In the present study we reported the feasibility of the Anethum graveolens as biosorbent to remove Pb(II) from aqueous solutions. Anethum graveolens was characterized by scanning electron microscopy and elemental anal...In the present study we reported the feasibility of the Anethum graveolens as biosorbent to remove Pb(II) from aqueous solutions. Anethum graveolens was characterized by scanning electron microscopy and elemental analysis. The ability of Anethum graveolens to adsorb Pb(II) was investigated by using batch adsorption procedure. The effects such as pH, contact time, adsorbate concentration and biosorbent dosage on the adsorption capacity were studied. The experimental data were analysed using various adsorption kinetic models viz., the pseudo-first and second-order equations, Bangham’s equation, intraparticle diffusion and Elovich models. Results show that the pseudo-second-order equation provides the best correlation for the biosorption process. The equilibrium nature of Pb(II) adsorption at 30℃ has been described by the Langmuir, Freundlich, Temkin and Redlich-Peterson isotherm models. The equilibrium data fit well on Langmuir isotherm. The monolayer adsorption capacity of Pb(II) onto Anethum graveolens as obtained from Langmuir isotherm at 30℃ was found to be 303 mg/g. This high adsorption capacity of Anethum graveolens places this biosorbent as one of the best adsorbents for removal of Pb(II) from aqueous effluents.展开更多
In this study,the distribution,transfer and fate of both polychlorinated biphenyls（PCBs）and cyanotoxins via phytoplankton routes were systematically investigated in two Chinese lakes.Results indicated that PCB adsor...In this study,the distribution,transfer and fate of both polychlorinated biphenyls（PCBs）and cyanotoxins via phytoplankton routes were systematically investigated in two Chinese lakes.Results indicated that PCB adsorption/bioaccumulation dynamics has significantly positive correlations with the biomass of green alga and diatoms.Total lipid content of phytoplankton is the major factor that influences PCB adsorption/bioaccumulation.Cyanobacterial blooms with relatively lower lipid content could also absorb high amount of PCBs due to their high cell density in the water columns,and this process was proposed as major route for the transfer of PCBs in Chinese eutrophic freshwater.According to these findings,a novel route on fates of PCBs via phytoplankton and a green bioadsorption concept were proposed and confirmed.In the practice of mechanical collections of bloom biomass from Lake Taihu,cyanotoxin/cyanobacteria and PCBs were found to be removed simultaneously very efficiently followed this theory.展开更多
Bioremediation is an efficient and popular approach for domestic wastewater treatment while the pollutant discharge standards are difficult to achieve under low-temperature conditions. The application of cold-resistan...Bioremediation is an efficient and popular approach for domestic wastewater treatment while the pollutant discharge standards are difficult to achieve under low-temperature conditions. The application of cold-resistant bacteria has gained increasing attention, but direct introduction to sewage leads to poor environmental adaptability and low microbial activity. Biochar was used as a carrier to immobilize the bacteria to improve microbial survival and activity in this study. The basic physicochemical properties of bacteria immobilized by biochar and ammonium nitrogen removal efficiency were analyzed. The process mechanism of ammonium nitrogen removal was further explored using kinetic fitting and molecular simulation calculations. The results showed that biochar immobilization of cold-resistant bacteria achieved a significantly higher ammonium nitrogen removal rate of 0.88 mg/(L·h) compared to free mixed bacteria(0.74 mg/(L·h)) and biochar alone(0.22 mg/(L·h)). It also exhibited a removal efficiency of 96.56%, which was 15.02% and 72.58% higher than that of free mixed bacteria and biochar, respectively. Adsorption kinetics further revealed that the pseudosecond-order kinetic equation was a better fit for characterizing ammonia-nitrogen removal by biocharimmobilized cold-resistant bacteria. Combining microscopic morphology analysis and molecular simulations demonstrated that enriching functional groups on biochar enhanced its NH_4~+ adsorption capacity by increasing surface activity and polarity, as well as the biodegradation ability of NH_4~+ by improving the interactions between biochar and active enzymes. These findings provide valuable insights into developing more effective ways to improve wastewater treatment efficiency under low temperatures.展开更多
The adsorption behaviour of 4 chlorophenol from aqueous solution to activated sludge was quantitatively characterized in this paper. The effects of the initial pH values, initial chlorophenol concentration and adsorb...The adsorption behaviour of 4 chlorophenol from aqueous solution to activated sludge was quantitatively characterized in this paper. The effects of the initial pH values, initial chlorophenol concentration and adsorbent dosage on bioadsorption were investigated. The maximum adsorption capacity was found to be 110.5 mg/g at 100 mg/L initial concentration. The Freundlich and Langmuir adsorption isotherms were applied to describe the biosorption processes and the isotherm constants were evaluated.展开更多
This study examines the possibility of using live spirulina to biologically remove aqueous lead of low concentration (below 50 mg/L) from wastewater. The spirulina cells were first immersed for seven days in five wast...This study examines the possibility of using live spirulina to biologically remove aqueous lead of low concentration (below 50 mg/L) from wastewater. The spirulina cells were first immersed for seven days in five wastewater samples containing lead of different concentrations, and the growth rate was determined by light at wavelength of 560 nm. The 72 h-EC50 (72 h medium effective concentration) was estimated to be 11.46 mg/L (lead). Afterwards, the lead adsorption by live spirulina cells was conducted. It was observed that at the initial stage (0–12 min) the adsorption rate was so rapid that 74% of the metal was bio- logically adsorbed. The maximum biosorption capacity of live spirulina was estimated to be 0.62 mg lead per 105 alga cells.展开更多
Bioadsorption phenomenon is more or less like a chemical reaction and several parameters are bound to affect the process. The pH, amount of adsorbent and agitation time influence the biosorptive potentiality. Hence, t...Bioadsorption phenomenon is more or less like a chemical reaction and several parameters are bound to affect the process. The pH, amount of adsorbent and agitation time influence the biosorptive potentiality. Hence, the present study on adsorption of Cr(VI) by activated Vetivera roots and Blue green algae Anabaena supports that it is an effective low cost adsorbent for the removal of Cr(VI) from plating effluent. Langmuir and Freundlich adsorption isotherm correlate the equilibrium adsorption data. In batch experiments both Vetiveria and Anabaena species were found to be cost effective biosorbent for the efficient removal of Cr(VI) from the effluent and comparatively Anabaena species was found to adsorb maximum Cr(VI) (88.86%) at a low contact time of 60 min. The data obtained from the experiments and modeling would prove useful in designing and fabricating an efficient treatment plant for Cr(VI) rich effluent.展开更多
This study was aimed to investigate Pb(II) and Cu(II) ions removal ability from aqueous solution by cassava root husks (CRH) as a cheap, sustainable and eco<span>-</span><span><span>friendly bi...This study was aimed to investigate Pb(II) and Cu(II) ions removal ability from aqueous solution by cassava root husks (CRH) as a cheap, sustainable and eco<span>-</span><span><span>friendly bioadsorbent. The CRH was characterized by Fourier Transform Infrared (FTIR) spectroscopy which indicated the availability of various functional groups for metal coordination and the result was supported by elemental analysis studies. UV-Visible spectral studies indicated the presence of oxalate (</span><img src="Edit_88f5f86a-6e96-4764-8dc0-31bbb7ac83c6.png" width="34" height="18" alt="" /></span><span><span></span><span><span>) </span><span>and it could possibly interact with metal ions to give rise to a stable chelated coordination complex which affects metal ions removal efficiency. Bioadsorption process was carried out as a function of metal concentration, contact time, pH of the solution, particle size</span></span><span>,</span><span> and dosage of the adsorbent. Experimental results indicated the optimal adsorption condition of pH 4 for both Pb(II) and Cu(II) ions, dosage of 0.1</span><span style="font-family:;" "=""> </span><span>g/0.1L and 1</span><span style="font-family:;" "=""> </span><span>g/0.1L for Pb(II) and Cu(II) ions respectively, adsorption equilibrium time of 2 and 25 minutes for Pb(II) and Cu(II) respectively, and concentration of 0.5 mg/L for both metal ions. Kinetic data best</span><span style="font-family:;" "=""> </span><span>fitted pseudo-second-order model and not </span><span>the </span><span>pseudo-first-order model. Equilibrium data best fitted </span><span>the </span><span>Freundlich model than </span><span>the </span><span>Langmuir model. Specific surface area and pore volume studies indicated that CRH is non-porous and hence rapid adsorption kinetics is expected. Supporting the experimental results, molecular modeling studies performed using Schr<span style="white-space:nowrap;">ö</span>dinger software predicted several sites in the structure capable of docking with metal ions.</span></span>展开更多
文摘In the present study we reported the feasibility of the Anethum graveolens as biosorbent to remove Pb(II) from aqueous solutions. Anethum graveolens was characterized by scanning electron microscopy and elemental analysis. The ability of Anethum graveolens to adsorb Pb(II) was investigated by using batch adsorption procedure. The effects such as pH, contact time, adsorbate concentration and biosorbent dosage on the adsorption capacity were studied. The experimental data were analysed using various adsorption kinetic models viz., the pseudo-first and second-order equations, Bangham’s equation, intraparticle diffusion and Elovich models. Results show that the pseudo-second-order equation provides the best correlation for the biosorption process. The equilibrium nature of Pb(II) adsorption at 30℃ has been described by the Langmuir, Freundlich, Temkin and Redlich-Peterson isotherm models. The equilibrium data fit well on Langmuir isotherm. The monolayer adsorption capacity of Pb(II) onto Anethum graveolens as obtained from Langmuir isotherm at 30℃ was found to be 303 mg/g. This high adsorption capacity of Anethum graveolens places this biosorbent as one of the best adsorbents for removal of Pb(II) from aqueous effluents.
基金supported by the National Natural Science Foundation of China(Nos.41276150,51679169 and 40971249)
文摘In this study,the distribution,transfer and fate of both polychlorinated biphenyls（PCBs）and cyanotoxins via phytoplankton routes were systematically investigated in two Chinese lakes.Results indicated that PCB adsorption/bioaccumulation dynamics has significantly positive correlations with the biomass of green alga and diatoms.Total lipid content of phytoplankton is the major factor that influences PCB adsorption/bioaccumulation.Cyanobacterial blooms with relatively lower lipid content could also absorb high amount of PCBs due to their high cell density in the water columns,and this process was proposed as major route for the transfer of PCBs in Chinese eutrophic freshwater.According to these findings,a novel route on fates of PCBs via phytoplankton and a green bioadsorption concept were proposed and confirmed.In the practice of mechanical collections of bloom biomass from Lake Taihu,cyanotoxin/cyanobacteria and PCBs were found to be removed simultaneously very efficiently followed this theory.
基金financial support from the Western Light Young Scholars Project,Chinese Academy of Sciences (2022)the Science and Technology Project of Sichuan Province,China (Project No.2021YFG0279)。
文摘Bioremediation is an efficient and popular approach for domestic wastewater treatment while the pollutant discharge standards are difficult to achieve under low-temperature conditions. The application of cold-resistant bacteria has gained increasing attention, but direct introduction to sewage leads to poor environmental adaptability and low microbial activity. Biochar was used as a carrier to immobilize the bacteria to improve microbial survival and activity in this study. The basic physicochemical properties of bacteria immobilized by biochar and ammonium nitrogen removal efficiency were analyzed. The process mechanism of ammonium nitrogen removal was further explored using kinetic fitting and molecular simulation calculations. The results showed that biochar immobilization of cold-resistant bacteria achieved a significantly higher ammonium nitrogen removal rate of 0.88 mg/(L·h) compared to free mixed bacteria(0.74 mg/(L·h)) and biochar alone(0.22 mg/(L·h)). It also exhibited a removal efficiency of 96.56%, which was 15.02% and 72.58% higher than that of free mixed bacteria and biochar, respectively. Adsorption kinetics further revealed that the pseudosecond-order kinetic equation was a better fit for characterizing ammonia-nitrogen removal by biocharimmobilized cold-resistant bacteria. Combining microscopic morphology analysis and molecular simulations demonstrated that enriching functional groups on biochar enhanced its NH_4~+ adsorption capacity by increasing surface activity and polarity, as well as the biodegradation ability of NH_4~+ by improving the interactions between biochar and active enzymes. These findings provide valuable insights into developing more effective ways to improve wastewater treatment efficiency under low temperatures.
文摘The adsorption behaviour of 4 chlorophenol from aqueous solution to activated sludge was quantitatively characterized in this paper. The effects of the initial pH values, initial chlorophenol concentration and adsorbent dosage on bioadsorption were investigated. The maximum adsorption capacity was found to be 110.5 mg/g at 100 mg/L initial concentration. The Freundlich and Langmuir adsorption isotherms were applied to describe the biosorption processes and the isotherm constants were evaluated.
文摘This study examines the possibility of using live spirulina to biologically remove aqueous lead of low concentration (below 50 mg/L) from wastewater. The spirulina cells were first immersed for seven days in five wastewater samples containing lead of different concentrations, and the growth rate was determined by light at wavelength of 560 nm. The 72 h-EC50 (72 h medium effective concentration) was estimated to be 11.46 mg/L (lead). Afterwards, the lead adsorption by live spirulina cells was conducted. It was observed that at the initial stage (0–12 min) the adsorption rate was so rapid that 74% of the metal was bio- logically adsorbed. The maximum biosorption capacity of live spirulina was estimated to be 0.62 mg lead per 105 alga cells.
文摘Bioadsorption phenomenon is more or less like a chemical reaction and several parameters are bound to affect the process. The pH, amount of adsorbent and agitation time influence the biosorptive potentiality. Hence, the present study on adsorption of Cr(VI) by activated Vetivera roots and Blue green algae Anabaena supports that it is an effective low cost adsorbent for the removal of Cr(VI) from plating effluent. Langmuir and Freundlich adsorption isotherm correlate the equilibrium adsorption data. In batch experiments both Vetiveria and Anabaena species were found to be cost effective biosorbent for the efficient removal of Cr(VI) from the effluent and comparatively Anabaena species was found to adsorb maximum Cr(VI) (88.86%) at a low contact time of 60 min. The data obtained from the experiments and modeling would prove useful in designing and fabricating an efficient treatment plant for Cr(VI) rich effluent.
文摘This study was aimed to investigate Pb(II) and Cu(II) ions removal ability from aqueous solution by cassava root husks (CRH) as a cheap, sustainable and eco<span>-</span><span><span>friendly bioadsorbent. The CRH was characterized by Fourier Transform Infrared (FTIR) spectroscopy which indicated the availability of various functional groups for metal coordination and the result was supported by elemental analysis studies. UV-Visible spectral studies indicated the presence of oxalate (</span><img src="Edit_88f5f86a-6e96-4764-8dc0-31bbb7ac83c6.png" width="34" height="18" alt="" /></span><span><span></span><span><span>) </span><span>and it could possibly interact with metal ions to give rise to a stable chelated coordination complex which affects metal ions removal efficiency. Bioadsorption process was carried out as a function of metal concentration, contact time, pH of the solution, particle size</span></span><span>,</span><span> and dosage of the adsorbent. Experimental results indicated the optimal adsorption condition of pH 4 for both Pb(II) and Cu(II) ions, dosage of 0.1</span><span style="font-family:;" "=""> </span><span>g/0.1L and 1</span><span style="font-family:;" "=""> </span><span>g/0.1L for Pb(II) and Cu(II) ions respectively, adsorption equilibrium time of 2 and 25 minutes for Pb(II) and Cu(II) respectively, and concentration of 0.5 mg/L for both metal ions. Kinetic data best</span><span style="font-family:;" "=""> </span><span>fitted pseudo-second-order model and not </span><span>the </span><span>pseudo-first-order model. Equilibrium data best fitted </span><span>the </span><span>Freundlich model than </span><span>the </span><span>Langmuir model. Specific surface area and pore volume studies indicated that CRH is non-porous and hence rapid adsorption kinetics is expected. Supporting the experimental results, molecular modeling studies performed using Schr<span style="white-space:nowrap;">ö</span>dinger software predicted several sites in the structure capable of docking with metal ions.</span></span>
