results of the equilibrium adsorption were studied through different isotherm models of Langmuir, Freundlich and Temkin, where the Langmuir model was observed to agree well with the results. Prevalent kinetic models including pseudo-second order and intra-particle diffusion were applied, and the pseudo-second order was found to describe the adsorption kinetics data adequately. Intra-particle model was also utilized in order to show penetration of metal ions, where it was realized that the biosorption took place in two or three steps including film diffusion, molecular diffusion and chemical reaction.  相似文献   

15.
Pannonibacter phragmitetus BB was utilized to treat hexavalent chromium [Cr(VI)] contaminated water. Cr(VI) concentration of the contaminated water (pH 10.85) was 534 mg/L. With the inoculum size ranging from 1 to 20 %, P. phragmitetus BB completely reduced Cr(VI) within 27 h when the initial medium concentration exceeded 20 g/L. The lag time of bio-reduction by Cr(VI)-induced cells was 24 h, which was longer than the non-Cr(VI)-induced cells. Under the agitation condition, an obvious bio-reduction lag phase existed and Cr(VI) was completely reduced within 24 h. However, the lag phase was not observed under the static condition, Cr(VI) was reduced continuously after inoculation and Cr(VI) was completely reduced after 27 h incubation. The main chromium components after Cr(VI) reduction were Cr(OH)3, Cr2O3 and CrCl3. The results of this study are fundamentally significant to the application of P. phragmitetus BB in the treatment of Cr(VI) contaminated water.  相似文献   

16.
The present study explores the effectiveness of Saraca indica leaf powder, a surplus low value agricultural waste, in removing Pb ions from aqueous solution. The influence of pH, biomass dosage, contact time, particle size and metal concentration on the removal process were investigated. Batch studies indicated that maximum biosorption capacity for Pb was 95.37% at the pH 6.5. The sorption process followed the first order rate kinetics. The adsorption equilibrium data fitted best to both Langmuir and Freundlich isotherms. Morphological changes observed in scanning electron micrographs of untreated and metal treated biomass confirmed the phenomenon of biosorption. Fourier transform infrared spectroscopy of native and exhausted leaf powder confirmed lead biomass interactions responsible for sorption. Acid regeneration was tried for several cycles with a view to recover the sorbed metal ion and also to restore the sorbent to its original state. The findings showed that Saraca indica leaf powder can easily be envisaged as a new, vibrant, low cost biosorbent for metal clean up operations.  相似文献   

17.
The biosorption characteristics of Cd(II) and Cu(II) ions from aqueous solutions obtained using submerged aquatic plant (Myriophyllum spicatum) biomass were investigated in terms of equilibrium, kinetics, thermodynamics, and cation competition. Langmuir and Freundlich models were applied to describe the biosorption isotherm of metal ions by M. spicatum biomass and isotherm constants considering the most important parameter, pH. The variation of sorption isotherm constants showed pH dependence. The Langmuir and Freundlich models fitted the equilibrium data well. The maximum biosorption capacity (q m) of M. spicatum biomass was determined to be 29.07 mg/g for the Cd(II) ion at pH 5.0 and 12.12 mg/g for the Cu(II) ion at pH 6.0. Chi square analysis showed that the Freundlich model fitted the equilibrium data better than the Langmuir isotherm. Competition of Cd(II) and Cu(II) in a binary solution showed that the Langmuir monolayer capacity of Cd(II) decreased from 29.07 mg/g with only Cd(II) in solution to 12.02 mg/g in the presence of Cu(II). Kinetics results showed that the biosorption processes of both metal ions followed the pseudo-second-order kinetics well. The calculated thermodynamic parameters (?G 0, ?H 0, and ?S 0) showed that biosorption of Cd(II) and Cu(II) ions onto M. spicatum biomass was feasible, spontaneous, and endothermic in nature. Fourier transform infrared spectroscopy spectrum analysis revealed that Cd(II) and Cu(II) sorption was mainly ascribed to carboxyl, hydroxyl, amine, and C–N groups in M. spicatum.  相似文献   

18.
In this study, nickel ions adsorption from zinc ingot factory wastewater by brown algae (Sargassum glaucescens) and chitosan/polyvinyl alcohol nano-fiber membrane at continuous system was studied. The continuous process included a biosorption reactor and fixed-bed reactor that were optimized by predicting two batch steps with response surface modeling, based on the Box–Behnken in the novel approach. Nano-biosorbent characterized by scanning electron microscopy, Brunauer–Emmett–Teller and Fourier transform infrared spectrometer analysis. Maximum biosorption in this continuous system was at pH 6, biosorbent doses 8 g L?1 S. glaucescens and 0.48 g L?1 nano-fiber. The study of the reaction rate showed kinetic data best fitted by pseudo-first-order model with R 2 > 0.95 than pseudo-second-order and intraparticle diffusion models. Biosorption equilibrium data were performed using Langmuir isotherm and Freundlich isotherm, Langmuir isotherm fit better with equilibrium data.  相似文献   

19.
Adsorption kinetic and equilibrium studies of two reactive dyes, namely, Reactive Red 31 and Reactive Red 2 were conducted. The equilibrium studies were conducted for various operational parameters such as initial dye concentration, pH, agitation speed, adsorbent dosage and temperature. The initial dye concentration was varied from 10 - 60 mg/L, pH from 2–11, agitation speed from 100–140 rpm, adsorbent dosage from 0.5 g to 2.5 g and temperature from 30 °C -50 °C respectively. The activated carbon of particle size 600 μm was developed from preliminary tannery sludge. The dye removal capacity of the two reactive red dyes decreased with increasing pH. The zero point charge for the sludge carbon was 9.0 and 7.0 for the two dyes, respectively. Batch kinetic data investigations on the removal of reactive dyes using tannery sludge activated carbon have been well described by the lagergren plots. It was suggested that the Pseudo second order adsorption mechanism was predominant for the sorption of the reactive dyes onto the tannery sludge based carbon. Thus, the adsorption phenomenon was suggested as a chemical process. The adsorption data fitted well with Langmuir model than the Freundlich model. The maximum adsorption capacity(q0) from Langmuir isotherm were found to have increased in the range of 23.15–39.37 mg/g and 47.62–55.87 mg/g for reactive dyes reactive red 31 and reactive red 2, respectively.  相似文献   

20.
A total of 422 bacterial isolates were obtained from the lead (Pb) ore in north-eastern Iran. The Pb tolerances of these strains were studied using microbroth serial dilution approach and 35 strains could grow up to 3250 ppm Pb concentration. Of these strains, 10 of them represented qualitatively high levels of Pb adsorption and were selected for quantitative studies. Strain AS2 which is phylogenetically related to genus Bacillus showed the highest level of Pb remediation. The effects of different factors, including pH, initial Pb concentration, temperature and inoculum size, were studied on the remediation process. Pb remediation capacity was reached at 74.5 mg/g (99.5 % of initial Pb) at pH 4.5, temperature 30 °C, inoculum size 1.0 % (v/v) and an initial Pb concentration of 500 ppm after 24 h. Pb desorption capacity of strain was 66 %. The novel isolate could remove 98 % of Pb from the contaminated industrial wastes after 24 h. Pb uptaking to the cell surface was proven using scanning electron microscopic micrograph and energy-dispersive X-ray spectroscopy analysis. Most Pb removal efficiency was observed in the active cell culture as compared to the inactive cell and extracellular polymeric substances. The novel strain represents a good candidate for removal of environmental anthropogenic Pb pollutions.  相似文献   

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