scholarly journals Porous Multifunctional Phenylcarbamoylated-β-Cyclodextrin Polymers for Rapid Removal of Organic Pollutants

Author(s):  
He Wang ◽  
Congzhi Liu ◽  
Xiaofei Ma ◽  
Yong Wang

Abstract In this work, a series of porous multifunctional cyclodextrin (CD) polymers were fabricated using tetrafluoroterephthalonitrile (TFTPN) as the rigid crosslinker for the condensation of different functional phenylcarbamoylated-β-cyclodextrin derivatives to afford three preliminary polymerized adsorption materials such as poly nitrophenylcarbamoylated-β-cyclodextrin (NO2-CDP), poly trifluoromethylphenylcarbamoylated-β-cyclodextrin (F-CDP), poly chlorophenylcarbamoylated-β-cyclodextrin polymers (Cl-CDP) and a mix β- cyclodextrin polymer (X-CDP) prepared via a secondary crosslinking procedure of the above three materials. The X-CDP preparation process connects the `pre-formed nanoparticles and increases the presence of linkers inside the particles. At the same time, X-CDP exhibited porous structure with various functional groups such as nitro, chlorine, fluorine and hydroxyl. Those special characteristics render this material with good adsorption ability towards various pollutants in water, including tetracycline, ibuprofen, dichlorophenol, norfloxacin, bisphenol A, naphthol. Especially the maximum adsorption capacity for tetracycline at equilibrium reached 230.15 mg·g− 1, which is competitive with the adsorption capacities of other polysaccharides adsorbents. X-CDP removed organic contaminants much more quickly than other adsorbents, reaching almost ~ 95% of its equilibrium in only 30 s. The main adsorption process of the pollutants by X-CDP fitted the pseudo-second-order kinetic and Langmuir isotherm well, indicating that the adsorption process is monolayer adsorption. Moreover, X-CDP possessed the good reusability where the pollutant removal rate was only reduced 8.3% after five cycles.

2017 ◽  
Vol 55 (1) ◽  
pp. 54
Author(s):  
Le Cao The ◽  
Vu Minh Tan ◽  
Phan Thi Binh

Composite based on eucalyptus leaf and polyaniline (EL-PANi) was prepared by chemical polymerization method. It showed that the function groups belonging to polyaniline and eucalyptus leaf were found through IR analysis and the nanostructure of composite was explained by SEM images. The adsorption of  Pb2+ was carried out onto composite in aqueous solution via varying pH, contact time, and its initial concentration. The experimental adsorption data fitted well into Freundlich adsorption isotherm model (r2 = 0.9873). The adsorption process followed pseudo-second order kinetic with r2 = 0.9995. The maximum adsorption capacity of Pb2+ onto that composite was 172.4138 mg/g  by Langmuir equation and KF was 58.7527 mg/g by Freundlich one.


2019 ◽  
Vol 79 (1) ◽  
pp. 126-136 ◽  
Author(s):  
Yan Chen ◽  
Wei Chen ◽  
Quanzhou Chen ◽  
Changhong Peng ◽  
Dewen He ◽  
...  

Abstract In this study, a novel poly ligand exchanger-Zn(II)-loaded resin was designed to effectively remove ammonia-nitrogen (NH3-N) from wastewater. The surface morphology and structure of the Zn-loaded resin were characterized using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and Fourier transform infrared spectroscopy (FTIR), respectively. SEM shows the surfaces of the Zn(II)-loaded resin were rough and nonporous and EDS demonstrated that Zn2+ was loaded onto the resin successfully. In addition, the combination form of Zn(II) with NH3-N adsorption reagent was revealed by FTIR spectra; the complex could be R-N-R-O-Zn-O-R-N-R and R-N-R-(O-Zn)2. The kinetics and equilibrium of the NH3-N adsorption onto the Zn(II)-loaded resin has been investigated. The effects of pH, reaction time, and temperature on NH3-N removal from wastewater by Zn(II)-loaded resin were investigated, and the results showed that the maximum adsorption capacity reached 38.55 mg/g at pH 9.54 at 298 K in 240 min. The adsorption ability of the modified resin decreased with an increase in temperature. Moreover, the NH3-N adsorption followed a pseudo-second-order kinetic process. The kinetic data demonstrated that the adsorption process might be limited by a variety of mechanisms. The study can provide the scientific foundation for the extensive application of a novel poly ligand exchanger-Zn(II)-loaded resin to remove NH3-N from wastewater.


Author(s):  
Xiangyang Zhang ◽  
Xiuli Han ◽  
Chun Chang ◽  
Pan Li ◽  
Hongwei Li ◽  
...  

AbstractActivated carbon derived from raw corncob (CCAC), which prepared with steam as the activating agent, was used to adsorb bisphenol S (BPS) from aqueous solution. Characterizations of CCAC were measured by using the Brunauer-Emmett-Teller, scanning electron microscopy, and Fourier transform infrared spectroscopy. Adsorption conditions including initial BPS concentration, contact time, adsorbent dosage and pH were optimized by response surface methodology (RSM). The results show that adsorption equilibrium was well described by the Langmuir and Koble–Corrigan models. The maximum monolayer adsorption capacity of BPS was found to be 617.29 mg g−1 at 298 K. Based on the thermodynamic parameters analysis, the BPS adsorption process was turned out to be spontaneous and exothermic. The adsorption process of BPS was well described by the pseudo-second-order kinetic model. It also found that H-bonding, π–π interaction, and electrostatic interaction were the main mechanisms in the process of BPS adsorption onto the CCAC.


2021 ◽  
Vol 83 (6) ◽  
pp. 1429-1445
Author(s):  
Xiulei Fan ◽  
Jiajun Zhang ◽  
Ya Xie ◽  
Dezhi Xu ◽  
Yu Liu ◽  
...  

Abstract Application of sewage sludge biochar as an adsorbent for pollutant removal has obtained special attention due to their low cost and surface functionality. In this research, sludge–tire composite biochar (STB) was successfully prepared through co-pyrolysis at 300, 500 and 700 °C, respectively. Cadmium (Cd) and tetracycline (TC) were selected as the target pollutant. The results indicated that STB has the highest surface area (49.71 m2/g), more inorganic minerals (Kaolinite) as well as relatively stable physicochemical properties with 10% tire particles (TP) at 700 °C. The adsorption results indicated that the pseudo-second-order equation and Langmuir isotherm model could better describe the adsorption of Cd2+ and TC by STB. The maximum adsorption capacity of Cd2+ and TC was 50.25 mg/g and 90.09 mg/g, respectively. The main mechanism of the adsorption process of STB for Cd mainly involves anion binding adsorption and ion exchange. The main mechanism of the adsorption process of STB for TC mainly involves complexation and cation exchange. The present study could set a scientific foundation for further research on the recycle of sewage sludge and tires.


Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 608
Author(s):  
Aixin Yu ◽  
Yuankun Liu ◽  
Xing Li ◽  
Yanling Yang ◽  
Zhiwei Zhou ◽  
...  

As a key parameter in the adsorption process, removal rate is not available under most operating conditions due to the time and cost of experimental testing. To address this issue, evaluation of the efficiency of NH4+ removal from stormwater by coal-based granular activated carbon (CB-GAC), a novel approach, the response surface methodology (RSM), back-propagation artificial neural network (BP-ANN) coupled with genetic algorithm (GA), has been applied in this research. The sorption process was modeled based on Box-Behnben design (BBD) RSM method for independent variables: Contact time, initial concentration, temperature, and pH; suggesting a quadratic polynomial model with p-value < 0.001, R2 = 0.9762. The BP-ANN with a structure of 4-8-1 gave the best performance. Compared with the BBD-RSM model, the BP-ANN model indicated better prediction of the response with R2 = 0.9959. The weights derived from BP-ANN was further analyzed by Garson equation, and the results showed that the order of the variables’ effectiveness is as follow: Contact time (31.23%) > pH (24.68%) > temperature (22.93%) > initial concentration (21.16%). The process parameters were optimized via RSM optimization tools and GA. The results of validation experiments showed that the optimization results of GA-ANN are more accurate than BBD-RSM, with contact time = 899.41 min, initial concentration = 17.35 mg/L, temperature = 15 °C, pH = 6.98, NH4+ removal rate = 63.74%, and relative error = 0.87%. Furthermore, the CB-GAC has been characterized by Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET). The isotherm and kinetic studies of the adsorption process illustrated that adsorption of NH4+ onto CB-GAC corresponded Langmuir isotherm and pseudo-second-order kinetic models. The calculated maximum adsorption capacity was 0.2821 mg/g.


2021 ◽  
Author(s):  
Maoling Wu ◽  
Ling Ding ◽  
Jun Liao ◽  
Yong Zhang ◽  
Wenkun Zhu

Abstract In this work, the efficient extraction of uranium in solution using Al2O3-SiO2-T was reported. Kinetics and isotherm models indicated that the removal process of uranium onAl2O3-SiO2-T accorded with pseudo-second-order kinetic model and Langmuir isotherm model, which showed that the adsorption process was a uniform mono-layer chemical behavior. The maximum adsorption capacity of Al2O3-SiO2-T reached 738.7 mg g-1, which was higher than AlNaO6Si2 (349.8 mg g-1) and Al2O3-SiO2-NT (453.1 mg g-1), indicating that the addition of template could effectively improve the adsorption performance of Al2O3-SiO2 to uranium. Even after five cycles of adsorption-desorption, the removal percentage of uranium on Al2O3-SiO2-T remained 96%. Besides, the extraction efficiency of uranium on Al2O3-SiO2-T was 72.5% in simulated seawater, which suggested that the Al2O3-SiO2-T was expected to be used for uranium extraction from seawater. Further, the interaction mechanism between Al2O3-SiO2-T and uranium species was studied. The results showed that the electrostatic interaction and complexation played key roles in the adsorption process of Al2O3-SiO2-T to uranium.


2012 ◽  
Vol 550-553 ◽  
pp. 2255-2258
Author(s):  
Bing Bing Liu ◽  
Hua Yong Zhang ◽  
Lu Yi Zhang

Phosphate adsorption from aqueous solution using slag was investigated as the function of pH, contact time and adsorbent dosage. The results showed that the optimum value of pH was 2. Both Langmuir isotherm and Freundlich isotherm model were fit to describe the phosphate adsorption, and the maximum adsorption capacity from Langmuir model calculated was 9.09 mg/L. The adsorption process on slag followed pseudo second-order kinetic. Due to the relatively high adsorption capacity, the slag has the potential for application to removal phosphate from wastewater.


1970 ◽  
Vol 23 ◽  
pp. 102-105 ◽  
Author(s):  
Puspa Lal Homagai ◽  
Hari Paudyal

Saponified apple waste gel was prepared in wet condition with calcium hydroxide at highly alkaline medium. The effect of initial concentration, contact time and pH of the solution was investigated. The maximum adsorption capacity onto this adsorbent was investigated for Fe(III), Cd(II), Zn(II) and Pb(II) at their optimal pH of 3, 6, 4.5 and 3.5 respectively. Langmuir isotherm and pseudo second-order kinetic model gave better explanation of the adsorption process. For binary mixture of Zn(II) and Cd(II), the separation factor and effect on adsorption capacity for both the metals were investigated.Keywords: adsorption, saponified apple waste, bioadsorption.DOI: 10.3126/jncs.v23i0.2103Journal of Nepal Chemical Society, Vol. 23, 2008/2009 Page: 102-105


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Mona A. Shouman ◽  
Nady A. Fathy ◽  
Soheir A. Khedr ◽  
Amina A. Attia

The waste of palm branches (PB) was tested for its ability to remove chromium (VI) from aqueous solution by batch and column experiments. Palm branches chemically modified with an oxidizing agent (sulphuric acid) then coated with chitosan and surfactant (hexadecyl trimethyl ammonium bromide surfactant, HDTMA), respectively, were carried out to improve the removal performance of PB. The results of their Cr (VI) removal performances are pH dependent. The adsorption data could be well interpreted by the Langmuir, Freundlich, and Flory-Huggins isotherm models. The maximum adsorption capacity obtained from the Langmuir model for the chitosan coated oxidized palm branches is 55 mg/mg. The adsorption process could be described by pseudo-second-order kinetic model. The intraparticle diffusion study revealed that film diffusion might be involved. The biosorbents were successfully regenerated using 1 M HCL solution.


2021 ◽  
Author(s):  
Khalil ahmad ◽  
Izaz Ali Shah ◽  
Sharafat Ali ◽  
Muahammad Tariq Khan ◽  
Muhammad Bilal Ahmed Qureshi ◽  
...  

Abstract In this work, a novel calcium (Ca) doped ferrihydrite adsorbent was evaluated for the enhanced adsorption of fluoride (F) from the aqueous phase. The adsorbent properties, adsorption behavior, and mechanism were systematically evaluated. The synthesized adsorbent exhibited tremendous performance in a broad range of temperature and pH. Interestingly, the presence of co-existing anions such as NO3-, SO42-, Cl-, and natural organic matter (NOM) have no considerable effect on the adsorption of fluoride from water. The adsorption process was best fitted to the pseudo-second order kinetic model and the Langmuir isotherm. The prepared adsorbent exhibited a maximum adsorption capacity of 53.21 mg/g for the uptake of fluoride from water. The regeneration results confirmed that adsorbent could retain their original adsorption capacity after five regeneration cycles. Results from the current study suggested that Ca-doped ferrihydrite has the application potential for the enhanced adsorption of fluoride from the water phase.


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