Preparation of Bead-on-String Nanofibers and its Application for the Removal of Bisphenol A

2015 ◽  
Vol 814 ◽  
pp. 125-131
Author(s):  
Fang Qiu ◽  
Min Le Peng ◽  
Zhi Mei Wei ◽  
Gang Zhang ◽  
Sheng Ru Long ◽  
...  

Bead-on-string nanofibers were prepared by electrospinning, in this work, . The effect of processing parameters and property of solutions on the morphology of bead-on-string nanofibers were systematically investigated. The results revealed that the morphology of beads on nanofibers transformed from spherical into spindle-like with increased concentration of solution, applied voltage and needle-collector distance. Average width of beads became smaller as increasing all the values of processing parameters. Meanwhile, the application for the removal of bisphenol A (BPA) from aqueous solution was investigated, and results showed that the bead-on-string nanofibers could effectively remove BPA from aqueous solution. The kinetic data were analyzed by the pseudo-first-order, pseudo-second-order kinetic models. The reusability of the composite nanofiber was also determined after five adsorption–desorption cycles.

2013 ◽  
Vol 741 ◽  
pp. 55-58
Author(s):  
Wen Lian Luo

The removal of Cu2+ ions from aqueous solution was studied using pickled diatomite samples. The linear Langmuir and Freundlich adsorption equations were applied to describe the equilibrium isotherms. The pseudo-first-order and pseudo-second-order models were used to determine the kinetic data. The experimental data were well fitted by the pseudo-second-order kinetic model.


2020 ◽  
Vol 3 (6) ◽  
pp. 857-870
Author(s):  
Shagufta Zafar ◽  
Muhammad Imran Khan ◽  
Mushtaq Hussain Lashari ◽  
Majeda Khraisheh ◽  
Fares Almomani ◽  
...  

AbstractThe present study investigates the removal of copper ions (Cu (II)) from aqueous solution using chemically treated rice husk (TRH). The chemical treatment was carried out using NaOH solution and the effect of contact time (tc), adsorbent dosage (Dad), initial Cu (II) concentration ([Cu]i), and temperature (T) on the percentage removals of Cu (II) (%RCu) were investigated. Different analytical techniques (FTIR, SEM, and EDX) were used to confirm the adsorption (ads) of Cu (II) onto the TRH. The ads kinetics was tested against pseudo-first-order (PFO) and pseudo-second-order (PSO) models as well as Langmuir and Freundlich isotherms. Treating RH with NaOH altered the surface and functional groups, and on the surface of RH, the ionic ligands with high electro-attraction to Cu increased and thus improved the removal efficiency. The %RCu decreased by increasing the [Cu]i and increased by increasing the ct, Dad, and T. Up to 97% Cu removal was achieved in ct of 30 min using Dad of 0.3 g [Cu]i of 25 mg L−1 and T = 280 K. The ads of Cu on TRH is endothermic, spontaneous, follows Langmuir isotherms, and exhibited a PSO kinetics. Moreover, the TRH was successfully regenerated and used for further adsorption cycles using 1 M HNO3.


2020 ◽  
Vol 24 (2) ◽  
pp. 329-333
Author(s):  
D.O. Jalija ◽  
A . Uzairu

The objective of this study was to investigate the biosorption of Cu (II) and Ni (II) ions from aqueous solution by calcium alginate beads. The effects of solution pH, contact time and initial metal ion concentration were evaluated. The results showed that maximum Cu (II) removal (93.10%) occurred at pH of 9.0, contact time of 120 minutes and initial ion concentration of 10 mg/L while that of Ni (II) was 94.6%, which was achieved at pH of 8.0, contact time of 120 minutes and initial ion concentration of 10 mg/L. The equilibrium data fitted well to the Langmuir Isotherm indicating that the process is a monolayer adsorption. The coefficients of determination, R2, values for the Langmuir Isotherm were 0.9799 and 0.9822 respectively for Cu (II) and Ni (II) ions. The values of the maximum biosorption capacity, Qo, were 10.79 and 6.25 mgg-1 respectively. The kinetic data also revealed that the sorption process could best be described by the pseudo – second order kinetic model. The R2 values for the pseudo – second order kinetic plots for Cu (II) and Ni (II) were 0.9988 and 0.9969 respectively. These values were higher than those for the pseudo – first order plots. The values of the biosorption capacity qe obtained from the pseudo – second order plots were very close to the experimental values of qe indicating that the biosorption process follows the second order kinetics. This study has therefore shown that calcium alginate beads can be used for the removal of Cu (II) and Ni (II) ions from wastewaters. Keywords: Keywords: Adsorption, Calcium alginate, Isotherm, Langmuir, Pseudo- first order, Pseudo-second order


2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Juanjuan Zhao ◽  
Yujiao Sun ◽  
Fachao Wu ◽  
Minjian Shi ◽  
Xurui Liu

Antibiotic residues and antibiotic resistance genes (ARGs) pose a great threat to public health and food security via the horizontal transfer in the food production chain. Oxidative degradation of amoxicillin (AMO) in aqueous solution by thermally activated persulfate (TAP) was investigated. The AMO degradation followed a pseudo-first-order kinetic model at all tested conditions. The pseudo-first-order rate constants of AMO degradation well-fitted the Arrhenius equation when the reaction temperature ranged from 35°C to 60°C, with the apparent activate energy of 126.9 kJ·mol−1. High reaction temperature, high initial persulfate concentration, low pH, high Cl− concentration, and humic acid (HA) concentration increased the AMO degradation efficiency. The EPR test demonstrated that both ·OH and SO4·− were generated in the TAP system, and the radical scavenging test identified that the predominant reactive radical species were SO4·− in aqueous solution without adjusting the solution pH. In groundwater and drinking water, AMO degradation suggested that TAP could be a reliable technology for water remediation contaminated by AMO in practice.


2021 ◽  
Author(s):  
Thi-Thuy Luu ◽  
Duy-Khoi Nguyen ◽  
Tu Thi Phuong Nguyen ◽  
Thien-Hoang Ho ◽  
Van-Phuc Dinh ◽  
...  

Abstract To remove Ni(II) ions from an aqueous solution, researchers used red mud modified by chitosan (RM/CS) material as a new adsorbent. According to the findings, the surface area of red mud is nearly doubled after being treated with chitosan, from 68.6 m2/g to 105.7 m2/g. The effects of pH solution, contact time, and material dosage on the Ni(II) uptake were examined. In comparison with the pseudo-first-order and pseudo-second-order models, the intra-diffusion model was the most suitable kinetic model for the Ni(II) removal. Besides, the three-parameter Sips model was used to predict the Ni(II) adsorption of RM/CS from aqueous solution. Furthermore, the Langmuir maximum Ni(II) uptake capacity of this material was 31.66 mg/g at 323K, which was higher than red mud and several other natural materials. Notably, thermodynamic investigations demonstrated that Ni(II) adsorption on RM/CS is both exothermic and physic.


2021 ◽  
Author(s):  
Muhammad Yasir ◽  
Tomáš Šopík ◽  
Rahul Patwa ◽  
Dušan Kimmer ◽  
Vladimír Sedlařík

Abstract This study emphasizes rapid and simultaneous adsorptive removal of estrogenic hormones (EHs): estrone (E1), 17β-estradiol (E2), 17α-ethinylestradiol (EE2), and estriol (E3) from wastewater using recycled waste cigarette electrospun nanofibers (WCENFs). The nanofibers exhibited a small diameter (196±65 nm) and large surface area (18.05 m 2 /g), along with a strong affinity towards all EHs by adsorption due to abundant hydrogen bonding interactions. A one-step high-performance liquid chromatography technique was developed to detect each EH present in the solution simultaneously. The adsorption kinetics helps select optimum conditions for the large-scale removal process, so experimental data using pseudo-first-order, pseudo-second-order, intra-particle diffusion, Elovich, and fractional power models were fitted. It was found that E1, E2, and EE2 followed pseudo-second-order kinetics while E3 followed pseudo-first-order kinetic models. The total adsorption capacity on WCENFs was determined to be 2.14 mg/g, whereas the individual adsorption capacities of E1, E2, EE2, and E3 were found to be 0.551, 0.532, 0.687, and 0.369 mg/g, respectively. The percentage efficiency of WCENFs was highest with EE2 ~64.3% and least with E3 ~34.6%. Adsorption-desorption studies revealed that WCENFs could repeatedly be used four times. The reported results indicate a significant potential of WCENFs to be an effective sorbent and portable filter for simultaneous estrogenic hormone removal. WCENFs filter is a suitable alternative to commercial Cellulose acetate filters.


2021 ◽  
Author(s):  
Muhammad Yasir ◽  
Tomas Sopik ◽  
Lenka Lovecka ◽  
Dusan Kimmer ◽  
Vladimir Sedlarik

Abstract This study focuses on characterizing the adsorption kinetics of sex hormones (estrone, 17β-estradiol, 17α-ethinylestradiol, and estriol) on electrospun nanofibrous polymeric nanostructures based on cellulose acetate, polyamide, polyethersulfone, polyurethane, and polyacrylonitrile. The materials’ structure possessed fibers of average diameter in the range 174-330 nm, while its specific surface area equaled 10.2 to 20.9 m2/g. The adsorption-desorption process was investigated in four cycles to determine the reusability of the sorption systems. A one-step high-performance liquid chromatography technique was developed to detect concurrently each hormone present in the solution. Experimental data was applied to gauge adsorption kinetics with the aid of pseudo-first-order, pseudo-second-order, and intraparticle diffusion models; findings showed that estrone, estradiol, and ethinylestradiol followed pseudo-second-order kinetics, while estriol followed pseudo-first-order kinetics. It was observed that polyurethane had maximum adsorption capacities of 0.801, 0.590, 0.736, and 0.382 mg/g for estrone, 17β-estradiol, 17α-ethinylestradiol, and estriol, respectively. The results revealed that polyurethane had the highest percentage efficiency of estrogens removal at ~58.9% and lowest for polyacrylonitrile at ~35.1%. Consecutive adsorption-desorption cycles demonstrated that polyurethane maintained high efficiency, even after being used four times compared with the other polymers. The findings indicate the studied nanostructures have the potential to be effective sorbents for eradicating these estrogens concurrently from the environment.


Author(s):  
Marek Lipovský ◽  
Maroš Sirotiak ◽  
Maroš Soldán

Abstract Removal of copper from aqueous solution on the natural and modified clinoptilolite was studied under static conditions. Batch adsorptions of copper were performed to investigate the effects of contact time and initial metal ion concentration. The Freundlich and Langmuir adsorption isotherms were used to analyse the experimental data. The kinetic analyses of the adsorption processes were performed using the pseudo-first-order and pseudo-second-order kinetic models.


2015 ◽  
Vol 93 (10) ◽  
pp. 1083-1087 ◽  
Author(s):  
Ali Issa Ismail

Graphene is a newly discovered material and is considered to be the new wonder material for many applications. The recent possibility of obtaining pure and fully characterized graphene opens the door to the study of the adsorption of toxic materials on graphene. The adsorption behavior of p-nitrophenol on graphene was studied in aqueous medium. The effect of each of pH, temperature, and dosage was emphasized. The highest calculated adsorption capacity of 4-nitrophenol was found to be 15.5 mg/g, assuming Langmuir fitting starting from 11.1 mg/g initial concentration at 298 K and pH = 6. Fitting the data using the Freundlich isotherm model predicted a favorable adsorption process (n > 1). The rise and saturation areas of the isotherms were fitted as pseudo first-order and pseudo second-order processes, respectively, with relatively good fit (k1 = 0.0023/s, k2 = 0.68 g mg−1 s−1). The thermodynamic properties indicated a spontaneous and exothermic process.


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