scholarly journals Fabrication of Cotton Linter-Based Adsorbents by Radiation Grafting Polymerization for Humic Acid Removal from Aqueous Solution

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 962 ◽  
Author(s):  
Jifu Du ◽  
Zhen Dong ◽  
Yuxuan Pi ◽  
Xin Yang ◽  
Long Zhao

Two kinds of cotton linter-based adsorbents were synthesized by grafting dimethylaminoethyl methacrylate (DMAEMA) on cotton linter via radiation grafting polymerization, followed by further quaternization (QCL) or protonation (PCL). The effect of radiation dose and monomer concentration on grafting yield was optimized. The synthesized adsorbents were characterized by Fourier transform infrared spectrometry (FT-IR), Thermogravimetric Analysis (TGA), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The adsorption behaviors of the two adsorbents toward humic acid (HA) were investigated and discussed. pH effect studies showed that QCL was pH-independent, whereas PCL was just suitable for HA adsorption with pH < 6. The adsorption kinetics of the PCL and QCL adsorbent for HA removal were better described by pseudo-second-order kinetic mode and reached equilibrium in 40 min. The adsorption isotherms of the PCL and QCL adsorbent were well fitted with both Langmuir and Freundlich isotherm models, for which adsorption capacity reached 250 mg/g and 333 mg/g at pH 6, respectively. XPS analysis revealed the ratio of two amino group species at different pH, suggesting that the interaction mechanism of the adsorbent and HA was electrostatic adsorption.

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
José María Rivera ◽  
Susana Rincón ◽  
Cherif Ben Youssef ◽  
Alejandro Zepeda

Mesoporous metal-organic framework-5 (MOF-5), with the composition Zn4O(BDC)3, showed a high capacity for the adsorptive removal of Pb(II) from 100% aqueous media. After the adsorption process, changes in both morphology and composition were detected using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) system, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analysis. The experimental evidence showed that Zn(II) liberation from MOF-5 structure was provoked by the water effect demonstrating that Pb(II) removal is not due to ionic exchange with Zn. A kinetic study showed that Pb(II) removal was carried out in 30 min with a behavior of pseudo-second-order kinetic model. The experimental data on Pb(II) adsorption were adequately fit by both the Langmuir and BET isotherm models with maximum adsorption capacities of 658.5 and 412.7 mg/g, respectively, at pH 5 and 45°C. The results of this work demonstrate that the use of MOF-5 has great potential for applications in environmental protection, especially regarding the removal of the lead present in industrial wastewaters and tap waters.


2020 ◽  
Vol 10 (14) ◽  
pp. 4745
Author(s):  
Xiaoyu Du ◽  
Chihiro Kishima ◽  
Haixin Zhang ◽  
Naoto Miyamoto ◽  
Naoki Kano

In this study, chitosan beads modified with sodium dodecyl sulfate (SDS) were successfully synthesized and employed for the removal of chromium(VI) (Cr(VI)). The adsorption performance of the adsorbent (SDS-chitosan beads) was examined by batch experiments. The partition coefficient (PC) as well as the adsorption capacity were evaluated to assess the true performance of the adsorbent in this work. The adsorbent (SDS-chitosan beads) showed a maximum Cr(VI) adsorption capacity of 3.23 mg·g−1 and PC of 9.5 mg·g−1·mM−1 for Cr(VI). The prepared adsorbent was characterized by different techniques such as scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and Fourier transform-infrared spectroscopy (FT-IR). We used inductively coupled plasma mass spectrometry (ICP-MS) for the determination of Cr(VI) in solution. The experimental data could be well-fitted by pseudo-second-order kinetic and Langmuir isotherm models. The thermodynamic studies indicated that the adsorption process was favorable under the higher temperature condition. The SDS-modified chitosan beads synthesized in this work represent a promising adsorbent for removing Cr(VI).


2016 ◽  
Vol 74 (7) ◽  
pp. 1644-1657 ◽  
Author(s):  
Mona El-Sayed ◽  
Gh. Eshaq ◽  
A. E. ElMetwally

In our study, Mg–Al–Zn mingled oxides were prepared by the co-precipitation method. The structure, composition, morphology and thermal stability of the synthesized Mg–Al–Zn mingled oxides were analyzed by powder X-ray diffraction, Fourier transform infrared spectrometry, N2 physisorption, scanning electron microscopy, differential scanning calorimetry and thermogravimetry. Batch experiments were performed to study the adsorption behavior of cobalt(II) and nickel(II) as a function of pH, contact time, initial metal ion concentration, and adsorbent dose. The maximum adsorption capacity of Mg–Al–Zn mingled oxides for cobalt and nickel metal ions was 116.7 mg g−1, and 70.4 mg g−1, respectively. The experimental data were analyzed using pseudo-first- and pseudo-second-order kinetic models in linear and nonlinear regression analysis. The kinetic studies showed that the adsorption process could be described by the pseudo-second-order kinetic model. Experimental equilibrium data were well represented by Langmuir and Freundlich isotherm models. Also, the maximum monolayer capacity, qmax, obtained was 113.8 mg g−1, and 79.4 mg g−1 for Co(II), and Ni(II), respectively. Our results showed that Mg–Al–Zn mingled oxides can be used as an efficient adsorbent material for removal of heavy metals from industrial wastewater samples.


2018 ◽  
Vol 9 (3) ◽  
pp. 202-212 ◽  
Author(s):  
Mohammad Nasir Uddin ◽  
Jahangir Alam ◽  
Syeda Rahimon Naher

The adsorption capacity of chromium(III) from synthetic waste water solution by a low cost biomaterial, Jute Stick Powder (JSP)was examined. A series of batch experiments were conducted at different pH values, adsorbent dosage and initial chromium concentration to investigate the effects of these experimental conditions. To analyze the metal adsorption on to the JSP, most common adsorption isotherm models were applied. To study the reaction rate, the kinetic and diffusion models were also applied. The morphological structure and variation of functional groups in the JSP before and after adsorption was examined by scanning electron microscope (SEM) and Fourier transform infrared spectrometry (FT-IR). Maximum chromium removal capacities of JSP was 84.34%with corresponding equilibrium uptake 8.4 mg/g from 50 mg/L of synthetic metal solution in 60 minutes of contact time at pH = 6.0 and 28 °C with continuous stirring at 180 rpm. The percent sorption of the biomass decreased with increasing concentration of metal ion but increased with decreasing pH, increasing contact time and adsorbent doses. Data for this study indicated a good correspondence with both isotherms of Langmuir and Freundlich isotherm. The analysis of kinetic indicated that Chromium was consistent with the second-order kinetic adsorption model. The rate of removal of Cr(III) ions from aqueous solution by JSP was found rapid initially within 5-30 minutes and reached in equilibrium in about 40 minutes. The investigation revealed that JSP, a low cost agricultural byproduct, was a potential adsorbent for removal of heavy metal ions from aqueous solution.


2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Ying-Xia Ma ◽  
Yong-Xin Ruan ◽  
Dan Xing ◽  
Xue-Yan Du ◽  
Pei-Qing La

Ethylenediamine functionalized magnetic expanded graphite decorated with Fe3O4 nanoparticles (MEG-NH2) was fabricated by one-pot solvothermal method. The as-prepared MEG-NH2 nanohybrids were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and Zeta potential analyzer. The effects of Fe3O4 content in MEG-NH2 nanohybrids, pH, initial concentration, contact time, and dosage on adsorption properties of the MEG-NH2 nanohybrids for Ag(I) from aqueous solution were investigated by batch experiments. The pseudo-first-order and the pseudo-second-order kinetic models were utilized to study adsorption kinetics. The experimental data was also analyzed with Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherm models. The results show that Ag(I) was reduced to silver in the process of the adsorption by MEG-NH2 nanohybrids; the experimental data was better fitted to pseudo-second-order model and Langmuir isotherm model which revealed that the adsorption process was a chemical adsorption by the formation of silver on the surface of MEG-NH2 nanohybrids.


Author(s):  
Fateme Poorsharbaf Ghavi ◽  
Fereshteh Raouf ◽  
Ahmad Dadvand Koohi

Abstract The elimination of diclofenac traces from aqueous environments is important. In this research, the effect of alkaline (NaOH) pretreatment on clinoptilolite before its modification with a surfactant (HDTMA) for diclofenac adsorption under the speculation of the sole presence of diclofenac in the aqueous solution is investigated. The results are compared through isotherm, kinetic, and thermodynamic studies and supplemented by FTIR, SEM, BET, and the zeta potential analyses. The contact time was investigated in a 0–180-min range. The pH effect was studied in a range of 5–10 because of diclofenac dissociation below pH = 5. The effect of the temperature on diclofenac adsorption was also considered by establishing the experiments at 25, 35, and 45 °C. For HDTMA-modified clinoptilolite, Temkin, and for NaOH-HDTMA-modified clinoptilolite, Dubinin–Radushkevich, and Freundlich isotherm models and in both cases, the pseudo-second-order kinetic model fitted the experimental data best. All the enthalpy and the entropy changes were negative, suggesting exothermic adsorption with a decrease in the degree of freedom of diclofenac anions after the adsorption. Furthermore, diclofenac physisorption was confirmed through isotherm and kinetic studies.


Author(s):  
Seyedeh Mahsa Seyed Danesh ◽  
Shahab Shariati ◽  
Hossein Faghihian

Objective: In this study, amine functionalized magnetite Kit-6 silica nanocomposite (Fe3O4@SiO2@Kit-6-NH2) was synthesized as an adsorbent for removing Carmoisine food dye from aqueous solutions. Method: The nanocomposite was chemically synthesized and was characterized by X-ray diffraction analysis (XRD), vi-brating sample magnetometer (VSM), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FT-IR). Taguchi orthogonal array experimental design method was used to op-timize the experimental conditions including adsorbent amount, pH of solution, amount of salt, the volume of sample and contact time. Pseudo first-order, pseudo second-order, intra-particle diffusion and Elovich kinetic models were investigated to study the kinetic parameters of sorption process. Results: The kinetic data corresponded to the pseudo second-order kinetic model with R2 = 0.9999. Also, adsorption data were analyzed using Langmuir, Freundlich and Temkin isotherm models. The results indicated that the data were well fitted to the Freundlich isotherm model (R2 = 0.9984, n=1.0786). The reusability tests showed the proposed nanocomposite can be used more than 8 cycles with removal efficiency higher than 90%. Conclusion: The applicability study of proposed nanocomposite proved its ability for efficient removal of Carmoisine dye from real aqueous samples.


2019 ◽  
Vol 20 (7) ◽  
pp. 1775 ◽  
Author(s):  
Rongqi Chen ◽  
Xi Zhao ◽  
Juan Jiao ◽  
Yan Li ◽  
Min Wei

In this study, a surface chemical-modified rice husk biochar with abundant amino groups and disulfide bonds for the removal of cadmium was prepared using cystamine dihydrochloride as a modification ligand and glutaraldehyde as a crosslinker. The biochars were characterized by Fourier transform infrared spectrometry (FTIR), elemental analysis, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), thermogravimetry analysis (TGA), and nitrogen sorption (BET) before and after modification. The adsorption properties of the modified biochars for Cd (II) were investigated in detail via adsorption isotherm models, adsorption kinetics models, and selective adsorption experiments. The surfaces of the cystamine-modified biochars with granular nanopolymers of sufficient functional groups of primary amine and disulfide linkage rendered the biochar surface more conducive to electrostatic attraction and surface complexation. The theoretical maximum adsorption capacity of the modified biochars (81.02 mg g−1) was almost 10-fold greater than that of the raw biochars (8.347 mg g−1) for Cd (II). Besides, the cystamine-modified biochars had a better affinity for Cd (II) compared to other heavy metals (Zn, As, Cd, Co, Ni, Cr), showing six-fold greater affinity for Cd (II) than Zn2+. The results of this study indicate that the modification of biochars derived from rice husks shows great potential in the removal of Cd (II) from contaminated water.


2020 ◽  
Vol 26 (5) ◽  
pp. 200339-0
Author(s):  
Cheng Yao ◽  
Min Wang ◽  
Wenju Jiang ◽  
Yao Chen

A novel N-doped mesoporous carbon (AC-N) was prepared by impregnation method on the basis of cypress-derived activated carbon for methylene blue (MB) removal. The introduction of nitrogen atoms with appropriate proportion could improve MB adsorption capacity of the prepared mesoporous carbon (AC-N). AC-N obtained at optimized modification (1 mol/L urea) had an excellent MB adsorption of 910.95 mg/g and the removal efficiency was ca. 91% at 25℃. Elemental analysis showed that the nitrogen content of AC-N was high up to 2.6%. A large specific surface area (S<sub>BET</sub>) 1,215 cm<sup>3</sup>/g and an obvious mesoporous structure with a high mesopore to total pore volume ratio (V<sub>mes</sub>/V<sub>tot</sub>) 91% was observed on AC-N. X-ray photoelectron spectroscopy (XPS) results indicated a successful doping of nitrogen element into the mesoporous carbon and pyridinic-N, pyrrolic-N and amino-N were existed in AC-N. Scanning electron microscope (SEM) and Fourier transform infrared spectrometry (FTIR) were also used to characterize this prepared adsorbent. MB adsorption kinetics parameters and isotherm results on the produced carbon were well fitted by the pseudo-second-order kinetic model and Langmuir model. According to the thermodynamic analysis, the adsorption of MB on AC-N was found to be an endothermic, spontaneous process in nature.


2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Lu Thi Mong Thy ◽  
Nguyen Thi Chi Linh ◽  
Nguyen Thi Tuyet Tram ◽  
Tran Hoang Tu ◽  
Le Tan Tai ◽  
...  

This study is aimed at studying the adsorption of methylene blue (MB) from aqueous solutions by nickel ferrite/graphene oxide (NGO) nanocomposite. The nanocomposite was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, energy dispersive X-ray, Brunauer-Emmett-Teller-specific surface area, and vibrating sample magnetometer analyses. The interactive effects of critical variables including pH, initial concentration, and contact time on the adsorption capacity of NGO for MB were studied using response surface methodology (RSM) according to composite central design. In RSM models, the predicted values agreed well with verification experiments, with a high correlation coefficient of 0.9887. The adsorption process followed the pseudo-second-order kinetic and Langmuir isotherm models. The maximum capacity for adsorption of MB onto NGO was found to be 476.19 mg/g. Based on these results, NGO has the potential as an efficient adsorbent for the removal of MB from water.


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