scholarly journals Antimony Removal from Water by a Chitosan-Iron(III)[ChiFer(III)] Biocomposite

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 351 ◽  
Author(s):  
Byron Lapo ◽  
Hary Demey ◽  
Tanya Carchi ◽  
Ana Sastre
Keyword(s):  
Material Characterization ◽  
Point Of Zero Charge ◽  
Iron Oxyhydroxide ◽  
X Ray Diffraction ◽  
Amino Groups ◽  
X Ray ◽  
Chitosan Matrix ◽  
Pseudo Second Order ◽  
Adsorption Desorption ◽  
Order Rate Equation

The presence of antimony(III) in water represents a worldwide concern, mainly due to its high toxicity and carcinogenicity potential. It can be separated from water by the use of sustainable biopolymers such as chitosan or its derivatives. The present study applied chitosan modified with iron(III) beads to Sb(III) removal from aqueous solutions. The resulting material performed with a high adsorption capacity of 98.68 mg/g. Material characterization consisted of Raman spectroscopy (RS), X-ray diffraction (XRD), scanning electron microscope observations (SEM-EDX), Fourier transform infrared spectroscopy (FTIR) and point of zero charge (pHpzc). The adsorption study included pH study, effect of initial concentration, kinetics, ion effect, and reusability assessment. The RS, XRD, and FTIR results indicated that the main functional groups in the composite were related to hydroxyl and amino groups, and iron oxyhydroxide species of α-FeO(OH). The pHpzc was found to be 7.41. The best adsorption efficiency was set at pH 6. The equilibrium isotherms were better fitted with a non-linear Langmuir model, and the kinetics data were fitted with a pseudo-second order rate equation. The incorporation of iron into the chitosan matrix improved the Sb(III) uptake by 47.9%, compared with neat chitosan (CS). The material did not exhibit an impact in its performance in the presence of other ions, and it could be reused for up to three adsorption–desorption cycles.

Behaviours of direct yellow 12 adsorption on mesoporous carbons with different pore geometries

2018 ◽  
Vol 2017 (1) ◽  
pp. 219-228
Author(s):  
Fengling Liu ◽  
Ziyan Guo ◽  
Hui Qiu ◽  
Xia Lu ◽  
Hua Fang ◽  
...  
Keyword(s):  
Mesoporous Carbons ◽  
X Ray Diffraction ◽  
Pore Characteristics ◽  
X Ray ◽  
Transmission Electron ◽  
Cylindrical Pores ◽  
Pseudo Second Order ◽  
Hexagonally Ordered ◽  
Adsorption Desorption ◽  
Interconnected Pore

Abstract Four kinds of mesoporous carbons, C1-h-w, C2-h-h, C3-s-w, and C4-s-h, with different pore geometries were prepared and characterised, and their adsorption behaviours with aqueous direct yellow 12 (DY-12) were investigated. The results of X-ray diffraction and transmission electron microscopy show that C1-h-w and C3-s-w have wormlike pore characteristics, whereas C2-h-h and C4-s-h have 2-D hexagonally arranged pores. According to the N2 adsorption/desorption results, the specific surface area of C1-h-w (1,378 m2/g) is the largest among the four carbons. The adsorption isotherms could be effectively fitted using the Langmuir model. The maximum adsorption amounts of C1-h-w, C2-h-h, C3-s-w and C4-s-h are 0.968 mmol/g, 0.726 mmol/g, 0.161 mmol/g and 0.156 mmol/g, respectively. The pseudo-second-order rate constants of C1-h-w (39.8 g/(mmol·min)) and C2-h-h (7.28 g/(mmol·min)) are substantially larger than those of C3-s-w (0.0046 g/(mmol·min)) and C4-s-h (0.014 g/(mmol·min)), indicating that an open and interconnected pore geometry is favourable for DY-12 adsorption. Furthermore, DY-12 diffusion in 2-D hexagonally ordered cylindrical pores is superior to that in wormlike pores due to the smoothness of the channels in the former. External mass transfer and intraparticle diffusion both play roles in the adsorption process.

scholarly journals Selective adsorption of PHC and regeneration of washing effluents by modified diatomite

2020 ◽  
Vol 81 (10) ◽  
pp. 2066-2077
Author(s):  
Zhuoqi Xu ◽  
Gengbo Ren ◽  
Yanying Zhu ◽  
Xiaodong Ma ◽  
Hongrui Li ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Selective Adsorption ◽  
Low Cost ◽  
Soil Washing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Monolayer Adsorption ◽  
Pseudo Second Order ◽  
Adsorption Desorption ◽  
Modified Diatomite

Abstract Selective removal of petroleum hydrocarbons (PHCs) from soil washing effluents is the key to the surfactant-enhanced soil washing technology. In this study, the diatomite was modified by nonionic surfactant TX-100 and applied in the selective adsorption of PHCs in the soil washing effluents. The modified diatomites were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, N2 adsorption/desorption and X-ray photoelectron spectroscopy respectively. The adsorption process followed the pseudo-second-order model and the adsorption isotherms indicated that the interaction between PHCs and modified diatomite was monolayer adsorption. The important operating factors such as TX-100 dosage, adsorbent dosage, time and temperature were optimized. With the participation of the low-cost adsorbent TX3-Db with high adsorption capacity, the recovery efficiency of the washing effluents was still up to 78.9% after three cycles. A selective adsorption mechanism, based on steric hindrance and electrostatic repulsion, was proposed to explain the removal of PHCs from washing effluents.

Synthesis and catalytic performance of MCM-41 modified with tetracarboxylphthalocyanine

2013 ◽  
Vol 67 (4) ◽  
Author(s):  
Ya-Ping Zhang ◽  
Ke-Chuang Xue ◽  
Wei-Ping Zhang ◽  
Chao Song ◽  
Rong-Lan Zhang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Performance ◽  
Conversion Ratio ◽  
X Ray Diffraction ◽  
Amino Groups ◽  
N2 Adsorption ◽  
X Ray ◽  
Adsorption Desorption ◽  
Mcm 41 ◽  
Scanning Electron

AbstractA series of tetracarboxylphthalocyanines (MPc(COOH)4, M = H, Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II)) were anchored onto MCM-41 by the following procedures: functionalization of MCM-41 with (EtO)3SiCH2CH2CH2NH2 reacting with surface Si-OH, and anchoring MPc(COOH)4 onto MCM-41 with a substitution reaction between chloroformyl and amino groups. The samples were characterized by infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, N2 adsorption-desorption, and X-ray photoelectron spectroscopy. Catalytic activity of oxidation was tested using solutions of ethanethiol in petroleum ether and thiophene in octane; CoPc-CONH-MCM-41 displayed the highest conversion ratio of 90.15 % and 93.79 %, respectively.

Adsorption of Dye from Wastewater onto ZnO Nanoparticles-Loaded Zeolite: Kinetic, Thermodynamic and Isotherm Studies

2020 ◽  
Vol 234 (2) ◽  
pp. 255-278
Author(s):  
Ahmed Samer Elfeky ◽  
Hanan Farouk Youssef ◽  
Ahmed Shafek Elzaref
Keyword(s):  
Removal Efficiency ◽  
Kinetic Studies ◽  
Second Order ◽  
Exchange Property ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
X Ray ◽  
Best Fitting ◽  
Pseudo Second Order ◽  
Adsorption Desorption

AbstractThe adsorption process of methylene blue (MB) and its removal from aqueous solution at initial pollutant concentration range of 1–7 ppm was investigated. Zeolite-A (Z) and its ZnO-loaded species (Z/ZnO) were prepared via microwave technique from natural resource and applied for dye removal. The loading of ZnO was governed by the cation exchange property of zeolite, followed by calcination. Experimentally, Z and Z/ZnO were tested using X-ray Diffraction (XRD), Fourier-Transform Infrared (FTIR), Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and N2 adsorption-desorption. The examined parameters such as concentration of dye, contact time, ZnO dose and solution pH were traversed. Three isothermal models were analyzed. Kinetic studies indicated that, the adsorption of MB matched with pseudo-second order model. The maximum removal efficiency at pH 3, increased from 67.8% for Z to 94.8% for Z/ZnO modified with 3% ZnO loads (Z/ZnO(3%)). Parameters such as ΔH, ΔS, ΔG, S* and Ea were thermodynamically calculated. Langmiur isotherm and pseudo-second order models were the best fitting for the obtained data. The results indicated that, the adsorption of MB dye is spontaneous and endothermic, the removal efficiency is favored by increasing the temperature. ZnO-zeolite has much higher adsorption capacity for eliminating MB dye than that of the un-loaded zeolite.

scholarly journals Sorption of Pb(II) from Aqueous Solutions by Acid-Modified Clinoptilolite-Rich Tuffs with Different Si/Al Ratios

2019 ◽  
Vol 9 (12) ◽  
pp. 2415 ◽  
Author(s):  
Mohamed Abatal ◽  
Atl V. Córdova Quiroz ◽  
María T. Olguín ◽  
América R. Vázquez-Olmos ◽  
Joel Vargas ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Contact Time ◽  
Point Of Zero Charge ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
Batch Studies ◽  
X Ray ◽  
Pseudo Second Order ◽  
Modified Clinoptilolite ◽  
Adsorbent Dose

The removal of Pb(II) from aqueous solutions by acid-modified clinoptilolite-rich tuff was investigated in this work. Clinoptilolite-rich tuff samples were treated using H2SO4 at different concentrations. Prior to and following acid treatment, the samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared spectroscopy (FTIR). The pH of the point of zero charge (pHPZC) was also determined as part of this characterization. Batch studies were studied to investigate Pb(II) removal as a function of contact time, initial Pb(II) concentration, adsorbent dosage, and solution pH. The results of the XRD and SEM techniques showed that clinoptilolite is the main mineral of the non- and acid-treated natural zeolite samples. However, EDS analysis indicated that the Si/Al ratio increases as the exchangeable ions decrease with increasing acid concentrations. The optimum conditions for Pb(II) removal for samples with 4.37 ≤ Si/Al ≤ 7.9 were found to be as follows: Contact time of 60–360 min, pH: 6–8, and adsorbent dose of 6 mg g−1; whereas for acid-modified clinoptilolite-rich tuffs with 9.01 ≤ Si/Al ≤ 9.52, these conditions were as follows: Contact time of 1440 min, pH: 8–10, and adsorbent dose of 10 mg g−1. The experimental data were analyzed by kinetic and isotherms models. The results showed that the sorption of Pb(II) on samples with Si/Al ratios of 4.37, 5.31, and 7.91 were in agreement with the pseudo-second order and Langmuir isotherm with qm = 48.54, 37.04, and 14.99 mg g−1, respectively, while the kinetic data and isotherm for samples with 9.01 ≤ Si/Al ≤ 9.52 were found to fit the pseudo-first order and Freundlich model.

scholarly journals Kinetics, isotherm and thermodynamic studies of S2− adsorption by (SBA-15)-Hg (II)

2021 ◽  
Author(s):  
Xiao-Dong Li ◽  
Qing-Zhou Zhai
Keyword(s):  
Nitrogen Adsorption ◽  
Order Equation ◽  
Adsorption Properties ◽  
Adsorption Efficiency ◽  
X Ray Diffraction ◽  
Santa Barbara ◽  
Isothermal Adsorption ◽  
X Ray ◽  
Pseudo Second Order ◽  
Adsorption Desorption

Abstract The nano-mesoporous material SBA (Santa Barbara Amorphous)-15 was synthesized using the hydrothermal method. Hg2+ was adsorbed by SBA-15 and then the S2− in the aqueous phase by (SBA-15)-Hg(II), with the hope that materials with better S2− adsorption properties can be obtained. The relevant materials were characterized by X-ray diffraction, scanning electron microscopy, 77 K nitrogen adsorption-desorption, and related product characteristics were determined. In this work, the adsorption conditions of S2− onto (SBA-15)-Hg(II) were optimized. Adsorption efficiency reached about 92% and the adsorption capacity 55.02 mg/g. Studies of the system's adsorption kinetics showed that the pseudo-second-order equation applies. The thermodynamic results indicated that ΔG0 < 0, ΔH0 = −28.56 kJ/mol, ΔS0 = −81.136 J/(mol·K), and that adsorption is exothermic, enthalpy decreases and the reaction is spontaneous. This accords with Freundlich isothermal adsorption equation.

Enhancement of the adsorption properties of two natural bentonites by ion exchange: equilibrium, kinetics and thermodynamic study

Clay Minerals ◽  
2020 ◽  
Vol 55 (2) ◽  
pp. 132-141
Author(s):  
Ali Boukhemkhem ◽  
Alejandro H. Pizarro ◽  
Carmen B. Molina
Keyword(s):  
Ion Exchange ◽  
Point Of Zero Charge ◽  
Exchange Equilibrium ◽  
Anionic Dyes ◽  
X Ray ◽  
Intraparticle Diffusion Model ◽  
Initial Ph ◽  
Pseudo Second Order ◽  
Bentonite Clays ◽  
Adsorption Desorption

ABSTRACTIn this investigation, Maghnia (Ma) and Mostaganem (Ms) bentonite clays, mined from west Algeria, with no prior affinity for anionic dyes, were modified by simple ion exchange with aqueous Fe3+ solutions, followed by calcination at 500°C. The resulting materials, Fe-Ma and Fe-Ms, respectively, were employed as adsorbents for methyl orange. The starting materials and the two adsorbents were characterized by X-ray diffraction, N2 adsorption–desorption isotherms, Brunauer–Emmett–Teller specific surface area and X-ray fluorescence and by determining the point of zero charge. The effects of various variables, such as initial dye concentration, contact time, adsorbent dose, initial pH and adsorption temperature, were studied. The kinetics were well described by the pseudo-second-order model and the mechanism was determined from the intraparticle diffusion model, while corresponding isotherms fitted better to the Freundlich model. Thermodynamic parameters showed that the adsorption process was endothermic, spontaneous and physical in nature, accompanied by an increase of entropy.

Axially Chiral Bis(α-amino Acid)s and Their Deamino Analogues. Synthesis and Configurational Assignment

1998 ◽  
Vol 63 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Miloš Tichý ◽  
Luděk Ridvan ◽  
Miloš Buděšínský ◽  
Jiří Závada ◽  
Jaroslav Podlaha ◽  
...  
Keyword(s):  
Amino Acid ◽  
Nmr Spectra ◽  
Building Blocks ◽  
X Ray Diffraction ◽  
Amino Groups ◽  
X Ray ◽  
Configurational Assignment ◽  
Symmetry Properties ◽  
Axially Chiral ◽  
Polymeric Structures

The axially chiral bis(α-amino acid)s cis-2 and trans-2 as possible building blocks for polymeric structures of novel type of helicity were prepared. Their configuration has been determined by NMR spectroscopy and, in the case of the trans-isomer, confirmed by single-crystal X-ray diffraction. Analogous pair of stereoisomeric diacids cis-3 and trans-3, devoid of the amino groups, was also prepared and their configuration assigned. The observed differences in the NMR spectra of cis- and trans-isomers of 2 and 3 are discussed from the viewpoint of their different symmetry properties.

scholarly journals Zeolite NaP1 Functionalization for the Sorption of Metal Complexes with Biodegradable N-(1,2-dicarboxyethyl)-D,L-aspartic Acid

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2518
Author(s):  
Dorota Kołodyńska ◽  
Yongming Ju ◽  
Małgorzata Franus ◽  
Wojciech Franus
Keyword(s):  
Experimental Data ◽  
Aspartic Acid ◽  
Ph Value ◽  
Complexing Agents ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Modified Zeolite ◽  
X Ray ◽  
Slow Release Fertilizers ◽  
Pseudo Second Order

The possibility of application of chitosan-modified zeolite as sorbent for Cu(II), Zn(II), Mn(II), and Fe(III) ions and their mixtures in the presence of N-(1,2-dicarboxyethyl)-D,L-aspartic acid, IDHA) under different experimental conditions were investigated. Chitosan-modified zeolite belongs to the group of biodegradable complexing agents used in fertilizer production. NaP1CS as a carrier forms a barrier to the spontaneous release of the fertilizer into soil. The obtained materials were characterized by Fourier transform infrared spectroscopy (FTIR); surface area determination (ASAP); scanning electron microscopy (SEM-EDS); X-ray fluorescence (XRF); X-ray diffraction (XRD); and carbon, hydrogen, and nitrogen (CHN), as well as thermogravimetric (TGA) methods. The concentrations of Cu(II), Zn(II), Mn(II), and Fe(III) complexes with IDHA varied from 5–20 mg/dm3 for Cu(II), 10–40 mg/dm3 for Fe(III), 20–80 mg/dm3 for Mn(II), and 10–40 mg/dm3 for Zn(II), respectively; pH value (3–6), time (1–120 min), and temperature (293–333 K) on the sorption efficiency were tested. The Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin adsorption models were applied to describe experimental data. The pH 5 proved to be appropriate for adsorption. The pseudo-second order and Langmuir models were consistent with the experimental data. The thermodynamic parameters indicate that adsorption is spontaneous and endothermic. The highest desorption percentage was achieved using the HCl solution, therefore, proving that method can be used to design slow-release fertilizers.

Efficient adsorption of chlorpyrifos onto modified activated carbon by gamma irradiation; a plausible adsorption mechanism

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohamed S. Yahia ◽  
Ahmed S. Elzaref ◽  
Magdy B. Awad ◽  
Ahmed M. Tony ◽  
Ahmed S. Elfeky
Keyword(s):  
Gamma Irradiation ◽  
Area Measurement ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Pseudo First Order ◽  
Kinetics Of

Abstract Commercial Granulated Active Carbon (GAC) has been modified using 10 Gy dose Gamma irradiation (GAC10 Gy) for increasing its ability of air purification. Both, the raw and treated samples were applied for removing Chlorpyrifos pesticide (CPF) from ambient midair. Physicochemical properties of the two materials were characterized by Fourier Transform Infrared (FT-IR) and Raman spectroscopy. The phase formation and microstructure were monitored using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), supported with Energy-Dispersive X-ray (EDX). The Surface area measurement was detected using BET particle size prosometry. Obtained outcomes showed that, the maximum adsorption capacity, given by Langmuir equations, was greatly increased from 172.712 to 272.480 mg/g for GAC and GAC10 Gy, respectively, with high selectivity. The overall removal efficiency of GAC10 Gy was notably comparable to that of the original GAC-sorbent. The present study indicated that, gamma irradiation could be a promising technique for treating GAC and turned it more active in eliminating the pesticides pollutants from surrounding air. The data of equilibrium has been analyzed by Langmuir and Freundlich models, that were considerably better suited for the investigated materials than other models. The process kinetics of CPF adsorbed onto both tested carbon versions were found to obey the pseudo first order at all concentrations with an exception at 70 mg/l using GAC, where, the spontaneous exothermic adsorption of Chlorpyrifos is a strong function for the pseudo-first order (PFO) and pseudo second order (PSO) kinetics.

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